Study On Energy-saving Optimization Of Exterior Wall Of Coastal High-rise Residential Building In Cold Area Based On Winter Wind Environment

Due to the influence of Marine monsoon and sea and land wind,the wind speed in coastal areas is always larger than that in inland areas.However,neither the design code nor the energy saving code has a special effect on the distribution of wind speed ladder in the strong wind region in winter.According to specification for design of heating ventilating and air conditioning in that both palisade structure heat consumption and door window air cooling osmotic quantity is closely related to building surface wind speed,and building surface wind speed is not only influenced by the local environmental climate,due to the existence of the construction of wind,shunt,wind down the wind will have an effect of architectural surface wind speed,Thus,the heat transfer coefficient of the building surface is affected,and then the heating load demand of the building in winter and the overall energy consumption of the building are affected.Due to the unified design code of high-rise buildings,there is no special design requirements for winter wind in the same building with different height areas,and the thermal insulation performance of building envelope（especially the windward side of building exterior wall）is strengthened.At the same time,due to the related constraints of building construction technology conditions and project cost,the influence of high wind speed and gradient wind on the heating load of high-rise residential buildings in coastal area has not attracted enough attention,thus causing a certain increase in building energy consumption and energy waste.In this study,CFD and Design Builder simulation tools were used to analyze the convective heat transfer on the building surface and the heat load of winter heating of typical high-rise residential buildings in cold regions under the influence of vertical gradient wind.A mathematical model of quantitative relationship between longitudinal gradient wind speed and convective heat transfer coefficient of building surface and heating load in winter of high-rise residential buildings is established.Based on the numerical calculation of the mathematical model,this paper puts forward the energy-saving optimization strategy scheme of the exterior wall of high-rise residential buildings in cold area,and systematically analyzes the energy-saving effectiveness of the single building and building residential areas after the implementation of the scheme from different levels.The specific research conclusions are as follows:Through a font and cross the horizontal and vertical wind speed distribution of high-rise residential into numerical simulation and curve fitting analysis results indicate: building longitudinal wind environment gradient relatively obvious,the basic residential building according to the wind speed characteristics of the longitudinal can be divided into three regions: building area,middle area and lower in the upper wind speed change rule has the obvious difference;The horizontal wind environment is axisymmetric,and the wind speed is the least near the axis.Through the simulation analysis and curve fitting analysis of the convective heat transfer law caused by wind speed in two typical high-rise residential buildings,it can be seen that: One word and cross high-rise building in the longitudinal direction of the convective heat transfer coefficient change law in piecewise linear relations,through the slope of the curve fitting results are different,can be vertical convection heat transfer coefficient in accordance with the construction of high-rise building is divided into three parts,respectively for the lower zone,middle area and the upper floors.Due to the axisymmetric characteristics of convective heat transfer coefficient in the transverse direction,it is not suitable to divide the transverse area of the building.High-rise residential lower the convective heat transfer coefficient is relatively small,and the top of convective heat transfer coefficient is relatively large,so can consider without any increase in initial investment under the premise of building external wall thermal insulation structure,the lower the building exterior wall thermal insulation layer thickness is reduced,to reduce the thickness of the move to the outer wall part of top area,in order to reduce the convective heat transfer coefficient of top area,Realize the reduction of building thermal load and energy consumption.The quantitative relationship among the longitudinal gradient wind speed,the convective heat transfer coefficient of the building surface and the building heat load in winter was calculated,and the energy-saving optimization method of the exterior wall of high-rise residential building based on the quantitative relationship of the three was proposed.The exponential growth law of gradient wind in the longitudinal height of buildings can directly affect the convective heat transfer coefficient at different longitudinal heights of high-rise residential buildings,thus affecting the overall thermal load of buildings.The energy-saving optimization model of external wall insulation layer based on vertical partition of high-rise residential buildings was proposed,the optimal transfer thickness of external wall insulation layer of single buildings was obtained,and the energy-saving rate value of the optimization scheme of external wall insulation layer was obtained.Proposed energy-saving optimization scheme for exterior wall of high-rise residential buildings.The scheme is divided into two levels: the first level is that the whole residential area adopts fixed exterior wall energy saving optimization scheme;the second level is that different buildings in different areas of the residential area adopt different exterior wall energy saving optimization scheme respectively.The monthly average energy saving rate is 1.56% when the fixed external wall energy saving optimization scheme is adopted uniformly in the one-line high-rise residential area（the external wall insulation layer of all the low-rise areas is transferred to the high-rise areas according to the thickness of 10mm）,and the monthly average energy saving rate is 2.43% according to the optimization scheme of the external wall of buildings in different areas.The exterior wall optimization scheme in different areas can save up to 0.87% energy compared with the unified fixed optimization scheme.According to the unified exterior wall insulation optimization scheme,the average monthly energy saving rate of the cross high-rise residential area is 0.98%,and the average monthly energy saving rate of the exterior wall optimization scheme in different regions is 1.76%.Compared with the unified fixed optimization scheme,the exterior wall optimization scheme in different regions can achieve a deep energy saving of 0.78%.