IAPWS95 uses the second law of thermodynamics (η=1-T1/T2) to calculate the specific heat of water vapor, with theoretical and experimental deviations of 5-15%.

NOTES：

1. The figure above is IAPWS95's calculation of the specific heat of water under high pressure and the experimental deviation rate of 5-15%.

2, the proportion of specific heat determined by the second law of thermodynamics is not large, and the actual deviation rate of the second law of thermodynamics is much larger than 5-15%.

3, at high pressure, the second law of thermodynamics does not hold, and it does not hold at low pressure. The reason "η=1-T1/T2" includes only the temperature (molecular kinetic energy) and does not take into account the potential energy of the molecular interaction.

4，Scientists have long known that using the second law of thermodynamics (η=1-T1/T2) to calculate the thermal properties of working media does not agree with experiments. They favour and protect the second law of thermodynamics, damaging the reputation of the scientific community.