What Is a Misting System?
A misting system refers to the process of spraying a fine mist of water over an open or indoor space to cool the surrounding air by the heat of vaporization as it evaporates.
The cooling effect is a gentle, cool sensation with a decrease in ambient temperature of about 3 to 5°C.
Water mist can be made in several ways: by increasing pressure with a mist pump and spraying it from a nozzle; by using the pressure of the water supply to blow it out of a nozzle; and by using high-pressure air to make a fine mist.
A misting system is also used to create a simple misting system using a manual pump from a bottle, or using a high-pressure gas sealed in a bottle.
Uses of Misting Systems
Misting systems are used in a wide range of fields, from household use to commercial use.
For home use, many of them are simple devices that use water pressure to generate mist. They are connected to a water hose in a garden, etc., and are suitable for children’s water play and for preventing extreme heat in the garden.
They can also be installed under eaves or on balconies to reduce the cooling load on the house. Using a small amount of water, it is possible to prevent extreme heat without using electricity.
In addition, by installing misting systems on the outdoor unit of an air conditioner to reduce power consumption, it can contribute to energy conservation during times of power shortages.
For commercial use, it is expected to be effective in preventing heat stroke in outdoor spaces. It can be used at event venues, driving ranges, construction sites, station platforms, station waiting areas, bus stops, airport corridors, zoos, department store rooftops, urban sidewalks, and many other locations.
Misting systems can be used not only outdoors, but also in large indoor areas. It is used in spaces that generate heat, such as cleaning factories, linen supply plants, paint shops, sheet metal shops, and machine shops, as well as in large spaces such as bookbinding and printing plants, automobile plants, vehicle depots, and gymnasiums.
When cooling indoor spaces, in addition to the cool misting systems, a ventilation system is required to control the rise in humidity.
Principle of Misting System
The cool misting systems uses the heat of vaporization of water to lower the ambient temperature. The heat of vaporization of water is 584 kcal per gram of water, and a small amount of water can produce a large cooling effect.
The key is how to make water evaporate efficiently and quickly. One method used is to blow water out through a nozzle to form fine particles.
Nozzles are used in the one-fluid method, which uses high-pressure water, and the two-fluid method, which also uses air pressure. If a pump is used to raise the water pressure to 4 MPa or higher, the average particle size of the mist will be 20 to 30 microns. If compressed air from an air compressor is used, the average particle size will be less than 10 microns.
The smaller the mist particle size is, the less water droplets are felt when they hit the human body, and the faster the evaporation speed is, the greater the cooling effect.
Features of Misting Systemd
It can be used for cooling in summer to prevent heat stroke, and as a humidification device in winter when it is dry, all year round.
It has the feature that products and workers hardly get wet. By reducing the mist particle size to 15μ or smaller and using a ventilation fan, the humidity rise is controlled and wetting is prevented.
This equipment has low running costs. Only the mist pump and ventilation fan require electricity, making this cooling device much cheaper in terms of electricity and equipment costs compared to cooling devices.
The misting systems has deodorizing effect. Tests using isovaleric acid, which is a component of perspiration odor, show that the odor intensity decreases immediately after use, and the cool feeling is maintained for more than 30 minutes after use.
The combination of ethanol and antibacterial ingredients produces a high bactericidal effect. It is used in spray-type misting systems.
How to Use Misting Systems
When used in outdoor spaces, it is effective to place the air outlets so that they surround the space to be cooled.
Generally, the outlet should be placed at a height of 2.5 to 3 meters above the ground. For short periods of time, such as for events, portable mobile or stand-type misting systems are also available.
When used indoors, such as in a factory, it is important to provide good ventilation to reduce the rise in humidity. Because cool misting systems evaporate small amounts of water, they have the disadvantage of increasing humidity in enclosed spaces. Ventilating and expelling the water vapor will reduce indoor temperatures and provide a very economical solution to extreme heat.
When used in homes and offices, consideration should be given to avoiding prolonged use at maximum mist volume and to installing the equipment away from computers and other electronic devices. This is because the indoor humidity rises and condensation occurs, which may cause mold and equipment malfunction.