Solar desalination with a humidification-dehumidification cycle: performance of the unit

The closed air cycle humidification-dehumidification process was used for w ater desalination using solar energy. The circulated air by natural or forc ed convection was heated and humidified by the hot water obtained either fr om a flat plate solar collector or from an electrical heater. The latent he at of condensation was recovered in the condenser to preheat the saline fee d water, Two units of different sizes were constructed from different mater ials;. The productivity of these units was found to be much higher than tho se of the single-basin stills. Moreover, these units were capable of produc ing a large quantity of saline warm water for domestic uses other than drin king. No significant improvement in the performance of the desalination uni ts was achieved using forced air circulation at high temperatures. While at lower temperatures, a larger effect was noticed. This can be related to th e low heat and mass transfer coefficients at low temperatures and to the no n-linear increase in the water vapor pressure with temperature.