Integrated collector storage solar water heaters: survey and recent developments

The direct conversion of solar to thermal energy is highly efficient, more environmental friendly and economically viable. Integrated collector storage solar water heaters (ICSSWH) converts the solar radiation directly into heat at an appreciable conversion rate and in many cases using concentrating means. These systems are compact, aesthetically attractive and reasonable in construction and can reduce the environmental impact up to 40 %. They also have high collection efficiency factor and energy saving potential. Despite of many advantages, ICS solar water heaters suffer from high thermal losses in the night/overcast sky conditions. In this article, authors discuss the recently developed new and improved ICS designs and strategies used for reducing thermal losses from such devices, especially in non-collection period. The systems have been evaluated based on a followed categorization to non-concentrating, concentrating and systems with phase change materials.