Energy Saving Evaluation Of The Envelope Of Rural Residential Building In Cold Climate Based On The Cost Benefit Analysis

In China,the total amount of rural residential building is large,of which construction level lags behind the urban residential building.The existing rural residential buildings have problems such as high energy demand for heating and cooling,insufficient heat insulation of the building envelope which influence thermal comfort.With the increasing support government and living standard improvement,how to build low-cost,comfortable and energy efficient rural residential building has become a critical issue of the current rural construction.Taking advantage efficiently of climatic condition is an effective means to reduce the overall energy demand of a rural building,and also can improve the thermal insulation and heat storage effect of the building envelope,in order to improve the energy-saving effect and indoor comfort.The specific research content is mainly divided into the following aspects:Firstly,through the onsite survey of rural residential buildings,the design,construction,cost issues involving rural residence and economic status of residents were studied in the thesis,then the typical model of rural residential building in cold region was summarized.The infrared thermography,temperature and humidity tester and other instrument were used to test the indoor thermal environment and thermal performance of the building envelope in winter.The indoor thermal environment,comfort level of rural residence and the issues of energy saving in existing building were obtained,then the structural system and wall structure applicable to the rural residential building in cold climate region were sorted out.Secondly,the passive energy-saving technology strategies in the low-energy rural residential building demonstration projects and solar decathlon competition cases were summarized.The passive technical design strategies suitable for rural residential building in cold climate region were proposed,which were based on thermal insolation and sun shade in different season.Thirdly,Designbuilder was used in the thesis for performance simulation on the typical rural residential building summarized before.1)The temperature fluctuations of inner and outer surfaces of the wall structure were simulated,the differences in heat storage performance of different wall structures were analyzed.2)The influence of the design parameters and setting orientation of opaque double-wall,Trombe wall,heat storage roof,attached sunspace on the indoor thermal environment and heat transfer of the building envelope was simulated.The suitable design parameters of passive technology were obtained,the potential of passive technology for temperature control in different spaces is quantified.From the perspective of the indoor thermal environment improvement,better passive technology application strategies of envelope for living room,east bedroom and west bedroom were obtained.Finally,a technology evaluation method for passive enclosure structures of rural residential in cold region was established in the thesis,which was based on cost-benefit.The incremental cost during construction phase,incremental benefits during service phase of different wall structures and passive energy-saving technology were calculated,then the application suitability of wall structure and passive technology from the perspective of cost-benefit was studied.The research was concluded that the structure of the grass brick wall has better economy.The comparison was shown that the east and west bedrooms are economically superior with heat storage roof,with net present values of 1758.3 and 1852.4 respectively.The living room with south-facing non-light-transmitting double-walls and additional sunlight room had better economy.The net present value was 7879.4 and 7264.7 respectively.The design ideas for the application of passive envelope energy-saving technology in rural residential building in cold climate region was provided in the research,and the suitability of passive technology applications from the perspective of cost-benefit was evaluated,which has practical guiding significance for the energy-saving design of rural residential building in cold climate region.