Misting for greenhouses: a simple and effective system
When shade awnings and air circulation are not enough, for cooling in agricultural greenhouses and nurseries it is necessary to use evaporative cooling, also known as a misting system. By means of a nebulization of cold steam obtained with special high-pressure nebulizer nozzles, an aerosol of extremely fine water molecules is produced. In contact with the hot air, the molecules evaporate, subtracting the energy necessary for the change of state from the surrounding air. In agrotechnics, the atomizers reduce the temperature according to the room air exchange capacity through the openings or ventilation where present
How greenhouse misting works
Evaporating water removes energy from the environment by increasing the relative humidity. Therefore misting systems are all the more effective the higher the temperatures and the lower the humidity levels. The cost of a greenhouse and nursery misting system is low-impact and is determined by a misting unit or pump, thin high-pressure piping lines and a network of uniformly distributed nozzles that spread the coolness everywhere. Simple or with advanced electronics, the systems can serve one or more structures, even with different parameter settings. Water is the most natural and least invasive cooling method with affordable costs for every need
High pressure water in greenhouses
In greenhouse misting, raising the pressure can consume much less water and produce an extremely fine mist that does not get wet. Contrary to what is believed, low pressure produces a much greater expenditure creating more inconveniences. However, if desired, it is also possible to spray it in order to imbibe the earth or create a dew on the plants. It all depends on how the system is designed and installed
Advantages
In addition to cooling or humidifying in a precise way, misting systems for greenhouses have an anti-mosquito and insect effect and allow the distribution of necessary substances which will deposit on the ground. Dissipatable substances must be premixed in water and be totally water soluble; not all of them can be nebulized and in any case with precise prescriptions from the manufacturer and the user of the device
Misting fans or misting nozzles?
The solution that uses misting fans has the advantage of cooling better and faster, reducing the amount of water dissipated. On the other hand, ventilation is not always compatible with some plants and/or crops that need still air without the transport of spores or pollen between various sectors. Nozzle-only atomisation is easier to install and distributes more cold vapor evenly. Both solutions are functional to different contexts of both horticultural and fruit and vegetable production. The system is particularly useful in the production of mushrooms, as it allows an extension of the production of more than a month
