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Shading mask: a computer-based teaching tool for sun shading devices

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Shading mask: a computer-based teaching tool for sun shading devices

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Content SHADING MASK A COMPUTER-BASED TEACHING TOOL FOR SUN SHADING DEVICES by Effendi Setiadarma A Thesis Presented to the FACULTY OF THE SCHOOL OF ARCHITECTURE UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fullfillment of the Requirements for the Degree MASTER OF BUILDING SCIENCE May 1995 Copyright 1995 Effendi Setiadarma UNIVERSITY O F SO U TH ERN CALIFORNIA THE •CHOCK. OF ARCHITECTURE UNIVERSITY FAAK lO S ANOELEE, CALIFORNIA N O a F O R I This thesis, written by X fWF.&'J.'S under the direction of h i s Thesis Committee, and approved by all its members, has been pre sented to and accepted by the Dean of The School o f Architecture, in partial fulfillment of the require ments for the degree of Date S T Dtan ■sr/i &/*!■% • THESIS COMMITTEE ACKNOWLEDGMENT Above all, I would like to thank God, my Creator and Savior, who has helped me since the beginning of my study at University of Southern California, and made me able to finish my thesis on time. Also, 1 would like to thank Prof. Marc Schiler, my academic advisor and thesis chair He has helped, encouraged, and supported me with his valuable knowledge, experiences, guidance, and patience from time to time. I would like to extend my thanks and appreciation to Prof. G.G Schierle, Prof Douglas Noble, and Prof Karen Kensek, my thesis committee They have guided, helped, supported me with their knowledge and experiences that made me able to finish my programming and report. The advice, help, and encouragement of my classmates, Tim Eilers, Sanjeev Tankha, Mansour Farazmound, Soner Keskinel, Shweta Japee, and Cecilia Ines Jo, and everybody who has prayed and support me, are deserving of special appreciation and thanks. My thanks and love reach and embrace my wife, Tini Mustikowati, my son, Yoel Nugraha, my daughter, Rebekah Felenia, who have prayed, have encouraged me through their letters and conversations, and have waited for me patiently until I finish my study May God bless you all abundantly. TABLE OF CONTENTS TITLE PA G E...................................................................................................................... i ACKNOWLEDGMENTS................................................................................................ ii TABLE OF CONTENTS................................................................................................. iii LIST OF FIGURES............................................................................................................ v LIST OF TA BLES............................................................................................................. vii ABSTRACT........................................................................................................................ viii INTRODUCTION.............................................................................................................. 1 CHAPTER I CLIMATE AND ARCHITECTURE 4 11. Climatic Approach o f Building Design................................................ 4 1.2. Conservation.......................................................................................... 10 CHAPTER 2 TYPES AND CHARACTERISTICS Of SHADING DEVICES 14 2 1 The need of solar control devices....................................................... 14 2.2 Types of solar control devices............................................................. 16 CHAPTER 3 COMPARISON OF RECTANGULAR AND HEMISPHERICAL SUN PATH DIAGRAMS 35 3.1 Mazria’s Rectangular Sun C hart........................................................... 35 3.2 Olgyay’s Hemispherical Sun C hart...................................................... 44 3 .3. Comparison............................................................................................. 50 CHAPTER 4 SHADING MASK PROGRAM 53 4 .1 . Sun C hart............................................................................................... 53 4.2. Shading M ask........................................................................................ 56 4.3. Examples................................................................................................ 61 CHAPTER 5 THE COMPUTER PROGRAMMING...................................................... 65 5.1 Programming Structure......................................................................... 65 5.2. Evaluation and Findings....................................................................... 110 iii CHAPTER 6 CONCLUSIONS AND RECOMMENDATIONS 114 6,1 Conclusions.............................................................................................. 114 6.2. Recommendations................................................................................. 115 REFERENCES................................................................................................................... 117 iv LIST OF FIGURES Figure:................................................................................................................................... page 1.1- Energy optimization through building design................................................ 12 1.2- Elements of energy design concept................................................................. 13 2 .1 - Pendapa of a museum in East Java, employs overhangs to shade its open space.................................................................................................................... 18 3.1- Plotting sun’s position at a certain time on a sun ch art.............................. 36 3.2 - Constructing several sun’s positions............................................................... 37 3.3 - Sun patterns on a chart for summer, fall/spring, and w inter..................... 38 3 4 - Equation of tim e......................................................................................... 38 3 5 - Map of United States standard tim e........................... 39 3 6 - Rectangular sun chart, 32 deg. North latitude 40 3 7 - Rectangular sun chart, 40 deg. North latitude............................................. 41 3 8 - Mazria’s concept of shading m asks................................................................. 42 3 9 - Shading calculator adjustment for a window faces 45 deg. west of due south.................................................................................................................... 43 3 ,10- The projections of sun’s movements on a horizontal plane....................... 44 3.11- Sun angle calculator (40 deg. North latitude sun chart) with a cursor of calculator........................................................................................................... 45 3.12- Sun chart for 32 deg. North latitude............................................................. 46 3.13- Sun chart for 44 deg. North latitude............................................................. 46 3.14- Shading mask patterns of different types of shading device 47 3 15 - The overheated periods, superimposed on 32 deg North latitude sun chart................................................................................................................... 48 3 16 - The protractor to construct shading m asks.................................................. 49 3.17- The overheated periods and shading m asks................................................. 50 4.1 - Sun chart for 32 deg. North latitude on June 21 ........................................... 55 4.2 - Sun chart:for 40 deg. South latitude (annual)................................................ 55 4.3 - Sun chart Equator on December 2 1 ............................................................... 56 4.4 - Ratio of window height - overhang depth (h/d ratio)................................... 59 4 5 - Ratio of window width - fins length (w/1 ratio )............................................. 59 4 .6 - Shading mask o f overhangs for 32 deg. North latitude sun chart on June 21 ........................................................................................................... 60 4.7 - Shading mask of vertical fins for 32 deg. North latitude sun chart on June 2 1 ........................................................................................................... 60 4.8 - Shading mask of eggcrates for 32 deg. North latitude sun chart on June 2 1 ........................................................................................................... 61 4.9 - Plan and section of a window of an office building at 34 deg. North latitude................................................................................................................ 62 4.10 - Overhang design on July 1 ............................................................................. 62 4.11 - Plan and section of a window of a residential building at 24 deg. South latitude.............................................................................................................. 63 V 4 12 - Shaded times for March 2 3 ............................................................................ 64 5.1- The programming structure............................................................................ 66 5.2 - The opening form ............................................................................................... 67 5.3 - The welcome form .............................................................................................. 68 5 4 - The user’s guide menu form ............................................................................ 68 5 5 - The main screen.................................................................................................. 70 5 6 - The novice options of overhang....................................................................... 72 5 .7 - The novice options of vertical fins.................................................................. 72 5 .8 - The advanced options of overhang.................................................................. 73 5 .9 - The advanced options o f vertical fins.............................................................. 73 5.10- The Help About form ...................................................................................... 76 5 11- The complete theory form s............................................................................ 78 5.12- The search form 95 5 13 - Example o f building design........................................... 96 5.14- Example of shading design.......................................... 101 5 .15 - Table of glazing form ....................................... 103 5.16- Table of shading coefficient form .................................................................. 103 5.17 - Table of effectiveness of shading devices form ........................................... 104 5 18 - Table of latitude form ..................................................................................... 104 5 .19- Table of sun p a th ............................................................................................. 105 5.20 - User’s guide form s.......................................................................................... 106 5 21 - An annual sun chart for 20 deg North latitude............................................ 112 vi LIST OF TABLES Table:.................................................................................................................................... page 1. Summary of architectural approaches related to the climatic considerations 9 2. Solar transmittance of awning materials............................................................... 21 3. The performance of some glazing........................................................................... 27 4. The shading coefficients for various shading devices.......................................... 29 5. Summary o f sun shading devices............................................................................ 30 vii ABSTRACT Sun shading affects natural lighting, ventilation, solar gain, and overall building performance. Few architecture students, architects, and designers have applied solar shading as a useful tool to reduce glare, control light intensity and radiation, and minimize the cooling load on their projects. SHADING MASK is a computer-based teaching tool that uses Edward Mazria’s rectangular sun path diagrams as a basis These charts are easier to understand than the hemispherical sun charts The tool explains the basic theory of solar control; generates sun path diagrams; allows the design of overhead, side, and eggcrate shading devices; calculates solar angles and shading masks; and provides case study examples o f actual buildings. Visual Basic 3 0 was chosen as the development language for this Windows- based program. SHADING MASK is a demonstration of how to integrate theory into a teaching / simulation tool to make important solar control information easily accessible to designers, student, and architects. INTRODUCTION Sun shading devices, either as parts of a building or separately placed from a building facade, are very interesting to study since they affect natural lighting and ventilation, solar gain, and overall building performance. The basic role of sun shading devices or solar radiation control systems is taught at almost every school of architecture. Also, there are some computer programs for shading devices that have been written either by students or software companies. Yet only few architecture students and architects or designers have applied the shading devices as a useful design tool to reduce glare, control light intensity, radiation, and minimize cooling load on their projects Some architects and designers even have a tendency to follow only owner requests or requirements while neglecting environmental aspects and energy considerations. This tendency may increase the cooling load of a building and may be followed by an augmentation of tremendous operating costs and energy use Eventually, owners or users o f the buildings themselves would pay these high costs. In fact, in many circumstances, applying a shading device to a building may reduce natural lighting within the interiors This problem may be resolved by better and more careful building design. Some building projects show that we can reach both energy saving and nice daylighting environments. The purpose of this study was primarily to develop a tool to help design or teach or re-teach solar radiation controls and their advantages in a clearer, and more interesting way. Having a readily available tool may also encourage architects and designers to use shading devices for energy reduction and lower operating cost in the buildings that they will design in the future. Will computers replace books in education? Originally, people learned through experience and interaction with other people. From this situation, people developed new l ways to leam. Lecture and group discussion with some written documents were developed in classical Greece. Teachers and students worked on a one-to-one basis. Teachers tended to give problems to their students to explore. This system does not work as well when the number o f students is targe. In order to solve this problem, printed materials were widely used. Today, learning by computers is widely used because the computer has many advantages. One major benefit of computers is that the computer can make learning an active process, while students still play a constant thinking role. Active learning is superior to passive learning in lectures (where only a few participate actively) (Bork, 1981:2) Alfred Bork wrote that it appeared likely that computers would soon be more important in our educational process than books, and indeed, might entirely replace book media for many purposes A thesis titled "A Computer-Aided Method for Shading Device Design and Analysis,” written by Richard James Rogers (1979) suggested that the development of computer simulations of energy usage in buildings has been spurred by the advent of the energy crisis but their use has been hampered by difficulties of numeric input The study was based on Olgyay's hemispherical sunpath patterns, and the author used interactive color graphic displays to make his program easier to operate and understand. The result was intended to be used more as a design tool rather than as a teaching tool Another computer program titled "Design Tools for Solar Rights and Sun-Shades Determination" is written by Edna Shaviv She stated that most Israeli public houses are designed with different external sun-shades but seldom is their geometry the best to prevent summer direct radiation and to allow winter insolation Her two generative CADD tools are: a method for the design o f fixed and moveable external sun-shades for any window located on a wall, and a method for the determination of the layout of solar communities so that each passive collector will be properly insulated. 