Optimization of a solar assisted heat pump system to increase thermal efficiency working on the cold source

This study introduces an innovative high-efficiency air conditioning system that utilizes solar-assisted heat pumps to enhance the coefficient of performance by elevating the thermal level of the lower temperature heat source. Solar energy stored in thermal storage is used to optimize operating conditions by increasing the cold source temperature. A demonstrator of such a system is investigated by referring to the residential building “Chiodo 2” located at the University of Calabria, where an existing plant equipped with heat pumps in master-slave configuration are already operational. The simulation model was developed within the TRNSYS environment. The development process of the virtual system model is presented in detail, encompassing solar collectors, thermal storage, heat pump and a photovoltaic system. Through an analysis of the winter operation of the system, the study identifies key requirements, including the optimal thermal storage volume and the optimal size of solar collectors, to maximize energy efficiency. Specific operating conditions are proposed, such as the synergistic use of solar collectors and heat pump in particular thermal scenarios, to enhance performance.