Thermal Insulation And Energy Conservation Analysis Of The Small Concrete Hollow Block Wall In Hot Summer And Cold Winter Zone

The poor thermal performance of single small concrete hollow block wall (called block wall for short hereinafter), the climate characteristics of hot summer and cold winter zone and the building energy-efficient requests of our country are all the urgent needs to improve the thermal performance of block wall. This article based on Hangzhou climate is mainly to improve the thermal performance of block wall by compounding thermal insulating layers. The research focuses on the analysis of the best insulating form and systems suitable for Hangzhou regional identity and economic characteristics.First, the winter and summer temperature fields of pilot residential building were monitored on site. The building is enclosed with walls, which are compounded with blocks and external thermal insulating system. The experimental results show that the thermal performance of the composite wall could make the temperature of the indoor air and the internal surface of the enclosure wall more stable, could improve the indoor thermal environmental quality, could advance the indoor comfort effectively and at the same time could obtain energy-saving effect.Secondly, based on the monitoring results of the pilot building, transient thermal transfer simulation by finite-element method is proved effectively for the good agreement between measured and simulated temperature. Thus concerned problems with different insulating forms, including the temperature stability of the internal surface of the enclosure wall, the temperature difference between the internal surface and exterior surface of the block wall and the heat bridge effects, are compared and analyzed by finite-element method. The simulation results show that the external insulation form is better than internal insulation form in these three aspects.Thirdly, the advantages and disadvantages of different insulation forms and engineering applications are discussed in order to find the best insulation form in hot summer and cold winter zone. The external insulation form is the best way. This article generalizes the application experience and results of external insulation form in hot summer and cold winter zone. And it presents some relevant recommendations of external insulation systems suitable for this zone.Finally, this article chooses degree-day method to calculate the energy consumption during heating time and the cooling load coefficient method to calculate the energy consumption during cooling time. The combination use of these two methods is a simple and convenient way to calculate the energy consumption through walls in hot summer and cold winter zone. The optimal thickness of insulating material is determined based on the life cycle cost (LCC) methodology. And the economic recovery period of insulating system is calculated using dynamic investment method. This article also gives a simplified method to calculate the energyconsumption through unit surface of external wall during heating and cooling time in Hangzhou. The simplified method is convenient for engineers to evaluate the energy-saving economical efficiency. That investment for energy-saving walls could be recovered quickly, and external insulated walls save both energy and money.The work in this article improves the thermal performance of the block wall and reduces temperature stress caused by temperature changes. It makes better promotion and application for block wall in hot summer and cold winter zone. The work also improves the indoor thermal environmental quality and enhances the indoor comfort. At the same time it could further improve residential energy efficiency measures, reduce atmospheric pollution and the greenhouse effect in order to accelerate the development of block constructions moving to national energy-efficient construction standards in hot summer and cold winter zone.This research is part of Hangzhou Technology and Development Project------thekey technical study and application of the green and energy-saving residential system(No. 200432360),which is sponsored by Hangzhou Science and Technology Bureau and Hangzhou Construction Committee.