R134a-DMF吸收式制冷系统仿真分析

Simulation Analysis of R134a-DMF Absorption Refrigeration System

为解决R134a-DMF吸收式制冷系统吸收器出口出现制冷剂(R134a)气体问题,在原系统工艺流程中吸收器后面增加1个气液分离器进行改进。基于Aspen Plus软件,选取PENG-ROB物性方法,搭建R134a-DMF吸收式制冷仿真系统,对系统运行特性的影响因素进行分析。保持吸收器出口R134a质量分数为0.57、吸收温度为27℃,其余设定参数不变,发生温度变化范围70~100℃,蒸发温度变化范围13~21℃。当蒸发温度不变时,随着发生温度升高,蒸发器负荷逐渐增加,系统性能系数(COP)先增加后减小。当发生温度不变时,随着蒸发温度升高,蒸发器负荷逐渐增加,系统COP逐渐增加。保持发生温度85℃、蒸发温度13℃,其余设定参数不变,吸收温度变化范围25~35℃,吸收器出口R134a质量分数变化范围0.4~0.7。当吸收温度不变时,随着吸收器出口R134a质量分数增加,蒸发器负荷先增加后减小,系统COP先增加后保持不变。随着吸收器出口R134a质量分数增加,蒸发器负荷达到最大值,系统COP此时也达到最大值。不同的吸收温度条件下蒸发器负荷与系统COP的最大值不同,最大值所对应的吸收器出口R134a质量分数也不同,吸收温度降低,蒸发器负荷与系统COP的最大值增加,最大值所对应的吸收器出口R134a质量分数也增加。在蒸发器负荷下降过程中,当吸收器出口R134a质量分数不变时,随着吸收温度降低,蒸发器负荷逐渐增加。

In order to solve the problem of refrigerant(R134a)gas at the absorber outlet of the R134a DMF absorption refrigeration system,an improvement was made by adding a gas-liquid separator behind the absorber in the original system process for improvement.Based on the Aspen Plus software,the PENG-ROB physical property method was selected to build the R134a-DMF absorption refrigeration simulation system to analyze the influencing factors of the system's operating characteristics.When the mass fraction of R134a at the absorber outlet is kept at 0.57,the absorption temperature is kept at 27℃,and the other set parameters remain unchanged,the generation temperature varies from 70 to 100℃,and the evaporation temperature varies from 13 to 21℃.When the evaporation temperature remains constant,as the generation temperature increases,the evaporator load gradually increases,and the coefficient of performance(COP)of the system first increases and then decreases.When the generation temperature remains constant,as the evaporation temperature increases,the evaporator load gradually increases and the system COP gradually increases.When the generation temperature is kept at 85℃,the evaporation temperature is kept at 13℃,and the other set parameters remain unchanged,the absorption temperature varies from 25℃to 35℃,and the mass fraction of R134a at the absorber outlet varies from 0.4 to 0.7.When the absorption temperature remains constant,as the mass fraction of R134a at the absorber outlet increases,the evaporator load first increases and then decreases,and the system COP first increases and then remains unchanged.As the mass fraction of R134a at the absorber outlet increases,the evaporator load reaches its maximum value,and the system COP also reaches its maximum value at this time.Under different absorption temperature conditions,the evaporator load and the maximum value of system COP are different,and the mass fraction of R134a at the absorber outlet corresponding to the maximum value is also different.As the absorption temperature decreases,the maximum value of evaporator load and system COP increases,and the mass fraction of R134a at the absorber outlet corresponding to the maximum value also increases.During the load drop of the evaporator,when the mass fraction of R134a at the absorber outlet remains constant,the evaporator load gradually increases as the absorption temperature decreases.