Numerical simulation and performance investigation of an advanced adsorption desalination cycle

Low temperature waste heat-driven adsorption desalination (AD) cycles offer high potential as one of the most economically viable and environmental-friendly desalination methods. This article presents the development of an advanced adsorption desalination cycle that employs internal heat recovery between the evaporator and the condenser, utilizing an encapsulated evaporator–condenser unit for effective heat transfer. A simulation model has been developed based on the actual sorption characteristics of the adsorbent–adsorbate pair, energy and mass balances applied to the components of the AD cycle. With an integrated design, the temperature in the evaporator and the vapor pressurization of the adsorber are raised due to the direct heat recovery from the condenser, resulting in the higher water production rates, typically improved by as much as three folds of the conventional AD cycle. In addition, the integrated design eliminates two pumps, namely, the condenser cooling water and the chilled water pumps, lowering the overall electricity consumption. The performance of the cycle is analyzed at assorted heat source and cooling water temperatures, and different cycle times as well as the transient heat transfer coefficients of the evaporation and condensation. ► An AD cycle with internal heat recovery between condenser and evaporator. ► A P–T–C diagram provides an insight to cycle and performance evaluation. ► It gives a three-fold improvement in water production rate. ► It consumes only 1.38kWh/m3, and it is twice that of thermodynamic limit. ► At 55C (85C) heat input, it yields 8.1(26)m3 per ton of adsorbent per day.