Expander-based Atmospheric Water Harvesting in the Tropics

Article type: Research Article

Authors: Subiantoro, Alison

Affiliations: Department of Industrial Engineering, KridaWacana Christian University (UKRIDA), Jl. Tanjung Duren Raya 4, West Jakarta, Indonesia. alison.ukrida@gmail.com

Abstract: A novel concept of using an expander to harvest atmospheric water is explored. The main advantages of this concept are its compactness and simplicity. Mathematical models were developed in this project to study the concept. The benchmark system had a crank and piston radii of 5 cm, rod length of 20 cm, operational speed of 60 rev/min, atmospheric temperature of 30°C and relative humidity of 80%. The expander was designed to expand the air to 0.7 bar and 0°C at the end of the expansion process. Because of the expansion, around 11.5 g of water was condensed for every 1 kg of air expanded. Most of the expander power was consumed during expansion to overcome the pressure difference across the two sides of the piston. The average power per cycle was 3.374 W. Therefore, the ratio of energy consumed and condensed water volume produced is 117 kWh/m3. The parametric study found that the ratio of energy and water volume was unaffected by the operational speed, increased linearly as the ambient air was hotter, decreased with ambient relative humidity and was unaffected by the expander size.

Keywords: Water, vapour, humidity, condensation, expander, tropics

DOI: 10.3233/AJW-170020

Journal: Asian Journal of Water, Environment and Pollution, vol. 14, no. 3, pp. 1-8, 2017