When the air temperature difference between the two sides is 1K( 1℃), the heat transferred per square meter of wall area in unit time is W/(M2. k)。 That is to say, the heat transfer coefficient k includes all structural levels of the wall and the air boundary layer on both sides. It represents the thermal performance of the wall insulation system. Some studies show that the reduction of the heat transfer coefficient of the external wall will obviously reduce the building energy consumption.
Extended data:
Heat flow meter method:
The basic idea of heat flow meter method is to measure the heat flow through the measured wall and the temperature on both sides of the wall at the same time, so as to calculate the thermal resistance and heat transfer coefficient of the measured wall.
The probe of heat flow meter is made according to thermoelectric effect and temperature gradient principle. A thermopile is buried in the probe. When a certain heat flow Q flows vertically through the probe, there is a certain temperature difference △T between the two sides of the substrate, which makes the thermopile installed in the substrate generate a certain electromotive force.
Its heat flux density is directly proportional to the temperature difference △T between the two sides of the probe and the generated electromotive force. The most fundamental requirement of the heat flow meter method is that the heat flow through the heat flow meter is not only through the measured object, but also parallel to the temperature gradient direction, that is, the heat flow through the heat flow meter is steady one-dimensional conduction, regardless of the surrounding diffusion.
Baidu encyclopedia -K value