Economic feasibility evaluation of solar distillation systems based on the equivalent cost of environmental degradation and high-grade energy savings

摘要

Solar distillation systems have been found economically feasible in desalination of saline water. It is a simple and cost-effective low-carbon technology. Free of cost, non-polluting, non-exhaustible solar energy is used to produce distilled water inside a solar still. In this article, the usual economic analysis model has been modified by incorporating the factor of equivalent cost of environmental degradation and high-grade energy savings for solar stills. The unit cost of desalination of saline water is estimated to be US$ 0.034/L corresponding to 30.42% energy efficiency of a passive solar still. It decreases to USS 0.024/L using the modified model. Double-slope passive solar stills desalinate at a lowest cost of US$ 0.007/L. Due to higher capital cost of active solar stills, the unit cost of desalination of saline water is higher even if productivity is more. Effects of variation of energy efficiency, useful life, capital cost, etc. are also studied. The payback periods of the passive solar still are found to be in the range of 1.1 to 7.6 years if the selling price of distilled water decreases from US$ 0.18 to 0.04/L.