Agra Tech, Inc. products

Natural ventilation is provided by a combination of roof vents, wall vents, roll up walls, or drop walls. Wind pressure provides most of the energy for natural ventilation. Research has shown that above 80F there is normally measurable wind between 1 and 5 miles per hour.* As heated air expands and rises to the vent it escapes out the roof vent allowing cooler air in through a wall inlet or the roof vent itself to take its place.

Evaporative cooling converts hot air into a cool breeze using the process of evaporating water similar to how you feel when you step out of a swimming pool on a breezy day. In a standard greenhouse cooling system, exhaust fans pull hot air out of the greenhouse creating negative pressure inside the greenhouse. Fresh outside air is drawn through wetted pads and is cooled. This system is also referred to as a negative pressure cooling system. Evaporative cooling is environmentally-friendly since it uses no CFC`s or HCFC`s and costs about 70% less to operate than conventional air conditioning systems.

Agra Tech has developed Agra Kool II, a positive pressure cooling system. High volume jet-fans pull air through an evaporative cooling system and force it into the greenhouse through special convection tubes. This raises the static pressure inside the greenhouse. Integrated pressure sensitive ridge vents maintain the optimum pressure inside and allow heat to exit. The temperature differential with a positive pressure system can be as low as 2 degrees Fahrenheit compared to a 7 degree differential for negative pressure (fan and pad) system.*