Domestic solar hot water systems: Developments, evaluations and essentials for “viability” with a special reference to India

Following typical phases of any technology development, initially there have been research works focusing mainly on the solar hot water systems’ (SHWS) technology development then followed by economic aspects. This has resulted in techno-economically feasible standardized solar hot water systems. Owing to these favourable features, SHWS in general and Domestic SHWS (DSHWS) in particular attracted several promotional measures with a view to make them as the alternative for conventional water heating options in India. However, even after the implementation of these measures for more than two decades in India, the potentials-achievements difference remains to be extremely large, the reasons for which are attributed to the so-called “barriers for dissemination”. This paper presents a consolidated review of solar water heating related issues covering these technological developments, techno-economics, promotional measures, present dissemination status and barriers for dissemination, all with a special reference to the Indian context. Also presented in this paper is the identified need for “viability” studies of DSHWS and “essentials for viability evaluations of DSHWS” in multi-dimensional environment that aid in developing decision making tools to improve dissemination of DSHWS.