Submitted to: American Institute of Aeronautics and Astronautics
Publication Type: Proceedings
Publication Acceptance Date: October 31, 1997
Publication Date: N/A
Interpretive Summary: An ongoing problem for farmers and ranchers around the world is how to pump water reliably and inexpensively from a remote water well when utility electricity is not available. Extending transmission lines to a remote water well in the U.S. can be very expensive, and utility electricity is unavailable in many parts of the world. Although mechanical windmills have ebeen the preferred choice for remote water wells, and solar powered photo- voltaic systems have become increasingly popular, wind-electric systems appear to be the better choice for areas with a good wind resource. A wind-electric water pumping system consists of: a wind turbine, a tower, a pump controller, a submersible motor, and a centrifugal pump. Testing has been performed on a 1.5 kilowatt wind-electric water pumping system at the USDA-ARS Conservation and Production Research Laboratory in Bushland, TX, for over six years. For the past five years, this wind-electric system has sproven to be very reliable with an availability of 93%. Since utility supplied electricity is not the same as that supplied by the wind turbine, the pump curves supplied by the pump manufacturer should not be used in selecting a pump for a wind-electric system. For a wind-electric system, the pump selection was found to depend not only on the water pumping depth, but also on the wind resource of the location. Besides determining the optimum pump for the Bushland wind regime, selecting the optimum pump for other wind regimes is also shown in the manuscript. Although this wind-electric water pumping system has been shown to perform well at a reasonable cost in other published manuscripts, this paper shows this wind-electric system to also be reliable.
Technical Abstract: A 1.5 kW wind turbine has been continuously tested since 1992 at the USDA-ARS Conservation and Production Research Laboratory in Bushland, TX, for pumping water for domestic and livestock use. This wind turbine used a permanent magnet alternator that provided variable-voltage, variable- frequency, 3-phase AC electricity which powered off-the-shelf submersible motors and centrifugal pumps without the use of an inverter. Data that have been collected for the past five years include: flow rate, wind speed, pressure (simulated pumping depth), voltage current, frequency, and electrical power. Data were collected for four different pumps at pumping depths ranging from 20 m to 100 m. The optimum pump was found to be a function of the water well depth and the wind speed distribution. A chronological history of significant events and failures is also documented in the paper. This wind turbine had an availability of 93% over the past five years. The individual contributions to downtime were: problems with the wind turbine/controller (5%), icing of the blades (1%), problems with the motor/pump (1/2%), and miscellaneous (1/2%). After correcting initial start-up problems, the 1.5 kW wind turbine proved very reliable over the past five years.