集中供热蒸汽管网系统的热效率与火用效率综合分析OA

A scientific assessment of the energy efficiency of long-distance steam pipelines in central heating systems requires an evaluation framework that considers both the quantity and the quality of energy.This study establishes an analytical model for steam pipeline transport,coupling equations for pressure drop,temperature drop,energy bal-ance,and exergy balance,to systematically analyze the influence of key parameters—namely initial steam tempera-ture,initial pressure,mass flow rate,and insulation thickness—on thermal efficiency and exergy efficiency.The re-sults show that the two efficiency metrics respond significantly differently to these parameters.Compared to thermal ef-ficiency,exergy efficiency provides a more comprehensive reflection of the loss of energy quality due to heat dissipa-tion and flow irreversibility,exhibiting greater sensitivity to parameter variations.Specifically,an increase in the ini-tial steam temperature reduces both thermal efficiency and exergy efficiency,but the decline in exergy efficiency is more pronounced.Raising the initial pressure substantially improves exergy efficiency by significantly reducing flow ir-reversibility losses,while thermal efficiency decreases slightly due to a reduction in specific enthalpy.exergy efficien-cy exhibits a non-monotonic,initially increasing then decreasing trend with increasing steam flow rate,presenting an optimal flow point,whereas thermal efficiency increases monotonically.Increasing the insulation thickness effectively improves both thermal efficiency and exergy efficiency,with the benefit to exergy efficiency being more significant.This analysis provides a theoretical basis,integrating both the quantity and quality of energy,for the refined design and energy-efficient operation of long-distance steam heating networks.