How infrared works

Imagine, you have been skiing, sitting on the patio in the sun. You are enjoying the enveloping warmth. At the same time, it’s freezing. This is possible thanks to the way in which the sun’s infrared rays work. When infrared rays touch a surface, energy is released in the form of heat.

Infrared radiation is a natural and important source of heat transferal. An obvious example is the sun. The sun produces an enormous amount of energy through nuclear fission. The sun radiates this energy in various wavelengths including the form of ultra-violet rays, visible light and infrared radiation. After a journey through space of approximately 8 minutes at a speed of 1,080,000,000 km/h, the sun’s rays reach the earth’s surface. During the day, the earth’s surface is heated by the infrared part of the sun’s rays. At night, the earth cools off again by releasing the heat in the form of infrared radiation. This is a natural process which is not harmful to humans. In theory, every object with a temperature over the absolute zero point radiates heat rays. The intensity of the radiation increases as the vibration of the atoms in the object increases.

The shorter the wave lengths, the greater the energy content of the radiation. Infrared radiation consists of electromagnetic waves with a length of 0.75 to 1000 μm. When infrared rays fall onto a surface, the radiation energy is absorbed by surface atoms regardless of the air temperature.

Heat Transfer

According to the first law of thermodynamics, heat always flows from a high-temperature object to a low-temperature object.  This heat transfer can be in the form of conduction, convection or radiation. The driving force in this process is the temperature difference. The mechanisms for the transfer of heat, conduction, convection or radiation, can be applied to heating a space.     

Conduction;

Material is used as the transport medium. For instance the cooking pan: The bottom of the pan is heated by a gas flame, or electric element, and the heat is then conducted to the inside of the pan.

Convection:

In most cases of convection the air is used as a medium for heat transport. This particular way of heating is widely used in residential and commercial applications worldwide. This can be a hot air/forced air system, such as used throughout North America, or a water/steam-based system whereby a radiator heats the air - - warm air that rises to the ceiling and cold air pulled through the return ducting or radiator base, where it is heated, creating an airflow which heats the entire space.

In contrast with conduction or convection, heat transfer by means of radiation does not require an intermediate material. That is why, in the case of infrared radiation, the heat is released primarily to objects and secondarily to the ambient air. In principle, infrared heating combines two separate heating mechanisms, namely heating as a result of radiation and heating as a consequence of the ‘insulating’ effect of the ambient air.

Radiation:

Far-infrared Heating is considered to be one of the safest ways to heat people, animals and objects. It requires no medium to transport warmth. When the Far-infrared waves (invisible light) collides with (or is absorbed by) surfaces, including the human body, warmth is generated.  This is also known as “direct” heating or the same sort of heating we experience through the sun.

Radiation and insulation work together

For example, as soon as an Infrared heat-source located in a cold place (say 32 degrees Fahrenheit or 0 degrees Celsius) is switched on, the radiation intensity is at a maximum and the air temperature is minimal.   As the objects heat up, the air temperature gradually increases and the radiation’s intensity will gradually decrease.  After a while, the air in the space will have reached a temperature of 68°F for example. At this point, the intensity of both the air temperature and the heating medium now remain constant. This means that equilibrium has been established since the combination of both of these heating mechanisms (air and infrared waves) provides a comfortable climate. This climate can be compared with a normal (convection) air temperature of approx. 72°F. The advantage of this is that people feel comfortable more quickly at a relatively low temperatures compared with convection (hot air) heating.