| In order to cope with global climate change,China has put forward the "double carbon" goal,that is,to strive to achieve "carbon peak" by 2030 and "carbon neutral"by 2060.However,as a developing country,China is still in the stage of accelerating new industrialization,informatization,urbanization and agricultural modernization,and the foundation for comprehensive green transformation is still weak,and the pressure on ecological environmental protection has not been fundamentally relieved.In terms of the life cycle,the greenhouse gas emissions of buildings can reach about 50%of society’s carbon emissions.Therefore,innovation from the field of building energy efficiency technology is essential to achieve the "double carbon"goal.At the same time,during the Covid-19 normalization phase,droplets or aerosol particles from transmitters are identified as potential sources of infection,indoor air quality is a growing problem,and people spend 80-90%of their time indoors,so based on the poor built environment,it is necessary to adopt strategies for indoor spaces to reduce transmission risks and improve the indoor environment.This study mainly explores the pollutant dispersion and engineering control methods under the influence of different indoor flow fields and different respiratory states through experiments,numerical simulations and subjective questionnaire surveys,which are divided into three stages.(1)Exploration of energy-efficient interior design temperature using indoor thermal comfort questionnaire results.This phase firstly analyzed an important factor of thermal discomfort,i.e.local thermal sensory discomfort,using the subjective questionnaire survey method,followed by thermal acceptability poll:TSV,TCV,TAV and PPD to explore the lower limit temperature of thermal acceptability,and finally combined with the lower limit temperature of thermal acceptability as the interior design temperature to calculate the energy saving potential.The results show that:100%of students have local thermal discomfort and the current indoor temperature cannot meet the thermal comfort needs of office personnel;80%of students have acceptable minimum and maxmum lower limit temperatures determined by TAV of 20.7℃ and TSV of 22.5℃,respectively;if the interior design temperature is reduced from 23.8℃ to 20.7℃ as determined by the heating room formula,the annual savings of heat load by 2.96%.(2)The diffusion and elimination effects of human exhaled CO2 under different ventilation methods are studied on the basis of the current interior design temperature,and the design of optimized building ventilation methods is proposed.In this stage,we firstly construct the building model,indoor flow field,CO2 concentration field and temperature field by using numerical simulation method,and secondly verify the realism of the simulation by fitting the simulation results with the experimental results,and investigate the airflow organization under different ventilation methods,and finally explore the optimal ventilation method according to the simulation results.The results show that:by the effect of indoor thermal buoyancy,the location of the air outlet has an impact on the removal effect of indoor C02 pollutants,so when using air conditioning ventilation for heating,the ventilation method with the return air outlet above the room is chosen to be more conducive to the removal of indoor CO2 pollutants;the active area and breathing plane C02 of four different indoor ventilation methods are compared,and the low concentration of CO2 in the breathing plane should also be considered when considering the The uniformity of indoor flow field;analyze the characteristics of velocity flow field,pollutant concentration and temperature spatial distribution of different working conditions,ventilation effect displacement ventilation>layer ventilation>upward and backward>upward and backward.(3)For the optimized ventilation system,i.e.,replacement ventilation system,the effect of barrier height on the transmission of aerosol particles generated by human sneezing is studied and the transmission risk is evaluated.This phase firstly constructs airflow organization models for different regional sources based on the previous two parts of the study as boundary conditions and using numerical simulations,secondly explores the effects of barrier height and source location on airflow distribution and source dispersion,and finally evaluates the risk of infection from barrier height on source location.The results show that for airflow obstruction(AO),it is recommended to build a physical barrier of at least 50 cm on the desk to prevent the diffusion of airflow generated by the infected person’s cough;for the contaminant source close to the exhaust(located at C),a physical barrier height of 50 cm can perform its excellent barrier performance;for the contaminant source far from the outlet(located at A.and B),a physical barrier height of A physical barrier height of 60cm will give excellent barrier performance;if the location of the infected person is unknown,it is recommended to establish a physical barrier height of at least 60cm,which can reduce the risk of infection by 68%.This paper is of reference value and guidance for improving indoor comfort,improving indoor air quality,creating a healthy indoor environment and reducing energy consumption in buildings. |
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