Purification of saline water using single and double slope solar still study of heat and mass transfer

Abstract

Water is the principal element for the survival of life on the earth. The water for the existence of human life should be in a specific range of parameters and is commonly known as potable water. There are many places on the earth especially coastal and arid regions, where scarcity of water is a big problem. There are regions where the water is available but it lacks the norms of potability, often known as salty or brackish water, thus not suitable for human consumption. Exponentially increasing population with expansion of industrialization and mechanization is lessening the availability of potable water in many regions specifically in developing countries. The human community is striving hard to conserve potable water as well as find ways to convert brackish water into potable one. There are many techniques developed so far, for purification of water viz. reverse osmosis, Electrodialysis, Multi stage flash (MSF) distillation Vapour compression desalination etc. Solar desalination is a process which utilizes the heat of solar radiation, which is free of cost and non-polluting, for the purification of water. Solar still is a device that uses solar energy to transform salty/brackish water into potable water. But it has low productivity and requires a large area due to which it is still not popular, and is one of the major concerns of the research community engaged in this field. However numerous researches have been carried out so far to overcome these deficiencies, still, the scope exists for improvement in many domains. In the work presented in this thesis, an attempt has been made to study and improvise single basin double slope and single slope solar distiller units to purify brackish water using solar energy as a primary energy resource. The key areas focussed in this work are cover inclination, the thermal absorptivity of water, energy storage, reduction in characteristic length, the surface tension of water, thin water film and surface area enhancement.