| Various physiological parameters of the human body fluctuate within a certain range every day,the existence of this kind of fluctuation is not shifted by human will and actions.Although all parameters are basically maintained within the normal range,from the perspective of thermal comfort,the rhythmic changes of physiological parameters may cause thermal discomfort.Current thermal comfort research on circadian rhythm changes focuses more on the difference between day and night,that is,to study the physiological parameters and thermal comfort of the human body in the sleep state,or to compare the awake state with the sleep state.However,compared with sleep time,people spend more time staying awake a day,and the time span is more than ten hours from early morning to late at night.However,the current thermal comfort research on circadian rhythm changes during waking hours is not perfect.This article will use this as a starting point for investigation and research.Starting from the basic theories of building environment,physiology and psychology,this article uses a combination of physiological parameter testing,environmental parameter measurement and subjective questionnaire surveys to collect physiological parameters and questionnaire data of healthy young people at different times of the day,analyze and quantitatively evaluate Significance of various physiological indicators over time and their applicability as thermal comfort indicators,To help design the most suitable indoor thermal environment for the human body in different periods.The experiment was carried out in a constant temperature and humidity laboratory,14 healthy young students were recruited as subjects,and two parts of the experiment were carried out.In the first part of the experiment,three steady-state conditions were selected,the relative humidity and air flow rate were kept constant,and the air temperature was set as the variable.The subjects were asked to fill in the questionnaire and collect their physiology parameter in the room at 18,21,and 24.The second part of the experiment needs to refer to the subject’s thermal feedback.When the experiment start,the indoor temperature will be increased slowly,and the thermal comfort temperature range will be obtained based on the subject’s selfevaluation.The physiological parameters collected in the experiment include ECG(heart rate and heart rate variability),blood pressure,skin temperature,and armpit temperature.The experiment time is 9:30-10:30 in the morning,3:30-4:30 in the afternoon,and 9:30-10:30 in the evening.Experimental data processing adopts methods such as analysis of variance,T test,and linear regression analysis.The research results show that the circadian rhythm will have a significant impact on the human body’s thermal sensation.The specific manifestation is that the thermal sensation in the morning is significantly lower than that in the afternoon and afternoon.In a comfortable thermal environment,the circadian rhythm has little effect on thermal comfort,but the thermal comfort in a colder environment will vary with time.Skin temperature,armpit temperature,and heart rate variability in cold environments are significantly related to circadian rhythms.Indoor personnel prefer a warm environment in the morning,have a stronger ability to keep out the cold in the afternoon and night.This conclusion will provide optimization opinions for the design of indoor thermal environment in the future.For the HVAC industry,designing a thermal environment based on human rhythms will provide new ideas for energy conservation and thermal comfort research.This is also in line with the current development trend of intelligent and humanized air conditioning,it has strong practical significance. |
