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Computer aided solar envelope design

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Computer aided solar envelope design

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Content COMPUTER AIDED SOLAR ENVELOPE DESIGN
by
Uen-Fang Patricia Yeh
A Thesis Presented to the
FACULTY OF THE SCHOOL OF ARCHITECTURE
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
MASTER OF BUILDING SCIENCE
August 1992
Copyright 1992 Uen-Fang Patricia Yeh
UM I Number: EP41429
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UNIVERSITY O F SO U T H E R N CALIFORNIA
THE SCHOOL O F ARCHITECTURE
UNIVERSITY PARK
LOS ANGELES, CALIFORNIA 90089-0231
13u., S.
'92.
^(43
37o$ C .
This thesis, w ritten b y
U e . n 7 F . a L n g . . Y e h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
under the direction o f h -e r . . .. Thesis C om m ittee,
an d a p p ro v e d b y all its m em bers, has been p re
sen ted to an d accepted b y the D ean o f The School
o f A rch itectu re, in partial fu lfillm en t o f the require
m en ts fo r the degree o f
Master of Building Science
THESIS COMMITTEE
— _
ACKNOWLEDGEMENTS
Professor Marc Schiler directed me during the early stage of my research
and helped clarify the topic and approach of my thesis. His continuing
encouragement and inspiration was really an essential support in accomplishing this
work.
j Professor Ralph L. Knowles gave me a very clear picture of a solar
j envelope concept through his definition and explanation. He also provided the
j direction of the entire research. He kindly allowed me to use his photos on my
thesis to further value the whole work. I appreciate his willingness to share
I thoughts and insights regrading to his latest research results on related subjects.
J I owe a substantial debt to Professor Douglas Noble and Karen Kensek for
their thoughtful and painstaking assistance in the preparation of this thesis. They
instructed me on how to effectively transform abstract ideas into writing, with
j supplements of graphics and charts. They reviewed my draft carefully and
| patiently, making corrections, giving suggestions. Without their devotion to the
f !
1
j entire process, this thesis would be impossible.
Professor Goetz Schierle has been very helpful since the very beginning. He
read the draft and made very helpful and clarifying advice. His cheerful
conversation always kept me confident.
Special thanks are to my friends Cheng-yu Ho, John Barry and James Lin,
who gave assistance and encouragement during the course of preparing this thesis.
Their advice eliminated the problems I encountered on the computer. Through
discussion with them, I also improved the syntax and clarify my topic.
Mr. John F. Carroll, president of Prenderast & Associates in Oregon, gave
me very helpful advice from the point of view as developer. Therefore, I can have
the opportunity to put the solar envelope in another light. Thanks to his valuable
time and information.
In the end, Ping-Hung Kuo deserves the most special appreciation. Thanks
to his thoughtfulness and understanding and by his recognition of my efforts, I felt
his support has been the greatest motivation behind the scenes.
iii
TABLE OF CONTENTS
I. LIST OF FIGURES
II. LIST OF TABLES
III. ABSTRACT
1. INTRODUCTION
2. HISTORICAL PERSPECTIVE
2.1 Growth of cities
2.2 Zoning and cities
2.3 Solar access zoning
2.4 Solar envelope
3. SOLAR ENVELOPE CONCEPTS
3.1 Solar access variables
13.1.1 Latitude
1 3.1.2 Julian day
j 3.1.3 Declination
1 3.1.4 Hour angle
J 3.1.5 Solar altitude
1 3.1.6 Solar bearing angle
i
13.2 Solar envelope additional variables
j
1 3.2.1 Cut-off time / start time and finish time
1 3.2.2 Site size and orientation
3.2.3 Boundary line
1 3.2.4 Boundary conditions
j 3.3 Definition of solar envelope for specified cut-off time without boundary
| condition
3.4 Definition of composite solar envelope without boundary condition
j 3.5 Definition of composite solar envelope with boundary condition
1 4. SIMULATION METHODOLOGIES OF THE COMPUTER
PROGRAM
4.1 Solar access calculation
4.1.1 Latitude
4.1.2 Julian day
4.1.3 Declination
4.1.4 Hour angle
4.1.5 Solar altitude
4.1.6 Solar bearing angle
4.2 Solar envelope for specified cut-off time without boundary condition
calculation
|4.3 Composite solar envelope without boundary condition calculation
j 4.4 Composite solar envelope with boundary condition calculation
1 4.5 Changing variables
H
1 4.5.1 Changing the latitude
26
27
27
29
30
32
34
36
36
36
37
38
38
38
39
44
46
48
48
4.5.2 Changing the site size
4.5.3 Changing the surrounding street
4.5.4 Changing the cut-off times
1 4.5.5 Changing the boundary condition
1 5. APPLICATIONS
5.1 Solar envelope zoning
j
1 5.2 Plan unit development
1 5.3 Grouping buildings
1 5.4 Shadow control
i
1 6. FUTURE WORK
1 7. CONCLUSION
1 7.1 Objective of study
j 7.2 Use of SolVelope
1 7.3 Summary
t
!
t
APPENDIX A
1. SolVelope output
49
50
53
54
55
57
58
60
62
65
72
72
73
74
75
REFERENCES 81
LIST O F FIGURES
Fig. 1-1: Mesa verda, Colorado, cliff face
From the book " Sun Rhythm Form " p . 11
2
Fig. 2-1: Tall buildings in cities
From the book " The Skyward Trend of Thought " p. 35
5
Fig. 2-2: City’s sky outline
From the book " Sun Angle for Design " p. 3
6
Fig. 2-3: Solar Shade Control Act.
From the book " Solar Access Law " p. 41
11
Fig. 2-4: Solar envelope development constraint in existing neighborhood
From the book " Solar envelope concepts " p. 96
12
Fig. 3-1: Solar envelope example 16
Fig. 3-2: Latitude 17
Fig. 3-3-1: Declination is the earth axis tilt angle relate to the sun’s position 18
Fig. 3-3-2: Declination is the earth axis tilt angle relate to the sun’s position 19
Fig. 3-3-3: Declination (degree) / Day of year 19
Fig. 3-4-1: Plan view of world from north pole / One hour later the earth
rotation is 15 degree
20
Fig. 3-4-2: Hour angle (degree) / Hour 20
Fig. 3-5: Solar access 21
Fig. 3-6: Hourly altitude at same bearing angle 26
v i i
Fig. 3-7: Site variables 26
Fig. 3-8: Boundary condition 28
Fig. 3-9: Defining the lowest height through all the hours for solar 29
envelope height
Fig. 3-10: Composite plane for solar envelope 31
Fig. 3-11: Boundary conditions 33
Fig. 4-1: Flow chart of the program 35
Fig. 4-2: Site variables 39
jFig. 4-3: Solar envelope height calculation 42
it
»Fig. 4.4: Solar envelope height at each hour 43
i
! j
|Fig. 4-5: Composite envelope 45
|Fig. 4-6: Variables for boundary condition 46
|Fig. 4-7: Composite envelope with boundary condition on each direction 47
!
jFig. 4-8: Solar envelope at different latitudes 48
!
jFig. 4-9: Different site length and width 49
|Fig. 4-10: Different orientation solar envelope 50
Jpig. 4-11: Solar envelope at different east and west street width 50
I
jFig. 4-12: Solar envelope at different north and south street width 52
f
i
iFig. 4-13: Different cut-off time in the summer 53
!
|
jFig. 4-14: Different north boundary height envelope 54
|
|Fig. 5-1: Solar envelope zoning 57
Fig. 5-2-1: Solar envelope zoning 58
v i i i
Fig. 5-2-2: Plan unit development 59
Fig. 5-3: Parking structure on the north block 60
Fig. 5-4: Shopping mall on the east block 61
Fig. 5-5-1: Solar envelope restricting shadow on specific site 63
Fig. 5-5-2: Clarifred diagram showing street grid and solar envelope 63
restricting shadow on specific site
Fig. 6-1-1: Future SolVelope user interface: case A 67
Fig. 6-1-2: Future SolVelope user interface: case B 69
ix
Table 1:
Table 2:
Table 3:
Table 4:
LIST O F TABLES
Solar angle / March 21, 35 N latitude 22
Solar angle / June 21, 35 N latitude 22
Solar angle / September 21, 35 N latitude 23
Solar angle / December 21, 35 N latitude 23
x
ABSTRACT
| This investigation involves developing a computer program intended to aid
| in the calculation and visualization of the solar envelope based on many design
parameters.1 The program will include altitude and azimuth calculations for any
latitude, date, time, and will include solar envelope calculations for both sites with
J boundary conditions and without boundary conditions. The computer program for
I the solar envelope generation has been designed to have text input and three
dimensional graphic output. The text input is intended to get user’s input directly
I
j and clearly. The three dimensional graphic output is intended to help visualize and
! understand the solar envelope.
The concept of solar envelopes was first developed as a framework for
architecture and urban design at the University of Southern California (USC) over
the period 1969 to 1971 by Prof. Ralph L. Knowles. In 1976, a directed research
seminar was initiated by Prof. Knowles at USC to further develop the envelope
concept as a public zoning policy. Solar envelope is a building volume limit that
will not cast shadows on surrounding buildings at specified times. Therefore it
must be constructed from data based on the sun’s movement (time) relative to the
j location and geometry of a site (space). The solar envelope is thus a constructed
i
[ synthesis of time and space.
1 Ralph Knowles, Solar Envelope Concepts, 1980, p.2, Solar Energy Research Institute, Golden,
Colorado
x i
Being able to calculate solar envelopes is one step towards re-affirming the
positive role and form generation capabilities inherent in sunlight. The relationship
between solar access and quality of life will hopefully move us towards the
emergence of solar rhythm as a design strategy.
1. INTRODUCTION
The sun is fundamental to all life. It is the source of our vision, our
warmth, our energy, and the rhythm of our lives. Its movements inform our
perceptions of time and space and our scale in the universe. Without the sun, we
face uncertainty and disorientation. The purpose of this study is in response to the
sun’s rhythm, solar access, building form, and the urban environment.
Initial architecture was a shelter to keep human beings from nature
harassment. Shelters had to respond to sunlight to achieve maximum comfort and
safety. Its location and shape was then selected accordingly.
Through time and experience people have learned how to find
and build shelters. By using the sun’ s energy and position, people find
ways to make a better living spaces, this is human instinct. The location
and form o f buildings at Mesa Verde, Colorado, is a good ancient
