The Solar Desalination Greenhouse (SDGH) is a technology that transforms saltwater into freshwater, which can be used for irrigation or mineralized for drinking. This desalination process is facilitated by halophytes, plants that have adapted to grow in saline conditions. As these plants grow, they humidify the air within the greenhouse. The SDGH then uses passive and active dehumidification to produce freshwater from this humid air, without the need for energy. Active condensation can yield high amounts of water with the use of electrically powered cooling devices.
The SDGH also offers additional benefits such as the production of high-value halophytes and sea salt. It’s a flexible system with moderate installation and operating costs, and it can utilize renewable energy sources like solar or geothermal power.
The humidification-dehumidification process (HD) is a key component of the SDGH, making it a versatile solution for water desalination. This technology is particularly useful in arid regions where traditional farming methods are challenging due to high temperatures and freshwater scarcity.
Resources
Halophytes offer a sustainable alternative to conventional evaporators, providing benefits in terms of technology, economy, microclimate, and ecology. Besides enabling crop cultivation in areas with limited freshwater, the SDGH can produce surplus freshwater for external irrigation or drinking purposes.
An SDGH equipped with bio-based solutions can meet the demands of modern agriculture while minimizing environmental impact and maximizing profitability. A prototype SDGH measuring 8m by 4m can effectively control the microclimate and monitor evapotranspiration rates and halophytic biomass quality.
With a growing market for halophytes, local food supply can be ensured with minimal distance to consumers. The scalability of SDGHs combined with traditional greenhouses offers high adaptability for communities otherwise dependent on environmental conditions and irrigation water availability.
References
Desalination Greenhouse in general:
- Kabeel, A.E. and El-Said, E.M., 2015. Water production for irrigation and drinking needs in remote arid communities using closed-system greenhouse: A review. Engineering Science and Technology, an International Journal, 18(2), pp.294-301.
- Davies, P.A. and Paton, C., 2005. The seawater greenhouse in the United Arab Emirates: Thermal modelling and evaluation of design options. Desalination, 173(2), pp.103-111.
- Bourouni, K., Chaibi, M.T. and Al-Taee, A., 2011. Water desalination by humidification and dehumidification of air, seawater greenhouse process. Solar energy conservation and photoenergy systems, Encyclopedia of Life Support Systems. EOLSS.
Halophytes/Salicornia:
- Grattan, S.R., Benes, S.E., Peters, D.W. and Diaz, F., 2008. Feasibility of irrigating pickleweed (Salicornia bigelovii Torr) with hyper‐saline drainage water. Journal of environmental quality, 37(S5), pp.S-149.
- Glenn, E.P., Brown, J.J. and Blumwald, E., 1999. Salt tolerance and crop potential of halophytes. Critical reviews in plant sciences, 18(2), pp.227-255.
- Kong, Y. and Zheng, Y., 2014. Potential of producing Salicornia bigelovii hydroponically as a vegetable at moderate NaCl salinity. HortScience, 49(9), pp.1154-1157.
- Díaz, F.J., Benes, S.E. and Grattan, S.R., 2013. Field performance of halophytic species under irrigation with saline drainage water in the San Joaquin Valley of California. Agricultural Water Management, 118, pp.59-69.
Passive water harvesting:
- Sharan, G., Roy, A.K., Royon, L., Mongruel, A. and Beysens, D., 2017. Dew plant for bottling water. Journal of Cleaner Production, 155, pp.83-92.
- Maestre-Valero, J.F., Ragab, R., Martínez-Alvarez, V. and Baille, A., 2012. Estimation of dew yield from radiative condensers by means of an energy balance model. Journal of Hydrology, 460, pp.103-109.
- Khalil, B., Adamowski, J., Shabbir, A., Jang, C., Rojas, M., Reilly, K. and Ozga-Zielinski, B., 2016. A review: dew water collection from radiative passive collectors to recent developments of active collectors. Sustainable Water Resources Management, 2,
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