2 Based on the fact that rectangular sun charts are easier to perceive and understand than the hemispherical sun charts, 1 decided to take Mazria’s rectangular sun path patterns as a a base of my computer program. In the following chapters, this study discusses climatic and energy conservation issues, history, types, and functions of sun shading devices, compares the hemispherical and rectangular sun path diagrams and shading masks, describes the computer program, and closes with evaluations, conclusions and recommendations Visual Basic 3 0 was chosen as the development language for this Windows-based program SHADING MASK uses Edward Mazria’s rectangular sun path diagrams as a basis. The program explains the basic theory of solar control; generates sun path diagrams; allows the design of overhead, side, and eggcrate shading devices; calculates solar angles and shading masks; and provides case studies of actual buildings My hypothesis is that using a well-designed computer program to teach, and re- teach when necessary, the use of sun shading devices is more understandable, clearer, and more interesting than reading a book of the same topic. The result of this study consists of two parts: a written part called "SHADING MASK, A Computer-based Teaching Tool For Sun Shading Devices,” and a computer program called "SHADING MASK ” 3 CHAPTER 1 CLIMATE AND ARCHITECTURE 1.1. Climatic Approach of Building Design One o f humanity’s basic needs is shelter. Shelter functions as a protector against climatic pressures such as wind, rain, sun, dust, and other sources of danger and discomfort from the environment In fact, shelter may also create a comfortable environment, where people can do their daily activities. People have been responding to those climatic pressures in many ways. Topographical factors are some reasons why people create their shelters differently. Ralph L. Knowles (1974) in his book titled “Energy and Form," stated that it is possible that man-made arrangements demonstrate differentiation as a manifestation of man adaptive behavior Under certain circumstances, earlier structure would be expected to behave as natural systems Other factors such as material availability, construction systems, technology, and costs may also influence the process o f creating a comfort building to live in. Any effort during this process corresponds to the climatic conditions or to the climatic pressures themselves. Climate includes temperature, humidity, wind, and rainfall These factors form regional climatic conditions (macro climate conditions), while topographical conditions, building settings, pollution, and other local conditions may establish micro climate conditions. Based on the macro climatic conditions, there are some architectural approaches used by researchers, architects, environmentalists, and other experts to 4 minimize climatic pressures or to gain human comfort. Knowles (1974) described a study of form as a building response, which is focused on the control of daily and seasonal insolation, which has been achieved by generating forms with relation to daily and seasonal sun movements. This study will discuss the issue by separating the world climate into four prototypical climatic areas or regions hot-dry, warm-humid, moderate, and, cool climate areas Each of them has specific characteristics of climate and different architectural approaches. I l l Hot-Drv Climates In these areas, the sun is the major problem because it is extremely hot and bright, and creates overheating. The maximum temperature may reach 130 deg F (54 deg C ) but the minimum temperature may be as low as 45 deg F (7 deg C ) The outdoor temperature during daytime is very high but during night, it will be much lower. The outdoor environment is often hot, dry, dusty, and barren These factors are to be mitigated in order to gain thermal comfort within buildings. (Szokolay, 1980) People respond to these problems by creating courtyard-type houses with a shaded verandah facing this courtyard. In order to avoid high wind and dust, buildings usually have small openings and are often courtyard oriented Major openings may be present in courtyard-facing walls. Thick walls as closures are very effective to respond to large diurnal temperature differences. They act as high thermal masses, which will absorb solar radiation in the 5 daytime significantly and effectively, as to allow much cooler interiors than exterior temperatures. Cooler fresh air may be taken from courtyard areas if natural ventilation is desired. The same walls will act as heaters during night time, when the outside temperature is lower and very cool. These walls will reradiate daytime solar radiation into the interiors, providing a warm and comfortable environment. Many buildings have water pools in their courtyard areas, serving to cool the environment through evaporation. Trees and other plants in the courtyard serve not only to increase the quality of the environment but also may function as sun shading devices since they will shade the courtyard. The advantages of compact building groupings and settlement layouts in these areas, (which are very common) rely on their ability to shade one another through closely spacing the buildings. In so doing, they will form shaded walkways, give protection for pedestrians against dusty high winds, and avoid useless outdoor open areas (Szokolay, 1980) 1.12 Warm-Humid Climates Szokolay ( 1980) stated that these areas of climate are the most difficult from the point of view of thermal design since, even though their outdoor maximum temperatures are lower than those of hot-dry climates, the diurnal temperature ranges are very low. The relatively moderate temperature, which is rarely exceeds 90 deg. F (32 deg. C ), but high humidity make these areas, in many cases, more unpleasant to live in, compared to hotter and drier climate areas. 6 People respond by designing shaded, verandah-type residential buildings with south or north primary orientations. Openness is the main characteristic of buildings in these areas So far, this approach is the best passive solution since large windows and other openings allow fresh air to come into building interiors. The use o f natural ventilation, admitting breezes all the time, is very common and important to make the buildings more comfortable to live in. Combining the suggestions of Kukreja (1978) and Szokolay (1980) on the main features of design and construction for dwelling in humid climates, the following brief discussion may help to form a clearer understanding. The roof is the part of a building which suffers most from solar heat gain and it also is the most important building element in blocking or minimizing solar radiation coming through the building. The use of reflective roof surfaces, separate ceilings, adequate roof ventilation, reflective surfaces for both the underside or the roof and the top of the ceiling, and reflective insulating materials for the ceiling can be very effective to gain a cooler space below the ceiling. Roof overhangs are very useful to shade walls and windows from sun, and protect them from damage caused by rain Openings on west and east walls should be avoided or minimized as much as possible, since these walls receive more solar gain than other walls Natural ventilation or breezes can be served by openings on north and south walls but again, these walls should be protected from direct sunlight in order to minimize solar gain, either by using roof overhangs, and other sun shading devices, including trees and plants. Separating buildings at certain distances will allow air movements between buildings as well. 7 To allow rapid cooling, especially during the night, lightweight building materials are recommended. Thus, walls are not used for thermal mass or thermal barriers, rather they function solely for protection against wind, insects, and also provide privacy. 2 13 Moderate Climates Rain, snow, cold winds, summer heat, and winter loads cause problems on buildings in these unique areas. For example, during winter, the requirements of these areas are very similar to those of cold climates, but the demand for compact building shape and insulation is not as great (Szokolay, 1980). These pressures have drawn people to create buildings with insulated large windows the facing winter sun (windows which face the equator will give best results), and large overhangs to block summer sun. Ventilation should be designed adequately, especially during overheated periods (during summer) but in winter, where the outdoor temperature may reach its lowest points, natural ventilation may be restrained. If sun shading devices are to be used for these areas, they should blockade high altitude summer sun but admit solar radiation during winter Besides, they may also perform as rain and snow protections The use of insulation on windows, floors, walls, and ceilings are very useful in moderate climates allowing minimum heat loss during winter 2.1.4. Cold Climates In contrast to hot-dry climates, these areas are often extremely cold Cold winds, low air temperatures, snow drifts and snow loads cause problems on shelters. 8 Szokolay (1980) confirmed that even the best buildings will need some active controls (some form o f heating). The major concern in cold climates is heat loss. Minimizing heat loss is the most important effort to sustain the thermal comfort environment indoors. Thus, insulation on walls, floors, and windows, and thermal masses are recommended. Basically, the heating period in these regions is very short. TABLE 1 SUMMARY OF ARCHITECTURAL APPROACHES RELATED TO THE CLIMATIC CONSIDERATION Hot-dry Insolation Sun, Dust Wind Dryness Utilize small amount of rain, level out large diurnal temperature variations Courtyard type, shaded verandah facing courtyard, often with pool or fountain, heavy walls with large time-lag Warm- humid Rain Heat Humidity Insolation Ventilation Cooling Shaded, verandah-type, length East-West, North and South walls; louvers for cross ventilation, high rooms, ventilated roof space. Moderate Rain Snow Cold winds Summer heat Winter load Minimum heat loss. Winter insulation. Summer shading and ventilation Good insulation, large windows facing winter sun, overhangs to exclude summer sun. Cold Wind Cold Snow Drift Snow Load Minimum Heat Loss Ideal shape: The Eskimo Igloo; minimum surface for larger volume few openings at right angles to wind direction 9 South facing windows (in the northern hemisphere) or north facing windows (in the southern hemisphere) will permit more sunlight to come into buildings Buildings must be protected from high wind, snow load, and snow drift. Tilting or dome-like roof shape will be effective to solve these problems. Table 1 above shows a summary of architectural approaches related to climatic consideration, derived from Szokolay (1980). 1,2. Conservation Lifestyle, modernism, and the individual preference for better environments have affected the quantity of energy needed The increase of urbanisation, including niodern buildings in big cities, and particularly high-rise and skyscrapers, has boosted energy usage to operate those buildings both electrically and mechanically Heating and cooling have the biggest part of total use o f energy within commercial buildings. Heating needs up to 40 % of total energy, and cooling needs around 20 % Lighting only needs 27 % and another 12 % is for miscellaneous uses (Shaw, 1989) Since the issues of energy availability and fuel prices have compelled people to make efforts for reducing energy usage in many sectors of life as well as in buildings, some experts and designers have developed specific strategies to reach the goal of reduction of energy use. Some strategies they have made include building design for energy optimization, passive system approaches, concepts of energy design, and others Fuller Moore (1993) said that conservation strategies for reducing energy usage are both defensive and offensive strategies during summer and winter seasons. The winter defensive strategies would involve strategies of how to minimize transmission and 10 infiltration heat losses, and how to reduce annual temperature sways. During summer, the defensive strategies would become how to minimize solar heat gain, conductive and infiltration heat gains, humidity, and daily and annual temperature sways. The winter offensive strategies would be how to increase winter solar heat gain (passive heating), while summer offensive strategies are how to increase natural ventilation, and how to increase evaporative cooling. To optimize energy usage through building design, individual buildings and building arrangements should be created based on determining the maximum-energy used but still in harmony with the function of the space (Crowther, 1994) Cluster-type housing arrangements and multi-use spaces are examples of attempting to minimize energy consumption. Cowther also suggested that energy conservation will be achieved from maximum utilization of spaces, high population density, and the sharing of heat in properly zoned buildings (Crowther, 1994:119). Fig. I I shows one example of energy optimization through building design. The energy design concept (Fig I 2) consists o f four major elements. The first element is a statement of initial single goal or goals This statement may be in the form of qualitative or quantitative goals. The goal is very substantial because it will become a path for an architect or a designer assigned to work on the project The second element is site analysis, which may include climatic conditions (especially to determine strategies for passive cooling or heating, natural lighting, and micro-climatic design), topographical characteristics, orientations, and other important aspects of the site itself As the third element of the energy design concept, schematic design should include at least a study of 11 masses and their orientations, and envelope designs. This part will give results in form of window to wall ratios (percentage), other necessary openings either for daylighting or ventilation, and strategies for natural lighting and ventilation. The last element is design development and detailing, which may consists of specific solar shading devices, glazing types, insulation, and Heating Ventilation Air Condition (HVAC) design and calculations (Watson, 1993). blocks out ^cold north win warm rooma (center) living space (60Uth) , i j i buffer space (north) mechanical rooms (north) ii> ■ • ' t , 'i n , : 1 ! * J S ( open the sun (south) gree rehouse | (south) Fig. 1.1 Energy optimization through building design (for northern hemisphere). 12 Some strategies described above relate primarily to a passive design approach However, for certain circumstances, such as in high-rise buildings or modem buildings, where natural ventilation or daylighting are limited, and manual vertical transportation systems are probably impossible, the use of electrical systems are unavoidable. In order to keep the building from wasting energy, building automation systems have important roles in controlling energy usage within these buildings, resulting in on and off switching of electrical systems such as elevators, escalators, artificial lighting, and HVAC systems M statementofGoaifa) Development: ^ b i i i | l i n g i : ; : H I lin iR n iM n I Analysis: « :Schematjc Design: & Fig 1-2 Elements o f energy design concept. n CHAPTER 2 TYPES AND FUNCTION OF SHADING DEVICES 2.1. The need for solar control devices Shading design is based on the overheated period, i.e. the period when sunlight is not wanted, when windows need to be fully shaded. Windows should be fully shaded when the outdoor temperature is higher or equal to the comfort limit temperature. However, for certain regions, particularly cold climate areas, where the sun is needed at all times, shading is not required. In warm humid and hot-dry climates the overheated period may occur all year. Shading is strongly recommended to gain passive cooling by reducing direct sunlight penetrating through windows. In moderate climates, full shading is required during mid summer, but in winter there may be no shading needed, while partial shading is recommended during spring and fall, admitting morning and late afternoon low angle sun (Szokolay, 1980). Early examination of the nature, the duration and intensity of the exposure of building and site to sunlight and the related design implications is a very important issue jn designing buildings. The following four steps should be considered. First, determine the duration of exposure to sunlight and the degree of shading, as well as the position o f the sunlit and shaded zones on the proposed site The second step is determining the extent to which the building's facades are exposed to sunlight and shade. The next step will be preventing excessive internal room temperature by assessing the maximum permissible energy transmittance through windows And the last step, if 14 necessary because excessive heat gain is present in the interior, consider the use of sun control measures. In order to decrease the effect of sunlight, related to step four above, items below must be considered * Building orientation and room layout * Reduction in the size and energy transmittance o f the windows * Increase in the heat storage capacity of the internal building elements * Sun control devices * Natural ventilation * Air conditioning (Finbow, 1981) In designing effective and efficient solar control devices, some considerations below should be taken into account: * How to design stable, light weight solar control devices * How to design optimum lengths and numbers of control devices * How to get a good exterior appearance without sacrificing the need of appropriate solar control devices * How to minimize glare from windows near those control devices * How to maximize solar heat entering the room in winter * How to provide natural ventilation ( if possible or needed) for the interior * How to minimize construction and maintenance work and costs * How to minimize noise caused by rain and wind on solar control devices * How to simplify operation tasks (either personal, central, manual, or automatic) * Other factors related to building functions, locations, climates, and so forth 2.2. Types of solar control devices Generally, solar control systems or devices can be divided into four different types: natural devices, external devices, internal devices, and glazing. Natural devices use building orientations, trees, and shrubs to prevent buildings from receiving direct sun penetration. External devices which are used outside of, or attached to, buildings include roof overhangs, louvers, fixed horizontal or vertical elements, and particular glazing materials Internal devices include curtains, Venetian blinds, film coatings, chemical sprays, and other interior elements which are used to eliminate glare or heat from the sun (Fry and Drew, 1982) The last device, which is the use of glazing as a shading device utilizes certain types of glazing to block or decrease solar radiation such as heat-absorbing glass, heat-reflecting glass, and film-coated glass. 2 2 1 Natural Shading Devices Solar radiation can be excessive in summer, causing discomfort, excessive heat and glare The presence of trees, however, would give shade and shadow, thus reducing glare and heat But for certain areas, some types of trees and plants are only effective during summer, since in winter and spring they are leaf-less The advantages of trees and plants, especially the deciduous ones, aredue to their low cost, ability to decrease glare, ability to cool the air, aesthetic values, and visual privacy. To achieve an efficient shading effect, trees should be placed strategically. They must be able to block the morning and afternoon low sun angle. Their disadvantages however, include slow growth, limited height, different shading patterns to age and time, and maintenance 16 Their limited height make them impossible to apply on mid-rise and high-rise buildings, although for low-rise buildings they can be useful. Furthermore, they may endanger building foundations by their strong growing roots if they are planted too close to those buildings. Creeping plants or vines on a trellis or hanging from a planter will also give a satisfying result, particularly for east and west orientations (Lechner, 1991). 2 2 2 External Shading Devices External devices consists of several types of solar control devices In many cases, neglecting their construction costs, these types of shading will give better results compared to natural and internal devices, although in some cases they also have some limitations and disadvantages External devices may be an integral part of a building such as roof overhangs, verandahs, and thick walls with embedded small windows, and they can be separately designed outside the building or just attached to the outer enclosures. 2 2 2 1. Horizontal Shading The most powerful of shading devices in most circumstances is horizontal shading. This device is simpler than vertical shading It is most easily adjusted to allow winter sun yet still block the summer sun angles Overhangs (single shading element) will give best results if they are placed on the south facade for northern latitudes, and north facade for southern latitudes. However, for east and west windows, horizontal overhangs must be combined with vertical fins to have better shading effects. (Lechner, 1991) 17 Other important issues in applying horizontal overhangs are window placement and orientation on the walls of a building. The position of the sun at any time may cause undesired excessive solar radiation, entering the building interior through windows. It is primarily critical for east and west-facing windows because of the low position of the sun, i e the low sun angle in the morning and afternoon will require a very long overhang or angled vertical fins to minimize the sun effect. Therefore, the best results in employing only overhangs, avoid east and west-facing windows as much as possible. For north and south facing windows, overhangs will give the best results. Fig. 2.1 Pendapa of a museum in East Java, Indonesia, employs overhangs to shade its open space (author's collection). 