Thermoelectric coolers and generators are often used as reliable energy converters in a variety of applications. For design considerations, it is investable to establish an effective methodology to simulate the TEC/TEG performance within the cooling/generating system constraints. For this purpose, firstly, three approaches are established to find the internal parameters of a given thermoelectric module. For these procedures, simulated pumping powers are in the sequence of method III < method II < method I for each temperature difference conditions. Hence, the good estimation way of the simulated data is by averaging the results of these three methods. Finally, the design approach is implemented to freezing chuck designs. Temperature distributions on the top surface of chuck are measured by experiments for comparisons. It shows that the established TEC model is applicable to obtain accuracy temperature fields for the purpose of freezing chuck design.