## 3 Results  
### Influence of TEC Current and Heat Sink Type on the Heat Flux and Electric Power  
The results of the research on the effect of the TEC current on the amount of heat flux transferred by the FTE1-01 flexible module and on the electric power supplied to it, depending on the heat sink used in isothermal conditions (T = 35 \({}^{\circ}\)C), are shown in the graphs below (Figures 8 and 9, respectively).  
On the basis of Figure 8, it can be concluded that the dependence of the heat flux on the TEC current is close to linear, except for the EP variant (flexible module with the polymer TEGway heat sink). The performed statistical analysis showed that only in the case of the EM variant (i.e., with the use of the metal heat sink), the effect of increasing the TEC current from 0.1 to 0.25 A was statistically significant. The obtained test results also indicate that the type of heat sink used has a significant impact on the obtained value of the heat flux transferred by the module from the heating plate of the \"skin model.\" Elements that use the evaporation effect have significantly higher efficiencies. The metal heat sink, which transfers heat to the environment almost exclusively by convection (the radiation mechanism being negligible at the temperatures applied), is much less effective. The observed differences between these variants were statistically significant for each of the analyzed current values. The self-made heat sink with SAP turned out to be less effective than the polymer one provided by TEGway. However, as the research has shown, when assessing heat sinks, the durability of their properties over time should also be taken into account. The TEGway heat sink stopped absorbing moisture after several dozen uses and, consequently, stopped fulfilling its intended function.  
Figure 7: System composed of the flexible TEC and the metal heat sink inside the climatic chamber.  
As a result of the laboratory tests, the characteristic of the electric power consumed by the FTE1 01 module was also determined as a function of the module supply current (Figure 9). The measurement uncertainty of this power calculated according to Equations (5) and (6) was between 2.7% and 3.2%.  
This characteristic does not depend on the heat sink used, which is in line with theoretical predictions: it should result only from the electrical properties of the thermoelectric module. This characteristic is parabola-shaped, which indicates the resistive nature of the module according to [PERSON]'s law:  
\[\mathrm{P_{e}=I^{2}\times R}, \tag{6}\]  
where:  
Figure 8: Heat flux as a function of TEC current, for different heat sink elements, in isothermal conditions for T = 35 \({}^{\circ}\)C: error bars correspond to standard deviation; _“*\"_ marks the statistically significant difference for \(p\) = 0.05.  
Figure 9: Electric power as a function of TEC current for different heat sink elements, in isothermal conditions for T = 35 \({}^{\circ}\)C (yellow dashed line, regression curve)  
P\({}_{\rm e}\)--electric power, W; I--TEG module current, A; R--TEG module resistance, \(\Omega\).  
The regression curve in the diagram (Figure 9) has a coefficient at a power of 2 equal to 4.80 \(\Omega\), which is the module resistance. The knowledge of this value will allow to determine the required parameters of the power supply and the control system in the future if this module is selected for the construction of the cooling system.