*3.3. Relative Error Analysis*

In order to assess the quality of results obtained using the reduced DPL model, an error analysis was carried out. Figure 7 shows a comparison of relative error values calculated between the reduced and non-reduced DPL model outputs for three selected points of time, similar to those investigated in the previous subsection. For all the mentioned time points, the relative error values in relation to each discretization mesh nodes were analyzed.

**Figure 7.** Comparison of relative error values in relation to a number of discretization mesh node for selected time points (t = 12.023 ns, t = 18.197 ns, and t = 2 μs).

The maximum relative error value did not exceed a level of 5%, which confirms good accuracy of the reduced DPL model results. Moreover, the relative error decreased with an increase in the value of the investigated time points. For example, for higher observed temperature rise values, the relative error is at a level of 1%–1.35%. Furthermore, for steady state, a maximum relative error value is approximately equal to 0.01%. Such a small error value can be neglected. The decrease of the relative error value over time also suggests a convergence of the proposed approach.
