溴化锂吸收式热泵的动态建模及运行特性分析

Analysis of Dynamic of Modeling and Operation Characteristics of LiBr Absorption Heat Pump

为充分挖掘吸收式热泵的动态运行特性,考虑各部件存量工质的储热特性建立考虑传质和分布参数的溴化锂吸收式热泵动态仿真模型。在机组各设备存量工质质量不同的情况下,分析了热源工质进口温度的提升对冷却水和冷媒水出口温度的动态影响及系统的热惯性特征,同时在热源工质进口、冷却水进口和冷媒水进口温度变化的情况下,分析了系统的性能系数(Coefficient of Performance,COP)变化特性及结晶风险变化特性。结果表明:该模型能准确地模拟吸收式热泵的稳态特性和动态特性;机组的热惯性主要与机组内各设备中的存量溶液质量有关;热源工质入口温度的上限受到系统COP及结晶风险的双重影响;冷却水入口温度的下降可增大系统COP,其下限受到结晶风险的限制;冷媒水入口温度的上限不受结晶特性限制;主要受用户侧的用能需求限制。

In order to fully dig out the dynamic operation characteristics of absorption heat pump,considering the heat storage characteristics of stock working medium of each component,a dynamic simulation model of lithium bromide absorption heat pump considering mass transfer and distribution parameters is established.Under the condition that the mass of stock working medium in each equipment of the unit is different,the influence of the increase of the inlet temperature of the heat source working medium on the dynamic change of the outlet temperatures of cooling water and refrigerant water is analyzed,and the thermal inertia characteristics of the system are studied.At the same time,the changing features of system coefficient of performance(COP)and crystallization risk are analyzed under the changes of the inlet temperature of the heat source working medium,the inlet temperature of cooling water and the inlet temperature of refrigerant water.The results show that this model can accurately simulate the steady-state and dynamic characteristics of the absorption heat pump;the thermal inertia of the unit is mainly related to the mass of the stock solution in each equipment of the unit;the upper limit of the inlet temperature of the heat source working medium is affected by the system COP and crystallization risk;the decrease of the inlet temperature of the cooling water can increase the COP of the system,its lower limit is limited by crystallization risk;and the upper limit of inlet temperature of refrigerant water is not limited by crystallization characteristics,which is mainly limited by the energy demand on the user side.