Submitted to: Solar Energy Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 17, 1996
Publication Date: N/A
Interpretive Summary: Providing water for livestock in remote locations is still a major problem in the world. Many farmers and ranchers depend on mechanical windmills to pump water for their livestock, and some farmers and ranchers are beginning to replace their aging windmills with wind-electric and/or solar-PV systems. Some utilities are also encouraging stand-alone alternative energy water pumping systems because of the expense of maintaining rural transmission lines. In this paper, two wind-electric and two solar-PV water pumping systems were compared in terms of performance and cost. The two wind-electric systems were found to provide enough water for 300 to 400 cattle at a 30 meter pumping depth if the wind resource was similar to that of Bushland, TX. The two solar-PV systems were found to provide enough water for 25 to 75 cattle at a 30 meter pumping depth if the sun radiation was similar to that of Bushland, TX. In terms of total cost per amount of water pumped, both wind-electric systems were found to be better than the solar-PV systems by a considerable margin. This paper will not only provide useful information to farmers and ranchers on the economics of buying a wind-electric or solar-PV system, it informs manufacturers of how their products compare to their competitors.
Technical Abstract: The water pumping performance of two wind-electric systems is compared to the water pumping performance of two solar-PV systems. The wind-electric systems were rated at 1.0 kW and 1.5 kW at a wind speed of about 12 m/s, and the rotor diameters were 2.75 m and 3.05 m, respectively. The solar-PV systems were rated at 0.1 kW and 0.9 kW at a radiation level of about 1000 W/sq. m2, and the total solar panel surface areas were 1 and 17 sq. m2, respectively. Both wind-electric systems powered 3 phase 230 V AC induction motors with centrifugal pumps. The smaller of the solar-PV systems powered a DC motor with a diaphragm pump, and the larger one powered a single phase 230 V AC induction motor with a centrifugal pump. Only a well pumping depth of 30 m was evaluated for both wind-electric and solar-PV water pumping systems. The 0.1 kW and the 0.9 kW solar water pumping systems can provide enough water for 25 to 75 cattle, respectively, ,if the incident solar radiation is similar to that of Bushland, TX. The 1.0 kW and 1.5 kW wind-electric water pumping systems can provide enough water for 300 to 400 cattle, respectively, if the wind regime is similar to that of Bushland, TX.