Experimental Study Of Human Cooling Suit Based On Thermoelectric Refrigeration

High temperature environment widely exists in natural environment,industrial working environment and other environment.With the development of productivity and technology,more and more people are engaged in high temperature environment.The high temperature environment will cause the thermal stress of human body,which will have a bad effect on the physiological ability of human body and weaken the effectiveness and efficiency of action.If the human body is exposed to the high temperature environment for a long time,human body can't maintain the normal heat balance and the human body will be damaged by pathological heat.Therefore,it is a hot issue how to reduce the human body temperature of the workers working in the high temperature environment.The research and design of human body cooling suit has a very important practical significance.Compared with other refrigeration technologies,thermoelectric refrigeration has the advantages of no moving parts,rapid refrigeration and convenience,especially suitable for human body cooling system.In this paper,the liquid cooling suit and the hot end natural convection cooling suit are designed and studied under the conditions of high heat flux and low heat flux respectively.The conclusions are as follows:First of all,there are many factors that affect the operation of thermoelectric refrigeration,such as size factor(G),working current,temperature of hot and cold end,and so on.In this paper,the basic working characteristics of G,working current and cold end temperature in the process of thermo electric conversion are systematically discussed.In the case of constant working condition and material,the refrigerating capacity is only related to G.With the gradual increase of G,the refrigerating capacity and coefficient increase first and then decrease.In the case of pursuing refrigerating capacity,the best G is about 0.13cm;In the case of pursuing refrigerating performance,the best G is about 0.25cm;In the case of constant other conditions,with the continuous increase of current,the refrigerating capacity increase first and then decrease and the cooling capacity and the current curve into a parabolic shape.When the current reaches about 6A,the thermoelectric refrigerator reaches the theoretical maximum cooling capacity operation condition;When the current reaches about 3A,the thermoelectric refrigerator is in the optimal cooling coefficient condition;the cooling capacity increases with the increase of the cold end temperature,which is proportional to the cold end temperature,so on the premise of meeting the cooling needs,The higher the cold end temperature is,the better the refrigeration performance is.Secondly,the human body liquid cooling suit is analyzed from the experimental point of view.The experimental results show that the maximum cooling capacity of TEC-12710 thermoelectric refrigeration sheet is between 22-28W,and the maximum cooling capacity of TEC-12715 is between 32-38W when the external environment temperature is 40? and the water inlet temperature is 25-30?.Based on the data,it needs three pieces of TEC-12710 thermoelectric refrigeration sheet to meet the needs or two pieces of TEC-12715 thermoelectric refrigeration sheet.In this way,the system will be much simpler and the refrigeration module is easy to disassemble.When the body liquid cooling suit works at 4-12V,the cooling capacity increases with the increase of voltage,but the performance coefficient decreases gradually.When the circulating water speed is 600ml/min,the cooling capacity is 39W corresponding to the working voltage is 12V.At the same input voltage,the cooling capacity decreases with the increase of ambient temperature and the cooling coefficient also decreases.Finally,a new type of wearable body cooling suit is designed by using the method of finite element numerical simulation,which avoids the heaviness and complexity of the liquid cooling suit.The simulation results are as follows:in the case of constant voltage,the average temperature of the cold end decreases first and then increases with the increase of the heat exchange area.When the heat exchange area is about 5cm,the average temperature of the cold end has a minimum value;the cooling capacity and heat dissipation capacity both tend to a constant value with the increase of the heat exchange area;with the increase of the heat exchange area,the performance coefficient of the thermoelectric refrigeration pair increases continuously.In order to meet the needs of human body heat dissipation,the maximum heat flow density of thermoelectric refrigeration is required to be above 100W/m2;From the perspective of economy,the bigger the performance coefficient of thermoelectric refrigeration is,the better it is,which requires a small voltage;In addition,considering the comfort of wearing,the average temperature should not be too big,so the voltage should be less than 0.04V as far as possible.Through the comprehensive consideration of each parameter,the optimal cooling area of human body is 7cm2.According to the shape of the human body,the designed thermoelectric refrigeration is connected in series to form a new human body cooling suit,which can be directly used for human body contact heat dissipation.