Enhancing the efficiency of solar water heaters with phase change materials: Numerical assessment

Solar water heaters are an efficient means of collecting solar energy; even though their efficacy diminishes with time owing to several reasons, including dust, cloud cover, and the sun's absence during daylight hours. Therefore, it is essential to employ additional methods to optimize system performance. In this study, the performance of solar water heater numerically investigated. A current geometrical design for a solar collector shaped like a heat exchanger is introduced. This study utilizes computational fluid dynamics (CFD) analysis to examine the effects of fins on the thermal efficiency of a solar water heater. Validation with previous study is conducted and the model meshing are tested. Turbulent k-ε, RNG model were used to solve the 3D model using ANSYS Fluent 2020 R1. Three configurations were examined: a fundamental model devoid of fins, a model including two fins, and a model incorporating four fins. In order to enhance the thermal storage through the clement condition, phase change material (PCMs) was embedded in the shell space. Through the normal operating conditions, PCM storing the thermal energy as a latent heat and release it back to the heating fluid through the absents of the sun. Sins the thermal conductivity is low, extended surfaces are utilized to shorten the melting period of PCM. The calculations indicated that using fins markedly enhances heat transport and storage efficiency. The findings show that the outlet water temperature reaches 51.4${}^{°}C$, 67.4${}^{°}C$, 67.5${}^{°}C$ for the conferential model, model A, model B, at 450 s respectively. Which indicated a 7.1 % and 7.3 % rise in output water temperature for models using two and four fins, respectively, compared to the standard design. Moreover, the fin-equipped models attained steady-state conditions more rapidly than the basic model, highlighting the efficiency of fins in expediting heat transfer through the PCM. The temperature distribution profiles demonstrated reduced thermal entry lengths in finned systems, corroborating improved performance. This study emphasizes the significance of fin design and phase change material integration in enhancing the thermal management of solar water heaters. The suggested design enhances energy storage and diminishes reliance on fossil fuels, supporting sustainable energy programs and highlighting the significance of advanced thermal technologies in renewable energy systems.