An alternate system uses a fog or great mist injected in to the intake air stream. Although many commercial systems can be found, growers can assemble and install their own system utilizing 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 allows more water to be employed on excessively warm, shiny days. Temperature settings should be 5-10°F apart.

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

It really is desirable, especially in hard drinking water areas, to add a wetting agent to the drinking water to obtain more uniform wetting of the pads. A commercial materials or liquid household detergent at the price of 2 tablespoons per 100 gallons can be used.

Drinking water for the pads should be clean and lower in mineral content to avoid clogging and coating of the pads. A pump, pipes and gutters are used to recirculate the drinking water. A flow rate 113 gallon per minute per linear foot of pad program ought to be provided to ensure Greenhouse Exhaust Fan 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.