Aquaculture heat lamp-the principle of far infrared heating

Infrared light has a wavelength of 0.75μm to 1000μm, lying between electromagnetic waves and visible light. It travels as radiation. In industry, infrared light with a wavelength of 0.75μm to 1.5μm is called near-infrared, while that with a wavelength of 1.5μm to 1000μm is called far-infrared. Far-infrared, like visible light, ultraviolet light, and X-rays, is an electromagnetic wave, traveling at speeds of up to 300,000 kilometers per second. Its primary function is thermal energy.

The absorption spectrum of most organic matter and water falls between 2.5μm and 25μm. When the wavelength of the radiation source matches the absorption wavelength of the heated object, the substance readily absorbs infrared light. The wavelength of far-infrared light falls precisely within this range. When the heat source temperature is between 200°C and 727°C, over 80% of the total radiated energy is concentrated in the 2.5μm to 15μm range. Above 15μm, the energy increases by another 15% (200°C) to 4% (600°C), while the radiation energy above 250°C is even less. This shows that most of the energy in far-infrared radiation is easily absorbed by matter.

After absorbing infrared energy, molecules in matter can completely convert the energy of the photons into molecular vibrations, or rotational energy; this can also cause changes in the molecular rotational energy. Furthermore, the vibrational spectrum has a vibration-broadening and rotation-enhancing effect, increasing the amplitude around the equilibrium position and intensifying the internal vibrations. Because the movement of electrons and the vibration of molecules occur at extremely high speeds, this movement constantly causes the vibrations of the lattice and bond groups to collide with each other. This change in state of motion is like the accelerated friction between two rapidly moving objects, generating heat and temperature, resulting in a rapid temperature increase. Furthermore, when infrared radiation heats an object, the temperature at the site where the infrared radiation penetrates is often higher than the surface. For example, the internal temperature of corn kernels exposed to infrared radiation is 5°C-10°C higher than the surface temperature. Therefore, the items heated by infrared radiation during dehydration and drying are subject to the simultaneous action of a temperature gradient that is high inside and low outside, and a humidity gradient that continuously transfers the internal moisture out and diffuses and evaporates, achieving the purpose of rapid drying.