Design and fabrication of a portable and hybrid solar-powered membrane distillation system

Abstract

This paper addresses the development of portable and hybrid solar-powered membrane distillation (SPMD) system for producing freshwater in remote arid and/or coastal areas like in Saudi Arabia. It is a stand-alone system that only uses renewable solar energy to operate. Thus, the system is highly suitable to be implemented in remote arid and coastal areas without infrastructures or connection to the grid (water and power), but blessed with abundant solar irradiation. Because the system is portable, it can also be used for emergency case like a natural disaster (e.g. tsunami). The system uses Vacuum Multi-Effect Membrane Distillation unit from Memsys to desalinate the seawater or brackish water. The SPMD system is a hybrid system that combines thermal collectors and photovoltaic (PV) panel. The thermal collectors convert solar irradiation into thermal energy to drive the Memsys process, whereas PV panel converts solar irradiation into electrical to power electrical equipment. The overall operations of the system were governed by Programmable Logic Controller. The innovation of this system is the design of a hybrid solar desalination system that is portable and reliable. The system can also be considered as a “green” and sustainable desalination technology. To study the performance of the system, small-scale tests have been conducted at the Engineering College – King Saud University, Saudi Arabia. The system ran successfully by only utilizing solar energy. The total volume distillate output during the test was approximately 70 L with an approximate conductivity of 4.7 μS/cm. The average distillate output rate was 11.53 L/h with the maximum of 15.94 L/h at noon time, whereas the distillate flux was in the range of 1.5–2.6 L/m2 h.