Ecological life cycle analysis-based installation capacity determination of building energy-supply systems

Abstract

Based on the ecological life cycle analysis (Eco-LCA) theory, this study focused on constructing the ecological life cycle analysis framework and model of a combined cooling heating and power (CCHP) system equipped a gas internal combustion engine (GICE) in which the ecological cumulative exergy consumption (ECEC) is minimized to maximize ecological sustainability. This method solves the problem of low-efficiency operation resulting from the implementation of an unsuitable GICE installation capacity; additionally, the ecological view is first introduced into the stage of scheme decision to achieve the maximum ecological benefits. Moreover, a case study that involved implementing the GICE capacity design in a typical hospital building in Chongqing was performed to demonstrate the capability of the proposed model. The simulation results revealed that the operation-stage ECEC accounts for approximately 97% of the total ECEC for each design scheme. The 600-kW GICE installation capacity yielded the best ecological sustainability under the condition of satisfying the energy demand of the building; the ECEC of the CCHP system with a GICE was approximately 4.45E + 18 seJ, and the GICE equivalent full-load running time in one typical year is approximately 3289 h. In comparison to system of the case building, the installation capacity of GICE equipped according to the normal economic index is 400 kW. It shows that the optimal size of GICE is not always the same from economic and ecological perspectives, but the Eco-LCA can make more objective authentic decision due to without the arbitrary weighting of different ecological factors. Further, a simplified Eco-LCA of the CCHP system with GICE method is given out and it can provide reference for related engineering application.