University of Southern California Dissertations and Theses

Energy performance of different building forms: HEED simulations of equivalent massing models in diverse building surface aspect ratios and locations in the US

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Energy performance of different building forms: HEED simulations of equivalent massing models in diverse building surface aspect ratios and locations in the US

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Content i

Energy Performance of Different Building Forms

HEED Simulations of Equivalent Massing Models in Diverse Building Surface Aspect Ratios
and Locations in the US

By

Fahad Allheedan

Presented to the
FACULTY OF THE
SCHOOL OF ARCHITECTURE
UNIVERSITY OF SOUTHERN CALIFORNIA
In partial fulfillment of the
Requirements of degree
MASTER OF BUILDING SCIENCE

August 2019

ii

ACKNOWLEDGEMENTS

I am very grateful to the great God who has provided me with some people who supported me on
this thesis research, academically, financially and emotionally, without whom I could not have
completed this work.

Academically, Douglas E. Noble, the thesis chair and director of Chase L. Leavitt Master of
Building Science Program, Kyle Konis and Joon-Ho Choi, the second and third committee
members, in University of Southern California School of Architecture, helped me to perfect my
thesis research in more significance and efficiency.

Financially, I would like to thank the King of Saudi Arabia who sponsors me to study my second
master’s degree and gives me the opportunity to learn anything that offers development and pace
to the world. Also, I would like to thank the scholarships that offered to me from USC School of
Architecture and Society of Building Science Educators. Last but not least, thanks to Prof.
Abdullah Allheedan, my father.

Emotionally, to my mother, Modi, who loves me, and I love her very much. She encourages me to
succeed and to go ahead my graduate studies with knowing that would make me far away from
her, but she did not stop me. To my father, who made my ambition extremely high to be like him.
I hope I am doing well like what he did. To my wife, Lamees, who misses our time together, but
she never lost her patient on me. To my grandmother who always prays for me and gives me
blessing feelings. To my young sisters and brothers who are always wishing me the greatest luck.
Thank you all for your backing.

iii

COMMITTEE MEMBERS

Chair
Douglas E. Noble
Associate Professor
University of Southern California
dnoble@usc.edu

Second Committee Member
Kyle Konis
Assistant Professor
University of Southern California
kkonis@usc.edu

Third Committee Member
Joon-Ho Choi
Assistant Professor
University of Southern California
joonhoch@usc.edu

iv

ABSTRACT:
The façade is a line between indoor and outdoor, which makes it one of the most significant topics
in building science. It has been chosen to test the energy-efficient of the most basic common
architectural building forms, tall thin, medium-medium (cube) and short wide building forms, that
are using precast concrete façades with standard thermal comfort. This may help develop the
precast concrete envelope market in the U.S. and make people more confident in precast concrete
envelopes starting from the governments and architectural firms because usually wood, steel, stone
and glass are used as a building envelope in America, but precast concrete envelopes are used more
than any façade material in the Middle East.
Three different residential building forms have been tested. The tall thin model dimensions are
9.75m x 9.75m x 29.26m (32ft x 32ft x 96ft), ten stories, and the medium-medium model has
14.63m x 14.63m x 14.63m (48ft x 48ft x 48ft), five stories. The short wide model is 30.48m x
30.48m x 2.93m (100ft x 100ft) x 9.6ft, one story. They have been designed by using the same US
energy building codes and standards. Also, they have been used almost the same equal total floor
area, ~1000m
2
(10,764 square feet), massing volume, ~3000m
3
(105,944 cubic feet) plan aspect
ratio, 1:1, and Window to Wall Ratio (WWR), 25%, at three diverse climate locations in the US,
Los Angeles, New York, and Las Vegas, with an additional three variables, which are building
orientation, ±0°, -30° and -45°, infiltration system, 2.0, 1.5 and 0.3 SLA/ 4.0, 3.0 and 0.6 ACH,
and controlled blinds in three modes, fixed, automated with sun rays and automated with
temperature, to find which precast concrete model saves the energy more by using a Building
Energy Modeling (BEM) software tool, Home Energy Efficient Design (HEED).
The results show in general the short wide model is the most energy efficient massing in all
different conditions, which makes it first. Secondly, the cube-shaped model follows closely, which
is 6% higher energy consumption than the short wide mass. Lastly, the tall thin building form with
the precast concrete façade performs much worse. The energy consumption of the tall thin precast
concrete façade in all conditions is 46% more than the short wide mass and 40% more than the
cube mass. Usually, this ordinal is valid even though all the specifications and approximately the
total floor area, massing volume, plan aspect ratio and WWR are the same, but the percentages
may change a little bit, depends on the additional variables.
KEYWORDS:
Concrete Envelope, thermal mass, building form, façade, solar heat, cooling, heating, indoor
temperature, Energy Use Intensity (EUI) and HEED.
HYPOTHESIS:
1- Short wide concrete façade buildings have more opportunity to save energy than tall thin ones
if they have the fundamentally the same specifications and conditions.
2- Energy Use Intensity (EUI) results for cube concrete buildings are in between the EUI for tall
thin and short wide buildings.
RESEARCH OBJECTIVES:
Explore the energy efficiency of the common basic building forms that are using a precast concrete
façade in different national climates for saving energy by simulated each different massing and
investigating the total energy consumption, indoor temperature, total heating and cooling HVAC
output, heat loss, Energy Use Intensity (EUI) and hours when no cooling and heating needed.
Then, comparing each massing to see how much each one saves energy to prove how the precast
concrete façade is significant and saving energy in the United States.
v

TABLE OF CONTENTS

ACKNOWLEDGEMENTS ......................................................................................................... ii
COMMITTEE MEMBERS ........................................................................................................ iii
ABSTRACT .................................................................................................................................. iv
KEYWORDS ................................................................................................................................ iv
HYPOTHESIS.............................................................................................................................. iv
RESEARCH OBJECTIVES ....................................................................................................... iv
1. AN INTRODUCTION TO THE ENERGY PERFORMANCE OF FAÇADES ................ 1
1.1 Why Study Energy Performance of Concrete Façades? ................................................. 2
1.1.1 Energy use threatens the planet .................................................................................. 2
1.1.2 Clear observations can help architects and developers ............................................. 3
1.2 Energy Simulation is an Effective Method for Analysis .................................................. 3
1.2.1 Energy simulation is reasonably accurate .................................................................. 4
1.2.2 Energy study of concrete façades is important .......................................................... 4
1.2.3 Energy simulation is cost-effective .............................................................................. 5
1.2.4 HEED has been selected as a BEM tool ...................................................................... 5
1.3 An Overview of Characteristics of Precast Concrete Façades ........................................ 6
1.3.1 What are precast concrete façades? ............................................................................ 6
1.3.2 Advantages of precast concrete façades ..................................................................... 6
1.3.3 Disadvantages of precast concrete façades ................................................................. 7
1.4 The Scope of Research Includes Geometry, Climate ....................................................... 7
1.4.1 There are many possible geometry variables to examine ......................................... 8
1.4.2 Climate is a primary determinate of building façade performance ....................... 10
1.5 Summary ............................................................................................................................ 10
2. EXAMINING PRECAST, MASSING ENERGY, AND CLIMATE-SELECTION ........ 12
2.1 How Have Others Conducted Similar Studies? ............................................................. 12
2.1.1 Attia and De Herde did a study of how accurate HEED is ..................................... 12
2.1.2 Milne and Liggett did a study of who can use HEED ............................................. 13
2.1.3 Sabunas and Kanapickas did multi scenarios study by using HEED .................... 13
2.2 Why Precast Concrete was Selected as the Façade Material ........................................ 13
2.2.1 Precast is a common façade material in the Middle East ....................................... 14
2.2.2 Precast has a high thermal mass ............................................................................... 14
2.2.3 Precast has low material costs ................................................................................... 15
vi

2.2.4 Precast is fast, accurate and clean ............................................................................. 16
2.3 Massing Energy Efficiency ............................................................................................... 16
2.3.1 Why is massing energy efficiency the key concept for performance? ................... 17
2.3.2 What other metrics were considered? ...................................................................... 18
2.4 Three Locations are Chosen for Conducting Simulations ............................................ 18
2.4.1 Los Angeles is a mild climate ..................................................................................... 18
2.4.2 New York is cold climate............................................................................................ 18
2.4.3 Las Vegas is hot and dry climate ............................................................................... 19
2.4.4 Why these three are appropriate selections ............................................................. 19
2.5 Summary ............................................................................................................................ 20
3. METHODOLOGY ................................................................................................................. 21
3.1 Schematic Diagram of Methodology ............................................................................... 21
3.2 Branching Scenarios ......................................................................................................... 22
3.3 Three Basic Massing Schemes are Selected .................................................................... 22
3.3.1 Tall thin massing ......................................................................................................... 22
3.3.2 Medium-medium massing .......................................................................................... 22
3.3.3 Short wide massing ..................................................................................................... 23
3.3.4 Why these three were selected ................................................................................... 23
3.4 Three Different Locations are Selected ........................................................................... 23
3.4.1 Los Angeles .................................................................................................................. 24
3.4.2 New York ..................................................................................................................... 25
3.4.3 Las Vegas ..................................................................................................................... 26
3.5 Assembling and Examining the Results .......................................................................... 26
3.6 Summary ............................................................................................................................ 27
4. DATA AND RESULTS .......................................................................................................... 29
4.1 Inputs .................................................................................................................................. 29
4.1.1 First common steps for all models ............................................................................ 30
4.1.2 Tall thin model steps .................................................................................................. 33
4.1.3 Medium-medium model steps ................................................................................... 40
4.1.4 Short wide model steps ............................................................................................... 43
4.1.5 Last common steps for all models ............................................................................. 46
4.1.6 Advanced steps for all models ................................................................................... 62
4.1.7 Advanced steps for tall thin model............................................................................ 65
4.1.8 Advanced steps for medium-medium model ............................................................ 67
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4.1.9 Advanced steps for short wide model ....................................................................... 69
4.2 Outputs ............................................................................................................................... 71
4.2.1 Energy Use Intensity (EUI)........................................................................................ 71
4.2.2 Total site energy use ................................................................................................... 73
4.2.3 Hours of passive, heating and cooling times ............................................................ 74
4.2.4 Indoor temperature .................................................................................................... 78
4.2.5 Envelope performance ............................................................................................... 90
4.2.6 Energy performance ................................................................................................... 95
4.3 Summary .......................................................................................................................... 100
5. DISCUSSION ........................................................................................................................ 102
5.1 Evaluation of Workflow .................................................................................................. 102
5.1.1 Minor differentiations in modeling volumes and total floor areas ...................... 103
5.1.2 Sizes and spaces between windows ......................................................................... 104
5.1.3 Reasons of uncomfortable hours ............................................................................. 104
5.2 Comparison of Different Models Results ...................................................................... 105
5.2.1 Comparing the EUI results between the three models.......................................... 105
5.2.2 Hours of passive, heating and cooling times .......................................................... 106
5.2.3 Indoor temperature .................................................................................................. 111
5.2.4 Envelope and energy performances ........................................................................ 112
5.3 Summary .......................................................................................................................... 113
6. CONCLUSION, SCOPE, AND FUTURE WORK ............................................................ 114
6.1 Conclusion and Scope of Work ...................................................................................... 114
6.1.1 Conclusion of work ................................................................................................... 114
6.1.2 Scope of work ............................................................................................................ 116
6.2 Evaluation of the Methodology ...................................................................................... 117
6.2.1 Improvement to current workflow ......................................................................... 118
6.2.2 Future work .............................................................................................................. 118
6.3 Summary .......................................................................................................................... 119
REFERENCES: ........................................................................................................................ 120
1

1. AN INTRODUCTION TO THE ENERGY PERFORMANCE OF FAÇADES

Concrete façades are much less common in the United States than they are in the Middle East,
where most buildings have a concrete façade. Concrete building envelopes in America may not be
used because it takes more time and effort in a building site, not like steel, stone, or wood. In Saudi
Arabia, for example, they use different techniques like cast-in, pre-stressed, and precast concrete
envelopes. Precast concrete is faster, more accurate and cleaner as a building envelope technique
than any other building envelope technique in the regions around Saudi Arabia. Therefore, precast
concrete is the chosen façade material.

By using HEED, one of the chosen BEM software tools, to create energy models of precast
concrete façade and simulating them in some United States cities, the results can show the energy
efficiency of these buildings. However, many owners, architects, and contractors think concrete
is usually used when buildings are huge, and they may have some thoughts that precast concrete
façade is generally used in tall or wide buildings. Therefore, the tested models should be small
sizes. and all models should use dissimilar forms but the same massing volume, total floor area,
WWR, plan aspect ratio and standardized specification and details to make sure that the
competition between all models is fair and equal. Consequently, tall thin, short wide and something
between (cube) are the tested building forms. All should be tested in diverse climates and in largest
development cities in America to show the building performances of precast concrete façade’s
results in the U.S. All building materials are precast concrete such as foundation and substructure,
depth and volume depend on building form and load, and flat plate structure with flat roof and
gypsum board ceiling. All models have standard designs, systems, controls, specifications and
details. For example, the selected cooling and heating systems are the Energy Code Minimum
Furnace and Air Conditioner in the US energy codes, 13.0 SEER, Seasonal Energy Efficiency
Ratio, and 78% AFUR, Annual Fuel Utilization Efficiency. No special building elements, designs,
systems, controls, specifications and details like renewable energy techniques, water management,
overhangs, shades, skylights, balconies, courtyards, lightings, appliances, people activities,
surroundings like landscape and buildings, and interior designs like colors and interior wall thick.
Excluding, three additional variables, about design, system and control, rather than different
building forms and locations as mentioned before. The first variable is about design, rotating the
model orientation in three slopes, first slope, ±0°, second slope, -30°, and third slope, -45°. The
second variable is about the system, changing the infiltration in three systems, Sealed HVAC Ducts
+ Building Air Barrier, 2.5 SLA/ 5.0 ACH, HERS, Verified Air Sealed + Quality Insulation
Installation, 1.5 SLA/ 3.0 ARCH, and Passive House Standard, 0.3 SLA/ 0.6 ACH. Third variable
is about building control, automating the Light Venetian Blinds in three modes, fixed mode, at
45°, closed mode, when sun is on window and indoors is above comfort low or 3°F below comfort
high in winter, and last mode is automated with temperature, at 45° or closed tight hourly when
indoor temperature reaches 3°F below comfort high.

Precast concrete is one of the common building materials in the Middle East, architecturally and
structurally. The selected precast concrete exterior wall is 20cm (8’’) thick, which is found in
HEED, light color, with a rigid foam board R13 continuous. The exterior wall U value equals 0.07
for all three models. Window glass is clear argon filled double pane Low-E squared in insulated
vinyl frame, U=0.30, SHGC=0.25, Tvis=0.52. These options are available in HEED. Also, these
selected options are chosen becase they all meet the residential requirements for all the states in
2

the US. In the United States, the common façade material is wood, stone and glass because those
are the available materials in the American markets. Precast concrete is not used because it is not
familiar and has no great factories offer decent precast concrete quality. When people in the United
States start using concrete, they were using an old technique which is Cast-in concrete in the site,
takes time, effort and more money, which is a huge disadvantage. Nevertheless, nowadays,
Americans should know more about precast techniques which can make concrete faster and ready
to use as a façade as the other materials. If there is a high demand for precast concrete envelopes,
markets will start to offer them with a top specification in high-quality factories, which is this one
of the thesis goals.

1.1 Why Study Energy Performance of Concrete Façades?

Façades are not only used to shape the appearance of the buildings because they also impact the
indoor climate, operating cost and energy consumption. This insight is important because it
determines the cooling and heating loads. Besides, this information is important in defining the
lighting demands of a building. It is important to study the energy performance of concrete façades
because this insight is important to designers, architects, and clients. As for the occupants, this
information will help them in defining the satisfaction, comfort, and performance (Alexander et
al. 2016) By studying energy performance, the readers are introduced to energy demands and
different levels of indoor natural lighting. Currently, there are considerable differences that come
with concrete façades. These differences bring about considerable changes in the performance of
these materials. Thus, it is important to study their energy performance to define the economic and
material demands. Depending on the type of façade required, information on energy performance
will guide on the decision to make. Primarily, this information is important in reducing the overall
energy demands of a building (Anderson. 2014). The energy performance of concrete façades
helps in separating the cooling and orientation demands of a building. The changes in time call for
effective use of energy. Therefore, information on energy performance will be of importance in
defining the energy strategy conservation that should be employed in the energy future. Ultimately,
the knowledge of energy performance will help in conserving energy and improving the
maintenance costs of the building. Currently, the focus has been on improving the energy demands;
and thus, the study on energy performance will be of importance in meeting this goal (Clarke.
2001).

1.1.1 Energy use threatens the planet

Evidently, the use of energy determines the energy development. Processes included in energy
development include production, distribution, and consumption of energy. Clearly, the
consumption of energy threatens the existence of plants and animals in the world. Clarke believes
that the demands come with the production and consumption of energy puts pressure on the
biodiversity of the planet. Information from conservation groups and surveys from the health of
the world depict the pressure that comes with different methods of producing and consuming
energy. It is important to study the energy performance of the façades because there is an ever-
growing demand for resources. Through the energy study, concerned personnel will be able to gain
knowledge on some of the most important strategies that can be put into consideration to maximize
3

the efficient use of energy. Eventually, the energy study will help in creating an effective
production system. Energy use in buildings is defined by the combination of power and heat
systems. These systems are used to heat and cool the building. The total energy consumed by these
buildings should be reduced through the study of energy performance of concrete façades (Clarke.
2007). Information on the energy performance will be of importance in decreasing the pressure
and effect that comes with different energy sources in the world. According to statistics done by
Clarke; it is evident that commercial building can come with different energy needs. Out of the
different energy needs, space heating and cooling has been identified as having a large impact. The
effect that comes with this energy use can be reduced through the study energy performance.

1.1.2 Clear observations can help architects and developers

Clear observations made on the type of material and its energy requirements are important in
helping the architects and developers to make accurate observations on the building. For instance,
computer simulations on the energy of the different types of façade indicate that there is a
considerable difference in the demands. This difference in demand indicates that the level of indoor
natural lighting will be different. To meet, the lighting requirements it is important to make a clear
observation of the type of façade being used (Erdly and Schwartz. 2004). Through the study of
energy performance, other parameters which affect the design and comfortability of the buildings
are defined; for instance, the overall solar factor. This factor is important as it helps the architects
in separating the orientation of the building from the overall energy needs. Nowadays, it is
important to improve the energy efficiencies of buildings. The energy efficiency of these building
depends on the design interventions which ought to be carefully analyzed.

The study of energy performance and efficiencies of the concrete façades help to minimize energy
consumptions as it introduces the architects and developers to some of the techniques and
initiatives like the solar control coupled with cooling techniques (Popovic and Arnold. 2000). Also,
the observations made help in other aspects like the performance and applicability of other systems
and controls like the ventilation structure. The study on energy performance helps the developers
to identify the best flow of good air in the different designs of buildings. Broadly, the insight that
comes with the study helps in making clear observations on the different aspects of the building.

