humidifier
A humidifier (colloquially humidifier ) is mostly a technical device to increase the humidity . A distinction is made between smaller devices with a water tank for installation in the room and devices with a permanent connection to a water pipe , for example for installation in central ventilation systems .
purpose
Especially in the heating season, the relative humidity often falls below the recommended range of 40% RH for living and working spaces (see also comfort ). This low humidity has an unfavorable effect on the well-being of people and animals and can also promote diseases of the respiratory system if the room air is permanently very dry . Respiratory diseases, voice disorders, eye irritation, skin diseases and other symptoms can be favored by air that is too dry . The dehydration can also be harmful to furniture, wooden floors, antiques or musical instruments. This effect can be counteracted by using air humidifiers. With the use of air humidifiers, however, the demands on hygiene increase, since microorganisms or germs are promoted as the humidity increases .
Sometimes the opposite effect, i.e. lowering the air humidity, is desirable, for example in museums , in order to slow down the aging of paintings and other exhibits. To this end, dehumidifier or combined air conditioners used.
A distinction must be made between devices for room air humidification in medicine and care. There it is about the humidification of the breathing air of artificially ventilated persons to protect the mucous membranes .
Types
Steam humidifier
Steam humidifiers, also called evaporators , bring water to the boil and release the steam into the room air. Its main features are:
- high energy consumption ,
- high humidification performance,
- hygienic, because the evaporation kills any germs in the water ,
- Risk of condensation in the case of an unfavorable installation and a cool environment,
- If there is a high lime content in the water: Danger of lime deposits in the device, maintenance costs,
- Danger from respirable aerosols in the case of insufficient heating ( legionellosis ),
- If there is calcification, there is a risk that the water will no longer be heated sufficiently and that bacteria will develop,
- Risk of overhumidification, regulation necessary as well
- Risk of scalding from escaping steam.
There are two different designs:
- The electrode vaporizer has two electrodes directly in the water tank , between which a current flows through the water. This heats the water between the electrodes to the boiling point. These devices cannot be operated with distilled or demineralized water because it lacks the necessary electrical conductivity .
- With the heating element evaporator, water is fed from a storage tank or a drinking water pipe into an evaporation chamber. There is an electrical heating element that works like a stove top . The current flows through a heating coil . Some devices have a cover made of non-stick material to make cleaning easier. Devices of this type can be operated with distilled water in order to avoid the deposition of minerals. The steam passes through a hose to a steam lance , which is built into the ventilation duct and emits large quantities of water vapor into the flowing air.
Evaporator
Evaporators distribute the water over the largest possible surface using filter mats or rotating lamellas, and can optionally also blow a stream of air over it. Features are:
- low energy consumption,
- Medium to low humidification output - but large models sometimes have outputs of 20 to 30 liters per day and are therefore also suitable for larger rooms and open structures.
- Lowering the air temperature ( adiabatic cooling )
- no aerosol formation
- natural regulation of room humidity, no overhumidification
- requires regular cleaning or addition of disinfectant to the water (with UVC disinfection, i.e. disinfection via ultraviolet rays is not required)
Evaporators work passively by placing a container with water, e.g. B. is attached to a radiator. The evaporation rate is low. A wet towel on the heater and a room fountain also work according to this principle. The water in the evaporator can easily become contaminated, as the germs present in the water can multiply quickly in the warm environment. However, the air cannot be contaminated because no aerosols are formed.
Atomizer
In older atomizers, water sucked in from a storage vessel was thrown from the edge of a rapidly rotating disk against a fine sieve and the resulting water mist was then blown into the room through fan blades attached to the rotating disk. Modern atomizers, on the other hand, use ultrasound or pressure pumps with fine nozzles to atomize the water into tiny droplets, which can optionally be blown into the room with a fan. Their characteristics are:
- low energy consumption,
- Lowering the air temperature (through adiabatic cooling)
- Possibility of condensate and lime deposits in the vicinity of the device if the setting is incorrect or the lime content of the water is too high,
- Possibility of germ contamination of the mist (e.g. Legionella ) when feeding from storage tanks with too high a water temperature or insufficiently maintained hot water pipes
- Requirement of regular and careful cleaning of storage containers.
Alternatives
In addition to these technical solutions, indoor plants - especially those with a high water consumption such as. B. the green lily - improve the indoor climate and even purify the air. However, this effect is relatively limited in larger rooms or with very low room humidity, since the transpiration of the plants alone is hardly sufficient to give off the required amounts of water. In addition, the use of diffusion-open building materials with a certain storage capacity for moisture while making the building windproof can reduce fluctuations in humidity. Modern low-temperature heating also causes less dehydration.
See also
literature
- Fraunhofer Information Center for Space and Building (IRB): Indoor climate at the workplace . [Ed.] 2007. ISBN 978-3-81-672392-9 .
- Michael Busch: Compendium of Occupational Medicine . 2004. ISBN 3-000-13046-2 .
- P. Hupfer, W. Kuttler: Weather and climate . Teubner Verlag, Stuttgart / Leipzig 1998. ISBN 3-322-00255-1 .