example o f providing residents with year round comfort. The pueblo
demonstrates a remarkable ability to mitigate extreme environmental
temperature variations and respond to the seasons and the time o f day.
The primary adaptation o f the pueblo to the changing solar conditions
is in its location. The settlement is sited in a large cave that faces
south, and the built structures are nestled within. The brow o f the cave
admits warming rays from the low winter sun but shields the interior o f
the cave from the rays o f higher altitude and more northern summer
sun. Not only the orientation o f the cave itself but the juxtaposition o f
the structures within it are responsive to the dynamics o f solar
movement. The interior structures stay within the summer shadow line,
and they are arranged so that one structure steps up from another
toward the back o f the cave. It is thus the location o f the cave itself and
the siting o f structures within the cave that ensured the comfort o f the
pueblo dwellers. Because o f the orientation, the insolation on the cave
1
during the winter day is equivalent to that o f a summer day. The
performance o f buildings within the cave is more effective as a solar
collector in winter than in summer, providing winter heat and summer
coolness with remarkable efficiency. The seasonal adaptation is
complemented by the pueblo’ s response to a daily rhythm as the sun
moves from the eastern to the western sky, casting the morning rays
inside the west end o f the cave and twilight rays inside the east end.
The thermal mass o f the cave itself, as well as the structure o f
buildings within, helped to mitigate extreme daily variations, but the
main adaptation fo r comfort may be best understood in the rhythms o f
people’ s lives (Fig. 1-1 )2 .
summer
winter
S N
Fig. 1-1: Mesa verda, Colorado, cliff face
The sun’s rhythm is recognized in all natural processes. It appears in our
behavior and in our feelings about the world around us. When our environment
j pulses in natural time, we seem to know and understand it. When we are isolated
2 Ralph Knowles, Sun Rhythm Form, 1980, p. 11, The Massachusetts Institute of Technology,
Massachusetts
from natural recurrence, when we cannot feel natural tempos, we lose contact with j
j a basis of our perceptions. Solar access has recently come into focus as a topic of j
j discussion in the United States because more and more we are looking at the sun as
a source of energy. Solar access has therefore become a legitimate area of public
policy, in which the aim is to regulate how and when neighbors may shadow one
another.3
F .
I
The use of time as a determinant of space carries with it a whole set of j
! |
questions that have not been raised since we were an agricultural people concerned j
j with the sun as source of life. How the field performs is related to its time-space j
J exposure. The responses to time and space are again critical to development in j
J order to take full advantage of the sun as a resource. How we want our land and |
1 buildings to perform requires that we add time to our definition of urban space. |
!
! Solar zoning is one approach as a response to balancing the needs of growth I
j
and development with the quality of life issue of access to sunlight. Professor I
i
Ralph Knowles developed the concept of a solar envelope, a building volume limit |
1 that will not cast shadows on surrounding buildings at specified times. Since the j
J early 1970’s, he has been testing this concept in upper division design studios at |
' I
the School of Architecture at the University of Southern California. ;
\ All the solar envelope calculations in the USC design studio were done by i
| I
| hand. Students applied the solar altitude and azimuth for a particular site (latitude) j
I i
!
j _________________________ j
j 3 Ralph Knowles, Sun Rhythm Form, 1981, p.8, The Massachusetts Institute of Technology Press,
j Massachusetts I
\ to graphically generate the solar envelope. Then, they made a physical model j
1 !
I I
I accordingly and used it as a reference to assist in their building design. With use of j
this physical model and a sun-simulating machine4, they could actually see the j
effect of the sun’s movement on their buildings and on the neighborhood. The
entire process of generating a solar envelope usually took about 30 working hours
for a simple assignment and much more for a complicated one. Since it is a time-
! consuming task, students did not have the opportunity and willingness to explore '
\ • j
I S
the other issues regarding the concept. Therefore, their understanding on this topic ’
i was often not thorough and sufficient. For most practicing architects, this process j
| j
I i
of generating the solar envelope would be too long and cumbersome.
To help resolve this problem, several aids could be developed to assist in |
j the generation of the solar envelope. One useful tool might be a series of tables to j
i i {
I estimate the dimensions and volume of the envelope. Another alternative would be j
an interactive computer program that could calculate and draw the envelope for a
given site size, orientation, and location. !
I
|
The advantage of a computer program is its speed of handling data. After j
s
j
the required data are input, it can give immediate response. This feature makes i
possible a variety of research. The widespread use of computers today can help
publicize the idea. These advantages make computer programs a perfect solution to
meet this need.
i ---------- ...
\
| 4 The sun simulating machine is a mechanical device used to simulate the movement of the sun by using
an artificial light source and a scale physical model.
2.HISTORICAL PERSPECTIVE
2.1 Growth of cities
Cities are the places where people get together, work, and consume. With
better opportunities of employment and education, cities attracted more people to
move in and stay to seek a better life and share public utilities. To accommodate the
new population, more buildings were constructed for them to work and live in.
Therefore, public open space was disappearing, and the number and height of
buildings were increasing (Fig. 2-1).
Fig. 2-1: Tall buildings in cities
5
As buildings overflow the cities, people start to react. In 1916, residents of
New York City were aware that they were losing their sky, sun, air, and space
because the city was growing without any rules. Parks disappeared. Tall buildings
blocked out the sky. They figured they were paying a price for the city’s overgrowth.
Therefore, people started talking about how to prevent this situation getting worse.
Cities need to grow. But they have to grow with intentional control. The
emergence of zoning is in response to this need (Fig. 2-2).
Fig. 2-2: City’s sky outline
6
2.2 Zoning and cities
J Zoning is a public policy to effectively control growth of cities, and the
I ultimate purpose is to guarantee quality of our living environment. It specifies use
of land, maximum allowable building height, mass and thus the density of cities. j
j Zoning came into effect in New York City in 1916. Since that time it has become j
I
one of the most extensively used means of controlling the urban environment in the j
nation. I
Cities developed their own policy based on respective needs, giving
characteristics to each city. For example, two sets of New York zoning laws from
1916 and 1961 resulted in two characteristic building types: the ziggurat setbacks
produced by the earlier law and the blocky base and shaft or the free-standing I
’ I.
!
tower of the revised version. Since zoning laws can control the building
| placement, height and shape, the city image can be pictured even before buildings j
j are actually built. j
| |
j Citizen’s desires usually shape the zoning policy. People in San Francisco |
have specific concerns about historical buildings and sunny parks, air, sky line of !
i
the city, building density, feeling of walking on the street, building elevation, j
I shadow and so on. These opinions were considered and adapted by the government j
i
of San Francisco in a detailed and decisive building code. J
5 Ada Louise Huxtable, H ie Tall Building Artistically Reconsidered , 1984, p. 102, Pantheon Books, J
New York
7
2.3 Solar access zoning
Solar access is one of the items protected by zoning policy to insure the
quality of our living environment. In 1968, the American Society of Planning
Advisory Service proposed the following, demonstrating the desire to guarantee
solar access.
1. In new developments or large scale redevelopment, the simplest way
to protect solar access is to require such large lots that structures
cannot cast shadows across lot boundaries during hours when solar
energy is to be protected.
2. Height limits will be an important element o f any solar access law.
Most existing height regulations, however, will not be adequate. In
areas zoned fo r single family residences, fo r example, a uniform thirty-
five-foot height limit is fairly common. One analyst notes that "The
height limit is the same on a 50-foot lot with 5-foot side yards as on
two-acre lots with 25-foot side yards, apparently on the theory that the
well-to-do require more light and air than the rest o f the population.6
Height limits would appear to afford a considerable measure o f solar
access protection against shadow cast by structure.
3. The definition o f grade is also important to solar access
protection. The height should relative to the grade along the front or
street side. I f the lot slopes down away from the street, a taller building
is permitted by the street level reference. On lots that slope down
toward the north, a street side reference point may mean that more
structure are severely shaded than necessary revise, their definition o f
grade to help achieve the desired level o f solar access protection.
4. A community should also examine and consider changing its building
setback requirements from front, back, and side lot lines. For solar
access purposes, it makes sense to allow structures to be sited more
flexibly than allowed under most zoning regulations. In areas that are
6 Frederick H. Blair, Jr., Height Regulation in Residential Districts, 1968, p.2, American Society of
Planning Advisory Service Report, Chicago
already developed, the few new structures that are built may appear out
