Eco-friendly combined heating and cooling system integrated with solar photovoltaic and energy storage: Thermodynamic performance and carbon emission evaluation

To meet the energy-saving requirements of heating and cooling, a novel environmentally friendly combined heating and cooling system based on solar photovoltaic and energy storage technologies (PV-ES) is proposed. Thermodynamic and carbon emission models of the system, including power generation and life cycle carbon emission models, have been developed. Typical cities of different climate zones are selected as the application scenario for comparative analysis. The results display that maximum COP is obtained at the optimal discharge pressure. The maximum coefficient of performance (COP) of 7.347 is achieved at the discharge pressure of 8.13 MPa. The PV-ES system can reduce the discharge pressure compared with the baseline system (Base), which can be reduced by as high as 12.28 % at the ambient temperature of 40 °C. The total power consumption mainly reduces with the increasing of the latitude of the city, which can be reduced by 61.8–76.2 %. The carbon emissions roughly reduce with the increase in the latitude, decreasing by 51.3–63.3 % compared with the Base system. From the perspective of energy conversion efficiency and emission performance, the use of solar and energy storage technologies can considerably improve the comprehensive performance of environmentally friendly combined heating and cooling system.