Application Analysis of Aluminum Foil and Phenolic Insulation Board

Why composite aluminum foil on the surface of phenolic insulation board? Why is this new material composed of aluminum foil and phenolic board so widely used in various thermal insulation systems? What application value does aluminum foil play?

This is to explain the effectiveness of this material from the perspective of architectural physics and thermal engineering.
As you know, there are three forms of heat transfer: convection, thermal conductivity and radiation. Based on these three forms of heat transfer, we have adopted a variety of targeted measures in building energy conservation.

The heat will flow with the flow of air. If the sealing is strengthened to reduce the flow, the heat convection will be reduced. Therefore, the external windows and walls of our buildings should have good airtightness.

Heat is transferred from one part of an object to another, and from this object to another, just like electricity. If the thermal resistance of such an object is very large, then there will be little transmission. Therefore, thermal insulation materials with high thermal resistance can block heat transfer.
However, the existence of radiation causes heat to spread. The most typical case is that the direct solar radiation and diffuse reflection (far-infrared radiation) in the air will still pass through the transparent glass.

Plating a layer of silver on the glass surface can effectively reflect the thermal radiation just like a mirror, which can better reduce the heat transfer
After the inner glass cavity surface is silvered, the indoor heat transfer to the outside can be reduced. This is a common practice in the North. Then, does it not have the same effect to cover a layer of metal aluminum foil on the surface of thermal insulation materials?
If there are only thermal insulation materials in the roof insulation structure, the proportion of heat transfer is still large

A layer of aluminum foil is used to reflect some heat.
Now you understand the benefits of using thermal insulation materials and aluminum foil layer together!