Figure 5. Measurement of heat transfer rate across terminals.

(a) Measured heat dissipated in the fixed terminal (Q_fix) versus temperature of the moving terminal (T_mov). Each set of Q_fix and all other related measurements were conducted while the fixed terminal temperature (T_fix) was kept at a constant value. The two data sets correspond to two temperature values for T_fix: 375 and 530 K. (b) Measured heat dissipated in the moving terminal (Q_mov) versus T_mov, for two different T_fix values of 375 and 530 K. Uncertainties were not plotted in a and b since they were low, less than 0.16% and 0.29% for Q_fix and Q_mov, respectively. (c) heat transfer from the fixed to the moving terminal (Q_fix-mov) versus T_mov for the two different T_fix values. The dashed lines illustrate the heat transfer across terminals in forward and reverse directions for the set of temperature of 375 and 530 K. Uncertainties in the heat transfer rates are represented by the shaded area around the data points, with a maximum value of 2.74 × 10⁻⁵ W. (d) Heat losses from the moving terminal (Q_loss,mov) versus T_mov, for the two different T_fix values. Uncertainties were not plotted here as they were low, less than 3.89 × 10⁻⁵ W. Uncertainty was calculated based on the technique reported in ref. 36, more details in Supplementary Information.