Modeling of humidification-dehumidification (HDH) desalination systems with bubblecolumn dehumidifier

Population growth and the industrialization of societiesare among the factors that significantly increase thedemand for freshwater consumption. Using desalinationdevices is one of the solutions to meet this demandincrease. Humidification-dehumidification (HDH)systems are superior to other desalination methods due totheir simple and flexible design, low costs, the ability touse low-temperature energy sources, and the possibility ofbeing used in remote areas. In the current study, themodeling of an HDH system with a bubble columndehumidifier has been done. Due to direct contactbetween the air and water bubbles, the bubble columndehumidifier has a much higher heat and mass transfercoefficient than conventional dehumidifiers. The effect ofdifferent parameters on system performance was studied.The gain output ratio (GOR) of ۳ is obtained with a toptemperature of ۶۵ and a bottom temperature of ۴۵.Increasing the high temperature has the opposite effect onthe GOR of the system. However, enhancing the watercarryingcapacity by air increases water production.Increasing the pipe length and the number of dehumidifiertrays increases the performance and cost of the system.Each set of operating parameters has a specific mass flowrate ratio to optimize system performance. This mass flowminimizes the imbalance in the dehumidifier, and in otherwords, the heat capacity ratio of the dehumidifier (HCRd)becomes equal to one.