A preliminary feasibility study of using salt gradient solar ponds for desalination and other low temperature applications in north eastern Thailand

© 1987 Boonsrang DirecksatapornA computer model of salt gradient solar ponds has been developed and subsequently used as a tool to investigate the feasibility of using solar pond thermal energy for low temperature applications in North-eastern Thailand. The simulation results obtained indicate that, at 15 % heat extracted yearly, mean temperatures of an unlined uninsulated pond and a lined insulated pond are 67.5 °C and 77 °C respectively. This means that it is practically possible to use solar ponds as a heat source for all normal low temperature applications. Power generation applications are at present likely to prove uneconomic due to the low overall system efficiency estimated at less than 1 %. Modelling has also been evolved for prospective solar desalination systems and used to investigate whether the conventional solar still or a hybrid desalination system(HDS) is the more effective device for desalination applications in the area under consideration. Using these computer models optimum design parameters have been determined for both desalination systems. According to the results obtained from the models, using optimum design parameters as simulation inputs, it was found that the distillation rate of the HDS when supplemented by 15 % heat extracted from the solar pond is in the range of 9 to 11 litres/sq.m day for the unlined uninsulated pond and 12.5 to 15 lltres/sq.m day for the lined insulated pond. These are approximately about 3 or 4.5 times higher than the distillation rate obtained from a conventional solar still. No attempt was made to evaluate the economical feasibility of hybrid desalination systems as compared with conventional solar stills. This was mainly due to the lack of information available on economic considerations for this type of plant in Thailand. Further economic analyses are considered necessary before any firm conclusion can be drawn on which options are the most suitable for desalinating degraded water sources in rural area of Thailand