Misting System

Misting systems that operate at up to 250psi, produce a droplet size of 10 to 20 times that of a High Pressure Fogging System (i.e. 100 to 200 micron) and these droplets are too heavy to be suspended in the air. The increased droplet size leads to poor evaporation, reduced greenhouse cooling effectiveness and significant wetness in the greenhouse. The wetness on the foliage can cause increased disease, fruit damage and general wetness can pose a safety risk to greenhouse staff.

Fogging System

High Pressure Fogging which operates at over 700psi produces droplets as small as 10 micron which gives optimal greenhouse cooling and temperature control. At this size the droplets flash evaporate, eliminating the chance for excess wetness to occur and cooling the greenhouse. As this cooling is happening in the area where the heat is, the cool air travels down to the crop level, to be replaced by the hot air rising. The convection air currents ensure even temperature distribution throughout the crop without the need for fans to stir and distribute the cooler air around the greenhouse

Cooling

With droplets as fine as 10 microns, fog “flash evaporates” so that cooling is achieved with out wetness accumulating on the floors, plants, equipment and people. Because the droplets fully evaporate high pressure fogging is often referred to as dry fog. One of the advantages of high pressure fogging is that it is applied directly where the hot air is located. The hot air in the top of the greenhouse is cooled and then drops to the crop level, to be replaced by hot air rising. This continuous natural convection ensures even distribution of the cooled air over the crop without any further circulation being required through extra mechanical assistance. Careful balancing of the system for both droplet size (through pressure adjustment) and cycling of the system ensures that cooling is achieved without wetting the crop. The Mistafog system is based on achieving maximum atomisation of the water and hence evaporation, but with minimum water flow. Greenhouse misting systems bring dramatic cooling effects using the power of evaporative cooling, the process of evaporation actually using heat from the air.

Special Effects

Special Effects misting and fogging is a highly specialised craft whereby the atomised water droplets are sprayed into the air to create a visually attractive, attention grabbing display. The mist or fog could be emitted from the ground through nozzles that are mounted underground, through gardens and landscaping to give a misty tropical effect with the mist and fog drifting through the landscape features, or from structures that are either existing or specifically built for the purpose. The drifting mist tends to capture the attention of the people in the surrounding area and either draw them to the feature or at least hold their attention during the display. Often people and in particular children, will want to interact with the fog display, running through it to either hide or play in the mist cloud that has been created. With the fine atomisation created by the high pressure fogging system, people can stand close the the special effects or interact with the display without getting wet.

Humidity

Ideal humidity in greenhouses should be between 50% and 70% for ideal growing conditions, however much higher levels are achievable if required, such as in propagation nurseries. When heat goes up, humidity levels drop. The already stressed plants face double trouble, and it can be a deadly combination. High pressure fogging or misting system can provide almost immediate humidification, overcoming a potential huge loss in greenhouses. Mushrooms contain around 90% water. Since there is no barrier between the mushroom surface and the air, mushrooms lose water and weight very quickly in humidity below 90%. Accurate humidity and temperature control is essential throughout the stages of mushroom production. Compost must be moist, but without wetness. Spawning requires high humidity – and high temperature. High humidity is especially crucial during pinning, when watering is not advised.

Dust Control

Dust is an ever increasing environmental problem. High pressure fogging produces small droplets or a misting system will produce slightly larger droplets and this is the determining feature that makes it so effective. When water droplets sprayed to control dust are too large, the dust particles flow around the droplets, and are not absorbed. If the droplet diameter is much greater than the dust particle, the dust particle simply follows the airstream lines around the droplet, and little or no contact occurs.