A Numerical Study for Estimation of the Solar Irradiance on Dome Shaped Solar Collectors/Stills

Abstract

Solar stills are considered as a cheaper solution for potable water production in develo** and underdeveloped nations. Numerous experimental studies have been done in this area to show that use of dome shaped or hemispherical solar still top cover gives better performance and distillate output. However, most of the investigations rely on experimentally developed empirical relations for different types of conventional flat plate solar still. These models come into use whilst accurately predicting the performance of a flat plate type solar still but not for dome shaped or hemispherical shaped collectors. In the present study, emphasis has been given to develo** an accurate model for estimation of the solar irradiance on dome shaped collectors/stills. Since the dome shape is not a conventional shape, the amount of radiation incident on the surface is different from flat surface. A comparative investigation is carried out between four types of dome shapes with different cap angle and flat plate, for a period of twelve months geographical location (Chennai - 13°N, 80°16′E). It was found that a dome shaped collector receives more sunlight compared to flat plate throughout the day. Typically, an increased irradiance of 50–100 W/m² was got during morning and evening time and a slight decrease of 10–40 W/m² during noon. The computation model uses finite element method and also takes into consideration of the dome surface area under shadow which is not facing sun directly. The developed model will be useful for predicting the performance of dome shaped solar collectors/stills.