摘要
1.INTRODUCTION Buildings and building related activities represent one of the largest energy consuming sectors in the United States.In Illinois,from 1950 to 1990 a population increase of approximately 2.7 million translated into dramatic natural resource consumption increases.For example,Illinois residents currently require almost 30 million gallons of petroleum per day.According to the U.S.Department of Energy,annual energy expenditures in the State have now reached over$34 billion with commercial buildings consuming over$5.6 billion alone.This represents an increase of over$14 billion since 1980.Overall energy consumption in Illinois amounts to 3.96 quadrillion BTUs,nearly two-thirds of which can be attributed to buildings and building related consumers.
