Humidifier
A humidifier is a household appliance or device designed to increase the moisture level in the air within a room or an enclosed space.
For example, a typical modern apartment of 50 m2 (540 sq ft) with closed windows (wood isolation) may consume 36.72 litres per day (9.70 U.S. gallons per day) to raise the relative humidity from 20% to 55%: 24 * 1,53 L/h (2*1×125×1.2×0.0051): Low humidity may occur in hot, dry desert climates, or indoors in artificially heated spaces.
Industrial humidifiers are used when a specific humidity level must be maintained to prevent static electricity buildup, preserve material properties, and ensure a comfortable and healthy environment for workers or residents.
Static problems are prevalent in industries such as packaging, printing, paper, plastics, textiles, electronics, automotive manufacturing and pharmaceuticals.
[11] The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) has traditionally recommended a range of 45–55% RH in data centers to prevent sparks that can damage IT equipment.
Humidifiers are needed in cold storage rooms to preserve the freshness of food against the dryness caused by hot temperatures.
[13] Natural humidifiers don't use or need a demineralization filter because the water is slowly evaporated which leaves the mineral deposit at the bottom of the container.
One version of a natural humidifier uses a stainless steel bowl, partially filled with water, covered by a towel.
The wick is made of a porous material that absorbs water from the reservoir and provides a larger surface area for it to evaporate from.
Therefore, this type of humidifier is partially self-regulating; as the humidity of the room increases, the water vapor output naturally decreases.
Ultrasonic humidifiers use a piezoelectric transducer to create a high frequency (1-2 MHz[15]) mechanical oscillation in a film of water.
This forms an extremely fine mist of droplets about one micron in diameter, that is quickly evaporated into the air flow.
Special disposable demineralization cartridges may also reduce the amount of airborne material, but the EPA warns, "the ability of these devices to remove minerals may vary widely.
Vaporizers may be healthier than cool mist types of humidifiers because steam is less likely to convey mineral impurities or microorganisms from the standing water in the reservoir.
The heat source in poorly designed humidifiers can overheat, causing the product to melt, leak, and start fires.
Ultrasonic wave nebulizers trap the mineral deposits over time, even if filters are used, and require cleaning with vinegar or citric acid to control buildup.
Most models with heating elements come with replacement demineralization filters (cartridges, or plastic foam, for the tank, and fabric near the heater in the reservoir) to reduce the amount of minerals entering the system.
A manual way to figure out if a filter is clogged is to shake it, if the content of it (even if wet) doesn't move around, then it's unlikely that sufficient water will pass through.
In colder months, they may provide modest energy savings, since as humidity increases, occupants may feel warm at a lower temperature.
When the hygrostat calls for humidity, the motor is turned on causing the drum to rotate slowly through the pan of water and preventing the foam pad from drying out.
For the latter reason especially, drum-style humidifiers should always be turned off at the water supply during summer (air conditioning) months, and should always be used with high quality furnace air filters (MERV ratings as high as possible to ensure small numbers of mold spores reaching the humidifier pan) when the water supply is turned on.
The "biscuit" has a coating of a matte ceramic, resulting in an extremely large surface area within a small space.
[20] Additional types include non-bypass flow-through (fan augmented), steam, impeller or centrifugal atomizer, and under duct designs.
From 2006 to 2011, the disinfectant polyhexamethylene guanidine and other toxic materials were used as a cleaning agent for humidifier water tanks in Korea, leading to severe lung disease.
