Performance analysis of a humidification-dehumidification desalination system with a solar pond

Solar-driven humidification-dehumidification desalination offers a promising route to sustainable water production, particularly when integrated with solar ponds, which provide a cost-effective and stable heat supply. However, performance variations caused by seasonal meteorological fluctuations render a single operating condition insufficient for achieving year-round optimal efficiency. This study evaluates the performance of a humidification-dehumidification system with a solar pond under varying monthly meteorological conditions. Findings reveal a unique monthly optimal liquid-to-gas mass flow rate ratio that co-maximizes the gained output ratio and water productivity, with this ratio correlating directly to solar irradiance. The open-water system achieves a higher optimal gained output ratio and water productivity than its closed-water counterpart. The open-water configuration exhibits a monthly optimal gained output ratio ranging from a peak of 2.03 in April to a nadir of 1.80 in December. Its monthly optimal water productivity is proportional to solar irradiance, ranging from a peak of 156.10 kg/h in August (at 216.97 W/m2) to an annual minimum of 27.54 kg/h in December (at 101.87 W/m2). Crucially, the system demonstrates robust energy efficiency and remarkable operational stability, with the solar pond temperature fluctuating by less than 3.2 °C monthly and under 0.58 °C daily.