Recent technological advancements in membrane distillation and solar stills: preheating techniques, heat storage materials, and nanomaterials — a detailed review

Abstract

Freshwater and energy are critical components for the growth and progress of societies. The scarcity of freshwater and rapid population growth, especially in remote countries, has led to an urgent need to develop desalination technologies in order to raise its productivity and reduce its energy consumption rates. Membrane distillation is one of the effective methods characterized by its high productivity, but its disadvantage by higher electricity consumption. Also, solar stills are one of the sustainable and economical technologies, but the disadvantage by lower productivity. Accordingly, this manuscript dealt with a comprehensive review and detailed comparison of the most important modifications and innovations that were made to the design of the membrane distillation units, which aim to reduce electricity consumption rates, as well as the design of solar stills, which aims to maximize the productivity and efficiency. This was done by providing a detailed comparison of the most important three axes of modifications and innovations that were addressed by recent previous studies on the design of membrane distillation units and solar stills, and their statement as follows: preheating technology, use of the thermal storage materials, and nanomaterials technology. Finally, based on this review, the authors make some recommendations for future work in the field of solar and membrane desalination.

Optimal design of the stand-alone developed hybrid system for producing pure water and drying the plants for remote regions

“…This section provides a detailed description of the model equations for simulating the performance of photovoltaic/thermal (PV/T) panel. Thermal efficiency of PV/T panel ηth calculated as [54][55][56][57]:…”

“…where; is the PV panel surface area (m 2 ), I(t) is solar irradiation intensity (W/m 2 ), ̇ is the useful thermal energy within PV/T panels (W) which calculated as [54][55][56][57]:…”

“…) is calculated as [46,48]: (56) Drying unit dehumidification coefficient of performance is calculated as [46,48]:…”

Grand Challenges in Membrane Distillation for Desalination and Water Recovery

“…Solar-powered membrane distillation (SPMD) uses solar collectors to meet the thermal as well as electrical requirements of the MD process [39]. Paraffin wax can be used to store solar thermal energy, which could be used at night time, and this increased the cumulative yield by 43.2% and improved the GOR by 34.4% [40]. However, solar radiation varies seasonally and during each day, leading to a permeate flux variation which cannot be predicted.…”

Experimental Investigation of the Innovative Small Hybrid Desalination Plant Powered by PVT Panel for Remote Regions

“…Abdelgaied et al [21] conducted the behavior of an HDH-RO desalination plant powered by PVT panels and solar collectors. Abdelgaied et al [22] presented the comprehensive modification technology that was conducted on the membrane distillation which aimed to improve the rate of permeate water produced from reverse osmosis desalination systems. Abdelgaied et al [23] studied the performance of a small hybrid HDH-RO desalination plant powered by a solar dish concentrator and PVT panels for remote regions.…”