CFD modeling of a thermal energy storage based heat pipe evacuated tube solar collector

The increase in greenhouse gases makes it necessary to utilize renewable energy sources such as solar energy. The most important component of any solar system is solar collector. Among various types of solar collectors, evacuated tube solar collector (ETC) has attracted many attentions especially for the application in solar water heating systems (SWHs). However, due to the intermittency in solar intensity, the ETCs may not work at their maximum functionality. In this study, the computational fluid dynamics (CFD) modeling of a heat pipe ETC (HPETC) with and without the integration of phase change materials (PCMs) is performed. In order to cross-validate the obtained results from CFD and recent experimental analysis, the boundary conditions are set as the field-testing data. In phase-I, the 3D model of commercially available HPETC is simulated, while in phase-II, the HPETC integrated with the PCM is developed. The selected type of PCM is Tritriacontane paraffin (C33H68) with melting point of 72 degrees C. The simulation results show an acceptable agreement with the experimental data with an average deviation of 4.80% and 2.04% for phase-I and phase-II, respectively. The result from this study can be a benchmark for further optimization of HPETCs in thermal energy storage systems.