Performance analysis of passive solar still with and without nanoparticles

Abstract

Solar still is a device that converts dirty water into freshwater. Low productivity is the drawback of solar still so it is not popular in the market. In the present paper, an attempt is made to improve the distilled output of solar still by mixing ZnO and CuO nanoparticles in the basin water and compared the performance of solar still with and without nanoparticles. An experimental setup having 41° tilt angle of the glass cover and 1 m2 basin area is fabricated and tested under winter climatic conditions of Gwalior city, India (Latitude: 26.2183° N, 78.1828° E). It is observed that solar still with CuO and ZnO nanofluids achieved 41.60% and 11.11% higher productivity respectively than the solar still without nanofluids. The convective, evaporative, and radiative heat transfer coefficient (HTC) from water to the glass surface and convective HTC from basin liner to water is also calculated for solar still with CuO and ZnO nanoparticles and solar still without nanoparticles. CuO has high thermal conductivity as compared to ZnO, hence the values of hc, he, and hr are found higher for still with CuO nanofluids. For solar still with CuO and ZnO nanofluids, the average value of evaporative (he,w-gi) and convective (hc,w-gi) HTC is found higher by 123.78% and 36.28%, 45.38%, and 15.24% respectively than the solar still without nanoparticles. Solar still with CuO gives 2025 ml/day distilled water, whereas ZnO and solar still without nanoparticles gives 1590 ml/day and 1430 ml/day distilled water respectively.