Long -Term Performance Estimation of Solar Water Still Based on Utilizability Function

Abstract

Performance of a basin solar water still such as production rate is studied in this research.It is observed that the measured production rates of the still do not vary linearly with hourly solar radiation incident on the basin. This is due to water heat capacity effect. The measured daily still productivity depends linearly on daily total solar radiation. The relation between the calculated daily still productivity based on Dunkle’s method and daily total solar radiation is also linear. Effecrs of ambient temperature and wind speed on still output strongly depend on solar radiation. So long-termperformance of the still can be easily calculated based on utilizability function. The function is developed from daily solar radiation. This performance is comparable to that of Dunkle’s of which monthly mean hourly solar radiation is input data.