EXALT

The aim and uniqueness of the EXALT project is to couple thermal desalination with hydroponic greenhouse cultivation via heat pumps to enable the use of saline water in arid subtropical areas for crop production without polluting the environment with brine.
In order to define the requirements for the system, baseline studies are carried out along the salinity gradients of the available irrigation water along the course of the lower Jordan River. The results of these studies are used to map the spatial distribution of greenhouse cultivation under temporal changes in water availability and salinity. Based on these data, the temperature and salinity tolerance ranges of selected plants in combination with different abiotic stress situations are investigated. Based on the environmental parameters and the tolerance ranges of the plants, a sensitive and latent cooling demand is determined. The cooling demand serves as a template to determine the key technical elements of the cooling circuit and to select an environmentally friendly refrigerant.
The heat discharged from the greenhouse supports the desalination process so that dehydrated salt can be removed from the water cycle. The condensate produced is fed into the irrigation system, resulting in exceptionally high water use efficiency. Detailed designs, developed in a modular fashion for three case study sites in each of the two countries, allow the systems to be evaluated and compared ecologically.
The EXALT project is jointly supported by the German Federal Ministry of Education and Research (BMBF) and the Israeli Ministry of Science and Technology (MOST) within the Middle East Regional Water Research Cooperation Program (MEWAC).