Study of a passive solar air heater using palm oil and paraffin as storage media

Abstract

This study evaluated a passive solar air heater using different storage media. The heater, which is very useful in low temperature applications like agricultural produce drying and heating of buildings, is made up of a double-glaze solar thermal collector of a flat plate type coupled with thermal storage medium. The heater was replicated using paraffin and palm oil as storage medium for systems ‘a’ and ‘b’ respectively. The evaluation of the systems without load under 24-h periods were carried out experimentally in Nsukka, Enugu State, Nigeria, within the weather temperature and daily radiation of 23.6–32.4 °C and 11.6–21.1 MJ m−2 respectively. The peak cumulative efficiencies were 57.3% for system ‘b’ and 46% for system ‘a’. Similarly, the mean efficiencies were 38.4% and 41.0% for systems ‘a’ and ‘b’ respectively. The results prove that for low temperature applications the systems can successfully be implored. From the study, it can be concluded that the use of palm oil as storage medium for solar air heaters is a good substitute for paraffin which is a non renewable medium with its future uncertainties due to depleting global crude oil reserves.