Study On Foot Heating Toimprove Thermal Comfort Ofindoor Workers In Winter

Modern people spend more than 90% of their time in indoor environments,so the impact of indoor thermal environment on human thermal comfort cannot be ignored.Human thermal comfort can be improved by adjusting indoor thermal environmental parameters.The personal comfort system can adjust the local thermal environment by local air supply,local heating and local cooling.It is more efficient and energy-saving than the traditional air conditioning system that controls the thermal environment as a whole.At present,most of the research on thermal comfort is aimed at the environment of office,classroom,residence,etc.,but the research on the workshops for workers to carry out physical activity is very small.Research on the thermal comfort of working people in such a thermal environment can improve the work efficiency of people while improving the working environment of personnel.The workshops are generally high and large spaces,the use of central heating in winter consumes a lot of energy and the effect is not good.It is more economical and effective to use local control of the thermal environment.This paper focuses on the improvement of the thermal comfort of physical activity workers by local heating in winter conditions.Simulated the common temperatures and physical activities in the non-concentrated heating workshop in winter through experiments,and studied the effects of the heating foot pad on the human thermal sensation,thermal comfort and work efficiency.Then,this paper also observed the influence of the heating foot pad on the temperature field and velocity field around the workers through numerical simulation.Finally,combined with the results of experiments and numerical simulations,this paper explored its practical applicability under different low temperature conditions.The main conclusions are as follows:Foot heating significantly improved the local thermal sensation and overall thermal sensation of the human body in a cold environment.The feet thermalsensation had a strong correlation with the overall thermal sensation when the feet were heated,and when the feet thermal sensation vote value reached 1.2,the overall thermal sensation reached the thermal neutral state.Foot heating not only significantly improved the thermal sensation of human body in cold environment,but also significantly increased the human thermal comfort.The research on the relationship between the overall thermal sensation and thermal comfort under foot heating showed that the overall thermal comfort was best when the overall thermal sensation of human body was warm.The thermal expectation and thermal acceptability of personnel on the thermal environment was consistent with the thermal comfort questionnaire: in the cold environment with foot heating,the thermal acceptability of personnel to the environment was not the best,and people preferred that their overall thermal sensation was warm.Compared with no heating,the work efficiency of personnel when the foot was heated was significantly improved,and the work efficiency was related to the overall thermal sensation and thermal comfort of human body.When the subjective feeling of human body was better,the work efficiency was higher.Foot heating had a certain effect on human physiological parameters.As the ambient temperature increased,both the human skin temperature and the cochlear temperature increased.Skin temperature,cochlear temperature and overall thermal sensation were significantly correlated: as the overall thermal sensation increased,both skin temperature and cochlear temperature increased.The numerical simulation of the indoor thermal environment showed that the temperature around people was significantly increased in a certain range when local heating pad was used,the temperature distribution in the vertical direction was more even,and the speed met the comfortable requirements of thermal environment.Further simulation showed that in the low temperature environment of 11 ?,the heating area and heating temperature are 0.7m×0.7m and 57? or 0.6m×0.6m and65? respectively could maintain good thermal comfort for personnel.Through this study,it was found that the local heating method of the heating footpad can ensure the thermal comfort of the worker in the low temperature indoor environment,significantly improve the work efficiency of the personnel,and its energy consumption is very low.Based on the research results,it is recommended to adopt this local heating method to improve the thermal comfort of workers in the low-temperature workshop in winter.