An alternate system runs on the fog or fine mist injected in to the intake air stream. Although a number of Greenhouse Auto Vent commercial systems are available, growers can assemble and install their own system using a ruthless piston pump and fog nozzles. The basic components are proven in Fig. 1. A two-stage system controlled 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 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 will help in control.
It is desirable, especially in hard water areas, to add a wetting agent to the drinking water to obtain additional uniform wetting of the pads. A commercial materials or liquid household detergent at the price of 2 tablespoons per 100 gallons may be used.
Water for the pads ought to be clean and low in mineral content to prevent clogging and coating of the pads. A pump, pipes and gutters are accustomed to recirculate the water. A flow rate 113 gallon each and every minute per linear foot of pad program should be provided to make certain adequate wetting.
In the most common 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 common pad materials that usually have life of one to 3 years. Approximately one sq . foot of pad are is needed for 20 square ft of floor area.