o f character with the neighborhood if their placement is very different
from that o f surrounding structures. The solar access benefits o f new
setbacks may be minimal unless there is substantial redevelopment
or expansion o f existing structures.
5. FARs have both advantages and disadvantages with regard to solar
access controls. Their disadvantages are that the height and exact siting
o f a structure cannot be predicted, making it difficult fo r neighbors to
plan their solar energy systems. It may be possible to modify FAR
controls to encourage or mandate the accommodation o f access needs,
by allowing density bonuses in exchange fo r maximizing solar access.7
If the building height and shape can be controlled, an appropriate amount of
sunlight in the city for a particular time and space can be insured. The shadow
control policy of San Francisco is an application of this approach. This policy does
not allow new shadow on public open space. New projects need to be developed
under this limit to get a construction permit. Though it greatly limits the allowable
building heights in adjacent blocks, the government gives a higher FAR as a bonus
to encourage the accommodation of access needs. This compensation also obtains
balance between protection and development.
Traditional zoning tools and procedures that can be modified to protect
solar access include density zoning; height, grade, and setback rules; a floor to
area ratio (FAR) controls.
Under the most familiar type of zoning, each district is controlled by a
fixed set of use, height, setback, density, and building coverage regulations. It is
7 Peter Pollock, Solar Envelope Zoning - Application to The City Planning Process, 1980, p.21,
Solar Energy Research Institute, Golden Colorado
Gail Boyer Hayes, Solar Access Law - Protecting Access to Sunlight For Solar Energy Systems,
1979, p.42, Environmental Law Institute, Washington, DC
9
not recommended that localities rely heavily on such rules for solar access
protection in developed areas because the same numbers (for heights, setbacks,
etc.) are applied uniformly throughout each district so that little allowance is
ordinarily made for unique site characteristics or for the relationship of a given
parcel to nearby development. For example, the direction in which land slopes will j
be critically important to solar access. A building on a hilltop or one on a site that
slopes down to the south will often enjoy good solar access regardless of activities |
on adjacent land. But a structure on a lot sloping to the north may be shaded unless
severe development restrictions are put on land to its south. However, since many
communities developed around, and continue to rely upon, traditional zoning j
I
districts, they should seek ways to adapt them to this new purpose. This could be a
I
new way to save energy and build up the building volume limits to protect the j
i
environment and make a natural image for the city.8 j
1
In 1972, the oil embargo caused a universal attention to use natural energy. J
s
The economical and environmental cost of conventional fuels brought solar energy j
as an alternative energy source for heating and cooling. In 1981, The Institute of
Governmental Affairs proclaimed the Solar Shade Control Act (Fig. 2-3) to
guarantee solar access to solar collectors. Solar energy utilization requires public |
guarantees that all property owners have sufficient solar access. This act protects
I
existing solar collectors by limiting development of the site’s neighbors. The Solar
8 Gail Boyer Hayes, Solar Access Law - Protecting Access to Sunlight for Solar Energy Systems, j
1979, p.41, Environmental Law Institute, Washington, DC
10
Shade Control Act is given the sky limit to the neighbors for protecting the solar
collecter on it’s own property. Solar access law is needed for protecting access to
sunlight for solar energy systems.
possible height of neighboring
development
ZONE C
protected building
ZONE 01
ZONE C
I
!
Fig. 2-3: Solar Shade Control Act.
12
2.4 Solar envelope
The solar envelope (Fig. 2-4), by definition, is the largest volume within
which the building will not overshadow the adjacent properties.
Fig. 2-4: Solar envelope development constraint in existing neighborhood
This idea was first developed by Professor Ralph L. Knowles at the
University of Southern California (USC) over the period 1969 to 1971. In 1976,
Knowles began a directed research seminar at USC to further develop the concept
as a public zoning policy. In 1977, an undergraduate design studio was directed by
Knowles and Richard D. Berry to design buildings within envelope constraints.
The results of research were published in Energy and Form , Solar Energy,
Building, and the Law, and Sun Rhythm and Form.
13
The basic difference between the solar envelope and the solar access zoning
is twofold: (1) the former constrains development on a designated property to
protect the surroundings instead of restricting the development surrounding the
property; (2) it can geometrically describe the envelope instead of numerically.
Theoretically, the solar envelope is an excellent tool to insure that sufficient
sunlight is shared by all the residents. But it indirectly restricts the allowable floor
areas for construction and limits the design freedom to a specific maximum
volume, the solar envelope is not broadly accepted as a practical zoning tool.
t
The Solar Energy Research Institute had done research on the solar
envelope zoning for the city of Los Angeles in 1980. They tried to apply the solar
envelope idea as a zoning law. What follows are some of the possible solar
envelope zoning laws proposed by the Solar Energy Research Institute.
1. Rules fo r generating solar zoning envelopes must be sufficiently
generalized to accommodate any development proposal and to
guarantee solar access to all existing buildings that might surround any
parcel.
2. Once a solar envelope has been determined fo r a specified
development land parcel, the zoning envelope is defined, limiting future
construction height, bulk and setbacks: in effect, no building or
landscaping element may extend outside the envelope.
3. To protect solar collector plates that might in the future be placed on
any nearby roof, the solar envelope fo r a land parcel cannot extend
above the roof parapet o f any existing building during the specified
hours o f the day.
4. Parcels o f land containing only temporary structure or having
structures whose bulk is 10% or less o f the allowed F.A.R. may be
treated as vacant parcels fo r purposes o f establishing a solar envelope.
14
5. I f a development parcel adjoins one or more vacant sites, then a
single envelope may be constructed under the assumption that fire walls
would be built at the common property lines when new buildings
occurred.
6. Walls o f surrounding buildings that serve as fire walls or that have
no significant windows in them have little or no potential fo r utilizing
solar irradiation, and such wall may be totally shaded by a solar
envelope.
7. Walls o f nearby buildings that function as window walls or that have
window openings that exceed 25% o f the wall area may be partially
shaded by the solar envelope so long as no more than one-third(33%)
o f the wall is shaded during the specified hours o f any day o f the
year.
8. I f a development parcel has nearby vacant land parcels located on
the opposite side o f a public right-of-way (a street or alley), then the
vacant parcels shall be treated as if they had buildings on them (which
they will have in time). Any hypothetical future building on the vacant
land must necessarily fit within its own solar envelope; hence, generate
the solar envelope fo r the vacant parcel and assume that a fu ll height
widow wall will eventually be built on the property line that fronts on
the right-of-way. Under this condition, the solar envelope fo r the
develop parcel may shadow one-third o f the assumed window wall.
However, if a solar envelope cannot be determined fo r the vacant
parcel, then the envelope fo r the develop parcel may cast a shadow on
the bottom 20 feet o f the hypothetical wall.
9. I f the walls or roof o f an existing low building are shadowed to a
greater extent than what is imposed by an intervening solar envelope,
then the solar envelope may be raised vertically until its shadow impact
equals but does not at any time exceed the existing tall building’ s
impact. In general, the increase in the envelope height will be
proportional to the ratio o f horizontal distances between shaded
building and the solar envelope and between shaded building and the
tall building which is producing the shadow.9
9 Peter Pollock, Solar Envelope Zoning - Application to The City Planning Process, 1980, p.24,
Solar Energy Research Institute, Golden Colorado
15
It is learned from the preceding paragraph that the solar envelope can still
be an accepted zoning tool if it is adapted to reality. For a given site, the latitude,
hour angle, solar altitude, and solar bearing angle are fixed. The boundary
condition and cut-off times are flexible and can be adapted to fit the planning
commission’s intentions.
16
3.SOLAR ENVELOPE CONCEPTS
It was learned from the previous chapters that the solar envelope is a solar
zoning tool to help conserve energy and to improve the quality of life by guaranteeing
access to sunlight during certain hours of the day. This chapter will further explain
the concept behind the solar envelope definition and investigate its formation.
The solar envelope (Fig. 3-1), as it is conceived in this work, is a container j
to regulate development within limits derived from the sun’s relative motion to a]
|
specific site and set of boundary conditions. Any development within this container j
would not cast shadows on designated surroundings during critical periods of the day.
The envelope is therefore defined by the passage of time and by the constraints of
properties. The solar envelope is a space-time construct. Its spatial limits are defined
by the parameters of land parcel size, shape, orientation, topography, latitude, and the
urban context. Its time limits are defined by the hours of each day and season for i
!
which solar access is provided to the land parcel.1 0 j
i
I