1.2 Energy Simulation is an Effective Method for Analysis

Energy simulation is an effective method for analysis because discrepancies that come between
the simulation and results are few. In the context of methods of analysis in the construction
industry, the effectiveness of a BEM tool is measured by the discrepancy between the simulation
and the actual measured performance of the building. This method is accurate because the
discrepancies are few. The uncertainties that come with the building assessment and design are
reduced since the approximations made on the model input match (Redmon and Forbess. 2002).
Simulation results and measurement match with the actual building. However, the effectiveness of
this approach is dependent on the quality of input data and other applied methods in the simulation
engine. According to the ASHRAE Standard 140-2017 "Standard Method of Test for the
Evaluation of Building Energy Analysis Computer Programs (ANSI Approved)", the technical
4

capability and the ability of this method are high (Taylor-Firth. 1991). A good example is the
ability of the computer program to calculate the thermal performance. Criteria for assessing the
effectiveness of this method of the analysis show that the approach is effective in measuring the
desired performance and properties of a virtual building. Energy simulation accurately represents
the virtual model of the actual building. This software is effective in predicting the performance
of the buildings. The effectiveness that comes with the approach is clearly seen from the various
mass and energy flows predicted by the software. Through the computer simulations, architects
are able to make buildings with considerations made on the type, comfort, and efficiency. The
competence that comes with the simulation engineers is of importance in determining the
efficiency of this tool. Simulation engineers and quality of input data determines the accuracy of
this tool.

1.2.1 Energy simulation is reasonably accurate

Clearly, this approach is reasonably accurate because it depends on inputs which can be effectively
selected to bring about the accurate information. In fact, there are no studies and extensive
evidence on the inconsistencies that come with the energy simulation approach. Some of the
uncertainties that may come with this tool include the use of unrealistic occupancy data. These
uncertainties can be addressed through the accuracy of input data; for instance, the use of real-time
occupancy schedule and metered electricity consumption data (Torgal et al. 2016). These tools are
reasonably accurate because there are little disparities between the actual and predicted energy
performance. Besides, the tools make it easy for architects to get informative energy analysis. The
accuracy can also be improved through intelligent defaults and assumptions. Thus, one can argue
that the tools are reasonable accurate since the comparisons of the real world and simulations are
almost similar. Besides, the discrepancies in some instances may be associated with the operational
variations. It is reasonably accurate because a skilled modeler can always manage the uncertainties
and variations and ultimately bring about an improved system. However, the aspect of different
modelers raises the question on the scalability of the whole process (Umehara. 2012). Clearly, the
different modelers come with different consistency which influences the accuracy of the tools.
Broadly, the approach is reasonably accurate because the consistent automated range analysis and
automated assumptions define the virtual building. The only limitation of the tool is that it depends
on building performance factors which may influence the measuring aspects. Energy Conservation
Measures have confirmed the effectiveness that comes with these tools.

1.2.2 Energy study of concrete façades is important

From a broader point of view, the energy study of façades is important because it adds on to the
broader field of energy consumption, production, and conservation. Energy study of concrete
façades is an extremely powerful tool in determining the energy consumption of the building. This
information is important as it determines the prospects of saving energy in residential places. Also,
the relative strength of the concrete façades impacts industry profits and industry structure
determines profitability over the long-term. According to the Energy Information Administration’s
(EIA) report titled Annual Energy Outlook 2018, the demand for energy is projected to increase
by 0.5% each year until 2050 (Balocco. 2002). This means that we should study energy
5

performance and consumption of materials like the concrete façades to determine the effective
ways of conserving the energy. To maintain energy levels, it is important to study the energy of
concrete façades. Besides, energy study of façades is an important aspect in determining the
building performance. The information derived from the energy study of façades helps in defining
the necessary input required for the whole building simulation. For instance, the information may
help in establishing the ventilation system (Chin and Gerns. 2012). Depending on the energy levels
of the façade, the information on transport and conditioning of air will be defined. Also, the
information may be used to define the internal gains; for instance, the lighting required.
Information on the energy of these materials is important in indicating the temperature trends, load
profiles, and heat balances. Broadly, it is important to measure the energy levels because the
information derived is of importance in designing the whole building.

1.2.3 Energy simulation is cost-effective

This approach is cost-effective because it only depends on the inputs data which costs nothing.
Other than the economic benefit that comes with this approach, there is also the technical feasibility
of the same. Through the remote process, architects are able to design the building geometry using
the parameters that come with the tools. Based on a cost-benefit analysis, the benefits of the tools
outweigh the small uncertainties that come with the same. The cost-effectiveness comes with the
tools can be clearly seen from the limited amount of materials needed to begin and operate the
machines. Thus, it is right to state that energy simulation is cost effective because it reduces the
additional costs that come with other approaches (Popovic and Arnold. 2000). With limited cash,
the beneficiaries of this project are in a position of getting quick insights. While defining the cost-
efficiency, through some steps, towards a cost-effective intervention (Torgal. 2016). Based on the
background information, the stakeholder perspective in the cost-effective is on the rise. As a cost-
effective approach, there has been avoidance on energy use, new transmissions and cost or benefits
of the approach. The baseline at which the cost and benefits are measured influence the cost.
Umehara (2012) believes that the cost-effectiveness of these tools is not only focused on relative
cost and benefits but also another perspective of the tools. Cost-effectiveness is guided by the fact
that time spent on site construction time.

1.2.4 HEED has been selected as a BEM tool

There are many BEM software tools such as DesignBiulder, eQuest, IESVE and HEED. Each one
of them has some pros and cons. For instance, HEED has the easiest designing models and no need
to export and import by using some other CAD tools to create the models. There are some cons
such as designing the floor area is not flexible as the height because the model should be designed
with a 4x4 feet grid and cannot do curves, free walls, water bodies, green areas in any models,
which are all unnecessary abilities for this thesis project. The author is an expert with HEED since
undergrad and can masters this tool. HEED can show significantly the air conditioning and heating
results, which is only needed, with diverse analyzed 2D and 3D charts, which makes the analysis
more clarified without using other analyses tools.

6

1.3 An Overview of Characteristics of Precast Concrete Façades

Ideally, precast concrete involves a construction product that comes with different characteristics.
When concrete is molded to fit the desired building structure, the precast concrete façades are
formed. This naturally occurring stone helps architects to reduce the expenses that come with the
onsite casting. The strength and durability of the precast concrete façades are reinforced using
steel. This reinforcement brings about comprehensive strength. Concrete fails to have shear
strength and is also subject to poor tension. To account for the challenges that come with concrete,
steel is reinforced. Some of the application of the precast concrete façades includes the
construction of the walls, floors, and foundation. While designing the precast concrete façade,
there exists the need to define the structural components together with the comprehensive and
tensile loads. Since the society advocates for proper maintenance, non-toxic and environmentally
safe, it is important to use this product since it comes with properties. Some of the additional
products that come with precast concrete façades include the meter boxes, hollow-core items, and
telecommunication structures. While defining the overall characteristic of this product, it is
important to mention the thickness of wall panels used. Typically, the thickness of the exterior
precast concrete wall is 20cm (8-inch). The product can be used in virtually all types of buildings.
The flexibility that comes with the material helps the architects, to make decisions on the type of
enclosure to include (Chin and Gerns. 2012). For instance, the product has been able to form
different types of building. Also, this material comes with an aesthetic versatility and energy
efficiency which are of importance in noise attenuation. Besides, it comes with extended
outstanding durability which makes it hard for the mold and rot. The product comes with good
insulation properties which makes it easy for the architect to regulate the temperature of the
building.

1.3.1 What are precast concrete façades?
Precast concrete as a building material was introduced during the post-war period. This
construction material is very popular because of the innumerable options in form, composition,
and surface finish. The introduction of the product was thus important in meeting the economic
advantages and reducing the construction time. This product is currently being made by the off-
site in controlled factory environments (Taylor-Firth. 1991). With time, most of the businesses
have been able to venture into the world of creating the concrete façades. In fact, the product has
undergone transformations geared toward the development of the building industry in general. The
utility structure component of this product helps in an electrical, steam system, gas, and
communication. The product comes with vital control and connections used for controlling the
utility of distributing. Also, there exist the precast concrete transportation products that help in
protecting.

1.3.2 Advantages of precast concrete façades

Broadly, this product comes with a rapid rate of erection which brings about quality control. the
whole building can also take the form of precast concrete façades. Also, there is rapid construction
because of the controlled conditions in the factory. On matters to do with the cost, the product is
efficient because pre-stressing can be easily done. This aspect improves the size and number of
7

structural and architectural members. Data from the Overall Machine Efficiency (OME) portray
the generation misfortunes regarding quality and yield (Clarke. 2007). Precast concrete façades
machine was dissected regarding the availability, execution, and quality. Availability assesses the
limit of the machine to continue running without hardships considering downtime. Execution (P)
evaluates the machine's ability to perform with no speed incidents. Quality relates to the limit of
the machine to convey the standard units without any distortions in quality. Information from the
misfortune examination shows that the machine's execution was well in quality and not execution
or availability. Through the study of energy performance, other parameters which affect the design
and comfortability of the buildings are defined. A good example is the elimination of the
differential thermal expansion problem. This is achieved through the insulation of this product at
the wall section. The study energy performance and consumption of materials like the concrete
façades to determine the effective ways of conserving the energy.

Extensively, the general execution of the machine will be enhanced and moved forward because
the downtime will be diminished (Anderson. 2014). In addition, there will be declined underway
in accidents since the availability and execution of the machine will make strides. This product
helps in reducing the on-site construction time. The many benefits of the product boil down to its
characteristics. The product is aesthetic versatility and energy efficiency. Its sandwiching panels
make it easy for the architects to construct. The knowledge on the energy performance of this
product will help in conserving energy and improving the maintenance costs of the building.
Besides, concrete façades help to minimize energy consumptions as it introduces the architects
and developers to some of the techniques and initiatives like the solar control coupled with cooling
techniques.

1.3.3 Disadvantages of precast concrete façades

The disadvantages of this product include cumbersomeness due to weight and the error margins.
In some way, the product is limited because of the panel size limit. Additionally, the product is
somehow complicated because of the camber in slabs and beams. This makes it hard for the
architects to join between panels. In case of repetition, the product can lead to a change in the
design of the building (Torgal. 2016). Another challenge that the product portrays is the response
that it obtains from individuals who interact with it. Observably, during construction, there are
different perceptions between the participating parties; the employees of a company and the
clients. Regarding this factor, there are emotional obstacles that are present. For example, skilled
personnel are required to lift panels, and the cranes are needed to facilitate lifting of the panels.
These factors may be issues of concern to clients who are not engaged in effective communication.
Finally, precast concrete portrays modification and handling complications. Particularly, the
former is a major disadvantage. Notably, it is difficult to modify a precast structure. For instance,
if a structural wall needs adjustment, the modification process may affect the whole solidity of the
structure.

1.4 The Scope of Research Includes Geometry, Climate

8

Tall thin, cube and short wide model forms are the three dissimilar values in the geometry variable
that were selected for this project. Moreover, climate counts as a second variable, and all these
three models will be tested in three different values (distinct locations), which are Los Angeles,
New York and Las Vegas.

1.4.1 There are many possible geometry variables to examine

One of the main ideas in this thesis is to compare the energy efficiency of different building forms.
Because there are many different building shapes, forms and designs, it has been chosen the most
basic buildings heights in architecture, tall, middle and short. The façade is not tilted, twisted or
angled. To make each one of them have the same massing volume, each one of them has an
adjusted shape size, so the tall model should be thin, the middle must be cubic and the short one
must be wide. Each one has the same aspect ratio, 1:1, square shape to make sure that all three
models are equals. Each model has the same total floor area and massing volume. The scale, total
floor area cannot go more than 1000m
2
with HEED and no need for more because it should be not
a huge precast concrete façade building project. To make all models suitable for the real actuality,
the tall thin model should have almost the smallest possible area in one floor with the stairs and
corridor, which is almost 100m
2
for one residential unit. Total floor area for the tall thin is 1000m
2

÷ 100m
2
for each floor = 10 floor. The standard height for each floor is 3m, means the height for
the tall thin model is 30m, which means the volume equals 3000m
3
(Figure 0.1). Therefore, the
cube and short wide models must be almost the equal volume, 3000m
3
, and total floor area,
1000m
2
, which found after calculating them, cube model has five floors, each floor has two
residential units (Figure 0.2), and short wide model has one floor and all the 10 residential units
are in the ground level (Figure 0.3). Window to Wall Ratio (WWR) is almost 25% because it
should not be 0% which means no natural ventilation and daylighting, and it should not be 50%
because it means the façade will be half glass and half precast concrete, called concrete and glass
façade. Therefore, 25% WWR is a reasonable chosen percentage because it is the average
percentage between 0% and 50%.Windows are square, centralized equally in each floor, vinyl
frame, translucent glass not titled, rotated and angled.

9

(Figure 1.1) Tall thin model.

(Figure 1.2) Medium-medium (cube) model.

10

(Figure 1.3) Short Wide.

1.4.2 Climate is a primary determinate of building façade performance

To make sure that all three models have meaningful results, it should be tested in different climates.
Firstly, America has varied climates more than any region, and it has been chosen because one of
the thesis purposes is to show Americans how precast concrete façade can efficient for building
performance to save energy. Secondly, weather data in the United States is more accurate and
available than any country. The chosen places in the US were selected to be the largest
metropolitan and populations areas like New York and Los Angeles which are development cities.
New York and Los Angeles have different climates which give meaningful results. Chicago,
Dallas, Washington DC, Houston, San Francesco, Philadelphia, Boston, Atlanta, Miami and Las
Vegas are all big cities but most of them have the similar or between New York and Los Angeles
climates. Thus, to add a third place, it is vital be different climate than the chosen two. New York
and Los Angeles are close to a sea that gives moist, so the third place essential be away from the
seas, which makes Las Vegas, one of the prime cities with a desert climate in the US, is the
excellent choice with New York and Los Angeles.

1.5 Summary

Categorically, it is important to study the energy performance of different building shapes and
forms because this insight is important to designers, architects, and clients. Besides, energy study
of façades is an important aspect in determining the building performance. Through the energy
study, concerned personnel will be able to gain knowledge on some of the most important
strategies that can be put into consideration to maximize the efficient use of energy. The
consumption of energy threatens the existence of plants and animals in the world. Clear
observations made on the type of material and its energy requirements are important in helping the
architects and developers to make accurate observations on the building. The insight that comes
with the study helps in making clear observations on the different aspects of the building. On
matters to do with energy simulation, energy simulation is an effective method for analysis because
discrepancies that come between the simulation and results are few. Criteria for assessing the
effectiveness of this method of the analysis show that the approach is effective in measuring the
desired performance and properties of a virtual building. The BEM tools are reasonably accurate
because there are little disparities between the actual and predicted energy performance. Despite
the challenge of this product, the study energy performance and consumption of materials like the
concrete façades to determine the effective ways of conserving the energy. With time, most of the
businesses have been able to venture into the world of creating the concrete façades. Most
businesses have identified the benefit that comes with this product.

11

To sum up, the selected BEM software tool is HEED, and the precast concert is used as a building
material in all three models. There are three different model forms but all of them have a square
shaped floorplan. Tall thin, 10 floors building, 10m x 10m =100m
2
, a residential unit for each
floor, height = 30m each floor 3m. Cube, five floors building, 14.5m x 14.5m = 210m
2
, two
residential unit for each floor, height = 14.5m each floor 3m. Short wide, one floor building, 32m
x 32m = 1000m
2
, 10 residential unit for the only floor, height = 3m. Almost the same volume,
3000m
3
, total floor area, 1000m
2
, and WWR, 25 %. Also, three diverse locations each one in
dissimilar climate, all in the United States, and three supplementary variables, orientation,
infiltration and blinds, each variable has three unlike values.
12

2. EXAMINING PRECAST, MASSING ENERGY, AND CLIMATE-SELECTION

Chapter one was been divided into 5 section heads, the software tool, material, mass, climate and
summery, which are related to the same order in the subtitle of this research thesis. Chapter two is
organized in the same order. The sections heads for the background and literature review chapter
are understanding HEED, applying precast concrete as a façade material, examining the massing
energy efficiency, exploring the locations and summary.

2.1 How Have Others Conducted Similar Studies?

Home Energy Efficient Design (HEED) is one of the free Building Energy Modeling (BEM)
software tools, which uses EnergyPlus Weather (EPW), a free weather data for more than hundreds
and hundreds of sites in the world at the EnergyPlus website. It has been found that US weather
locations are more accurate than others because they provide hourly weather data rather than daily.
This is one of the reasons to select American cities for different models. HEED can show results
about how much any building’s energy and carbon it can generate, as well as, its cost after
modeling and positioning., Moreover, it can give some recommendations to enhance any model or
rousing building. HEED is easy to use, energy tool to design a model, and it does not require an
individual to import and export CAD files to get a model. However, modeling in HEED may not
be flexible while designing a floor because it is a 4x4 feet design. In HEED, designers can only
fill a grid of 4x4 feet as a built area, and they cannot choose the length and width of the model
freely. This may be a disadvantage, but it not affects the research because, in the end, all three
different models must be the same total floor area. The height from floor to floor in HEED is
flexible by inputting any digital numbers, not like the area which should be only filling squares,
4x4 feet, from a grid plan of the HEED molding site. Also, it is easy to create window sizes and
put them anywhere in the external wall. Modifying the building’s design, system and control gives
more opportunities to have accessibilities in building performance. Besides, there are many
advanced detailed designs, systems and controls inputs to integrate and cover all buildings affects.
It shows significant graphics about how the building performance is; for example, 3D charts in the
indoor temperature’s model.

2.1.1 Attia and De Herde did a study of how accurate HEED is

When making a comparison of 10 BEM tools for finding the potential of working and mixing the
tools by building designers during the zero-net energy building design process, HEED is one of
the highest accurate energy software tools. This is after the researchers tested and evaluated 10
software tools including the Open Studio Plug‐in, BEopt, e‐Quest, DesignBuilder, ENERGY‐10,
IES‐VE‐ Ware, Vasari, ECOTECT, Solar Shoebox and HEED. They came up with a conclusion
that HEED is the most accurate after comparing many aspects such as accuracy, interoperability,
usability, process adaptability and intelligence. (Attia & De Herde, 2011).

13

2.1.2 Milne and Liggett did a study of who can use HEED

HEED and Climate Consultant is two energy design tools that are easy-to-use to assist
homeowners, contractors, builders and architects to generate more energy-efficient residential
buildings. These software tools are vital in helping the California State Utilities Commission reach
their goal, which is zero-net energy in all residential buildings by 2020, for new and existing
housing in California. These two tools should be considered before the construction begins. In
other words, they should be the first-day design tool and not to be used by the energy consultants
when the building project is done. Furthermore, these tools work on personal computers and
Macintosh devices and most importantly, they emphasize graphics output. Also, they can match
the building performance of each new plan to show the progress headed for the zero-net energy
(Milne and Liggett. 2013).

2.1.3 Sabunas and Kanapickas did multi scenarios study by using HEED

A study in Kaunas, Lithuania by Sabunas and Kanapickas (2017), aimed to assess the impact of
climate change that is predictable, because of some changes in demand for cooling and heating in
building performance, at an apartment building in Kaunas. Expected temperature data from
Intergovernmental Panel on Climate Change (IPCC) Representative Concentration Pathways
(RCP) 2.6 and RCP 8.5 are run for the phases of the 2020s, 2050s and 2080s, simulated in EPW
Data every hour. By using HEED program to assess the consumptive transformations, the averages
of the climate of over 30-year phase are estimated. Nevertheless, the entire phases and scenarios
have some alterations, since there was a decrease of between 8.5% to 10.3% of total consumption
in the 2020s in the RCP2.6 Scenario to between 26.7% to 29.6%. Moreover, the reduction in the
case of the 2080s in RCP8.5 Scenario, the decrease by 15 %–15.6 % is observed in the RCP8.5
Scenario. The significant decline is due to the dwindling number of needed warm days, though the
minor rise in cooling load at a typical home does not make it prevalent on the heating load.

