Filtered k-Integral Approach for Regional Enthalpy/Entropy Flow: Experimental Validation with NIST Data

A generalized filtered k-integral framework is presented and experimentally validated for the regional calculation of enthalpy and entropy flows in thermodynamic systems. Unlike classical integration, this method enables localized, weighted, or phase-specific evaluation of thermodynamic quantities. Using the NIST Chemistry WebBook’s open data, we demonstrate how filtered k-integrals allow targeted enthalpy and entropy analysis for selected physical states (e.g., the supercritical phase), revealing high-resolution, phase-specific behaviors that are invisible to standard integration methods. The results confirm that filtered k-integrals extend classical thermodynamic analysis to modern, complex problems.The author acknowledges the use of OpenAI’s language model for assistance in drafting certain sections of this workl