SciTech Connect

Title: Energy Saving Potentials and Air Quality Benefits of Urban HeatIslandMitigation

Energy Saving Potentials and Air Quality Benefits of Urban HeatIslandMitigation Urban areas tend to have higher air temperatures than their rural surroundings as a result of gradual surface modifications that include replacing the natural vegetation with buildings and roads. The term ''Urban Heat Island'' describes this phenomenon. The surfaces of buildings and pavements absorb solar radiation and become extremely hot, which in turn warm the surrounding air. Cities that have been ''paved over'' do not receive the benefit of the natural cooling effect of vegetation. As the air temperature rises, so does the demand for air-conditioning (a/c). This leads to higher emissions from power plants, as well as increased smog formation as a result of warmer temperatures. In the United States, we have found that this increase in air temperature is responsible for 5-10% of urban peak electric demand for a/c use, and as much as 20% of population-weighted smog concentrations in urban areas. Simple ways to cool the cities are the use of reflective surfaces (rooftops and pavements) and planting of urban vegetation. On a large scale, the evapotranspiration from vegetation and increased reflection of incoming solar radiation by reflective surfaces will cool a community a few degrees in the summer. As an example, computer simulations for Los Angeles, more » CA show that resurfacing about two-third of the pavements and rooftops with reflective surfaces and planting three trees per house can cool down LA by an average of 2-3K. This reduction in air temperature will reduce urban smog exposure in the LA basin by roughly the same amount as removing the basin entire onroad vehicle exhaust. Heat island mitigation is an effective air pollution control strategy, more than paying for itself in cooling energy cost savings. We estimate that the cooling energy savings in U.S. from cool surfaces and shade trees, when fully implemented, is about $5 billion per year (about $100 per air-conditioned house). « less
Authors:
Publication Date:
OSTI Identifier:860475
Report Number(s):LBNL--58285
R&D Project: EK241L; BnR: 600303000; TRN: US200524%%204
DOE Contract Number:DE-AC02-05CH11231
Resource Type:Conference
Data Type:
Resource Relation:Conference: First International Conference on Passive and LowEnergy Cooling for the Built Environment, Athens, Greece, May 17-24,2005
Research Org:Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org:USDOE. Assistant Secretary for Energy Efficiency andRenewable Energy. Office of the Deputy Assistant Secretary for TechnologyDevelopment. Office of the Building Technologies Program; CaliforniaEnergy Commission
Country of Publication:United States
Language:English
Subject: 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; AIR CONDITIONING; AIR POLLUTION CONTROL; AIR QUALITY; COMPUTERIZED SIMULATION; ENERGY ACCOUNTING; MITIGATION; MODIFICATIONS; PAVEMENTS; PLANTS; POWER PLANTS; REFLECTION; SMOG; SOLAR RADIATION; TREES; URBAN AREAS