An alternate system runs on the fog or fine mist injected in to the intake air stream. Although a number of 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 applied on excessively warm, bright days. Temperature settings ought to be 5-10°F apart.

Algae growth in the pads may become a problem that may decrease the effectiveness of the machine and lead to accelerated deterioration of the pads. The addition of an Greenhouse Exhaust Fan algaecide to the drinking water supply will 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 material 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 lower in mineral content to prevent 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 program 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 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 needed for 20 square foot of floor area.