Fig. 3-1: Solar envelope example: views from S.W. and N.E.
1 0 Ralph Knowles, Solar Envelope Concepts, 1980, p.2, Solar Energy Research Institute, Golden,
Colorado
17
3.1 Solar access variables
Complete understanding of solar positioning is necessary for reasonable
solar design and climatic response. The time data for constructing a solar envelope
is derived from the perceived movement of the sun from one celestial region to
another. This movement is defined by a daily path, from east in the morning to
west in the afternoon, and by seasonal path, from south in the winter to north in
the summer. The sun’s relative position on the sky is dependent on the time of
day, day, month, year (very negligible) and viewer’s latitudinal location. Two
angles are used to define the position of the sun relative to a spot on the earth:
altitude and bearing angle. By using the sun’s position angle, we can define a
building envelope to control shadows; then we can set the shadow position and
calculate the solar building envelope.
3.1.1 Latitude
Latitude is the distance north or south of the equator measured in degrees.
The poles are 90 degrees. North latitude is a positive number; the south latitude is
a negative number (Fig. 3-2).
latitude
Fig. 3-2: Latitude
18
3.1.2 Julian day
The Julian day is the number of days since the first day of the year. For
example, March 21 has a Julian day of 80 days.
3.1.3 Declination
The path of the earth around the sun is a slight ellipse, barely
distinguishable from a circle. As the earth orbits the sun, it rotates once a day on
an axis that extends from the North Pole to the South Pole. This axis is tilted
23.47 degrees from a vertical to the plane of the earth’s orbit around the sun.1 1
The declination is a measure of the earth axis tilt angle relative to the sun’s
position (Fig. 3-3-1, Fig. 3-3-2, Fig. 3-3-3).
Fig. 3-3-1: Declination is the earth axis tilt angle relative to the sun’s position
1 1 Edward Mazria, The Passive Solar Energy Book, 1979, P. 11, Edward Mazria.
March
December
September
19
— j
Dec t I nat I on
s= o C d e g r e e } Dec I i nat. i on
- 90-66.53
= 23 . 47Cdegree;
December
Sun
Dec I Inat!on
= □ C d e g r e e p
Fig. 3-3-2: Declination is the earth axis tilt angle relative to the sun’s position
o
o
L .
o»
9
T >
C
o
o
c
o
9
O
ju#r 21
Jra 2 1
Day of yeor
Aug. 2>
Fig. 3-3-3: Declination (degree) / Day of year
3.1.4 Hour angle
The hour angle is an angular distance that the earth has rotated since
midnight. Since one full rotation of the earth is 360 degree, the earth rotates 15
degrees for each hour of the 24 hour long day (Fig. 3-4-1, Fig. 3-4-2).
20
15
Start time. One hour later.
Fig. 3-4-1: Plan view of world from north pole
/ One hour later the earth rotation is 15 degree
400
©
© 200
u >
c
o
so
0
2 4 6 10 12 14 I S 18 20 22
Hour
Fig. 3-4-2: Hour angle (degree) / Hour
i
j
i
3.1.5 Solar altitude !
The term altitude refers to the angle of the sun on the sky vault, measured
up from the horizontal earth-plane. Altitude is the sun’s position at elevation view.
Solar altitude sets the length of a shadow for a particular bearing angle. It also sets
the height of the solar envelope for a particular time (Fig. 3-5).
21
3.1.6 Solar bearing angle
The bearing angle is the position of the sun on the horizontal earth-plan
measured from south. It is the sun’s position in plan. Bearing angle for clockwise
.
from south is positive value, for counter-clockwise from south is negative value. I
Bearing angle is negative 90 degree on the true east, and it’s positive 90 degree on
the true west. Solar bearing angle decides the shadow direction. Given the latitude
I and bearing angle, the shape and height limit for the solar envelope can be
calculated. Set the shadow edge on the boundary line and then use the solar altitude
and bearing angle to find the height of the solar envelope volume (Fig. 3-5, Table-
1,2,3,4).
North
altitude
West
East -------
^ West East
South
North,
West<^~
North
— East
bearing angle
West
East
bearing angle
South
Fig. 3-5: Solar access
22
Table 1: Solar angle
March 21, N 35 degree latitude
Hour Altitude Bearing Hour Altitude Bearing
1 am -52.68 -154.73 1 pm 51.92 24.81
2 am -45.51 -134.48 2 pm 44.86 44.86
3 am -35.68 -119.48 3 pm 35.11 59.81
4 am -24.43 -107.98 4 pm 23.92 71.33
5 am -12.48 -98.40 5 pm 12.00 80.93
6 am -0.23 -89.67 6 pm -0.23 89.67
7 am 12.00 -80.93 7 pm -12.48 98.40
8 am 23.92 -71.33 8 pm -24.43 107.98
9 am 35.11 -59.81 9 pm -35.68 119.48
10 am 44.86 -44.86 10 pm -45.41 134.48
11 am 51.92 -24.81 11 pm -52.68 154.73
noon 54.60 0.00 12 pm 235.40 180.00
Table 2: Solar angle
June 21, N 35 degree latitude
Hour Altitude Bearing Hour Altitude Bearing
1 am -29.84 -164.11 1 pm 72.58 52.48
2 am -25.00 -149.59 2 pm 61.53 74.21
3 am -17.65 -137.10 3 pm 49.43 85.93
4 am -8.48 -126.55 4 pm 37.16 94.52
5 am 1.93 -117.54 5 pm 25.01 102.09
6 am 13.19 -109.56 6 pm 13.19 109.56
7 am 25.01 -102.09 7 pm 1.93 117.54
8 am 37.16 -94.52 8 pm -8.48 126.55
9 am 49.43 -85.93 9 pm -17.65 137.10
10 am 61.53 -74.21 10 pm -25.00 149.59
11 am 72.58 -52.48 11 pm -29.84 164,11
noon 78.45 0.00 12 pm 211.55 180.00
23
Table 3: Solar angle
September 21, N 35 degree latitude
Hour Altitude Bearing Hour Altitude Bearing
1 am -52.49 -154.85 1 pm 52.11 24.93
2 am -45.35 -134.65 2 pm 45.02 45.02
3 am -35.54 -119.66 3 pm 35.25 59.99
4 am -24.30 -108.15 4 pm 24.05 71.51
5 am -12.36 -98.57 5 pm 12.12 81.10
6 am -0.12 -89.83 6 pm -0.12 89.83
7 am 12.12 -81.10 7 pm -12.36 98.57
8 am 24.05 -71.51 8 pm -24.30 108.15
9 am 35.25 -59.99 9 pm -35.54 119.66
10 am 45.02 -45.02 10 pm -45.34 134.65
11 am 52.11 -24.93 11 pm -52.49 154.85
noon 54.80 0.00 12 pm 235.20 180.00
Table 4: Solar angle
December 21, N 35 degree latitude
Hour Altitude Bearing Hour Altitude Bearing
1 am -72.58 -127.53 1 pm 29.85 15.89
2 am -61.53 -105.80 2 pm 25.00 30.41
3 am -49.43 -85.93 3 pm 17.65 42.90
4 am -37.15 -85.48 4 pm 8.49 53.45
5 am -25.01 -77.92 5 pm -1.93 62.46
6 am -13.19 -70.44 6 pm -13.19 70.44
7 am -1.93 -62.46 7 pm -25.01 77.92
8 am 8.49 -53.45 8 pm -37.15 85.48
9 am 17.65 -42.90 9 pm -49.43 85.93
10 am 25.00 -30.41 10 pm -61.53 105.80
11 am 29.85 -15.89 11 pm -72.58 127.53
noon 31.56 0.00 12 pm 258.44 180.00
2 4
3.2 Solar envelope additional variables
3.2.1 Cut-off time / start time and finish time
Cut-off time is the desired hours to protect solar access to the surroundings.
From the point of view of energy conservation, because the solar collectors
need direct exposure to the sun, the most desired hours would be about three hours
before and after noon. Therefore, the cut-off time for Los Angeles is usually 10
am to 2 pm in winter and about 9 am to 3 pm in summer. But the selection of cut
off time also depends on the latitude. For example, the cut-off time for Australia
would be different from that for Los Angeles. Two hours of direct sunlight in
Australia might be adequate for the solar collectors instead of four hours in Los
Angeles.
The cut-off time is a very flexible variable when quality of life is the major
concern. The comfort zone of people in different locations varies with the latitude
and the local climate. The sunlight of noon might be very desired in Oregon, but
not very welcomed in India. In addition, personal preference is probably an
influential factor.
Once useful periods of solar access are defined, it is important to consider
their effect on the geometry of the solar envelope. An obvious and somewhat
frustrating fact about solar envelopes is that the longer the period of solar access,
the move volumetrically constrained the envelope. More simply put, less time
means more volume; more time means less volume. This, of course, is because the
sun’s angle defines the slope of the envelope. Early morning and late afternoon sun
25
I angles are relatively low, while midday angles are steeper, at all seasons of the
j year. Hence, on a daily basis, progressively increasing the hours of solar access
J will set cut-off times that provide progressively less and less building volume under
1
the envelope.
Determining exactly what cut-off times might be used, then will depend not
only on desired insolation but also on how much building volume is required to
accommodate development needs. To a designated site, cut-off time might be the
most flexible factor to determine the envelope volume. Some comparisons are
useful to clarify this inverse space and time relationship, which is unique to the
solar envelope (Fig. 3-6).1 2
|
i
I
1 2 Ralph Knowles, Sun Rhythm Form, 1981, p.61, The Massachusetts Institute of Technology.
Massachusetts
2 6
__________________ _J
A".
8 am 9 am 10 am 11 am noon
1 pm 2 pm 3 pm 4 pm 5 pm
Fig. 3-6: Hourly altitude at same bearing angle: showing effect of low early
morning and late evening on possible building volume
3.2.2 Site size and orientation
Site size is defined by its length and width. The orientation is the number of
degree off from north (Fig. 3-7).
surround i ng street
___________ r.
c
te
site length
street orientation
Fig. 3-7: Site variables
27
3.2.3 Boundary line
Boundary lines may be surrounding streets, legal property lines, or any
other constraints chosen for the definition of the edge of the site. The program
currently examines four sided sites. The boundary line had been define as the
shadow location. In this program it allow the shadow on the surrounding street, it
will only protect the sun light from the neighbors but not the streets.
3.2.4 Boundary conditions
The boundary condition is used to respond to the neighbors of the solar
envelope itself. When it’s necessary, the solar envelope can rise up depending on
the height of the building type on that boundary line. The boundary height is add
to the solar envelope height. For example, if a fire separation wall from a
historical building occupies one edge of the site, and there is no opening or
collector on that wall, the envelope may be raised to cover the wall (Fig. 3-8).
boundary he i
/ 1 -------------
ght-
S i te
Fig. 3-8: Boundary condition
3.3 Definition of solar envelope for specified cut-off time without boundary
conditions
start time, and finish time. On this particular condition, we need to calculated all
the solar angles to define this solar envelope. First we need to calculate all the
i
solar access angles in this particular time range (Fig. 3-9), and then calculate the I