18 A careful design o f east and west walls with their designed windows is needed if there is no other alternative. Since these window walls will need considerable length of horizontal overhangs, vertical fins must be added to the horizontal overhangs, even though they may cause some restrictions of view. In using horizontal overhangs, however, we must identify that solid overhangs tend to trap warm air. If windows are opened, the heat will enter the interior. Wind and snow load also cause problems on solid overhangs Solid overhangs with screens parallel to the wall are often used to cut out lower rays of sun In residential buildings, overhangs may be an integral part o f the extension of the roof or walls The use of overhang as an extension part of the roof, especially in residential buildings and other single story and low-rise buildings can be found abundantly in tropical areas, where the sun would shine all year with relatively the same amount of solar radiation. With pitched roofs, it is not only easy to extend the roof to get an appropriate length o f overhang, but also to increase building height. This approach creates more air space between the roof and ceiling Heat transmission from the roof can be minimized by the use o f natural ventilation within this space Different overhang effects can be achieved by modifying solid overhangs into louvered or perforated ones with the same lengths in order to maintain their functions. Some kinds o f louver overhangs can be rotated according to the position of the sun Louvered overhangs further can be divided into the following types: * Louvered overhangs parallel to the wall', these types of overhangs permit air movement or air circulation near shaded walls or windows. 19 * Louvered overhangs perpendicular to the wall these types of overhangs will cut out sunrays from the sides, they function similar to vertical fins. * Horizontal louvers in a vertical plane or multiple horizontal louvers, these types o f overhangs are very effective in blocking low angle sun, but may restrict some views. * Rotating horizontal louvers: these devices are ideal for north and south windows and more effective than the fixed ones, but they may restrict winter sun if desired Conceptually, louvered overhangs are used in order to cut solid overhangs’ length especially for high latitudes (when the sun is low in the sky) and/or east and west orientations. Large overhangs are both impractical and hideous solutions for the reasons above Two or more overhang elements can be associated to achieve required shading Another type o f horizontal device is the vertical panel Vertical panels offer free air movement near walls or windows and they can block low angle sun nicely. Views will be restricted, and care must be taken avoid summer sun entering from above the overhang. Awnings, if they are used to replace solid overhangs, may be of low cost, light weight construction, but are less durable and less maintanance free. In many cases, they also tend to trap warm air unless they are perforated or have an air ventilation system near the windows or walls or at their joints. Light colored surfaces which are exposed to the sun may minimize the amount of sunlight absorbed and transferred to the window by convection and radiation Up to 65 percent of summer heat gain on south oriented 20 windows and up to 77 percent of summer heat gain on west oriented windows can be reduced by the use o f awnings (Watson, 1993). TABLE 2 SOLAR TRANSMITTANCE of AWNING MATERIALS Canvas i 0 Plastic 25 15 Aluminum (separated slats) I 0 20 (Watson, 1993:168) In other cases, transparent overhangs or mirror glass awnings or glass fiber overhangs may give results similar to those of solid ones They also reduce the solar gain but give minimum protection against glare. Canvas or fabric materials can be used for these kinds o f overhangs. While they are low cost and light-weight construction, they may not last long, and must be replaced periodically. Again, light color surfaces are recommended to reflect the sunlight Shutters depend upon how well they can absorb heat from direct sunlight, and may be effective in reducing solar gain through windows up to 80 per cent Light color shutters will reflect much of the sunlight rather than absorb it The disadvantage of external shutters is that they may restrict views. Watson (1993) has stated that up to a 35 percent reduction in air conditioning costs has been associated with the use of roll blinds or shades (Watson, 1993:166). Incident sunlight may be reflected by their light colors, keeping the interior cooler. 2 1 2.2.2.2. Vertical Shading In contrast to south and north facing windows or walls, east and west orientations can not be shaded totally with horizontal shading devices during summer. Lechner (1991) gave an example. He described that to shade a 4-ft window on August 21 at 6 p.m. at 36 deg North latitude fully, an 33-ft overhang is needed. This solution, of course, is impractical both structurally and aesthetically. To shade east and west facing windows, vertical fins are more suitable, either fixed ones or movable ones They can block sun penetration every day or only at desired times Vertical perpendicular fm s may restrict views strongly, but total side shading is easily achieved. Vertical angled or slanted fin s either toward north or south will also give a better solution to block sun penetration from sides, but again views are restricted to one direction Fins angled south have the benefit o f allowing winter sun to enter, and excluding summer sun. However, to block sun penetration from any angle, movable or adjustable vertical fm s maybe a better solution. For east and west facing windows, these devices can be applied so as to maintain views but they are expensive and complex to operate. To get effective shading while maintaining views for east and west orientation windows, movable vertical fins are suggested. But the best solution in avoiding problems or east and west orientations is, place as few as possible small windows on those walls, except if those orientations will give great or important views. 22 2,2 2.3. Eggcrate Shading Devices Eggcrates initially consist of horizontal shading devices (overhangs) and vertical shading devices (fins) which are united together to form more effective devices for certain situations and orientations. In other words, these shading devices are typically combinations o f horizontal and vertical devices. There are also unlimited modifications of these types which enrich facades o f buildings. We have seen that the shading effects of these shading devices at different scales is identical, but variations of view from inside and exterior aesthetic appearance are very great (Lechner, 1991) As mentioned earlier, eggcrates will function best if they are applied to east and west windows or walls (especially in hot climates), and for the additional orientations or southeast and southwest in very hot climates (Lechner, 1991) The horizontal elements also control glare from reflected solar rays. But since they combine overhangs and fins together at the same time, the disadvantages o f overhangs and fins also become their characteristics, such as, restricting views and trapping hot air, especially for regular eggcrates. Some variations of these devices include eggcrate with slanted fms, and eggcrate with horizontal louvers Fixed eggcrates may be used for east and west facing windows although they also may restrict views These devices block sun penetration both horizontally and vertically, and may block it totally The vertical elements of an eggcrate may be angled as well. Angled or slanted eggcrates work similarly to vertical fins on restricting views on one direction and create asymetrical shading masks. Basically, adjustable or movable 23 eggcrates offer flexibility on shading patterns but they may be complicated and costly. They block sun penetration nicely as during desired times by adjusting their angles. 2.2.3. Internal Shading Devices Internal shading devices are usually attached close to windows and they often cover them totally. Some kinds of internal shading devices include curtains, shutters, roller shades, Venetian blinds, slatted blinds, a roller blind, or lightshelves. Compared to external shading devices, internal shading devices are less effective. They do not block, unfortunately, the sun while admitting views since if they are used to block the sunlight, they also block some views. In fact, these devices do block solar radiation behind window glazing, and the result is, obviously, much of the heat remains indoors (Lechner, 1992). The advantages o f interior shading devices rely on their capabilities to provide privacy, control glare, insulation, interior aesthetics, and they are less expensive than fixed overhangs, and easy to maintain, replace, and operate. During winter, where the sun angle would be low, and sunshine would penetrate deeply into rooms, the use of internal shading devices can be very useful in reducing glare. Venetian blinds or lightshelves will give a nice distribution of daylighting while controlling glare Another option of the use of Venetian blinds is to put them between window glazing (for double pane windows) Again, light colors (such as white) or mirrored finished blinds are recommended either for daylighting, cooling, and heating purpose Today, Venetian blinds are applied as external shading devices as well. 24 Lightshelves, depending on their dimensions, shapes or placements, may be included to external shading devices (if they are placed outside of windows), internal shading devices (if they are placed inside of windows), or combination of external and internal shading devices (if some parts of them are placed outside windows while the other parts remain inside o f windows) They provide excellent distribution o f sunlight while maintaining minimum glare and shading with uncluttered views Lam (1986) wrote that they are not only more durable and simpler to maintain but also more economical for a long period of time Compared to unshaded buildings with mirror glass or those with dynamic shading devices, lightselves should pay for themselves by savings in "purchased energy" for lighting and heating and reduced load for air conditioning They can add human scale and character to the interior of a building and visual interest to the facade 2.2 4 Glazing One method o f controlling sun radiation penetration is the use of different types of glass for different sun orientations (Andersen, 1984; Lechner, 1991) The incident solar radiation, however, will reach 100 percent of its value only if there is no glazing presence at all It means that it does not matter how thin and clear the glazing is, it still will absorb, transmit, and reradiate the incident solar radiation in such a way so that the radiation entering rooms will be less than 100 %. Basically, there are three kinds of glazing available; clear glass, heat-absorbing glass, and heat-reflective glass In using clear glazing, approximately 90 % o f the incident solar radiation will penetrate indoors. However, clear glazing is very useful for a passively 25 heated building, especially during the winter season, because it allows the sun to heat the interiors. Conversely, there will be much heat penetrating indoors during summer, which can cause discomfort, unless appropriate shading devices are used Clear glazing can not be used as a shading device. Heat-absorbing glass is one type of tinted glazing which can be applied to reduce light transmission but is limited in its ability to decrease heat gain. The solar radiation will be roughly 50 % absorbed, but then about 60 % o f it will be reradiated indoors. Thus the total indoor heat gain reaches 80 percent of the original incident solar radiation (10% less than clear glazing). This glazing has been developed with some nice colors (greens, grays, browns, and blues) which may add aesthetic values of facades of buildings. But it is not recommended to apply this glazing merely for controlling solar radiation, except during winter where the need of solar radiation may be critical. The last type of glazing available today is called heat-reflecting glass This glazing, which has a coating of metallic oxide or other materials, has been very powerful in blocking incident solar radiation, while maintaining views nicely. The reflectance of this glazing may reach 78 % of incident solar radiation, which is very significant in reducing heat gain through windows. Heat-Reflecting glass also creates images of other buildings, clouds, and surroundings, on its facades (mirror effect). The disadvantage of these glazings, however, are that they do not differentiate between light from the sun and light from the view, they filter out light all the time, and they also block winter sun, which is very needed during winter. Some kinds of this glass may distort colors o f the view, and darken views by their abilities on reducing light 26 transmission (Watson, 1993). Furthermore, these buildings sometimes reflect additional loads onto neighboring buildings, as well as glare onto sensitive areas, such as freeways or intersections. TABLE 3 THE PERFORMANCE OF SOME GLAZING Clear Glazing Single 1/8" 90 84 1/4" 89 78 3/8" 88 72 1/2" 86 67 Double 3/16" air space - 71 1/4" air space - - 1/2" air space 80 - Triple 1/4" air space - - Aciylic, single glazed 1/4" airspace 92 85 Heat-Absorbing Glass Double 1/4" 75 47 Clear insulating (double) 1" 80 y Heat-absorbing insulating (double) 1" 67 ? . Heat-Reflecting Glass Gray reflective single 1/4" 34 25 Clear insulating (double) 1" 80 59 Gray reflective insulating 1" 30 29 (Watson, 1993 171, 173, 174). Another opportunity to take advantage of heat-absorbing glass and heat-reflecting glass is to coordinate them in a comprehensive window design. Double-pane glazing using heat-reflecting glass on the outer side and heat-absorbing glass on the inner side of the window systems, with an air layer in between, will give a satisfying result. The use of 27 metallic oxide and other materials for coating sheets for reflective glazing surfaces has been very common since building appearances have been developed less expensively, and reducing air conditioning costs within the buildings because the film-coated glazing may reduce heat gain significantly However, Anderson (1984) suggested that if reducing heat gain is critical, heat- absorbing glass and heat-reflecting glass can help, especially on east and west facades He also gave some suggestions while using them as the following: * Such glass reduces solar heat gain (especially heat-reflecting glass) * They are almost unnecessary in north, north-northeast, and north-northwest facades, except in the latitude south of 30 degree North, and for glare control. * For south, southeast and southwest orientation, vegetation and operable shading devices are preferable to reflective glazing. 2.3. Shading Coefficient The Shading Coefficient (SC) is a number that varies from 0 to 1 . The value of each shading device is compared to the value of SC of a single sheet dear glass, 1/8 ” thick, which has an SC value equal to 1 . Thus, if a shading device has an SC value equal to 0, it means that solar radiation would be blocked totally Table 4 shows some values of SC of different kinds of solar shading device 28 TABLE 4 THE SHADING COEFFICIENTS for VARIOUS SHADING DEVICES IK*\iif M M ilinu < urlT u'im l Natural Shading Devices Trees 0.20-0 60 External Shading Devices Horizontal overhangs 0.10-0 60 Vertical fins 0.10-0.60 Eggcrate 0.10-0.30 Interior Shading Devices Venetian blinds 045-065 Roller shades 025-0 60 Curtains 040-0.80 Glazing Clear glass, 1/8” thick 1.00 Clear glass, 1/4" thick 095 Clear glass, 3/8” thick 0.90 Clear glass, 1/2” thick 0 86 Clear, double, 1/2”. air space 0.82 Clear, triple, 1/4”. air space 0.71 Acrylic, single glazed, 1/4”. air space 0 98 Acrylic, w/reflecting coating 0.21 Single Heat-absorbing, 1/4”. thick 0 71 Double Heat-absorbing, 1/4”. thick 0 69 Double Heat-absorbing insulating 082 Single gray reflective 0.60 Gray reflective insulating 0.47 Metallic oxides coating films as low as 0 24 R-18 film applied to 1/8" or 1/4” clear 0 26 R-18 film applied to 1/4” gray or bronze 0.30 (Lechner, 1991:170; Watson, 1993:171,173,174) 29 TABLE 5 SUMMARY OF SUN SHADING DEVICES 1. NATURAL I > pe of Device * Deciduous plants * Trees •Vines Hcsi Orientation East, West, Southeast, Southwest Low cost, views restricted, aesthetic values, slow growthjimited height, different shading patterns, seasonal 2. EXTERNAL: 2.1. Horizontal 2.1.1. Fixed Overhangs - Solid Overhang South, North, East, West Traps hot air, subject to wind and snow load - Louvered Overhang — Parallel to wall South, North, East, West Permits air movement, small load of snow and wind -- Perpendicular to wall East, West Cuts out sun rays from sides, similar to vertical fins -- Multiple horizontal louvers South, North, East, West More effectively blocks low angle sun, views restricted. 30 TABLE 5 SUMMARY OF SUN SHADING DEVICES (continued). T\ pt* of Device — Vertical Panel Best O rientation South, North C o m m e n t s Free air movement, restricts views, no snow drift — Rotating Horizontal Louvers South, North May restrict winter sun 2.1.2 Movable Overhangs - Awning South, North, East, West Low cost, light weight construction, less durable, maintanance free, tends to trap warm air -Transparent overhang South, North, East, West Minimum protection against glare, tow cost, light weight construction, replacable Absorbs heat, restricts views 2 13, Shutter South, North, East, West 31 TABLE 5. SUMMARY OF SUN SHADING DEVICES (continued). 2.2. Vertical Type of Bevice 2.2.1 . Fixed Fins - Vertical Fins Best Orientation East, West ('oiiiniciit* Ideal for hot climates, restricts views - Vertical slanted fms East, West A Slanted fins restrict views significantly (one direction) 2.3. Eggcrate 2.2.2 Rotating Fins East, West 2 3.1 Fixed Eggcrate East, West - Eggcrate with slanted fins East, West Much more effective than fixed fins and less restricted view than the slanted ones Ideal for very hot climates, tends to trap hot air, views restricted Slant toward North or South, for very hot climates n TABLE 5 SUMMARY OF SUN SHADING DEVICES (continued) I v |)f ul l)r\ ire itrvl Onriil.ilitin t oiiiiiiciih I 2.3.2. 