Hashem Akbari

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Hashem Akbari
هاشم اکبری
Born(1949-08-13)13 August 1949
Iran
NationalityIranian

Hashem Akbari (born 13 August 1949) is an Iranian-American professor of Building, Civil and Environmental Engineering at Concordia University. He specializes in research on the effects of urban heat islands, cool roofs, paving materials, energy efficiency, and advanced integrated energy optimization in buildings.

Contents

Biography

Akbari was born in Iran. He received his Ph.D. of Nuclear Engineering at University of California, Berkeley in 1979. [1] He became a U.S. citizen in 1991. [2] In 2009, he joined the Concordia University, where he founded a comprehensive laboratory to measure solar spectral reflectance and thermal emittance of common construction materials. Prior to joining the Concordia University, he was a senior scientist and the leader of the Heat Island Group at Environmental Energy Technologies Division of Lawrence Berkeley National Laboratory (LBNL) at the University of California (from 1983 to 2009). In 1985, he founded the Urban Heat Island (UHI) group, where he worked in the areas of heat-island quantification, mitigation and novel techniques in the analysis of energy use in buildings and industry in the United States and abroad.

Research

Akbari conducted ground-breaking research on the potential for cool roofing and paving materials to reduce the urban heat islands effect. [3] His proposed work in adapting cool roofs as a "prescriptive" requirement for low-slope non-residential buildings in California. [4] In 2003, his proposal was approved by the California Energy Commission, and it went into effect later in October 2005. He provided basis and assistance for the development of cool roofs standards in Florida, Chicago, Georgia, and Atlanta.

His research has quantified the effect of cool roofs (increasing surface albedo) on cooling the globe. [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] As a result of his research, the heat-island mitigation program has been expanding in other countries; for example, the city of Osaka, Japan has recently instituted a $1.7 B (170 B Yen) program of cool roofs, green roofs, and urban trees. [16]

Akbari's contribution to the development of several international standards are:

In addition to the standards development, Akbari was the author of Intergovernmental Panel for Climate Change (2007 Nobel Peace Prize). He also contributed in writing of two chapters for ASHRAE Application Handbook: (1) Building Energy Monitoring and (2) Energy Use and Management. [19] [20] He published a guidebook for urban heat island mitigation. [21]

Akbari is one of the founding organizers of the Global Cool Cities Alliance (vice Chairman of the Board, Technical committee chair), the Cool Roof Rating Council (CRRC) (Ex-Officio Board Member, International Committee Chair), and the European Cool Roof Council (ECPR) (Ex-Officio Board Member).

Related Research Articles

<span class="mw-page-title-main">Albedo</span> Ratio of how much light is reflected back from a body

Albedo is the fraction of sunlight that is diffusely reflected by a body. It is measured on a scale from 0 to 1.

<span class="mw-page-title-main">Roof</span> Top covering of a building

A roof is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of temperature, and wind. A roof is part of the building envelope.

<span class="mw-page-title-main">Urban heat island</span> Urban area that is significantly warmer than its surrounding rural areas

An urban heat island (UHI) is an urban area that is significantly warmer than its surrounding rural areas due to human activities. The temperature difference is usually larger at night than during the day, and is most apparent when winds are weak. UHI is most noticeable during the summer and winter. The main cause of the UHI effect is from the modification of land surfaces. A study has shown that heat islands can be affected by proximity to different types of land cover, so that proximity to barren land causes urban land to become hotter and proximity to vegetation makes it cooler. Waste heat generated by energy usage is a secondary contributor. As a population center grows, it tends to expand its area and increase its average temperature. The term heat island is also used; the term can be used to refer to any area that is relatively hotter than the surrounding, but generally refers to human-disturbed areas.

<span class="mw-page-title-main">Radiative cooling</span> Loss of heat by thermal radiation

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.

<span class="mw-page-title-main">Green roof</span> Roof that is covered with vegetation and a growing substrate

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 green roof.

<span class="mw-page-title-main">Radiant barrier</span>

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.

Climate engineering is a term used for both carbon dioxide removal and solar radiation management, also called solar geoengineering, when applied at a planetary scale. However, they have very different geophysical characteristics which is why the Intergovernmental Panel on Climate Change no longer uses this overarching term. Carbon dioxide removal approaches are part of climate change mitigation. Solar geoengineering involves reflecting some sunlight back to space. All forms of geoengineering are not a standalone solution to climate change, but need to be coupled with other forms of climate change mitigation. Another approach to geoengineering is to increase the Earth's thermal emittance through passive radiative cooling.

<span class="mw-page-title-main">Flat roof</span> Type of roof

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.

The climate in urban areas differs from that in neighboring rural areas, as a result of urban development. Urbanization greatly changes the form of the landscape, and also produces changes in an area's air. The study of urban climate is urban climatology.

