The Study On Energy Conservation Of Timber Frame Residences In Chongqing

As reform and opening-up has driven deeply in the past 30 years in China, the fast development of national economy brings along the high growth of energy industries. Construction is one of the areas in energy demand growing fast. How to reduce the construction energy consume is a big problem urgently to be solved. Timber constructions has been wildly applied in North America and the other developed areas for a long time because of its attractive appearance, energy saving, comfort, earthquake-resistance and close to nature. By taking the climate of Chongqing into consideration, the research of timber building in indoor thermal and moist environment, loading characteristic and energy efficient will be studied in this paper.First, based on the analysis of previous research work on thermal comfort model for naturally conditioned spaces, a humidity and velocity correction model is presented considering climate characteristics in Chongqing. And the correction models are verified by a serial of subjective questionnaire surveys and objective thermal comfort data.in dormitories in Chongqing University and residential buildings. The results show that the correction model is more accurate. But the correction model and the original one have a big difference between the result of evaluations and surveys. So with linearity regression analysis, the relationship of mean thermal sensation (MTS) and effective temperature (ET) is established based on the data of surveys by linearity regression analysis: MTS=0.53 ET-13.53(R2=0.928), and the 80% acceptable thermal and humid comfort ranges is 22.6-26.6℃in temperature, the range is also compared with others.Secondly, serval typical building envelopes of wood-frame residence are collected by surveying and consulting related data in summer. After combining the common forms of wood-frame building envelopes, 16 kinds of experimental scheme are determined by adopting the orthogonal experimental design method. A numerical simulation for indoor thermal environment of the 16 kinds of experimental scheme is carried out using energy simulation program EnergyPlus.Then, an evaluation of thermal environment of 16 kinds of experimental scheme is made with the improved model, and validating the evaluation results using thermal comfort evaluation model which is proposed in the paper.Thirdly, according to the determined optimal experimental scheme, a practical model is builded. In this research energy efficiency was evaluated based on field testing for wood-frame residence in Chongqing, including heat transfer coefficient of timber wall, the temperature and humidity indoor and outdoor, and the internal and external surface temperatures of building envelop. The heat transfer coefficient of timber wall is 0.50 W/(m2·K), attenuation multiple is 9.9 and delay time is 5h. The differences between the measured values and the calculation values are analyzed. An analysis of the internal surface temperature of building envelope shows that the thermal insulation of wood-frame building envelope isn't satisfied with the requirement of Thermal design code of civil building, and improving the thermal insulation performance should give priority to the roof. The paper proposes two measures for improving the thermal insulation performance of the roof and the analyses the feasibility of two measures in theory. Besides, the indoor temperature and humidity distribution of wood-frame residence is also studied. Comparing with the 50% energy-efficient brick-concrete residence, the results show that humidity regulation performance and comfortableness of timber construction is superior to 50% energy-efficient brick-concrete residence, but the thermal stability of wood-frame residence is poorer than 50% energy-efficient brick-concrete residence.Finally, the energy consumption of a wood-frame residence during extreme weather days and typical meteorological year in Chongqing is calculated by building energy simulation program, EnergyPlus, including air-conditioning load and the annual power consumption. And the energy consumption of wood-frame residence is compared with 65% energy-efficient brick-concrete residence.