Modulating Vent Control
Passive roof and sidewall vents are commonly used in
greenhouses as the primary means of air exchange and cooling. This is in
contrast to buildings that use active fan ventilation, usually in conjunction
with air conditioning equipment. Many greenhouses also use active fan
ventilation, particularly those with double inflated poly roof systems due to
the difficulty of installing roof vents. In many greenhouse applications, the
enormous volumes of air exchange that are required for ventilation (up to one
complete air exchange per minute) make passive venting an effective and
efficient choice. However, several special considerations must be observed for
effective passive ventilation. The rate of ventilation for a passive venting
device is affected by:
- The amount that a vent is opened
- The vent direction with respect
to the current wind direction
- The current wind speed
To protect your vents, your structure, and your crop from the
effects of strong winds, the control system constantly monitors the current
outdoor conditions and will close or limit the vent openings in extreme
conditions. To maximize air exchange and cooling precision, the system can
compensate for the effects of wind speed and wind direction by managing windward
and leeward vents separately.Argus roof and sidewall passive ventilation programs include:
- Full span modulating control (0
-100% opening)
- Reaction tables to accelerate or
decelerate vent opening with respect to ventilation required
- Rain position opening limits
- Separate cooling and
dehumidification settings
- Evaporative cooling position
- Wind speed lockout
- Wind lockout release rates
- Windward/leeward control
- Low temperature opening
overrides for "winter freeze up" protection
- Time and position based vent
movement
- Vent compensation settings for
curtain systems
- Spray program overrides
- Minimum crack settings
- Up to 5 parallel vent outputs
with individual manual overrides can be controlled from one program
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