Typical daily production ranges for small systems
Production varies widely by technology, sun availability, design, and feedwater salinity. Rough daily ranges for small-scale systems are:
- Simple solar stills (household, passive): 2–20 liters per square meter of still area per day under good sun conditions.
- Small PV-RO units (compact, off-grid): 50–500 liters per day depending on PV capacity, pressure pumps, and membrane size.
- Small thermal HDH or solar-thermal units: 20–200 liters per day per installation, depending on collector area and efficiency.
Factors that affect output:
- Solar irradiance: clear, sunny locations produce much more than cloudy regions.
- System sizing: larger collectors, more PV panels, or bigger membranes increase capacity.
- Pre-treatment and maintenance: clean systems operate close to rated output; fouling reduces productivity.
Practical considerations:
- For a household, a combined approach (solar stills for emergency use plus PV-RO for daily needs) may be effective.
- Community and institutional needs often require modular systems that can be expanded.
- Including storage (water tanks, battery-backed PV) smooths supply and increases usable daily output.
Consulting local installers and running a simple water demand and solar resource assessment helps determine realistic daily production for a particular site.