An alternate system uses a fog or fine mist injected into the intake air stream. Although many commercial systems can be found, growers can assemble and install their own system using a ruthless piston pump and fog nozzles. The basic components are demonstrated in Fig. 1. A two-stage system controlled by a two- stage thermostat enables more water to be applied on excessively warm, bright 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 system and result in accelerated deterioration of the pads. The addition of an algaecide to the drinking water supply will help in control.
It is desirable, especially in hard drinking water areas, to include a wetting agent to the water to obtain more uniform wetting of the pads. A commercial materials or liquid household detergent at the price of 2 tablespoons per 100 gallons can be used.
Drinking water for the pads ought to be clean and low in mineral content to prevent clogging and coating of the pads. A pump, pipes and gutters are accustomed to recirculate the water. A flow rate 113 gallon per minute per linear foot of pad program should be provided to ensure adequate wetting.
In the most typical coolant system (fan and pad), the fans draw air through wet pads that lengthen the length of one endwall or sidewall. Aspen and coated cellulose are common pad materials that usually have life of one to 3 years. Approximately one square foot of pad are is necessary for 20 square feet of floor area.
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