Multi-Effect Solar Water Still with Evaporation Pressure Self-Reduction Capability

Abstract

The objective of this paper is to investigate the operation of multi-effect water still coupled to an evacuated heat pipe tube solar collector and small fluid piston energy converter. The solar collector is used to provide heating of the saline water in the still and also to drive the fluid piston converter. This converter operates as a pump to evacuate air from the still and reduce pressure inside the still which would result in the increased saline water evaporation rate. The mathematical model of operation of the proposed water desalination system was developed using a set of equations to describe the mass and energy balance for each stage of the still. A simulation was carried out in Matlab/Simulink environment in order to calculate the distillate productivity and temperatures in all stages of the still. The preliminary results demonstrate that the total productivity of the multi-effect still is strongly affected by the pressure inside the still. Currently, the physical model of the system being assembled on the test rig to validate theoretical results.