An alternate system runs on the fog or good mist injected in to the intake air stream. Although many commercial systems are available, growers can assemble and set up their own system using a high pressure piston pump and fog nozzles. The essential components are shown 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 should be 5-10°F apart.
Algae growth in the pads can become a problem that may decrease the effectiveness of the system 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 drinking water areas, to add a wetting agent to the drinking water to obtain more uniform wetting of the pads. A commercial materials or liquid household detergent at the price of 2 Greenhouse Auto Vent tablespoons per 100 gallons may be used.
Water for the pads should 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 ought to be provided to assure adequate wetting.
In the most common cooling system (fan and pad), the fans draw air through wet pads that extend the length of 1 endwall or sidewall. Aspen and covered cellulose are normal pad materials that always have life of one to 3 years. Approximately one sq . foot of pad are is necessary for 20 square ft of floor area.