Study On Thermal Insulation Thickness And Carbon Emission Calculation Of Temporary Buildings Used In Winter Olympics

Buildings are one of the three major areas of energy consumption and play an important role in the process of carbon emission reduction.According to the concept of sustainable development,in order to implement the requirements of green Olympic Games,a large number of temporary buildings that can be dismantled,easily recycled and conducive to the recovery of the environment in the Yanqing Competition Zone of Beijing 2022 Winter Olympic Games were adopted.Yanqing Competition Zone is located in the south of Xiaohaituo Mountain,which has a wide range of altitude variations and a distinct vertical distribution of climate.Thermal insulation of temporary building envelope is essential for creating a good indoor environment,reducing heating energy consumption and maintaining environmental friendliness.In this paper,the thickness of insulation materials of temporary buildings in Yanqing Competition Zone was analyzed from the perspective of economy and carbon emission.The service life of temporary buildings is generally lower than that of permanent buildings,and the movability makes the operation process of its whole life cycle different from that of permanent buildings.Based on the above characteristics,the carbon emission of temporary building used in Yanqing Competition Zone in each stage of their whole life cycle was calculated.In this thesis,a model of a container house in the Yanqing Competition Zone was established,and the natural room temperature was simulated by Energy Plus.The simulation was verified with some measuring values.Based on the meteorological parameters at two altitudes in the Yanqing Competition Zone,the heating energy consumption of the container house with different insulation thickness was simulated.Considering the production stage of insulation materials and the operation stage of temporary buildings,the“economic thickness”and“thickness of minimum carbon emission(δ_car)”of different insulation materials under different service life of temporary buildings were determined by taking the lowest economic cost or the lowest carbon emission as the objective function,respectively.Then,the appropriate thickness of different insulation materials is discussed by varying the economic and carbon weighting coefficients and adding the carbon cost.During the Winter Olympic Games,field tests were carried out on the indoor and outdoor environment and heating energy consumption of the Wax Cabins in the competition zone.A model of Wax Cabins was built to carry out relevant simulation studies and the simulation was verified with test data.The“economic thickness”and“thickness of minimum carbon emission”of rock wool under different service life of the Wax Cabins were calculated,and the economy and environmental protection of Wax Cabins with thickness of 100 mm of rock wool under different service life were analyzed.At the end,taking a Wax Cabin as an example,the whole life cycle carbon emissions were calculated according to the actual operation process.The main conclusions of this article are as following:1)Due to the mountainous conditions,the average temperature of the coldest month varies greatly from the altitude of 950 m（close to the Yanqing Olympic/Paralympic Village）to 2177.5m（close to the Top Starting Area）.The average temperature of the coldest month（January）at the altitude of 950 m is-8.1℃and the average temperature of the coldest month（December）at the altitude of 2177.5 m is-17.6℃.Compared with the meteorological data of Beijing,the average monthly temperature at the altitude of 950 m and 2177.5 m are 0.9 to 6.6℃and 7.3 to17.1℃lower,respectively.The insulation performance of the Wax cabins was improved by adding 1 cm aerogel felt to the external wall,and the natural room temperature of the room was increased by 0.2～1.81℃at night.2)The heating energy consumption of the container house decreases with increasing thickness of insulation material and the rate of decrease becomes slower and slower.For example,at the altitude of 2177.5 m,the rate of change of heating energy consumption decreases from 31%to 5%,32%to 4%,and 33%to 4%when rock wool,extruded polystyrene（XPS）,and polyurethane（PU）increase from 20 mm to 200 mm,respectively;and the rate of change of heating energy consumption decreases from 30%to 5%when the high performance vacuum insulation panel（HVIP）increases from 2 mm to 20 mm.3)The analysis results of the insulation thickness of the container house show that the economic thickness andδ_carare affected significantly by the service life of the container house.With the increase of service life,the economic thickness tends to increase rapidly and then grow slowly,and theδ_cartends to increase approximately linearly.For the same insulation material,theδ_caris larger than the economic thickness.The applicable insulation materials are different under different service life when considering the net volume of the container house.For example,at the altitude of 2177.5 m,when 80%of the net volume is satisfied,from the economic point of view:when the service life of the container house is 1 to7 years,the cost of using XPS as the insulation material is the lowest;when the service life is 8to 12 years,PU can be used as the insulation material;when the service life is 13 to 20 years,HVIP is needed.From the perspective of carbon emissions,when the service life is 1 to 4 years,the carbon emission of PU as the insulation material is the smallest,and HVIP is required as the insulation material when the service life is 5 to 20 years.The results of considering different weighting coefficients of economy and carbon emissions show that the larger the economic weighting,the smaller the insulation thickness.From the perspective of additional carbon cost,the economic thickness of the additional carbon tax that calculated by the carbon tax of 60RMB/t that referenced from the existing literature is similar to the economic thickness.When the carbon tax is 960 RMB/t（electricity price increase of 0.55 RMB/（k W·h））,the economic thickness of the additional carbon tax increases significantly compared to the economic thickness:when the service life is 20 years,rock wool,XPS and PU increase by about 20-25mm,and HVIP increases by about 3 mm at the altitude of 2177.5 m.4)Considering the net volume of the room,the analysis results of economic and carbon emission benefits of Wax Cabins with thickness of 100 mm of rock wool under different service life show that:from an economic point of view,the service life of the Wax Cabins is 7.5 to 11years when the economic benefits are better;from the perspective of carbon emissions,carbon emissions are smaller when the service life is 3.5 to 7 years;the weight coefficient method is used to calculate that when the service life is 4 to 7 years,the thickness of the insulation material under different weighting coefficients of economy and carbon emissions is similar to that of rock wool 100 mm.After adding a carbon tax of 960 RMB/t,the economic benefit is better when the service life of the Wax Cabins is 6 to 8 years.5)During the whole life cycle of the Wax cabins（20 years of life）,the material production stage and the building operation stage are the main stages of carbon emission,accounting for19.53%and 70.59%,respectively.Among them,metal materials and insulation materials are important parts of the material production stage,accounting for 47.85%and 39.23%respectively;carbon emissions from heating are the main part of carbon emissions in the operation stage of temporary buildings,accounting for 77.83%.The total life cycle carbon emissions of the Wax Cabins with 100 mm rock wool for the external walls and 100 mm glass wool for the roof and floor are 33.89 t CO₂ e.The total life cycle carbon emissions of the Wax Cabins withδ_carof rock wool（323 mm）are 27.55 t CO₂ e.The adoption ofδ_carcan reduce carbon emissions by 18.7%.