Multi-criteria optimization of a biomass gasification-based combined cooling, heating, and power system integrated with an organic Rankine cycle in different climate zones in China

Abstract

In this work, a multi-criteria optimization on a biomass gasification-based combined cooling, heating, and power system integrated with an organic Rankine cycle (ORC) is conducted. The ORC module is driven by the waste heat of the power generation unit. The criteria for the optimization comprise primary energy saving ratio (PESR), total cost saving ratio (TCSR), and CO2 reduction saving ratio (CERR). A criterion based on Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) is employed as the evaluation basis of the multi-criteria optimization. The improvement caused by ORC integration and multi-criteria optimization is investigated by comparing with the systems without the former and/or the latter one. Through case studies of a hypothetical hotel building located in six different climate zones in China, it is found that after the integration of an ORC module and multi-criteria optimization, the annual PESR, TCSR, and CERR are varied from 4.8%/−2.2%/7.0% to 8.4%/ 3.5%/12.0%, respectively, in different climate zones. The parameters of biomass and grid electricity, which are both location-related, have decisive effect on the system performance and the optimization results. Comparing with integration of an ORC module, the multi-criteria optimization has larger improvement of PESR when cooling demand is low, of TCSR when thermal demand is low, and of CERR in all the studied load conditions.