An alternate system runs on the fog or great 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 essential components are proven in Fig. 1. A two-stage system controlled by a two- stage thermostat allows more water to be applied on excessively warm, shiny days. Temperature settings ought to be 5-10°F apart.

Algae development in the pads may become a problem that will reduce the effectiveness of the system and result in 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 include a wetting agent to the water to obtain more uniform wetting of the pads. A commercial material or liquid household detergent at the price of 2 tablespoons per 100 gallons can be used.

Water for the pads ought to be clean and lower in mineral content to avoid clogging and coating of the pads. A pump, pipes and gutters are accustomed to recirculate the drinking water. A flow rate 113 gallon each and every minute per linear foot of pad program ought to be provided to guarantee adequate wetting.

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