Study of sunflower oil for heat transfer and storage applications

Abstract

Heat transfer fluids are essential for heat collection in solar thermal collectors. Using heat transfer and storage materials can effectively increase the viability of thermal collectors. In the present study, the thermal performance of sunflower oil for heat transfer and storage is investigated and compared with water. Three experiments, auxiliary charging, simultaneous charging, and discharging, were conducted using an experimental setup for two combinations of three heat storage tanks. The characteristic parameters, thermal efficiency, fluid heating/charging, and cooling/discharging rates, are determined. In auxiliary charging, the efficiency of heat storage tank-1 was the same at 30.2 % for water and investigated oil. In the case of simultaneous charging for heat storage tank-2, it was found to be higher, 12.4 % for sunflower oil, than 9.9 % for water. The natural discharging rate of heat storage tank-3 was higher at 0.462 °C/min for sunflower oil than 0.292 °C/min for water. The charging rate of heat storage tank-2 through a heat exchanger is 6.96 °C/min for both fluids. The specific heat capacity of the investigated oil is lower than water, which limits its heat storage capacity. However, this limitation is overcome due to its high boiling temperature, making it a better heat transfer fluid than water.