SUMMARY
Thermoelectric coolers (TECs) are widely used in various industries for precise temperature control, from electronics cooling to medical devices. When modeling TECs in only thermal analysis, the focus shifts to understanding thermal behavior without diving into the complexities of electrical and fluid simulations. That also allows to transfer the results to a subsequent structural analysis if needed. This streamlined approach not only reduces computational effort but also simplifies the workflow, making it easier to focus on key design aspects like thermal expansion, stress, and deformation. By avoiding the need for detailed electrical and fluid interactions, engineers can achieve faster results, reduce potential errors, and still gain valuable insights into the structural performance of TECs under different operating conditions.
In this blog entry we will show the basic aspects of TECs thermal behavior and following a simple example in Ansys Mechanical its effects will be included in a Thermal Analysis.
Thermoelectric Coolers (TECs)
This is an specific type of solid-state device that use the Peltier effect to transfer heat from one side of the device to the other. When an electric current flows through the TEC's thermoelectric materials, it causes one side to cool down (absorbing heat) and the other to heat up (dissipating heat). By reversing the current, the cooling and heating sides can switch. TECs are compact, reliable, and have no moving parts, making them ideal for precise temperature control in applications like electronics, medical devices, and laboratory equipment.
This model is completely doable in thermoelectrical analysis using the great coupled physics elements in Mechanical, but there are two arguments to avoid this kind of details in an only thermal oriented analysis.
- There are many small parts that involves material and geometry modeling and considerable mesh work.
- More degrees of freedom in the same analysis. Maybe more computing time.
Extracting the data from the TEC
The cooling capacity at TEC cold side is:
Assuming constant values for material properties including electric resistivity and for the hot junction temperature this equation becomes a straight line. Using the manufacturer's data is possible to extract this curve and the necessary values for simulation setup. 
,
and 
values are also usually included in the datasheets.
With an slope equals to m and a intercept equals to b and doing some algebra, we have the following:
Please note this 
value is not the material thermal conductivity. To obtain this lumped property from the data, you need to consider TEC dimensions: Area A and module height h.
Model construction
The model strategy is to apply a desired heat pumping load and solve for temperatures. Doing so, is easy to verify model setup using the actual device graph shown before.
Geometry:
The lumped model is created using three bodies with share topology definition to avoid contacts. Two ceramic layers have been added to facilitate model definition. Note geometrical dimensions A and h. This geometry also mimics actual TEC disposition.
Heat sources- Peltier effect:
The thermoelectric effect is considered adding a heat source in the interface between the element block and the ceramic in both sides. The heat magnitude is only a dummy value.
The heat generated at each source surface is calculated as:
Note this value is temperature dependent. That means we'll have two different heat values and this is the main source of the TEC heat pumping effect. We also need the current to establish the final value.
To implement this behavior, and APDL command object is inserted into the solution branch to create two temperature dependent tables and assign them to the sources object using Named Selection and replacing the dummy magnitude previously defined. The heat flux needs to be divided by the TEC area A. Here, the current value is entered as an argument to facilitate utilization.
Heat sources- Joule effect:
A volumetric heat source is defined just calculating:
Temperature -hot side:
It is strongly recommended to define at least one temperature in the model to avoid extremely high temperature values (This is equivalent to rigid body motion in structural analysis). The ambient temperature on the hot side is a good choice here, because this temperature is generally reported in datasheets.
Heat load:
The technical data is usually published at 
. To model this scenario we need to suppress this object. Otherwise, any desired value could be applied to the opposite face in the TEC.
Results
After solving the model is possible to extract temperature on the hot and cold surfaces to calculate the temperature difference. Using this value is possible to build the same graph presented for the actual TEC, this should match the data almost perfectly.
Also note how the time dependency is shown. In the Transient analysis is important to let enough time to stabilize the cooling device. Remember here the heat sources are temperature (result) dependent.
Conclusion
Modeling thermoelectric coolers (TECs) using a thermal-oriented approach provides a practical and efficient way to analyze their thermal behavior without delving into the complexities of electrical and fluid simulations. By leveraging manufacturer-provided data and simplifying the geometry, engineers can accurately replicate the TEC's thermal performance while reducing computational demands. The step-by-step process outlined in this blog demonstrates how to incorporate the thermoelectric effects into thermal analysis, ensuring reliable results that align with real-world performance. This streamlined approach not only facilitates faster analysis but also serves as a strong foundation for subsequent structural evaluations if required, making it a versatile and valuable tool for TEC modeling.
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