Site Selection and Design By: Sophia Warne-Rowe and Chelsey Glidden
Table of Contents Site Selection and Design
1-2
Vernacular Architecture
4-6
Passive Heating and Cooling
7-10
Passive Systems
11-14
Climate Types
15-18
Casa Batllo
19-20
Government Canyon Visitor Center
21-24
Bibliography
25-26
SITE SELECTION AND DESIGN In recent years, architects have become more dependant on technology to heat and cool buildings. They have stopped considering the more natural ways that this process can be done. By researching the climate of the building site, architectss can design sustainable buildings that take advantage of site temperatures, solar paths, and wind patterns. This is the idea behind passive cooling and heating. Passive heating and cooling for a building cuts back on energy usage and makes the design cheaper in the long run. One way that architects can take this ecofriendly process into consideration is to consider the climate, landscape and the positioning of the building and how it can affect the internal temperature of the space greatly.
1
2
SITE SELECTION AND DESIGN
VERNACULAR ARCHITECTURE
3
Cultures around the world have adapted their architecture in response to their surroundings, evolving over time in response to the native landscape and climate. Native cultures were often constrained to using local materials and figuring out the best ways to create comfortable living conditions without the use of modern technology. By looking at vernacular architecture, designers today can learn how to design with the landscape and climate in mind, while creating more sustainable buildings. Historic approaches to keeping a space adequately cooled/warm always used passive heating and cooling methods because they did not have the technology we do today. Because of the vast varieties in climate, people adapted different methods to build their spaces. In the Arctic, people would build Igloos. The thick ice blocks provided a form of insulation and the body heat from the occupants provided a source of heat. High steppes, built in central Asia, were more of a conventional house shape with thick felt walls. The difference, however, was that they placed a hole at the top of the roof to provide an exit for the smoke from the fire they placed inside of the space. Another method of construction, found in North America, were tepees. The structure consisted of buffalo hide that was placed over a frame which trapped in the smoke from the fire (Bainbridge).
4
VERNACULAR ARCHITECTURE
VERNACULAR ARCHITECTURE Further examples of vernacular architecture that respond to the environment are mediterranean building designs, such as those in Greece, and traditional Malay houses of the tropics. Vernacular architecture on the Greek island of Santorini, responds to the warm sunny climate through its use of white exterior materials to reflect sunlight. It also uses heavy, thick construction as insulation, with small windows and openings, as well as light wood roofing to allow for ventilation. Houses of the Malay indigenous population in the tropics are examples of architecture that responds to the tropical climate. These buildings are elevated, allowing for ventilation underneath and protecting the building from surface water. The walls consist of lightweight materials such as bamboo screens, with overhanging eaves that provide ample amounts of shade. The roof is steeply pitched often with vents to allow for air circulation throughout. The roof is made from layering palm leaves which are water resistant and insulative. The palm is loosely layered to create air pockets, and it has very little thermal mass so it does not retain solar heat. (Hyde) 5
Sketches of vernacular house shapes (left), and traditional mediteranean home design (right).
This diagram of a traditional Malay house, shows the complex strategy used for passive ventilation.
"IF DESIGN CAN'T MAKE PEOPLE HAPPY WITH THE PLACE THEY'RE IN, WE CAN'T DO IT WITH TECHNOLOGY."
-BOB HARRIS, LAKE FLATO ARCHITECTS
6
7
PASSIVE HEATING AND COOLING: Modern methods of insulation and technology such as doublepaned windows help create more energy efficient buildings. Double-paned windows trap air between the panes of glass, making it harder for the exterior air to enter the building and vise versa. (Anthony Adams) These are examples of how to passively control internal temperatures in a building, however the best passive heating and cooling strategies take into account the solar, wind, and weather patterns of the site. The sun plays the most important role in passively heating a building, so it is important to keep in mind its effects on certain materials. This is especially
important when trying to increase the level of heat admittance into a building because some materials are able to store heat more easily than others. For example, materials such as concrete, stone, brick, and tile have a have a high thermal mass. This means they are able to retain heat from the sun and release it into the interior of the building to warm it up. Color also plays an important role in passive heating because darker colors absorb more light. For example, painting the interior walls a darker color and using dark materials will increase the amount of heat inside the building. These strategies should be used in cool climates to create a warming effect and decrease the need for mechanical heating.