2.2 Why Precast Concrete was Selected as the Façade Material

The use of precast concrete as a façade material has become quite popular, especially in the 20th
century. It has been used in all types of buildings, from high-rise to low-rise. The load bearing,
façade panels serve various structural and aesthetic purposes. One of the most common ways in
which precast concrete is applied is serving as small panels that are joined to load-bearing
structural frames (Elliott. 2002). The panels made from the concrete come in different shapes and
sizes. There are plenty of options to be explored when it comes to the form, composition as well
as the surface finish for the precast concrete. Some of them are fully kitted with insulation materials
as well as ducts and pipes; all that is left is installation. To quicken the building process, some of
them even come with pre-cut openings for windows and doors (Clarke. 20014). Since the post-war
period, three major types of precast concrete elements used in façades are the cladding,
architectural precast concrete and the popular sandwich panels. Cladding was the first to be
introduced, and the panels were attached as cladding to different load-bearing structures such as
brick walls and concrete masonry. Later, in the 1960s, architectural precast concrete was
introduced. They comprised of a couple of innovations which made it suitable for use business
14

buildings, e.g. offices, residential buildings, e.g. high-rise apartments. In the 1970s, efficient
insulated concrete sandwich channels were introduced. Likewise, they had additional thermal
insulation and aesthetic properties and were used to construct structures quite fast. There are those
precast concrete elements which are strictly decorative, and these include claustrum and decorative
blocks (Lu. 2014).

The precast concrete elements are preferred for use as façade materials due to their combination
of advantages. One of the most significant benefits of using precast concrete as a façade material
is its long-lasting properties, coupled up with shorter construction times. Also, the overall cost of
construction reduces considerably compared to traditional construction techniques.
Correspondingly, there has some level of guarantee in terms of high fabrication standards (Ozlem.
2013). Precast concrete is fast, accurate and clean, and it has a high thermal mass compared to
other façade materials. Also, precast concrete has low material costs, and it found that people in
the Middle East use precast a lot in their building façades.

2.2.1 Precast is a common façade material in the Middle East

Precast concrete has been around pretty much insofar as solid itself. Around 1300 BC,
manufacturers in the Middle East found how to make a hard concrete-like coating by covering
their earth homes with consumed limestone - the antecedent to current bond (Pheng et al. 2012).
About 3 decades after the fact, the Romans had started to blend smashed limestone and other
delicate rocks with sand and water to make an early type of concrete. Emptying this solid into
molds or wooden structures helped shape the mind-boggling water system frameworks and
sepulchers that required exactness of estimation and toughness of development.

Precast concrete is being preferred on the residential growth along the Arabian Gulf region.
Overall, there is an augmented preference for precast concrete arrangements in housing
undertakings as they are believed to be high on durability, low on costs, as well as environmentally
friendly. According to Mitchell (2016), precast concrete is driving novelty or rather creativity in
the real estate industry as architects currently have enormous leverage to advance complicated
designs that can cheaply be generated out the construction site.

Currently, precast is broadly utilized in the development of the superstructure or edge of a building
(Mitchell, 2016). Furthermore, because of its flexibility fit as a fiddle, surface and shading, it’s
regularly utilized as structural cladding intended to copy the presence of additional exorbitant
materials such as limestone, rock or stone. In any case, maybe the best advantage of precast
concrete is that it can fill in as both the auxiliary and compositional component in the meantime,
giving an aggregate precast solid building.

2.2.2 Precast has a high thermal mass

Typically, thermal mass is utilized in the building business to characterize the inalienable property
of a material to ingest thermal vitality; it has nothing to do with protecting materials. A divider
material with high thermal mass can direct everyday temperature varieties. According to Hacker
15

et al. (2008), a great deal of heat energy is needed to change the temperature of high-thickness
materials like precast concrete, and this is the reason concrete has high thermal mass. Wooden
dividers, by examination, are a lot less demanding to thermal with their lower thermal mass. High
thermal mass precast solid dividers act like thermal wipes, engrossing warmth amid the day, and
after that gradually discharging the warmth as temperatures fall around the evening time. In
general, the specific heat of masonry and concrete is assumed to be 0.2 Btu/lb·F.

In fact, precast solid’s thermal mass smoothers out day by day temperature differentials and
subsequently lessens heating and cooling loads on the building’s HVAC framework. The
subsequent vitality reserve funds increase with high swings in surrounding temperature. At the
point when outside temperatures are at their pinnacle, within the building stays cool, because the
warmth has not yet entered the precast solid mass, creating a period slack (Hacker et al. 2008).
Precast gradually discharges thermal into the inside spaces amid late evening and night when
structures are generally unfilled. This deferral in warmth exchange is known as "damping."

Typically, conventional ventilation amid the night can cool down the precast solid's mass, and
afterwards, it can ingest thermal again the following day. The consequence of this deferring or
damping impact is enhanced vitality preservation, which is ordered by the National Energy Policy
Act of 1992 for business structures (Alberdi-Pagola et al. 2018). The thermal mass properties of
precast concrete can likewise help acquire LEED credits. Enhanced vitality execution is only one
of the numerous advantages of precast concrete, yet it is a critical resource for creators who need
to cut warming and cooling costs related with HVAC frameworks and continue building tenants
agreeable.

2.2.3 Precast has low material costs

As far as cost components, an unmistakable preferred standpoint of precast concrete overcast set
up (CIP) is the speed of conveyance and simplicity of establishment or administration. Both
contribute straightforwardly to bring down the total cost of ownership. Precast concrete, mainly
when delivered in guaranteed plants, brags the extra advantage higher quality (Yepes et al. 2015).
Controlled bunch extents set under uniform conditions reliably makes a superior item that can be
thrown set up. For representation purposes, a standard precast underground structure is utilized.
On the building site, booking is a vital, unusual and costly hazard. Nature stacks the cost chances
against CIP concrete. It is a lot faster and less risky decision to have the precast conveyed and
introduced that day as opposed to exhume, frame, pour and strip the CIP solid, fix, soggy
confirmation and refill. For instance, erection of around a 100-square-foot panel can costs around
$30 per square foot, while a 200-square-foot panel can cost about $20 per square foot. This
information generally shows that the cost of using precast concrete is meagre.

On the other hand, precast molds can be utilized many occasions before they are reused and
supplanted. Steel frames used for throwing precast solid parts keep going for significantly a
tremendous amount of time before they are rendered useless. On location, solid development
frames are generally not reused or reused (Marti et al. 2016). Thus, construction firms must
develop a new shape for each venture. Along these lines, utilizing precast concrete is not so much
inefficient but rather more naturally inviting than different choices.
16

On location, solid throwing requires a large workforce, vehicles, and gear. The transportation of
every individual and bit of item to the building site adds costs to the practice. While precast solid
boards require transport when they are done and prepared, the task is much cleaner and more
proficient than the line of blender trucks as are necessary for on location throwing (Marti et al.
2016). Each organization must direct its cost correlation with regards to precisely the amount they
would spare. In this light, fewer work hours and reduced need to transport hardware dependably
make the investment pocket-friendly.

2.2.4 Precast is fast, accurate and clean

Indeed, precast solid molds enable makers to react rapidly to orders for ventures whether they are
expansive or little, intricate or straightforward. Since precasters cast and fix the solid inside a
controlled area, the climate does not influence the creation plan as it does with on-location
concrete. Temporary workers and entrepreneurs alike realize that time postpones lead to lost
dollars. The consistent quality of precast generation and relieving empowers progressively secure
benefits when contrasted with on location ventures (Lei et al. 2015). The organizations ask for the
solid for their task will likewise value the decreased danger of postponements. Like cast set up
concrete, there is a considerable amount of arranging and planning that goes into a precast task.
The task heads must consider the building vision frame a robust procedure before any molds are
made or filled.

Observably, several factors add to the nature of concrete, yet the creation procedure for the precast
concrete surpasses a more significant deal of them than on location throwing. In a precast concrete
plant, the blend is estimated all around the precast concrete mold, and the atmosphere is controlled.
Specialists screen the solid as it's made, cast and restored to guarantee quality (Bihari et al. 2015).
Each solid venture is founded on an assumption, so it is important to discern what extent it keeps
going and how much support it needs. The venture esteem diminishes if the structure starts to
disintegrate before expected. However, the level of speculation increases if the structure endures
longer than foreseen. Precast concrete ordinarily requires less upkeep and has a more drawn out
life cycle. Usually, precast concrete should be maintained at a temperature which is slightly above
40° degrees Fahrenheit.

Finally, precast development maintains the site cleaner and eliminates trades from the development
zone, enhancing coordination and upgrading laborer security. Site storage is typically not needed,
segments of precast are lifted by a crane specifically from the truck into place in a construction
(Lei et al. 2015). A perfect or somewhat clean site is especially imperative on constructing
additions and open grounds and in impenetrable metropolitan locations, where the adjoining
construction can keep up close usual undertakings.

2.3 Massing Energy Efficiency

The different masses expose various EUIs. For instance, in South Korea, researches and surveys
have revealed that residential tower type (tall mass) consumed more energy and emitted more
17

carbon than residential plate type (wide mass) by analyzing electricity and gas consumption. The
results show tower type consumed 48% more electricity than plate type, but they show tower type
consumed 10% less gas than plate type buildings (Choi et al. 2012). However, tall buildings give
a significant chance for saving energy according to another research (Elotefy et al., 2015), but the
comparison has been done between the tall, super tall and mega tall masses in some existing
buildings in different sites, volumes, and designs, which have no independent variables (Figure
2.1).

(Figure. 2.1) Tested tall buildings. (Elotefy, 2015).

2.3.1 Why is massing energy efficiency the key concept for performance?

Mathematical modules have been done to demonstrate how building density affects energy-
efficiency. It shows that probabilities of building density can improve the energy-efficiency up to
20%. The design variable is the ratio of surfaces area to building volume. The efficiency of massing
buildings depends both on its scale and properties (Parasonis et al. 2012). If they made the
buildings size, volume, equal, it could be concentrated what the properties in more details are. In
Portugal, De Castro and Gadi tested the building orientation in five site slopes between ±0° to -
50° by using EnergyPlus simulation tool. They have noticed the -30° of building orientation is
lowering the monthly average load and annual energy consumption if the building is a box type
design (De Castro and Gadi. 2017).

18

2.3.2 What other metrics were considered?

Another research found that WWR is the most significant variable in the life cycle environmental
impact a building after comparing it with two other variables, orientation and glass type, in many
different values (Su and Zhang, 2010). WWR is set up as a constant variable in this thesis to make
sure there will be no life cycle environmental impact between the different masses.

2.4 Three Locations are Chosen for Conducting Simulations

The climate in these three various cities must be shown by the weather data and studies and how
they benefit this research. If the thermal comfort has been set up between 21-24 °C (70-75°F),
some buildings in particular cites will give better energy-efficient due to the outside temperature
because it affects the indoor temperature, relatively.

2.4.1 Los Angeles is a mild climate

The variety of building designs in the U.S. is dependent on the building material available and the
natural environment. Notably, climate and weather are phases of the natural environment. In the
same way that climate varies across different parts of the United States, so does the buildings and
the architectural designs (Palmer. 1917). For example, the weather and climate in Los Angeles
are linked to the conditions in the State of California in general. In Los Angeles County, located
in the southwest area of the state, the observation is that there is a moderate climate. The hottest
month sustains an average temperature of 84.8°F, and the coldest has an average of 48.3°F (Reed.
2015). These months are August and December respectively. Climatic attributes have an impact
on how buildings are constructed. For example, in the northern part of the U.S., the sleeping porch
can be used with comfort during summer time only. In the other parts, it can be used all year round.
In Los Angeles, Palmer states that it is difficult to rent or sell a residence that does not have at least
one sleeping porch (Miller. 2017). Generally, the geographical location of Los Angeles is the main
reason for the temperate climate. The proximity to the Pacific coast implies that the summer period
is cooler than in other places. Also, since the city is located at a latitude lower than the
Mediterranean coasts, the winters are also mild (Miller. 2017). The presence of Arizona and
California deserts in the State of California implies that rainfall is an infrequent occurrence in Los
Angeles, and the annual level is 375mm, which is similar to the Mediterranean climate.

2.4.2 New York is cold climate

The climate of New York is relatively and temperate. It is described as continental since there are
relatively hot summers and cold winters. The city is situated on the coastal region, on the edge of
a continent that has a regular weather pattern of cooling down during winter and heating up
considerably during the summer season (Karl, 2009). The instability in the climate can be
attributed to the fact that the region serves as a collision point for air masses hailing from different
regions. The coldest month is January and temperatures average 0.5 °C, and it can go as high as
24.5 °C in July which is the warmest month. The precipitation levels are constant throughout the
19

year (Bhargava, 2017). New York City has a couple of advantages and challenges owing to its
landscape properties. Some of the undesirable events that the metropolitan city could experience
include heat waves, massive rains and coastal flooding due to the average sea level rise. Hurricane
Sandy opened up the eyes of New York residents since it caused so much harm, beyond what they
imagined. It became quite clear that the city was quite vulnerable especially in the face of extreme
climate events (Rosenzweig & Wolfe, 2011). In as much as the climate is relatively calm at most
times, the city is slowly investing in preparation for higher seas in anticipation for extreme events
that come with future climate changes. All city stakeholders and planners involved should be better
equipped for the sake of climate action planning. This includes regularly updating the city climate
projections as well as the associated urban change action plans. One of the proactive measures that
have been adopted to mitigate extreme events of climate and weather is directing resources towards
resilience. These include putting in place citywide policies, for example, putting more emphasis
on green infrastructure such as green roofs and upgrading certain aspects of building codes (Mills
& Cleugh, 2010).

2.4.3 Las Vegas is hot and dry climate

Located in the arid State of Nevada, the weather and the climate are similar to the characteristics
of a desert. Thus, the summers are scorching, and the winters are mild. The annual rainfall is only
100mm, which implies scarcity (Vaca, 2015). Generally, the weather patterns are considered harsh,
and there are careful considerations when designing homes and buildings. Early in the design
process, fundamental factors such as energy efficiency are enforced through the precise formation
of the building's orientation.

Wang et al. (2018), state that temperatures in the city area skyrocket during the summer because
it is located in the middle of the desert. This happens between May and September. In this season,
temperatures can exceed 115°F. On the other hand, during winter, which lasts from November to
March, temperatures can drop to the freezing point. However, the lowest ever recorded is 20°F
(Gorelow, 2005). There are vital things to note about the desert climate. One of them is prolonged
summer days that cause prolonged heat exposure (Kamal et al., 2015). For instance, in 2014, the
longest day during the summer is 5:23 AM to 8:01 PM. These are 14 hours and 37 minutes of
exposure to heat. In this area of the Southwestern United States, the moderate climate is hot and
subtropical (Wang et al., 2018). Las Vegas is in a basin on the floor of the Mojave Desert, and July
is the warmest month. Also, the sunshine in the city is all year round, with the skies always clear.
With more than 3800 hours of sunshine annually, Las Vegas is one of the sunniest cities in the
world. Regarding the wind, Gorelow cites that the direction of the wind varies throughout the year.
Typically, the speeds range from 1 to 18 mph.

2.4.4 Why these three are appropriate selections

Firstly, America has varied climates more than any region, and it has been chosen because one of
the thesis purposes is to show the Americans how precast concrete façade is efficient for building
performance to save energy. Secondly, whether data in the United States is more accurate and
available than any country. The chosen places in the US should be the largest metropolitan and
20

population like Los Angeles and New York which are development cities. Los Angeles and New
York have different climates which give meaningful results. Chicago, Dallas, Washington DC,
Houston, San Francesco, Philadelphia, Boston, Atlanta, Miami and Las Vegas are all big cities,
but most of them have the similar or between Los Angeles and New York climates. Thus, to add
a third place, it vital be different climate than the chosen two. Los Angeles and New York are close
to a sea that gives moist, so the third place essential be away from the seas, which makes Las
Vegas, one of the prime cities with a desert climate in the US, is the excellent choice with Los
Angeles and New York.

2.5 Summary

All in all, these studies show how many kinds of research and reports have been done by scholars
about building form and its energy-efficiency. Some of them used HEED, and some tested the
precast concrete as a façade material. Also, it has reviewed some case studies in this chapter like
investigating how different masses affect the building performance and describing how the climate
in three selected cities look like and how it affects their inside buildings. It has revealed numerous
ideas such as setting up the precast concrete wall thickness, 20cm (8’’), using almost the same
massing volume, 3000m
3
, total floor area, 1000m
2
, plan aspect ratio, 1:1, WWR, 25%. All other
variables like glass, window frame, lightings, cooling and heating systems are selected according
to the US energy building codes and standards. Building materials are all precast concrete, and all
three models have the same most straightforward slab on grade foundation systems and flat plate
structural and roofing systems. There are no renewable energy techniques, water management,
overhangs, shades, skylights, balconies, courtyards, surroundings like landscape and buildings,
interior designs which may affect the building energy performance like colors and interior walls.
All other specifications are the same and standard in the three different models as a constant
variable to make sure that the comparison between the models is fair and equal.
21

3. METHODOLOGY

There are three different masses and climates to support which building shape is the most efficient.
These are the main two variables with three diverse values in each one. In addition, there are three
variables have been chosen, which are orientation, infiltration and blinds.

Each of these affects any massing performance through design, system, and control. In regards to
the first variable, the values of the orientation variable are ±0°, -30° and -45° slopes. Second, the
values of the infiltration variable are Sealed HVAC Ducts + Building Air Barrier, 2.0 SLA/ 4.0
ACH, Verified Air Sealed + Quality Insulation Installation, 1.5 SLA/ 3.0 ACH, and Passive House
Standard, 0.3 SLA/ 0.6 ACH. Lastly, the values of the Light Venetian Blinds variable are fixed
mode, at -45°, closed mode, when the sun is on the window and indoors is above comfort low, or
3°F below comfort high in winter, and last mode is automated with temperature, at -45° or closed
tight hourly when the indoor temperature reaches 3°F below comfort high. A value of one of these
three addition variables should be only in one scenario. For example, in a tall thin mass in Los
Angeles climate with oriented building in -45° slope is one scenario, and all other details and
specifications standardized according to the US building codes like 13.0 SEER, 78% AFUR and
2.5 SLA/ 5.0 ACH for infiltration or default if there are no standards for them like orientation
which is set to ±0°. Another example is a short wide mass in New York climate with Verified Air
Sealed + Quality Insulation Installation, 1.5 SLA/ 3.0 ACH for the infiltration system, with all the
other details and specifications similar with the first scenario.

3.1 Schematic Diagram of Methodology

(Figure 3.1) Methodology Diagram. (in the +Variables level of the methodology diagram there are
some abbreviations such as D which means the Designing variable, the orientation values. Also, S
which is the System variable, the infiltration values, C means the Control variable, the Light
Venetian Blinds values, and N means No Heating and Colling for each model see {Figure 3.2}).
22

3.2 Branching Scenarios

(Figure 3.2) Scenarios.

