An alternate system uses a fog or great mist injected into the intake air stream. Although a number of commercial systems can be found, growers can assemble and set up their own system utilizing a ruthless piston pump and fog nozzles. The essential components are proven in Fig. 1. A two-stage system managed by a two- stage thermostat enables more water to be applied on excessively warm, bright days. Temperature settings ought to be 5-10°F apart.
Algae growth in the pads may become a problem that will reduce the effectiveness of the system and result in accelerated deterioration of the pads. The addition of an algaecide to the drinking water supply can help in control.
It really is desirable, especially in hard water areas, to include 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 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 used to recirculate the drinking water. A flow rate 113 gallon each and every minute per linear foot of pad system ought to be provided to guarantee adequate wetting.
In the most common coolant system (fan and pad), the fans draw air through wet pads that prolong the length of one endwall or sidewall. Aspen and coated cellulose are common pad materials that always have life of 1 to 3 years. Approximately one sq . foot of pad are is necessary for 20 Greenhouse Auto Vent square ft of floor area.