Study On Indoor Air Environment And Optimization Design Of Fresh Air Requirement And Air Distribution In Typical Bedroom Of Nursing Home

The aging of China and the world continues to deepen,the industry of pension institutions is growing rapidly,professional nursing makes institutional pension become the choice of more and more people now and in the future.The elderly in nursing institutions spend up to 95%of their time indoors every day,and indoor air environment is particularly important for the elderly’s health.However,at present,no matter the related scientific research or related standards of nursing homes,there is a lack of exploration and guidance for the indoor air environment construction of nursing rooms.This paper studies the air environment of typical bedrooms in nursing homes and the fresh air volume and air distribution of fresh air system,and puts forward suggestions for optimizing the design method of fresh air system,so as to improve the indoor air quality of such rooms.In this study,a typical bedroom of F nursing home in Xi’an City was firstly taken as an object to conduct field tests and numerical simulation to explore indoor thermal and humid environment and air quality in summer and winter.The summer test results showed that the indoor temperature was above 28℃,the relative humidity was up to standard,the CO₂ concentration was below 1000 ppm,and the PM_2.5 concentration was over 25μg/m3.Simulation results in winter show that indoor temperature is low,relative humidity is up to standard,CO₂ concentration and PM_2.5 concentration will exceed the standard value,and indoor PM_2.5 pollution is more serious than in summer.In winter,it is more necessary to set fresh air system to improve indoor air environment.Secondly,in winter,the temperature field,velocity field,CO₂ distribution,PM_2.5distribution,air age,comfort and ventilation efficiency of the sleeping area of human body were studied under the fresh air requirement determined by different methods in the typical bedroom.The study shows that under the condition of radiant floor heating,the CO₂ concentration in the human sleeping zone exceeds the standard value under the new air requirement determined by the CO₂ concentration control method.In the range of new air volume studied,the fresh air requirement that can meet the requirements of indoor CO₂ concentration cannot meet the requirements of PM_2.5 concentration.Under the condition of floor radiant heating,indoor air quality,comfort and ventilation efficiency are good according to the fresh air requirement determined by 35 m3/（person·h）index.Under the condition of radiator heating,the indoor environment formed by the fresh air requirement determined by the new air volume index of 30 m3/（person·h）is better.Finally,the air quality,comfort and ventilation efficiency of human sleeping zone under the fresh air system with different air distribution in winter were studied.The results show that in the radiant floor heating condition,the indoor air quality and CO₂ removal effect of the up-sending and down-returning air structure are better,the comfort of up-sending and down-returning air structure is better and the removal ability of PM_2.5 is stronger,and the ventilation efficiency of the variable working area is higher.Under the condition of radiator heating,the up-sending and up-returning air distribution can better ensure the air quality in the sleeping area of human body and has strong ventilation capacity.The variable working area has better comfort in air supply and strong CO₂removal capacity.The up-sending and down-sending can most effectively eliminate PM_2.5.In addition,floor radiant heating is not conducive to vertical wall attached and variable working area air supply air distribution,affecting the effect of air supply.This study provides a reference for the design optimization of fresh air volume and air distribution in typical bedrooms of nursing homes,which is helpful to create a healthy and comfortable indoor air environment for the elderly.