Strategically placed trees can modify urban temperatures by casting shade and thus affect energy consumption for residential cooling and heating. Energy conservation benefits are influenced by the quantity as well as the quality of tree shade upon building surfaces. In this study, we employed an energy simulation program called EnergyPlus as a means to evaluate the effect of a single shade tree upon a structure model having a floor area of 200 m2 in four U.S. cities. Results of EnergyPlus simulations with various single tree planting configurations showed that a large tree on the west aspect of a structure could decrease annual energy costs by up to 160 kWh (valued at $18) in southern cities with longer cooling seasons. Whereas, the same tree on the south aspect could increase annual energy costs by up to 134 kWh (−$15) in northern cities with longer heating seasons. In addition to tree placement around the structure, interactions between sun angle, tree form, and tree distance were observed to influence the effects on energy consumption. Understanding the fundamental interactions between tree form, tree placement, and geographic settings, which influence both the quantity and quality of shade provision, is critical for improving energy conservation benefits of trees in urban settings.
Hwang, Won Hoi; Wiseman, P. Eric; and Thomas, Valerie A.
"Simulation of Shade Tree Effects on Residential Energy Consumption in Four U.S. Cities,"
Cities and the Environment (CATE):
1, Article 2.
Available at: http://digitalcommons.lmu.edu/cate/vol9/iss1/2