i
solar envelope heights based on where the shadow should stop. The height of the j
i
j
solar envelope is then the lowest one at each point on the site from which would j
j cast shadow beyond the boundary lines.
i
j Choice of the date, start time, and finish time for the solar envelope will
depend on the site location and any special desires. Winter and summer solar
envelopes will be used differently in different weather. Envelopes with different
cut-off times can be based on the use of the building because in some condition j
people might use some particular hour envelope. For example, sunlight of 2 to 4 j
pm is needed for a hotel swimming pool, then the building has to follow the j
I I
responding envelope. j
Fig. 3-9: Defining the lowest height through all the hours for solar envelope height
29
The single day solar envelope is defined by the given latitude, month, date,
hour #1 hour #2 hour #3 hour #4 envelope height
3.4 Definition of composite solar envelope without boundary condition
From the point of view of energy, the most critical date of the year for both
water and space heating is December 21, the winter solstice, when the sun is
lowest in the sky. For a solar collector oriented due south, the most critical time of
day for maximum heat gain is between the hours of 10 am and 2 pm. Thus, a
logical sky space for most solar collectors in California and the Northern
I 1
Hemisphere is the space defined by the path of the sun between 10 am and 2 pm j
on December 21, when the sun is the lowest, and between 9 am and 3 pm on June J
I ' i
| 21, when the sun is the highest.1 3 j
i
I
It is essential to compare transformational groups from different seasons to
I complete a final envelope. For example, a summer envelope is often larger than a
j
winter envelope because the summer sun appears higher in the sky. Hence, a j
composite of the two will probably look more like the winter envelope because it is
I
lower and contains less volume.
There is no guarantee that cut-off times selected for purposes of energy
conversion and quality of life will necessarily produce envelope shapes. In general, <
i
I
it is more convenient to set cut-off times that produce simple envelope shapes j
(Fig.3-10).
1 3 Robert L. Thayer, Jr., Solar Access - It’s The Law, 1981, p.4, University of California, Davis
\ /
summer
morning
Z''- _ / \
i \ ' v
< ' V . .
^ y ^
/ \
/ \ fZ v. rv ^
' < y < N ’ < S ’
summer winter winter composite
afternoon morning afternoon plane
Fig. 3-10: Composite plane for solar envelope
31
3.5 Definition of composite solar envelope with boundary condition
I
When solar envelope is set flat on the existing environment, the composite
solar envelope is very low volume, which optimally keeps all shading within the
bounds of the lot in question during the relevant hours. While such access may be
possible or desirable in a new development, it is wholly unrealistic if applied to an
existing developed area. Even in new developments, such solar access would j
generally be unnecessary unless ground level collectors are located right on lot |
j
lines. In most developed areas, the envelopes may be much larger than in new
»
j
areas because more shading beyond lot boundaries already occurs than under ideal
solar access conditions.1 4 I
Considering the varying situations for the surroundings can make the solar j
envelope a more practical zoning tool. It is quite possible, in a real context, that j
the neighboring sites contain land uses with different requirements for solar access, j
I
Boundary conditions can also be used to respond the neighbors, for example if j
j
there is a party wall right on the boundary line and it’s not necessary to protect the j
wall itself so the solar envelope can rise up to the high of that party wall. If the j
i
surrounding lot is parking structure or unused ditch and etc. there is no reason to ;
i
protect them from the sun light. Depending the use of surroundings solar j
i
envelope’s height can be adjusted (Fig. 3-11). i
1 4 Gail Boyer Hayes, Solar Access Law - Protecting Access to Sunlight for Solar Energy System, j
1979, p.48, Environmental Law Institute, Washington, DC
3 2
_ _ _ _ _ _ _ _ _ _ i
no boundary height
boundary height
= party wall
= lO’-O"
boundary height
= parking structure height
= 40’-0”
Fig. 3-11: Boundary conditions
33
4. SIMULATION METHODOLOGIES OF THE COMPUTER PROGRAM
The designated site is divided into appropriate grids along two axes. Thus,
the intersection points are calculated with given variables to give heights. A
number of heights on the same point are then compared to pick the smallest one.
Those picked height of each point is meshed to generate the solar envelope. i
The following conditions can be executed:
(1) Solar access calculation,
(2) Solar envelope for specified cut-off time without boundary condition
calculation,
(3) Composite solar envelope without boundary condition calculation,
(4) Composite solar envelope with boundary condition calculation.
34
F i g . 4 - 1 : Flow chart of the program
USER
OPTIONAL
INPUT
|
CALCULATED
ALTITUDE &
AZIMUTH
User input
latitude
list of cities'
latitude
Calculation
Output table / Altitude & azimuth
CALCULATED
SOLAR ENVELOPE
U/O SURROUNDING
ENVIRONMENT
User input
latitude
list of cities'
latitude
Solar access calculation
(Altitude & Azimuth)
Solar envelope calculation
W/0 surrounding environment
Graphic output
CALCULATED
SOLAR ENVELOPE
W/ SURROUNDING
ENVIRONMENT
User input
latitude
list of cities'
latitude
Solar access calculation
(Altitude & Azimuth)
Environment data input
Solar envelope calculation
U/ surrounding environment
Graphic output
Quit
Solar access calculation
The user must first enter the latitude of the site to be analyzed, the month
l
day, and the time. We assume that the earth has stopped at that particular time
then calculate the sun’s altitude and bearing angle. This is the start of the
calculations for the solar envelope.
4.1.1 Latitude
latitude = latitude of the site
This is the number input by the user.
4.1.2 Julian day
{julianday from January to December}
case month of
1:
begin
CalcJulianDay := date;
begin
CalcJulianDay := 31+ date;
end;
3:
j begin
CalcJulianDay := 59 + date;
end;
I 4:
begin
CalcJulianDay := 90 +date;
end;
5:
begin
CalcJulianDay := 120 + date;
end;
6:
begin
CalcJulianDay := 151 + date;
end;
7:
begin
CalcJulianDay := 181 + date;
end;
8:
begin
CalcJulianDay := 212 4- date;
end;
9:
begin
CalcJulianDay : = 243 + date;
end;
1°:
begin
CalcJulianDay := 273 + date;
end;
11 :
begin
CalcJulianDay := 304 + date;
end;
12:
| begin
| CalcJulianDay := 335 + date;
i end;
end; {of case .}
4.1.3 Declination
{declination = CalcDeclination}
CalcDeclination : = 23.45 * sin(toradians((julianday + 284) * 360 /
365))
convert from degree to radians:
toradians := degree * pi / 180
convert from radians to degree:
37
todegree := radian * 180 / pi
J 4.1.4 Hour angle
I {hour angle = CalcHourAngle}
CalcHourAngle := 15.0 *(12 - hour)
4.1.5 Solar altitude
(sin(altitude) = sinAltitude, latitude in radians = latitudeR, hour angle
in radians = hourangleR}
sinAltitude : = sin(latitudeR)*sin(toradians(declination))
+ (cos(latitudeR) *cos(toradian s(decli nati on))
*cos(hourangleR));
{altitude = arc( sin(altitude) ) = ArcsinAltitude}
ArcsinAltitude := arctan(sinAltitude/
sqrt( 1 -sinAltitude *sin Altitude));
I
i
i
K
| 4.1.6 Solar bearing angle
| {sin(azimuth) = sinAzimuth, hour angle in radians = hourangleR,
J altitude in radians = AltitudeR}
sinAzimuth : = sin(hourangleR)*cos(toradians(declination))
/ (cos( AltitudeR));
{bearing angle = azimuth = ArcsinAzimuth}
ArcsinAzimuth := arctan(sinAzimuth/
sqrt( 1 -sinAzimuth*sin Azimuth));
4.2 Solar envelope for specified cut-off time without boundary condition
calculation
Design a grid system for the site then calculate the height on each point.
Depending on the solar angle from the specified cut-off time, computer calculates
the height of each point. Pick a lowest height on each point for the solar envelope.
The lowest height presents the worst case within the cut-off time (Fig. 4-2).
This calculation is of the envelope’s hypothetical change of shape as it
adjusts to the passage of time. For example, an envelope for 9 am will have a
different size and shape from an envelope for 11 am. If a separate envelope is
plotted for each hour through an entire day, the result is a time-space structure
produced by means of a transformation from morning to afternoon. If the time and
space constraints are symmetrical, so will be the transformation.
be undary I i ne
o >
a >
I
ID
st_north
:S i te:
01
( d
0 1
I
+ J
01
st_south
©
Fig. 4-2: Site variables
39
.1 Height calculation
variables:
AltSa : altitude array for summer morning
Alt Sp : altitude array for summer afternoon
AzJSa : bearing angle array for summer morning
Az_Sp : bearing angle array for summer afternoon
n l : grid number of the site
r : loop for row on the grid system
c : loop for column on the grid system
h i : temporary lowest height
{loop for calc. dim. & calc, height }
for r := 1 to n l + 1 do
begin
for c := 1 to nl-f 1 do
begin
{I = loop for start time and finish time}
for I : = StartTime to FinishTime do
begin
AltSa := altitudeAry[I];
Alt_Sp := Alt_Sa;
if azimuthAry[I] = 0.0 then azimuthAry[I] := 0.00001;
temp := azimuthAry[I]-(stAngle3*pi/180);
if temp > pi then temp : = temp-(2*pi);
{check solar angle and calculate base on which boundary line does the
sun arrive)
section 1:
if (temp > = 0) and (temp < = pi/2) then
begin
Az Sa : = temp;
dim := (XsiteAry[r,c]-Xo)/sin(Az_Sa);
Boundary Height : = westboundary;
if dim * cos(Az Sa) > (YsiteAry[r,c]-Yo) then
begin
dim := (YsiteAry[r,c]-Yo)/cos(Az_Sa);
BoundaryHeight := north_boundary
end;
end
40
section 2:
else if (temp > pi/2) and (temp < pi) then j
begin i
Az Sa : = temp; I
dim := (XsiteAry[r,c]-Xo)/cos(Az_Sa-1.57); j
Boundary Height := west_boundary;
if dim * sin(Az_Sa-1.57) > (st_north+site_w+st_south)-YsiteAry[r,c] then
begin j
dim := ((st_north+site_w+st_south)-YsiteAry[r,c])/sin(Az_Sa-1.57); J
BoundaryHeight : = south_boundary
end; j
end |
[
section 3: |
else if (temp > -(pi/2)) and (temp < 0) then j
begin
Az_Sp := temp;
dim : =
abs(((site_l+ st_east+ st_west)-XsiteAry [r,c])/cos( 1.57-(Az_Sp)));
BoundaryHeight : = eastboundary; |
if dim * sin(1.57-(Az_Sp)) > (YsiteAry[r,c]-Yo) then j