<span class="mw-page-title-main">Sustainable architecture</span> Architecture designed to minimize environmental impact

Sustainable architecture is architecture that seeks to minimize the negative environmental impact of buildings through improved efficiency and moderation in the use of materials, energy, development space and the ecosystem at large. Sustainable architecture uses a conscious approach to energy and ecological conservation in the design of the built environment.

<span class="mw-page-title-main">Reflective surfaces (climate engineering)</span>

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 ."

<span class="mw-page-title-main">Underfloor heating</span> Form of central heating and cooling

Underfloor heating and cooling is a form of central heating and cooling that achieves indoor climate control for thermal comfort using hydronic or electrical heating elements embedded in a floor. Heating is achieved by conduction, radiation and convection. Use of underfloor heating dates back to the Neoglacial and Neolithic periods.

<span class="mw-page-title-main">Building insulation</span> Material to reduce heat transfer in structures

Building insulation is material used in a building to reduce the flow of thermal energy. While the majority of insulation in buildings is for thermal purposes, the term also applies to acoustic insulation, fire insulation, and impact insulation. Often an insulation material will be chosen for its ability to perform several of these functions at once.

<span class="mw-page-title-main">Solar gain</span> Solar energy effect

Solar gain is the increase in thermal energy of a space, object or structure as it absorbs incident solar radiation. The amount of solar gain a space experiences is a function of the total incident solar irradiance and of the ability of any intervening material to transmit or resist the radiation.

<span class="mw-page-title-main">Passive ventilation</span> Ventilation without use of mechanical systems

Passive ventilation is the process of supplying air to and removing air from an indoor space without using mechanical systems. It refers to the flow of external air to an indoor space as a result of pressure differences arising from natural forces.

Interior Radiation Control Coating Systems (IRCCS), sometimes referred to as radiant barrier coatings, are paints designed to provide thermal insulation to buildings.

Thermal emittance or thermal emissivity is the ratio of the radiant emittance of heat of a specific object or surface to that of a standard black body. Emissivity and emittivity are both dimensionless quantities given in the range of 0 to 1, representing the comparative/relative emittance with respect to a blackbody operating in similar conditions, but emissivity refers to a material property, while emittivity refers to specific samples or objects.

<span class="mw-page-title-main">Infrared and thermal testing</span>

Infrared and thermal testing refer to passive thermographic inspection techniques, a class of nondestructive testing designated by the American Society for Nondestructive Testing (ASNT). Infrared thermography is the science of measuring and mapping surface temperatures.

"Infrared thermography, a nondestructive, remote sensing technique, has proved to be an effective, convenient, and economical method of testing concrete. It can detect internal voids, delaminations, and cracks in concrete structures such as bridge decks, highway pavements, garage floors, parking lot pavements, and building walls. As a testing technique, some of its most important qualities are that (1) it is accurate; (2) it is repeatable; (3) it need not inconvenience the public; and (4) it is economical."

<span class="mw-page-title-main">Cool pavement</span> Reflective road surface

Cool pavement is a road surface that uses additives to reflect solar radiation unlike conventional dark pavement. Conventional dark pavements contribute to urban heat islands as they absorb 80–95% of sunlight and warm the local air. Cool pavements are made with different materials to increase albedo, thereby reflecting shortwave radiation out of the atmosphere. Increasing albedo reduces heat transfer to the surface and can hypothetically cause local cooling if the spatial scale of the albedo reduction is sufficiently large. The EPA reports "that if pavement reflectance throughout a city were increased from 10 to 35 percent, the air temperature could potentially be reduced by 1°F (0.6°C)." Existing dark pavement can be altered to increase albedo through whitetopping or by adding reflective coats and seals. New pavement can be constructed to increase albedo by using modified mixes, permeable pavements, and vegetated pavements.

<span class="mw-page-title-main">Passive daytime radiative cooling</span> Management strategy for global warming

Passive daytime radiative cooling (PDRC) is a renewable cooling method proposed as a solution to global warming of enhancing terrestrial heat flow to outer space through the installation of thermally-emissive surfaces on Earth that require zero energy consumption or pollution. Because all materials in nature absorb more heat during the day than at night, PDRC surfaces are designed to be high in solar reflectance and strong in longwave infrared (LWIR) thermal radiation heat transfer through the atmosphere's infrared window (8–13 µm) to cool temperatures during the daytime. It is also referred to as passive radiative cooling (PRC), daytime passive radiative cooling (DPRC), radiative sky cooling (RSC), photonic radiative cooling, and terrestrial radiative cooling. PDRC differs from solar radiation management because it increases radiative heat emission rather than merely reflecting the absorption of solar radiation.

