An alternate system uses a fog or great mist injected into 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 Greenhouse Exhaust Fan nozzles. The basic components are proven in Fig. 1. A two-stage system managed by a two- stage thermostat enables more water to be employed on excessively warm, shiny days. Temperature settings ought to be 5-10°F apart.
Algae growth in the pads can 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 water supply will help in control.
It really is desirable, especially in hard water areas, to include a wetting agent to the drinking water to obtain more uniform wetting of the pads. A commercial materials or liquid home detergent at the rate of 2 tablespoons per 100 gallons may be used.
Water for the pads should be clean and low 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 per minute per linear foot of pad program should be provided to ensure adequate wetting.
In the most typical cooling system (fan and pad), the fans draw air through wet pads that lengthen the length of 1 endwall or sidewall. Aspen and coated cellulose are normal pad materials that usually have life of 1 to three years. Approximately one square foot of pad are is necessary for 20 square ft of floor area.