Analysis On The Factors Affecting The Mean Thermal Transmittance (Km) Of The External Walls In The Energy-saving Buildings

At present, the energy problem is widely emphasized by every country in the world. It has become one of the four key problems which affect the existing and development of human society. With the fast development of Chinese economy, the energy has become in short supply. Because the new energies development is hard to alleviate the nervous situation of energy supply in short term, the research and application of energy conservation is widely emphasized by every country in the world. In China, energy conservation has also been taken as a key mission in the economy development.The building energy consumption holds a large ratio in the nation's gross energy consumption for every country;it varies between 25% and 40%. It's understandable that building energy conservation has taken priority in the energy conservation for every nation. In China, it has made much progress in the work of building energy conservation during last twenty years. But there are still lots of work to do as compared with the developed countries. As we know, the energy consumption of every unit building area is still much too high and the energy utilization rate is also much too low in China (it is about 33% in China, as that of 50% on average in Euro and USA, 57% in Japan). And also less systematic research of the building energy conservation has been undertaken in China. Therefore, it is significant to strength the research, application and promotion of the building energy conservation in China.The building energy conservation research and application is a systems engineering, which involves building materials, building construction, building design, building equipment, the standard of energy conservation, the policy of energy conservation and the education of energy conservation and so on. Specifically, the value of mean thermal transmittance (Km) of building external walls is an important index for the building energy consumption. So, , which is published in 1996, has made a specific regulation of the limit values of Km for each design region in China.According to situation of the brick mixture construction in Baotou region of China, this thesis has made deep, systematical and scientific analysis on the factors which affect the mean thermal transmittance (Km). It provides a clear understanding of the factors which affect the Km. With the method of mathematics analysis, this paper has studied the mean thermal transmittance (Km) of different room elevation unit in the project. This research will provide guides to make reasonable choice of room elevation unit in the calculation of Km. It is significant to make sure the building energy conservation design to meet the Energy conservation design standard.