| High temperature environment generally refers to the working environment above 35? and 32? above the production environment,which usually makes people feeling tired,physical decline and slowing down of reaction speed.It will affect human health to be serious to cause death.Therefore,it is important to take effective measures to protect the persons working in the high temperature environment for their health and enhancement of working efficiency.One of the protection measures for high temperature workers is to wear a portable cooling system.Thermoelectric cooling,also known as semiconductor refrigeration,or peltier effect,is a new type of refrigeration technology on the basis of the peltier effect.Under the current background of developing green technology and sustainable development,the thermoelectric refrigeration system has broad application and market prospects due to its simple structure,no moving parts,safety,reliability,and no pollution.So the thermoelctric cooling technology is particularly suitable for body cooling system.With the development of materials and related research,the research of thermoelectric refrigeration system has become more and more deeply.Based on the principle of thermoelectric,this paper designs a new type of human body cooling system including cooling helmet and liquid-cooled clothing,and uses the self-made thermal manikin to carry out experimental research.The cooling helmet adopts air-cooling and water-cooling methods,which can simultaneously cool the person's head and neck.Firstly,the experiment is conducted to investigate the cooling characteristics of the human body cooling system,and the effect of wind speed,liquid flow rate and refrigerator power on the helmet cooling performance is studied in detail,then the experiment obtains the optimum cooling conditions for the cooling system;Secondly,the tester wears the cooling system and evaluates the comfort of system by adjusting the experimental conditions.The studies in this paper present the following conclusions:1.The refrigerating output and system COP of the body cooling system are related to the TEC power,circulating water flow and the wind speed of fans.The TEC exists an optimum power,and the cooling helmet and liquid-cooled clothing have a good cooling characteristic in the optimum power area.The best power area of the cooling helmet is 19.2-37.4W,and the maximum cooling energy efficiency can reach 0.55;the best power area of liquid-cooled clothing is 16.8-46W,and the maximum cooling energy efficiency of system can reach 0.5.The increase of cooling helmet flow rate and system wind speed can enhance the heat dissipation as well as improve the energy efficiency of the system;the liquid-cooled clothing has a best power 66.7ml/min which makes the cooling energy reach maximum.2.With the increase of the environmental temperature,the system's refrigerating output and COP reduce.When the environmental temperature is less than 40?,the cooling system internal temperature is between 24?30?,which can ensure the wearing comfort of the human body.3.Compared with the air-cooled module,liquid-cooled module of the cooling helmet has a better heat transfer effect,and can provide more cooling capacity for the human body.The air-cooled module can enhance the helmet internal air flow,and play a role in helping to increase the wearing comfort of the human body.4.The performance test of body cooling system is conducted by healthy males.The results show that the cooling system can ensure the comfort of human body under the high temperature of 30?40?. |
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