Design And Research Of Medical Thermostat Based On Thermoelectric Cooler

The storage and transportation of medical examination specimens are inseparable from the medical refrigerator.The shortcomings of the traditional medical refrigerators are bulky and inaccurate in temperature control,which lead to the instability of thetemperatureof specimens and affect the examinationresults.In this thesis,thecommercial thermoelectric cooler(TEC)is used as the core component,while Arduino microcontroller is selected as the main control unit.Bluetooth is used as the wirelesscommunication mode.A medical thermostat is designed and implementedforthe storage and transportation of medical specimens,with the advantages of compact dimensions,light weight,supporting thermostatic coolingand heating operations as well as remote control.The software components include a We Chat mini program for mobile devices and the upper computer software for PCs,which can meet the needs of the thermostat in different scenarios.Ingeneral,all the work in this thesis could be divided into fourparts as follows:(1)An overview of the advancementsin domestic and international medical refrigeration and semiconductor refrigeration technology isintroduced.Subsequently,the limitations of the standard medical examination specimens in the process of transport are outlined.Finally,anovel medical thermostatemploying TEC as energy transfer device is proposed,combining with the working principle and theadvantages of TEC;(2)The overall design specifications of the medical thermostat are establishedbased on the actual usage requirements.TEC selection,heat sink selection and the structural design of the specimen container are carried out.The thermoelectric effect of TEC is analyzed theoretically.Heat transfer theoretical analysis and temperature field simulation analysis are carried out for the key parts of the thermostat,and the effectiveness of the thermostat is verifiedwiththe simulation results;(3)The temperature regulation system of thermostat is designed and implementedunder the condition that the thermostat has the ability of cooling and heating.Withinthe hardwarecomponents,the Arduino microcontroller is selected as the main control unit.ADN8835 is selected as the TEC driver chip.A temperature control circuit,intergrating an analog PID circuit is established to realize both heating and cooling functions.In the aspect of human machine interface,keys and an OLED screen are selected to adjust and display the temperature respectively.Bluetooth is selected as the wireless communication unit.In terms of softwareaspects,a We Chat mini program is developed,which communicates with the thermostat system through Bluetooth.Additionally,an upper computer software for PCsbuilt on Qt framework is developed,which can realize the monitoring and control of thermostat through the serial port;(4)An experimental test platform is established to evaluate the coolingand heating performance of the medical thermostat.The experimental results demonstrate that the temperature deviationbetween the target temperature and the setting temperature is within 1 ℃,when the system reaches steady state.The research results of this thesis show that all functions of the thermostat can meet the initialdesign requirements.In addition,the thermostat can not only meet the constant temperature storage and transportation of medical examinationspecimens,but also provide a new idea for the development of medical thermostat technology.