1 Horizc t i ] i i j i Rotating >ntal Louvers East, West More effective with less view restriction than the fixed ones, ideal for hot climates 3. INTERNAL 3.1. Fiied j Lighshelf South, North, East, West Maybe external or internal devices, excellent distribution of sunlight, may be impractical for some latitudes 3.2. Movable j Curtain, shutter, ; roller shade, | Venetian blinds, ; slatted blinds, roller i blinds Less effective compared to external ones, may block both sunlight and views, less expensive, easy to maintain, ideal to reduce glare 4. GLAZING i - Clear Glazing Can not be used as a shading device, ideal for daylighting and solar heating (passive systems) | - Heat Absorbing • Glass i East, West Not recommended for controlling solar radiation, except during winter, but it may help to reduce heat gain if it is applied to East and West facades 33 TABLE 5 SUMMARY OF SUN SHADING DEVICES (continued). i'.vptf of Device I - Heat Reflecting i Glass - Heat Absorbing + Heat Reflecting Glass refl. ahs. East, West Blocks incident solar radiation nicely while maintaining views, causes glare to the surrounding, may distort colors of the view, ideal for glare control in very humid areas East, West Minimize solar heat gain better than other glasses, causes glare to the surrounding, distort colors of the view 34 CHAPTER 3 COMPARISON OF RECTANGULAR AND HEMISPHERICAL SUN PATH DIAGRAMS This chapter describes and compares two kinds of sun path diagram and shading mask: rectangular and hemispherical sun path diagrams. This part is intended to figure out the advantages and limitations of both methods. The results will be used as inputs for, and improve, the computer program based on the method chosen 3.1. Mazria’s Rectangular Sun Chart 3.1.1 Sun Chart The rectangular sun chart or cylindrical sun chart developed by Edward Mazria (1979) provides a simple way to learn and understand the sun’s movements for certain latitudes, which is conceptually between 28 deg. and 58 deg North latitudes. The chart comes in form of vertical patterns (elevations) of sun’s movements Mazria also stated that the sun chart was an earth-based view of the sun’s rotations or movements across the skydome Mazria’s concept of bearing angle and altitude angle is similar to that of Olgay’s The bearing angle (or azimuth) is a horizontal sun angle measured along the horizon of the sun position, from west or east of true south. The solar altitude is a vertical angle measured between the horizon and the position of the sun at a certain time. On the chart, however, the vertical lines of the grid represent a 15 degree increment o f bearing angles 35 while the horizontal lines of the same chart represent a 10 degree increment of solar altitudes. After drawing these tines, we must construct a skydome (sky vautt) which is defined as the visible hemisphere of the sky above the horizon, the grid on the chart then represents the horizontal and vertical angles o f this skydome (Fig. 3 1). This imaginative flat chart derived from the dome becomes a base to construct the sun chart at certain times, certain days, certain months, and even an annual chart of any latitudes Fig. 3 1 Plotting sun position at a certain time on a sun chart (Mazria, 1979) Once the solar azimuth and solar altitudes of a certain time are established, the sun position at this time can be found by looking the sun position through the skydome (or the chart) followed by plotting the position on the chart itself. By connecting the points of the sun position at different times throughout the day, the sun's path for that day can be constructed on the chart (Fig. 3.2) 36 Fig 3.2 Constructing several sun positions (Mazria, 1979) If we continue doing the same process for several times, a complete sun chart can be plotted (Fig. 3 .3 ) The times of the day (one hour increment) can be plotted by connecting the sun position at several different charts of the same latitude. However, these times are solar time. To convert a solar time into a standard time, Mazria gives the formula below: sun time = standard time + E + 4(L,, + Llo c ) where: E = equation of time from Fig. 3 .4) U = the standard time longitude line of the local time zone of the location Li« = the longitude o f the location (from Fig. 3 5) For example, for Los Angeles at 10.00 a.m. on October 30: the sun time will be: since Los Angeles's longitude is 118 degree, which is in the Pacific Standard Time Zone with a standard time longitude of 120 degree, the equation becomes: sun time = 10 00 + 18 + 4(120-118) sun time = 10.00 + 26 min. = 10.26 a.m. 37 s w E Fig 3.3 Sun patterns on a chart for summer, fall/spring, and winter(Mazria, 1 979) 1 a - w -H OCT. M M M F T OCC. MM. Fig. 3 .4 Equation of time (Mazria, 1979) 38 Fig. 3 5 Map of United States standard times (Mazria, i 979) Solar altitude at a certain time can be obtained by first determining the time to be measured and then drawing a horizontal line crossing this point The value can be read on the right side of the chart (altitude angles scale) By drawing a vertical line crossing the same point, the value of solar azimuth can be found at the bottom part of the chart Fig. 3 .6 and Fig 3 .7 are examples of rectangular sun chart according to Mazria’s concept. 39 v f WON atf — t m Z _ * c f t V AM -J - i' 1. J . - . •o r 4 6 ‘ a c r bearing angtee 90* 90 U East 0* u South Fig. 3 6 Rectangular sun chart for 32 deg. North latitude (Mazria, 1979) 40 a o * a d * 3 4 U 2 0 ' J.a 4 5 * 3tf bearing 3 t f « « * a t f 0*U South BO UEMt Fig. 3.7 Rectangular sun chart for 40 deg. North latitude (Mazria, 1979) 3 2 2 The Shading Mask. In contrast to Olgyay’s shading mask, which is drawn in the form of a plan, Mazria’s shading mask has three basic types of shading mask: curved lines for overhangs, vertical lines for fins, and curved-vertical lines for eggcrates. All o f them are drawn in elevations. Any obstruction outside windows of a building, either trees, buildings nearby, walls, and shading devices can be drawn to build a shading mask. To determine times where direct sunlight is blocked partially or totally, simply superimpose this mask over any 41 sun chart of any latitude and orientation because a shading mask is a geometric description of shading characteristic of the specific shading device (or other obstruction). But the mask itself is dependent on ratios of the device and windows dimensions, which eventually will generate a shading angle. Section a. Shading mask for overhangs 100 X Shading b M m 50 % Shading b. Shading mask for vertical fins. 100% /~y-SO% Mask c Shading mask for an eggcrates. Fig. 3.8 Mazria’s concept of shading masks (Mazria, 1979). 42 After this shading angle is determined, we can use a shading calculator (which is actually drawn by obtaining some shading angles o f different ratios) to plot the shading mask by superimposing the shading calculator over a sun chart. Curved lines of the shading calculator are used to draw horizontal obstruction lines parallel to a window (for overhangs) and the vertical lines are used to plot vertical obstruction lines parallel to the window (for vertical fins). Combining these lines, we can draw eggcrate shading masks easily (Fig 3 8) For a window with a certain orientation, simply move this shading calculator according to the orientation Fig 3 9 below shows the alignment of shading calculator for a window facing 45 degrees west or south. Fig. 3.9 Shading calculator adjustment for a window faces 45 degrees west o f due south (Mazria, 1979). 43 3.2. Olgyay’s Hemispherical Sun Chart 3-2.1. Sm C hart Victor Olgyay (1973) stated that sun path diagrams have more advantageous characteristics than other systems of projecting the imaginary sky vault with the sun paths on a plane Basically, the sun path diagrams show the sky vault which is projected on a plane parallel to the horizon plane. The horizon plane line itself then becomes a circle as we look at the plane from a height (Fig. 3.10) Fig 3 10 The projections of sun’s movements on a horizontal plane (Olgyay, 1957) The sun’s movements at different times can be constructed on the area within the circle in the form of curved lines. These lines, identified by days and months of the year, represent positions of the sun on the dates shown on the chart. We can see that some curved lines exceed the center point of the circle. This is possible since on the chart a small circle facing the observation point is flattened out into an ellipse like figure when it is near the edge, where one diameter remaining always the same and the other increasing until it reaches n!2 times as great (Olgyay & Olgyay, 1957). 44 C u r to r o f H*# C o k w * o » o r Fig. 3 11 Sun Angle Calculator (40 deg N lat. sun chart) with a cursor of the calculator (Olgyay, 1957) Fig. 3.9 shows a sun path diagram developed by Libbey-Owens-Ford for 40 degrees North latitude The company developed the “Sun Angle Calculator”, using sun charts together with a cursor with a scale of true altitude angle. In order to find solar azimuth and solar altitude for a certain sun chart we should have to overlay the cursor on the chart and adjust its pivots on times desired. The solar azimuth can be interpreted from the outer scale of the circle of the chart while the solar altitude can be read directly on the cursor The solar altitude on the chart is the angular distance above the horizon with a maximum value of 90 degrees. The solar azimuth is the angular distance which is 45 measured along the horizon in a clock wise direction either from south or north directions. Two examples o f sun chart can be seen on Fig. 3.12 and Fig. 3 .13 Fig 3.12 Sun Chart for 32 deg. North latitude (Olgyay, 1957) Fig. 3.13 Sun Chart for 44 deg. North latitude (Olgyay, 1957). 46 3 2 2 Shading Mask One of advantages of applying sun path diagrams is that overheated periods can be needed or where sunlight is needed. Thus, a completed diagram will provide both information of the sun’s movements and other information to evaluate shading devices clearly As we realize, geometrical forms or any outdoor obstruction have their own characteristics of shading masks dependent upon the latitude, the orientation, and the time Another factor that also influences the characteristic of shading is the scale or dimension of the devices themselves. Fig. 3 14 Shading mask patterns for different types of shading device (Watson, 1993). superimposed on the chart. By doing this, it is easy to determine times where shading is SEGMENTAL (OVERHANGS) R A D IA L (FINS) COM BM ATION (EOGRATES) 47 Olgyay* s shading mask has three types of shading: segmental lines for horizontal overhangs, radial lines for vertical louvers, and combination of them for eggcrate shading devices (Fig. 3 .14). He suggested some steps to construct a shading device as follows. The first step is determining times when shading is needed. Essentially, shading is needed during warm times (overheated periods, which is equal to 70 deg. Fahrenheit) in order to maintain an environmental comfort condition within the interior o f the building. The next step is determining the position of the sun path diagram, which shows the sky vault projected on the horizon plane. It is cited earlier that the overheated periods can be superimposed on a sun chart to ease the process of creating a shading device (Fig 3 .15) Fig. 3.15 The overheated periods superimposed on 32 deg. N. latitude sun chart (Olgyay, 1957). The third step will be the determining type and position of a shading device which will interfere between the sun and the point of observation during those overheated 48 periods The shading device may be plotted directly on the chart using a protractor (see Fig 3.16) overlaid on the chart. This protractor can be used to draw any kind of shading device either overhangs or fins. This step also provides a reading of times where the sun is blocked or intercepted. In his book, Olgyay only described two kinds of shading: 100 % shading and SO % shading. The first shading means that the window will be totally shaded while the second shows that only a half of the surface is in shade The last step is designing a shading device based on previous steps The proper device can be derived from step three, where shading angles may be found from the reading o f segmental and radial angles read from the shading masks Again, these angles determine ratio o f the device to a surface area (wall or window), dependent upon the device to be used Fig. 3 16 The protractor to construct shading masks (Olgyay, 1957) 49 Left: The overheated periods superimposed on a sun chart. Right: Shading masks drawn on a protractor, based on the times where shadings are needed. Fig. 3 .17 The overheated periods and shading masks on a sun chart (Olgyay, 1957) 3.3. Comparison. In his book titled "Passive Solar Energy Book,” Edward Mazria (1979) provided some sun charts based on latitudes from 28 deg. North to 56 deg North, However, he did not provide any sun chart from 0 deg. to 24 deg. latitudes to be studied or applied to a project. As we know, for latitudes lower than 23 5 deg. North or South, some sun paths will appear on the reverse direction of the chart plane. For example, for the Equator, only half of the sun paths can be plotted on south facing chart, since the other half must be constructed on the other side (facing north). However, overall, Mazria's rectangular method o f sun path diagram is easier to read and understand compared to the 50 hemispherical one. It does not need any special cursor to measure either a solar altitude or a solar azimuth of a certain time on the chart. Olgyay (1957) also provided some charts on his book titled “Solar Control & Shading Devices." Although he did not provide any sun path diagram for latitudes below 24 deg. North, it is clearly seen from his method that, for any latitude, the sun path diagrams would remain within the same plane of the circle. There is no need to provide another plane The imaginary horizontal line crossing the center point o f the circle acts as an equator line dividing the diagram into two sides, the northern side and the southern side For both methods, we may begin designing with either by establishing the ratio of the depth of the device to the surface to be shaded, followed by constructing a shading mask based on the ratio, and finished by testing the shading mask (by superimposing it on a sun chart). We actually can do this in reverse Determine the shading angle from the shading mask desired (which is constructed previously by drawing the shading mask based on the sun chart and shaded times desired) and then find out the ratio of the depth of the device to the surface to be shaded based on the shading angle. The shading mask can be constructed both for north facing windows and south facing windows with their variations o f orientation Comparing Mazria’s to Olgyay’s shading mask patterns, regardless o f the overheated periods which can be superimposed on a hemispherical sun chart, Mazria’s method is easier to construct and read, especially for shaded surfaces with certain orientations. It just needs a process o f aligning a shading calculator according to the 51 surfaces' orientations. The result of the shading mask can be read effortlessly. However, as constructing a sun chart for latitudes below 23.5 degrees will have a problem, the same problem occurs in the process of constructing a shading mask based on Mazria’s method Using Olgyay’s method, we can draw any shading mask on any sun chart independently. Both Olgyay's and Mazria’s books have limitations of constructing sun charts and shading masks. A computer program described in the following chapter, offers a simple way to plot a sun chart of any latitude and date along with unlimited variations of shading mask patterns, which can be overlaid on the chart instantly 52 CHAPTER 4 COMPUTER PROGRAM: SHADING MASK 4.1. Sun Chart Shading Mask computer program is written by author Since it is based on the rectangular sun chart method, the sun chart in this program comes in the form of an elevation plane. The main significant characteristic of the program reties on its flexibility to plot any kind of sun chart. Users can explore any sun chart from 90 deg. north to 90 deg. south latitudes (at one degree increment) and from January I to December 31 In fact, it may provide thousands of choices of latitudes and dates, and 180 choices of annual sun path diagrams to plot and study, and generates 65,700 tables of solar angles. The main screen has pull-down menus and command buttons as well, completed with two scroll bars o f latitudes and dates, so that users may explore any latitude and date desired The grid of bearing and attitude angles will remain on the main screen. An animated-like sun chart will show how the sun moves from east to west on the vertical plane (Fig. 4 1 and Fig. 4.2). Furthermore, users have two choices of plotting a sun path diagram on the main screen. They may explore a daily sun path diagram or an annual sun path diagram They do not need any other tools to measure the solar altitude and solar azimuth values since the program provides a table to print their values immediately The table is designed to plot solar azimuth and solar altitude values from 5 00 a m to 7 00 p.m. solar time for any latitude and date 53 Formulas used to construct a sun path diagram are: sin a = sin 8 x sin L + cos 8 x cos L x cos to cos L x sin 8 - cos 8 x sin L x cos to COS 0 = --------------------------------------------------------------------------- cos a where: a = solar altitude p = solar azimuth L = geographical latitude (the value is negative for southern hemisphere) to = hour angle (15 deg per hour from noon, am, negative) 8 = declination (from 0 deg to 23 5 deg.) The declination angle can be calculated as follows: 8 = 23.45 sin {360 x (284 + n)/365} where n = number of day in year, from January 1 . Following are some examples of sun path diagram evoked from the program (Fig. 4 1 to Fig. 4 3). 54 I lit' l i H A D I N i S M A ‘ »k f kr i i i | f n n i Ella S h a d in g M aalr E w am p laa E x p la in ... I a M e a H elp The Sun-path Diagram 2 * ♦ A I a i I M 4 S S S S ” SOUTH B««tirif A n g l i WEST Fig. 4.1 Sun chart for 32 deg. North latitude on June 21. U i r M I A h l N C i M A S K t ’nifjr/iii* E lla S h a d in g M atlc E x a m p le * E x p la in ... I a b l e a H elp T he Sun-path Diagram JuM 71 1 0 5 1 2 0 A SO UTH ■ ••linO Afit*• 3 Fig. 4.2 Sun chart for 40 deg. North latitude (annual). 55 U v r N H A l H N t i M A ' i f r l * f m ) 4 . i t i t p i» S ailin g M iit jy n n p li i Explria... I»bte« Help Latitude. Data A EAST ■ r£ ?x rv ! ''r,i Th« Sui Diagram u 90 40 » 1WW 75 C 0 ♦ SO U T H I t a i i n g Angle ♦ W E S T Fig 4.3 Sun chart for Equator on December 21. 