Simulation of fresh water production using a humidification-dehumidification seawater greenhouse

Abstract

A thermodynamic simulation study was performed on the influence of greenhouse-related parameters on a desalination process that combines fresh water production using humidification-dehumidification with the growth of crops in a greenhouse. With the system under study, surface seawater trickles down a porous front wall evaporator through which air is drawn into the greenhouse. The saturated air passes through a condenser, which is cooled using cold deep seawater or cool seawater coming out of the evaporators. Thermodynamic modeling of the seawater greenhouse system in our laboratory has shown that the dimension of the greenhouse had the greatest overall effect on water production and energy consumption. A wide shallow greenhouse, 200 m wide by 50 m deep gave 125 m3.d-1 of fresh water. This was greater than a factor of two compared to the worst-case scenario with the same area (50 m wide by 200 m deep), which gave 58 m3.d-1. Low power consumption went hand-in-hand with high efficiency. The wide shallow greenhouse consumed 1. 16 kWh.m-3, while the narrow deep structure consumed 5.02 kWh.m-3. The benefits of the development of the seawater greenhouse for arid regions are discussed.