A New In-situ Test Method For Building Envelop Thermal Performance And Its Influence Factor Analysis

The energy problem has become a bottleneck restricting the development of our economy and affected our country economic sustainable and healthy development. The wall is the most important parts in the envelope of residential buildings. The capability of heat insulation and preservation plays a key role in building energy conservation. Detecting the thermal performance of building wall is the most important part. When we analysis the existing test methods for building envelop thermal performance, we find that these methods have its limitations. It is urgent need to develop a new test method for building envelop thermal performance.This paper introduces the theories of the existing test methods for building envelop thermal performance, such as heat flow meter method, hotbox method, the plane heat source method with constant power measurement, etc. The applicability, characteristics and merits of these existing building envelope detection methods are introduced in this thesis. Arithmetic mean method and dynamic analysis method are usually used data processing methods. These methods are introduced in this paper.This paper puts forward a new test method for building envelop thermal performance.The theory and component of this new test method are described in detail in this paper. When we use the hot-box to detect the thermal resistance of the enclosure structure, the building wall will in a specialness heat transfer state. This paper analyzes this specialness heat transfer state and simplifies the model of building wall heat conduction. This paper gives the computational formula of thermal resistance of the wall.According to the theory of the new test method, we made the detection equipment of building wall thermal resistance. The heating power of this equipment can be controlled. We can use this equipment to inquiry the influencing factors of in-situ test. This equipment can be used in different district.We build the basic model of this new test method for building envelop thermal performance by ANSYS 15.0.This ANSYS model can provide a theoretical support for the new test method. We can change the parameter setting of this model, such as hot-box area, hot-box heat transfer, the composition of enclosure structure and the disturbance in test sites. This paper explores these influencing factors by this ANSYS model.This paper inquiries the three-dimensionality of the heat transfer in building envelop and the attenuation phenomenon along the direction of heat transfer through a large number of computer simulation and field test data. This paper further puts forward the Hotbox- Two-sided-Heat flow meter method. When we detect the thermal resistance of XPS and building walls by the Hotbox-Two-sided-Heat flow meter method, we get the result of the high accuracy.