4.2. Shading Mask Shading mask patterns in this program are also based on Mazria’s method of constructing a shading mask. To construct shading mask patterns, three formulas are applied The first formula, based on a ratio of window to depth of the device, is used to construct a shading mask for overhangs The second formula is used to draw a shading mask for fins, based on window-length o f the device. The third one, which is a combination of the previous formulas, is used to plot a shading mask for eggcrates. The formulas are: 0 = Atn (h/d), used for overhangs. y = Atn (w/1), used for vertical fins 56 where: 9 = sun angle on a window caused by overhangs (measured vertically) y = sun angle on a window caused by vertical fins (measured horizontally) h = total window height (including wall height between the window’s upper sill and the overhang) w = total window width (including wall width between the window’s side sills and the fins if any) d = depth of the overhang 1 = length of the fin The eggcrate shading mask patterns are obtained by combining these two formulas The shading mask for overhangs, then, can be plotted by constructing curved lines based on the G values (Fig. 4.4). The y values can be used to draw vertical lines to construct shading masks for fins (Fig. 4.5). Various h/d ratios and w/l ratios will give different types of a shading mask pattern By manipulating their ratios, we can easily plot 100 %, 50 %, and 0 % shading masks, or any kind of shading mask The user has unlimited possibilities of h/d and w/l ratios by simply typing their dimensions in the input boxes provided. To have different shading effects for overhangs, the h/d ratio formula becomes 100% shading: h/d ratio = (hl+h2)/d or h/d 50 % shading: h/d ratio = {hl+(5 x h2)}/d 0% shading: h/d ratio = (hl)/d. 57 Similarly, to have different shading effects for vertical fins, the w/l ratio formula becomes: 100% shading: w/l ratio = (w l+ w2)/l = w/l 50% shading: w/l ratio = {wl + (.5 x w2)}/l 0% shading: w/l ratio = (wl)/l. Note that 100% shading in this program is intended to the window surface only Users may investigate the effect of windows’ or walls’ orientations (using the same shading device) on times where the surfaces are shaded. Orientations o f a window can be changed at any time by changing the value of the window orientation scroll bar (either east orientation o f due south or west orientation of due south for southern latitudes, and vice versa) By so doing, users may explore 360 possibilities of window orientation The benefit is very clear. They can explore, compare, and analyze their projects freely, or they may have a better understanding on applying a shading device to a window or wall surface Fig. 4.6 to Fig. 4,8 show some examples of shading mask overlaid on sun path diagrams. 58 SECTION OF A W INDOW WITH AN OVERHANG 100% shading 50% shading % shading d - depth of the overhang hi - wall height above window H 2 ” window height h - total height a, b, c - shading angle Fig 4.4 Ratio of window height-overhang depth (h/d ratio) SECTION OF A W INDOW W ITH V ERTICA L FINS % shading U % shading 100% shading I - length of fin wl - wall width beside a window w2 “ window width w ” total width a, b, c « shading angle Fig. 4.5 Ratio of window width-fin length (w/I ratio). 59 I In :, M AI HN<> M A ! > K F S o i j m p i i Ell* jtwlin Mtit 6wmpl>i Expl*lp... I»blc» Help Tha Sun-path Diagram 1 0 •0 so BO 40 10 ID S 106 120 SO UTH W E S T EAST t i U i i I t i r i n g A n g l i p . i tm, i-mmmmmsm Fig 4.6 Shading mask of overhangs for 32 deg North latitude sun chart on June 21. N i r M I A l J I N l i W A ! i k I ' r i u i m m EH* S h id ln g M *»h E x t m p l n E x p la in -.. I * b l« * H elp Th« Sun-path Diagram H Lalituda: D a te : i r - •; ■ ! 7 SOUTH iJOTOSStTTS ♦ EAST ■ • • t i n g A n g I • « m. Fig. 4.7 Shading mask of vertical fins for 32 deg. North latitude sun chart on June 21. 60 Fig. 4 8 Shading Mask of eggcrates for 32 deg. North latitude sun chart on June 21 4.3. Examples 4.3 . 1 . Example U1 A small office building is located at 34 deg. North latitude. A south facing strip window requires shading totally during June and July, from 9 00 a m to 3 .00 p m An overhang is to be designed to shade this window (Fig. 4.9). Solution: Since in July sun angles are lower than that of June, we only need to design a shading device to protect the window during the days of July We may take July 3 1 as the worst case. We can plot the sun path diagram for July 31 by adjusting the latitude vertical scroll bar to 34 deg. North and the date horizontal scroll bar to July 31. By clicking the “Plot” button, the sun chart will be plotted on the main screen (Fig 4 10) The dimension of the window, and the height of wall above this window (if desired) must be put in the appropriate text boxes on Overhang form. We can try any dimension (depth) o f overhang and test the shading mask generated from the ratio against the sun chart, but a ratio o f h/d equal to I is recommended as the first try. By doing this step several times, the depth o f the overhang can be determined (see Fig 4.10). A 2 5 feet-depth overhang can be applied to the window. Latitude: 34 deg. North 40-00 t Office Bldg PLAN " overt1~ an9 * fo ? d S w 0f Fig. 4 .9 Plan and section o f window o f an office building at 34 deg. North Pit S l N I m I MA'.t I’n .ji mi f H tlp Tha Sun-patti Diagram Fig. 4.10 An overhang design on July 31. 62 4 3 2. Example #2 A residential building is built at 24 deg. South latitude. A T x 9 ‘ sqft. Large window is placed on the north wall. The building faces 30 deg. west o f due north. This window is completed by a series o f vertical fins placed 3’ apart. The length of each fin is 1 ’-6”. We are going to figure out times where the window is 100 %, 50 %, and 0 % shaded for March 23 (Fig. 4.11). Latitude: 24 deg. South 1-6 P - PLAN i l i i y q U — II Window 2-6* Sections Fig. 4 .11 Plan and window section of a residential building at 23 deg. South latitude. Solution: First, we must fill in the text boxes in “Vertical fins” with the dimension of the window and the length of the fin to generate a shading mask. This shading mask can be overlaid on the March 23 sun chart The times where the window is 100 %, 50 %, and 0 % shaded can be read directly on the screen (see Fig. 4.12). 63 H i r S I I A f U N i i M A S K Pi<njf,iM» p i e B in d in g M ««k E x a m p le * E x p la in .,. J i t l t i U «lp Tha Sun-path Diagram 130 105 1 L a M u d e : D a te A N O R T H B a i l i n g Angle Fig, 4.12 Shaded times on March 23 From Fig 4 12 above we can read that from 6 a m to 11 00 a m., the window will be shaded totally, from 11 00 a m to i 1 30 a m and from 3 45 p.m. to 6 00 p.m., the window will be 50% shaded, and 0% shading will happen from 11.30 a.m. to 3.45 p.m. 64 CHAPTER 5 PROGRAM STRUCTURE 5.1. Program Structure Visual Basic 3.0 was chosen as the development language for this Windows-based program. Fig. 5.1 shows the program structure. SHADING MASK consists o f two executable programs: Shading M ask and Theory. Both of them can be run independently This approach allows architecture students to study the Theory freely The Theory itself can be executed from the Shading Mask program (by clicking the “Theory” menu from the “Explain. ” pull-down menu of the main screen, which will be described later). The program may be run under Windows or directly from the DOS prompt (by typing C:\MASK\WIN MASK to run the Shading Mask, or C:\MASK\WIN THEORY to run the Theory, from the MASK directory followed by pressing the Enter key), If a user executes the program, a program title, with a short description explaining the program, will appear on the computer monitor. The form also provides some information about the writer, his address, and his chair and committee members. The user may go to the next screen by clicking a button (Fig. 5 2) The next screen is an opening screen (Fig. 5 3), which offers four options to the user. The default command button is the “Novice” button. This button is intended for beginners or for those who are not familiar with this program (or any Windows-based program). The “Advanced” button can be clicked directly if the user knows how to use 65 Execution PROGRAM TITLE Opening Menu Advanced Novice Explanation Sun path diagram Examples Tables Shading Mask Annually Shading Glazing SC Latitude How to (user’s guide) Advanced Building Novice Instant Sun path Shading Mask Exit ♦ Overhangs Fins Eggcrate Theory Angles -------- 1 — ..... Fig. 5 .1-1. The programming structure. SHADING MASK &jt*t*u S*tindftf»wa Fig. 5 .2 The opening form. this program The “Help” button will gives a guidance to a new user, on how to continue, and quit from the opening menu. The user may quit from this program by clicking the “Quit** command button. A user’s guide menu (Fig. 5.4) will be shown after a beginner clicking the default command button of the opening form. The user’s guide gives help how to start the program, how to plot a sun path diagram, how to plot a shading mask, how to explore examples, how to print, how to read the theory, and how to use help. The user can read the whole contents of this form or simply send them to a printer From the form “How to read the theory,” a user may go to the first page of the theory by clicking the “Read now 67 I l H i i M jD j'M liiM II IF iW t'fll Fig. 5.3 The welcome form. Fig. 5.4 The user’s guide form 68 ” command button. If he prefers to quit from the user guide menu, he may click the “Cancel” button. If he needs help to explore the help menu, he may simply click the “Help” button which will give him a short guidance on how to explore this help menu. But if he desires to continue, he may click the “Start” button. The main screen will then appear on the screen. The main screen (Fig. 5.5), which can be evoked directly from the opening menu by clicking the “Advanced” command button, has some features Pull-down menus are placed on the upper screen Moving a mouse pointer under each menu will show what the menu is for Moving a mouse pointer above command buttons will show what the button is functions. Those menus are: “File” menu to print and quit, “Shading Mask” menu to evoke the shading mask form and its options, “Examples” menu to explore some examples of building design, and shading designs, “Explain ...” menu to give an understanding about the sun path diagram, shading mask, and the theory, the “Tables” menu to provide tables needed to study or to design a shading device, and a table of solar latitude and solar azimuth, and the “Help” menu to give help on using the program There are a vertical scroll bar to choose a latitude desired, a horizontal scroll bar to choose a date to be explored, a “Plot” button to plot a daily sun path diagram based on the value of the vertical and horizontal scroll bars, an “Option” command button to plot an annual sun path diagram based on the latitude chosen, a “Shading Mask” button to plot a shading mask, and a “Clear” button to clear the screen. In the center of the screen there is a grid of solar azimuth (bearing angle) with 15 degrees increment and solar altitude with 69 10 degree increments. Any sun chart and shading mask will be plotted within the grid except for certain cases of latitude or date. Mir- M I A M I N M MA !.K M r t n j r , n n £! ! ■ gh^aim M««k p a w p le i Explilfl... M«lp i t l 'W l I Y * C O Th« Surv-path Diagram j i S O ts fs ♦ SOUTH 1 : .... 3 fl ■ 4s ‘ (id ' n ia 4* S O I I I I w 4 « ♦ WEST 50 -40 30 i20 iio ■ ■•ling A n g I • Fig. 5 5 The main screen The first pull-down menu is the “File” menu. This menu gives user guidance on how to print out a sun chart, shading mask options, a shading mask on a sun chart However, the “Print” menu can not print a sun chart and shading mask directly from the screen because I intend to show animated-like sun path diagrams and/or shading mask patterns on the screen. Users may print the sun chart and shading mask by pasting the graph to other Windows programs such as Write, Word for Windows etc. Clicking the Exit menu from this menu will end the operation. 70 The “Shading Mask” pull-down menu has three options: “Instant Shading Mask,” “Novice Option,” and “Advanced Option ” Each of them has three types of shading device option: “Overhangs,” “Vertical Fins," and “Eggcrates” The “Instant Shading Mask" option is intended to plot 100 % shading mask for h/d ratio = 1 and w/t ratio = 1 for a south or north facing window, dependent upon the latitude of the place. By plotting the instant overhang on any sun chart for example, one will know the shaded times immediately on the screen. He then may study this ratio and play with different ratios from other options of shading mask to see their shading effects The “Novice Option” is intended to be used by beginners (Fig 5 6 and Fig. 5 7) They can explore this option simply by clicking options of window height, wall height, and overhang depth which are available on the “Overhang form,” or window width, wall width, and fins length which are available on the “Vertical Fins” form On both forms, the ratio of h/d and w/l, and shading angles for 100 %, 50 %, and 0 % shading will change accordingly Users may explore the ratios and shading angles and see their effect on shading mask patterns. The “Advanced Option” (Fig 5.8 and Fig. 5.9) offers more sophisticated options of overhangs and vertical fins Instead of clicking values of shading components, he or she should type their dimensions in the text boxes provided on each form (the Overhang form and the Vertical Fins form). The ratio of h/d and w/1, and shading angles are also given on those forms. The users are encouraged to try any dimension they like to explore since they can see the results very quickly on the screen without any significant effort and time. This option may be used as a testing tool. If the users are doing projects and they are willing to 71 I lir Wnnlo w M t 1 1 1 1 1 1 t . i rh.nn| I I illii r ' i t ..... Fig. S .6 The novice options for overhang. W n i ( I i i v / W n l l h V > t f i < i l I m - H t l i 11 Widow / l i i bnglk toto S k d n i An*. m/t (U S iM ngl O X I k i A | w i h itiw HOI ahgdintf R W I M k »"*■ M WIRataa I100X rfw M H ngl 100k Shading ram | l w l k u t e n l a l i M l Fig. 5.7 The novice options for vertical fins. 72 Fig 5.8 The advanced options for overhang. I tlf W l l i l l l l W I j 111 V i ' l t l i ll I Ml . I t . 11111 n r r y p y i I,* P tTr.V.,.,.p . , . ,1 P T ^ L * "T* p V * - + p L ppp,pV pV .'fp* A f : : • : * ' l : : " » f c o S * * . < ■ : * : p s « - ■ , .* io t m/\ Pii* ( O K Fig 5.9 The advanced options for vertical fins test their designs, they may use this option and test the shading mask generated from their own ratios o f h/d or w/1 against a sun chart where the building locates. Then they can make some necessary changes to improve their designs In addition, both the “Novice" and “Advanced Options" feature with window orientation horizontal scroll bars. Users are able to explore the shading mask effects for windows which face north, south, east, and west with their choice of orientation (in 1 degree increments) This feature provides a wide range of possibilities which users can explore and study. They will learn how the shaded times will change as they change the orientation of a window (or a wall) The “Examples” menu enables users to study different types of shading device applied on eight existing buildings. They may learn how the buildings look like after employing certain types of shading devices. This part gives a deeper awareness of the effectiveness and aesthetic values of shading devices Fig 5 .13 shows one o f the available examples in this program Another option from this menu is that users may study shading design by opening “Shading Example” menu from this pull-down menu (Fig 5 14). Some clarifications about the screen (the grid, the sun path diagram, and the shading mask) and a theory o f shading devices may be examined from the “Explain...” pull-down menu. These explanations are very important since it is hoped that users may learned this program independently A clear and short description o f what is happening on the screen is designed to give understandings and knowledge of the topic and the program themselves as they may continue using this program to gain a deeper understanding. 74 By reading a theory of solar shading devices, it is also hoped that users will have additional knowledge and apply it on their projects. The goal behind this is simply to gain their awareness of environmental or climatic considerations, and create better living spaces in the future As discussed earlier, the Theory can be run independently or under the Shading Mask program. The theory itself may be read from page to page, or a user can go directly to the page he desires to read, or he can simply search topics to study by clicking any topic desired from the Search command button and clicking the topic itself The theory file covers of the theory on which the program is based, introduction to the topic, explanation of the chart, sun path diagram and shading mask, the need for shading devices, some reasons why shading is needed, types and characteristics of shading device, and references. The theory is not designed to replace books of solar control devices available but rather to simplify them as the users (architecture students) will face short descriptions of the shading devices on a computer monitor They themselves may study further by reading books suggested in this program, and improve their learning from courses they may take The complete theory can be read from Fig 5 1 1 The “Search” form (Fig. 5.12) is very useful to find a certain topic Users only need to choose and click any topic desired to explore. The “Tables" pull-down menu has four sub menus, that are: “Table o f glazing” characteristics (Fig. 5 15), “Table o f shading coefficient” of different shading devices (Fig 5 16), “Table of effectiveness of shading devices” (Fig. 5 17), “Table o f latitude” of cities (Fig 5 .18), and “Table of sun path” (Fig. 5 .19) Alphabetically arranged, the table of 75 latitude of cities provides a quick search of latitudes of cities to study. The latitude value then can be applied on the main screen to plot a sun chart. “Table of sun path” sub menu is needed to print the solar azimuth and solar altitude angles from a sun chart generated on the main screen which is based on the latitude chosen. Users only need to read this table instead of measuring the angles from the screen or a print out. They then may explore other sun charts and study their bearing and altitude angles By looking at these angles, designing a shading device to shade any window at certain times becomes easier The other three tables are important if users have no idea of what kind of glazing they are going to use, or simply by looking at the tables of shading coefficient they will know which device is the best for their projects, or they may choose one shading device and then improve it as needed. II, 4 r . U N , j M I ,1 I'" 'I..... I Fig 5.10 The Help About form. 76 The “Help" menu has two features. The first feature is intended to help users while using this program. As it is described earlier, this menu can be accessed either from the “Novice" command button of the opening screen or from the main screen help menu itself. The second menu (Fig. 5.10) explains the program shortly (similar to the program title screen) Fig. 5.20 shows the complete user’s guide forms. 77 SHADING MASK CONTENTS lntrt>dnrd»n d i i r t : Shading M a sk Sun Path D h |riM Sun Shading Devices 8«T«rtiir*i M i r ' i J i ' H l i m i M i .fc I *r i»i|i r]«i» luTrtiiltM I n u i e h « a«ip IN T R O D U C T IO N Sun (hading davicti, ttfher a* part* of a bidding or separately placed from a buddaig facades. art very nterertaig to me to study m e t they may affect natural lighting and ventatataon, and tolar gam, and overal buldatg performance Banc ally, the role of a n shaing devicet or aolar raduhon control vystems te taught at almoet every tchool of archdecture Aleo, there are lome computer progranu of shadmg devices have been written either by students or software compasses Yet, only few architecture students and architects or designers have applied them as a useful tool to reduce glare, control hght intensity, radiation, and rannaze cooling load on ther projects Some architects and designers even have a tendency to follow owner requests or reqivementt neglecting environmental aspects and energy considerations This tendency may nervate cooing load of bulAngs m d may be folowed by m augment aboo of tremendous operafang costa and energy use Eventualy, owners or ueera of the buddugs themselves would pay these high costa However, n ^ptymg a shading device to a braiding, in some cescumtances, the « * » » ^ i« « g device may reduce natural hgbtaig requred wehm the manors But this problem may be resolved by better ■nd more careful budAng design. And as a result, some buddeig projects show that, we can reach both energy saving and race dayfeghhng environments Fig. 5 1 1 The complete theory forms. 