An effective method of evaluating the device-level thermophysical properties and performance of micro-thermoelectric coolers

•A three-dimensional numerical model of micro thermoelectric cooler is developed.•The joint impact of boundary and size effects on TE properties is discussed.•A comparison between the numerical and reported experimental results is conducted.•The impact of interfacial resistances on cooling performance of TEC is discussed.•The cooling capacity and optimal working condition of the micro TEC is analyzed.