Effect of Dimples on Solar Concrete Plate Collectors and its Comparison with Other Domestic Water Heating Systems

Abstract

Though solar water heater is an environment-friendly and a well-established effective method of heating water, yet it is not used on large scale in a country like India where abundant solar energy is available for most of the year. A large proportion of population prefers the use of electric geysers or stoves over solar water heaters as they have cheaper initial costs. Thus with an objective of low-cost solar collector water heater, an investigation is conducted on concrete as collector plate. In order to improve the efficiency of concrete plate collector, a serpentine tube is used instead of parallel tubes, with the addition of metal fibers in concrete mixture to improve its thermal conductivity and dimples are created on the serpentine tube to enhance heat flow from tube to water flowing through it. In order to calculate the exact effect of dimples on concrete plate collector, dimpled tube collector is compared with smooth tube collector. It is observed that dimples lead to an increase in outlet water temperature and improved efficiency for all water flow rates. Also in this paper, comparison of concrete plate collector with existing systems of domestic water heating for the bathing purpose is presented.