Use of 1:7 rice bran wax to rice bran oil mixture as phase change material in increasing the efficiency of photovoltaic cells

CYRUS JEHU R. BARRERA, MANDY D. UMADHAY, JASPER C. CANSON, and ARIS C. LARRODER

Philippine Science High School – Western Visayas Campus, Brgy. Bito-on, Jaro, Iloilo City 5000, Department of Science and Technology, Philippines

Abstract

The efficiency of photovoltaic (PV) panels decreases as their operating temperature increases. To address this, phase-change materials (PCMs) are attached to the panel to absorb heat. PCMs are used to cool PV panels since they have the desired thermodynamic properties for heat storage such as high latent heat. The study focuses on determining the conversion efficiency of PV cells with rice bran wax in rice bran oil (RBW/RBO) mixture as PCM. Rice bran wax was added to rice bran oil in 1:7 by volume ratio. Three setups were compared in this study: PV cell without PCM, with paraffin wax, and with the RBW/RBO mixture. The paraffin wax was used because it is a commonly-used PCM for PV cells. The RBW/RBO mixture was used because it is a renewable resource and considered a waste product. The voltage and current of the PV cells were measured every 15 minutes for 45 minutes to compute the conversion efficiency. The RBW/RBO mixture increased the conversion efficiency of the PV cell by 0.232%. This may be attributed to its melting point being within the PV cell’s operating temperature. The RBW/RBO mixture can be used and improved to further increase the efficiency of PV cells for household use.

Keywords: phase change materials (PCM), photovoltaic cells, rice bran, solar energy, bio-based