Misting and Fogging
Make the task of managing your Cooling easier with Mistafog Fogging & Misting Systems
Fogging systems and misting systems are a cost effective and versatile way of controlling temperature, humidity and dust, in your greenhouse, warehouse, storage facility, quarry, recycling centre (MRF), farm, propagation nursery, or even your outdoor entertainment area.
Fogging systems and misting systems are often confused with each other as they are substantially the same. The difference between misting and fogging systems being in the size of the droplet they produce. Misting systems typically operate between 100psi and 250psi, with low pressure lines and nozzles. Misting normally produces droplets around 200 microns in size. Because of its size the droplet will drop to the floor relatively quickly and may cause wetness. High pressure fogging produces a droplet so fine (around 10 microns) that it is able to remain suspended in the air until it evaporates. The size of the fogging droplet also makes it ideal in dusty situations, to bond with dust particles to prevent dust escaping and or being inhaled.
Fogging systems are the most effective and uniform method of greenhouse cooling and can achieve temperature drops up to 10oC in unshaded and 15oC in shaded greenhouses. High Pressure Fogging Systems produce very small droplets of water of around 10 microns, which are suspended in the air and evaporate before they fall onto the crop.
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.
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
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.
Ideal humidity 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 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 is an ever increasing environmental problem. High pressure fogging produces small 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.