78 EHc Help primarily to m ilu k toot to help teach or re-teach dvantage* m • better, clearer, etd more atterettaig > 1 would eteo aococasge architect* end designer* to re due Boo and lower operatmg cort n the busldaigs >ugh e^ertence n d nteracBoo wtth other people pie found new ways to t e n sosnethmg Lecture and I document* were developed m cluneal Greece a one-to-one ben* Teacher* tended to give come tplored To accommodate a large number of people had a great dnadvant^e In order to tolve thu red widely a* a very useful tool ri n that compiler can make leanung an active conitanl tfankovg role Active Iranur^ is ruperror to nly a few of them participate actively (Boric, 1981, p appeared likely that computer! would soon be more is than books, and indeed, might entirely replace The purpose tolar rarhalMxi c < way Having a re uec the sharing < j that they will dea In the past, pi Developed from group ducueeion Teacher* and *tu problems to thee who intended to problem, printing One major b process, while it passive leanung i 2) Alfred Bork i important n our i book mednan foi IN T R O D U C T IO N The purpose of Da* program is primarily to make a tool to help teach or re-taach tolar rarkahoo control! and the* advantage* ei a better, dearer, and more interesting way Having a re eddy available tool would alto encowage architects and designers to uec the sharing devices for energy reduction end lower operating cost m the busldaige that they w tU dengn m the future In the past, people learned through e^iertenc* and interaction with other people Developed from thu situation, people found new way* to leant sosnethmg Lecture and group ducusnon with tome witting document* war* devetoptd in classical Greece. Teacher* and student* worked on a one-to-one basic Teacher* tended to give some problems to thee students to be esplored To accommodate a large number of people who intended to learn, this lyttcm had a great duadvant^e In order to solve this problem, prmbng materials were used widely as a very useful tool One major benefit of computers is that compiler can make leanung an active process, while students still play a constant thaikuig role Active leanur^ is superior to passive leanung ai lecture where only a few of them participate actively (Bork, 1981, p 2) Alfred Bork also wrote that it appeared kkely that computers would toon be more important m our educabooal process than books, and indeed, might entirely replace book mednan for many purpose* X S h j K j r t K I S S Fig. 5.11 The complete theory forms (continued) 79 I fir M i k I 'r m | i i m I n t r m l i h I n m E M * H elp IN T R O D U C T IO N Baied on « fact that many computer program of aolar control device! are bared on hemiphancal tun path pattern!, I decided to take M ania1 ! rectangular lun path pattern! ai a h u e of my computer program. On the foftowwg chapten. my ttudy ckicuiaer cknanc and energy coniervaoon a rues, tartory. typer, and (unction! of tun sbadmg device!, compare! the htmupbencal and rectangular tun path diagrams end thadeig maikt, describes the computer program, cloiei the study anth evahia&on. conchnaon* and recommaodattoa. Visual Banc 3.0 wae chosen at the development lac^uaga for tfaia Windows-based program SHADING MASK uaea Edward M u n a 'i rectangular run path dagramr as a b aw There chart! are carter to perceive and underrtand than the hesusphencd run chart! The program explain! banc theory of rolar control, generate! run path (fcagyami, aSowi the dcngp of overhead, nde, and eggcrate lhadeig devices, calculate! iolar anglei and lhadmg mark!, and provider care ituthei of actual building! My expectation u that uaaig a weS-de signed computer program to teach, and re-teach when necenary. the ure of tun ihadtng device! u more underitandable. clearer, and more aitereittng than reathng a book of the tame topic PI* M *lp Chart. The gtid represent! two dungs a) Horizontal kies represent altitude angle! of the tun from 0 to 90 degre*!. while b) Vertical knci re present azimuth ang|ei of the sun. from - 120 to 120 degree! Sove* M am a, fdawd. 'The Peak* Sal* t nwgi took. lOT Solar akKude u the angle measured between the honeoo and the posmon of the tun above the horuon. Thai! the gpd (chad) rapr«ient alMuda angler m )0 degrees aicremcots above the honcpn Aarttutfa or bearing angle u the angpe along the h tn tte of the poktian of theiun. which it meaeurad agher eatt or watt of true south Fig. 5.11 The complete theory forms (continued). 80 « pi <iui 111 E l l * U * l » Smtpath: A dady run path (or wncharQ that can baplqtted by putlang the "Plot* command button, ahowt a daily tun movement. The curve it obtained by connecting powu of tha location of the tun, * cliff«rcol hroai Ihrou^iout the day Black dott on the corye rtpretent tolar hour* at certain tana* throm^oullha day. from n o n a a to < afternoon, Tba letmid* of thaplacc and the date of the chart can be read nim all boxer belowthe chart. . Theaibtudc angge of a cattail aelar hour cm ha read by cbawvig a hamontal koe crotimg tha poant The Vafett of that angle Can be raadon the fight aide of chart Tha * U » p U * n n t l o t M t r t h a n LMudaa Souov Mma. f dwaid. "ThoPaaatva Sold E n a a B at." 1979 The aamuth of the point can b* obtained by drawing a vertical line cronaig the poelt The value of the beamg angle can be read on the tower part of the chart The complete value* of atatude and bearing angle■ can be teen by clicking Tablet and click Latitude! from tfcia pul-down menu. f * p i 1 1 1 1 1 I f it: S iiti \ '.ilti 9unp*ai(haaaato> dau M «ah Choote Tablet and ekek Table of Sun Path bom the pull-down menu to read all bearing and tfeidude anglet of the date and latitude chooian In dut 34 degree North tun path chart for example, the azimuth for December 21 at 3 pm it 42.7 degreet and the altitude tf l l 4 degree! Notice dtat for eertam datei of placet which have latitude» between 0 degree (Equator) and 23 3 degree (South or North), the tunpath dagram will go butaide the chart. The 24 deg latitude* (North or South) are tha mnraum latitude* for which yo« can plot a complete chart on the tame elevation. Fig. S. 11 The complete theory forms (continued). 81 1 * Jtl . i m I h i ' ■ ) i n V ’, lU h Eli* Help H tt green color shows Am an M wcb21 n 4 September 2 V A* Mo B o m from *MI tow est pespemhcitlat^ to 0 deg in * (a)tttid * w 9 Q dcytat) T he fed co*or shows 4 m th* fun move* on 4* ?thar dhrecbon (we would bev* to bee north to ece these chert*). 7Htanean*A**forttiote dates, the nm rotate* on the other hemasplure For example. (or 9 degree (equator) area*, half of flu mnpath patterns wifi be preeeM on southern pert of ifa< gM>e and the other half M ill be prater* on the northern part of the atebe. For tha cat* above, the southetn Mid northern pattern malar But for other areal (he southern pattarns wiD be ddfcreMcosnparedto the northern prtterns and vice vers* For latitudes higher than 67 3 the sunpalh psttems land to become straight horwontal lines, whech show that for b e s t laMudea tha net a i^ e i are vary low (they become horuontal h u i for 90 degree' laWtades) > It trl im j M .r t Elto Help • - :r Shading M ask: at Overtunifpr A thedng maik for an overhang m this program consists of three parte 0 sbadmg. 30 Vt shaskng. and 100 H shading The shadow angler can be obtained from aiktude atgfe tangent to die high**! pomt on the shading ciarvs The angles tan be read from 0 to 90 degree The windowwillbe totaRy shaded durvig Ae thnea A at A t sue is above the 100 H ahadiqglme. 30 H shaded a*the 50 V fc shading toe, end completely m sun M and below tha 0 K thadmg l*e The values of shadetg angles ant also nflueaced by the ratio ofthe depth of the overhang, the height ofthe tondow, and the beigl* of w al above this Window Tba higher h e ratio o f window^verhang (h/d), the higher the vertical an0e. Ah* the shorter the 1003i rfiachng hnt wifi be Shedeig m e* he ove*w gi Fig 5.11 The complete theory forms (continued) 82 Sha*x) M M k to vaecsl In In contra*; tohaee good ihatoig the oecthang can* be designed ccratMy to block tummer rat but ltd allow winter ran efectjvefc end to mnotnr dayii^itetg Thuc, the ideal would be 100 H shading oCeumi H Ct plots, and 0 K shoeing «f waster sun pedis b) Vertical Fin* A ihedatg iniaalc for it verticil fin in fee progrwfe consist* of three parti: 0 H dtodfcg, 50% shadaig, end IQOHshfchag Use lbadowang|Bs Can be Cfctafaed bymeCsurfcv edges of each box to the (/degree ofthe honeeotd astgle (seea figure below) thatoxi M« * to * « o e e I n Die angles can be reed from 0 to 90 degrees The window wd be totally •haded during the braes that the run i* outside the 100 % shading line, 56 % ■haded at the 50 % shading line, and completely unshaded below and at the 0 % shadeie lute r x -x -; The eggcrate shadng __te«ni mask b thss program u obtemed from h/d and wA E H ^ ^ M H H ratios for South or North : S H _ ^ H H E ^ H & c w g w m d o w * r | i EH H i \ Shadne Meakta E niieii Fig. 5 11 The complete theory forms (continued). 83 ■ I i . u l m t ] M . r . k l (t i n | i . ) 4i» M t l | i EH* b*lp T H E E F F E C T O F S U N S H A D IN G D E V IC E S O N R E D U C IN G C O O L IN G L O A D Tha need for Solar Control Device* Tha ihadng design u based oa the overheated period, l* the period when tunkgfx is not wanted, whan window* m ad to ba folly shaded Tha foty shaded wmdows should be provided when the oiXdoor temperature u higher or equal to Ibe comfort km* temperature (Sookolay. I960) However. for cart an regions, tspsoally which are included ■ cold climate areas, where the sun is needed at al tana*, rbadnig is not requrad In warm humid and hot-dry cknates the overheated period wi! probably all year. Shadng is shos^ty recommended to gam passnre cooing by reducing dxect simhght penetrating through window* In moderate denotes, foil shadaig is required durmg mid summer, but n waiter there may be no shadaig needed, while partial shading! is recommended during tpneg and fall, a (knitting morning and late afternoon low angfe run (Srokolay, 1980) Rasir Considerations. Early examination of the nature, duration, and mUnstfy of the exposure of buddmgs and tstes to sunlight and the related design impkeahoos are very anportam issues m designing bud<hngr Hie following steps should be considered Help I h r ! • h > r 111 h| M d ' i k I 'c 111 |i <m u 11 p l l i t liry > , > ..X v|fr£vt * Fart, detemxnatg the duration of exposure to sunlight and the degree of shading, as well as the position of the sunkt and shaded rones on the proposed sde The second step is. detenmning the extent to which the budding's facades are exposed to sunlight and shade. The next step is, preventing excessive internal room temperature by asieismg maximum energy trtnsnxttacc* through wxidows. Finally, if necessary, where excessive heat gain occurs in the Bitenor, consider the use of tun control measures. In order to reduce foe effect of sunlight, related to step four above, terms below mutt be considered * Buldxig orientation * Room layout * Reduction m the sue and energy transmittance of the window* * Increase in foe heat storage capacity of the xXeraal budding elements. * Sun control device* * Natural ventilation * Ax condmomng (Finbow, 1981) Fig. 5.11 The complete theory forms (continued). 84 E lla M « > p M u S f i h I i i h ) M u k I ' u H p r . n n M i l;i H u n r y ■ir: r: v: e r r : r - :" ." : In dcrtgring effective and efficient tolar tolar control devices. toane connderabons below ahould be taken mto account * How to dengp itable, kgh* weight aolar coobol devicet * How to detipi optaman length* and lumbers of control devices * How to get a good extenor appearance wdhoiX sacnficmg (be need for apprortatle aolar control devicet * How to minima# glare from window# Mar thote control devicet. * How to mammae tolar heal enterxig the room »i winter. * How to provide natural vastdanon (jf possible or needed) for the siienor * How to nanimue conjunction and mamtenance work and cortr * How to in w m u noise cauted by ram and a n d on tolar control devicet * How to sanptfy operation taakt (either penonal, central manual or automatic) * Other factori relate to bulckng fixicbons, locabout, and climates Type* uf Sular Control lHivict** Generaly, tolar control tyttemt can be divided into four ckfferent typet natural external, sitemal devices, and glaring Ella Help 1. Natural Shading D iv irtt Solar radiation can be very excessive at rummer, causing dhtcomfort. excessive beat and glare The existence of trees, however, would give shade and shadow, thus reducxvg glare and heat The advantages of beet and plants, especially deciduous plants, rely on thmr low cost, ability to reduce glare, and ability to cool the air, betides their aesthetic values and visual privacy Thex chsadvantages rnctude slow growth, limited height, different shading patterns to age and time, and mamtenance Creepxtg plants or vmet on a treQu or hangar from a planter wiD also give a sabafyng result, especially for east and wett enentabon* (Lechner, 1991) I. External Shading Devices Neglecting thex construction costs, external shadmg devices would give better results compared to natural and internal devices, although they also have some limrtabons and <hsadvantages External shading devicet may xictude roof overhangs, verandahs, thick wdU with embedded small wvtdows (an integral part of a biakkng). can be separately designed outside a buddxg) or just attached to the outer enclosures Fig. 5.11 The complete theory forms (continued). 85 Mir- !>Fi<n111hj M i' k M f d i j i . n n 11r 11■ E lla U « l> 1.1. H o ih an b l Sb»4ln| The moil powerful of ihadng dencei n mo it crcuratancei u boncotdal shading Thu kind of ihadmg u ampler than toy vortical ihtckig It is most tarty adjuetad to ■Sow w nttr run but block the sixmnar angles 3.1.1. The itM h u ti (single shading •liR eat). The overhang w i give belt rttult* f d M placed on the south facade for northern hamuphare. and north facade for southern heimtphere However, for hot and hot-humid area*, it also can be uaed for north and loidh windowi, depending on the latitude ofthe He. especially d r a g lufnmcr It ir alroort enpoiiible to ihade eait and wert facadei wdfa overhang*, eipeeially during rummer unlen they are combated with vertical (ini (Lechner. 1991) Other onportani dung n unng the bontontal overhang “ window placement and onrntabon on the wall* of a buddmg The run portion at any bme may caure undonred excessive rotar radiation, entering the btaldeig interior through windowi deecdy It u pnmanty cnncal for east and west-facsig windows becaure ofthe low portion of the run. thus the low altitude ofthe run m the rooming and afternoon will require a very long overhang or angled vertical fint to mmaniee the run effect Rgi SeUChwtwie Solid Overhangs In using an borwootal overhang, however, we mutt recognize that a lohd overhang tend* to trap warm an Wind and mow load alio cause problem* on lohd overhang* while infcd oveihangt w*h acreen parallel to wall are often uaed to cut out lower rayi of tun In a rendenhal buildutg, overhangi may be mtegral parti of it* roof or w all Wdh pile bed rooEi, it u not only easy to extend the roof to get an appropriate length of overhang, but alio to mcreaae buddmg height thui, d will provide more air apace between the roof and the ceiling 3.1.3. Delivered Overhangs Differed overhang effect* can be achieved by modrfymg solid overhangi ado louvared onet with the tame lenglhi in order to maintain thee fimcboni. Some lundi of lowered overhang* can be rotated acconfolg to the position ofthe sun (movable) ai desired, gaming an optnsum fincboo Lowered overhang* further can be divided into the folowmg types Fig. 5.11 The complete theory forms (continued). 86 H i r ', li.n111 n | M i ' l I ’i11<ji -i111 III 11< H ji o r v E i> « a«i> r F» 2 L o u v a n d 0 whang* Pad W d Fig 3 Lmndid 0 whang r * MpandoUstto Wst F® 4 HoKrontd L qltwi nA V eilK ^d * L ta v m d Overhang* Parallel to Wall: tha*a typ«i of overhang pdrmtf or movement or da trculmon near shaded i or wmdowt * L a u m d O n rk H n Perpendicular to Wall: theae devicet will cut out tutvayv from ■tda* They function ainiilar to vertical fin*. * Horizontal Loader* in a Vertical H i h or Multiple Horizontal LooTera; th e * e t y p e i a re e e r y e ff e c tiv e t o b l o c k lo w a n g le P in . b u t m a y r e n n e t n e w * I fir Mi.iitiitij I'fiitjf.Mit Hr Iji llit tiry 2,13, V n tic a lfa ftili fa & Verted Panel * Adjustable Hortiontai Louveri in A Vertical Plane these devicet are very ideal C or South and North, and more effective than Seed lowered but they alto restrict wetter tun if deteed They are alto expensive and complicated Vertical panels offer free an movement near wait or windowi They can block low angle tun nicely but they may restrict views at well Care mutt be taken avoid summer tun entering from above the overhang Fig. 5.11 The complete theory forms (continued). 87 ! ■ ll 1 ill! Hj M .1 ' k I '» I If ff -lilt I E H e H -lp 3.1 A. Awswigs Awnings, if they are used to replace solid overhang*, may gnu a low cost. hght weight construction but be less durable and nvantenance free, la many carer, however, they aUo tend to trap warm ar, unless they are perforated or have a vetfdahon ayrtam near the windowi or w ait or at their joints. Light color surfaces which m exportd to the run may i i the amount of swh^it absorbed and trans&red to the wbdow by convection and relation Up to 65 H of r r heat gam on south orwnted aaiodowi and up to 77 54 of i heat gain on avast oriented wmdoavs can br reduced by the use of awnmgs (Watson, 1993) 2.1.5. Trarvrparent overhang* In other cases, tranipareet overhang! or rntrror glass aavongs or glass fibre overhangs may gjve similar result! to those of solid ones Canvas or fabric materials can be used for these types While they are low cost and light weight construction, they may not last long, and thus they must be replaced penothcally 3.1.6. Shutters and Roller Btuuts/Shades F « 7 FWai flM 'S h ad t Shutters depend upon how well they can absorb heat from dire cl sunlight, maybe effective m reducing solar gam through wmdows up to 80 percent Light colors of shutters wil reflect much of the sunfrght rather than absorb it (Watson, 1993). They also may restrict views Watson (1993) wrote that roller bhnds/shades may reduce a r condftonmg costs up to 35 K Incident sunlight may be reflected by frsr light colors, keeping the intenor cooler ta Fig. 5.11 The complete theory forms (continued). 88 I h e ! i h . i d l M | M < t- L < 'i ixpr . t i n H t l | < I I n n i y Pi« U«» 3.2. Vertical Shading In contract to aoidh end north Eecng wmdows or walls, eact n d wect onentahons tan not be (haded totally anth horizontal shedxig device* Letbner (1991) Mated that. C or m n p b , to cbada a 4-ft w idow on A igwt 21 at 6 p m at 36 degree North laMude fuU y. an 33-ft overhang u needed The solution above u anprachcal, both ■ true Ur ally and esthetic aly To ahade east and west facing w ndotn, vertical fins are more statable, ether the fin d ones or the movable ones. They can Mock sun penetration every day or at deemed tans* To get an effective ehadng effect while marXammg new t for eact and west onantahoft window*, movable vertical fine are ci^gpsted But the beet cotuhon m avotdmg problems of east and west orientations, place at few at potable small wndovrs on those w ait, except if those onentataotu will give great or important views. * Vortical Perpendicular Fine These shathng devices may restrict new t strongly To mninaee tolar penetration effectively, the fins may be spaced closely, add them lerights or adjust their angles n F < 0 . 