Optimization and performance comparison of combined cooling, heating and power/ground source heat pump/photovoltaic/solar thermal system under different load ratio for two operation strategies

Abstract Energy and environmental issues have led to increasing public concern about energy supply systems. The coupled system of clean fossil energy and renewable energy has become the main research direction. The optimization of system capacity and operation strategy is very important for a system to play its role. This paper mainly studies combined cooling, heating and power/ground source heat pump/photovoltaic/solar thermal coupled system. The optimization model is established for the following total thermal demand – load ratio and following total electric demand – load ratio operation strategy under different load ratio respectively from energy, economy and environment perspective. Multi-population genetic algorithm is used to solve the optimization model. A hotel building in Changsha is used to verify the optimization model. The equipment capacity of two operation strategies under different load ratio is given, and the heat and electricity distribution of two operation strategies under different load ratio are compared. Finally, the system performance of two operation strategies under different load ratio is given. The results show that the comprehensive performance of the coupled system in the following total electric demand – load ratio mode is better than that in the following total thermal demand – load ratio mode under different load ratio. The optimal load ratio is 0.2 for the following total thermal demand – load ratio operation strategy (annual primary energy saving ratio: 30.10%; annual total cost saving ratio: 26.58%; annual carbon dioxide emission reduction ratio: 43.31%; comprehensive performance: 33.33%) and 0.4 for the following total electric demand – load ratio operation strategy (annual primary energy saving ratio: 34.59%; annual total cost saving ratio: 31.59%; annual carbon dioxide emission reduction ratio: 52.37%; comprehensive performance: 39.52%).