![fan and pad system greenhouse fan and pad system greenhouse](http://www.jlgreenhousesupplies.com/uploads/image/20180522/14/88-greenhouse-cooling-system-1.jpg)
These situations may require both dehumidification and cooling simultaneously, so wet pad and fans aren’t a viable option. They also insulate the greenhouse, causing temperatures to rise. Blackout screens make it much harder to ventilate effectively. Many greenhouse operators use blackout screens to control day length or reduce light pollution. During these periods, opening the greenhouse to reduce humidity is inefficient and often won’t result in a reduction at all, leaving the plants wet and susceptible to diseases. Greenhouse dehumidifiers are designed to reduce humidity when ventilation isn’t an option – overnight, or during cold, cloudy, rainy, or humid days. This is an effective method when outdoor conditions are favorable, meaning comfortable temperatures and relatively dry air, which isn’t always the case. Traditionally, growers would control humidity by opening greenhouse vents or windows, to let the humid air out.
![fan and pad system greenhouse fan and pad system greenhouse](https://d3i71xaburhd42.cloudfront.net/eeca812a364922f8afa31f10beebf61b768f594f/4-Figure5-1.png)
The unit sucks in humid air, runs it through a cold coil, which causes water to condense, and releases dry air back into the greenhouse. Refrigeration-based dehumidifiers, like DryGair, remove water from the air using condensation. How Dehumidifiers Workĭehumidifiers have one task – to remove water vapor from the air and reduce relative humidity. During the day, if relative humidity is lower outside, growers can use a wet pad to reduce temperatures, while ventilating to regulate humidity.įor greenhouses facing high temperatures in humid regions, it’s best to look for dry cooling solutions. This doesn’t mean wet pad and fan systems aren’t effective. So the colder it is, the less cooling you’ll get.
![fan and pad system greenhouse fan and pad system greenhouse](http://sc01.alicdn.com/kf/HTB1an2GHVXXXXXLXpXXq6xXFXXX2/202664311/HTB1an2GHVXXXXXLXpXXq6xXFXXX2.jpg)
![fan and pad system greenhouse fan and pad system greenhouse](http://i.ytimg.com/vi/Obn0-lk4nUo/maxresdefault.jpg)
It’s also apparent that the amount of cooling wet pads provide increases at higher temperatures. But at lower relative humidity levels, the cooling capacity increases. In the table below, you can see that at 100% relative humidity, pad and fan systems provide no temperature reduction at all. High humidity may lead to dew point condensation in the greenhouse and increases the risk of disease outbreaks. This not only makes the system ineffective, but also dangerous. So using a wet pad and fan, during humid or cold periods, will give less cooling and add water to the air. When the air is humid, less evaporation can occur, making the system less effective. When the air is dry, water evaporates rapidly, providing a more intense cooling effect. This is because evaporative cooling relies on the difference between outdoor and indoor conditions. When conditions outside are humid or cold, pad and fan systems lose effectivity and provide a much lower cooling capacity. So wet pad and fan systems may not provide the desired results. But there’s a problem – in these regions, humidity is often high during the night. However, some greenhouses do require cooling at night, mostly in tropical regions. Providing heat relief means pad and fan systems are mostly necessary during hot days with high radiation. The fans blow the cool air into the greenhouse, leading to an overall drop in temperature. The air is then blown through the pad, which constantly evaporates water, creating a cooling effect. This is an effective way to relieve the heat during hot summer days and provide plants with the best climate conditions.įan and pad cooling systems use exhaust fans to suck air from outdoors into the greenhouse. Pad and fan systems cool down greenhouse temperatures, using evaporative cooling. Dehumidifiers require a closed greenhouse – pad and fan systems rely on air exchange with the outdoors.Dehumidifiers remove water from the air – wet pad and fan systems add water.Pad and fan systems and dehumidifiers have opposite functions, making them negate each other’s operation: The short answer is – they shouldn’t run simultaneously. Growers often ask if, and how, dehumidifiers can work in conjunction with wet pads. Why Greenhouse Dehumidifiers Aren’t Effective When Using Wet Pad and Fan Systems Evaporative cooling, such as wet pad and fan systems, is common in greenhouses in warm regions. DG-6 North America Heating & Cooling Split.DG-12 North America Heating & Cooling Split.