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An infrared heater or heat lamp is a heating appliance containing a high-temperature emitter that transfers energy to a cooler object through electromagnetic radiation. Depending on the temperature of the emitter, the wavelength of the peak of the infrared radiation ranges from 750 nm to 1 mm.
Infrared heating uses infrared lamps, commonly called heat lamps, to transmit infrared radiation to the body that is being heated. When a body with a large surface area needs to be heated, an array of infrared lamps is often used. The lamp commonly contains an incandescent bulb that produces infrared radiation.
The cellular structure of the vegetation then causes this infrared light to be reflected because each cell acts something like an elementary corner reflector. [citation needed] The change can be from 5% to 50% reflectance going from 680 nm to 730 nm. This is an advantage to plants in avoiding overheating during photosynthesis.
For a tungsten filament at a typical temperature of 3000 K, only a small fraction of the emitted radiation is visible, and the majority is infrared light. This infrared light does not help a person see, but still transfers heat to the environment, making incandescent lights relatively inefficient as a light source. [25]
Infrared communications are useful for indoor use in areas of high population density. IR does not penetrate walls and so does not interfere with other devices in adjoining rooms. Infrared is the most common way for remote controls to command appliances. Infrared remote control protocols like RC-5, SIRC, are used to communicate with infrared.
Radiation reaching a plant contains entropy as well as energy, and combining those two concepts the exergy can be determined. This sort of analysis is known as exergy analysis or second law analysis, and the exergy represents a measure of the useful work, i.e., the useful part of radiation which can be transformed into other forms of energy.
It can also be used to heat a stream of gas that is used for measurement or instrumentation. Space heating is a good substitution when heat is required but traditional means, such as electricity or safety concerns over explosive gas, cannot be used. Catalytic space heaters generate infrared heat to raise the temperature in a given area. [2]
The movement of heat embodied in water vapour as it leaves vegetation is not well understood given the complexity of the dynamics. [11] While the movement of water into the atmosphere through evapotranspiration and consequent cooling is broadly accepted, the movement of water further into the atmosphere is more contentious. [12]