Idea Transcript
NJ GREEN BUILDING MANUAL
NEW COMMERCIAL UPDATED 5-MAY-11
Building Orientation What is Building Orientation? Building orientation refers to the way a building is situated on a site and the positioning of windows, rooflines, and other features. A building oriented for solar design takes advantage of passive and active solar strategies. Passive solar strategies use energy from the sun to heat and illuminate buildings. Building orientation and building materials also facilitate temperature moderation and natural daylighting. Active solar systems use solar collectors and additional electricity to power pumps or fans to distribute the sun's energy. Heat is absorbed and transferred to another location for immediate heating or for storage for use later. Water, antifreeze or sometimes air circulates to transfer heat. 1 Unlike active solar strategies, a passive design does not involve the use of mechanical and electrical devices, such as pumps, fans, or electrical controls. Passive solar heating makes Passive Solar Function Example Construction/Material/Action use of the building Collect South-facing glazing components to collect, store, Store Masonry, water, other mass distribute, and control solar Distribute Radiation, convection, other natural heat transfer heat gains to reduce the Control Light shelves, insulation, light-shaded paints demand for fossil fuel2 powered space heating. Table 1 - Building Components and Passive Solar Functions Passive solar heating strategies also provide opportunities for daylighting and views to the outdoors through wellpositioned windows. The goal of passive design is to maximize solar gain while minimizing conductance. 3 Passive cooling removes or rejects heat from the building, keeping temperatures cool. Avoiding any mechanical operations to moderate temperature achieves energy and cost savings by alleviating the cooling load demanded. Shading devices can also reduce unwanted solar gains by blocking the sun during the summer months, while natural ventilation, which relies on natural airflow and breezes, can reduce the need for mechanical cooling when the building is occupied (see Glare and Heat Gain Reduction strategy). The following five elements constitute a complete passive solar design. Each performs a separate function, but all five must work together for the design to be successful: aperture, absorber, thermal mass, distribution, and control (see Figure 1). 4 1
US DOE | EERE. http://www1.eere.energy.gov/site_administration/glossary.html (accessed April 30, 2011). Whole Building Design Guide. Passive Solar Heating Introduction. http://www.wbdg.org/resources/psheating.php (accessed April 30, 2011). 2
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Selkowitz, Stephen. 1999. High Performance Glazing Systems: Architectural Opportunities for the 21 Century. Ernest Orlando. Lawrence Berkeley National Laboratory. Berkeley, CA. http://gaia.lbl.gov/btech/papers/42724.pdf (accessed June 6, 2010). 4 US DOE | EERE. Energy Savers: Five Elements of Passive Solar Home Design. http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10270 (accessed March 22, 2010).
NJ GREEN BUILDING MANUAL
NEW COMMERCIAL UPDATED 5-MAY-11
How to Optimize Building Orientation It is best to incorporate passive solar systems into a building during the initial design. Passive solar systems utilize basic concepts incorporated into the architectural design of the building. They usually consist of: o Rectangular floor plans elongated on an east-west axis o Glazed south-facing wall o Thermal storage medium Figure 1 - Five Elements of Passive Solar Design, 2009 exposed to the solar radiation (Source: US DOE | EERE) o Light shelves/overhangs or other shading devices which sufficiently shade the south-facing elevation from the summer sun; south elevation overhangs should be horizontal while east and west elevations usually require both horizontal and vertical overhangs 5 o Windows on the east and west walls, and preferably none on the north walls In addition to passive solar and energy-conserving strategies, active solar systems can be integrated into a building's design and systems. Buildings designed to serve as active solar collectors should not be shaded by nearby trees or buildings and should have solar arrays or roof area facing south. Both passive and active solar collectors should be oriented at the angle of your location’s latitude (in New Jersey, this is approximately 40°N). Examples PNC Bank, Summit NJ www.scbp.org/member/documents/pnc.pdf Cambria Office Facility Ebensburg, PA http://www1.eere.energy.gov/buildings/windowsvolumepurchase/pdfs/r5_windows_commercial _buyers_fact_sheet.pdf McKay Center - University of Wisconsin Arboretum, Madison WI http://www.ecw.org/wisconsun/learn/cs_mckaysolarthermal.shtml 5
Watch, Daniel and Deepa Tolat, 2010. WBDG. “Sustainable Laboratory Design.” http://www.wbdg.org/resources/sustainablelab.php (accessed August 9, 2010).
NJ GREEN BUILDING MANUAL
Benefits
NEW COMMERCIAL UPDATED 5-MAY-11
Related Strategies
o By relying on solar energy, a renewable, nonPhotovoltaic Systems Solar Hot Water Heaters polluting energy source, passive and active solar Glare and Heat Gain Reduction designs do not generate greenhouse gases and slow Daylighting fossil fuel depletion. o Passive solar buildings can respond to changing weather conditions and connect occupants to the natural environment. o Passive solar buildings provide daylighting, which has been linked to increasing occupant satisfaction and productivity. o Passive solar buildings use thermal massing to reduce temperature swings and produce a higher degree of temperature stability and thermal comfort. o Reduced heating and cooling costs through natural heating/cooling cycles and using materials enhanced for penetrating, absorbing or releasing solar radiation. Costs The initial cost of passive design elements depends on the element. Some cost the same (e.g., light exterior walls for cooling) or only slightly more than conventional building costs (e.g., light shelves designed to control sun penetration). Some cost considerably more (e.g., interior thermal mass materials such as stone and brick). However, these measures can lower operating costs. Compared to passive solar systems, active solar systems often have a higher initial cost and longer payback period, which vary widely depending on the size and the specific type of technology used. 6 However, current federal and state tax credits and rising energy costs make active solar systems an economic alternative to conventional systems. 7 For more information on cost and energy savings, see Efficient Windows Collaborative. Resources Whole Building Design Guide - Passive Solar Heating Introduction http://www.wbdg.org/resources/psheating.php Solar Energy Basics (NREL) http://www.nrel.gov/learning/re_solar.html
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Fosdick, Judy. WBDG. “Passive Solar Heating.” June 17, 2010. http://www.wbdg.org/resources/psheating.php (accessed July 30, 2010). 7 Drumheller, S. Craig. ASRAE and DOE | EERE. “Final Evaluation of Low-E Storm Windows.” 2007. http://www1.eere.energy.gov/buildings/windowsvolumepurchase/pdfs/low-e_storm_window_field_test.pdf
NJ GREEN BUILDING MANUAL
NEW COMMERCIAL UPDATED 5-MAY-11
Pacific Northwest National Laboratory (PNL) Energy Savings Estimator http://www.windowsvolumepurchase.org/R-5_Benefits_tool.xls US DOE Windows Volume Purchase Program http://www.windowsvolumepurchase.org/ Sustainable Sources- Understanding Passive Systems: batch and thermosiphon http://solarheatcool.sustainablesources.com/#PASSIVEDHW Technology Fact Sheet: Passive Solar Design (NREL) http://search.nrel.gov/cs.html?url=http%3A//apps1.eere.energy.gov/buildings/publications/pdfs/b uilding_america/29236.pdf&charset=utf-8&qt=passive+solar+design&col=eren&n=2&la=en NJ’s Clean Energy Program http://www.njcleanenergy.com/ NJ Clean Energy Program Solar Energy Incentives http://www.njcleanenergy.com/renewable-energy/technologies/solar/costs-incentives-andsavings/costs-incentives-and-savings