热水供暖系统重力水头系数的计算与分析

Calculation and Analysis of Gravity Head Coefficient of Hot-water Heating System

提出用数学期望的方法确定热水供暖系统设计计算中所采用的重力水头系数。根据冬季室外温度的平均延续小时数,计算了我国部分城市供暖期重力水头系数的数学期望E[B]。结果表明:1)E[B]与地域有关;2)供暖系统的运行调节方式对E[B]有显著影响;3)在供回水温差相等的情况下,供回水温度对E[B]基本上无影响。给出了部分城市重力水头系数的推荐值。引入整个供暖期重力水头标准差检验了采用本文推荐的重力水头系数比采用现行规范中给出的重力水头系数更合理。

Mathematical expectationwas used to determine the gravity head coefficient adopted in the calculation and design of hot-water heating system. Based on the average duration （hours） of outdoor temperature in winter, the mathematical expectation E [ B ] of gravity head coefficient in some Chinese cities during heating period was calculated. The results showed that ： 1 ） E [ B ] is related to territory ; 2） the operation regulation method of heating system significantly influences E [ B ] ; 3 ） when the temperature difference between water supply and water return is equal, the temperature of water supply and water return generally has no influence on E [ B ]. The recommended gravity head coefficient in some cities was given. The standard deviation of gravity head throughout the heating period was introduced to test whether the recommended gravity head coefficient is more reasonable than that given in current specifications.