R1233zd(E)高温热泵用卧式冷凝器的换热动态模拟

Dynamic simulation of horizontal condenser of R1233zd(E)high temperature heat pump

建立了一种R1233zd(E)卧式冷凝器的动态仿真模型,其相比于稳态模型在预测系统运行特性方面具有明显优势。详细介绍了建模所用控制方程、离散方法、运算逻辑等,模型可以计算出冷凝器在每一时间步长下,每一个控制体内制冷剂、管壁、冷却水的状态参数。由于模型涵盖了换热管的几何参数,因此改变几何参数可以模拟采用不同换热管结构对冷凝器性能的影响,比较了采用不同齿距的换热管对换热器内部相区分布、换热量、出水温度的影响。模拟结果得出,采用齿距为1.3 mm的低肋管时,出水温度较光管提升1.5℃以上,达到稳定输出的时间提前1 min以上,换热量提升2.3倍。R1233zd(E)作为新型环保工质,缺乏相关的热泵模型研究,因此搭建该冷凝器模型是完成R1233zd(E)高温热泵模型的重要基础。

This paper presents the dynamic heat transfer model of a R1233zd(E)horizontal condenser.Compared with the steady-state model,the dynamic model has obvious advantages in predicting the system operating performance and understanding the working principle.This article introduces the equations,discrete methods and model calculation logic in detail.From the results,the state parameters of the refrigerant,tube wall,and cooling water in every control volume of the condenser at each time step can be obtained.Since the model covers the geometric parameters of the heat exchange tubes,the geometric parameters variation of the heat exchange tubes can cause the great effect of heat transfer performance of the condenser.The study compares the phase area,heating capacity and output water temperature under different heat exchange tubes.For the results,when a low-rib heat exchange tube with the fin pitch of 1.3 mm is used,the temperature of the outlet water is increased by more than 1.5℃than that of the light tube,the time to reach stable output is more than 1 minute earlier,and the heating capacity is increased by 2.3 times.R1233zd(E)acts as a new environmental protection working fluid,and there are not too much studies about the heat pump model.So this condenser model is an important basis for the further research of R1233zd(E)high temperature heat pump.