An alternate system runs on the fog or good mist injected in to the intake air stream. Although several commercial systems can be found, growers can assemble and set up their own system utilizing a high pressure piston pump and fog nozzles. The essential components are shown in Fig. 1. A two-stage system controlled by a two- stage thermostat enables more water to be applied on excessively warm, shiny days. Temperature settings should be 5-10°F apart.
Algae growth in the pads can become a problem that will decrease the effectiveness of the machine 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 add a wetting agent to the drinking water to obtain additional uniform wetting of the pads. A commercial materials or liquid home detergent at the rate 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 used to recirculate the drinking water. A flow rate 113 gallon per minute per linear foot of pad system ought to be provided to make sure adequate wetting.
In the most typical cooling 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 normal pad materials that usually have life of one to three years. Approximately one square foot of pad are is necessary for 20 square foot of floor area.
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