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In passive solar building design, windows, walls, and floors are made to collect, store, reflect, and distribute solar energy, in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design because, unlike active solar heating systems, it does not involve the use of mechanical and electrical devices.
In the study of heat transfer, radiative cooling is the process by which a body loses heat by thermal radiation. As Planck's law describes, every physical body spontaneously and continuously emits electromagnetic radiation.
A green roof or living roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems. Container gardens on roofs, where plants are maintained in pots, are not generally considered to be true green roofs, although this is debated. Rooftop ponds are another form of green roofs which are used to treat greywater. Vegetation, soil, drainage layer, roof barrier and irrigation system constitute the green roof.
A radiant barrier is a type of building material that reflects thermal radiation and reduces heat transfer. Because thermal energy is also transferred by conduction and convection, in addition to radiation, radiant barriers are often supplemented with thermal insulation that slows down heat transfer by conduction or convection.
The emissivity of the surface of a material is its effectiveness in emitting energy as thermal radiation. Thermal radiation is electromagnetic radiation that most commonly includes both visible radiation (light) and infrared radiation, which is not visible to human eyes. A portion of the thermal radiation from very hot objects is easily visible to the eye.
A flat roof is a roof which is almost level in contrast to the many types of sloped roofs. The slope of a roof is properly known as its pitch and flat roofs have up to approximately 10°. Flat roofs are an ancient form mostly used in arid climates and allow the roof space to be used as a living space or a living roof. Flat roofs, or "low-slope" roofs, are also commonly found on commercial buildings throughout the world. The U.S.-based National Roofing Contractors Association defines a low-slope roof as having a slope of 3 in 12 (1:4) or less.
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Reflective surfaces, or ground-based albedo modification (GBAM), is a solar radiation management method of enhancing Earth's albedo. The IPCC described this method as "whitening roofs, changes in land use management, change of albedo at a larger scale ."
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Cool pavement is defined by the United States Environmental Protection Agency as pavement that implements technologies contributing to heat island effect reduction efforts. Most cool pavements either increase pavement albedo to reflect shortwave radiation out of the atmosphere and reduce heat transfer to the Earth’s surface, or use evaporative water cooling through the pavement to lower ambient temperatures. Newer technologies involve energy harvesting, heat storage methods, and phase change materials. Cool pavements are commonly made with reflective coatings or aggregates applied to conventional pavements or incorporation of porous or permeable materials. While pavement load capability may be reduced with more frequent maintenance requirements, cool pavements show promising results in reducing ambient temperatures and reducing energy usage.
Passive daytime radiative cooling (PDRC) is the use of unpowered, reflective/thermally-emissive surfaces to lower the temperature of a building or other object.
References
- ↑ Akabari, Hashem (June 1979). Optimal size and location of nuclear power plants in energy parks (PhD thesis). Univ. of California, Berkeley.
- ↑ California, Federal Naturalization Records, 1843-1999
- ↑ Akbari H. Advances in developing standards for accelerated aging of cool roofing materials. Roof coatings manufacturers association international roof coatings conference, Baltimore, Maryland, United States, July 14–17, 2014.
- ↑ Levinson, Ronnen; Akbari, Hashem; Konopacki, Steve; Bretz, Sarah (15 December 2002). Inclusion of cool roofs in nonresidential Title 24 prescriptive requirements (Report). Vol. 33. Office of Scientific and Technical Information (OSTI). pp. 151–170.
- ↑ Synnefa, A.; Santamouris, M.; Akbari, H. (2007). "Estimating the effect of using cool coatings on energy loads and thermal comfort in residential buildings in various climatic conditions". Energy and Buildings. 39 (11): 1167–1174. doi:10.1016/j.enbuild.2007.01.004. ISSN 0378-7788.
- ↑ Bretz, Sarah; Akbari, Hashem; Rosenfeld, Arthur (1998). "Practical issues for using solar-reflective materials to mitigate urban heat islands". Atmospheric Environment. 32 (1): 95–101. doi:10.1016/s1352-2310(97)00182-9. ISSN 1352-2310.
- ↑ "95/06565 Mitigation of urban heat islands: Materials, utility programs, updates". Fuel and Energy Abstracts. 36 (6): 464. 1995. doi:10.1016/0140-6701(95)98137-g. ISSN 0140-6701.
- ↑ Akbari, Hashem; Taha, Haider (1992). "The impact of trees and white surfaces on residential heating and cooling energy use in four Canadian cities". Energy. 17 (2): 141–149. doi:10.1016/0360-5442(92)90063-6. ISSN 0360-5442.
- ↑ "Background: Hashem Akbari - 2004 World Technology Awards Winners & Finalists". www.wtn.net. The World Technology Network. Archived from the original on 27 May 2019. Retrieved 27 May 2019.
- ↑ Akbari H, Konopacki S, Parker D, et al. Updates on revision to ASHRAE Standard 90.2: Including roof reflectivity for residential buildings[J]. American Council for an Energy Efficient Economy. ACEEE Summer Study on Energy Efficiency in Buildings. Pacific Grove, CA, 2000.
- ↑ ASHRAE A S. Standard 90.1-2004, Energy standard for buildings except low rise residential buildings[J]. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc, 2004.
- ↑ Akbari, H., Konopacki, S.J., Lister, L.D., DeBaillie, L.P. Energy End-Use Characterisation at Fort Hood, Texas. ASHRAE / 1996.
- ↑ Konopacki, S.J., Akbari, H., Lister, L.D. et al. Electrical Energy and Cost Savings Potential at DOD Facilities. ASHRAE / 1996.
- ↑ Akbari, H.; Davis, S.; Huang, J.; Dorsano, S.; Winnett, S. (1 January 1992). Cooling our communities: A guidebook on tree planting and light-colored surfacing (Report). Washington, D.C: Office of Scientific and Technical Information (OSTI). Also Report No. LBL-31587.
