Tag Archives: greenhouse fans

Selecting Fans for Optimal Air Flow

Greenhouse Fans Gothic Arch Greenhouse Selecting FansThough your greenhouse will help you extend the growing season, you’ll still have to monitor and maintain optimal growing conditions inside as the temperatures change outside.

Your plants will thrive in an environment where the temperature, humidity and air quality is controlled, and that starts with proper ventilation, both natural and automatic.

Fans are a common automated ventilation option. But using them to help create an ideal environment isn’t as simple as just installing them and turning them on.

To create the most successful conditions for your plants, you should keep these suggestions in mind when selecting fans for optimal air flow.

Choosing a Fan Type

When selecting fans, consider their efficiency. For example, circulating fans with blades that operate against zero static pressure are more efficient than exhaust fans designed to force air. Look for high-efficiency fans because they will be carrying a heavy workload. Fans with efficiencies of 14 to 16 are about average; better fans have efficiencies of 18 or higher. Tall plants and hanging baskets will reduce air flow, but fans with shrouds will help spread the flow of air over a greater distance.

Selecting Your Fan Layout

There are two types of layouts you can choose for your greenhouse fans, parallel or series. In a parallel layout, all fans are located at one end of the greenhouse and the air is pulled back, creating a loop. A series layout features fans in an alternating pattern, moving in toward the center. Because greenhouses may vary in size or located on uneven land, a series layout prevents fluctuations in heat or cold collecting in the higher or lower points.

Determining Fan Location

Locate fans near the center of the air mass that they are helping to move. For example, in greenhouses with floor or bench crops, place fans seven feet to eight feet above the floor. If there are hanging baskets in a greenhouse, fans should be located above or below basket level, where the air circulating will meet the least resistance. This will also prevent foliage from drying out by getting too much direct air.

Controlling Air Flow

Ideally, fans move air evenly throughout the greenhouse to help create the controlled environment you want for your plants. To do this, avoid erratic bursts of speed, such as when plants are “moving” as a result of the flow of air. Instead, generate a momentum of flow with the installation of multi-speed fans that are managed by a thermostat.

Directing Air Flow

Achieving horizontal air flow has long been a popular concept in greenhouse management. In recent years, vertical fans have gained more interest. Though they do level out temperatures from top to bottom, vertical fans don’t have the same effect across the entire growing area, which creates inconsistencies in plant growth. Horizontal fans are still prized for their ability to move air evenly and promote the movement of water through plants for their optimal health. 

Maintaining Your Performance

Simple preventive maintenance can help improve the flow of air in your greenhouse. Clean fan blades and the motor frequently to reduce dirt and dust buildup and prevent overheating. Inspect belts, particularly if you hear squeals and squeaks on startup. Replace belts with any cracks or frayed edges. Also check to see that fans are held securely in place with brackets or chains to keep them from moving out of place.

We can help you select the fans you need for your greenhouse application. Call us at 1-800-531-4769 or visit www.GothicArchGreenhouses.com!

Understanding Greenhouse Ventilation

Ensuring proper ventilation in your greenhouse is one of the most important concerns you’ll have since adequate and uniform air circulation is crucial to the success of your plants.

Ventilation is a primary concern because without it the greenhouse can quickly become an20141016_162428 oven in which no plant can survive.

When a greenhouse is properly ventilated, temperature, humidity, carbon dioxide and oxygen in the environment are consistent. That not only creates space for plants to flourish, but also air circulation can help in the pollination of plants, such as vegetables and ornamental plants, that are pollinated through the wind.

Fortunately, multiple ventilation supplies are available to help greenhouse owners manage their growing climates and extend their gardening seasons.

Here are some of the most common options and how they work:

Vents: These are the most common form of ventilation, and their placement can effectively and naturally draw air throughout the greenhouse. Placement of the vents in the roof pulls warm, moist air up and out, leaving cooler air at floor level. Opting for natural ventilation helps reduce energy costs, as fan ventilation can use an estimated 0.5 to 1 kilowatt hour per square foot per year. Taller structures are best suited for roof ventilation; lower-profile greenhouses will require forced cooling to get the same results.

Exhaust Fans and Shutters: Placed on opposite ends of the greenhouse, these two components work together to force outside air into the building. Exhaust fans create the pressure difference and cause air to flow. Fresh air comes through shutters placed at the opposite end, and the fans work to distribute it evenly throughout. As the air travels through the greenhouse is absorbs heat and is warmed gradually. Then as the fans exhaust the heated air, a slight vacuum is created, which draws in cooler outside air through louvers, open doors and cracks.

Circulation Fans: One of the most important accessories for a greenhouse, circulation fans are often used to move air throughout passively ventilated structures where venting is minimal. Aside from improving ventilation, circulation fans have multiple benefits. They help promote healthy plant growth by preventing stagnant air, which can cause fungus and disease to develop. Because they keep the air moving, there are no “hot” or “cold” spots; the temperature is uniform. They do carry an ongoing operational cost, and they should be cleaned and maintained to ensure they are properly functioning.

Evaporative Coolers: A powerful, compact and affordable ventilation option, evaporative coolers use the process of evaporating water to convert hot air into cooler temperatures. They work as outside air passes over water-saturated pads at one end of the greenhouse, which causes water to evaporate. Open windows and vents at the opposite end draw air in and let warm air escape. The temperature drops as the water evaporates and energy is lost from the air. This system works best in dry climates, but is a viable option for humid, tropical climates as well.

Greenhouse ventilation is important! If you have questions about what solution you should choose, call us today toll-free at 1-800-531-4769 to talk with one of our representatives or visit our website at www.GothicArchGreenhouses.com to learn more.