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 install their own system utilizing a high pressure piston pump and fog nozzles. The basic components are shown in Fig. 1. A two-stage system controlled by a two- stage thermostat allows more water to be employed on excessively warm, shiny days. Temperature settings should be 5-10°F apart.
Algae development in the pads may become a problem that will reduce the effectiveness of the machine and lead to 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 home detergent at the price of 2 tablespoons per 100 gallons may be used.
Water for the pads should be clean and lower in mineral content to avoid clogging and coating of the pads. A pump, pipes and gutters are accustomed to recirculate the water. A flow rate 113 gallon each and every minute per linear foot of pad program ought to be provided to ensure adequate wetting.
In the most typical cooling system (fan and pad), the fans draw air through wet pads that extend the length of one endwall or sidewall. Aspen and covered cellulose are common pad materials that usually have life of 1 to 3 years. Approximately one square foot of pad are is needed for 20 square ft of floor area.
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