Life-Cycle Impact Analysis of Energy Systems for Buildings

Abstract

Cogeneration systems offer an opportunity to satisfy a building’s electrical and thermal loads, which could result in an overall energy efficiency improvement and lower environmental impact. Hourly energy simulation and a life-cycle assessment framework are used to evaluate the relative environmental impacts and energy efficiencies of the construction and operation of alternative technologies for providing space and domestic water heating, cooling, and electrical power for equipment and lights in buildings. Life-cycle comparisons are presented for current practice (average U.S. power generation mix, electric chillers, and gas-fired boilers), high-efficiency natural gas combined-cycle power generation, and three building-integrated combined heat and power (CHP) technologies. The analysis demonstrates (1) a framework that supports decision making regarding system selection and operational strategies to limit environmental impact; (2) the importance of a life-cycle assessment framework, illustrated by the analysis of global warming potentials and tropospheric ozone potential; and (3) the importance of building load characteristics for the analysis of CHP scenarios.