An alternate system runs on the fog or fine mist injected in to the intake air stream. Although several commercial systems can be found, growers can assemble and set up their own system using a high pressure piston pump and fog 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 which will reduce the effectiveness of the system and result in accelerated deterioration of the pads. The addition of an Greenhouse Auto Vent algaecide to the water supply can help in control.
It is desirable, especially in hard drinking water areas, to add a wetting agent to the 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 can 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 water. A flow rate 113 gallon each and every minute per linear foot of pad system ought to be provided to make certain adequate wetting.
In the most typical coolant system (fan and pad), the fans draw air through wet pads that expand the length of one endwall or sidewall. Aspen and covered cellulose are common pad materials that always have life of 1 to 3 years. Approximately one square foot of pad are is necessary for 20 square foot of floor area.