An alternate system uses a 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 using a ruthless piston pump and fog nozzles. The essential components are shown in Fig. 1. A two-stage system managed 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 growth in the pads may become a problem that will decrease 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 really is desirable, especially in hard drinking water areas, to add 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 can be used.
Drinking water for the pads ought to be clean and lower 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 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 expand 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 needed for 20 square foot of floor area.
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