8
PASSIVE HEATING AND COOLING
9
In terms of keeping a building on the cooler side, the exterior material and color choice should be thought of in the opposite way. Choosing a material that is not good at absorbing heat will keep the light from being emitted into the building at a later time. The color choice should be lighter because the lighter a color is, the less light it absorbs. Because of their reflective qualities, light colors should be used on the exterior in hot, sunny climates. In areas that alternate between cool and warm periods, the architecture should account for the seasonal changes of the sun. Light, reflective materials should
be used where the high summer sun reaches, and dark absorptive materials for the low, winter sun. (Olgyay) Along with the sun’s rays, the internal load of a building should also be considered. Depending on the building, the internal load to consider can consist of people, cookware, different machinery, and lighting. Lights and appliances are another source of heat from internal loads. To decrease the amount of heat from these, it is ideal to buy energy efficient appliances and depend more on natural sunlight to light the building instead of artificial light.
Focusing on the exterior is just as important as focusing on the interior. Window orientation, roof overhangs and glazing on windows can prevent the sun from coming inside during the hotter months. Because the sun is higher in the sky in the summer months, the overhangs prevent the harsh rays from entering the building. Landscaping can be a source of passive cooling as well as building design. Water features and greenery can increase humidity and create cooling breezes, while trees offer wind and sun protection. Placing deciduous trees on the
property can provide shade in the summer and allow the light inside in the winter. According to David Johnston, “Mature tree canopies reduce the average temperature in suburban areas about 3 degrees Fahrenheit, compared with newer areas with no trees.�
10
PASSIVE SYSTEMS: Passive heating and cooling can be broken down and thought of as three different kinds of systems. SYSTEM 1: The first system is called the “Direct-Gain System”, where the hot/cold air “transfer occurs inside the interior of the building”. The simplest way to approach this system is to distribute the thermal mass around the building. This will provide for the best conditions of balancing the heating and cooling. By placing thermal mass (materials that have the ability to absorb heat) around the building, it gives more places for the sun to be able to transfer heat. This system, however, would require more glazing than the other ones because the sun’s rays would need more positions to enter the space. It is also better, when working with this system, to incorporate lighter colors. “While this reduces direct absorptions, it helps reflect light onto a greater surface of the distributed mass” (58) (Bainbridge). The lighter colors also create less glare than the darker colors would with the harsh contrast of bright light against a darker surface. When it is nighttime the cooling is also more effective because the heat was not as concentrated, making the radiation of the heat into the air move quicker. 11
12
PASSIVE SYSTEMS
13
SYSTEM 2: The second system, the “Indirect-Gain System” happens when the hot/cold air is transferred at the exterior of the building through the use of a “thermal wall” or a “roof pond”. In order to achieve a thermal wall, a portion of the building’s exterior would need to be adapted to “provide the thermal collection, storage, transfer, and control function” (67)(Bainbridge superscript). To make a roof pond, usually steel decking is placed over water because it has a high heat absorption rate. The steel would
heat up and the heat would radiate into the water, which would then be emitted into the building. In the winter, to avoid the metal from absorbing the cool air at night, “movable insulation” is placed over the metal. This also can be useful in the summer because it can shade the metal during the day when it is hot and be moved aside so the metal can absorb the cool night air and cool down the building. This method of Indirect-Gain systems is generally the most effective.
