Configuration Optimization And Performance Analysis Of Multi-energy Combined Cooling,Heating And Power (CCHP) System

Being a typical distributed energy system,the combined cooling,heating and power(CCHP)system is energy-saving,environmentally friendly and flexible compared with the separation production(SP)system.In this paper,a multi-energy CCHP system which couples wind power generation,photovoltaic power generation and natural gas CCHP system is proposed.Its configuration optimization problem is studied.Hourly electric and thermal energy balance equations for multi-energy and natural gas CCHP systems are proposed.Energy conversion models of the equipment in the CCHP systems are established.The evaluation criteria include primary fossil energy saving rate(PFESR),carbon dioxide emission reduction rate(CDERR)and annual total cost saving rate(ATCSR)compared with the separation production(SP)system.The particle swarm optimization(PSO)is used to calculate the optimal equipment capacity as well as PFESR,CDERR and ATCSR of multi-energy and natural gas CCHP systems for a hypothetical commercial building in Shanghai.Results show that the multi-energy CCHP system reaches higher PFESR and CDERR compared with the natural gas system.However,due to the high investment cost of wind power and photovoltaic power generation systems,the economic performance of the multi-energy system is worse than that of the natural gas system,and it is even worse than that of the SP system under following the thermal load(FTL)operation strategy.Sensitivity analysis of natural gas price as well as pool purchase price for electricity generated by natural gas generating set and by renewable energy is performed.Besides,hybrid cooling CCHP systems,including system coupling with electric chiller,with gas-fired chiller(GFC)and with ground source heat pump(GSHP),are studied.Results show that hybrid cooling can improve the comprehensive performance of multi-energy CCHP system.System coupling with GSHP has the best comprehensive performance as well as PFESR and CDERR,while system coupling with GFC has the best ATCSR.