Experimental Study Of The Effect Of Contact Thermal Resistance On The Performance Of Thermoelectric Generator

Transportation vehicles powered by internal combustion engines are one of the significant causes of the energy crisis and environmental pollution.For example,in cars,viewing from the energy balance perspective,approximately 30-45% of the fuel combustion energy is released into air as exhaust.Recycling and reusing the exhaust heat energy released from automobiles can not only improve the energy efficiency,but also reduce environmental pollution.The thermoelectric generator(TEG)may offer converter stable performance during its operation,no noise,and long life,which is a suitable heat recovery system for new green technology.Therefore,increasing attention has been paid to thermoelectric power generation technology for thermoelectric energy conversion by using semiconductor materialsAlthough the thermoelectric generator has a simple design,its low efficiency limits the practical application of the devices.The most critical parameters influencing the device output power is the Figure of Merit,operating temperature ratio,and external load.The Figure of Merit can be improved through increasing the Seebeck current while lowering the thermal conductivity of the device active parts such as pins.Operating conditions depend on the source and sink temperatures where thermoelectric device operates in between.External load is associated with the electrical resistance of the external device.The objective of this study is to reveal the effect of thermal contact resistance on the performance of TEG;the effects of the interface material,heating flux and loading pressure on the performance of TEG was measured experimentally and compared.The experimental results showed that the performance of TEG was enhanced by adding interface material and the increasing loading pressure.Compared to without the thermal grease at the contact interface,the performance of TEG with thermal grease at the contact interface is much higher than when it is not;The maximum output power and the conversion efficiency increased.With the addition of the thermal grease,the loading pressure increased,the contact resistance between the thermoelectric modules and hot and cold source surfaces reduced,and the actual temperature difference increased across the thermoelectric module,the maximum power output and conversion efficiency of TEG were improved respectively.At the same loading pressure,the thermal resistance of the thermoelectric module improved with the increasing average temperature,and the proportion of the thermal resistance of the thermoelectric module and the total thermal resistance increased.The actual temperature difference at both sides of the thermoelectric module increased,and the maximum output power and conversion efficiency of TEG increased.