Energy Savings of Heat-Island Reduction Strategies in Chicago and Houston (Including Updates for Baton Rouge, Sacramento, and Salt Lake City)

TitleEnergy Savings of Heat-Island Reduction Strategies in Chicago and Houston (Including Updates for Baton Rouge, Sacramento, and Salt Lake City)
Publication TypeJournal Article
Year of Publication2002
AuthorsSteven J Konopacki, Hashem Akbari

Initiative” to quantify the potential benefits of Heat-Island Reduction (HIR) strategies (i.e.,shade trees, reflective roofs, reflective pavements and urban vegetation) to reduce coolingenergyuse in buildings, lower the ambient air temperature and improve urban air quality incities, and reduce CO2 emissions from power plants. Under this initiative, the Urban Heat IslandPilot Project (UHIPP) was created with the objective of investigating the potential of HIR strategiesin residential and commercial buildings in three initial UHIPP cities: Baton Rouge, LA; Sacramento,CA; and Salt Lake City, UT. Later two other cities, Chicago, IL and Houston, TX wereadded to the UHIPP.In an earlier report we summarized our efforts to calculate the annual energy savings, peakpower avoidance, and annual CO2 reduction obtainable from the introduction of HIR strategies inthe initial three cities. This report summarizes the results of our study for Chicago and Houston.In this analysis, we focused on three building types that offer the highest potential savings:single-family residence, office and retail store. Each building type was characterized in detail byvintage and system type (i.e., old and new building constructions, and gas and electric heat). Weused the prototypical building characteristics developed earlier for each building type andsimulated the impact of HIR strategies on building cooling- and heating-energy use and peakpower demand using the DOE-2.1E model. Our simulations included the impact of (1)strategically-placed shade trees near buildings [direct effect], (2) use of high-albedo roofingmaterial on the building [direct effect], (3) urban reforestation with high-albedo pavements andbuilding surfaces [indirect effect] and (4) combined strategies 1, 2, and 3 [direct and indirecteffects]. We then estimated the total roof area of air-conditioned buildings in each city usingreadily obtainable data to calculate the metropolitan-wide impact of HIR strategies.The results show that in Chicago, potential annual energy savings of $30M could berealized by ratepayers from the combined direct and indirect effects of HIR strategies.Additionally, peak power avoidance is estimated at 400 MW and the reduction in annual carbonemissions at 58 ktC. In Houston, the potential annual energy savings are estimated at $82M, withan avoidance of 730 MW in peak power and a reduction in annual carbon emissions of 170 ktC.

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