Optimal operation strategy of the hybrid heating system composed of centrifugal heat pumps and gas boilers

Centrifugal heat pump has to be coupled with gas boiler to supply high temperature water in radiator heating system. Regarding to hybrid heating system (HHS), operation strategy has significant impact on its annual energy consumption and cost. In this paper, the optimal operation strategy of the HHS composed of sewage-source centrifugal heat pumps and gas boilers was analyzed. Firstly, the performance models of the system components, including terminal radiator, heat pump, gas boiler and water pump were established respectively. Secondly, with the aim at minimizing the operating cost of the system the optimal operation strategy of the system was analyzed. Finally, the annual operating cost and energy consumption of the HHS were compared with these of coal-fired boiler heating system. The results indicate that the HHS offers significant reductions in energy consumption (45.2%) and operating cost (13.5%). Therefore, the HHS has a promising application prospect, the results provide reference for scientific operation of the HHS.

► Centrifugal sewage-source heat pumps are utilized in the radiator heating system.
► We establish calculation models of equipments utilized in a hybrid heating system.
► The optimal operation strategy is determined on the basis of minimum operating cost.
► Outlet water temperature of heating equipments at different outdoor temperatures was solved.
► Compared with coal-fired heating system, hybrid heating system has higher energy efficiency and better economic performance.