 |
| |
|
|
|
|
|
|
(Your shopping cart is empty)
|
|
|
|
|
Thermo Reflectance and Emissivity:
The geometrical micro fiber structure and high diffuse reflection of ORCA Grow Film® lends itself to be a natural insulator and exhibit a low emissivity. ORCA Grow Film® remains highly reflective at wavelengths out past 700nm.
The emissivity of a material (usually written ε or e) is the relative power of its surface to emit heat by radiation. It is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature. It is a measure of a material's ability to radiate absorbed energy. Emissivity is a dimensionless quantity, so it does not have units.
In general, the duller and blacker a material is, the closer its emissivity is to 1. The more reflective a material is, the lower its emissivity. Emissivity depends on factors such as temperature, emission angle, and wavelength.
Although it is common to discuss the "emissivity of a material", the emissivity of a material does in general depend on its thickness. The emissivities quoted for materials are for samples of infinite thickness (which, in practice, means samples which are optically thick) — thinner samples of material will have reduced emissivity.
When dealing with non-black surfaces, the deviations from ideal black body behavior are determined by both the geometrical structure and the chemical composition, and follow Kirchhoff's law of thermal radiation: emissivity equals absorptivity (for an object in thermal equilibrium), so that an object that does not absorb all incident light will also emit less radiation than an ideal black body.
|
|
|
|
|
|
|
|
|
