Section 5: Integration and Staging of Cooling Systems
During spring and fall, temperatures are cool at night and increase during the day due to the solar load. During these seasons, the cooling system may be integrated so that as the temperature reaches a certain set point (set by the greenhouse manager), the roof and side vents open to allow for passive venting. If the temperature continues to increase, the roof and side vents close, the louvered vents opposite the fans open, and the fans turn on to actively bring in cooler air from outside. If the temperature continues to increase, the sump pumps associated with the pads turn on and begin feeding water to the pads to lower the temperature of the air entering the greenhouse and to increase the cooling potential. This cyclic or integrated approach to cooling helps to reduce cooling costs. Two examples of staged cooling are shown below.
- Typical staging of cooling when greenhouse has vents and fan-and-pad system
Roof and side vents open → Roof and side vents close and exhaust fans on low with louvers open → Fans shift to high with louvers open → Fans on high with lovers open and water applied to pads
- Typical staging of cooling when greenhouse has vents and positive pressure cooling
Roof and side vents open → Roof and side vents open and positive pressure unit fans on → Roof vents open, side vents closed and positive pressure cooling on with water applied to pads
You are now at the end of Unit 6: Cooling Systems. Click here to take the self-exam.
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