3.3 Three Basic Massing Schemes are Selected

It has been chosen to test three different masses that altogether exhibit small sizes and square plans.
Specifically, all masses should use dissimilar forms like tall, thin, medium-medium and short wide
but almost the same volume of 3000m
3
, a total floor area of 1000m
2
, plan aspect ratio of 1:1, WWR
of 25%, and precast concrete façade, 20cm (8’’) thick, with U value of 0. 07, light color, with a
rigid foam board R13 continuous. However, the total floor area is not flexible like floor to floor
height because Home Energy Efficient Design (HEED) can only do 1.22m×1.22m (4ft×4ft), length
and width, and the design on each floor. Therefore, the chosen numbers for volume and area should
be tweaked. Thus, 4×4 feet equal 16sqft which equals 1.49m
2
.

3.3.1 Tall thin massing

The total site area of tall thin mass is 100m
2
, and 100m
2
÷ 1.49m
2
= 67.11 squares of 4×4 feet —
furthermore, 67 squares of 4×4 feet equal to 99.83m
2
. However, to make sure this massing has a
square plan, it must have 64 squares. Thus, the length and width are 8×8 squares, implying
95.36m
2
. This is the closest area can be done in HEED to what has been chosen; 100m
2
. Tall, thin
mass has 10 floors, denoting that the total floor area is 95.36m
2
× 10 floors = 953.6m
2
× 3m floor
to floor height = 2860.8m
3
. Therefore, the surface area to volume ratio at this model is,
95.36m
2
:2860.8m
3
, which translates 0.033m
-1
.

3.3.2 Medium-medium massing

The total site area of medium-medium mass is 200m
2
. 200m
2
÷ 1.49m
2
= 134.23 squares of 4×4
feet and 134 squares of the 4×4 feet equal 199.66m
2
. However, to make sure this massing has a
23

square plan, it must have 144 squares. Thus, the length and width are 12×12 squares, inferring to
214.05m
2
. This is the closest area can be done in HEED to what has been chosen, which is 200m
2
.
Medium-medium mass has five floors, meaning that the total floor area is 214.05m
2
× 5 floors =
1070.25m
2
× 3m floor to floor height = 3210.75m
3
. Therefore, the surface area to volume ratio at
this model is, 214.05m
2
:3210.75m
3
, which translates to 0.066m
-1
.

3.3.3 Short wide massing

The total site area, also referred to as the total floor area because there is only one floor for this
mass, of short wide mass is 1000 m
2
. Correspondingly, 1000m
2
÷ 1.49m
2
=671.14 squares of 4×4
feet and 671 squares of 4×4 feet equal 999.79 m
2
. However, to make sure this massing has a square
plan, it must have 676 squares. Thus, the length and width are 25×25 squares, resulting in 1007.24
m
2
. This is the closest area can be done in HEED to what has been chosen; 1000m
2
. 1007.24 m
2
×
3m floor to floor height = 3021.72 m
3
. Therefore, the surface area to volume ratio at this model is
1007.24m
2
:3021.72m
3
, resulting in 0.333m
-1
.

3.3.4 Why these three were selected

There are many different building shapes, forms and designs. Therefore, to make the comparison
unbiased, all the three different models should have the same floor plan shape. Also, it has been
chosen as the most basic building heights in architecture, tall, medium and short. To ensure
similarity in volume, each one of them should have the opposite shape size, so the tall model
should be thin, the medium model in precisely the shape of a cube, and short model should be
wide. Each one has the same aspect ratio of 1:1, attributed to the square shape that ensures that all
three models are equal. In this light, each model has nearly the same total floor area and massing
volume. The total floor area cannot exceed 1500m
2
with HEED, and there is no need for the excess
area because it should be not a huge precast concrete façade building project. To make all models
suitable for the practical reality, the tall thin model should have almost the smallest possible area
on one floor with the stairs and corridor, which is almost 100m
2
for one residential unit. Thus, the
total floor area for the tall thin model should be 1000m
2
÷ 100m
2
for each floor, to give a total of
10 floors. That makes medium-medium massing to have five floors, and short wide massing to
have only one floor.

3.4 Three Different Locations are Selected

These massing models should be tested in different climates to provide accurate results. For this
reason, Los Angeles, New York and Las Vegas are the three selected locations. Notably, all of
them are developed cities and located in the US, but they have different varying climate conditions.
In addition, each one has a different landscape and weather. HEED uses EnergyPlus Weather
(EPW), which is a free weather data program for more than hundreds and hundreds of cities in the
world at the EnergyPlus website. From the program, it is found that the US weather locations are
more accurate than others because they entail hourly weather data rather than daily weather data
as observed in cities outside the US. This is the primary reason that supports the selection of
American cities for these different models.
24

3.4.1 Los Angeles

The psychrometric chart below describes the hours of thermal comfort zones in the range of 21°C
to 24°C (70°F to 75°F) that are throughout the year in Los Angeles. It is essential to show this
information because some locations have lower energy consumption or Energy Use Intensity due
to the weather impacts on the buildings. Thus, Los Angles has 520 hours of thermal comfort, which
translates to 5.9% out of the 8760 hours. The other hours are extremely close around the thermal
comfort zone in blue, and most of them are chiller and more humid than the thermal comfort zone
(Figure 3.3).

(Figure 3.3) Psychrometric chart of Los Angeles. (Climate Consultant software tool)

25

3.4.2 New York

In New York, the thermal comfort hours are not very different from than Los Angles because it
has 492 hours in the thermal comfort zone (Figure 3.4). All other hours are not near to the thermal
comfort zone, and most of them are humid and enormously cold.

(Figure 3.4) Psychrometric chart of New York. (Climate Consultant software tool)

26

3.4.3 Las Vegas

Observably, Las Vegas is different from Los Angles and New York because it is scorched and hot.
The hours of the thermal comfort are 371in a year. Therefore, it translates to 4.2% of thermal
comfort which makes Las Vegas an awful city to achieve the best energy-efficiency due to the
need of cooling and moisturizing because most of the hours which are outside the thermal comfort
zone are extremely dry and incredibly hot (Figure 3.5).

(Figure 3.5) Psychrometric char of Las Vegas. (Climate Consultant software tool)

3.5 Assembling and Examining the Results

After completing all the scenarios, which are 81 scenarios, the indoor temperature and EUI can be
collected easily and presented through charts and tables that are provided after simulating each
scenario in HEED. The total energy consumption, total heating, and cooling HVAC output, heat
loss and hours when no cooling and heating needed are not taken up because the total floor area
and massing volume are not even, so it may not give accurate results between different masses.
Next, the subsequent step is comparing each scenario’s results by computing the EUI. A lower
EUI number means more massing energy efficient. Also, all the indoor temperature 3D charts can
be compared together to see how much each one saves energy to prove how the precast concrete
façade is significant, and how it saves energy in the United States.

27

3.6 Summary

Calculating the different masses, which are tall thin, medium-medium and short wide models, to
have the same massing volumes, total floor area, plan aspect ratio and WWR proves easy.
However, modeling, the first level of the thesis simulations through the chosen three building
forms is not easy because there is a struggle, which is the 4x4 feet scheming in HEED, so the
masses cannot have the exact same massing volume and total floor area. The limitation that comes
into context is that HEED can only model 4x4 feet squares, length and width, design in each floor
by filling this square grid (Figure 3.6).

(Figure 3.6) Floor Planner screen (HEED)

Thus, the total floor area, 1000m
2
, and massing volume, 3000m
3
, of the three different masses
have changed to the nearest areas and volumes that HEED can design with its square grid. The tall
thin model’s total floor area is 953.6m
2
, the massing volume is 2860.8m
3
, and the surface area to
volume ratio is 0.033m
-1
. The medium-medium model’s total floor area is 1070.25m
2
, with a
massing volume of 3210.75m
3
, and the surface area to volume ratio is 0.066m
-1
. The short wide
model’s total floor area is 1007.24m
2
, the massing volume is 3021.72m
3
, and the surface area to
volume ratio is 0.333m
-1
. Siting the models, the second level of the thesis simulations, has no
issues with HEED because it uses EPW, and the nominated sites are Los Angeles, New York, and
Las Vegas. Selecting the additional variables, the third level of the thesis simulations, orientation,
infiltration, and Light Venetian Blinds also has no issues with HEED. Notably, ±0°, -30° and -45°
slopes are the values of the orientation variables. In addition, sealed HVAC Ducts + Building Air
28

Barrier, 2.0 SLA/ 4.0 ACH, HERS, Verified Air Sealed + Quality Insulation Installation, 1.5 SLA/
3.0 ACH, and Passive House Standard, 0.3 SLA/ 0.6 ACH are the values of the infiltration variable.
In regard to Light Venetian Blinds variable, fixed mode, at -45°, closed mode, when sun is on
window and indoors is above comfort low or 3°F below comfort high in winter, and automated
mode with temperature, at -45° or closed tight hourly when indoor temperature reaches 3°F below
comfort high emerge. Only one value of these additional variables should be chosen for each
scenario. The scenarios are simulated by using HEED, and it takes about 2-3 minutes to show the
results of one scenario. If something wrong is in the results, the input should be rechecked ; in a
manner similar to the scenario of missing data. Moreover, there is a need to simulate the scenario
again until it shows accurate results. Afterward, it is crucial to collect all the indoor temperature
and EUI results in each scenario and putting them in a table to make the analyses easier to observe.
Lastly, the process should entail analyzing the compared results of all scenarios by proposing some
conclusions, for example; which mass wins and investigate if the hypotheses are right or false.
29

4. DATA AND RESULTS

This chapter aims at describing each step of inputting data in HEED, and it illustrates how HEED
knows about concrete and many other building details such as designing the building form and its
windows. Also, it confirms how the results come out after simulating each model in its different
scenario. There are three models, and each model has 27 scenarios. Therefore, there is a total of
81 scenarios, and each scenario gives different outputs.

4.1 Inputs

At first, HEED points out how the building works by providing insight into the design components
(Figure 4.1). It addresses this aspect by asking questions such as what kind of building it is, what
the total floor area is, what type of roof it has, and how many the stories there are. By doing this,
HEED is automatically creating two reference schemes that meet the California Energy Code and
More Energy Efficient, which are in accordance with the answers of these questions by using
default design. However, these two schemes should not be considered because the primary
comparison is between the three models: tall thin, medium- medium and short wide, each in a
different location and unique variables.

(Figure 4.1) The Starting up process.

30

4.1.1 First common steps for all models

Firstly, some questions should be answered like what this building would be; either a constructed
new building, remodeled within existing walls, or added on the outside of an existing building
(Figure 4.2). The answer would be the first option; constructing a brand-new home because this is
what had been selected earlier. Secondly, it is important to answer the question about what kind
of home it will be. If the townhouse or the apartment are taken, the next question will be inquiring
about the neighbors on matters such as if there are units below or above the tested model.
Moreover, it is essential to ask if there are units that share the same wall with the model. Therefore,
the single-family house is the chosen one because there will be no questions about neighbors as it
has been illustrated previously. Thirdly, it is a part of the process to investigate how many stories
that this model has. Observably, the answer is ten stories for the tall thin model, five stories for the
medium- medium model and one story for the short wide building. Forth, the question regarding
the size of the building which means the total floor area, reveals that it is 1000 m
2
(10763 square
feet) for all the models. However, this will change a little bit due to the strict designing
accessibility, 4x4 feet, and the plan aspect ratio of 1:1 requirement. Next, there is the question
about the roof shape. The answer is a flat shape because it will make the comparison between the
three different models fair and equal.

Last but not least, what is the location? In regard to this question, there are 27 scenarios for the tall
thin model. Los Angeles represents nine different scenarios for the tall thin model, New York, also
has nine scenarios, and then Las Vegas has nine scenarios.

(Figure 4.2) Initial Design for tall thin model.

31

(Figure 4.3) Reference home that Meets the US Building Energy Code and More Energy Efficient
for tall thin model.

HEED presents two schemes, which are Meets Energy Code and More Energy Efficient as the
references to this size and kind of buildings. The first two schemes cannot be modified, but the
new scheme, the third one, is adjustable. Thus, the next step is revealing the bar chart for the first
two schemes. Also, it shows some other tiers like 15%, 30% and 50% that are better than the
Energy Code Minimums (Figure 4.3). Moreover, it shows that if this model exceeds Zero Net
Energy and Net Energy Producing Home, it generates 20% more energy than it uses.
32

(Figure 4.4) Creating third scheme by copping from the second scheme to modify.

Next, HEED shows the third screen of the tall thin model, and the third scheme can be modified
after this screen. Automatically, HEED is creating the third scheme by copying the second scheme.
The name of the third scheme is Default/ Standard/ Minimum requirements. This name is based
on the fact that the third scheme will be not tested for attributes linked to the redesigned model,
and to what has been selected for the tall thin model like what kind of façade is, what the WWR
is, and much more. After redesigning the third scheme, the fourth scheme will be tested in a similar
fashion to the first scenario. In (Figure 1), it displays a bar chart of all the three schemes and gives
the data about electricity and fuel that have been used in components like air conditioner, fans,
lights, heat, appliance fuel, water heater, etc. (Figure 4.4).

33

4.1.2 Tall thin model steps

Floor Planner is the next step in this software tool, and it demonstrates how the model is designed
for the first two schemes (Figure 4.6). However, in the third scheme, the model can be redesigned.
For example, in the Floor Planner, HEED designed the floor plan for the tall thin model by almost
11×5 squares. According to the designated dimensions for the tall thin model, the plan for the tall
thin model should be 88 squares (Figure 4.7). It is clear that all the three models must have the
same plan aspect ratio of 1:1, implying square plans. After redesigning each floor of the tall thin
model (Figure 4.8), HEED goes to the next step.

(Figure 4.6) Automated floor design from HEED for the first two schemes.

34

(Figure 4.7) Redesigning each floor of the tall thin model.

(Figure 4.8) Remodeling the tall thin mass.
35

(Figure 4.9) North orientation of the tall thin model.

The orientation is the next step. Observably, the orientation of the three models is to the north
(Figure 4.9). However, it does not matter if the buildings are oriented to the south, east or west
because it is the same orientation because the models have identical square plans. However, in the
next steps, there are three different scenarios in each model that have unalike orientation values:
±0°, -30° and -45° slopes. These slopes rotate from the top to the right, clockwise rotation, of these
models.
36

(Figure 4.10) Window design screen of the tall thin model before editing.

From the screen of the window, door, and sunshades designs, it has been determined that there are
no sunshades, overhangs, and fins for all the three models, implying that they should be deleted
(Figure 4.10). In the design, the current window designs for the tall thin model are designed by
HEED, automatically. Similar to the windows, all the three models have the same WWR, 25%,
and the window aspect ratio of 1:1 equally on each floor.

37

(Figure 4.11) Window design screen of the tall thin model after editing.

Therefore, all windows on each side of the models should be of the same quantity, and the window
sizes should be almost the same in every different model. It has been chosen that the window width
and height are about 1.22m ×1.22m (4×4 feet) because the edge conditions of the windows will be
not having the same dimensions if the dimensions are shorter or longer than the chosen width and
height dimensions. Hence, the window area should be approximately the same, 1.49m
2
(16 square
feet), to make the WWR equal to 25% for the tall thin model. The window’s width and height are
1.20m × 1.20m (3.92×3.92 feet), so the window’s surface of the tall thin model is 1.43 m
2
(15.37
square feet). The window quantity for the tall thin model must be 50 windows in each side(Figure
4.11), 200 windows in total, so the WWR of the tall thin model is 25%. The window size and
quantity of the other two models, medium-medium and short wide, are described in the succeeding
subsections.

38

(Figure 4.12) Window Layout screen during placing the windows.

The next screen is about the window layout; the windows must be centralized and balanced equally
at each façade of a model, as is clear that the space between each window from another is equal
(Figure 4.12). If the window sizes are longer or shorter, the spaces between the windows will be
tighter or further respectively. Therefore, the selected window size is the most practical and
balanced for all different three models. HEED cannot offer the user an easy and accurate way to
configure all windows at once, so each window should be dragged to the place that the user
requires.
39

(Figure 4.13) Window Layout screen in the tall thin model after placing the windows.

After placing all the windows on the four sides of the tall thin model, this is how it looks like as it
is seen in the conceptual design(Figure 4.13). It is challenging to drag 200 windows and make sure
that they have the same different spacing because there are no options to help the user to make it
smoother and more accurate.

40

4.1.3 Medium-medium model steps

The Floor Planner screen in the medium-medium model displays the designated dimensions for
the medium-medium model; the plan for the medium-medium model should be 12x12 squares. It
has indicated that all the three models must have the same plan aspect ratio of 1:1 in a square plan.
Next, HEED attempts to proceed to the next step after redesigning each floor of the tall thin
model(Figure 4.14).

(Figure 4.14) Remodeling the medium-medium mass.

41

(Figure 4.15) Window design screen of the medium-medium model after editing.

All windows on each side of a model should have the same quantity and window size, and the
window sizes should be almost the same in every different model. It has been chosen that the
window’s width and height are about 1.22m ×1.22m (4×4 feet) because the edge condition of the
windows of not having the same dimensions, especially if these dimensions are shorter or longer
than the chosen width and height dimensions. Hence, the window’s area should be around the
same, 1.49m
2
(16 square feet), to make the WWR equal to 25% for the medium-medium model.
The window width and height are 1.24m × 1.24m (4.06×4.06 feet), so the window’s surface area
of the tall thin model is 1.54 m
2
(16.58 square feet). In addition, the number of windows of the
medium-medium model must be 35 windows on each side(Figure 4.15); 140 windows in total, so
the WWR of the tall thin model is 25%. The window size and quantity of the short wide model are
described in the next subsection.
42

(Figure 4.16) Window Layout screen in the medium-medium model after placing the windows.

The windows must be centralized and balanced equally at each façade of a model, and the space
between two windows should also be equal. If the window sizes are longer or shorter, the spaces
between the windows will be tighter or further. Therefore, the selected window size is the most
stable and balanced for all different three models. HEED cannot offer the user an easy and accurate
way to configure all windows once; therefore, each window should be dragged to the place that
the user requires. Placing all the windows in the four sides of the medium-medium model portrays
how the configuration of the windows is likely to take place(Figure 4.16). Unarguably, it is not
easy to drag 140 windows and make sure that they have the same different spacing because there
are no options to help the user to make the process smoother or more accurate.

43

4.1.4 Short wide model steps

The Floor Planner screen in the short wide model presents the elected dimensions for the short
wide model; the plan for the short wide model should be 25×25 squares. It is indicated that all the
three models must have the same plan aspect ratio of 1:1 in square plans. HEED advances to the
next step after redesigning each floor of the tall thin model. The short wide model shows why it
cannot elect bigger one-story building because the max area in HEED is 30×30 squares, thus
resulting to 1,337 m
2
(14,400 square feet), so the 25×25 squares, which equals 10,000 square feet
squares, have been chosen(Figure 4.17). Another reason for their selection is because it makes the
calculation faster and easier even for any slightly larger scales tests in the future work to compare
between different area scales of HEED models.

(Figure 4.17) Remodeling the short wide mass.

44

(Figure 4.18) Window design screen of the short wide model after editing.

