Polygeneration in desalination by photovoltaic thermal systems: A comprehensive review

The progress in the production of desalinated water and other products such as electric power, cooling water/air, and heat from photovoltaic thermal (PV-T) and concentrated photovoltaic thermal (CPV-T) systems, often referred to as polygeneration, is reviewed in this paper. This review paper discusses the application of PV-T and CPV-T energy for desalination approaches such as humidification dehumidification (HDH), multi-effect distillation (MED), reverse osmosis (RO), solar stills, membrane distillation (MD), and mechanical vacuum compression (MVC). Current methods for assessing the economic viability of PV-T and CPV-T polygeneration systems, including the estimation of installation and balance-of-system cost, price per peak power, feed-in-tariff, and energy pay-back period are discussed. Full-scale and commercial PV-T and CPV-T systems applicable in desalination processes are also reviewed. Research and development activities on polygeneration PV-T and CPV-T systems have continued to improve. However, research on optimum generation of co-products from these systems needs to be intensified in order to ensure widespread practical application. Polygeneration from PV-T systems integrated with desalination have been shown to provide higher efficiencies in grid-connected or stand-alone applications than the single-product systems. For much higher efficiencies, the incorporation of nanofluids as the heat transfer medium and the use of absorbers that are less than 50% covered by PV module have been recommended. On the economic side, the installation costs of PV-T systems are still higher than those of their PV counterparts but PV-T systems provide less environmental impacts and cost reduction in the long run.