6 . V*rttS PependKti* Ftu 11 T h e ! . li t i In ti| M t ^ | 'i i»i|i .>i 11 11 r I |j 1 h r' ij i y Elle Help c Fig a V ertical AngM/Stanled Fna F ib 10 A dSjetahbA Sovehle V eskcg Fait * Vertical Angled/Slanted Fins Slanted or angled vertical fins, either toward north or south, anil also gjve a better solution to block cun penetration totally, but again, new t from the building interior are restricted to one direction Felt angled south have the benefit of allowing wwiter tun to eider, end excluding summer *. Adjustable/Movable Vertical H as Movable or adjustable vertical fin* may block sun penetration from any angle For east and west facctg wrndowt these devices can be employed to maintain views They are cosily and not easy to operate 1 2 Fig. 5 .11 The complete theory forms (continued). 89 I i n - '» 11 1 i ln t 11 M . i ’. I I i ' n \ r . i m I l r l | t I li r l i f v eh* tj*i* 3.3. £ ||tn tM Eggcrate i h i 4 t | device* rub ally cooiut of horuontal ahadmg d e n c n (ovoliiap) tad vertical ihading device* (fin*) which ire combined together fontang more eSectiv* devicei For certm iXuabon* and oneniabon* There « • alto tailnnted modificafcoa* of theie device* They wil function belt f they ire appkcd to c u t or we*t window* (etpecteUr » hot tkmatei), end for die addftonal orientation* or louthaait and louthwett n very hot ckmatei (La chner, 1991) Fig *1 Find Eggcrate * fixed E ||c r d a i Fixed eggcrate* may be uted for ea*t and we it facing window* although they alio may reitnct new* Theie dence* block iud peoevahoc both honxoetaOy and vertically, and may block X totally The vertical element! of an eggcrate may be angled a* well II E H * M el? I h r ‘jh-iriiiHj M i i : l I 'i u tjf a i h Mi J|> \ In m y 0 f i l Fig 12 An^ad/Slartad £ ggcMte 0 Fig 13 A d u M ta A to v a U * E g g o a t * Angl ad/Sl antad Eggcrate ■ Theie eggcrate* work malady with vertical fin* on reatncting mewi on one drecbon and create aiymetncal ihading maiki * A 4|iutabb/M ovaht* Bggcrata* Movable or adjurtable eggcrater offer flextbehtie* on ahwhng pattern*. But they may comphcMd and exp enure They block run penetration nicely a* during denred bmei by adjuring they angle ■ 14 Fig. 5.11 The complete theory forms (continued). 90 EWt t f r l p Mir U i n l m i | M . r . k Mr l|i 3. h t m i l Shading Device* Internal (hading device*. u they ar« caled. are placed at the manor UiuaOy they are Mtached dote to window* and diey often cover them totaiy Some kaidi of menial *hadmg davicai include curtame. dam an. roDar (hade*. Venetian bkndi, flatted bkida, a roOar bind, or a Ijgtttriwlf Compared to external (badetg device*, attemal dtading dencet are much leu effective They do not block, unfortunately, th* run while adnxtartg viewt aince if they art utcd to Mock the lunhght, they alto block the viewt In fact, theie devicei do block iolar raiaaoc behind window glanng. and the retuk u, obvtoudy. much of the beat remami ndoorr (Lechner, 1992) The advantage* of totenor thadaig device* rely on their capaMbbei to provide privacy, control glare, truulaOoo, mtenor aathetic*, they are let* expetuive than fixed overhang*. and eaty to maintain. replace, and operate Hipecialy dunng winter, where the tun angle would be low, and tixufama would penetrate deeply into room*, the u*e of memo) (hading devicet can be very iiteful to n a t i i e gtwe Venetian blind* or lightahetve* w iU give a tuce dutnbutaon of dayhgldmg while cortrohng glare Another option of die uie of Venetian bhndi u to put them between window glazxig (Tor double pane waidowt) I B B'a Help 4. Cluing One method of controlling run radiation penetration i* the uie of ddferent typei of g iu i for cHFcrent tun onentaboni (Andenen. 1984, Lechner. 1991) The mcident iolar radtatton. however, will reach 100 percent of ita vahiei if there u no g)aaog pretence at all it doe* not matter bow thin and clear the gLanng it, it ittll will abiorb, tram nut, and raradiate the incident tolar radiation in ruch away io that the radiation entering roomi w iU be leu than 100 percent Bancaly, there are three katdt of glazing available clear glaii, heal-ab* orbing glati. and heat-refleebve gjast 4.1. (Tear C la n In utxtg clear glazing, about 90 percent of the made tit tolar radubon will penetrate mdoon. However, clear glazing n very ute&il for a pulively healed budding. etpecialy dunrg the winter k u o q, became a aftowi the nxi to heat the mtenori Comreriely, there will be much heat penetratmg indoor* during rummer, which can caure <h»comfort, unlei* appropriate ahadng device* are uted. The tone km on i*. clear glaang can not be uted w a (hadmg device I S Fig. 5.11 The complete theory forms (continued). 91 H i t S h . i t l i H ' l M i l ' . l I 'c11111 ii 11» H i I f e m « uty 4.1. He at-Abtnrhang O lm L> hX * M M L . B a l i A l l I I * 1 * • » * , e c * 1 * , Fig 14 Sain *nwa> ewwnwtion Uiouiyi hu l tb ta b m y m n d * g la w io vt ek» rfrna Savoa W iln i DanM. " I k E w g O H g i Mw*±xx*“ 1983 Heat-^>iorbag | | t i i u one type of tested glanng which can be wed to reduce light traronastiae bid is tented el 4* ability to decree** heat gain. The tolar redubon will be absorbed about 30 percent, but then about 60 percent of t w iU be r era (hated tt do or Tbui th* total indoor beat gun reaches 80 percent of the original aicident tolar radiation (10 percent lets than clear g|uaig) m 1 1 1 4 1 | M.i'.k I 'r111ji111 Hi lf Hit urv EH* Help 4.3. H« at-Reflecting OIm i y Fig 15 ENacton d Rafladng Ffci Locaken on Heal Ti a anwaon Thiomyi D aikO lurv Sauce Wetaon. Donald. "ThaEnww Deagn Handiook," 1993 Thu glaang. which ha* a cortqg of metaJke onde or other material*, hat been very powerful in blocking undent tolar radwtioii, w hit mamtaming views racety The reBectance of th* glaang may reach 78 percent of modes* soltr rathataon, which it very significant to reduce heat gam through window*. Beat-Reflecting glait alto create* mages 'facades of other buildings* (maror effect) The <ii advantage of theie glarings, however, are that they do not differentiate between bgbt from the tim and tight bom the view, they filter out light al the tame, and they alto block winter tun. which is very needed durmg waiter Some kmdt of this glass may distort colors of the view, and darken mews (Watson. 1993) !• Fig. 5.11 The complete theory forms (continued) 92 I l i e M i: k [ 'i <k | i . h i i 11*-111 ili Ell* Help .... .. • • •• •• • £ _ • • • > • ; 4.4. il*ak-K.*fl*cting 1 H iit'A b io rU n i G lm Another opportune? to taka advaotag* ofbaal-abiorbmg g a ti and heat-rafiecting ^ u i ii to coordmate diem m a mated vmndow dengn Double-pane glaang u*mg heat-reflecting glaat on (he outer nde and heatebiorbmg Sian on toner aide of the wmdow ryituni, wnfa an ax layer m between, will pee a aatwfactory r**uk The uae of metalbc omda and other watehali for coahag ahaet* Ear refteckrt glaang nefacei hat been m y common m e t people have been developing thee buddnt appearance! leu expennveJy, and reducmg air condmonmg coata wntan the bidding! becaute the Sm-coated glaang may reduce beat gam ttgpificandy However, Anderson (1984) mggerted that if reducing heat gam ia enbeal, htet- mbiorbmg glaii and heat-reflectmg glaaa can help But he alio italed that * Such glata reducei iolar heat gam (etpecially heat-reflecting glatt) * They are aknott unnecei tary m north, north-northeait, and nort-northweit on the facadet. except m the laWude louth of 30 degree North, and for glare control * They are not recommended for louth facing window» in latitude touth or40 d e g r e e North * For louth, loutheaat and louth we it onentahon, vegetanoc and operable ihading device! we more preferable than glanng 1 9 M i r M - I ’.k I 'i Iti|r .till 11 * I ^ a l l n m y Ell* M*i» Kr r:.;t R « firiiu « i And Suggmted R iatliugi. Anderaon, Bruce (1984) *Paimre Solar Dengn Handbook. * Van Noitrand Remhold Comp ay. New York Benytnun, Stem .Reynold!, John R. (1992) "Mechanical and Electrical Equipment! for Buddx^p ' John Wiley And Sona, New York Crowther, RjchwdL (1994) 'Sim/Earth ‘ (-) Dans, Emit (1967). 'Sun Protection. An International Arcbtechral Survey.' Frederick A Praeger, Pubhthen. New York Faibow. M (ed). (1981) *En<nronmental Phytic* in Conitrucbon* Granada Pubkahmg Laiuted, St Albani, Herts Fry. Maxwell and Drew. Jane (1982) Tropical Archxecture m the Dry and Humd Zone I * Robert E. Kneger Pubkahmg Company. Malabar, Florida. Harkneii, Edward L (1978) 'Solar Radiation Control m Buddingi' Applied Science Pubkther LTD, London Hopkmioo. R G (1963) 'Architectural Phynci * Her Majeity’i Stationary Office. London 20 Fig. 5.11 The complete theory forms (continued). 93 Ilit' : if) rnf ii nj M <r> k \ ‘rmjr «nn H rl |> I li r m y H elp K ^ r m o i And S ii|g « it» t H u d in f i (Crmtuumd). Knowle*. Ralph L (1974) ’Energy and Form " The Ma**achu*eti* Institute of Technology, fourth printing (1980) Kukreja, C P (1978) “Trope » 1 Architecture * Me Or rw-Hill Book Co , Hew York Lam, WiQism M.C. (1986) ’Sunkghlmg a* Fonngiver for Architecture. “ Van Noitrand Ratnhold Comp my. New York Lechner, Norbert (1991) “ Heataig, Cooing, Lighting, Dengn Method* for Architect* “ John Wiley And Son*. Inc Mama, Edward (1979) The Paitrve Solar Energy Book * Rodale Prei*. Emmaui. Pa M oore, FuDer (1993) ’Environmental Control System* * M cGraw-Hill, Inc Olgyay. Aladar and Olgyay. Victor (1957) 'Solar Control and Shading Device* * Pnnceton Uruvernty Prett, Princeton Olgyay, Victor (1963) *Dettgn Weh Chmate ' Pnnceton Univernty Preit, Prmceton, N J 21 Pie Help Refvrvnca* And Suggerted Reading* (Centbraad). Roger*, Richard Jamet (1979). *A Computer-Aided Method for Shaduig Device Dengn and Analyn*,' a Maiter of Science Then*. Cornell Universdy Sebadarma, Effend (1995) 'Shading M ark A Computer b u ed Teaching Tool For Sun Shadmg Device* ' A mailer'* then* of Maiter of Building Science, School of Architecture, Univernty of Southern California, Lot Angelei Shaviv, Edna (-) “ Denfp Tool* for Solar Right* .Sun-Shade* Determmation ' National Painve Solar Conference. American Solar Energy Society conference Seokolay, S V (1980). "Environmental Science Handbook for architect* and budder* * Wiley. Hew York Wat*on, Donald (1993) The Energy Dengn Hand B ook' The American Inttttute of Architect*, Washington D C 2 2 Fig, 5 .11 The complete theory forms (continued). 94 Saarch Tapac: A sw ags Basie CaasidarajtieM Chart C%ar Glazing Iggerat«< . . B rta m al Shading P asieas . O luing Huat- Absitrhmg O a ts Ifaat-Ksflarting Class MoatKnflacting-iHnat Absorbing Class H oriuntal Shading ItStamal Shading D s tic n Introduction i li < n l h n | M i : k !> i: . 1 1 1 I fils H elp • ............. M S sarth Tapir: Lauvarad Orarhangs Natural Shading D ssirsi O rsrhangf Jtafaronca* Skadhm M ask Kkittin Sun Path Diagram Th* N aad for Shading D sviesi Transparent Overhangs Types of Sun Shading D svks Vartictd Shadings Fig. 5 .12 The search forms 95 BLUE C^Q SS/81U £ SHIEM3QF CONNECTICUT CORPORATE HEADQUARTERS,. North Mavpn - Gonnoctiout Dwinw UQHTSHEIVCS Destined by Th* Architecta Collaborative Inc , the south fat adc of this btaJdng it finished by a w het ofhgbtshelvet- L^hnKebrfi provide both escelenl dhtribubon of sunlight while maintaining nawnun glare, end thedutg with uncluttered views. Sow« Lam Wien M . C ' ' S u t t ^ i n g s t F v n g M i l e u tidbr t i H . " Y w i N o w in d B a r t a t d C o m p a r y . N—r Y a k , 1 9 8 6 1 1 1 jii i n N ( . 1 1 1 :;ii ,N'. |i x a m i l i :;| |i ai im ii in ia IA11 o h it I n u iin iN < ,| pie B»H*i| Detl|tt Help CALIFORNIA STATE BUILDING, Saw am onto - CalHomra 'A - D t w c HOLLER SHADES AfthoUgh 80 percent of fee building'* fatadet ere covered by glaemg etdenor refer shades, which are apphed on wert end east facades, reduce tolar radiance. The r o l* ihedet a n opertfed by a cornhnaboc o f photo teuton and ante clocks (alo w b c). At certaei tmnei. n o n are blocked totally but then devices are relatively nexpennve compared to b a d onet. they are kght and easy to mas* am and replace. Ptnodic masttenanct it raqtared Archstects Office of the Catfom a State Architect S ew ecW bnvD antkt |ed L * ' T he E nsrgy Oaiipi HandMoh.' The t a n k a i Inttti ta o l AictAarts Pieat. W adnidbn O.C. " 1 9 8 1 : - Fig. S . 13 Examples of building design. t n i l l m i n i , d i |i x a m i ’i i :;| ii A i t c i N i l n c i N i l n i m tt, . v c h i a i a i i i ’ I Elle B«*tldlwa PenlQtia Help C A R PtN Ttft CtMTLiR for tho VISUAL ARTS Cambridge - Mussuetiu’ iotls D*0ciiptiafv Fg0Cf«t* H a iY iiid U n i v e r s i t y . The window will of this buddwg » COY*rod by an agger at* type shading device, which block* sunh£it from horwontal and vertical drecbons D u depth of the demce is very useful to block the •unh^bt totally but at the w n t tune it restrict* maw* The eggcrate is not only very useful at blocking > untight but alio in reducing the amount of soUr heat penetration into the budding Architect Le Corbusier S owe* Waitwv Donald [ad 1." That net* Oaupt Handbook". T h# Ajiwfc«n Inrtiuta ol Aichdacii Pi«c. WjuhngtoA 0 C . 1993 IIUIIDINti 1 )1 SIGNS [I XAMPI f S| |CKVSIAI (AFHIOMAI| S i] EHe Building Design* Help CRYSTAL CATHEDRAL. Canton Orovn C.Uilornui D avies HEtLECTING GLASS Thu building u designed by John*on/Burge* Architactf Th* entire facade i* covered by reflecting glus which reflects its surrounding on the glass surfaces Located m Garden Grove, California, this gfau bidding reflects openness and uaty with its environment and bring* the outdoors tnlo the intenor) But the glass also creates glare for the occupants of adjacent buddings, and pedestrian* Soucs Walton Donald lad 1" Tha E nagp Demon Handbook'', Th* American In***# at ArcMacts Pw*s, W aihr^on D p . 1993 Fig. 5.13 Examples of building design (continued) 97 D MAR MALA BUILDINCJ. Jakarta - Indonesia D«ner O V tH H A M G S This budding u dengped by faul Rudolph and budt ip Jakarta. due capital oflndonejea Th* Dbanaala Office BpdApg haa venations on overhang poptaoae and orientation. which overhangs for eluidmg and ground-redacted kgf* for&anmahoc Facades of the bud Ang provide ihading and bud dmg reflected kghL According to a turvey on energy usage A Jakarta, ttui budding hai the one of fce loweit energy consumptions S e x # o r L « i W # m M C " S i * t g H l n g a t F a a p v « ( l « AicMeduia." Van NoWmd RrrVwld Company. Naw V a te . 1SB6 I illll l.'lfjl, I I I : III ,N' ; |l I I ' i | |l u w I Nl I I I . . Ill Ml I N . I HA I I ON III III IIINi.j EHe Building Deelpne Help LOW ENERGY DEMONSTRATION BUILDING. London England F A P R IC AWMIMGS For manmum benefk m aunny coodmoui, th* rectracuble awtangr in das buddasg can be adjusted as needed- Thu device it also relatrvaly meepensrvr and stay anprove budding appearance nicely The ewnmge should be large and opaque enough to gam the* mamntum capabdmee. S i u e a Lan. W l w i M C "S untiA tns ea Foasgtvei far A ic M a c tiM V a n N oPiand HanhoW C am pers. Now YoA, 19 Fig 5 13 Examples of building design (continued) EIH B n lM In t Q a a lg n a H elp 9 OFFICE BUILDING OMAHA. O m aha - Mobraska VERTICA L FIHS Id thif buldog, vertical flnt m e placed from Boor to ceiling and cover the facade* u curtain* Hut building h built a Omaha, Mebraika, de«gned by Leo A. Dily C , Omaha The vertical Sns 0 ve a good protection agamsl mnfcghl from the tide but n tw i me reatncted Sw eet D m . Eirat '‘ S in PtotaMon. wt Manakonal Aiohaeduiil Slavay." Fwdaiiek A . Ptaagai. Thfetihai. N w Yorir-WaMngton. 1367 m m ihn1* in |i k a m i i i m | mi ynui in; mi iai < o m c a n v i file Bulhllng Daalgaa Help REYNOLDS METAL COMPANY. Richmond - Virginia • v . . D*«c«; AQJU CTA BLE VERTICAL FJH S Adjuftable Bni which extend from door to Boor are applied to thu building The louver* are controlled photoelectricaty (blowing *un pontaon in order to lent run, Again, m tome at^Jea, view* am vary remitted Archgecti. Skidmore. Owning* and Meml. Mew York-Ctvcago Sqwce: Pam En*t "Sen pMadnvar k* mn+ Kr <4M HMC **4 Suvag." FiwM cIi A Pra*B V - FM jfahw , Nan Ya*k W aM m an. 1967 Fig. 5.13 Examples of building design (continued). R O B It H O IJS F Dwicc OVERHAMtS Dengned by Frink Ltyod Wngh*. die Robie Home h u dommant horizontal overhmgi that provide total thading for toulh> facing french doort Note that die terrace u A ided nicely The roof overhang on the right tide it large enough to iblde the balcony S o u rc e L a n . W t a n M C " S u d t f t n f l a t f o n w n i a f a A j c h t e t l i r a " V a n N o r t i a n d R e e T io td C o m p a n y . H a w Y a k 1906 Ella Building Deelgne b e Ip m i l l H I M ' . 1 1 1 M ( , N ' ; |l NJIMI'I I ‘.| | MI N A H A Ml M N I A i . A ( HI M I I I W I 11|| MEMARAMesiNIAGA (IBM Tower)* Selangor * Malaysia Davica: OVERHANGS The btaldng it detigned by T S Hamtah And Yeaog-KenYeing Thu 15-itory tall bialdaig placet t> tervvce core- on IU M it nd» to block direct rayi of th# mocraag npi The project ratpow et to 4 * tropical cfcnatc by plpcntg muhutory Utracpt ctrvad into the buiderg't matt Thg arotvtaptt dengped two typet of iolar control device* tie firrt device u atcreen of , dotely placed atunmwn rtript (wbcb block# m»(t of the tun), the t c c o o d device it a tun breaker of ahanaaum tlnpi « t farther w > *rt (that allowt m o r e to penetrate into intenori) S c x t c a P a a i o r v C W ta d A 'VNc h a v e h a d R i c o n t " M a c h 1993. Fig. 5.13 Examples of building design (continued). 100 »U U 111 I Al INI. WIN! H IW 14 N l M l n I J j/fr -i i ?i 1y&> II k*ip*»<ft*9Mil«(L<»Anpto*1U*el4a* A building in lo* Angela*. tiM e *omh feeing window and ihedmg device* overbuy (d— 4 ft), vertical (in* Q * - 4 ft). window width (w2=*2 ft), window height (h2=2 fl), wall height above window (hi =2 ft), and wall width betide the window (w l*2ft) 5*»i path daptm let Lot Armt**. Juw i1 M l l l l l l I A l l N l i W I N IM) W I I I ' ; AN!.I I I ! . v,-x C s V - :- (he thadvig iM*k d #w vartungt Tha thaAig na*fc ot lha aggciata* The *ha*i(i await «f Iha vaifcdtnt ITtha buddmg only employ* overhangt, 100% ahadatg w J be obtamed from and above 45 degree* vertical angle, and from and outnde 45 degree* horizontal angle for tin* 50% thading w iQ be obtaoied from 38 to 45 degree* for overhang* and from 35 to 45 degree* bar vertical G n* Fig. 5.14 Examples of shading design. 1 0 1 k J Hl l Ir I | W ! M I A U M I . W I N I M IW 14 N i i K I I I I Al 111)111 I < >:. ,*.Ni ,1 I I iiM pa» dapaaalot L p* (34.rhgHoalh e*A Sun p**l dapam toi LM Angataa, Jiaw 21 A budding m L«i Angelei. with a window dull faoe* 30 deg. weat of du« louth hai theie eharactentuc* overhang (d»4 ft), vertical fin* {Ml ft), wmdow width (w2“2 ft), window height (h2”= 2 ft), wall height above window (hi-2 ft), and wall width betide the w idow (w l=2 ft) ^ s i h i l l i t a i in < i w i n i h i w i o : . a n u i t : p V v ^ W ^ PTT7S Thadtadngm^iddiavarfiang* Tha abating m a a fc et itw --- i vaMcallh* Th* overhang would ibade the waidow totaly note 5 t c to 6 30 p ro {all day long) The fina would ihade the waidow totally from S a m to 11,30 a m and from 2 p.ra to 7 p » . SO % ihadng wtl b * obtained b o a 11.40 am. to 11.50 p ut and from 1,40 p m, to 2 pjn , whde 0 W ahadatg will happen from 11.50 a.m. to 1 40 p m The concluaion p. the eggcrate would ccanpktefy ahade thc window. Fig. 5 14 Examples of shading design (continued). 