As aforementioned, all windows on each side of the model should exhibit the same quantity and
window size. It has been chosen that the window width and height are about 1.22m ×1.22m (4×4
feet) because the edge condition of the windows will be not having the same dimensions if these
dimensions are shorter or longer than the chosen width and height dimensions. Hence, the window
area should be around the same, 1.49m
2
(16 square feet), to make the WWR equal to 25% for the
short wide model. The window width and height are 1.22m × 1.22m (4.00×4.00 feet), so the
window surface of the tall thin model is 1.49 m
2
(16 square feet) (Figure 4.18). The window
quantity of the short wide model must be 15 windows in each side, resulting in a total of 60
windows, so the WWR of the tall thin model is 25%. Most importantly,
45

(Figure 4.19) Window Layout screen in the short wide model after placing the windows.

the windows must be centralized and balanced equally at each façade of the model, and the space
between each window from another should be equal. If the window sizes are longer or shorter, the
spaces between the windows will be tighter or further. Therefore, the selected window size is the
most effective and practical for all different three models. It is above-mentioned that HEED cannot
offer the user an easy and accurate way to configure all windows once, and each window should
be dragged to the place that the user requires. Placing all the windows on the four sides of the short
wide model gives the following outcome as seen in the screen(Figure 4.19).

46

4.1.5 Last common steps for all models

Next, there is the consideration of the glass type screen, which asks two questions. First, it asks
what type of window framing is used, and second, what type of glass is chosen(Figure 4.20).
According to the building codes of the selected cities, Los Angeles, CA, New York, NY, and Las
Vegas, NV, the selection process landed on the “wood, vinyl, or fiberglass, operable windows”
option. Based on the residential prescriptive window requirements in the 2018 International
Energy Conservation Codes (IECC), there are eight different climate zones in every US county,
where Los Angeles County in climate zone number three, New York county in climate zone
number four, and Las Vegas county in climate zone number three(Figure 4.21). All the three places
have the same requirements in the window U-factor, which is ≤ 0.32, but a different Window
SHGC, which is ≤ 0.25 for Los Angeles and Las Vegas and ≤ 0.40 for New York (Table 4.0)
(Efficient Windows Collaborative. 2018). Also, there are more diverse requirements regarding the
skylights, but it is not a central issue because it has been decided before that there are no skylights
for all the three different models. As a result, the “Clear Argon filled Double Pane Low-E Squared
in Insulated Vinyl frame, U=0.30 and SHGC=0.25” has been selected for the preferred glass type.

(Figure 4.20) Glass type screen

47

(Figure 4.21) The US climate zone map of the IECC.

(Table 4.0) Residential prescriptive window requirements in the 2018 IECC.

Climate Zone Window U-factor Window SHGC Skylight U-
factor
Skylight
SHGC*
1 No Requirement ≤0.25 ≤0.75 ≤0.25
2 ≤0.40 ≤0.25 ≤0.65 ≤0.25
3 ≤0.32 ≤0.25 ≤0.55 ≤0.25
4 except Marine ≤0.32 ≤0.40 ≤0.55 ≤0.40
5 & Marine 4 ≤0.30 No Requirement ≤0.55 No
Requirement
6 ≤0.30 No Requirement ≤0.55 No
Requirement
7 & 8 ≤0.30 No Requirement ≤0.55 No
Requirement
*Skylights may be excluded from glazed fenestration SHGC requirements in zones 1-3 where
the SHGC for such skylights does not exceed 0.30.
48

(Figure 4.22) Insulation screen.

The insulation screen entails what kind of insulation system and code are used in all the three
models (Figure 4.22). Firstly, “High Mass Wall with Interior Insulation” is the system code for
these models due to the chosen façade material, which is precast concrete with interior insulation
because it reduces the unhealthy impact risks associated with indoor exposed concrete to the
human health, as it is observed from some previous researches in chapter two. Secondly, “No
Radiant Barrier in the Attic” has been selected because there is no vented air space above insulation
as it designed in all the three models.

49

(Figure 4.23) Walls screen.

The “Exterior Finish on 8’’ (20cm) Concrete Block, 2×4 Wood Studs at 16’’ (40cm) with R13
Cavity insulation, Gypsum Board” has been chosen as an envelope material because it is the only
precast concrete with insulation on the interior (Figure 4.23). Also, it has the lowest U-factor in
HEED, which is 0.07, and it can meet any building and energy codes in any state because it is
below than any state code in the US. The exterior finish implies stucco on the concrete block, and
R13 Cavity insulation means 4’’ (10cm) fiberglass. To test the three different model forms, they
should be built and designed with the available and best building materials and systems in the US,
or at least they should meet the highest state codes.
50

(Figure 4.24) Roof screen.

After the completion of the exterior building wall, the roof screen comes out with one question;
what kind of roof construction is it? In one of the picked locations in Los Angeles, CA, under Title
24 of Building Energy Efficiency Standers, cool roofs became a requirement in 2005. Also,
because all the three different models have been designed with a flat roof, “cool roof, flat or low
slope”, must be selected from all the options in this screen. Also, all the roofs have gypsum board
ceilings and wood joists with insulations in between (Figure 4.24).
51

(Figure 4.25) Floors screen.

It has been chosen that floor construction is concrete. However, on the floor’s screen (Figure 4.25),
two options have the same material. These options are “Concrete Structural Floor, Exposed or
Tiled, above grade” and “Concrete Structural Floor, Carpeted, above grade”. The latter is more
complicated because if the model is carpeted, it must insert a percentage of how much is it carpeted
on another screen, which has not discussed before. Therefore, the “Exposed or Tiled above grade”
is the preferable selection. The second question is about the condition of under the first floor, which
“Earth under Slab” option has been chosen.
52

(Figure 4.26) Infiltration screen.

One of the most critical screens is the infiltration screen because the “DEFAULT STANDARD
DESIGN: sealed HVAC + building air barrier, 2.5 Specific Leakage Area (SLA), 5.0 Air Changes
(ACH) at 50 Pascals pressure” has been selected for all the three models. Moreover, infiltration
has been chosen as one of the variables with three different values (Figure 4.26). The different
infiltration values are, first, “HVAC System with no ducts or else with all ducts inside insulated
envelope, 2.0 SLA/ 4.0 ACH50”, second, “HERS verified Air Sealed and Quality Insulation (QII),
1.5 SLA/ 3.0 ACH50”, third, “Passive House Standard ™ extremely tight Air Sealing requirement,
0.3 SLA/ 0.6 ACH50”. The DEFAULT STANDARD DESIGN is set in all scenarios except the
nominated scenarios that are named in one of the infiltration values.
53

(Figure 4.27) Ventilation Cooling.

The ventilation screen has three questions (Figure 4.27). Firstly, the option pertains to the
suitability of “Gentle Air Velocity: air motion up to 160 FPM (48.77 Meter per Minute) (will feel
4.6°F [2.56°C] cooler)” towards sedentary (residential) activities, and its best fit for different types
of indoor air velocity. The other two are “Strong Air Velocity: air motion up to 300 FPM (91.44
Meter per Minute)”, which is very strong airspeed, and “Ignore any Cooling from Air Motion”, in
which there is no air movement from fans and natural ventilation. Secondly, the option “Window
and Doors are manually OPENED if cooling is needed and if Outdoor Temperature is below
Comfort High” is the selected one because “WINDOWS remain SHUT” will not show the
advantages of the thin models or the models that have more façades from the wide models or the
models that have fewer façades. Thirdly, it probes into fan-forced ventilation. It has been chosen
before “No Fans” because all the three models should depend only on air conditioners, heaters,
and natural ventilation to test the models equally. However, it shows an error at the end of the
simulation if the “No Fans” has been chosen. The option, “Whole Fan”, is not suitable for the
project concept because the tested models have separate apartments that cannot share one fan.
Therefore, “Ceiling Fans: Smart Thermostat Occupant Sensors (meaning only one fan running per
occupant)” is the chosen option for the fan-forced ventilation question.
54

(Figure 4.28) Heating and Cooling screen.

At the beginning of the Heating and Cooling screen, it should be chosen one of the two systems,
which are “Reload Any Heat Pump” or “HVAC” (Figure 4.28). The HVAC system has been
chosen because it can give more advanced options and make the heating and cooling systems
separate. The heating and cooling are set up in all the three models at the “Energy Code Minimum
Furnace, 78% Annual Fuel Utilization Efficiency (AFUE)”, and “Energy Code Minimum Air
Conditioner, 13.0 Seasonal Energy Efficiency Ratio (SEER)” because they are the minimum
requirements for the residential buildings.
55

(Figure 4.29) Operable Shading.

The first option is the “Overhangs* (Default Condition) are Fixed All Year, or there are No
Overhangs, also No Interior Shades or Venetian Blinds” in the Operable Shading screen. It is
selected because there are no overhangs and awnings in the three models. However, the operable
shading has been chosen as one of the additional variables with three different values (Figure 4.29).
The different operable shading values are first, “Light Venetian Blinds Are Fixed at 45 Degrees
All Year Long, They Are Never Retracted”, second, “Light Venetian Blinds at 45 Degrees or
Closed Tight Hourly When Indoor Temperature Reaches 3°F (1.67°C) below Comfort High”,
third, “Light Venetian Blinds Closed if Sun is on Window and Indoors is Above Comfort Low, or
3°F (1.67°C) below Comfort High in Winter”.
56

(Figure 4.30) APPLIANCES and PLUG LOUADS: Annual Energy Consumption screen.

There are three base case defaults in the “appliances and plug loads” screen, and they cannot be
modified or erased. These are Cooking, Clothes Drying and Other Electrical (Figure 4.30). The
“Cooking” and “Clothes Drying” consumptions in HEED are default based on the US Single
Family Residence average consumption of “Cooking” which is 29.1 Therms/year, and the average
consumption of “Clothes Drying” which is 37.2 Therms/year. The “Other Electrical” is
13650.483kWh/year, which depends on the total floor area of the model. For that reason, it has
been added nine more cooking and clothes drying consumptions because there are ten apartment
blocks in each different model.
57

(Figure 4.31) SOLAR SYSTEMS: Solar Electric and Solar Water Heating Systems screen.

The project also relies on the choice that there is no renewable energy such as Photovoltaic (PV)
and Solar Domestic Hot Water (SWH) (Figure 4.31). Moreover, there are no other building
technologies like geothermal heating and cooling system, automatic openable windows for natural
ventilation, wind power, and water management. All three models are not storing any energy from
the natural environment for consumption.
58

(Figure 4.32) UTILITY RATES: Residential or Domestic Service Rates screen.

There are many electric and fuel rates for different companies like SCE, SDG&E, PG&E, and
SMUD, and they can be modified in the utility rate screen, which is about how much the price is
for each unit of therm and kWh. For the project, it is not essential because the rates keep
fluctuating, and they do not comprise the primary research objectives (Figure 4.32).
59

(Figure 4.33) ECONOMIC ANALYSIS screen.

The last screen before it presents the results after simulating is the economic analysis screen, which
shows the annual energy cost of each scheme in the first project; the tall thin one. Also, it shows
the savings by comparing one to a scheme to another, and it can compute the years to pay back
annual energy savings. However, this screen is not essential because it is about the costs, a
component that is not one of the goals of the study (Figure 4.33).

In the economic analysis screen, there are only nine schemes in each project at HEED. The first
two schemes, Meets Energy Code and More Energy Efficient in each project come out
automatically by default and cannot be modified or deleted, the last seven schemes of the nine can
be customized. Nonetheless, in each specific model with its location, there are nine different
scenarios. There is also one more without using the cooling and heating systems to show the indoor
temperature and a representation of how it looks like in each different model in the corresponding
city. The plan is to make the third scheme named Default/ Standard/ Minimum requirements,
which is the reference of all different scenarios. The second three schemes are the different
orientation values of ±0° slope, -30° slope, and -45° slope. The last three schemes are different
infiltration values. First, there is an HVAC System with no ducts or else with all ducts inside
insulated envelope, 2.0 SLA/ 4.0 ACH50. Second, here is the HERS verified Air Sealed and
Quality Insulation (QII), 1.5 SLA/ 3.0 ACH50. Finally, there is the Passive House Standard ™
extremely tight Air Sealing requirement, 0.3 SLA/ 0.6 ACH50. The name of this project is Tall
Thin_Los Angeles_S#1-6.

Then, it should be created as a new project named Tall Thin_Los Angeles_S#7-9 which should
encompass the first three schemes: Meets Energy Code, More Energy Efficient and Default/
60

Standard/ Minimum requirements. The second three schemes are the last scenarios of the tall thin
model in Los Angeles which are the different Light Venetian Blinds values. To begin with, fixed
blinds at 45 Degrees All Year Long. Second, Light Venetian Blinds at 45 Degrees or closed tight
hourly when indoor temperature reaches 3°F (1.67°C) below comfort high. Third, Light Venetian
Blinds closed if the sun is on the window and indoor temperature is above comfort low, or 3°F
(1.67°C) below Comfort High in Winter. The seventh scheme is named No H&C, which stands
for No Heating, and Cooling. It implies no heating and cooling for the purpose of examining the
indoor temperate of each model in a different location (Figure 4.35).

Next, medium-medium model in Los Angeles has the same configuration as the tall thin model in
Los Angeles. It is named Medium-Medium_Los Angeles_S#10-15 and Medium-Medium_Los
Angeles_S#16-18 projects. Then, Short Wide_Los Angeles_S#19-24 and Short Wide_Los
Angeles_S#25-27 projects come out. The same organized projects with their schemes of three
models in Los Angles happen to those in New York and Las Vegas (Figure 4.36). Also, there are
three additional projects named MARGED SCHEMES for Tall Thin and Los Angles models
(TTs&LAs), Medium-Medium and New York models (MMs&NYs), and Short Wide and Las
Vegas models (SWs&LVs), which are the collection of No H&C (No Heating and Cooling)
schemes of different projects. These projects have no heating and cooling to compare the indoor
temperate of each model in different locations (Figure 4.37).

(Figure 4.34) First six scenarios in one project at HEED.

61

(Figure 4.35) Las three scenarios with one No Heating and Cooling scheme in another project at
HEED.

(Figure 4.36) All projects in HEED, each project has different schemes
62

(Figure 4.37) No heating and Cooling schemes in one project.

4.1.6 Advanced steps for all models

The advanced steps can manifest themselves after the process is done from the necessary steps,
and these steps can be skipped. Indeed, to have more accurate results, the advanced steps should
proceed. Some of the phases make inquiries about the site and climate, for example, what the
lowest and highest indoor thermal comfort degrees are, which are 70-75°F (21-24°C). In addition,
others inquire about the lighting and daylighting, which have been left as HEED default settings.
Also, there are many inquiries about the internal loads and heat gain to interior space like how
many occupants occupy the building. In regard to this, the observation is 20 people, two people in
one apartment for all models. The Heating, Ventilation and Air Conditioning (HVAC) system can
be modified by changing the infiltration, air changes per hour, thermostat, outdoor temperature,
and duct insulation, manually (Figure 4.38-4.41). Nevertheless, all the available previous selected
necessary steps from HEED have been respected and preserved.
63

(Figure 4.38) Thermal comfort condition, 70-75°F (21-24°C)

(Figure 4.39) Lighting and daylighting screen

64

(Figure 4.40) Internal loads (heat gain to interior space).

(Figure 4.41) Heating, ventilation and air condition systems Design

65

4.1.7 Advanced steps for tall thin model

These are specific advanced steps for the tall thin model such as the Envelope Design Summary
screen, which investigates the floor to floor height; 9.60 feet (2.93m) and the floor to ceiling height;
8.50 feet (2.60m). The reason for picking 9.60 feet is because the building’s height of medium-
medium model equals 48 feet (14.63m), which equals the width and length of the medium-medium
model, thus translating to the medium-medium model taking a medium-medium form (cube). The
other numbers on this screen are just a summary of the tall thin model’s dimensions, areas,
percentages, floors, volumes, roof slope, as well as aged solar and thermal emittance (Figure 4.42).
The Surface Area Design Summary screen shows some information about the windows, walls,
roof areas, transmissivity, and average U factor and wall window ratio, as well as window wall
ratio. Notably, only the wall transmissivity, average U factor, time lag, and decrement factor can
be edited manually (Figure 4.43). The last specific advanced screen is the Thermal Mass screen,
which is about the internal storages like the dimensions and number of the floors, walls, ceilings,
and the interior, which are constant (Figure 4.44).

(Figure 4.42) The envelop design of the tall thin model.

66

(Figure 4.43) The surface area design of the tall thin model.

(Figure 4.44) Thermal mass of the tall thin model (interior storage).

67

4.1.8 Advanced steps for medium-medium model

These are specific advanced steps for the medium-medium model such as the Envelope Design
Summary screen, which investigates the floor to floor height; 9.60 feet (2.93m) and the floor to
ceiling height; 8.50 feet (2.60m). The reason for picking 9.60 feet is because the building’s height
of medium-medium model equals 48 feet (14.63m), which equals the width and length of the
medium-medium model, thus translating to the medium-medium model taking a medium-medium
form (cube). The other numbers on this screen are just a summary of the medium-medium model’s
dimensions, areas, percentages, floors, volumes, roof slope, as well as aged solar and thermal
emittance (Figure 4.45). The Surface Area Design Summary screen shows some information about
the windows, walls, roof areas, transmissivity, and average U factor and wall window ratio, as well
as window wall ratio. Notably, only the wall transmissivity, average U factor, time lag, and
decrement factor can be edited manually (Figure 4.46). The last specific advanced screen is the
Thermal Mass screen, which is about the internal storages like the dimensions and number of the
floors, walls, ceilings, and the interior, which are constant (Figure 4.47).

(Figure 4.45) The envelop design of the medium-medium model.

68

(Figure 4.46) The surface area design of the medium-medium model.

(Figure 4.47) Thermal mass of the medium-medium model (interior storage).

69

4.1.9 Advanced steps for short wide model

These are specific advanced steps for the short wide model such as the Envelope Design Summary
screen, which investigates the floor to floor height; 9.60 feet (2.93m) and the floor to ceiling height;
8.50 feet (2.60m). The reason for picking 9.60 feet is because the building’s height of medium-
medium model equals 48 feet (14.63m), which equals the width and length of the medium-medium
model, thus translating to the medium-medium model taking a medium-medium form (cube). The
other numbers on this screen are just a summary of the short wide model’s dimensions, areas,
percentages, floors, volumes, roof slope, as well as aged solar and thermal emittance (Figure 4.48).
The Surface Area Design Summary screen shows some information about the windows, walls,
roof areas, transmissivity, and average U factor and wall window ratio, as well as window wall
ratio. Notably, only the wall transmissivity, average U factor, time lag, and decrement factor can
be edited manually (Figure 4.49). The last specific advanced screen is the Thermal Mass screen,
which is about the internal storages like the dimensions and number of the floors, walls, ceilings,
and the interior, which are constant (Figure 4.50).

(Figure 4.48) The envelop design of the short wide model.

70

(Figure 4.49) The surface area design of the short wide model.

(Figure 4.50) Thermal mass of the short wide model (interior storage).

71

4.2 Outputs

After having done 81 simulations with added nine simulations of No Heating and Cooling schemes
for indoor temperatures, HEED gives the Energy Use Intensity (EUI), total site energy use, and
hours of passive, heating and cooling results by allowing the user to view the results of each
scheme using a computer mouse. This functionality is not useful because capturing 81 simulated
results proves very difficult to read. However, all the results have been placed in tables that are
more effective. Similarly, other results like the indoor temperature comparisons and energy and
envelop performances have been captured from HEED because it gives clear tables and charts like
bar 3D charts.

