Analysis Of The Building Exterior Wall Thermal Performance In-situ Detection Method

With the development of technology and social progress, the demand for energy is increasing in a state, thus saving energy for sustainable development of society plays a vital role. The proportion of building energy consumption in the total social energy consumption continues to increase in our country, so much more emphasis on building energy efficiency is paid. Since 2001 the state has promulgated a series of building energy efficiency standards and related regulations to ensure the progress of the building energy efficiency. Have energy conservation buildings erected one after another in recent years, testing of building energy-saving work has been around the corner. In building energy saving detection, envelope detection of heat transfer coefficient is very important.The existing detection methods of building envelope heat transfer coefficient was described in this paper, and concerning requirement of the on-site detection of plant and equipment, which was easy to carry, simple operation, easy to install, test results are accurate, then the heat flow meter method was selected to detect the conduction thermal resistance of external wall in a dormitory. By the comparison of measuring value and the designed value of the thermal resistance, the difference between the two was found out, and the analyzee the reasons for the differences and put forward the method of numerical simulation for wall heat conduction analysis. The the CFD software FLUENT was adopted to the following analysises: by the comparative analysis the simulation results with the calculated value in the case of steady and unsteady three-dimensional wall heat conduction process, to verify the feasibility of model; Then the measured data was used as the numerical simulation input parameters to do the numerical calculations of the testing wall in unsteady, and numerical values of the thermal resistance of the wall and testing the value and design value of the test were analyzed; Applied FLUENT to analysis one-dimensional heat conduction areas of the testing the wall, obtaining the areas in steady and unsteady state heat respectively, which would be useful for on-site detection of a reference layout of the measuring point; The calculating results of a typical day on the seasons results showed that using the arithmetic mean method to calculate the thermal resistance would get good accuracy when considering the cyclical nature of the outdoor temperature changes in the one-dimensional Non-state heat conduction problem; At last through the thermal performance analysis of the wall in transition seasons, the temperature difference was obtained for the in-situ detection in these seasons.