Simulation Study of a Multilayer Membrane Distillation Unit Coupled to Heat Pump

Membrane distillation combines thermal and membrane techniques for freshwater preparation that can be an important solution to the shortage of fresh water in some regions of the world. The objective of this work is (1) to develop a concept of AGMD (air gap membrane distillation) using a flat plate type separator to limit inside heat loss, (2) to find the adequate coupling with a heat pump for the heat requirement and for the use with solutions highly concentrated in salts and (3) to look for paths towards the optimal configuration of this unit. Heat and mass transfers were modelled with EES (Engineering Equation Solver). The effect of operating parameters including the evaporator inlet temperature (hot channel Th), condenser inlet temperature (cold channel Tc) and the number of stage on the permeate flux were investigated. The simulation analysis revealed that flow of permeate increases significantly if the difference between the inlet temperature of the hot channel Th and the inlet temperature of the cold channel Tc and if the number of stages increases. Based on these simulations, a 3D model was built with SolidWorks. This multilayer AGMD unit will be fabricated and tested at the laboratory.