Frequency Method Based On Building Envelope Thermal Performance Scene Detection Technology

This paper puts forward a new idea of frequency characteristic method to test thermal performance of building envelope. Through simulation calculation and contrast analysis of different materials, drawing the frequency characteristic curve of a single homogeneous material, it proved that the frequency characteristic is the inherent characteristic of the material, and the frequency characteristic of the material can be used to detect the thermal performance of building envelope. Proof temperature affect the shape of the wave frequency characteristics can be ignored, which for outdoor temperature is not standard sine wave, but still can draw a standard frequency characteristics for thermal performance field testing envelopes provide a theoretical basis. Analysis of obtained amplitude-frequency characteristic curve is a curve of exponential function, phase-frequency characteristic curve is a graph of a polynomial function, their various coefficients have to do with the properties of the material of itself, and when the frequency characteristic coefficient values of M is more than 2.5, the frequency characteristics of the material data and the calculated fit function exactly. At the same time, comparing with the results of theoretical calculation, numerical simulation, field tests the calculation from engineering software get the conclusions, that have verified the frequency characteristic of accuracy and reliability of detection method for the thermal performance of building envelope is verified, the theoretical calculation formula needs to be further improved, and analysis of the causes leading to the building at the design stage of the building is not energy-efficient. By analyzing the thermal conductivity of the wall exhibited in the process of thermal performance, even if the walls come to the same theory thermally conductive heat resistance, actually, heat transfer process of wall exhibit differences in thermal performance, also have relationship with its arrangement of the layers of material, and proved building envelope thermal performance indicators can't be judged only by Thermal resistance or heat transfer coefficient, Also need to the Its attenuation and delay of the outdoor hot action as a co-judge to its thermal performance.