Abstract : A model based on one-dimension steady-state heat transfer was developed, to calculate the generated current, voltage and power of the TEG system. Using the Finite Element Method (FEM) and the temperature dependent conductivity, resistivity, Seebeck coefficient, and Thomson coefficient, the output current and voltage were compared for the FEM and the Average Method (the average value between the hot and cold surface). The FEM and the Average Method showed different values, especially at high temperature differences ∆T above 80 K for the current and above 130 K for the voltage. The effect of changing the load resistor was studied, proving that the maximum current can be obtained when the load resistor is equal to the internal resistance of the TEG. In addition, the model is used to find the optimum combination of size and length of the p-n materials (thermocouple). The result shows that larger area and the shorter length for the design of the thermocouple, gives the maximum power. Parallel to the modelling, the effect of the size of the applied heat system on the current and voltage was investigated experimentally, showing the effect of the size of the heated area on the current linear fitting. It is found that the larger the size the better linear fitting.