An alternate system runs on the fog or good mist injected into the intake air stream. Although a number of commercial systems can be found, growers can assemble and install their own system using a high pressure piston pump and fog nozzles. The essential components are demonstrated in Fig. 1. A two-stage system controlled by a two- stage thermostat allows more water to be applied on excessively warm, shiny days. Temperature settings should be 5-10°F apart.

Algae development in the pads can become a problem that may reduce the effectiveness of the machine and lead to accelerated deterioration of the pads. The addition of an algaecide to the drinking water supply can help in control.

It is desirable, especially in hard drinking water areas, to add a wetting agent to the drinking water to obtain additional uniform wetting of the pads. A commercial material or liquid home detergent at the price of 2 tablespoons per 100 gallons can be used.

Drinking water for the pads should be clean and low in mineral content to prevent clogging and coating of the pads. A pump, pipes and gutters are used to recirculate the water. A flow rate 113 gallon per minute per linear foot of pad program should be provided to make sure adequate wetting.

In the most typical coolant system (fan and pad), the fans draw air through wet pads that lengthen the length of 1 endwall or sidewall. Aspen and covered cellulose are normal pad materials that always have life of one to three years. Approximately one sq . foot of pad are is necessary for 20 square feet of floor area.

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