Integration of Thermal Energy Storage and Photovoltaic Systems by Using Domestic Electric Water Heaters

Lately, the prices of photovoltaic (PV) technology, including modules and inverters, have significantly dropped, making it more economically feasible to use PV power for heating water in homes. Although thermal energy storage (TES) has the potential to balance energy supply and demand, it remains largely underexplored. TES solutions may have a key role in dealing with the adverse effects of the dynamically growing share of electricity generated by photovoltaic (PV) systems on electricity networks. This research explored the potential of implementing a novel technological approach in conjunction with PV usage in Austria and Hungary, aiming to encourage the adoption of economical energy storage solutions and lessen energy dependence. This study aimed to investigate the joint use of TES and PV systems in Austria and Hungary, specifically using a 3.5 kW quasi-sine inverter and an electric water heating appliance for households with a capacity of 200 liters, as examples. According to the results of the research, the tested 200-liter domestic electric water heating system can store an average of more than 16 kWh of heat energy per day during the summer months, with a maximum water temperature increase (ΔT) of up to 53 °C during this period. The research is innovative and practical, as it explores the application of this solution to assess the seasonal energy-saving potential of this method of sensible heat storage in the contexts of Austria and Hungary.