Solar Desalination Based on Micro Gas Turbines Driven by Parabolic Dish Collectors

This paper presents the preliminary design and techno-economic assessment of an innovative solar system for the simultaneous production of water and electricity at small scale, based on the combination of a solar micro gas turbine (mGT) and a bottoming desalination unit. To assess this system, a design model is developed to select the main design parameters for two different desalination technologies, reverse osmosis (RO), and multi-effect distillation (MED), aiming to exploit the available electricity and waste heat from the turbine, respectively. The results show that, from a thermodynamic standpoint, it is possible to exceed 65% solar energy utilization if both electricity and waste heat are used to produce fresh water. Nevertheless, the better thermodynamic performance of the fully integrated system does not translate into a more economical production of water. Indeed, the cost of water turns out lower when coupling the solar microturbine and reverse osmosis units only (between 3 and 3.5 €/m³), while making further use of the available waste heat in a multi-effect distillation system rises the cost of water by 15%.