Optimization and Performance Analysis of Desiccant Wheel-Assisted Atmospheric Water Harvesting Processes

Abstract

To solve the fresh water scarce problem in dry regions, a desiccant wheel-assisted atmospheric water harvesting system is designed. Using water production rate as the index, studies are conducted to find the optimized air handling process under typical ambient conditions, considering influencing factors such as air flow rate ratio, stage numbers, and regeneration temperature. Based on a three-stage-desiccant wheel air humidification system, power consumptions are calculated for ideal and actual thermodynamic processes. Besides, using water production efficiency as the index, at the same water production rate, this system is compared with the traditional air-cooling method. The results show that this system has higher performances than the traditional air-cooling method. Under the discussed working conditions, the water production rate of the proposed system is in the range of 15.8—30.9 kg/h and the water production efficiency is in the range of 1.3—2.1 kg/(kW·h). The water production efficiency can be enhanced to 3.3—4.4 kg/(kW·h)when solar heater is used to replace heat pump systems. The proposed method can effectively enrich fresh water sources in dry regions.

Keywords

• atmospheric water harvesting
• multi-stage desiccant wheels
• process optimization
• energy consumption analysis
• water production efficiency