References

  1. ↑ Akabari, Hashem (June 1979). Optimal size and location of nuclear power plants in energy parks (PhD thesis). Univ. of California, Berkeley.
  2. ↑ California, Federal Naturalization Records, 1843-1999
  3. ↑ Akbari H. Advances in developing standards for accelerated aging of cool roofing materials. Roof coatings manufacturers association international roof coatings conference, Baltimore, Maryland, USA, July 14–17, 2014.
  4. ↑ Levinson R, Akbari H, Konopacki S, et al. Inclusion of cool roofs in nonresidential Title 24 prescriptive requirements[J]. Energy Policy, 2005, 33(2): 151-170.
  5. ↑ Synnefa, A., M. Santamouris, and H. Akbari, "Estimating the effect of using cool coatings on energy loads and thermal comfort in residential buildings in various climatic conditions," Energy and Buildings, 2007, 39(11): 1167–1174.
  6. ↑ Levinson, R. P. Berdahl, H. Akbari, W. Miller, I. Joedicke, J. Reilly, Y. Suzuki, M. Vondran, "Methods of creating solar-reflective nonwhite surfaces and their application to residential roofing materials," Solar Energy Materials & Solar Cells, 91, 304–314, 2007.
  7. ↑ Levinson, R., P. Berdahl and H. Akbari, "Solar spectral optical properties of pigments, Part I: Model for deriving scattering and absorption coefficients from transmittance and reflectance measurements," Solar Energy Materials & Solar Cells, 89(4): 319-349, 2005.
  8. ↑ Akbari, H., M. Pomerantz, and H. Taha, "Cool surfaces and shade trees to reduce energy use and improve air quality in urban areas," Solar Energy, 70(3): 295-310, 2001.
  9. ↑ Akbari, H., S. Konopacki, and M. Pomerantz, "Cooling energy savings potential of reflective roofs for residential and commercial buildings in the United States," Energy, 24: 391-407, 1999.
  10. ↑ Bretz, S., H. Akbari, and A. Rosenfeld, "Practical Issues for Using Solar-Reflective Materials to Mitigate Urban Heat Islands," Atmospheric Environment, 32(1): 95-101, 1998.
  11. ↑ Bretz, S. and H. Akbari, "Long-term Performance of High-Albedo Roof Coatings for Energy Efficient Buildings," Energy and Buildings – Special Issue on Urban Heat Islands and Cool Communities, 25(2): 159-167, 1997.
  12. ↑ Taha, H., and H. Akbari, "Urban Climates and Heat Islands: Albedo, Evapotranspiration, and Anthropogenic Heat," Energy and Buildings – Special Issue on Urban Heat Islands and Cool Communities, 25(2): 99-103, 1997.
  13. ↑ Rosenfeld, A., H. Akbari, S. Bretz, B. L. Fishman, D. M. Kurn, D. Sailor, H. Taha, "Mitigation of urban heat islands: materials, utility programs, updates," Energy and Buildings, 22: 255-265, 1995.
  14. ↑ Akbari, H., S. Bretz, H. Taha, D. Kurn, and J. Hanford, "Peak Power and Cooling Energy Savings of High-albedo Roofs," Energy and Buildings – Special Issue on Urban Heat Islands and Cool Communities, 25(2): 117-126, 1997.
  15. ↑ Akbari, H. and H. Taha, "The Impact of Trees and White Surfaces on Residential Heating and Cooling Energy Use in Four Canadian Cities." Energy, 17(2): 141-149, 1991; Akbari, H., A. Rosenfeld, and H. Taha, "Summer Heat Islands, Urban Trees, and White Surfaces," ASHRAE Transactions, 96(1), 1990.
  16. ↑ "Background: Hashem Akbari - 2004 World Technology Awards Winners & Finalists". www.wtn.net. The World Technology Network. Archived from the original on 2019-05-27. Retrieved 2019-05-27.
  17. ↑ 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.
  18. ↑ 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.
  19. ↑ Akbari, H., Konopacki, S.J., Lister, L.D., DeBaillie, L.P. Energy End-Use Characterisation at Fort Hood, Texas. ASHRAE / 1996.
  20. ↑ Konopacki, S.J., Akbari, H., Lister, L.D. et al. Electrical Energy and Cost Savings Potential at DOD Facilities. ASHRAE / 1996.
  21. ↑ Akbari, H., S. Davis, S. Dosano, J. Huang, and S. Winnett, (eds), Cooling Our Communities: A Guidebook on Tree Planting and Light-colored Surfacing, 1992, United States Environmental Protection, Agency, Washington, D.C. Also Report No. LBL-31587, Lawrence Berkeley National Laboratory, Berkeley, CA.
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