4.2.1 Energy Use Intensity (EUI)

EUI is the energy use per square foot at a property, whose unit of measurement is in kBTU/square
feet in a year. One kBTU equals 1,000 BTU, which gives the heat energy amount, and heat is
recognized to be comparable to energy. The table is organized by making the models on the left
side of the table, and each model has the same three cities-- Los Angeles, New York, and Las
Vegas. Moreover, from the upper side of the table, it shows the additional variables, the orientation,
infiltration and Light Venetian blinds. Below these variables, three different values come out for
each of them. The EUI for all the scenarios is between 16 to 50kBTU/sq. ft in a year (Table 4.1).

72

EUI

Variables Orientation Infiltration
Light Venetian
Blinds

Model
Values 0° -30° -45°
2.0
SLA/
4.0
ACH
1.5
SLA/
3.0
ARCH
0.3
SLA/
0.6
ACH
Fixed
Auto.
W/
Sun.
Auto.
W/
Temp.
Unit
Tall Thin
Los
Angeles
30 30 30 30 30 30 26 26 24
kBTU/sq.
ft year
New
York
50 50 50 48 46 41 50 47 49
kBTU/sq.
ft year
Las
Vegas
40 40 40 39 38 37 36 33 33
kBTU/sq.
ft year
Medium-
Medium
Los
Angeles
17 17 17 17 16 16 17 17 17
kBTU/sq.
ft year
New
York
41 41 41 39 37 31 43 41 43
kBTU/sq.
ft year
Las
Vegas
28 28 28 27 26 24 28 26 27
kBTU/sq.
ft year
Short Wide
Los
Angeles
16 16 16 16 16 16 17 16 17
kBTU/sq.
ft year
New
York
40 40 40 39 37 32 42 40 42
kBTU/sq.
ft year
Las
Vegas
25 25 25 24 23 22 25 24 25
kBTU/sq.
ft year
(Table 4.1) Energy Use Intensity (EUI).

73

4.2.2 Total site energy use

By using the same EUI table matrix, it can show the total site energy for each simulated scenario
results. HEED can show these results by only referring to the schemes in each selected project.
The unit of the total site energy used is kWh/year; where kWh is a unit of energy. The total site
energy use for all the scenarios are between 46,371 to 152,081kWh/year (Table 4.2).

Site Energy Use
Variables Orientation Infiltration Light Venetian Blinds
Model
Values 0° -30° -45°
2.0 SLA/
4.0 ACH
1.5 SLA/
3.0
ARCH
0.3 SLA/
0.6 ACH
Fixed
Auto.
W/ Sun.
Auto.
W/
Temp.
Unit
Tall Thin
Los
Angeles
89,443 90,350 90,274 89,950 90,281 91,245 77,854 79,443 72,347
kWh/
year
New
York
150,967 151,295 151,664 145,125 138,671 123,345 152,081 143,577 147,771
kWh/
year
Las
Vegas
120,224 121,072 119,873 117,401 115,598 111,636 107,379 100,787 100,249
kWh/
year
Medium-Medium
Los
Angeles
56,654 57,127 57,101 55,854 55,024 54,208 57,437 56,533 58,194
kWh/
year
New
York
139,577 138,620 138,357 131,499 123,457 104,656 145,001 138,118 144,758
kWh/
year
Las
Vegas
93,957 95,126 95,342 90,760 87,965 81,367 94,868 87,479 90,979
kWh/
year
Short Wide
Los
Angeles
47,605 47,547 47,521 47,090 46,687 46,371 49,568 48,217 50,217
kWh/
year
New
York
118,065 117,481 117,245 112,885 107,560 94,178 121,872 118,201 121,996
kWh/
year
Las
Vegas
72,456 73,069 73,255 70,259 68,278 64,110 74,592 70,451 73,659
kWh/
year
(Table 4.2) Total site energy use.

74

4.2.3 Hours of passive, heating and cooling times

Using the same EUI table matrix can display the numbers of passive, heating, cooling and
uncomfortable hours for all the scenarios. First, there is the table of the passive hours, no heating
and cooling needed, which is between 4943 to 8647 hours in a year that models do not need air
conditioning and heating (Table 4.3). Second, in the table cooling hours, it appears that the range
of turning on the air condition among 5-1163 hours (Table 4.4). Third, the heating hours is in the
range of 3 to 2980 (Table 4.5). Lastly, the uncomfortable hours, which are the hours that model
has been outside the thermal comfort zone while the heating, ventilation or air conditioning try to
make the indoor temperate and humidity get back to the thermal comfort zone (Table 4.6).

No Heating and Cooling Needed

Variables Orientation Infiltration
Light Venetian
Blinds

Model
Values 0° -30° -45°
2.0
SLA/
4.0
ACH
1.5
SLA/
3.0
ARCH
0.3
SLA/
0.6
ACH
Fixed
Auto.
W/
Sun.
Auto.
W/
Temp.
Units
Tall Thin
Los
Angeles
7503 7467 7469 7499 7509 7500 7758 7907 7912
hours
New
York
5497 5497 5487 5597 5695 6008 5416 5717 5537
hours
Las
Vegas
4970 4943 4943 5013 5055 5130 5121 5412 5304
hours
Medium-Medium
Los
Angeles
8072 8027 8004 8056 8040 8008 8254 8349 8362
hours
New
York
5940 5972 5987 6024 6132 6437 5833 6099 5937
hours
Las
Vegas
5458 5414 5402 5510 5544 5593 5484 5853 5726
hours
Short Wide
Los
Angeles
8564 8551 8551 8573 8565 8493 8603 8647 8624
hours
New
York
6200 6226 6234 6256 6226 6643 6102 6239 6122
hours
Las
Vegas
6424 6388 6385 6473 6545 6633 6410 6665 6564
hours
(Table 4.3) Passive hours

75

Cooling Hours

Variables Orientation Infiltration
Light Venetian
Blinds

Model
Values 0° -30° -45°
2.0
SLA/
4.0
ACH
1.5
SLA/
3.0
ARCH
0.3
SLA/
0.6
ACH
Fixed
Auto.
W/
Sun.
Auto.
W/
Temp.
Units
Tall Thin
Los
Angeles
383 402 392 400 414 468 128 36 7
hours
New
York
257 264 262 268 288 325 117 85 68
hours
Las
Vegas
1081 1107 1107 1114 1125 1163 771 589 547
hours
Medium-Medium
Los
Angeles
191 223 241 213 250 352 35 13 4
hours
New
York
149 165 171 161 169 215 95 79 69
hours
Las
Vegas
724 771 782 733 734 780 575 470 456
hours
Short Wide
Los
Angeles
44 53 53 57 81 178 6 7 5
hours
New
York
100 102 104 102 104 103 92 88 83
hours
Las
Vegas
362 366 364 371 375 439 324 302 295
hours
(Table 4.4) Cooling hours

76

Heating Hours

Variables Orientation Infiltration
Light Venetian
Blinds

Model
Values 0° -30° -45°
2.0
SLA/
4.0
ACH
1.5
SLA/
3.0
ARCH
0.3
SLA/
0.6
ACH
Fixed
Auto.
W/
Sun.
Auto.
W/
Temp.
Units
Tall Thin
Los
Angeles
689 697 701 675 653 609 694 670 704
hours
New
York
2704 2697 2709 2592 2474 2124 2975 2740 2980
hours
Las
Vegas
865 869 874 791 734 610 1002 911 1051
hours
Medium-Medium
Los
Angeles
292 295 298 285 266 200 313 307 312
hours
New
York
2431 2372 2350 2336 2224 1876 2651 2435 2651
hours
Las
Vegas
534 516 520 476 433
324 737 487 737
hours
Short Wide
Los
Angeles
74 71 71 52 32 3 112 85 115
hours
New
York
2407 2377 2367 2349 2267 1962 2535 2413 2539
hours
Las
Vegas
358 375 380 292 237 114 492 364 494
hours
(Table 4.5) Heating hours

77

Uncomfortable Hours

Variables Orientation Infiltration
Light Venetian
Blinds

Model
Values 0° -30° -45°
2.0
SLA/
4.0
ACH
1.5
SLA/
3.0
ARCH
0.3
SLA/
0.6
ACH
Fixed
Auto.
W/
Sun.
Auto.
W/
Temp.
Units
Tall Thin
Los
Angeles
185 194 198 186 184 183 180 147 137
Hour
s
New
York
302 302 302 303 303 303 252 218 175
hours
Las
Vegas
1844 1841 1836 1842 1846 1857 1866 1848 1858
hours
Medium-Medium
Los
Angeles
205 215 217 206 204 200 158 91 82
hours
New
York
240 251 252 239 235 232 181 147 103
hours
Las
Vegas
2044 2059 2056 2041 2049 2063 1964 1850 1841
hours
Short Wide
Los
Angeles
78 85 85 78 82 86 39 21 16
hours
New
York
53 55 55 53 53 52 31 20 16
hours
Las
Vegas
1616 1631 1631 1624 1603 1574 1534 1429 1407
hours
(Table 4.6) Uncomfortable hours

78

4.2.4 Indoor temperature

This kind of information is significant because it shows how the different building masses are
reacting with the outdoor temperature of each climate of the picked city by showing the indoor
temperature. Even if they have almost the same massing volume, total floor area, WWR, plan
aspect ratio, materials, and many other things mentioned earlier with the outdoor temperature of
each climate of the picked city, several models gain and lose heat in trends that differ from the
others. Notably, some models are gaining heat from outdoors when they need it and losing heat
when they need cooling, and some are reacting oppositely. All indoor temperature charts cannot
be shown on one page because they are nine simulations without heating and cooling, and HEED
cannot make the legends of temperature degree ordinarily in the comparison screen. HEED can
only illustrate these indoor temperature comparisons between two schemes. First, indoor
temperature comparisons are between all tall thin models in its cities, which means between Los
Angeles and New York, then Los Angeles and Las Vegas, then New York and Las Vegas (Figure
4.51 - 4.53).

(Figure 4.51) Indoor temperature between tall thin model in Los Angeles and tall thin model in
New York.

79

(Figure 4.52) Indoor temperature between tall thin model in Los Angeles and tall thin model in
Las Vegas.

(Figure 4.53) Indoor temperature between tall thin model in New York and tall thin model in Las
Vegas.
80

Second, indoor temperature comparisons are between all medium- medium models in its cities,
which means between Los Angeles and New York then Los Angeles and Las Vegas, then New
York and Las Vegas (Figure 4.54 - 4.56).

(Figure 4.54) Indoor temperature between medium- medium model in Los Angeles and medium-
medium in New York.
81

(Figure 4.55) Indoor temperature between medium- medium model in Los Angeles and medium-
medium in Las Vegas.

(Figure 4.56) Indoor temperature between medium- medium model in New York and medium-
medium in Las Vegas.
82

Third, indoor temperature comparisons are between all short wide m models in its cities, which
means between Los Angeles and New York, then Los Angeles and Las Vegas then New York and
Las Vegas (Figure 4.57 - 4.59).

(Figure 4.57) Indoor temperature between short wide model in Los Angeles and short wide in New
York.
83

(Figure 4.58) Indoor temperature between short wide model in Los Angeles and short wide in Las
Vegas.

(Figure 4.59) Indoor temperature between short wide model in New York and short wide in Las
Vegas.
84

Forth, indoor temperature comparisons are between all models in Los Angeles, which means
between the tall thin and medium- medium models then tall thin and short wide models, then
medium- medium and short wide models (Figure 4.60 - 4.62).

(Figure 4.60) Indoor temperature between tall thin model in Los Angeles and medium- medium
model in Los Angeles.

85

(Figure 4.61) Indoor temperature between tall thin model in Los Angeles and sort wide model in
Los Angeles.

(Figure 4.62) Indoor temperature between medium- medium model in Los Angeles and short wide
model in Los Angeles.
86

Fifth, indoor temperature comparisons are between all models in New York, which means
comparison between the tall thin and medium- medium models, then tall thin and short wide
models, and finally medium- medium and short wide models (Figure 4.63 – 4.65).

(Figure 4.63) Indoor temperature between tall thin model in New York and medium- medium in
New York.

87

(Figure 4.64) Indoor temperature between tall thin model in New York and short wide in New
York.

(Figure 4.65) Indoor temperature between medium- medium model in New York and short wide
in New York.
88

Sixth, there should be indoor temperature comparisons between all models in Las Vegas, which
means between the tall thin and medium- medium models, then between tall thin and short wide
models, and finally between medium- medium and short wide models (Figure 4.66 - 4.68).

(Figure 4.66) Indoor temperature between tall thin model in Las Vegas and medium- medium in
Las Vegas.
89

(Figure 4.67) Indoor temperature between tall thin model in Las Vegas and short wide in Las
Vegas.

(Figure 4.68) Indoor temperature between medium- medium model in Las Vegas and short wide
in Las Vegas.
90

4.2.5 Envelope performance

The envelope performance shows detailed information like the total floor area, roof, skylight U
factor, wall, and window U factor, percentage window area by floor area, percent south glazing by
floor, percent non-south glazing by floor, and cost of net energy. However, it has been showing
this to offer insight into the most important two things in the envelope performance, which are
heat loss, BTUh, and envelop conduction, BTUh/°F. The first two charts and tables in this
subheading show the results of the first nine scenarios, the results of the tall thin model in Los
Angles scenarios, except the first three schemes in the first tables and charts, and the last scheme
in the second table and a chart (Figure 4.69 and 4.70).

(Figure 4.69) The envelop performance of the last six schemes, different orientation and infiltration
values, of the tall thin model in Los Angeles. (in schemes numbers four to nine there is an
abbreviation, S#, means Scenario Number).
91

(Figure 4.70) The envelop performance of the schemes number four to six, different blinds values,
of the tall thin model in Los Angeles. (in schemes numbers four to six there is an abbreviation, S#,
means Scenario Number).

Because the envelope conduction not affected by any of the different orientation, infiltration and
blind values within the same model and location, it has been chosen as the main entity to facilitate
the comparison of the envelope in different modeling forms and locations. The results of the
envelop conduction come out differently if only the model or location are changed (Figure 4.71 –
4.73).

92

(Figure 4.71) The envelop performance of all tall thin models in different locations and all Los
Angeles models in different models. (No H&C means No Heating and Cooling, TT is Tall thin
model, MM is Medium-Medium model, and SW is Short Wide model)

93

(Figure 4.72) The envelop performance of all medium-medium models in different locations and
all New York models in different models. (No H&C means No Heating and Cooling, TT is Tall
thin model, MM is Medium-Medium model, and SW is Short Wide model)

94

(Figure 4.73) The envelop performance of all short wide models in different location and all Las
Vegas models in different models. (No H&C means No Heating and Cooling, TT is Tall thin
model, MM is Medium-Medium model, and SW is Short Wide model)

95

4.2.6 Energy performance

In (Table 4.1) Energy Use Intensity (EUI), some numbers are marked in yellow. First, the last three
scenarios, which are the different blinds values in the tall thin model in Los Angeles. Second, the
middle three scenarios, which denote the different infiltration values in the tall thin model in New
York. Third, the different blinds values in the last three scenarios of the tall thin model in Las
Vegas. Forth, the middle scenarios that are the different infiltration values in the medium-medium
model in New York. Fifth, and the last three scenarios are the different blinds values in the short
wide model in New York. These scenarios show how been signifying reduced the EUI by just one
of the additional variables. Therefore, it has been chosen to illustrate how these scenarios decrease
among the other scenarios in the same modeling form and location (Figure 4.74 - 4.78).

(Figure 4.74) The energy performance of the schemes number four to six, the different blinds
96

values, in the tall thin model in Los Angeles (in schemes numbers from four to six there is an
abbreviation which is S#, means Scenario Number)

(Figure 4.75) The energy performance of the last three schemes, the different infiltration values,
in the tall thin model in New York (in schemes numbers from four to six there is an abbreviation,
S#, means Scenario Number)

97

(Figure 4.76) The energy performance of the schemes number four to six, the different blinds
values, in the tall thin model in Las Vegas (in schemes numbers from four to six there is an
abbreviation, S#, means Scenario Number)

98

(Figure 4.77) The energy performance of the last three schemes, the different infiltration values,
in the medium-medium model in New York (in schemes numbers four to nine there is an
abbreviation, S#, means Scenario Number)

99

(Figure 4.78) The energy performance of the schemes number four to six, the different blinds
values, in the short wide model in New York (in schemes numbers four to six there is an
abbreviation, S#, means Scenario Number)

100

4.3 Summary

Each model described how it had been designed to step by step and shone a light on why it had
been selecting every building’s detail by simultaneously and separately, providing insight into
precise attributes such as the building form and window size. It is also observable that HEED can
only save nine schemes/scenarios in every one project, so it has presented 21 projects for the tested
81 simulations. Here, each project has seven to nine schemes/scenarios. Moreover, some schemes
in the projects are copies from others due to the need of comparing some components of the
schemes such as the No heating and cooling schemes. The first two schemes in every created
project are always generated automatically by HEED with unmodified default settings, so it has
been separating every model and its location in two different projects (Figure 4.34 – 4.37).
The results have provided details of each simulated scheme/scenario by revealing the Energy Use
Intensity (EUI), total site energy use, passive, heating and cooling hours, indoor temperature
comparisons as well as energy and envelop performance results by showing the tables and chart,
which include bar charts and 3D charts. After getting all the needed information and closing the
software tool, HEED, it shows a summary table as the last screen before closing. Because the Short
Wide_LA_S#55-60 project was the last project that the tool has been working on, it can be the
summary table is observable. It shows mostly how much electricity and fuel quantities are
consumed, as well as total costs. Also, it shows the net energy kWh (site), which is illustrated in
(Table 4.2).
101

(Figure 4.79) The summary table of Short Wide_LA_S#55-60 project. (in schemes numbers four
to nine there is an abbreviation, S#, means Scenario Number)

102

5. DISCUSSION

The results show a wide range of information about the differences between the energy
performance of the three residential different medium building scale forms, tall thin, medium-
medium and short wide, but the massing volume, the total floor area, Window Wall Ratio (WWR),
and plan aspect ratio are equivalent. Also, all building elements have been combined such as the
facade material, window glass, roof, construction material and system, building function, heating,
air conditioning, insulation, ventilation, curtain type according to the building code of all the three
cities. Also, the amount of electricity and gas consumption for cooking, laundry, and other routine
uses are united, and no type of renewable energy, such as solar cells, was not used to obtain
electricity or heat water. The rate of financial cost for electrical and gas uses was disregard because
the rate may change from time to time and place to place for several reasons beyond the
performance of the buildings or their natural environment. The thermal comfort zone is determined
between 70 and 75°F (21-24°C). The rest of the settings, for instance, lighting, daylighting and
how to calculate the internal heat were not changed from HEED sittings.

All building energy options are taken from the US Building Energy Code. Building options have
been standardized from each city's building code. This has been achieved by taking the highest
building requirements from each city; for example, the window glass type (Table 4.0). Three fixed
locations, Los Angeles, New York, and Las Vegas are added for each of the three selected models.
Then, the value of an additional variable was added from three additional variables, orientation,
infiltration, and Light Venetian Blinds, to test its effect on each building form in one of the three
locations. For each additional variable, there are three different values. The values of the
orientation variable are ±0°, -30°, and -45° slopes. The values of the infiltration variable are Sealed
HVAC Ducts + Building Air Barrier, 2.0 SLA/ 4.0 ACH, Verified Air Sealed + Quality Insulation
Installation, 1.5 SLA/ 3.0 ACH, and Passive House Standard, 0.3 SLA/ 0.6 ACH. The values of
the Light Venetian Blinds variable are fixed mode, at 45°, closed mode, when the sun is on the
window and indoors is above comfort low, or 3°F below comfort high in winter, and last mode is
automated with temperature, at 45° or closed tight hourly when the indoor temperature reaches
3°F below comfort high.

