Study On Air-flow Organization Of Atrium In City Complex During The Heating In Dalian

With the development of modern architectural design concept,the new large space architecture is peculiar and huge,and it is difficult to meet the needs of the traditional experience.Therefore,the large space buildings,especially the atrium,have put forward higher requirements for health,comfort,efficient use of energy and environmental protection.In this paper,the atrium of a complex in Dalian is further designed and discussed.Through theoretical analysis,field measurement,software modeling and other methods,the air conditioning air distribution in the atrium is studied and empirically.The CFD simulation technology is used to simulate the air distribution in winter,and the simulation results are comprehensively evaluated and analyzed,which will provide some reference for future engineering design.Firstly,the complex is briefly described,including the general situation of the project,the main outdoor meteorological parameters and the parameters of the interior design.The design of the atrium air conditioning system is briefly described.The air conditioning load and air volume of the atrium,the cold and heat source of the air conditioning,the air conditioning unit and the automatic control of the air conditioning system are introduced respectively.The design of atrium airflow organization is briefly introduced.The results show that the design conditions meet the specifications for the design requirements of the atrium in winter.However,there are differences between the actual working conditions and the design conditions.It is also necessary to demonstrate the air distribution of the actual working conditions.Moreover,the field measurement and questionnaire are carried out on the comprehensive atrium,and then the evaluation of the effectiveness of the atrium air flow is made.The results show that the measured parameters of the A and B areas of the atrium meet the requirements of the standard.However,the survey in the A District of the atrium showed that 55% of the people believed that one layer was overcooled,and 62% believed that the five layer was overheated.It shows the uneven heat distribution and the heat in the lower cooling.The survey in the B District of the atrium showed that the proportion of people who believed in overheating increased from 8% in the first layer to 24% in the five layer.Also presents the heat distribution is uneven.The uniformity of atrium air distribution shows that the temperature uniformity of the two districts is good,the maximum value of the non-uniformity coefficient is 0.047 in the A area,and the maximum value of the non-uniformity coefficient is 0.041 in the B area.The velocity uniformity of the two zone is poor,and the maximum value of the non uniform coefficient in the A region is 0.81,and the maximum of the non uniform coefficient of the B region is 0.93.The comfort evaluation of atrium airflow organization shows that the two areas predict that the proportion of the comfort population is mostly concentrated in the middle and lower parts,of which ADPI is up to 100% in the middle and lower parts while only 0% in the upper part.The evaluation of the distribution of heat in the atrium airflow showed that the number of people with PMV<-0.5 in the A area was the most,accounting for 73%,and the number of people with four layers of PMV>0.5 was the most,accounting for 63%.One layer of-0.5<PMV<0.5 in B area is the most people,accounting for 42%,and the four layer of PMV>0.5 is the most,accounting for 71%.The "chimney effect" has been found in all two areas because of the irrational distribution of the heat distribution.The airflow organization needs to be further optimized.Lastly,the CFD simulation of the complex atrium is carried out,and a comprehensive evaluation method of the atrium air flow is put forward.The influence factors of air supply angle,air speed,the vertical direction and horizontal direction of typical section deep into the work area of thermal comfort is analyzed,found that the winter air atrium angle between 15 °to 30°,air velocity is between 2.5m/s and 3m/s,air jet lap good work the thermal comfort.Through the two comprehensive factors that ensure thermal comfort and energy utilization coefficient,we use the weight coefficient method to make further quantitative analysis of the above conditions to serve as the final evaluation basis for atrium air distribution.It is finally determined that the air supply angle is 15 °,and the air velocity of 2.5m/s is the best form of air supply for the complex atrium.The author engaged in HVAC design for many years.In order to ensure the progress of the project,it is required that the distribution of thermal environment parameters in atrium should be reasonably predicted before design work.Therefore,it is very important to find a way of air supply suitable for the winter air conditioning in the atrium of the building.This paper focuses on the study of the air distribution in the atrium in winter.It is necessary to supplement the summer condition and the air conditioning organization of more types of building atrium,The initial investment and cost of the project are not concerned.And in order to simplify the model,there are certain differences between the simulated and actual working conditions.It is also necessary to carry out a more in-depth study of the above content.