C. J. Hall
This study investigates the thermal efficiency of natural ventilation cycles, portraying them as analogous to the Joule or Brayton cycle, characterized by reversible adiabatic processes and constant pressure phases. The primary objective was to analyze two variations of the Joule cycle using dry air and humid air as working substances. The methodology involves evaluating the thermal efficiency in terms of the temperature differential in the downcast shaft compared to the absolute air temperature at the bottom. Results showed that the thermal efficiency increases dramatically with the mass rate of flow while maintaining constant enthalpy increases, although this initially appears to contravene the second law of thermodynamics. Further investigation with moist air revealed that thermal efficiency values were notably lower, approximating 20-40% of those observed with dry air, attributed to significant evaporation and condensation effects. Consequently, the study elucidates the complex relationships between mass flow rates, thermal efficiency, and thermodynamic principles governing natural ventilation systems in mining engineering contexts.
@article{6d88ee80-5f2d-44a9-a695-353ea4a96377,
title={The Thermal Efficiency of Some Natural Ventilation Cycles},
author={C. J. Hall},
year={2026},
language={en}
}TY - JOUR TI - The Thermal Efficiency of Some Natural Ventilation Cycles AU - C. J. Hall PY - 2026 LA - en ER -
Alain Vignes
This book provides a comprehensive overview of the fundamental principles of extractive metallurgy, with a specific focus on basic thermodynamics and
This paper addresses the challenge of assessing the feasibility of wind power plant projects at sites with insufficient or no local historic wind data
Important advances in electrochemical engineering technology over the last three decades have fostered the development of a lternative methods to alle