Low energy adsorption desalination technology

Adsorption-based desalination (AD) is attracting increasing attention because of its ability to use low-grade thermal energy to co-generate fresh water and cooling. In this paper, the working principle of the AD technology and the possible operation cycles of AD system have been described. A thermodynamic model has been developed in order to study the operational parameters that influence the fresh water production rate (FWPR) and energy consumption of silica gel based AD system. Water adsorption on the silica gel is modelled using a Langmuir isotherm and the factors studied are the heating and cooling water temperatures, which supply and remove heat from the silica gel respectively, and the set temperature of the evaporator. The result shows that the cooling water temperature has far more significant impact on the both water productivity and energy consumption compared to the heating water temperature. The paper also discusses in detail the impact of evaporator temperature on the thermodynamic cycle when the system is operated in desalination mode only.