Research On Air Humidity Affecting Heat Transfer Of Thin Air Layer Of Thermal Insulation Wall Of Building

With the gradual of urbanization construction, a sharp rise in the number of buildings in our country, the resulting building energy consumption has already become the mainstay of the national energy consumption. Construction industry overall energy saving is imperative, therefore, to the final "twelfth five-year plan", China’s building energy efficiency to form 116 million tons of standard coal energy saving ability. By 2015, the northern cold and cold, hot summer and cold winter region comprehensively implement the new energy-saving design standards, implement the proportion of 95% or more, new buildings in cities and towns energy efficiency compared with the "eleventh five-year plan", increase more than 30%.Paper to aluminum alloy polyurethane integration of exterior wall thermal insulation decoration system as experimental object, select a typical building in Hefei area as the experimental base, design experiment plan, installation testing instrument for data collection, data gathering time contains two 2013 and 2014 year, a total of two complete experimental period of four quarters. Acquisition of physical parameters including composite insulation wall layers wall temperature, indoor and outdoor temperature, the air layer between the temperature, the air layer between the humidity, the air layer between the air velocity, wall heat flux and the layer.By analysis of variance, there is some correlation with the experimental data of the air layer between the temperature, humidity and wall heat flux. Acquisition of the air layer between the size of the air velocity in the heat integration system under the flow velocity is almost zero, there must is no convection heat transfer. Regression analysis also found that the temperature of the air layer between the positive correlation with the wall heat flux characteristics. And the layer between air humidity and wall heat flux is a negative correlation relationship. Humidity and heat flow density relationship found here is new, didn’t see related literature research before, this is also the innovation of the paper.For statistical analysis, the result of the thesis analyzes the mechanism of heat transfer, due to the influence of temperature on the heat flux in Fourier law principle are expounded, the experiment results of predecessors had mature argument. Therefore, the mechanism of heat transfer analysis focuses on the discussion on humidity affect the heat flux. Paper respectively from three kinds of heat conduction, convection and radiation heat transfer in the way of the air layer between the humidity affect the heat transfer is discussed, the conclusion of exterior wall thermal insulation decoration system is for aluminum alloy polyurethane thermal insulation structure, because of the air layer between the only 30 mm, and the sealing is good, the convective heat transfer can be ignored, is the problem of thermal conductivity of pure gas, heat conduction and radiation is the main way of layer heat transfer between air and humidity of the air layer between the influence of heat transfer is mainly affected the radiation heat transfer. That’s because when the air layer between the humidity changes, the air layer between also produces change, the water vapor content in due to water vapor of longwave radiation has good absorption properties, and common building materials of the radiant heat is long wave radiation, so the water blocking the air layer between the radiation heat transfer between the two walls. When the humidity is bigger, the more water vapor will, its ability to block the radiation heat transfer will be stronger. On the contrary, the blocking ability will be weaker. That is in keeping with humidity affect negatively correlated to the heat transfer characteristics of the statistical analysis of results.Air humidity and heat flow density relations has carried on the empirical equation. Of composite insulation structure model, thinks composite insulation structure wall heat transfer the heat conduction problem for one dimensional plane wall, the wall heat conduction by unsteady heat conduction is simplified to the steady state heat conduction, air layer between the heat transfer in heat conduction way equivalent radiation and convection heat transfer mode, set up with one, the mathematical model of thermal conductivity of the second class boundary conditions, finally the function equation, using experimental data.Paper finally concludes that the air layer between the humidity affect the wall heat transfer. Its significance is mainly applied in humid and rainy region composite insulation wall on the integrated heat transfer coefficient calculation, the air layer between not only simple as air heat transfer problems, but also take into account the water vapor to the effect of radiation heat transfer, thus making correction to the air layer between the heat transfer coefficient, make its heat load more precise calculation, energy consumption calculation for the building, heating and air conditioning system design provides the basis of research data.