Expander-based Atmospheric Water  Harvesting in the Tropics

Alison Subiantoro

doi:10.3233/AJW-170020

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.

Conflict of interest

The authors declare they have no competing interests.

References

Badr, O., O’Callaghan, P.W. and S.D. Probert (1985a). Multi-Vane Expanders: Geometry and Vane Kinematics. Applied Energy, 19, 159-182.

Badr, O., Probert, S.D. and P.W. O’Callaghan (1985b). Multi-Vane Expanders: Vane Dynamics and Friction Losses. Applied Energy, 20, 253-285.

Baek, J.S., Groll, E.A. and P.B. Lawless (2002). Development of a Piston-Cylinder Expansion Device for the Transcritical Carbon Dioxide Cycle. International Refrigeration and Air Conditioning Conference at Purdue, R11-8, 1-10.

Deng, Y. and A. Wheatley (2016). Wastewater Treatment in Chinese Rural Areas. Asian Journal of Water, Environment and Pollution, 13(4), 1-11.

Devres, Y.O. (1994). Psychrometric Properties of Humid Air: Calculation Procedures. Applied Energy, 48, 1-18.

Harriman III, L.G. (1990). The Dehumidification Handbook (2nd Edition), MuntersCargocaire: Amesbury, USA.

Henderson, P.C., Hewitt, N.J. and B. Mongey (2000). An Economic and Technical Case for a Compressor/Expander Unit for Heat Pumps. International Journal of Energy Research, 24, 831-842.

Khalil, A. (1993). Dehumidification of Atmospheric Air as a Potential Source of Fresh Water in the UAE. Desalination, 34, 587-596.

Lorentzen, G. (1994). Revival of Carbon Dioxide as a Refrigerant. International Journal of Refrigeration, 17, 292-301.

Meytsar, J. (1997). Method and Device for Producing Water by Condensing Atmospheric Moisture. World Intellectual Property Organization Patent WO 97/41937.

Moran, M.J. and H.N. Shapiro (2000). Fundamentals of Engineering Thermodynamics (4th Edition). John Wiley & Sons, Inc., New York, USA.

Robinson, D.M. and E.A. Groll (1998). Efficiencies of Transcritical CO2 Cycles With and Without an Expansion Turbine. International Journal of Refrigeration, 21, 577-589.

Shrivastava, B.K. (2016). Technological Innovation in the Area of Drinking Water for Treatment of Saline Water. Asian Journal of Water, Environment and Pollution, 13(3), 37-44.

Singapore’s National Environment Agency – http://www.nea.gov.sg/weather-climate/climate/weather-statistics. (accessed: November 2, 2016).

Tamura, I., Taniguchi, H., Sasaki, H., Yoshida, R., Sekiguchi, I. and M. Yokogawa (1997). An Analytical Investigation of High-Temperature Heat Pump System with Screw Compressor and Screw Expander for Power Recovery. Energy Conversion Management, 38, 1007-1013.

Wahlgren, R.V. (2001). Atmospheric Water Vapour Processor Designs for Potable Water Production: A Review. Water Research, 35(1), 1-22.

Previous article in this issue

Next article in this issue