Passively improving liquid sorbent based atmospheric water generation by integration of fuel cell waste products

• Published in: Journal of cleaner production Vol. 287; p. 125007
• Main Authors: Kwan, Trevor Hocksun, Shen, Yongting, Hu, Tianxiang, Gang Pei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10-03-2021
• Subjects: Atmospheric water generator; Fuel cell; Humid air physics; Liquid sorbent; Water recovery; Water recovery; Humid air physics; Liquid sorbent; Atmospheric water generator; Fuel cell
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2020.125007

Although interfacial atmospheric water generation is a new concept that can generate freshwater from renewable energy, its water generation rate is too low for widespread use. This paper proposes to integrate the fuel cell to a similar device but instead uses the electrochemically generated waste heat to drive the regeneration process of the liquid sorbent material. Furthermore, the electrochemically generated water is used to increase the relative humidity of the incoming air. Thus, by solely relying on the fuel cell waste products, water recovery rates that are theoretically higher than direct atmospheric water generation are achieved. A steady-state physics model based on the difference in water partial pressure to achieve water absorption and desorption is used to analyze the liquid sorbent device’s performance. Furthermore, the effect of various design parameters such as the salt mass fraction, the fuel cell operating power, the ambient relative humidity, etc. have been studied. Results demonstrate that up to 1.8 kg/h and 0.82 kg/(m2 h) of liquid water can be obtained by fuel cells with an operating temperature range that is consistent with the high-temperature proton exchange membrane fuel cell. This implementation would allow an FC waste heat utilization ratio of up to 0.8.
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•The fuel cell is integrated into the liquid sorbent-based water generator.•Electrochemical waste heat and water drive the process and increase water yield.•A model using the water partial pressure difference is developed for this system.•Up to 1.8 kg/h and 0.82 kg/(m2 h) of water were obtained by this system.•The proposed implementation is most compatible with the HT-PEMFC.