Abstract
The need of small amounts of water daily in desert areas motivates the design of a humidifier-dehumidifier desalination portable unit using solar energy. The objective of this paper is to calculate the humidifier performance parameter (KaV) for various values of its exit temperature. KaV includes the mass transfer coefficient of the water K, the surface area of the packing a, and the volume V of the humidifier. A numerical method is employed to calculate the KaV of the humidifier; and NTU method to calculate the distilled water and exit temperatures, of the dehumidifier. The usual approach in analyzing the HDH is to select KaV and solve the mathematical model of HDH to find the exit temperatures and amount of distilled water. In this paper, instead of calculating the exit temperature of the water from the HD, we reverse this process. The KaV is calculated given the exit temperature of the HD, and the amount of the distilled water. The results of KaV variations for a range of 25-40 degrees C of exit temperature; and the corresponding amounts of the distilled water are presented for four cases of operating conditions of humidifier and dehumidifier: water mass rate, air flow rate; and inlet water temperature to the humidifier. The calculated value of KaV, for a given region and amount of water required, will be used to design the evaporator.