Optimization study of small-scale solar membrane distillation desalination systems (s-SMDDS)

Area of Science:

• Renewable Energy Systems
• Water Desalination Technologies
• Environmental Engineering

Background:

• Membrane distillation (MD) effectively uses low-grade thermal energy for desalination.
• Solar membrane distillation desalination systems (SMDDS) integrate solar thermal energy, addressing energy and water scarcity.
• Small-scale SMDDS (s-SMDDS) are suitable for decentralized freshwater production in arid regions.

Purpose of the Study:

• To determine the minimum cost design and operation for small-scale solar membrane distillation desalination systems (s-SMDDS).
• To analyze the economic viability and performance of s-SMDDS for freshwater production.

Main Methods:

• A systematic approach combining pseudo-steady-state equipment sizing and dynamic optimization using mathematical models.
• Analysis of two s-SMDDS configurations with different air gap membrane distillation module areas (11.5 m² and 23 m²).

Main Results:

• Lowest water production costs achieved were $5.92/m³ (500 kg/day) and $5.16/m³ (1000 kg/day).
• Optimal cases showed performance ratios of 0.85 and 0.91, and recovery ratios of 4.07% and 4.57%.
• Increasing the membrane mass transfer coefficient up to twofold significantly reduces production costs.

Conclusions:

• Optimized s-SMDDS present a cost-effective solution for freshwater production in remote arid areas.
• Solar-powered desalination is a promising technology for sustainable water resource management.
• Membrane properties critically influence the economic feasibility of s-SMDDS.