Environment Control System In A Greenhouse

Control systems can be very simple or very complex. Examples include:

1) The "original" environmental control systems were manual:

• Manually rolling up a side vent.
• Manually opening a roof vent or door.
• Manually turning on a heater or cooler.

2) Simple controllers operate from a thermostat in the greenhouse and:

• Automatically set day and night temperature ranges.
• Automatically open and close vents (side, roof, etc.).
• Automatically turn on or off heaters and coolers.

3) Step controllers operate from a thermostat in the greenhouse and:

• Automatically set day and night temperature ranges.
• Automatically control 1 or 2 heating stages (depends on # of heaters).
• Automatically control several cooling stages using cooling fans and
  pump(s) to wet the pads.

4) Sophisticated computers operate from a temperature sensor in the greenhouse and:

• Automatically set day and night temperature ranges.
• Automatically control heating equipment including boilers, root zone
  heating, heat retention curtains, etc.
• Automatically control other equipment including HAF fans, exhaust
  fans, vents, pad pumps, fogger systems, etc.
• Automatically control relative humidity.
• Automatically control shade curtains and artificial lighting depending on
  light requirements.
• Sophisticated computers can also monitor an external weather station and use
  data from that station to control internal conditions in the greenhouse.
• Data monitored includes: outside light, temperature, RH, rain and wind.
  Sophisticated computers can also operate the fertigator system
• Automatically using light quantity (e.g., X ml of solution/Y amt. of light)
• Automatically controlling timing of watering, duration of watering,
  nutrient solution pH and EC, misting, watering booms, etc.