| According to GB50176-2016 "Code for Thermal Design of Civil Buildings",the insulation design of the enclosure structure is based on the assumption of steady-state heat transfer and adopts the calculation method of steady-state heat transfer.However,the actual external wall is affected by the dynamic change of solar radiation and temperature and the operation mode of diversified heating rooms used in the indoor room in winter,resulting in the size and direction of the wall heat transfer often reverse.However,the steady-state heat transfer is difficult to describe this thermal process,so it can not meet the actual demand for improving the indoor thermal environment in winter in hot summer and cold winter areas.It is necessary to propose a wall insulation design method based on dynamic heat transfer.The extreme choice of outdoor calculation temperature of insulation design directly determines the insulation performance of external walls.How to scientifically and rationally select it is worthy of discussion and research.This paper can provide some reference and theoretical support for the determination of outdoor calculation parameters of thermal insulation design in hot summer and cold winter areas and the development of building thermal technology system.The conclusions are as follows:(1)Outdoor calculation parameters of thermal insulation design: The selection of typical days is based on the cumulative non-guaranteed days of the internal surface temperature of each facing wall,and the typical days under extreme climate conditions are obtained under the external wall construction conditions that are exactly not equal to 0,and the hourly meteorological parameters of the date with the highest frequency of typical days are used as the outdoor calculation temperature of winter thermal insulation design.Based on this,GH self-programming method is used to select and verify the typical day parameter set of eight typical cities in this region,and it is concluded that the selection of typical days has nothing to do with the typical wall structure,but is related to the most unfavorable conditions of outdoor dry bulb temperature and solar radiation fluctuations from time to time.Taking the typical city of Wuhan as an example,four calculation periods of 21 days,15 days,9 days and 3 days were constructed as the control group and compared with the typical day for 1 day.It was concluded that the extreme of the typical day was also affected by the extreme of the adjacent days of the typical day,and the calculation period was also an important parameter affecting the design of exterior wall insulation.The influence of the initial temperature value could be eliminated by using the calculation period of 9 days in Wuhan.Although the duration of 1typical day is affected by the initial temperature value,it can still meet the accuracy of winter wall insulation design from the perspective of engineering application.(2)Selection of typical cities: The dynamic calculation method is adopted to first define the distribution characteristics of outdoor thermal boundary conditions(outdoor dry bulb temperature,solar radiation),and use the hierarchical clustering algorithm to determine the number of winter heating hours and solar radiation.As clustering objects,the regional distribution characteristics of winter outdoor dry bulb temperature and solar radiation in hot summer and cold winter regions were explored,and eight cities of Wuhan,Hangzhou,Hanzhong,Fuyang,Yibin,Shaowu,Mengshan and Lianzhou were respectively selected as typical climate representatives.Through the selection procedure of typical days,the data sets of typical days of eight cities were obtained under dynamic calculation conditions.By comparing the difference of wall thickness between the steady-state calculation method and the dynamic calculation method in eight typical cities,it is concluded that the wall thickness of the enclosure structure calculated by the steady-state calculation is thicker than that calculated by the dynamic calculation method.Moreover,it is concluded that the more cold the outdoor climate is,the higher the accuracy of the external wall insulation design required by the steady-state calculation method is,and the warmer the outdoor climate is in winter.The less accurate the wall is calculated using the steady-state method.(3)Interior calculation parameters of exterior wall insulation design: Taking typical residential buildings in hot summer and cold winter areas as the research object,this paper studied the variation characteristics of indoor air temperature in typical city Wuhan under four intermittent heating operation modes through the implementation of Honeybee energy consumption analysis plug-in in Grasshopper parametric platform.The indoor calculation parameter set of thermal insulation design under different intermittent heating room operation mode in typical city Wuhan is obtained.(4)Outdoor calculation parameters of thermal insulation design in intermittent air conditioning heating operation mode: External wall insulation design in intermittent air conditioning heating mode can only reduce the basic indoor thermal comfort requirements in part of the time,and reduce the requirements of the cumulative unguaranteed hours of external wall internal surface temperature in time distribution.The selection method of outdoor calculation temperature for thermal insulation design in full air conditioning heating mode is taken as the model.An outdoor calculation temperature selection method for thermal insulation design based on intermittent air conditioning heating operation mode is established.Based on this method,the typical day of insulation design in the typical city of Wuhan under four intermittent air conditioning modes is calculated.January 25,2016 can be used as the typical day of Wuhan in winter under the operation mode 1 and 3 of intermittent air conditioning rooms.January 25,2008 and January 26,2008 are considered as typical days of external wall insulation design for intermittently air-conditioned room operating mode 2 and operating mode 4,respectively. |
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