Refrigeration system optimization for drinking water production through atmospheric air dehumidification

Drinking water availability is one of the emerging challenges of the twenty-first century. Different technologies are investigated as possible sources of water for the arid regions. Atmospheric water vapor processing is a developing approach whose aim is to cool air to condensate the water present in the atmospheric moisture. Air dehumidification allows obtaining pure drinking water for geographical regions far from sea, rivers, and lakes. This chapter presents the optimization of a refrigeration system for drinking water production through atmospheric air dehumidification. The system uses a fan to force the air through a heat exchanger, in which it is cooled. The water vapor condensates on the cooled heat exchanger surfaces and it is collected by gravity in a tank. The system’s aim is to condensate the maximum water quantity achievable for every atmospheric air condition, represented by temperature, humidity, and pressure. Thus, a mathematical model is defined to determine the optimal atmospheric air flow that maximizes the condensed water production for every atmospheric air condition. Furthermore, to consider the atmospheric condition hourly profiles of the refrigeration system installation site, three air flow control strategies are proposed: hourly, monthly, and yearly. An experimental campaign is set up to validate the model. Experimental test results show that it accurately predicts the drinking water production (gap between -5.6 and +4.1 %). Finally, the case study of a refrigeration system installed in Dubai, United Arab Emirates, is presented to assess and compare the proposed three air flow control strategies.