102 > ..I I Vr 1 i m n .Hi t • i il 1.1 , i m <\ - .. |...........r ~ - - [ - — 4ULTIAU GLA2JN6 S«0aO*w 1/Bn S O B 4 1/4n 88 78 3/8 *i aa 72 1/2n 86 87 * * • ---» » ------------- » - = -- 1/4 n 52 98 Dodda ; 1/2*i**<paoa 90 7 1 Tapia ; 1/4n**)pac* - AcqAc. tr^ m 1 i 1/4n a lp a ca 92 85 Acaytc, w/iaHaiing eoUng 1/4n m p aca 14 12 I | HOT A B S O R B IN G □an. Snda Gland H«l Abtarbaig (duirial O w IntUalng |doubN| 1/4*, 1/4n ) n a s re a o 78 47 59 Fig. 5 15 Table o f glazing form. EXTERNAL D EV ICES Fig 5.16 Table of shading coefficient form CuAara 10-20 S - 25 30 S O 35 1 j z 20 30 9 S O 50 ■ 75 64 Hm I Rm MV G Im i (odpradl Rod al Caddn ovadtanga C O n - » 70 PMaunad) <0 100 *0 40 57 a Conciata hood and E na 70-80 80-100 « ! 70 Lmmaiod hood IB 80 100 77 84 Voriitd louvata 70 80 10 90 45 65 ' 54 HmonW louv*« 70 80 19 S O 49 70 53 Suapandad fcuvatt sob 80 100 70 80 81 Fig 5.17 Table of effectiveness of shading devices form I ALGIERS . Alpna ATHENS. G il C A LC U TA . ImSa Fig 5 18 Table of latitude of cities form. 104 0600AM *60804594444215 . 14.1824140620732 060QAM -665787630066487 i - 390901165662444 [ IJ700AM ; *56313841611418 1113774424328868 I 1 00 00 A M 1*3002980832676 i 269969040482436 1 | O B tO D A M -57871278480806 140.0845625808137 1 [ iO tO D A M -4*2647224644652 52.2012123901019 1 1 1 00 A M -239667972013284 61 897324514701 1 I Noon 0 ; 66.9883633496711 I I 01O O PM 29(9667972013284 61 897324514701 1 02 G O PM 40 2547224644652 52 2012123901019 (BOO PM 97 871278480806 400845625808137 1 [ WOO PM 63002980832676 26 9569040482436 1 0500 PM 66 6313841611418 113774424929860 1 0500 PM 665787630066487 390901165662444 [ 0700444 ;66.0804594444215 14 1824140620712 1 Fig. 5 18 Table of sun path form. 105 pouhftve from fdi to p l o t button that help I 111 w I k i ' I t i f ,i ■ (■ l > I r 1 r 11 | 11 ,i 11 f II11 T t f M i i n v i A d i |r « n f o r * cH triii litiiw U t k i dat«; 1. Chooie a latitude value by alidng fee vertical acrol bar ahder to a d c m d latitude, eiher northern or louthem heaaiphere A Hit of latitude ofcibe* it ivadablt on a tableby efcckng Lathude* maim from Tablet menu ThaUM uda •c x d b a i.' ThaPW button ThaD aM M rctbar ThaOftton hutttti T h* Q m 2 Chooie a Certain date by tiding the hbnrOolat ictoll bar rider to a deaired data. The date can be Meo on a amall wndow above the rcrcD bar 3 Cick the Plot button once to plot a daily diagram A. J tyou wan* to plot a yearly dagram. ehck the Opkon button, and chek OK. Click ao to go baokto adady option.or Cancel to cancel opfeoea ; 5 Chek the OUaf buBento dean tha tctaan Fig 5.20 User’s guide forms 106 Tqplqt a ahgifrnf maak: 1 F r it,c k k ShadmgMaik from pul-down menu and chooia what katd of ik td h i maak option you wan* to atudy 2 Xou-iaap tbooar &•*««* Sfrndgic for a qua* look at a itw dng nwsk, agher foe overhang*., fin*, or aggpreie* 3 If you pac&r Inatanf S k ad ar hmpty dick tha kiwi of (hading maak decred Ckok OK oo the pop-up mettaga boa 4 If you want to aaplore any kind of ahading maak*. ekek from ether front the Novice or Advanced Opeoni, the Overhang, the Fara, or tha Eggcrate option, and choote tha rabo you wart to atudy Click OK 3 Click the Plot button to lie a daily diagram O r Option* to tee a yearty diagram, then cick the Shading Maak button. 6 Click the Clear button to dear the tcreen and go to other option* j s Id itpldrw *iiun|iM i: I Cick menu Examples from puB-down menu once end ebek once egwn Building Derign Menu 2 A new form wii wpptm. Chek Show Buildmgintau Bom pull-down m m an4 cfooi* t N d n g lo Be explored, m d cfeck once 3 If you went to see til buJde^s «t the tim e tent, chooie Show All Bteldiigi menu 4, To ewer D m picture teopfy ebek foe Cloec button on every picture, or click CUer Alt Budding* from foe pull-down menu 5 Click rile menu end dick Exit menu once to go beck to thotrwfo i erven Fig 5.20 User’s guide forms (continued). 107 : Tnjriwt **\y topic fro** the p n i r w 1 To m d my topic from thu program to a prater you need to dick my Ptkit btkton, w hdt u pre tent on nery fotm 2 You may not prat any turt priti diagram oir ihedng maik from thu ': uahiori To print my rim path diagram or thadrig riiaak or b o * ofthaad (any ahridmg n r ik rib • rim ehart) y#u may do ad fofrowt Fiat, you haiet plot a rim j(>rih dia^arn or my ihading maak darind. After the deared 4 i | m appear* on the ftrcen, preta PrintSSbn key from your computer’ ! keyboard Open trie Wnte program, of W*rd» for ‘ Wndowi Click Tarte" from E<rit puB-dottn menu from the program choaen. The diagram mD be plotted on the icrces. To print the tkagrwn nmply cbck Pnc* from File pufl down menu m d dick C >K The Aagram wA be prated Em from W ntt or Word* for Window* to go back to Shading M aik program. 3 Shadaigmadc option* cm b* prated daetdy from each form of Sharing Merit by ckckmg the pimt button. M nw lull ill H it I In ury O ' fcx to E 3 To n u ll th« Unory: 1. Cick the Theory rnnpu fron* the Help menu. Hm first page of the theory uni appear on the screen. 4 Cick the rnnl Topic from File pul-town menu if you want to prmi any form o f the theory 5 Qick the Ent menu to qxat Fig. 5.20 User’s guide forms (continued). 108 t. Click eabar tba Help button or ih iH 4 ) flow , which k p n i m on e*ery form - 2 In many caw* you may prio* many Help topic* directly from any Help topic ydo mill open. Fr6m l i t How To hd|p form, you can go to any apedfic topic yoututd by cfitkinfr aifrieran icootioie to a apedfic topafi button, or p t t e b k t g tfa* button itadC Fig. 5 20 User’s guide forms (continued). 109 5.2, Evaluation and findings 5 2 1 The Strengths o f the Program This program is a teaching tool for sun shading devices, stressing sun path diagrams and shading mask patterns. In general, the program reaches this goal and runs well. It covers almost every component of designing a solar shading device, from sun charts to shading masks completed with supporting tools such as a theory, a user’s guide, and others. The strengths of this program are: 1 Its capability to generate thousands of daily sun charts, 180 accurate annual sun charts, 65,700 accurate tables of solar azimuth and altitude angles, unlimited h/d and w/l ratios to generate unlimited shading mask patterns along with 360 degrees of possible window orientation. All of them can be plotted very quickly. An animation-like sun chart is generated as the “Plot” or the “Option” command button is clicked This feature is also applied to the shading mask options 2 A rectangular sun chart plotted on the main screen is easy to understand and clearly explains the sun’s movements during the day. It is more intuitive to read compared to a hemispherical sun chart. 3 A shading mask pattern superimposed on a sun chart also shows the shaded times directly and is simple to read and understand. 4. This program is simple to use even by beginners since it comes complete with a “Help" menu on almost every screen and because it is operated by simple operating command buttons. These features make users able to explore the entire 110 content of the program very quickly. And because it is a Windows-based program, those who are familiar with any Windows program will find no difficulty when they use this program 5. The program is a visual-based program. It is nice looking and the graphic materials on this program, even though they are not perfect, wilt help students to comprehend the topic faster 6. The program can be used not only as a teaching tool but also as a design tool Architecture students can use it to better their projects with shading device 7 The theory and building design examples included in this program are very useful to give a deeper knowledge of the sun shading devices to architecture students (users), and to raise their awareness of environmental and climatic considerations. Eventually, they will design better buildings in the future in order to create more comfortable and energy conserved living spaces. 5 .2 .1. The Weaknesses of the Program In addition to its strengths, this program also has some weaknesses as follows: 1 Since this program has many features and is written as a single large file it is a little bit stow in operation, especially for annual sun charts and plotting shading masks. 2. Some sun charts are confusing. This problem occurs when a user chooses latitudes below 24 deg. (North or South) and plot annual sun charts, since some o f the sun’s movements should be plotted facing in a different direction This is inherent in the Mazria approach and is probably why Mazria did not include those latitudes in his Elle Sh«J|"a M ilk Ex«wplt* E>q>l«)Q ... I»H t« B«lp I h r M t M H N U M A ' i b l * r r n | r - i r n SO U TH m * zi Sun-path Diagram LalM udK V i t i i n g A n g l i E m s m i Fig 5.21 Annual sun chart for 20 deg. North latitude. book Legends of data plotted are mixed with each other creating a chaotic screen The screen then, becomes difficult to read (Fig 5 21) To avoid this problem, for latitudes from 0 deg to 23 deg ., users are recommended to plot daily sun charts rather than annual sun charts, although the chaotic sun path diagrams are possible. They are also encouraged to note and study the date where the sun charts are plotted outside of the grid boundaries An explanation about this phenomenon is available under the “Explain...” pull-down menu. 3 Simitar problems occur when users want to plot a shading mask on those sun charts. As the sun charts above are difficult to read, it is also recommended that 112 users may plot only daily sun charts instead o f annual sun charts in order to avoid this problem. 4. Another weakness of this program in its “Shading Mask” option is that users need to test many shading ratios before they will find the most appropriate one to design their shading devices. This is a one-way process of creating a shading device. Users can not start designing their shading devices from sun charts since the program has no ability to plot overheated periods on the charts (in Olgyay’s method the overheated periods can be overlaid on a sun chart). But users may define desired shaded times before trying any h/d or w/l ratio and fit the shading masks generated to these times. 5 The print command in this program is basically a built-in print instruction in Visual Basic 3 .0 . It is a print form method Undoubtedly, the resolution of a print is dependent upon screen or monitor resolution. Furthermore, the sun chart and/or the shading mask plotted on the screen can not be printed directly Instead we must use another Windows program to print the graphs This print method may be improved in the future to generate better printing results 6. There are also many imperfect pictures in this program resulting from scanner images and other bitmap files caused by screen resolution This program would be nicer if those pictures could be perfectly shown on the screen because good pictures, especially pictures of building design, has a great effect on graphically oriented individuals. 113 CHAPTER 6 CONCLUSIONS AND RECOMMENDATIONS 6.1. Conclusion This thesis and the computer program (SHADING MASK) completed demonstrate a teaching tool for sun shading devices and stimulate architecture students and those who are interested in learning sun shading devices. We recognize that only cold climate areas do not need shading. Thus, sun shading devices are very important to minimize heat gain, to control daylighting, and to protect walls from rain An understanding of these devices will encourage their application on projects in order to minimize operating costs and save energy Furthermore, buildings will be created based on climatic and environmental considerations to prepare better living spaces in the future. The rectangular sun chart is easier to perceive and understand than the hemispherical sun chart. Students will effortlessly understand how the sun moves in space as they see it daily For example, for the northern hemisphere, during December, sun angles will be low in the sky This circumstance is visualized nicely on the screen. Unfortunately, for some dates, where azimuth angles are greater than 90 degrees, an observer may notice that the sun does not rise and set on the same vertical plane. This phenomenon is not easy to depict. In fact, for those dates, the sun may rise and set at a certain position behind the observer. For latitudes under 24 degrees, either northern or 1 14 southern hemisphere, the annual sun charts on the screen become difficult to read This problem can be avoided by plotting daily sun charts The SHADING MASK program shows that using a well-designed computer program to teach, and re-teach when necessary, the use o f sun shading devices is more understandable, clearer, and more interesting than reading a book of the same topic. The program explains the basic theory of solar control; generates sun path diagrams; allows the design of overhang, vertical fins, and eggcrate shading devices; calculates solar angles and shading masks; and provides case studies of actual buildings. Finally, SHADING MASK is a demonstration of how to integrate theory into a teaching or simulation tool to make important solar control information easily accessible to designers, students, and architects. 6.2. Recommendations First of all, an improvement o f this program is recommended. As I described in the previous chapter, improvements can be made on shading mask options, where users may design their shading masks directly by reading shading angles needed from the sun charts. Designing a shading mask directly from the program will improve the program greatly. Also, I would like to propose to include this program into any CAD program, where users can apply it directly while they are designing their projects by using their computers The future improvements may include plotting the sun charts and shading masks in three dimension (3-D charts), and an animation of the sun’s movements. The sun shading device is only one tiny piece o f environmental design. There are still many aspects of environmental design that can be written in the future. Natural 1)5 ventilation systems, energy conserving designs, and automated buildings are only some feasible topics of other teaching tools. It is important in using a computer program as a teaching tool that, the program is friendly enough to use Lecturers should encourage their students to use the program or use the program to help them in teaching the topic, or make the program a part of their regular class meetings In other words, teaching tool programs will be deserving, useful, and effectual only if they are in use. 116 REFERENCES Anderson, Bruce (1984). Passive Solar Design Handbook. Van Nostrand Reinhold Company, New York. Benjamin, Stein & Reynolds, John R. (1992). Mechanical and Electrical Equipments for Buildings. John Wiley & Sons, New York. Bork, Alfred (1981). Learning With Computers. Digital Equipment Corporation, Bedford, Massachussets. Cornell, Gary (1993). The Visual Basic 3 for Windows Handbook. McGraw-Hill, Berkeley, California. Crowther, Richard L. (1994). Sutt/Earth. - Danz, Ernst (1967). Sun Protection. An International Architectural Survey Frederick A Praeger, Publishers, New York Finbow, M. (ed), (1981). Environmental Physics in Construction. Granada Publishing Limited, St. Albans, Hertz. Fry, Maxwell & Drew, Jane (1982), Tropical Architecture In the Dry and Humid Zones. Robert E Krieger Publishing Company, Malabar, Florida. Gurewich, Nathan and Gurewich, Ori (1993) Teach Yourself Visual Basic in 21 Days Sam Publishing, Indianapolis, Indiana. Harkness, Edward L. (1978) Solar Radiation Control in Buildings Applied Science Publisher LTD, London. Hergert, Douglas A. (1993). Visual Basic 3.0 Programming With Windows Applications. Random House Inc., 2nd Edition, New York. Hopkinson, R.G. (1963). Architectural Physics. Her Majesty’s Stationary Office, London. Hrisafovic, Serge (1992) A Computer Program to Teach Passive Solar Design. A Master of Building Science Thesis, University of Southern California. Knowles, Ralph L. (1974). Energy and Form. The Massachusetts Institute o f Technology, fourth printing (1980). Kukreja, C.P, (1978). Tropical Architecture McGraw-Hill Book Co , New York. 117 Lam, William M.C. (1986). Sunlighting as Formgiver fo r Architecture. Van Nostrand Reinhold Company, New York. Lechner, Norbert (1991). Heating, Cooling, Lighting, Design Methods fo r Architects. John Wiley & Sons, Inc. Mazria, Edward (1979). The Passive Solar Energy Book. Rodale Press, Emmaus, Pa. Moore, Fuller (1993). Environmental Control Systems. McGraw-Hill, Inc. Olgyay, Aladar & Olgyay, Victor (1957). Solar Control and Shading Devices. Princeton University Press, Princeton. Olgyay, Victor (1963). Design With Climate Princeton University Press, Princeton, N J Rogers, Richard James (1979). A Computer-Aided Method for Shading Device Design and Analysis, a Master o f Science Thesis, Cornell University Shaviv, Edna (-). Design Tools for Solar Rights dr Sun-Shades Determination. National Passive Solar Conference, American Solar Energy Society conference proceedings. Shaviv, Edna & Yezioro, Abraham {1994). An Integrated CAAD Tool fo r Evaluating Solar Rights and Shading Requirements in an Urban Environment. 19th National Passive Solar Conference, American Solar Energy Society conference proceedings. Szokolay, S.V. (1980). Environmental Science Handbook for architects and builders Wiley, New York Watson, Donald (1993). The Energy Design Hand Book. The American Institute of Architects, Washington D C. - (1993). Microsoft Visual Basic, Language Reference. Microsoft Corporation. 118 INFORMATION TO USERS This manuscript has been reproduced from the m icrofilm master. U M I films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margin* and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the bade of the book. Photographs included in the original manuscript have been reproduced xerographicalty in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. A Bell & Howell Information Company 300 North ZeeD Road. Ann Arbor, M l 48106-1346 USA 313/761-4700 800/521-0600 UMI Number: 1376512 OKI Microform 1376512 Copyright 1995, by UMI Company. All rights reserved. This aicroform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, HI 48103

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Asset Metadata

Creator Setiadarma, Effendi (author)

Core Title Shading mask: a computer-based teaching tool for sun shading devices

School School of Architecture

Degree Master of Building Science

Degree Program Building Science

Degree Conferral Date 1995-05

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

Tag architecture,education, technology of,information science,OAI-PMH Harvest

Language English

Contributor Digitized by ProQuest (provenance)

Advisor Schiler, Marc (committee chair), Kensek, Karen (committee member), Noble, Douglas (committee member), Schierle, Goetz G. (committee member)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c18-4836

Unique identifier UC11357407

Identifier 1376512.pdf (filename),usctheses-c18-4836 (legacy record id)

Legacy Identifier 1376512-0.pdf

Dmrecord 4836

Document Type Thesis

Rights Setiadarma, Effendi

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