SYSTEM 3: The final system that can be used to passively heat and cool a building is the “IsolatedGain System” which transfers the hot/cold air outside of the building through the use of an additional architectural element (ex: “sunspace and “thermosiphon”). To take advantage of a sunspace, it should face the equator. The large vertical glass panels allow the sun to come into the space during the day, but can be closed off from
the rest of the building at night when it gets colder. An overhang and extra thermal mass (i.e. window coverings) on the sunspace can be used to keep the space from overheating in the summer months. Another important factor is to allow the space to have vents at the top and bottom of the wall that is shared with the rest of the structure. The top vents will allow the hot air to be transported into the building, while the cool air will exit through the lower vents. 14
COMFORT FACTORS: There are four factors when considering the comfort of a building’s inhabitants. Air temperature, humidity, air movement, and solar radiation. (Hyde) It is important to consider all of these factors when determining the most effective ways to sustainably heat and cool a building. The strategies for passive heating and cooling vary depending on the climatic conditions and the building’s context. The world can be divided into 3 climate zones, tropic, temperate, and polar. These zones can be further categorized into climate types, for example: cool, moderate, hot dry, and hot humid areas. COOL CLIMATES: Cool climates require a focus on passive heating, meaning heat conservation is the most important factor. To take advantage of natural thermal energy, the building should be oriented to take advantage of southern sunlight, with primary windows on this side. Other important factors are the need for insulation with thermal mass reducing heat loss and storing admitted heat. (AICCM) Protection from cold winds is also important, so a location such as at the base of a hill or on a S/SE facing slope of a hill. (Olgyay) 15
16
CLIMATE TYPES
17
HOT-DRY CLIMATES: In hot, dry climates the absence of humidity and clouds creates extreme fluctuations between day and night temperatures. This means is is important to have effective, passive cooling during the day, and mass insulation to protect against cool nights. Three methods for passively cooling the building in the summer are air, evaporative cooling, and mass. (Hyde) Using air flow is an effective strategy at night for bringing in cool air, but isn’t as effective during the day when exterior temperatures are high. Combining the use of night-time air with building mass is also effective. Using heavy, thick materials creates more building
mass, which absorbs the night-time air and prolongs its cooling effect. Thirdly, evaporative cooling is effective for lowering the temperatures of a building. This can be achieved through thoughtful landscaping around the building, however this option is not always a sustainable option because of its use of water resources. A building design that is effective in encouraging evaporative cooling is by creating a central courtyard that increases air flow and takes advantage of the cooling effects of exposed ground. It also provides a shaded outdoor space, adding to the comfort of the inhabitants.
HOT-HUMID CLIMATES: Hot and humid climates such as the tropics are found near the equator, and do not fluctuate greatly in temperature like temperate and drier climates. They maintain steady, high temperatures which means passively cooling is the most important factor when considering a sustainable approach. This climate is characterized by changes in rainfall and monsoon activity, which means surface water and rain conditions must also be considered. (hyde) The high environmental humidity means evaporative cooling is not an effective strategy. Therefore air flow and shading are the most important strategies for passive cooling. Effective building designs here should take advantage of natural shading from trees, and take advantage of passive ventilation. Effective strategies for passive cooling are designing with light weight materials and structure, with large openings and windows to encourage airflow. Raising the building above the ground is another way of increasing airflow, while also protecting the main part of the building from surface water. Overhanging roofs and shaded verandas also add to the cooling effect, and are
more essential than the walls. (Olgyay) MODERATE CLIMATES: The moderate climate type consists of climats characteristic of both subtropical and temperate.This zone does not have as strict site requirements, but requires an understanding of designing for both warm and cool temperatures. There is less of a need for cool airflow, which allows for the building to be placed lower on a slope, but it should still be a consideration because of the warm summer months. In this climate the building will need strategies for passive heating and cooling, including the use of shade, while still allowing for solar heat gain. Adverse climate elements include rain, snow, cold winter, wind, summer heat, and high humidity. The important objectives for designing in this climate should be minimizing heat loss and maximizing solar access in the winter, while minimizing solar gain and utilizing ventilation in the summer. Ways to accomplish these objectives are using good insulation, with large windows facing the winter sun. For the summer, overhanging eaves, roof insulation or ventilation, and large openings for cross ventilation are important. (Hyde) 18
19
CASE STUDY 1: One example of a building that uses passive heating/cooling is the Casa Batllo, located in Barcelona, Spain, by Antoni Gaudi. The production of glass around the time his design was built (1870s) was improving, so Gaudi used that to his advantage and used different types of glass on the north and south sides of the building. He also varied the amount of glass used on both sides as well, knowing that it would affect the internal temperature of the structure. In terms of building materials, “As a highmass building of stone, masonry, and tile, it has all the elements of a good direct-gain building except for good insulation, which was not available at the time” (Bainbridge,56). To increase the airflow in the building, he also designed the house to have an open courtyard and, “a complex system of openings
set in the outside and inside façades of the building, thus making the air run all over the flats producing a crossed ventilation” Guardiola,706). The open courtyard acted as a “light well”, letting the sun heat the interior. It also allowed fresh air to come through the main parts of the building. Further planning went into the design when Gaudi thought of how the windows could move to increase the amount of heat that flowed into the space. He made the windows directional so that it would open towards the hot air. This creates less resistance, granting the hot air easier access inside. The design included cracks in the doors and windows, and through the wood so that when things were more closed off, air would still be able to circulate from room to room.