begin i
dim := abs((YsiteAry[r,c]-Yo)/sin(1.57-(Az_Sp))); j
BoundaryHeight : = north_boundary j
end; j
end |
!
j
section 4: |
else |
begin J
Az Sp := temp; i
dim := abs(((st_west+site_l + st_east)-XsiteAry[r,c])/cos(Az_Sp-1.57)); j
BoundaryHeight : = south_boundary;
if dim * sin(Az_Sp-1.57) > (st_north+site_w+st_south)-YsiteAry[r,c] then
begin
dim : =
abs(((st_north+site_w+st_south)-YsiteAry[r,c])/sin(Az_Sp-1.57));
BoundaryHeight := east boundary j
Fig. 4-3: Solar envelope height calculation
{calculate the solar envelope height} (Fig. 4-3)
Height := abs((dim/cos(Alt_Sa))*sin(Alt_Sa))+BoundaryHeight;
{the lowest height for solar envelope = tempLowAry}
{compare tempLowAry}
if Condition = 1 then
begin
if I = StartTime then
tempLowAry[r,c] Height;
end;
if Height < tempLowAry[r,c] then
tempLowAry[r,e] := Height;
end; {of 1}
{see Fig.4-4 for height calculation at each hour}
1 pm
2 pm
S '
gjfa*A
\
^ (^111
* \ A''
A u
.A
\
\
. / A
10 am
\
x
>
x -"' ^
4 . \
\ M
in , \
1 8 1 % V -
^ x \
\ N
\
\
\
\ / \
s '
3 pm
11 am
noon
Fig. 4.4: Solar envelope height at each hour
43
4.3 Composite solar envelope without boundary condition calculation |
i
i
In this section, this computer program already set the summer cut-off time I
from 9 am to 3 pm, and winter cut-off time from 10 am to 2 pm. This is the most
reasonable cut-off time that we could use but again it really depends on the J
location and function of your building, and may even depend on the personal desire
and so on. But the purpose here is to study the solar envelope in different condition
so within this computer program I set the value for cut-off time so user can see the
comparison between different site, street, and the orientation (Fig. 4-5).
summer 8am-5pm summer 9am-3pm
winter 8am-5pm winter 10am-2pm
composite envelope composite envelope
Fig. 4-5: Composite envelope
4.4 Composite solar envelope with boundary condition calculation
variables:
Height : the lowest height after comparison
BoundaryHigh : height on the boundary line
east boundary : height on the east boundary line
west boundary : height on the west boundary line
north_boundary : height on the north boundary line
south_boundary : height on the south boundary line
{see Fig. 4-6 for boundary condition variables}
Height := Height + BoundaryHigh (Fig. 4-8)
nor th_bo unclary
sciut h_boundary
Fig. 4-6: Variables for boundary condition
46
\
\
\
V''
\
\
s '
\
< $ >
J
\
\
east
\
, s '
, V"' x
SP % \
j Yl V"
A \
S ^ '
\
west
x^aiip
P k \
x r a i l
x
? \J >v/
A \
. >
north
\
south
Fig. 4-7: Composite envelope ^/ith
boundary condition on each direction
4.5 Changing variables
4.5.1 Changing the latitude
Latitude is the location of the site on the earth, different latitude has
different sun’s relative angle. On the same time the sun’s position will be higher
when the latitude is lower. That is why you get a larger volume solar envelope at
35 degree north latitude than 55 degrees north latitude (Fig. 4-8).
N 15 latitude N 25 latitude
N 41 latitude N 52 latitude
Fig. 4-8: Solar envelope at different latitudes
4.5.2 Changing the site size
When changing the site’s length it doesn’t change the shape of the solar
envelope but extends the dimension running east-west. When changing the site’s
width will also extend the dimension running the north-south, and the shape always
stays the same (Fig. 4-9).
Fig. 4-9: Different site length and width
49
When the width of east side street increases we get more solar envelope
volume on the east-south comer. When the width of west side street increases we
get more solar envelope volume on the west-south comer. When the width of north
i
side street increases the solar envelope’s ridge gets higher. The volume increases !
as well. There aren’t any effects when we change the width of the south side j
J street. Orientation is the degree off from north. When the orientation changes the
! ■ •
| building shape will be different based on how many degree off from north then the j
I i
building envelope will be shift (Fig. 4-10, Fig. 4-11, Fig. 4-12). j
\
p ^ l l
P i k \
v-'
A \
>
A
/ \
15 Degree
v '-A -g
,>
30 degree
>
\
\
P a V"
a " " ^
a v
\
A
,>
60 degree
\
v A
A c
\ ^ I l k \
m
S i l k v -
A N
/ A
\ N
\ , A \
.A
A "
45 degree
\
Fig. 4-10: Different orientation solar envelope
V"-"
'A \
>
\
-A \
\
\
/ A
Fig. 4-11: Solar envelope at different
east and west street width
51
$
V''
Fig. 4-12: Solar envelope at different
north and south street width
52
4.5.4 Changing the cut-off times
The sun’s position is changes daily and hourly. In the summer time the sun [
is much higher than the winter time, in March and September the sun has about the j
same height. Solar envelope’s height is decided by the altitude and the shape by the
bearing angle (Fig. 4-13). For example, if the building north of the site is a
parking lot which doesn’t require sunlight, that side of the envelope will deform.
A s
\
7 am-5 pm
Fig. 4-13: Different cut-off time in the summer
4.5.5 Changing the boundary condition
Adjust the solar envelope high base on the request from the surrounding
site. Depending on the neighborhood’s desire, solar envelope need to raise up base
on the surrounding building function and the site needs. For example, if the
building north of the site is a parking lot which doesn’t require sun, that side of the
envelope deforms (Fig. 4-14).
Fig. 4-14: Different north boundary height envelope
54
5. APPLICATIONS
The solar envelope basically deals with time (the sun movement by day and
season) and space (the constraints of property), which are investigated in Chapter
j
j 3. When it comes to the application, other elements seem necessarily to be
!
i
| considered to make the solar envelope more practical and reasonable. Among the
elements to be considered are human activities and local climate.
Human activities actually follow the sun’s movement. In ancient society,
people started work at sunbreak and retired at sunset. The sun’s movement was
simply the indication of people’s living schedule. In today’s world, people’s
activities do not rely on the sun as much as before, but they usually show a
preference to stay under the sun, physically or psychologically. In an office
building a window seat is always desired by most people. People also tend to pay
higher rent for the office with more window areas. At lunch time, a bright plaza
usually attracts a larger crowd than a shady one. But in humid climate, as in
Taiwan, people are likely to stay under the shade of trees at a bright open space.
Local climate is an important element as well when searching for solar
envelope application. The solar access of winter is considered as the worst
condition and often the dominate case of a solar envelope. At a high latitude and
j cloudy climate, like Michigan or Oregon, where winter sunny days are not usually
available, taking the winter case to dominate the solar envelope may not be a
proper approach. The solar access of summer may be a more reasonable
consideration instead. But in Oregon, where summer months are normally in
raining seasons, the generation of a solar envelope is no more a simple task and
demands more study on the local climate.
SolVelope is a prototype program dedicated to generating a solar envelope.
It treats time and space as two variables as does the Solar Envelope Concept. What
a solar envelope guarantees is that solar access will be available during certain time
constraints. It is up to the designer to take advantage of the availability of sunlight
or ever to build shady, cool spaces. The solar envelope concept merely protects
this choice. The following applications show possible approach of this concept and
the tool.
r s .l Solar envelope zoning
i
J
!
) A solar envelope defines the volumetric container within which a building
j will not shade adjacent blocks. If the container is adhered to, every building can ;
i
protected each other. Solar envelope zoning represents an approach to solar access j
i
protection (Fig. 5-1). j
j
The solar envelope idea can be a zoning rule for cities, but the criteria for j
j application may vary with locations of cities. In the definition of solar envelope ;
I Prof.Knowles limits cut-off time and boundary heights to obtain more floor areas. !
i 1
j The cut-off time for city of Los Angeles had been set for summer at 9 am and 3
1
! pm and for winter at 10 am and 2 pm. When the adjacent building is for
I
I commercial use, the boundary height is raised by 20 ft.; when it is for residential
I :
use, the boundary height will be 10 ft. SolVelope gives a useful tool to verify if a
building is within its solar envelope and avoids shading the surroundings. Or a
i
i i
| solar envelope can be easily generated beforehand for designers’ guidance. ‘
t
Fig. 5-1: Solar envelope zoning
5.2 Plan Unit Development (PUD)
To break the strict limit and get more FAR under the solar envelope,
another idea, Plan Unit Development (PUD), is derived. PUD combines several
blocks to develop a single solar envelope (Fig. 5-2-1, Fig. 5-2-2). Each subblock is
developed under the integrated envelope to obtain more FAR and keep shadow
under control.
Practically, PUD somewhat responds to the needs of city growth. Besides
safe-guarding the quality of the environment, it greatly increases the acceptance by
developers of the solar envelope by allowing for higher densities.
Fig. 5-2-1: Solar envelope zoning
ro r iurn m e drawing'
th a progn is Enter key to
Fig. 5-2-2: Solar envelope under Plan Unit Development
5.3 Building grouping |
j
i
For urban planning or a large scale land development, building grouping
may be a practical approach. The initial idea of solar envelope is to protect the
i
adjacent blocks from the shadow of a proposed project. But if the protected block j
is a parking structure where adequate sunshine is not critical or desired, those strict
limitations become of nonsense. The concept of building grouping is derived from
this recognition.
I
Building grouping is an extension of the solar envelope and primarily j
|
applied to large scale land development. It does not specify the use of each block, j
1
t
Instead, several compositions are proposed for a given project and then |
investigated to obtain an optimal resolution. Criteria of evaluation lies on building j
function, desired cut-off time and boundary conditions,etc.. For instance, a parking
