G. Krivokapich’s research while affiliated with New Mexico State University and other places

The operation of the Willard solar thermal power system is analyzed and evaluated. The 19 kW (25 hp) power system was coupled to a shallow well and sprinkler system near Willard, New Mexico irrigating approximately, 49 hectares. The specific performance of the major subsystems—collector array, thermal storage, and the organic working fluid Rankine cycle heat engine—were determined. Over the summer months, the daily collector array efficiency (based on direct solar radiation normalized in the plane of collector aperature) was nominally 25 per cent and heat engine rankine cycle efficiency 15 per cent. These conversion efficiencies coupled with the numerous system losses resulted in an overall efficiency of nearly 3 per cent on clear summer days. Electrical parasitic losses reduced the system's net power output by about 20 per cent on clear days and greater amounts on other days. The maintenance and repair effort was distributed evenly among the collector array and the heat engine.

The output capacity of the solar-thermal power system located near Willard, New Mexico was 19 kw (25 hp), with a primary application for irrigation pumping. Solar radiation was collected with north-south axis, east-west tracking, parabolic trough collectors having a total aperture area of 1275 m/sup 2/ (13,720 ft/sup 2/). Thermal storage was adequate for 20 hr. of power system operation utilizing a reaction-type turbine in conjunction with an organic Rankine-cycle heat engine. Operating efficiencies for the turbine component, heat engine, and the complete power system were 65-80 percent, 10-16 percent, and 1-3 percent, respectively. With the Willard system fully operational and near-term hardware improvement, an annual performance of 22 kw hr/m/sup 2/ of collector aperature area could be expected. Examples of component operation under variable environmental conditions are presented for the winter and summer seasons. Maintenance experience with the Willard system is also given.

The solar powered system located near Willard, New Mexico, generates mechanical or electrical power at a capacity of 19 kW (25 HP). The solar collection system incorporates east/west tracking parabolic trough collectors with a total aperture area of 1275 sq m (13,720 sq ft). The hot oil type thermal energy storage is sufficient for approximately 20 hours of power system operation. The system utilizes a reaction type turbine in conjunction with an organic Rankine cycle engine. Total collector field efficiency reaches a maximum of 20 percent near the winter solstice and about 50 percent during the summer. During the month of July, 1979, the system pumped 60 percent of the 35,300 cu m (28.6 acre-feet) of water delivered. Operating efficiencies for the turbine component, organic Rankine cycle engine and the complete power system are respectively 65 to 75 percent, 12 to 15 percent and 5 to 6 percent. Significant maintenance time was expended on both the collector and power systems throughout the operational period.

The capacity of the Willard Solar Power system is 19 kW (25 hp) and is capable of producing both the mechanical and electrical power. During the peak of the irrigation season, July 1979, the system pumped 60 percent of the 35,300 m³ (28.6 acre-feet) of water deliverd. The power system involves east/west tracking parabolic trough collectors, thermal energy storage sufficient for 20 hours of system operation and an organic Rankine cycle engine where the operating efficiencies are 20 percent near winter solstice for the collector fields, 12 to 15 percent for the engine and 5 to 6 percent as an overall system efficiency. Significant maintenance time was expended on both the collector and power systems throughout the operational period.