Solar thermal energy storage for heating applications — A review

Rise in energy demands and the need to curb carbon emissions has made proliferation of conventional fuels unviable, leading towards the search for alternative energy sources. With a surplus of sunlight reaching the earth every day, solar energy is an immediate renewable alternative to be considered for satisfying the end-user demand requirements. However, generation using solar energy poses its own challenges such as low energy density, fluctuations in energy generation, and mismatch in supply-demand, making it impracticable. In this paper, recent developments in solar thermal and solar photovoltaic systems utilizing thermal energy storage (TES) for heating applications have been reviewed and presented. A general trend in improvements in performance and efficiencies of the solar thermal systems were observed by integrating them with the TES modules. Furthermore, it is suggested that, research in terms of materials suitable for solar thermal storage and design of thermal storage systems is necessary in achieving cost efficient solar-TES systems with enhanced performance for a variety of heating applications.