CASA BATLLO - ANTONI GAUDI
"NOTHING IS ART IF IT DOES NOT COME FROM NATURE." - ANTONI GAUDI
20
CASE STUDY 2: The Tim and Karen (Government Canyon) Visitor Center by Lake - Flato Architects is another example of a sustainable building that emphasizes passive heating and cooling. The designers took into account the site’s location, studying the wind, solar, and weather patterns which would affect the building’s operational costs. The visitor center was also built using local and recycled materials including local hill-country stone, salvaged and locally harvested Texas cedar, and high recycled-content steel. The goal of the design was to create a modest building that had a low environmental impact, utilized the site’s natural climate conditions, and employed strategies for water-conservation. Government Canyon, is located in Helotes, Texas, which means the climate is dry and arid, hence the importance of water-conservation. Water conservation is especially important to the site not just because of the dry climate and scarcity of water, but because of the sites proximity to the Edwards Aquifer recharge zone. This means the rocky formations of the earth here act as a natural filtration system as surface water becomes groundwater.
21
22
GOVERNMENT CANYON VISITOR CENTER
The building is also sustainable in its use of passive methods for heating and cooling. The thin profile of the building utilizes natural airflow and daylight. Large, overhanging eaves offer protection from the harsh sun, screens allow for cross-breezes. Rolling, wooden doors are moveable to modify the buildings exposure to the elements, depending on seasonal and diurnal changes. The metal roof offers sun protection while also acting as a gathering device for collecting rainwater. Operable, double-hung windows allow for passive ventilation and cooling, while the large overhangs protect them from the sun. The architects explain: “90 percent of occupied spaces enjoy effective daylight and views, 100 percent of the spaces of ventilation control�. Porches on the south admit cooling breezes during the summer, while 23 moveable walls on the north block cold winter
winds. The elevated structure allows for uninterrupted surface water, while the native garden in the courtyard utilizes drip irrigation from the roof. A courtyard entry design encourages cool airflow throughout the building, and shade trees protect the building from the harsh, western sun. A fly-ash, concrete slab passively heats the colder office rooms during the winter, absorbing solar energy and releasing it as heat. The designers reduced the building’s environmental impact further by providing a large porch and outdoor space for activities, lowering the need for conditioned floor space. All of these strategies show how the Government Canyon visitor center is an excellent example of sustainable building design, which takes advantage of climatic conditions to reduce its environmental impact.
