An alternate system uses a fog or good mist injected in to the intake air stream. Although many commercial systems are available, growers can assemble and install their own system using a ruthless piston pump and fog nozzles. The essential components are demonstrated in Fig. 1. A two-stage system managed by a two- stage thermostat allows more water to be applied on excessively warm, bright days. Temperature settings ought to 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 water supply can help in control.
It is desirable, especially in hard water areas, to add a wetting agent to the water to obtain more uniform wetting of the pads. A commercial material or liquid home detergent at the price of 2 tablespoons per 100 gallons may be used.
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 accustomed to recirculate the water. A flow rate 113 gallon per minute per linear foot of pad system should be provided to make sure adequate wetting.
In the most common 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 normal pad materials that always have life of one to 3 years. Approximately one square foot of pad are is needed for 20 square foot of floor area.
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