The Physiological Evaluation In Sleeping Bags And Development Of A Smart Heating Control Unit

With the improvement of people's living standard,outdoor recreation is becoming more popular and customers all over the world are fast growing.When sleeping outdoors,especially under cool environments(air temperature below 15 0C),the protective property of sleeping bag is of extremely important.Meanwhile,with the fast development of the electronic information technology,the combination of electronic information technology and textiles on one hand enhance the relative applications of the product,on the other hand,it also provide a new approach to produce more functional or smart textiles.In this project,a smart electrically heating sleeping bag was developed by combination of sensor,electronic information technology and traditional sleeping bag.The smart heating sleeping bag was aimed to improve the wears' local,as well as whole body thermal comfort.At the beginning,this report reviewed the literature on human thermal environment and also the interaction between human body and clothing,together with the method used to evaluate the thermal comfort property of clothing.In addition,the first chapter also summarized the models used to predict the operating temperature of sleeping bags,i.e.,the Holand model,the den Hartog model,the Goldman model,the KSU model and the EN13537 model.From the documented reports,it was found that all the aforementioned models focused only the global body thermal comfort,with less regard on the extremities(foot),which leads to local discomfort when using sleeping bag under the operating temperature defined by those models.Afterward,it was found that the inter-laboratory testing errors on the sleeping bag thermal insulation caused by different ambient environment and manikins may cause profound influence on the prediction of comfort temperature according to EN13537.In order to eliminate the inter-laboratory testing errors,correction on the sleeping bag thermal insulation was underwent by an empiric equation.The empiric equation was developed by the investigation on thermal insulation of three standard sleeping bags used for the formulation of the EN 13537 standard.The physiological responses and perceptual responses when using the traditional sleeping bag and electrically local heating sleeping bag(constant heating power)were also investigated and compared.It was found that the local heating sleeping bag could dramatically improve the microenvironment at the feet region.The electrically heating sleeping bags could also improve the blood flow at the toes.However,it was also found that the constant heating power might lead to insufficient heating or over heating for individuals.A smart heating system was developed by the combination of a temperature sensor,a heating pad and a microcontroller.The smart heating system was PID controlled and thus could automatically adjust the heating power of the heating pad by comparing the real-time toe temperatures and target temperature thresholds.The real-time heating power was determined after a series of calculations on the difference between the feedback measured by the temperature sensor and the pre-set temperature thresholds,and the calculations included proportional,integral,and derivative actions.A smart electrically heating sleeping bag was then developed by introduce the smart heating control system into the traditional sleeping bag.To investigate the performance of the smart heating sleeping bag,the thermophysiological responses and subjective perceptions of wearers were collected and compared.It was found that the smart heating sleeping bag could improve human thermal comfort in the feet region.Human trials indicated that both thermophysiological responses(i.e.,foot and toe temperatures)and subjective perceptions(i.e.,thermal and comfort sensations)were greatly improved in the feet region.Besides,the smart heating sleeping bag could elliminate the possible insufficient or over heating associated with constant heating power.