A framework for evaluating the topic
Planning note: These methods are not direct substitutes; outdoor temperature-humidity, solar load, crop and geometry shape a staged strategy.
Compare the roles and limits of natural ventilation, mechanical exhaust, evaporative cooling and shading under different climates. This resource provides general technical information. Final capacity, equipment and implementation choices require engineering calculations based on site and project data.
Natural vents use wind and buoyancy; insect screens alter free area and pressure loss and may reduce expected air exchange.
A fan-pad system approaches outdoor wet-bulb temperature, so available cooling decreases as outdoor humidity rises.
Shading reduces solar load but does not remove moisture. Controls stage shade, vents, fans and pads without conflicting commands.
Topics covered in technical assessment
Roof and side vent area
Natural vents use wind and buoyancy; insect screens alter free area and pressure loss and may reduce expected air exchange.
Wind direction and buoyancy
A fan-pad system approaches outdoor wet-bulb temperature, so available cooling decreases as outdoor humidity rises.
Exhaust airflow and static pressure
Shading reduces solar load but does not remove moisture. Controls stage shade, vents, fans and pads without conflicting commands.
Pad area and face velocity
Natural vents use wind and buoyancy; insect screens alter free area and pressure loss and may reduce expected air exchange.
Outdoor wet-bulb condition
A fan-pad system approaches outdoor wet-bulb temperature, so available cooling decreases as outdoor humidity rises.
Shade factor and position
Shading reduces solar load but does not remove moisture. Controls stage shade, vents, fans and pads without conflicting commands.
Insect-screen pressure loss
Natural vents use wind and buoyancy; insect screens alter free area and pressure loss and may reduce expected air exchange.
Control stages and conflicting commands
A fan-pad system approaches outdoor wet-bulb temperature, so available cooling decreases as outdoor humidity rises.
Planning and comparison logic
Compare the roles and limits of natural ventilation, mechanical exhaust, evaporative cooling and shading under different climates.
| Input to verify | Effect on the decision | How to verify it |
|---|---|---|
| Roof and side vent area | Natural vents use wind and buoyancy; insect screens alter free area and pressure loss and may reduce expected air exchange. | Pad area and face velocity |
| Wind direction and buoyancy | A fan-pad system approaches outdoor wet-bulb temperature, so available cooling decreases as outdoor humidity rises. | Outdoor wet-bulb condition |
| Exhaust airflow and static pressure | Shading reduces solar load but does not remove moisture. Controls stage shade, vents, fans and pads without conflicting commands. | Shade factor and position |
Common mistakes
Shade factor and position
A fan-pad system approaches outdoor wet-bulb temperature, so available cooling decreases as outdoor humidity rises.
Insect-screen pressure loss
Shading reduces solar load but does not remove moisture. Controls stage shade, vents, fans and pads without conflicting commands.
Control stages and conflicting commands
Natural vents use wind and buoyancy; insect screens alter free area and pressure loss and may reduce expected air exchange.
Why does this matter in your project?
Planning note: These methods are not direct substitutes; outdoor temperature-humidity, solar load, crop and geometry shape a staged strategy.
This resource provides general technical information. Final capacity, equipment and implementation choices require engineering calculations based on site and project data.
Explore the related systemTechnical references
Frequently Asked Questions: Greenhouse Ventilation, Fan-Pad and Shading Systems
How should roof and side vent area be assessed?
Natural vents use wind and buoyancy; insect screens alter free area and pressure loss and may reduce expected air exchange.
How should wind direction and buoyancy be assessed?
A fan-pad system approaches outdoor wet-bulb temperature, so available cooling decreases as outdoor humidity rises.
How should exhaust airflow and static pressure be assessed?
Shading reduces solar load but does not remove moisture. Controls stage shade, vents, fans and pads without conflicting commands.
How should pad area and face velocity be assessed?
Natural vents use wind and buoyancy; insect screens alter free area and pressure loss and may reduce expected air exchange.
How should outdoor wet-bulb condition be assessed?
A fan-pad system approaches outdoor wet-bulb temperature, so available cooling decreases as outdoor humidity rises.