An off-design model to optimize CCHP-GSHP system considering carbon tax

Abstract To closely reflect the actual working condition of CCHP-GSHP system, the aim of this study is to propose an off-design optimization model of the CCHP-GSHP coupled system considering carbon tax. In the optimal model, there are 13 decision variables containing rated capacity of power generation unit (1 decision variable) and the system monthly energy ratios (12 decision variables); energy criteria, environment criteria and economy criteria (considering carbon tax) are combined together as optimization objective. A hybrid particle swarm optimization is used to solve the model. A case study is realized to demonstrate the optimization model. The results of this study show that the CCHP-GSHP system has better performance compared with the reference system (annual energy consumption saving ratio is 31.79%; annual carbon dioxide emission reduction ratio is 51.34%; annual total cost reduction ratio is 25.64%; optimization objective is 36.26%). The sensitivity analysis of the electricity and natural gas price is taken into consideration in the end.