structure is required to serve an office building. A logical arrangement is to locate !
i
the office building to the south of the parking structure, because sunlight is less I
desired in the latter than in the former (Fig. 5-3).
Fig. 5-3: Solar envelope assuming a parking structure on the north block
A shopping mall is then added to the east block of the office building. To I
satisfy a cut-off time of 2 pm. to 5 pm. for the shopping mall, the corresponding
solar envelope of the office block would be as shown in Fig. 5-4. When the
shopping mall is relocated or a different use is designated to the east block with
another cut-off time, the solar envelope of the office building will change
!
accordingly. SolVelope gives an immediate response to the variation and allows for !
j
more possibilities, which makes building grouping a feasible approach. This j
approach makes the solar envelope more flexible and more applicable to an urban-
scale planning. Of course building grouping can be used with PUD to allow even
more flexibility in development.
|
5
Fig. 5-4: Solar envelope, assuming a shopping mall on the east block
61
5.4 Shadow control
Boundary conditions can be set in SolVelope to generate a solar envelope,
so shadow control can be easily achieved with this program. The existing San
Francisco Shadow Control Zoning is a good example of this application
(Fig. 5-5-1).
To protect the Unit Square from new shadow and give adequate sunlight,
the city of San Francisco established a regulation that no new buildings cast new
shadow on public spaces. As shown in Fig. 5-5-2, a new project is located at three
blocks from a public open space, like the Unit Square. It is obligated not to cast
new shadow on the designated open space during a particular time. A program
from University of Berkeley is currently applied by the city official to verify if a
proposed project is against the regulation by generating shadow to the
surroundings. If shadow was cast in the protected area, the proposed project will
be rejected and a modified proposal should be submitted for next review. This
procedure will be executed back and forth until the shadow is eliminated from the
protected area, which demands tremendous time and manpower for several cycles.
Therefore, construction schedule might be delayed due to this process. Doing
preliminary investigations in-house could save both the architect ad the city time
and expense.
62
| Fig. 5-5-1: Solar envelope restricting shadow on specific site
i
I !
| i
Fig. 5-5-2: Clarifred diagram showing street grid and solar envelope restricting
shadow on specific site
SolVelope reverses the preceding process by in advance generating a
| schematic volume with a boundary line set to the designated open space. The
schematic volume then serves as a guidance for the design team, — owners and
user’s representatives as well as design professionals, ~ to avoid casting new
shadow on the protected area. In addition, it saves tremendous money and
! manpower for the design team and the city officials.
6. FUTURE WORK
Program
The following suggests (Fig. 6-1-1, Fig. 6-1-2) some improvement to make
it more complete and powerful. It is hoped that SolVelope can spread the solar
envelope concept to all interested parties and lead to increased quality of
environment.
Allow a variety of sites in SolVelope. Only rectangular sites are supported
presently, which limits the feasibility of this program. Irregular, polygonal, and
sloped sites should be added to give users a wide selection.
Import data from industry CADD software. CADD programs have been
well developed and employed. Sharing data can speed input process and insure
accuracy.
Improve the interface to make the program more user-friendly. Graphic
interface is the main stream of computer operating environment today. It increases
user productivity and eases the operation to non-English users.
Provide on-screen help. Users can get help on any topic from anywhere in
the program. Instruction on how to execute SolVelope should be provided for first
time users.
Allow users to verify input data before executing the program. Users may
make mistakes during input without knowing it. A chance to review the data gives
opportunities to capture the errors and make corrections.
65
Associate input data with output. Keeping input and output on a single
hardcopy is a convenience for comparison and future study.
Support optional change on variables. Users may like to know the results
from one changed variable, such as cut-off time. In this case, users do not have to
key in unchanged data, saving time and avoiding mistakes.
Show numerical information with graphic output. Graphics help users
visualize the results. Numerical output gives a detailed information to advance the
use of SolVelope. Users can tell the tiny difference for research when the graphics
show no obvious discrepancy.
Create a built-in library for the building code. Cross checking a solar
envelope against the building code integrates two steps and helps design
professionals to detect zoning problems in preliminary design stage.
Accept graphic input. An irregular site and complicated surroundings are
beyond the capacity equipped with present SolVelope. Graphic input will greatly
increase its productivity.
Link to related programs, such as DOE2, SOLSHADE, and SHADOW.
Sharing data with these same-category software can integrate all the input and
output information. This feature broadens the utility of each single package.
Display multiple windows on one screen. Comparing results of variable
changes on the same screen, users can easily understand the interrelationship
among variables. This function also eliminates the need of hardcopies, when a
printer is not available.
66
! Allow users to tailor desired output formats. Formal reports usually follow
| a series of research. Tailored formats support a comprehensive presentation and a
!
j professional appearance. This flexibility also make SolVelope easy to upgrade to
I meet future needs and extension.
It is understood that more effort needs to be involved to achieve a
outstanding program. The preceding paragraphs list only a portion of desired
improvement and features on SolVelope. A questionnaire can collect more advice
from users in different fields. It is hoped that this prototype can inspire more
! people and draw more attention. Also, an advanced SolVelope can become reality
in near future.
FILE PRINT VIEW SCALE DATA EDIT TRANSFER CHECK HELP
P r e s s " T '* f a r T u r n t h e d r a M i n s u p 8 0 d e g r e e
P r e s s C n t e r h e w t o e x i t t h e p r g g r a e .
O
INPUT:
site
street
direction
boundary
file
OUTPUT:
coordinate
height
scale:100
unit: fee
Fig. 6-1-1: Future SolVelope user interface: case A
67
MENUi
FILE:
PRINT:
VIEW:
SCALE:
DATA:
EDIT:
TRANSFER:
CHECK:
HELP:
list file
open file
new file
save file
quit
set size
view document
text quality
graphic quality
printer option
select view point
select view direction
window
percentage
X scale
Y scale
output data
height/select point
solar angle/select date
color
draw
text
file edit
CAD
SUPERLIT
D0E2
city
FAR
height limit
solar limit
file
print
view
scale
data
edit
check
transfer
input
68
So IVeI ope;
File fcdxtS View Data Option Analysis Help
co I or
File Name
\
A
©
N
©
0
< s
A
draw:
text
f i l e
:Data
X-coor.
o . 000
2 . □□□
4 . 000
6 . 000 '
Y-coor
0 . 000
0 . OOO
0 . 000
0 . 000
m
Var iab
month =
date = 21
►
Fig. 6-1-2: Future SolVelope user interface: case B
MENU;
FILE:
EDIT:
new
open
save
save as
list file
print
quit
color
draw
text
file edit
VIEW:
DATA:
OPTION:
HELP :
view window
scale
rotate
input
output
transfer
library
index
template
70
Approach
Work with students in design studio to focus on FAR. Since the low FAR
has restricted the flexibility of the solar envelope to public, this issue need to be
faced and resolved.
Work with related parties in the local government. Local needs and
conditions may vary greatly. It appears the solar envelope protection can be best
handled at the local level. First-hand advice from the city council, the city planning
commission, and the department of city planning make research results more
accessible and into public sector sooner.
Work with developers, property owners, and design professionals to
investigate their concern if the solar envelope is applied on their undergoing
projects. These projects can be practiced in design studio of schools to explore the
flexibility of such application.
71
| 7. CONCLUSION
i
| 7.1 Objective of study
|
i!
i
1
J The solar envelope defines the largest volume of a proposed building to
|
] allow solar access to the adjacent properties. As a zoning tool, when applied
J evenly over a given area, it can really promise better quality of our environment.
Two arguments had been raised against this idea. First, it does not allow sufficient
floor areas to encourage new developments, especially in urban areas of high
j
j density. Second, it limits the design freedom to flexible architecture results. These
two arguments make developers, property owners, and design professionals
unlikely to utilize the solar envelope concept. Though this situation limits the
j acceptance of solar envelope to public, it suggests a clear direction of amendment.
i
j The generation of a solar envelope demands familiarity with latitude, hour
angle, solar altitude, solar bearing angle, etc.. The process of making a solar
I envelope by graphics and physical models is time-consuming and somewhat
confusing to most students and design professionals. This might cause a barrier to
the spread of the utilization of solar envelopes. The emergence of SolVelope is a
timely and appropriate response to the need with solar zoning also incorporating.
Plan unit development and building grouping, the needs of society, both the
people of the community who use the spaces and the developers, can be met.
I
{
1 7.2 Use of SolVelope
i
!
i
i
!
| SolVelope computerizes the generating process of a solar envelope. It can
f
serve as a research tool to investigate how the building shapes respond to the sun’s
|
!
j movement, a design tool to locate the building cluster and shape a building, and a
| zoning tool to allow sufficient solar access to our environment. It improves
I
