PERFORMANCE IMPROVEMENT OF CIRCULAR PARABOLIC CONCENTRATING SOLAR COOKER USING NANO-MIXED BINARY SALT PHASE CHANGE MATERIAL

Abstract

A multi-objective investigation has been carried out for a parabolic concentrator-type solar cooker with the use of nano-mixed binary salts phase change material (PCM) materials. Binary salts like NaNO<sub>3</sub> and KNO<sub>3</sub> are mixed with alumina (Al<sub>2</sub>O<sub>3</sub>) nanoparticles in the ratio of 0.5%, 1%, and 1.5% by weight. Properties such as thermal conductivity, specific heat, melting point, and thermal diffusivity are computed experimentally. Two food items, namely rice and dal, are selected for cooking purposes. The experimental results obtained from this research work show some promising returns. As compared to the plain PCM, the nano-mixed PCM reduces the cooking time, and with an increase in the addition of nanoparticles in PCM, the overall cooking time for both food items decreases. A difference of 5-6 minutes has been observed between plain PCM and nano-mixed PCM cooking. Another important observation made during this study is that the thermal properties of PCM material are affected by the addition of nanoparticles. The thermal conductivity increases by almost 10% and thermal diffusivity increases by 20%. The melting point of PCM decreases by 22°C, and the specific heat decreases by 12% and 17% at a temperature of 100°C and 250°C, respectively. Finally, it is concluded that the use of alumina nanoparticles in the binary salts PCM improves the thermal storage capacity of the PCM material.