Study On The Effect Of Standing And Treadmill Workstations On Human Thermal Comfort

Sedentary(sitting)behaviors are ubiquitous in modern official task.A large number of epidemiological studies have demonstrated that prolonged seated behaviors increase the risk of chronic diseases and threatens human health.Given the standing and treadmill workstations are widely accepted because of their advantages such as significantly reducing sitting time,improving work efficiency and increasing human activity.With the popularity of standing and walking office modes,new problems have arose for the environmental control of office buildings,that is,whether the existing thermal comfort evaluation models can accurately predict the human thermal comfort at different metabolic activities.The traditional PMV-PPD model is mainly aimed at the prediction of lower activity level(sedentary),therefore the current international and national thermal comfort standards based on PMV-PPD model cannot evaluate human thermal comfort accurately after the increase of metabolic rate,and the predicted value is quite different from the actual situation.Currently,there are no standards and models for predicting or evaluating the thermal comfort of the human body at higher metabolic rate levels,nor is there a way to guide the design of an office environment with standing and treadmill workstations,or with higher metabolic rate activities.There is little research on the thermal comfort of the human body.Under these circumstances,the study on the metabolic rate level of human body working in the way of standing and walking as well as the study on the influence of different metabolic rate levels on human thermal comfort can guide how to improve the parameter design of indoor thermal environment of office buildings and increase the comfort level of office environment and promote the development of healthy new office mode.In this study,the changes in human thermal sensation after the use of standing and walking workstations and the effects of different office styles on human thermal comfort were studied by means of laboratory research and questionnaire survey,statistic analysis and physiological theoretical analysis.The following conclusions can be drawn:Firstly,treadmill workstation can significantly improve the body’s metabolic rate,while metabolic rate of standing and sedentary work has no significant difference.The metabolic rates of sedentary,standing,walking at 1 km/h and walking at 2 km/h were 1.0(SD=0.22),1.0(SD=0.20),1.7(SD=0.31),and 2.1(SD=0.30)met,and were different from the reference values given in ISO-7730,ISO-8996,ASHRAE 55 and GB/T 50785-2012 respectively.Secondly,adopting standing and treadmill workstations,the body’s neutral temperature falls.In the measurement of working posture,standing,walking at 1 km/h and walking 2 km/h,the neutral temperature were 24.3,23.3,22.2,and 21.1℃,compare to the current of the PMV-PPD model predicts,the office working neutral temperature were 25.3,20.5,and 18.5℃.There is a significant difference between this two situation.It can be seen that PMV model is not suitable for high metabolic rate.In autonomous control temperature experiments,people regulating the indoor temperature according to their own habits.In the sedentary,standing,walking at 1.2 km/h and 2.4 km/h,the people to control the temperature of the 25.85,25.0,24.1,and 23.2℃,respectively.Thermal sensation stabilize in 0.5,namely between neutral and slightly warm.It shows that the 26℃temperature value is not enough to satisfy the coexistence of various office activities,which suggests that provide personal thermal comfort devices can improve personal thermal comfort.