Radiant heating

A radiant heating or heat wave heater is a heater whose vast heat is transferred by thermal radiation. There are two fundamentally different types of construction, the high temperature radiators and the low- temperature radiator.

• 3.1 Electrical operation 3.1.1 Infrared heaters

Generally

Application

The principle of operation (heating by radiant heat energy) can be explained in comparison to convection heating, which uses, for the most part the room air as a heat carrier and heated it. In the radiation heating the heat energy is transferred directly through heat radiation, it operates in the absence of transmission media (vacuum). The transition from the radiant heater to the convection heating is gradual, since a radiation heating on the hot components, the heated air, and a convection heater and emits thermal radiation.

Advantages of radiant heating in the living area are the lower room air temperature (at the same subjective thermal sensation of the occupants ) and the reduced air circulation, which usually leads to a more comfortable indoor climate (less dry air) and less dust pollution. In case of unfavorable air flow conditions ( foot traffic areas, high ceilings ) is the radiation heating alone application reasons the heater of choice. Further advantages arise from the almost immediately available after turning heat. Thus, spaces that are rarely or only briefly used little or not remain heated and can be used when entering nevertheless with some comfort.

By reducing the transport of energy by means of heated air also caused thereby energy losses (ventilation, leaks ) reduce.

Physics

The physically correct expressed active principle of radiant heating - based on the proportion of radiation - the radiation exchange of the radiator with its environment. For very small area compared to the surrounding high temperature radiators, the retroactive effect of the environment can be neglected on the radiator. According to the Stefan- Boltzmann law, the radiated power is approximately a function of the fourth power of the temperature. At higher temperatures ( red to yellow glowing parts ) of the radiation component is large and can be set up and bundle by optical reflectors. Thus, the usable exergy of the system is higher than that of convection and heat conduction.

Low temperature radiators

Low temperature lamps are usually radiator is emitted on the other produced or stored thermal energy. The transmission medium is usually water, which flows through the radiator through pipelines, but also electric heating mats for smaller applications ( Badtemperierung ) are available. As usual designs floor, wall, ceiling heating systems ( metal, GK- and clay - Quick components ) are made ​​up on the market, but there are also special designs ( eg component heating) for special requirements.

Radiant heaters need due to their principle of a much larger room-side radiating as a convector. You can raumbegrenzende components may be integrated (advantage: no own footprint - disadvantage: poor maintainability ) or as flat components on a wall or ceiling applied be (advantage: easy maintenance - Drawback: walls: possible elimination of parking space).

High temperature radiators

In the high- temperature radiators, the heating on or in Abstrahlbauteil is generated and transmitted at high temperature. This heater form is used to deliver heat energy over a larger distance, or to a greater extent. Examples are

• Electric heater, for example Badzusatzheizung and changing table warmer, and
• Gas heater, for example, the catalytic Bauheizer, patio heater ( in everyday language also called patio heater ) and the industrial hall workplace heating.

The high temperature is at least a risk of burns, usually even a fire, by appropriate precautions (shielding, mounting outside the work area, distances to other objects ) must be met.

Electrical operation

In a radiant heating, a through by electric current heating coil or heating element is heated and radiates heat thus in the form of infrared rays. Behind the incandescent body is a mirror which directs the infrared radiation in one direction. Since the mantle of several hundred degrees Celsius is hot, a contact protection is always appropriate. The mantle is structurally one to a ceramic core for insulation wound against short circuit heating coil. The heating coil of the mantle is called the filament.

Today, infrared radiant heaters are used in many fields, such as in catering and in the private sector as an outdoor heating, additional heating in bathrooms and wherever heat is needed in the short term. Special changing radiant heaters are designed for the winding course of babies, mostly these are designed with 600 W heating power and with splinter protection (because quartz heating element ). Newer devices have an automatic cut-out (usually after 10 or 20 minutes of heating).

A special form of radiant electric heater is the infra-red lamp, in which the thermal energy generated through the filament is high enough to act medically from smaller distance can. But again, can not be ruled a fire hazard ( unobserved material contact during irradiation ).

An important special form of radiant electric heater is the bulb. In this design, even the largest part of the energy used to heat radiation is converted. A compared to other types of high, however overall still small part of the radiation (approx. 5% of the energy used ), however, emits in the visible region of the spectrum. This is achieved by the filament is enclosed in a protective gas, which allows higher temperatures of the mantle.

Infrared heaters

• See infrared radiators

References

• A. Kollmar and W. Liese: The radiant heating. 4th edition. R. Oldenbourg, München 1957.
• Bernd luck: radiant heating - theory and practice. Publisher of Construction, Berlin / CF Müller Verlag, Karlsruhe, 1982, ISBN 3-7880-7157-5. statements online