Numerical and experimental investigation of the solar air heater with latent heat storage and fin

In current numerical work, a mathematical model for an air collector with latent heat storage is established and solved using the finite difference method. The glass, absorber plate, and air flow temperatures are described in one-dimensional unsteady terms. The storage material simulation is formed by a two-dimensional unsteady modeling and solved using the enthalpy method. By analyzing the temperature distribution and phase change behavior within the PCM using a two-dimensional unsteady model, this research provides a more detailed understanding of the thermal storage process compared to studies employing one-dimensional models. The mathematical model was validated by an outdoor experiment under prevailing climatic conditions in Ho Chi Minh City, Vietnam. The absorber plate is equipped with longitudinal rectangular fins to enhance heat transfer. Height of storage material, air flow rate and fin geometries are set as independent parameters to investigate phase change in latent storage and daily performance. Simulation results show that a storage height of 20 cm is suitable to fully liquify and to extend the operating time to 21:00. Attaching the fins increases the daily efficiency up to 13.7% compared to that of a smooth duct air collector. Latent heat storage provides the most uniform outlet air temperature compared to sensible storage and without storage. The standard deviation of outlet air temperature with time of day is 6.34 °C, 8.47 °C, and 9.20 °C for the types of latent heat storage, sensible heat storage, and without storage, respectively.