GOVERNMENT CANYON VISITOR CENTER
"THE APPROACH IS TO FIT INTO THE NATURAL ENVIRONMENT. TO FIT TOGETHER HUMANS, NATURE, AND CLIMATE IN SIMPLE AND ELEGANT WAYS. THIS IS THE BASIS OF DESIGN THINKING." -BOB HARRIS, LAKE FLATO ARCHITECTS
24
BIBLIOGRAPHY Adams, Anthony. Your Energy-efficient House: Building & Remodeling Ideas. Charlotte, VT: Garden Way Pub., 1975. Bainbridge, David A., and Kenneth L. Haggard. Passive Solar Architecture: Heating, Cooling, Ventilation, Daylighting, and More Using Natural Flows. White River Junction, VT: Chelsea Green Pub., 2011. “Bioclimatic Design and Passive Solar Systems.” Center for Renewable Energy Sources and Savings. Accessed January 13, 2017. http://www.cres.gr/kape/energeia_politis/energeia_politis_bioclimatic_eng.htm. Guardiola, Uson, and Cunill De La Puente. Passive Solar Design in Antonio Gaudi’s Domestic Architecture. Guzowski, Mary. Towards Zero-energy Architecture: New Solar Design. London, U.K.: Laurence King, 2010. Hyde, Richard. Climate Responsive Design: A Study of Buildings in Moderate and Hot Humid Climates. London: E & FN Spon, 2000. Johnston, David, and Kim Master. “Solar Energy.” In Green Remodeling: Changing the World One Room at a Time, 247. Gabriola, B.C.: New Society Publishers, 2004. 5 Olgyay, Victor, and Aladar Olgyay. Design with Climate: Bioclimatic Approach to Architectural Regionalism. Princeton, NJ: Princeton University Press, 1963. “Passive Climate Control for Cultural Institutions.” 25-38. Australian Institute for the Conservation of Cultural Material. Accessed January 13, 2017. Zhu, Jie, Hoy-Yen Chan, and Saffa B. Riffat. Renewable & Sustainable Energy Reviews. 2nd ed. Vol.14. Oxford: Elesevier Science., 2010. 781-89. Accessed January 11, 2017.
25
PHOTO SOURCES: https://s-media-cache-ak0.pinimg.com/736x/ee/13/10/ee13103beaecefadc187427d0e563c6f.jpg http://people.virginia.edu/~ag7rq/Spain/CasaBtllo/DSC05105.JPG https://phillipinbeijing.files.wordpress.com/2010/10/img_1928.jpg http://www.hbc333.com/data/out/141/47017225-landscape.jpg http://www.loe.org/content/2013-10-25/25-bigstock-morning-fog-in-dense-tropical--27061052.jpg
http://www.vimedya.com/8/2015/02/glamour-interior-design-nuance-with-curved-wall-design-that-seems-warm-nuance-inside-the-house-it-has-brown-granite-floor-seems-nice-design-that-decorated-with-wooden-furniture-inside.jpg http://3.bp.blogspot.com/--ZuYkjNfQ7M/UIC1ObuHIcI/AAAAAAAAFcM/w0AyuPDDqOM/s1600/18.JPG https://upload.wikimedia.org/wikipedia/commons/b/bd/Afternoon_sun_in_Mamfe,_Cameroon.jpg http://bucurestifm.ro/wp-content/uploads/sites/2/2014/07/Soare-meteo.jpg https://unsplash.imgix.net/12/sun-trees.jpg?q=75&fm=jpg&s=b06693f0dea63e1634aed2ad6228bf71 https://aos.iacpublishinglabs.com/question/aq/1400px-788px/dry-climate-definition_71691924-ab59-4293-9ad56a15618e3f64.jpg?domain=cx.aos.ask.com
BIBLIOGRAPHY
http://www.perivolas.gr/wp-content/uploads/2013/03/Screen-Shot-2013-03-09-at-18.09.19.png
http://ds0ucpy89hlve.cloudfront.net/images/made/images/remote/http_s3.amazonaws.com/www.travelsouthusa.com/ STATES/South_Carolina/From_SC/SC_Overview_Page_1_1400_933_s_c1_c_c.jpg http://images6.fanpop.com/image/photos/34500000/Green-Forest-green-34594086-5000-3333.jpg http://miriadna.com/desctopwalls/images/max/Low-sun.jpg
26
Sophia Warne Rowe • Chelsey Glidden • Design 6 • Spring 2017 • Philadelphia University