Energy performance assessment of a novel enhanced solar thermal system with topology optimized latent heat thermal energy storage unit for domestic water heating

Abstract

In this study, we introduce an innovative approach by incorporating a Topology-Optimized Latent Heat Thermal Energy Storage (TO-LHTES) unit with fins into a solar water heating system. Employing EnergyPlus software, we initially assess the energy and power requirements essential for meeting domestic hot water needs within the Moroccan context. Afterward, Computational Fluid Dynamics (CFD) analyses explore diverse Phase Change Materials (RT35, RT50, and RT60) under varying operational conditions, including injected temperature, velocity, and stored temperature. Our investigation extends to different climates, evaluating the energy savings potential. The study's outcomes reveal the remarkable efficacy of the enhanced solar system featuring the TO-LHTES unit, particularly with specific configurations—such as an injected temperature of 20 °C, injected velocity of 0.02 m/s, stored temperature of 80 °C, and RT50 as the chosen Phase change material. Given the poor thermal conductivity of many PCMs, effective heat distribution and storage necessitate innovative methods. While various finned heat exchanger structures have been explored in existing literature, a notable gap exists in non-intuitive heat exchanger concepts specifically tailored for LHTES units. This work contributes by presenting an innovative TO-LHTES unit design, advancing the understanding and applicability of latent heat storage in solar water heating systems. Importantly, a maximum energy savings of 63.2% was achieved.