Performance of a small wind powered water pumping system

Authors: Vick, Brian; Neal, Byron; Clark, Ray

Submitted to: Windpower
Publication Type: Proceedings
Publication Acceptance Date: 6/20/2008
Publication Date: 9/1/2008
Citation: Vick, B.D., Neal, B., Clark, R.N. 2008. Performance of a small wind powered water pumping system. In: Proceedings of Windpower 2008 Conference and Exhibition, June 1-4, 2008, Houston, Texas. 2008 CDROM.

Interpretive Summary: It is estimated that stand-alone water pumping systems (i.e. no utility grid connection) are still used for domestic use and livestock watering at several hundred thousand farms and ranches across the United States. In developing countries the need for stand-alone water pumping systems is not only the best option but the only option. While mechanical windmills are still the predominant way of pumping water from underground aquifers for people and livestock, other solar and wind powered water pumping systems are being installed in much greater numbers. Very good water pumping performance for moderate to deep pumping depths (165 to 330 feet) was demonstrated at the USDA-ARS Conservation and Production Research Laboratory near Bushland, TX, with a small wind turbine (only 7 foot rotor diameter). A 7 foot rotor diameter wind turbine on a 60 foot tower provided enough power to a helical pump to satisfy the water requirements of 120 beef cattle for a 165 foot well depth and 60 beef cattle at a 330 foot well depth (assuming wind resource at Bushland, TX, which is typical of the Great Plains). In 2005, our laboratory published a paper which showed a 10 foot diameter wind turbine connected to a helical pump performed well for providing water to livestock in the Great Plains, but that wind turbine had twice the blade rotor swept area (power generated by a wind turbine is directly proportional to its blade rotor swept area). As encouraging as these results are for this 7 foot blade rotor wind powered water pumping system, there are still concerns about the longevity of the helical pump used in the test, but we believe the lifetime of the pump can be increased with modifications to the controller. Although the main concern of the American public currently is the high cost of gasoline and diesel, there is a much more serious problem which is looming. That problem is the future severe water shortage in most of the U.S. due to: declining level of water aquifers and reservoirs, more and increasingly strong droughts, and an ever growing water demand by an increasing population in most of these areas (Southeastern, Southwestern, and Western U.S.). Of course using wind energy instead of using electricity generated from fossil fuels will also help in slowing climate change due to less green house gases being released into the atmosphere.

Technical Abstract: Lorentz helical pumps (Henstedt-Ulzburg, Germany) have been powered by solar energy for remote water pumping applications for many years, but from October 2005 to March 2008 a Lorentz helical pump was powered by wind energy at the USDA-ARS Conservation and Production Research Laboratory (CPRL) near Bushland, TX. The wind turbine used was a Southwest Windpower (Flagstaff, AZ) Whisper 100 (2.1 m or 7 ft rotor diameter) which generated 3-phase variable voltage, variable frequency AC electricity. The wind powered version required an additional controller manufactured by Lorentz to rectify the electricity to DC before entering the primary controller. For the Bushland, TX site, the wind powered helical pump system demonstrated the ability to pump enough water at a 50 m (164 ft) pumping depth to meet the daily requirements of 120 beef cattle and 60 beef cattle at a 100 m pumping depth. Modifications of the controller(s) are still needed to make the wind powered system comparable to the reliability and durability of the solar powered units.