Optimization of a thermal storage tank for a water-water heat pump solar assisted

Thermal energy storage plays a key role in renewable resource management by finding a balance between random renewable energy production and building energy demand. This work investigates the role of thermal energy storage in a system consisting of a water source heat pump, and hybrid photovoltaic thermal panels (PVT), connected by the thermal storage tank for heating a residential building. Using a mathematical model built in Simulink, the fraction of thermal energy produced by the PVT and stored in the buffer tank and the fraction related to the coverage of the load by the renewable resource was evaluated as a function of the volume of the buffer tank and of the set-temperature point to the cold sink of the heat pump. The results show that for each degree less required at the cold source of HP there is an average annual increase of the before-mentioned fractions of 6.0%. By quadrupling the volume of thermal storage, the fraction of thermal energy accumulated increases by 73%, and the fraction of load coverage by renewable energy increases by 30%.