Let's Get Scientific


How it Works - The Science Behind Eco Heat Heaters

Electromagnetic Radiation and Wavelength

Electromagnetic radiation is classified into several types according to the frequency of its wave; these types include (in order of increasing frequency and decreasing wavelength):
  • Radio Waves,
  • Microwaves,
  • Terahertz Radiation,
  • Infrared Radiation,
  • Visible Light,
  • Ultraviolet Radiation,
  • X-rays
  • Gamma Rays
A small window of frequencies are sensed by human eyes; this is what we call the visible spectrum, or light.
Light Spectrum
Because all electromagnetic waves travel at the speed of light, the behaviour of electromagnetic radiation depends on its wavelength. Higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths. This is depicted by the formula:
v = f x λ (speed = frequency x wavelength)
Light and electromagnetic waves of any frequency will heat surfaces that absorb them. 

Temperature and Wavelength

Every object in the universe that has a temperature gives off electromagnetic radiation. Its electromagnetic waves will peak at a specific wavelength, depending on its source and temperature, and no object gives off all wavelengths equally.  
The emitted wave frequency of the thermal radiation is a probability distribution depending only on temperature, and for a genuine black body is described by Planck’s law of radiation. Wien's law gives the most likely frequency of the emitted radiation, and the Stefan–Boltzmann law describes the heat intensity.
Wavelength and Temperature Diagram
If the object is a black body, the radiation is termed black-body radiation.
The graph on the right uses Planck’s law to determine the different wavelengths at a set temperature (y-axis is Watt / area / wavelength). This graph shows that black bodies give off electromagnetic waves at wavelengths of the electromagnetic spectrum, but not equally at all wavelengths. The peak wavelength is derived from the temperature of the black body using Wien’s displacement law.
Wien’s displacement law states that there is an inverse relationship between the wavelength of the peak emission and the back body’s temperature, i.e. the hotter the object, the shorter the wave length and vice versa.
At room temperature, black bodies emit mostly infrared light, but as the temperature increases past a few hundred degrees Celsius, black bodies start to emit visible wavelengths, from red through orange, yellow and white before ending up at blue, beyond which the emission includes increasing amounts of ultraviolet if it is heated to extreme temperatures. 

Radiation from a human body

The total surface area of an adult is about 2 m², and the mid- and far-infrared emissivity of skin and most clothing is near unity, as it is for most nonmetallic surfaces.
Radiation from a human account for about 2/3 of thermal energy loss in cool, still air.
Humans at normal body temperature radiate chiefly at wavelengths around 10µm (micrometers) at 37.0 °C. 

Eco Heat Heaters

Our heaters operate in an infrared band that is ideal for absorption by a human body.
Our heaters are energy efficient because:
  • they focus on warming human bodies and not the ambient temperature.
  • the elements function at a relatively low temperature, consuming less energy. 

References

Wiki – Black Body
Wiki – Emissivity
Wiki – Heat Conduction  
Wiki – Heat Lamp  
Wiki – Infrared
Wiki – Infrared Heater  
Wiki – Radiation
Wiki – Planck’s Law 
Wiki – Speed of Light
Wiki – Stefan-Boltzmann Law   
Wiki – Thermal Radiation