Heating Tube

Infrared heat is the most basic form of heating and is the direct transfer of heat from a heater to an object or material without heating the air. The type of heat produced by an heating tube is the same as environmental heat from the sun.
In an heating tube, panels are heated until they get hot enough to emit infrared radiation that continually travels until it meets a solid object or workpiece. It is a direct heat transfer process that is similar to the transfer of heat between metals, coils, and materials using radiant waves.
With traditional heating, the air in an environment is heated before any objects will feel the increase in temperature. Heating tubes are designed to project heat to warm objects directly and not change the temperature in a space. Aside from their ability to rapidly raise the temperature of objects or materials, heating tubes complete the heating process using a minimal amount of energy at lower cost.

Electromagnetic waves
Electromagnetic waves are composed of waves that oscillate perpendicular to each other. One of the waves is an electric field, while the other is a magnetic field.
Electromagnetic waves are described by wavelength and frequency, with wavelengths being the distance between adjacent crests in the cycle of a wave. In the electromagnetic spectrum, wavelengths are usually expressed in nanometers or angstroms. Frequency is the number of wave cycles per second, which is expressed in hertz (HZ), which is used to classify electromagnetic waves.
Wavelength and frequency are inversely related to each other. The energy of a wave is directly proportional to the frequency but inversely proportional to the wavelength. Waves with higher frequencies and shorter wavelengths carry higher energy and are more transmissive. Waves with lower frequencies and longer wavelengths carry less energy.
Unlike mechanical waves, electromagnetic waves do not require a medium to generate. Sound waves or mechanical waves move through the air and do not need surrounding molecules to move through the air, objects, or even a vacuum. It is the reason it is possible to feel the warmth of the sun, though it is thousands of miles away from the earth, as well as the surrounding cold air, when we stay under the sun. This principle is also applied in the operation of heating tubes, which are comparable to the sun.
Infrared waves
The infrared region is between the visible and the microwave regions of the electromagnetic spectrum. Infrared waves have a wavelength ranging from 700 nm (430 thz) – 1 mm (300 ghz).

Radiative heat transfer
Radiation is the mechanism of heat transfer caused by the emission, absorption, and reflection of electromagnetic waves of bodies. All bodies above the absolute temperature (-459.4°F or -273°C) emit thermal radiation. The release of thermal radiation is caused by random movements, vibrations, and collisions of atoms and molecules and their constituting protons and electrons.
Various types of materials, items, and objects radiate heat based on their temperature. As they get hotter, these objects radiate thermal energy that is transferred by radiation but does not affect the surrounding molecules. Thermal energy easily travels through the air, objects, and even a vacuum and is independent of the amount of radiation emitted by a receiving material. Other factors affecting radiation are the nature of the surface and the angle of incident radiation.
Conduction and convection are other mechanisms of heat transfer that can happen simultaneously with radiation. In conduction, heat is transmitted through collisions and vibrations between neighboring atoms or molecules that readily occur in solids. The direction of heat transfer in conduction is from a region of higher kinetic energy to a region of lower kinetic energy.
In convection, thermal energy is transferred through the displacement of molecules in a bulk fluid. When a portion of the fluid is heated, the molecules closest to the primary heat source expand and travel away from it. Thermal energy is carried along with the molecules' movement and is transferred to a cooler portion of the fluid mass.