5.1 Evaluation of Workflow

Some difficulties and other issues have emerged in the process of the project work which is that
HEED could not give a manually designing flexibility of choosing the dimensions of the length
and width of models, which led to a slight change to the volume and area of each model, making
them completely unequal. Also, one of the problems that cannot be resolved is that windows have
the same dimensions and spaces in between. The number of windows also cannot be equal because
the area of the facades is different between all models even if they have equal site area and volume.
The problem of indoor moisturizing and drying systems are not existed as a building option to
design a model in HEED, which may be the reason why there are some uncomfortable hours even
with heating, conditioning and ventilation systems are exist in HEED. This has resulted to a lot of
uncomfortable hours in Las Vegas.

103

5.1.1 Minor differentiations in modeling volumes and total floor areas

There is a slight difference between the total floor area in the three models. Since HEED does not
allow to create free length and width dimensions for each tested model, but it allows to write or
put numbers manually on the floor to floor height of the three models. The length and width
dimensions in HEED are limited to filling square spaces, each square with dimensions 4x4 feet
(1.22x1.22m) or 16 square feet (1.49m2). Accordingly, the construction area is chosen for each of
the following models. It should also be noted that HEED only provides a grid network of 30x30
squares of building area equals 14,400 square feet (1,338 m2) which also makes it impossible to
make models with larger spaces than that in HEED. Models should, therefore, have a medium or
smaller building area. The used total floor area is 1,000m2 (10,764 square feet), which became the
standard total floor area for each model to approach as much as possible of this space —
considering that each model must have the same plan aspect ratio, a square shape. Also, it slightly
affects the massing volume of each model because the floor to floor height is 9.6 feet (2.93m).
This height is selected because the length and width dimensions of the medium-medium model are
48 feet (14.63m) with five stories. Therefore, the height of the medium-medium model should be
equal the length and width dimensions of the medium-medium model, the floor to floor height of
the medium-medium model should be 9.6 feet (2.93m), and the rest of the models should have the
same floor to floor height to make the comparison fair between all models.

Therefore, the total floor area of the tall thin model should be 1,000m2 (10,764 square feet) with
ten stories which means 100m2 (1,076 square feet) in each story. 100m2 ÷ 1.49m2 (4x4 feet) =
67.11 squares of 4x4 feet. 67 squares of 4x4 feet equal 99.83m2 (1,075 square feet). However, to
make sure the tall thin model has a square plan, it must have 64 squares, so the length and width
are 8x8 squares, means 95.36m2 (1,032 square feet). Which is the closest area can be done in
HEED to what has been chosen. The tall thin model has ten floors, means the total floor area is
95.36m2 x 10 floors = 953.6m2 (1,032 square feet). Moreover, the floor to floor height is 9.6 feet
(2.93m), so the mass volume of the tall thin model is 2860.8m3 (101,028.2 cubic feet) (Figure
4.42).

The total floor area of the medium-medium model should be 1,000m2 (10,764 square feet) with
five stories which means 200m2 (2152.8 square feet) in each story. 200m2 ÷ 1.49m2 (4x4 feet) =
134.23 squares of 4x4 feet. 134 squares of the 4x4 feet equal 199.66m2 (2,149.1 square feet).
However, to make sure this model has a square plan, it must have 144 squares, so the length and
width are 12x12 squares, means 214.05m2 (2,304 square feet). Which is the closest area can be
done in HEED to what has been chosen. The medium-medium model has five floors, means the
total floor area is 1070.25m2 (11,520 square feet). Moreover, the floor to floor height is 9.6 feet
(2.93m), so the mass volume of the medium-medium model is 3210.75m3 (113,386.6 cubic feet)
(Figure 4.45).

The total floor area of the short wide model should be 1,000m2 (10,764 square feet) with one story.
1000m2 ÷ 1.49m2 (4x4 feet) = 671.14 squares of 4x4 feet. 671 squares of 4x4 feet equal 999.79
m2 (10761.7 square feet). However, to make sure this model has a square plan, it must have 625
squares, so the length and width are 25x25 squares, means 929m2 (10,000 square feet). Which is
the closest area can be done in HEED to what has been chosen. Moreover, the floor to floor height
104

is 9.6 feet (2.93m), so the mass volume of the short wide model is 3021.72m3 (106,711 cubic feet)
(Figure 4.48).

5.1.2 Sizes and spaces between windows

The WWR is 25% for all models. Moreover, the windows in the three models are distributed in
parallel and balance from right to left of each facade's story, and they are symmetrical and
centralized in the middle height of each story. The only thing that could not be done was to make
the windows in all three models have the same surface area since it could not be done because the
tall thin model had a larger facade area than the medium-medium model. Also, the facade area in
the short wide model is the least between the other models due to geometric reasons. Therefore,
the roof area of the tall thin is less than the medium-medium model, and the roof area of the short
model is the largest between the tested models. Therefore, the windows cannot get the same space
either in total or individually, and this also causes the different dimension between each window
for the other for each model. However, the surface area of each window is approximated in all
models. The required surface area for each window of the models is 16 square feet, 4x4 feet (Figure
4.11, 4.15, and 4.18).

5.1.3 Reasons of uncomfortable hours

One of the things that came up in the end and was not solved was the uncomfortable hours, which
are the calculated hours when the indoor temperature is outside the thermal comfort zone
throughout the year. It is logical to have some uncomfortable hours during the year such as that
the indoor temperature is experiencing a sharp drop and rise of the outdoor temperature, and it
needs heating and air conditioning systems to approximately an hour to shift the indoor
temperature inside the thermal comfort zone. The thermal comfort zone was previously placed
between 70-75°F in HEED for all models at the selected sites. However, all models when they are
placed in different cities, they were seen to have some acceptable uncomfortable hours, between
16 to 300 hours, except in Las Vegas, which was seen to have a lot of uncomfortable hours, from
1407 to 2063 hours throughout the year (Table 4.6).

There are several possible causes for this phenomenon. The first is that Las Vegas has a desert
climate, which means that the temperature varies dramatically between summer and winter, as well
as day and night. Summer temperatures exceed 110°F, and Winter temperatures are below 30°F
(Figure 3.5). It is freezing at night and very hot during the day time, where the average difference
between them is more than 20 degrees Fahrenheit per day, means that the indoor temperature will
also be affected, and heating and air conditioning systems will try to make the indoor temperature
inside the thermal comfort zone between 70-75°F. The Las Vegas weather makes the indoor
temperature uncomfortable at various times at the three models in Las Vegas. However, indoor
temperatures at the three models in Los Angeles and New York are somewhat acceptable, 16 to
300 hours throughout the year.

The first probable cause of numerous uncomfortable hours in Las Vegas is because it is in a desert
climate, and its temperature is tremendous differ because of the dry weather in Las Vegas.
105

Therefore, it found another possibility which is that HEED does not include building options for
moisturizing and drying systems the designing model process. The thermal comfort zone is known
that is between 70-75°F, and the thermal comfort zone also has a humidity limit, about 20 to 80%.
It may be calculated every hour when the indoor humidity is outside the thermal comfort zone
because most of the humidity in Las Vegas is less than 20%, and HEED does not provide
moisturizing systems to solve the problem of the indoor drought model (Figure 3.5). Therefore,
the indoor drought may make the number of uncomfortable hours very high in Las Vegas when
indoor humidification systems are not used.

5.2 Comparison of Different Models Results

In this comparison, the differences, similarities, and causes of the varied results of the models are
discussed in general and detail. At first, the EUI results are discussed in general about the climate
impact of the building performance, and how the results of the Los Angeles models have become
highly efficient. Hence, the results of the EUI in general about the building form impact the
building energy and envelope performances and how the results of each model became different.
Then, the EUI outcomes are carefully studied in comparison to the most spectacular scenarios.
Second, there will be a comparison of the passive, cooling, heating hours. Multiple charts have
been presented to explain how the hours of passive air conditioning and heating come out for each
model that has increased or decreased by showing each scenario. Third, comparing the 3D chart
of the indoor temperature after turning off the air conditioning and heating systems for all models
in each city to test the models' indoor temperature. Finally, comparing the envelope and energy
building performance to find out why some EUI results differ for each scenario.

5.2.1 Comparing the EUI results between the three models

Firstly, the results of the EUI models can be compared in general, that the results of all Los Angeles
models are low, from 16 to 30kBTU/sq. ft year in all scenarios because the outside temperature in
Los Angeles nears the thermal comfort zone temperatures (Table 4.1). The Los Angeles weather
makes the indoor heating, and air conditioning systems work less and make the results of the EUI
incredibly low compared to the New York and Las Vegas indoor models, which need to be warmed
or cooled by using the heating, ventilation, and air conditioning systems due to the uncomfortable
climate factor there. The EUI New York results are generally higher, between 31 to 50kBTU/sq.
ft year, because the models need to warm up the indoor almost all year and continuously due to
the cold weather in New York. The EUI results of three models in Las Vegas are less than New
York, ranging from 22 to 40kBTU/sq. ft year.

Secondly, the difference results between a specific model in different cities. For example, the
results of the EUI of the tall thin model in all selected cities are between 24 to 50kBTU/sq. ft year.
The difference between the results of the EUI in the medium-medium model is between 16 to
43kBTU/sq. ft year. It can be detected that the medium-medium model is way better than the
energy efficiency of the tall thin model. The difference between the EUI results of the short wide
model is from 16 to 40kBTU/sq. ft year. Therefore, the short wide model is slightly better than the
medium-medium model and the most energy efficient building form among all, generally.
106

The results of all EUI also show that some scenarios that give different results for each model in
each site because each scenario contains a different value of additional variables that often add
higher energy efficiencies or reduce the energy efficiency of the model form in each location.
Table 4.1 shows that some numbers contain a yellow background. These numbers yield
tremendous results after adding only one value of each additional variable to each model in a site.
All results of the different values of the third additional variable, the Light Venetian Blinds, for
the tall thin model in Los Angeles have become more energy efficient, their results better by 4 to
6kBTU/sq. ft year than the baseline scenario which is the 0° slope at the orientation variable, which
is precisely the same but without any Light Venetian Blinds.

All models in New York energy efficiency results have astoundingly risen by an average of 2 to
9kBTU/sq. ft year when the different values of the second additional variable, infiltration system,
have been used. The different values of the second additional variable, infiltration system, did not
effectively change the EUI results of Los Angeles and Las Vegas models. Changing the building
orientation in all scenarios generates the same EUI results for all scenarios. There is a noticeable
improvement when using different values of the third variable, Light Venetian Blinds, for the tall
thin model in Las Vegas if compared to its first scenario, between 4 and 7kBTU/sq. ft year.

The EUI results in the medium-medium and short wide models’ scenarios in New York are less
energy efficient when using all different values of the third variable, Light Venetian Blinds,
between 1 to 2kBTU/sq. ft year, if compared to the corresponding baseline scenario, Slope 0°
scenario. Hence, it indicates that using blinds in New York in the medium-medium and short wide
models make the building consume more energy for heating, where blinds prevent solar radiation
from heating the indoor. However, the results of the tall thin model scenarios in New York gave
better energy efficiency results when using the different values of the third variable, Light Venetian
Blinds, compared to the first scenario that is similar but does not contain blinds.

5.2.2 Hours of passive, heating and cooling times

At first, the hours when the heating and cooling are not needed called passive hours, and generally,
the following models outperform them: the short wide model and medium-medium model, then
the tall thin model. The more hours that the models do not need to be heated or cooled the less
energy use and become more energy efficient (Table 4.3). The following charts show how the
passive hours' difference is analyzed for each form in all scenarios (Figure 5.0 to 5.5).

107

(Figure 5.0) The passive hours in all Los Angeles models. (1 is 0° Slope scenario, 2 is 30° Slope
scenario, 3 is 45° Slope scenario, 4 is 2.0 SLA/ 4.0 ACH scenario, 5 is 1.5 SLA/ 3.0 ARCH
scenario, 6 is 0.3 SLA/ 0.6 ACH scenario, 7 is Fixed Blinds scenario, 8 is Auto. W/ Sun. scenario,
9 is Auto. W/ Temp. scenario).

6800
7000
7200
7400
7600
7800
8000
8200
8400
8600
8800
1 2 3 4 5 6 7 8 9
Hours
Hours of passive times in all Los Angeles models
Tall Thin@LA Medium-Medium@LA Short Wide@LA
108

(Figure 5.1) The passive hours in all New York models. (1 is 0° Slope scenario, 2 is 30° Slope
scenario, 3 is 45° Slope scenario, 4 is 2.0 SLA/ 4.0 ACH scenario, 5 is 1.5 SLA/ 3.0 ARCH
scenario, 6 is 0.3 SLA/ 0.6 ACH scenario, 7 is Fixed Blinds scenario, 8 is Auto. W/ Sun. scenario,
9 is Auto. W/ Temp. scenario).

0
1000
2000
3000
4000
5000
6000
7000
1 2 3 4 5 6 7 8 9
Hours
Hours of passive times in all New York models
Tall Thin@NY Medium-Medium@NY Short Wide@NY
109

(Figure 5.2) The passive hours in all Las Vegas models. (1 is 0° Slope scenario, 2 is 30° Slope
scenario, 3 is 45° Slope scenario, 4 is 2.0 SLA/ 4.0 ACH scenario, 5 is 1.5 SLA/ 3.0 ARCH
scenario, 6 is 0.3 SLA/ 0.6 ACH scenario, 7 is Fixed Blinds scenario, 8 is Auto. W/ Sun. scenario,
9 is Auto. W/ Temp. scenario).

0
1000
2000
3000
4000
5000
6000
7000
1 2 3 4 5 6 7 8 9
Hours
Hours of passive times in all Las Vegas models
Tall Thin@LV Medium-Medium@LV Short Wide@LA
110

(Figure 5.3) The passive hours in all tall thin models.

(Figure 5.4) The passive hours in all medium- medium models.
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
0° 30° 45° 2.0 SLA/ 4.0
ACH
1.5 SLA/ 3.0
ARCH
0.3 SLA/ 0.6
ACH
Fixed Auto. W/
Sun.
Auto. W/
Temp.
Hours
Hours of passive times in all tall thin models
Tall Thin Los Angeles Tall Thin New York Tall Thin Las Vegas
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
0° 30° 45° 2.0 SLA/ 4.0
ACH
1.5 SLA/ 3.0
ARCH
0.3 SLA/ 0.6
ACH
Fixed Auto. W/
Sun.
Auto. W/
Temp.
Hours
Hours of passive times in all medium-medium models
Medium-Medium Los Angeles Medium-Medium New York Medium-Medium Las Vegas
111

(Figure 5.5) The passive hours in all short wide models.

The cooling hours are detailed in Table 4.4 where the average cooling hours in the short wide
models are the lowest numbers of hours and the best, followed by the medium-medium model,
then the tall thin model. It is also evident that the average cooling hours are significantly reduced
when the third additional variable is put in place, Light Venetian Blinds, of all its values, compared
to the additional variables, orientation and infiltration, of all their values.
The heating hours appear less in the short wide models, then the medium-medium model and in
the latter the tall thin model (Table 4.5). It appears that whenever the second variable is used,
infiltration, with all its different values in all scenarios, the number of heating hours decrease.
Moreover, whenever a lower Specific Leakage Area/ Air Change per Hour (SLA/ ACH) is selected
from the infiltration system, the number of heating hours reduce.

5.2.3 Indoor temperature

First, the 3D charts of the indoor temperature between the tall thin and medium- medium models
in Los Angeles show that tall thin model is cooler than the medium- medium model, then the short
wide model comes after (Figure 4.60 and 4.61). Also, the indoor temperature of the short wide
model is the nearest Los Angeles model to the thermal comfort zone, which makes it the best
model for saving energy (Figure 4.62).

Second, the indoor temperature charts between all models in New York confirm that the tall thin
model is a little cooler than the medium- medium model, and the short wide model is warmer than
the medium- medium model in New York (Figure 4.63, 4.64 and 4.65). Also, it is tough to know
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0° 30° 45° 2.0 SLA/ 4.0
ACH
1.5 SLA/ 3.0
ARCH
0.3 SLA/ 0.6
ACH
Fixed Auto. W/
Sun.
Auto. W/
Temp.
Hours
Hours of passive times in all short wide models
Short Wide Los Angeles Short Wide New York Short Wide Las Vegas
112

which model is nearer to the thermal comfort zone because the average Fahrenheit degree in the
legends is not accurate enough to estimate.

Third, the 3D indoor temperature charts between the tall thin and medium- medium models in Las
Vegas illustrate that the tall thin model is cooler than the medium- medium model, then the short
wide model comes after (Figure 4.66 and 4.67). Moreover, the indoor temperature of the short
wide model is the nearest Las Vegas model to the thermal comfort zone, which crafts it the most
significant model for conserving energy, and not in use as the other models (Figure 4.68).

5.2.4 Envelope and energy performances

The most valuable two information in the envelope performance is heat loss, BTUh, and envelope
conduction, BTUh/°F. In Figure 4.69 and 4.70, they can show the heat loss models in this project
work change when the infiltration, location, and building formation changed. When it added some
controlled and fixed blinds or changed the building orientation, the heat loss is constant. However,
the envelope conduction results are constant even if any of the different value of the additional
variables has been altered. The only two factors which change over the envelope conduction
outcomes are the location and building formation (Figure 4.71 and 4.73).

In Figure 4.74, the energy performance results of the scheme’s numbers four to six, the different
values of the third additional variable, Light Venetian Blinds, in the tall thin model at Los Angeles.
They show the total net fuel consumed between 170,545-197,180kBTU, compared to the baseline,
scheme number three, Default/Slandered/Minimum scheme, consumption which is 221,545kBTU,
so, the Light Venetian Blinds values give the opportunity to save fuel as much as about 25,000-
50,000kBTU in this model. Also, its total electricity range is among 21,652-22,931kWh and,
compared to its baseline result, 24,512kWh. The Light Venetian Blinds scenarios/values in the tall
thin model in Los Angeles are also saving about 1,500-3,000kWh, electricity than its baseline
scenario.

In Figure 4.75, the energy performance results of the scheme’s numbers seven to nine, the different
values of the second additional variable, infiltration, in the tall thin model at New York. They show
the total net fuel consumed between 331,777-404,771kBTU, compared to the baseline, scheme
number three, Default/Slandered/Minimum scheme, consumption which is 424,258kBTU.
Therefore, the infiltration values give the opportunity to save fuel as much of 20,000-90,000kBTU,
in this model. Also, its total electricity range is among 26,106-26,493kWh and compared to its
baseline result, 26,623kWh. The infiltration scenarios/values in the tall thin model in Los Angeles
are also saving about 150-500kWh electricity than its baseline scenario.

In Figure 4.76, the energy performance results of the scheme’s numbers seven to nine, four to six,
the different values of the third additional variable, Light Venetian Blinds, in the tall thin model at
Las Vegas. They show the total net fuel consumed between 209,186-215,242kBTU compared to
the baseline, scheme number three, the Default/Slandered/Minimum scheme, consumption which
is 241,213kBTU. Therefore, the infiltration values give the opportunity to save fuel as much as
about 26,000-32,000kBTU, in this model. Also, its total electricity range is among 38,939-
44,295kWh and compared to its baseline result, 49,528kWh. The Light Venetian Blinds
113

scenarios/values in the tall thin model at Las Vegas are also saving about 5,000-10,000kWh
electricity than its baseline scenario.

