An alternate system runs on the fog or good mist injected into the intake air stream. Although several commercial systems are available, growers can assemble and install their own system using a ruthless piston pump and fog nozzles. The basic components are demonstrated 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 should be 5-10°F apart.

Algae growth in the pads may become a problem which will decrease the effectiveness of the machine and lead to accelerated deterioration of the pads. The addition of an algaecide to the water supply can help in control.

It really is desirable, especially in hard drinking water areas, to add a wetting agent to the water to obtain more 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 ought to be clean and low in mineral content to avoid 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 program ought to be provided to make sure adequate wetting.

In the most typical cooling system (fan and pad), the fans draw air through wet pads that expand the Greenhouse Auto Vent length of 1 endwall or sidewall. Aspen and covered cellulose are normal pad materials that usually have life of one to three years. Approximately one square foot of pad are is necessary for 20 square feet of floor area.