Technical, economic and environmental evaluation of a distributed photovoltaic-battery system for residential buildings with phase change materials

Integrating energy storage systems is crucial for achieving temporal and dimensional energy balance, and maintaining the stability of grid-connected distributed photovoltaic (PV) systems for buildings. This study proposed a coupling system composed of distributed PV, battery, and phase change materials (PCM) for residential buildings. PCM was incorporated into building walls to reduce heating, cooling and associated carbon emissions. A dynamic battery operation strategy was developed to enhance system independence. The technical, economic and environmental performance of the system was evaluated by comparing the scenarios with and without PCM incorporation and battery optimization strategy. A dynamic carbon emission factor was also proposed to examine the impacts of PV generation. Results showed that incorporating PCM led to an average power demand reduction of 5.2 %. The optimized battery operation strategy led to a 23.2 % increase in both PV self-sufficiency and self-consumption, along with a reduction of 18.4 % and 31.4 % in the energy sent to and consumed from the grid, respectively. The optimized strategy resulted in an increase in the payback period by 1.72 years, while annual carbon emissions were reduced by 162.4 kgCO2. The annual average carbon emission factor decreased by 36.3 % compared to the grid emission factor.