Thermodynamic and economic feasibility of solar ponds for various thermal applications: A comprehensive review

Solar energy technologies and their applications are as relevant today as they were in 1950s. A comprehensive review of the most recent studies having numerous references to the past research works on the thermodynamic and economic feasibility of solar ponds is presented in this communication. Thermodynamic models for the performance analysis of solar ponds and its validation with the experimental results by a number of researchers are highlighted. Expressions for estimation of energy and exergy efficiencies of all three zones of salt-gradient solar pond are presented. Need of the evaluation and revival of solar pond technology for continuous supply of large quantity of solar thermal energy for low temperature applications has been advocated. Some of these applications are domestic and industrial process heating, heating of building and greenhouse, refrigeration and air-conditioning, desalination and salt production, agriculture and aquaculture, and power generation. Usefulness of the alternative technology of salt-gradient solar ponds such as solar gel ponds, equilibrium solar ponds, and shallow solar ponds has also been incorporated. It has been explored that solar ponds have a great potential of saving a large quantity of energy from degradation as well as exergy destruction due to the use of ‘energy based on fossil fuels and electricity’ for the purpose of usual low temperature applications. In this way, solar ponds will prove to be helpful in minimizing the present alarming ecological problems and energy shortage by substituting a large fraction of high grade energy consumption.