In Figure 4.77, the energy performance results of the scheme’s numbers seven to nine, the different
values of the second additional variable, infiltration, in the medium-medium model in New York.
They show the total net fuel consumed between 264,990-354,597kBTU compared to the baseline,
scheme number three, the Default/Slandered/Minimum scheme, consumption which is
381,316kBTU. Therefore, the infiltration values give the opportunity to save fuel as much as about
27,000-116,000kBTU in this model. Also, its total electricity range is among 26,992-27,572kWh
and, compared to its baseline result, 27,819kWh. The infiltration scenarios/values in the medium-
medium model in New York are also saving about 250-825kWh electricity than its baseline
scenario.

In Figure 4.78, the energy performance results of the scheme’s numbers four to six, the different
values of the third additional variable, Light Venetian Blinds, in the short wide model in New
York. They show the total net fuel consumed between 317,728-326,731kBTU compared to the
baseline, scheme number three, the Default/Slandered/Minimum scheme, consumption which is
317,391kBTU. Therefore, the Light Venetian Blinds values give the opportunity to consume more
fuel as much as about 300-9,000kBTU in this model. Also, its total electricity range is among
25,076-26,171kWh and, compared to its baseline result, 25,043kWh, it can be found that the Light
Venetian Blinds scenarios/values in the short wide model in New York are surprisingly losing
about 30-1,000kWh electricity than its baseline scenario.

5.3 Summary

To sum up, first, a review of the entire project is given out before the discussion started, such as
what are the constants and variables of the project and why they were selected and explain the
work plan in a simplified manner which is the workflow was in line with the methodology. The
sites selected and additional variables aid in testing some of the previous studies such as weather,
orientation, infiltration and some building controls, then simulate each scenario of the 81 scenarios
which were designed to confirm the validation of the results between the three models with their
locations. Then with their three different values of the three additional variables come later to
explore the energy efficiency of the common necessary building forms. Second, the workflow of
the project is articulated by mentioning some of the obstacles which occurred such as the limitation
of HEED abilities and the impossibility of making windows equal in quantity, dimensions, and
spaces between each other for geometrical reasons, which may be a factor which alters the project
results. It has been approximating the total floor area of all models and bordering the surface area
of one window to reduce the differences between the equivalent models. Lastly, the results of the
three models are discussed by comparing the EUI, the passive, cooling, and heating hours, and the
energy and envelope performance of each scenario. Besides, the indoor temperatures of all the
models in their different sites are compared by turning off the air conditioning and heating systems
to test these models without the interference of energy to know the actual indoor temperature of
each model.

114

6. CONCLUSION, SCOPE, AND FUTURE WORK

The final review is done in the conclusions by comparing the EUI results of the three models by
comparing the baseline scenario, the first scenario; of the work in the three cities to test the validity
of the hypotheses. The framework is also reviewed by mentioning all three different values of the
three additional variables, and what are the parameters of the work to make the results credible to
test the validity of the hypotheses.

A complete evaluation of the methodology is described and how it is consistent with the workflow
at all levels with recent additional scenarios to find the indoor temperatures of each model without
cooling and heating systems for all cities. Also, it has shown what improvements have been made
after noticing some obstacles with the workflow, such as the building and window areas that have
been modified as much as possible due to geometrical and HEED restrictions. Finally, the potential
future works show how it can be done for this project, including future solutions to some of the
difficulties that happened in the project.

6.1 Conclusion and Scope of Work

The conclusions and the validity of the first hypothesis have been mentioned after reviewing the
final and conclusive results of the work. It has been determined what the most building form gives
higher energy efficiency is. Also, the validity of the second hypothesis has been reviewed through
the same results as the first hypothesis. The work scope of the project will also be reviewed, which
are the determinants, constants, and variables and their different values.

6.1.1 Conclusion of work

In the first hypothesis, it says that the short wide buildings are giving more chances to conserve
energy rather than the tall thin buildings; usually when they are based on the data that has been
set. Also, the medium-medium (cube) buildings will give EUI results between the tall thin and
short wide buildings. A review of EUI results can be presented to see how the hypothesis is
supported if the baseline scenario, Scenario number 1, for each model is compared between the
other models in the same location (Table 4.1).
• The main scenario of the Los Angeles models is as follows:
o Tall thin, 30kBTU/sq. ft year.
o Medium-medium, 17kBTU/sq. ft year.
o Short wide, 16kBTU/sq. ft year.
• The main scenario of the New York models is the following:
o Tall thin, 50kBTU/sq. ft year.
o Medium-medium, 41kBTU/sq. ft year.
o Short wide, 40kBTU/sq. ft year.
• The main scenario of the Las Vegas models is the following:
o Tall thin, 40kBTU/sq. ft year.
o Medium-medium, 28kBTU/sq. ft year.
o Short wide, 25kBTU/sq. ft year.
115

The average EUI result of the tall thin models in all selected cities is 40kBTU/sq. ft year, and the
average EUI result of the medium-medium models in the three cities is 28.67kBTU/sq. ft year.
Finally, the average result of the EUI for the short wide models in all its cities is 27kBTU/sq. ft
year. It shows that the tall thin model is the worst formation to save energy.

The medium-medium model provides 40% saving energy more than the tall thin model, and the
energy efficiency of a short wide model is approximately 6% higher than that of a medium-
medium. It can be recognized that the competition of the most efficient building form is between
the medium-medium and the short wide which is very close, and the difference results between
the medium-medium and the short wide forms are small. The tall thin model distanced itself from
other models in terms of energy efficiency by almost 40 to 46%. The rest of the scenarios appear
in slightly different percentages but in the same order in terms of the most efficient energy model:
short wide, medium-medium, then tall thin.

(Figure 6.0) EUI of different masses. (In this chart, if the line between the tall thin result and
medium-medium result is ±25°, it means this chart is on the right scale because the difference
between these two results is 40% [1:2.5 ratio]. Also, if the rotation line between the medium-
medium result and short wide result in this chart is about ±4°, it is on the right scale because the
difference between these two results is 6% [1:16.67 ratio]).

40
28.67
27
40%
6%
0
5
10
15
20
25
30
35
40
45
Tall Thin Model
32ft x 32ft x 96ft (10 Stories)
(9.75m x 9.75m x 29.26m)
Medium-Medium Model
48ft x 48ft x 48ft (5 Stories)
(14.63m x 14.63m x 14.63m)
Short Wide Model
100ft x 100ft x 9.6ft (1 Story)
(30.48m x 30.48m x 2.926)
KBTU/SQFT YEAR
EUI of Differnt Masses
EUI Expected EUI Line For Other Masses
116

(Figure 6.1) Smooth expected EUI line (In this chart, if a straight line between the tall thin result
and medium-medium result is ±25°, it means this chart is on the right scale because the difference
between these two results is 40% [1:2.5 ratio]. Also, if the straight line between the medium-
medium result and short wide result in this chart is about ±4°, it is on the right scale because the
difference between these two results is 6% [1:16.67 ratio]).

By reviewing the conclusions, it can be assumed that the hypothesis is supported. The hypothesis
is that the short wide buildings offer greater energy conservation as compared to the tall thin
buildings when they are all in similar conditions in regard to materials, systems, controls, designs,
and specifications. The second hypothesis is also supported, and it states that the EUI results of
medium-medium (cube) buildings are among the EUI results of the tall thin and short wide
buildings. However, it should be noted that the EUI results prove that the difference between the
medium-medium (cube) and the short wide model is almost equivalent.

6.1.2 Scope of work

The similarities between the energy performance of the three residential different medium building
size forms; tall thin, medium-medium and short wide, are the mass volume, total floor area,
Window Wall Ratio (WWR), and plan aspect ratio. Also, all building elements have been
combined including the facade material, window glass, roof, construction material and system,
building function, heating, air conditioning, insulation, ventilation, curtains type according to the
building code of all the three cities. Also, the amount of electricity and gas consumption for
cooking, laundry, and other routine uses are united, and no type of renewable energy was used to
obtain electricity or heat water. The rate of financial cost for electrical and gas applications was
disregarded because the rate may change from time to time and place to place for several reasons
beyond the performance of the buildings or their natural environment. The thermal comfort zone
is determined to be between 70 and 75°F (21-24°C). The rest of the settings, for instance, lighting,
daylighting and how to calculate the internal heat were not changed from HEED sittings.
Tall Thin Model
32ft x 32ft x 96ft (10 Stories)
(9.75m x 9.75m x 29.26m),
Medium-Medium Model
48ft x 48ft x 48ft (5 Stories)
(14.63m x 14.63m x 14.63m),
28.67kBTU/sqft year
Short Wide Model
100ft x 100ft x 9.6ft (1 Story)
(30.48m x 30.48m x 2.926),
0
5
10
15
20
25
30
35
40
45
kBTU/sqft year
Smoth Expected EUI Line
117

All building energy options are taken from the US Building Energy Code. Building options have
been standardized from each city's building code by taking the highest building requirements from
each city; for example, the window glass type (Table 4.0). Three fixed locations, Los Angeles,
New York, and Las Vegas are added for each of the three selected models. Then, the value of an
additional variable was added from three additional variables, orientation, infiltration, and Light
Venetian Blinds, to test its effect on each building form in one of the three locations. For each
additional variable, there are three different values. The values of the orientation variable are ±0°,
-30°, and -45° slopes. The values of the infiltration variable are Sealed HVAC Ducts + Building
Air Barrier, 2.0 SLA/ 4.0 ACH, Verified Air Sealed + Quality Insulation Installation, 1.5 SLA/ 3.0
ACH, and Passive House Standard, 0.3 SLA/ 0.6 ACH. The values of the Light Venetian Blinds
variable are fixed mode, at 45°, closed mode, when the sun is on the window and indoors is above
comfort low, or 3°F below comfort high in winter, and last mode is automated with temperature,
at 45° or closed tight hourly when the indoor temperature reaches 3°F below comfort high.

6.2 Evaluation of the Methodology

The methodology idea is to test three models of the different forms but with equal massing volumes
and total floor areas, and to show which model is better in terms of energy conservation by making
numerous scenarios. In the first level of the methodology, at the beginning of the methodology,
the number of stories and the different length, width, and height dimensions of the three
variousforms of all models that were calculated to settle the total floor areas and massing volumes
of all models. The floor to floor height is installed to calculate the size fairly and correctly for all
models.

The WWR is fixed to have equal glass proportions in all models. Besides, the plan aspect ratio of
all models is adjustedby making it in a square shape as an attempt to make the results between the
three models equal. The rest of the designing building options in all models have been standardized
based on the building codes of each city and the US Building Energy Code. At the second level,
each of the three models is placed in three different cities in America; each one has a different
climate. In the third and final level, one of the three values from one of the three additional
variables has been chosen to test the validity of previous studies is placed in each scenario.

After that, 81 scenarios are simulated, and this should be done one by one. Nine scenarios in the
third level have been added to the models that do not contain cooling and heating systems to test
the internal temperatures of each of the nine scenarios in the second level. The results of all
scenarios are examinedand evaluated by the results' type, which are the EUI, hours of passive,
cooling and heating, indoor temperate, and energy and envelope performance results. Finally, all
scenarios' results for the three models are collected, evaluated and given a complete review. The
methodological idea is reasonably valid, but what is not calculated is that the three models now
have different roof and facade for each model. As well, it leads to another variation which is the
number of windows and the distance between them in each model to another model.

118

6.2.1 Improvement to current workflow

To improve the workflow would be possible by making the total floor areas of all different model
forms exactly equally. However, HEED restricts the user by using a grid network of 4x4 feet
squares, so the length and width dimensions of models must be valid on the division of 4 feet only.
Therefore, to improve the current work had to be an attempt to approximate the total floor area of
the three models, which made the total floor area of the tall thin model equals 953.6m2 (1,032
square feet) in the HEED grid network.

The total floor area of the medium-medium model equivalents 1070.25m2 (11,520 square feet),
and the total floor area of the short wide model is 929m2 (10,000 square feet). Also, because the
floor to floor height of the three models is set up already, 9.6 feet (2.93m), for a reason, the massing
volume of the three models cannot be uniform due to the different total floor areas of the three
models, which made the massing volume of the tall thin model equal to 2860.8m3 (101,028.2
cubic feet) (Figure 4.42). The massing volume of the medium-medium model totals 3210.75m3
(113,386.6 cubic feet), and the massing volume of the short wide model is 3021.72m3 (106,711
cubic feet) (Figure 4.45 and 4.48).

Next, the window sizes and spaces between each other in all models has been found to have some
problems. The WWR has been set up at 25% for all models. Furthermore, the windows in the three
models are distributed in a balanced way of each facade's story, and they are centralized in each
model’s story. Also, it has been set up that all windows should have the same aspect ratio, 1:1,
square shape. However, the only thing that could not be done was to make all windows in all three
models have the same width and height dimensions due to differences between the façade areas of
the three models, geometric reasons. Therefore, the roof area of the tall thin is less than the
medium-medium model, and the roof area of the short model is the largest between the tested
models.

Therefore, the windows cannot get the same surface area either in independently or totally, and
this also causes the different dimension between each window for each model. However, the
surface area of each window is approximated in all models. It found that the window surface area
for each window of all models is 16 square feet, 4x4 feet, will be the most suitable. More than 4x4
feet or less for all windows in all models will make the window condition, the spaces between each
window, in all models, look very wide or tight (Figure 4.11, 4.15, and 4.18).

6.2.2 Future work

First, this project can be used in other Building Energy Modeling (BEM) software tools because it
may give different results than the HEED results and other BEM tools can be designed with equal
total floor areas for different molding forms. Second, additional variables may also be added to
the current three additional variables at this project, for example, the facade material, window
glass, cooling and heating systems, or using the renewable energy technologies. Third, it can be
added more than three values for each additional variable. Finally, it can be added new models
with ranging scales, for instance, 25, 50, 75 and 100%, can be added to larger or smaller the current
models to test how the energy efficiency of the models will be at different scales. However, the
119

larger models must be done in another BEM tool because HEED cannot manage larger projects
than 14400 square feet (1,337.8m3).

6.3 Summary

In brief, the hypotheses are supported after comparing the EUI results of all models in different
cities when using the basic scenario, the first scenario of each model with its city. It was found that
the most energy efficient model is the short wide form in sharp competition with the medium-
medium form (cube). However, the tall thin form is exceptionally far from the competition because
it gave incredibly high results for energy consumption, unlike the medium-medium and short wide
forms. The energy efficiency of the short wide model is approximately 6% higher than the energy
efficiency of a medium-medium model. The energy efficiency of the medium-medium model is
almost more elevated than the energy efficiency of the tall thin model by 40%. Also, it has been
reviewed the determinants, constants, and variables of the work have been reviewed. The plan of
the methodology finds the logical approach to detect what the most building formation is to
increase building energy efficiency.

Moreover, the workflow is in line with the methodology. The workflow modifications are done
due to HEED limitations such as finding the nearest total floor area to minimize the impact of
different results of the building form parameter. Therefore, the total floor area of the tall thin model
is 953.6m2 (1,032 square feet). Also, the total floor area of the medium-medium model is
1070.25m2 (11,520 square feet), and the total floor area of the short wide model is 929m2 (10,000
square feet).

A problem has also been discovered that cannot be solved because of the geometrical determinants
that windows cannot be made equal in number, areas, and dimensions because each model contains
different facade areas even if the models have equal massing volume and total floor area. Since
WWR and the windows square shape have been fixed from the beginning, so window dimensions
cannot be selected randomly. However, the width and height dimensions of the window are chosen
at 4x4 feet because it is the most suitable dimensions to have almost the same distance between
the windows. However, it has been discovered that the window dimensions should be changed
slightly to make all models have the same WWR, 25%.

In the end, several ideas are given for future work, such as using a BME tool other than HEED.
Also, more different new values can be added to the additional current variables and put in new
variables. Additionally, constants can be changed.

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Abstract (if available)

Abstract The façade is a line between indoor and outdoor, which makes it one of the most significant topics in building science. It has been chosen to test the energy-efficient of the most basic common architectural building forms, tall thin, medium-medium (cube) and short wide building forms, that are using precast concrete façades with standard thermal comfort. This may help develop the precast concrete envelope market in the U.S. and make people more confident in precast concrete envelopes starting from the governments and architectural firms because usually wood, steel, stone and glass are used as a building envelope in America, but precast concrete envelopes are used more than any façade material in the Middle East. ❧ Three different residential building forms have been tested. The tall thin model dimensions are 9.75m × 9.75m × 29.26m (32ft × 32ft × 96ft), ten stories, and the medium-medium model has 14.63m × 14.63m × 14.63m (48ft × 48ft × 48ft), five stories. The short wide model is 30.48m × 30.48m × 2.93m (100ft x 100ft) × 9.6ft, one story. They have been designed by using the same US energy building codes and standards. Also, they have been used almost the same equal total floor area, ∼1000m² (10,764 square feet), massing volume, ∼3000m³ (105,944 cubic feet) plan aspect ratio, 1:1, and Window to Wall Ratio (WWR), 25%, at three diverse climate locations in the US, Los Angeles, New York, and Las Vegas, with an additional three variables, which are building orientation, ±0°, -30° and -45°, infiltration system, 2.0, 1.5 and 0.3 SLA/ 4.0, 3.0 and 0.6 ACH, and controlled blinds in three modes, fixed, automated with sun rays and automated with temperature, to find which precast concrete model saves the energy more by using a Building Energy Modeling (BEM) software tool, Home Energy Efficient Design (HEED). ❧ The results show in general the short wide model is the most energy efficient massing in all different conditions, which makes it first. Secondly, the cube-shaped model follows closely, which is 6% higher energy consumption than the short wide mass. Lastly, the tall thin building form with the precast concrete façade performs much worse. The energy consumption of the tall thin precast concrete façade in all conditions is 46% more than the short wide mass and 40% more than the cube mass. Usually, this ordinal is valid even though all the specifications and approximately the total floor area, massing volume, plan aspect ratio and WWR are the same, but the percentages may change a little bit, depends on the additional variables.

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Asset Metadata

Creator Allheedan, Fahad (author)

Core Title Energy performance of different building forms: HEED simulations of equivalent massing models in diverse building surface aspect ratios and locations in the US

School School of Architecture

Degree Master of Building Science

Degree Program Building Science

Publication Date 07/23/2019

Defense Date 05/06/2019

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag building form,concrete envelope,cooling,Energy Use Intensity (EUI),facade,Heating,HEED,indoor temperature,OAI-PMH Harvest,solar heat,thermal mass

Format application/pdf (imt)

Language English

Contributor Electronically uploaded by the author (provenance)

Advisor Noble, Douglas (committee chair), Choi, Joon-Ho (committee member), Konis, Kyle (committee member)

Creator Email allheeda@usc.edu,arch.fahad.note@gmail.com

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c89-185116

Unique identifier UC11660178

Identifier etd-AllheedanF-7575.pdf (filename),usctheses-c89-185116 (legacy record id)

Legacy Identifier etd-AllheedanF-7575.pdf

Dmrecord 185116

Document Type Thesis

Format application/pdf (imt)

Rights Allheedan, Fahad

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the a...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus MC 2810, 3434 South Grand Avenue, 2nd Floor, Los Angeles, California 90089-2810, USA