Design And Fabrication of a Solar Hand Washing Cistern Using An Integrated Solar Collector

Abstract

This study examines the problem of providing small volume, hot water, for purposes of sanitation in Kenyan informal food establishments. It explores the effectiveness of small batch heaters, also known as integrated collector storage solar water heaters (ICSSWH), for this purpose. Locally available materials were used for the fabrication. The comparison of the thermal efficiency at different orientations of the cistern relative to the suns path across the sky was evaluated. Also examined was the effect of tilt angle on thermal efficiency and on the uniformity of temperatures throughout the load. Performance of the collector with no cover, with a glass cover and with a plastic cover was analyzed, as well as the performance of the absorber with a finned absorber versus a plain absorber. The results of this indicatesis that the device can be used to substitute the charcoal cisterns. It delivers hot water at a suitable temperature for hand washing and at a low cost(it is long lasting, portable, and easy to use and requires no plumbing to cold water sources in order to push out the heated water). The best angle of inclination for optimum operation was found to be between 45⁰ to 60⁰. The cistern worked best with a finned other than a plain absorber. The study results indicated that adding baffles to the underside of the collector aided in proper mixing of water to reduce the vertical temperature stratification. This occurred as a result of induced thermal currents which provided a mixing action of the water across the vertical layers in the collector tank.