greenhouse air circulation and venting

Greenhouse Ventilation: Negative Air Pressure and Passive Systems

With negative air systems, warm air is sucked out with exhaust fans - air intake is through shutters. Sizing of equipment will depend upon the greenhouse dimensions, the season of the year, the crop and the transpiration rate of the crop.

Passive systems use roof vents and wall openings; air flow through a vent can either be up (warm air rising) or down (cold air dropping). Conditions at any given moment will determine the direction.

Outside wind and interior air circulation (typically horizontal air flow, HAF) will influence the performance of both negative air and passive systems.

The two systems can be used in the same greenhouse - but not at the same time. Negative systems require restricted air intake openings to achieve air flow speed. Because of this, open vents or sidewalls make exhaust fans almost completely ineffective.

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Timer Control Box for Light Dep - 4 Motors

Price: $1,475.00

24 hour timer unit for roll up shade systems (Call for a quote) used to adjust the photo-period for up to 4 motors.
Allows for several openings and closings in a 24 hour period - the benefit is that the curtain can be automatically raised after the sun sets. Canadian made. GREENHOUSE USE ONLY.

Timer Control Box for Light Dep

Price: $775.00

24 hour timer unit for roll up shade systems (Call for a quote) used to adjust the photo-period.
Allows for several openings and closings in a 24 hour period - the benefit is that the curtain can be automatically raised after the sun sets. GREENHOUSE USE ONLY.

Roof Vent Motor, 24 V. DC

Price: $745.00

These powerful units generate 294 newton-meters of torque - the limit switches are built-in and the shaft couplers are included in the price.
maximum amps: 8.5 m output shaft RPM: 1.3 Will open up to 180' of vent.
Allow 2 weeks for delivery, controller and mounting hardware are sold seperately.

12" Air Circulation Fan

Price: $445.00

Good air circulation creates temperature uniformity, reduces temperature stratification and promotes evaporation from the leaves (to lessen disease).
We offer Schaefer fans - engineered for high performance and longevity. Air is thrown in a tight conical pattern, ideal for horizontal air flow (HAF) applications. Two year limited warranty.
.1 HP, 115/230 volts (1.3/.65 amps) 1554 cubic feet of air per minute

20" Shutter-Style Exhaust Fan

Price: $349.00

Schaefer SFT-2000A 20" Shutter-Style Exhaust Fan, great for greenhouses . Low-maintenance, energy-efficient solution for low to medium airflow. Features an aluminum blade, powder-coated guards, durable aluminum shutters and an enclosed heavy-duty motor. Hardwired electrical connection required. Mounts flush to exterior wall.

Features and Specs:

Speed: RPM 14
Air Delivery: CFM 3,122
Volts: 115/230
H/P: 1/3
Amps: 3.8/1.9
Dimensions: L x W x H 12 ⅜" x 22 ¾" x 22 ¾"
Made in United States

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Greenhouse Light Dep Roll Up Motor, 156 nM

Price: $290.00

Use with roll-up walls.
Excellent reliability. Ideal for light deprivation and blackout systems.
24 volt DC motor, comes with built in limit switches. Torque: 156 Nm* - RPM: 2.2 - Amps: 4 max (7 amps max. load) Revolutions : 40 max - Weight: 4.6 kg. Comes with a coupler 1 3/8" roll up tube. Controllers not included.

*A netwon metre is a unit of torque in the metric system. 156 nM = 115.06 ft-lb.

Motor for Aluminium Shutter

Price: $268.00

Automate any shutter up to 48"

Inflation Unit

Designed in house! $224.00

75 CFM blower with mounting bracket. The base and plate are made of tough, heat-resistant and vibration-absorbing polycarbonate. The angles detach making it easier to slide them under existing polylock. The motor is attached independently of the plate for simpler blower changes and the oil port is exposed for easy maintenance.
Use with greenhouses between 750 and 2,000 square foot.
The brackets work with tubes diameters up to 2.15"

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Greenhouse Electric Roll Up Motor, 44 nM

Price: $198.00

Use with a roll up wall 100' or less.
Excellent reliability. Ideal for ventilation, light deprivation and blackout systems.
24 volt DC motor, comes with built in limit switches. Torque: 44 Nm - RPM: 4.5 - Amps: 2 (max: 4) - Revolutions: 40 - Weight: 3.5 Kg
Both couplers are used with 1-3/8" outside diameter tube.
Various install kits and controllers, sold seperately.

*A netwon metre is a unit of torque in the metric system. 44nM = 32.453 ft-lb.

Light Trap - 24"

Price: $185.00

Provide air exchanges while excluding light.

24" x 24" x 9-3/4" depth. American made. Excellent performance.

Easily assembled. Frame not included.

Please call for other sizes.

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