CTHP循环系统有限时间热力学模型及分析

Finite Time Thermodynamic Model and Analysis of CTHP Cycle System

为解决凝汽电厂热电联产改造过程中因需使用减温减压器降温减压而造成的高品位能量的浪费问题,本文以将凝汽电厂减温减压器中的高品位能量利用起来,从而回收电厂循环冷却水的余热的汽机热泵联合循环(CTHP)系统作为研究对象,基于有限时间热力学的方法,以系统获得最佳供热能力为目标,以最小总热导率为约束条件,通过建立CTHP循环系统有限时间热力学模型,计算分析了CTHP循环系统热力学参数的变化规律,以及最佳供热率的相关影响因素。结果表明,汽机低温侧蒸汽出口温度及性能参数a_2、a_3是对系统无量纲供热率最低的影响因素,该结论为CTHP循环系统设计及实际运行时的性能优化提供理论依据。

The temperature and pressure combined reducer is used to reduce the temperature and pressure in the retrofit cogeneration of condensing power plant,which is a waste of the high grade energy. To solve this problem,the high grade energy in the temperature and pressure combined reducer should be used step by step and the waste heat of the circulating cooling water in the power plant should be recovered.This paper focuses on related factors of optimum heating rate of CTHP cycle system by establishing CTHP finite time thermodynamic model and limiting thermal conductivity. The result shows that the steam outlet temperature and performance parameters a2 and a3 at the low temperature side of the steam turbine have the most important impact on the dimensionless heating rate of the system,which is a guidance of the practical application and improvement of system performance.