Thermoelectric Cooling

Flow Simulation has the ability to model the work of a thermoelectric cooler (TEC), also known as Peltier element.

The device used in this example has been developed for active cooling of an infrared focal plane array detector used during the Mars space mission (see Ref. 28).

According to the hardware requirements, the cooler (see Figure 1 and Figure 2) has the following dimensions: thickness of 4.8 mm, cold side of 8x8 mm2 and hot side of 12x12 mm2. It was built up of three layers of semiconductor pellets made of (Bi,Sb)2(Se,Te)3-based material. The cooler was designed to work at temperatures of hot surface in the range of 120-180 K and to provide the temperature drop of more than 30 K between its surfaces.

Figure 1. Structure of the thermoelectric cooler

Figure 2. The thermoelectric module test setup.

To solve the engineering problem using Flow Simulation, the cooler has been modeled by a truncated pyramidal body with fixed temperature (Th) on the hot surface and given heat flow (Qc) on the cold surface (see Figure 3).

Figure 3. The model geometry: (1) TEC, (2) part of infrared focal plane array detector, (3) part of heat sink.

The TEC characteristics necessary for the modeling, i.e. temperature dependencies of the maximum pumped heat, maximum temperature drop, maximum current strength and maximum voltage, were represented in the Flow Simulation Engineering Database as a linear interpolation between the values taken from Ref. 28 (see Figure 4).

Figure 4. The TEC’s characteristics in the Engineering Database.

As it can be seen on Figure 5, the temperature drop between the cooler’s hot and cold surfaces in dependence of current agrees well with the experimental data.

Figure 5. ΔT as a function of current under various Th.

The dependency of ΔT against heat flow under various Th (see Figure 6) is also in a good agreement with the performance data, as well as the coefficient of performance COP (see Figure 7) defined as follows:

where Pin is the cooler’s power consumption, and Qc and Qh are the heat flows on the cold and hot faces, respectively.

Figure 6. ΔT as a function of heat flow under various Th.

Figure 7. COP as a function of ΔT under various Th.

Finally, we may conclude that Flow Simulation reproduces thermal characteristics of the thermoelectric coolers at various currents and temperatures with good precision.