An alternate system runs on the fog or good mist injected in to the intake air stream. Although a number of commercial systems are available, growers can Greenhouse Exhaust Fan 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, shiny days. Temperature settings ought to be 5-10°F apart.
Algae growth in the pads can become a problem which will reduce the effectiveness of the machine and result in 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 water to obtain additional uniform wetting of the pads. A commercial material or liquid household detergent at the rate of 2 tablespoons per 100 gallons may be used.
Drinking water for the pads ought to 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 drinking water. A flow rate 113 gallon per minute per linear foot of pad system should be provided to make certain adequate wetting.
In the most common coolant system (fan and pad), the fans draw air through wet pads that extend the length of one endwall or sidewall. Aspen and coated cellulose are normal pad materials that usually have life of one to three years. Approximately one sq . foot of pad are is needed for 20 square ft of floor area.