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Trough Plants: Kramer Junction
Cleaning

The most effective method of cleaning the collectors is to point them upward when rain or snow is predicted. Snow is reported to do an especially good job. However, the site is sunny 98 percent of the time, so other cleaning methods are required.

Washing is done once per week during peak summer season, using demineralized water. The water is demineralized on site. Two washing methods are used: the classic deluge wash, and the twister method which is more effective, but takes longer and costs more, so it is not done every cleaning. Both methods use less than one-fourth gallon of water per square meter of collector area for each washing.

The twister method is almost as good as natural snow cleaning. It uses a tractor with twirling nozzles, towing a water tank.


Figure 1. Twister method of washing the collectors. NREL ]

Figure 1 shows the twister method. Notice that water collects a little bit at the bottom of the collector. Every 2 or 3 years, manual cleaning of the bottom edge of the collectors is performed, using a hard brush, to remove gradual buildup.

For the deluge method, the collectors face each other so that two rows of collectors are washed at once. A large tanker truck with fixed sprayers drives between the collectors (Figure 2).


Figure 2. Deluge method of washing the collectors, using a water truck. NREL ]


Figure 3. Newer deluge washing truck, with improved spray nozzle positions. NREL ]

The cost of deluge washing is US $ 0.14 per square meter of collector area per year.

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