Mathematical and experimental investigation of a solar humidification-dehumidification desalination unit

In this paper, performance of a proposed desalination system based on air humidification-dehumidification (HDH) is investigated theoretically and experimentally. To evaluate the performance and productivity of the proposed solar humidification-dehumidification desalination unit, a theoretical simulation model is developed in which the energy equations of each component are considered. Productivity of the proposed system at different operating times during the day is calculated in two periods. First one starts at 9 am and ends at 17 pm, while the second starts after preheating before entering the humidifier at 13 pm to 17 pm. The results show that the highest fresh water productivity is found to be in the second period. A comparison between experimental and theoretical results shows a good agreement and gives evidence that the proposed model is valid to be used under different boundary conditions. The results also show that when the system operates 4 h in a day with preheating before it gives higher productivity of about 22 L/day (11 L/day·m2 of collector) as a result of stored energy in the system since sunrise. The total cost per 1 l for the unit is 0.0578$.