Greenhouse Auto Vent

An alternate system runs on the fog or good mist injected in to the intake air stream. Although a number of commercial systems are available, growers can assemble and set up their own system utilizing a ruthless piston pump and fog nozzles. The essential components are proven in Fig. 1. A two-stage system controlled 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 Greenhouse Auto Vent problem which will reduce the effectiveness of the machine and result in accelerated deterioration of the pads. The addition of an algaecide to the water supply will help in control.

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

Water for the pads should be clean and low in mineral content to prevent 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 system should be provided to guarantee adequate wetting.

In the most common coolant system (fan and pad), the fans draw air through wet pads that extend the length of one endwall or sidewall. Aspen and coated cellulose are common pad materials that always have life of 1 to three years. Approximately one square foot of pad are is necessary for 20 square ft of floor area.