Solar energy desalination for arid coastal regions: development of a humidification–dehumidification seawater greenhouse

The long-term aim of our research is to develop humidification–dehumidification desalination technology for farms in arid coastal regions that are suffering from salt-infected soils and shortages of potable groundwater. The specific aim of our current study was to determine the influence of greenhouse-related parameters on a process, called Seawater Greenhouse, which combines fresh water production with growth of crops in a greenhouse system. A thermodynamic model was used based on heat and mass balances. The dimension of the greenhouse had the greatest overall effect on the 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 kWhm 3, while the narrow deep structure consumed 5.02 kWhm 3. Analysis of the local climate indicated that the structure should be built facing the NE direction. We are also in the process of building a commercial size Seawater Greenhouse at a site by the sea. The aim is to demonstrate the technology to local farmers and companies in the Arabian Gulf. The system will allow for the reclamation of salt-infected land by not relying, at all, on groundwater resources. 2003 Elsevier Ltd. All rights reserved.