Main categories at a glance
Solar desalination systems fall mainly into two broad families: solar-driven thermal desalination and solar-powered membrane desalination. Within these families there are several common designs:
- Solar thermal systems:
- Solar stills (passive, basin-type)
- Humidification–dehumidification (HDH)
- Solar-assisted multi-effect distillation (MED)
- Solar-assisted multi-stage flash (MSF) in large plants
- Solar-powered membrane systems:
- Photovoltaic (PV) electricity driving reverse osmosis (RO)
- Electrodialysis (ED) powered by PV
- Pressure-retarded osmosis and related hybrid membrane techniques
There are also hybrid systems that combine thermal and membrane approaches or add battery and thermal storage to improve reliability.
Choosing between types depends on:
- Feedwater quality: membranes can be sensitive to fouling, while thermal methods tolerate higher salinity.
- Scale: RO is dominant at medium-to-large scales for desalinating seawater efficiently when powered by reliable electricity.
- Location and resources: thermal methods are attractive where waste heat or direct solar heat is available; PV-RO suits locations with good solar electricity and low-maintenance needs.
- Budget and technical skills: simpler thermal units work well for households and small communities; larger plants need skilled operation and pre-treatment systems.
Understanding these categories helps identify the right match for local water needs, available sunlight, and maintenance capacity.