Study And Application On Wearable Technology For Thermal Comfort Of Human Body

Thermal comfort system belongs to a kind of wearable thermal micro-system. It can provide cooling or heating output for human body under variable environmental temperature, and then regulate the energy balance so as to guarantee the thermal comfort state. Its main application value lies in three aspects: 1. Protects human body in the extreme temperature; 2. Assists human body to reach the thermal comfort as a wearable micro-temperature condition system in outdoors; 3. Replaces traditional Heating Ventilation and Air conditioning in order to save energy. Based on above considerations, this thesis is dedicated to conduct the theoretical research and practical application on the thermal comfort system as follows:Firstly, the standards of thermal comfort based on heat transfer theory was studied and calculation formula for the system output energy was derived. The thermal comfort evaluation index PMV and PPD were introduced to evaluate thermal the environment with different variables as: air temperature and relative humidity, metabolic rate, dress heat resistance, and wind speed.Secondly, a theoretical model of thermal comfort for feet was established. And the Fluent software was used to characterize the bio-heat transfer in feet at the normal and extreme temperature based on the classical Pennes model. A feet thermal comfort system was designed according to low temperature environment, and then the system with infrared thermometer and thermocouple data acquisition was adopted for the test.Thirdly, aiming to serve for field soldiers, a fan cooling system for modern digital soldier helmet. Numerical simulation method was applied to study the air flow rate and channels in the helmet, and then the experimental means were performed to verify the simulation results.Finally, focusing on the problem of power system, the solar energy driving system, which is used to cool the human body at the high temperature weather, was designed based on micro-fans array cooling and semiconductor refrigeration chip.