I efficiency and provides accuracy, stimulating students’ study interest and
I
willingness. It gives immediate response to variable inputs and uses graphic output
for presentation, making communication direct and comprehensive. The ease of i
j j
j generating a solar envelope might also help spread the idea to public. J
One concern about using SolVelope is that students might tend to ignore the
I applied knowledge behind the scene. Lack of knowledge on solar access will make
j students unable to judge the output. Without complete understanding on the entire j
j process, they will not know how to approach a proper resolution when
i
j encountering problems. It is beneficial to students that SolVelope is introduced for
j
i
| checking after physical models are completed.
7.3 Summary
|
| A solar envelope receives its form from providing solar access. It is a result
of solar rhythms, daily and seasonally. Nature is seen again in the building forms.
Shady comers are eliminated in the urban context. Not only is a solar envelope a
! passive way to protect sun access to adjacent buildings, it is also a form generating
I
j
! element, a way of shaping he built environment. When properly used, it can save
i
i
j on the operating cost of buildings by reducing HVAC loads in cold climate and on
solar hot water system and lighting. Saving energy is an urgent matter while
environmentalism is a universally common issue today. But most importantly, by
guaranteeing solar access it provides choice to a designer and hopefully will
improve the quality of our lives in more responsive buildings.
APPENDIX A
1. SolVelope
75
Press enter key for the menu
USER OPTIONAL CALCULATION:
1.Output for Altitude & Azimuth.
2.Solar-Envelope @ single day w/o boundary condition.
3.Solar-Envelope @ summary w/o boundary condition.
4.Solar-Envelope @ summary w/ boundary condition.
5 . Q u i t .
Please enter your choice:
1
Do you went to change your choice (Y/N):
n
|LATITUDE INPUT :
1 Do you need list of cities latitude (Y/N) :
JPlease enter latitude (degree) =
34
jPlease enter month and date w/space key.
6 21
IDate= 6 21
)Latitude= 34degree
I The
! The
i _ -
Julianday=
Declination
172days
= 23.45degree
HOUR ALTITUDE BEARING HOUR ALTITUDE BEARING
1 -30.81 163.95 13 73.17 -55.10
2 -25.86 149.35 14 61.79 -76.00
3 -18.38 136.88 15 49.49 -87.10
4 -9.08 126.43 16 37.07 -95.28
5 1. 47 117.57 17 24.80 -102.54
6 12.86 109.78 18 12.86 -109.78
7 24. 80 102.54 19 1.47 -117.57
8 37.07 95 . 28 20 -9.08 -126.43
9 49. 49 87.10 21 -18.38 -136.88
10 61. 79 76.00 22 -25.86 -149.35
11 73.17 55.10 23 -30.81 -163.95
12 79.45 0 .00 24 212.55 -180.00
note : counter-clockwise from south is positive
clockwise from south is negative angle
angle
Press enter key for the menu
76
Press enter key for the menu
USER OPTIONAL CALCULATION:
jl.Output for Altitude & Azimuth.
j2.Solar-Envelope @ single day w/o boundary condition,
j3.Solar-Envelope @ summary w/o boundary condition.
4.Solar-Envelope @ summary w/ boundary condition,
j 5.Quit.
Please enter your choice:
i 2
jDo you want to change your choice (Y/N):
I n
I
LATITUDE INPUT :
Do you need list of cities latitude (Y/N) :
Please enter latitude (degree) =
34
Please enter month and date w/space key.
12 21
I
Date= 12 21
iLatitude= 34degree
The Julianday= 356days
The Declination= -23.44degree
HOUR ALTITUDE BEARING HOUR ALTITUDE BEARING
1 -73.17 -124.91 13 30.81 16.05
2 -61.78 -104.01 14 25.86 30.65
3 -49.49 -87.09 15 18. 38 43 .13
4 -37.07 -84.73 16 9.08 53.57
5 -24.79 -77.46 17 -1.47 62.43
6 -12.85 -70.23 18 -12.85 70.23
7 -1.47 -62.43 19 -24.79 77.46
8 9.08 -53.57 20 -37.07 84 . 73
9 18.38 -43.13 21 -49.49 87.09
10 25 .86 -30.65 22 -61.78 104.01
11 30.81 -16.05 23 -73.17 124.91
12 32 . 56 0.00 24 259.44 180.00
(note: counter-clockwise from south is negative angle
clockwise from south is positive angle
Please input start-time and finish-time for solar envelope
w/space key.
12 21
77
Press enter key for the menu
USER OPTIONAL CALCULATION:
1.Output for Altitude & Azimuth.
2.Solar-Envelope @ single day w/o boundary condition.
3.Solar-Envelope @ summary w/o boundary condition.
4.Solar-Envelope @ summary w/ boundary condition.
5.Qu i t.
Please enter your choice:
3
Do you want to change your choice (Y/N):
n
LATITUDE INPUT :
Do you need list of cities latitude (Y/N) :
Please enter latitude (degree) -
34
Please input length and width of the site: ft
site length = 150
site width = 200
5.Quit.
Please enter your choice:
3
Do you want to change your choice (Y/N):
n
LATITUDE INPUT :
jDo you need list of cities latitude (Y/N) :
|Please enter latitude (degree) =
34
jPlease input length and width of the site: ft
jsite length = 150
|site width = 200
!Please input street width for each side: ft
east side street width =80
west side street width =20
north side street width =0
south side street width =80
Please input street orientation :
note:clockwise from north is positive angle
counter-clockwise from north is negative angle
street orientation = 0
78
Press enter key for the menu
USER OPTIONAL CALCULATION:
1.Output for Altitude & Azimuth.
2.Solar-Envelope @ single day w/o boundary condition.
3.Solar-Envelope @ summary w/o boundary condition.
14.Solar-Envelope @ summary w/ boundary condition,
i 5.Qu i t.
I — — f ---------------------------------------------------------------------------------------------
SPlease enter your choice:
4
Do you want to change your choice (Y/N):
n
LATITUDE INPUT :
Do you need list of cities latitude (Y/N) :
Please enter latitude (degree) =
34
Please input allow shadow height on each boundary line
east boundary condition = 20
LATITUDE INPUT :
Do you need list of cities latitude (Y/N) :
Please enter latitude (degree) =
| 34
Please input allow shadow height on each boundary line
east boundary condition = 20
west boundary condition = 10
north boundary condition = 0
south boundary condition = 0
Please input length and width of the site: ft
|site length = 150
site width = 200
Please input street width for each side: ft
east side street width =80
west side street width =20
north side street width =0
south side street width =80
Please input street orientation :
note:clockwise from north is positive angle
counter-clockwiste from north is negative angle
street orientation = 0
jPress enter key for the menu
USER OPTIONAL CALCULATION:
j l . Output for Altitude & Azimuth.
12.Solar-Envelope @ single day w/o boundary condition.
! 3.Solar-Envelope @ summary w/o boundary condition,
j4.Solar-Envelope @ summary w/ boundary condition,
j5.Quit.
Please enter your choice:
5
jDo you want to change your choice (Y/N):
I n
|
[Do you really want to quit: Y/N
REFERENCES
| Ada Louise Huxtable, 1982
| THE TALL BUILDING ARTISTICALLY RECONSIDERED / THE
SEARCH FOR A SKYSCRAPER STYLE, Pantheon Books, New York.
AIA Resrarch Corporation, 1976
j SOLAR DWELLING DESIGN CONCEPTS, The AIA Research
| Corporation, Washington, DC.
Clare Cooper Marcus, Carolyn Francis, 1990
j PEOPLE PLACE, Van Nostrand Reinhold, New York.
|
j Cyril Carter, 1987
j PASSIVE SOLAR BUILDING DESIGN, Pergamon Press, Toronto.
i !
i
| Edward L. Harkness and Madan L. Mehta, 1978
SOLAR RADIATION CONTROL IN BUILDINGS, Applied science
j publishers LTD, London.
j
j Edward Mazria, 1979
i THE PASSIVE SOLAR ENERGY BOOK, Rodale Press, Emmaus, Pa.
j Gail Boyer Hayes, 1979
j SOLAR ACCESS LAW / PROTECTING ACCESS TO SUNLIGHT FOR
j SOLAR ENERGY SYSTEMS, Environmental Law Institute, Washington,
I DC.
s
|
j Glenn Goldmen and Michael S. Zdepski., 1991
I ACADIA ’91 / REALITY AND VIRTUAL REALITY, New Jersey
j Institute of Technology, University Heights, ACADIA, New Jersey.Lisa
!
I
j Heschong, 1979
| THERMAL DELIGHT IN ARCHITECTURE, The MIT, Cambridge,
| Massachusetts and London, England.
I !
j Jonathan Hammond, 1980
j PLANNING SOLAR NEIGHBORHOODS, The California Energy
I Commission, Sacramento.
81
Lynn S. Beedle, 1988
SECOND CENTURY OF THE SKYSCRAPER, Van Nostrand Reinhold
company Inc., New York.
Paul Spivak, 1979
LAND-USE BARRIERS AND INCENTIVES TO THE USE OF SOLAR
ENERGY, Solar energy Research Institute, Golden, Colorado.
j Petter Pollock, 1980
| SOLAR ENVELOPE ZONING TO THE CITY PLANNING PROCESS /
i LOS ANGELES CASE STUDY, Solar energy Research Institute, Golden,
j Colorado.
5
j
i Ralph L. Knowles, 1974
j ENERGY AND FORM / AN ECOLOGICAL APPROACH to URBAN
I GROWTH, The Massachusetts Institute of Technology, Massachusetts.
j
Ralph L. Knowles, 1967
THE SUN / HEAT & LIGHT, School of Architecture, University of
Southern California, Los Angeles.
Ralph L. Knowles, 1981
SUN RHYTHM FORM, The Massachusetts Institute of Technology,
j Massachusetts.
! Ralph L. Knowles and Richard D. Berry, 1980
1 SOLAR ENVELOPE CONCEPTS / MODERATE DENSITY BUILDING
j APPLICATIONS, School of Architecture, University of Southern
| California, Los Angeles.
t
t
| Richard B. Andrews, 1972
j URBAN LAND USE POLICY, The Free Press, New York.
■ Robert Bennett, 1978
| SUN ANGLES FOR DESIGN, Robert Bennett, Bala Cynwyd, PA.
Robert H. Nelson, 1977
ZONING AND PROPERTY RIGHTS, The Massachusetts Institute of
Technology, Massachusetts.
[ R.Robert Linowes, Don T. Allensworth, 1975
| THE STATES AND LAND-USE CONTROL, Praeger Publishers Inc.,
| New York.
j Robert L. Thayer, Jr., 1981
SOLAR ACCESS / IT ’S THE LOW, University of California, Davis.
S. J. Makielski, Jr., 1966
THE POLITICS OF ZONING, Columbia University, New York.
I
I Thomas A.P.van Leeuwen, 1986
THE SKYWARD TREND OF THOUGHT,MIT,
'
I Cambridge, Massachusetts.
83

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Asset Metadata

Creator Yeh, Uen-Fang Patricia (author)

Core Title Computer aided solar envelope design

Degree Master of Building Science

Degree Program Building Science

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

Tag alternative energy,engineering, architectural,OAI-PMH Harvest

Language English

Contributor Digitized by ProQuest (provenance)

Advisor Schiler, Marc (committee chair), [illegible] (committee member), Kensek, Karen (committee member)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c17-784256

Unique identifier UC11348956

Identifier EP41429.pdf (filename),usctheses-c17-784256 (legacy record id)

Legacy Identifier EP41429.pdf

Dmrecord 784256

Document Type Thesis

Rights Yeh, Uen-Fang Patricia

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 au...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA