Research On Active Dynamic Composited Envelope Of Low-energy Building

Energy resource and environment are the great social problems that every country especially our country is faced with. With the advancement of the society and development of technology, the advanced architectural technology offered us a comfortable living environment, consumed 30% of the total energy while created environmental pollution to the same proportion. Building energy conservation is the important approach to solve the energy resource problem.It is very necessary to increase the use ratio of energy resource conspicuously which established in our country in order to remiss the contradiction between energy resource and social and economic development. The objective of this subject is based on the purpose and requirement of building energy saving, take the OOOPK building of Huazhong University of science and technology in Wuhan as a case, An innovation envelope——Active Dynamic Composited Envelope (ADCE) has been put forward. while recycling the indoor exhaust air of heat-exchanging been actively put into the air layer of ADCE, building energy can be sufficiently recovered, the thermal characteristics of envelop can be improved, the thermal radiation of internal envelop surface can be regulated, which achieved twofold purposes of energy saving and improving thermal comfortable. Aiming at ADCE, this paper applies the method of theoretical analysis, combined with simulation and measurement to research. The main research contents are as follows:(1) Based on the correlation theory of building thermal physics, it analysed the heat transfer model and heat transfer coefficient of ADCE, meanwhile, provided some transfer computation of ADCE according to correlation theory and came to a conclusion.(2) According to the comparison of simulation and testing when ADCE was in different seasons and different condition, it discovered that active ventilation of ADCE not only improved the envelope's heat-shielding performance in summer and thermal insulation property in winter, also showed better adjustment function to the temperature of internal surface of envelope. At the same time, the comparison of simulation and test show that the results are consistent. (3) Using the simulation to analyse the ADCE in different seasons and different condition, it indicated that active ventilation in different seasons adjusted the thermal radiation of internal surface of envelope, enhanced "cold radiation" of internal surface in summer and reduced "cold radiation" in winter. Meanwhile, according to the theoretical analysis, simulation and test, it draw a conclusion that the ACDE has a dynamic heat transfer coefficient. And rational proposals to initiative adjust the ACDE dynamically were given according to different climates.(4) Taking the 000PK building as a case, according to the simulation analysis of ADCE and building environment in different seasons and different conditions, it indicated that, in high temperature circumstance of summer days, active ventilation not only enhanced insulating performance of envelop, reduced the thermal radiation of internal surface, also reduced indoor temperature, improved the thermal comfort. Similarly, in low temperature circumstance of winter days, active ventilation not only enhanced thermal insulation property of envelop, changed the thermal radiation of internal surface, also inhibited the indoor temperature reducing, adjusted the thermal comfort. As far as architectural system is concerned, active adjustment of ADCE caused "cold wall" effect in summer and "warm wall" effect in winter, which will be helpful to energy saving and comfort adjustment.Taking the 000PK building of Huazhong University of Science and technology as a case, this paper researched on the ADCE by means of theoretical analysis, simulation and testability verification. The methods and conclusions may be useful to building energy efficiency theories, research and design.