ABSTRACT
The thermal performance of a solar cooker with phase change thermal storage unit based on a parabolic trough collector was investigated. In this experimental setup, a one-ended open vacuum tube was used as receiver, and solar radiations were focused on it. The available solar heat at the receiver was transferred to the solar cooker by natural circulation (thermosiphon) of the heat transfer fluid. Water and thermal oil (engine oil) were used separately as heat transfer fluids. Commercial-grade acetanilide was used as latent heat storage material in the solar cooker. In daytime, the transfer of solar heat was a twofold process: 1) the solar heat from the receiver tube was transferred to an intermediate latent heat storage unit and 2) the energy was subsequently transferred from the storage unit to the cooking vessel. During evening hours this stored energy was used to cook food. The cooking process was carried out with different types and quantities of food. It was observed that for different cases the maximum temperature of thermal oil was 5.8–22.1°C higher than when water was used as heat transfer fluid. Using thermal oil as heat transfer fluid, the quantity of heat stored by phase change materials (PCMs) was increased by 26.66–67.49% as compared to when water was used as heat transfer fluid.
