H_2O/LiBr双吸收式热变换器系统多目标参数优化

Multi-objective optimization of H_2O/LiBr double absorption heat transformer

以双吸收式热变换器作为研究对象,综合考虑系统总传热面积Atot、热效率COP、总损失I和热源输入Exin,通过线性加权法建立了以Atot/COP和I/Exin为目标函数的多目标评价模型。利用多目标模型对系统进行参数优化的结果表明,多目标评价模型能同时考虑多个优化目标,相比单一目标更为合理;在给定的工况范围内,存在最优的发生温度、蒸发温度、吸收温度、吸收/蒸发温度以及第一溶液热交换器效能,使多目标函数最小;尽可能降低冷凝温度和提高第一溶液热交换器效能有利于提高系统的整体性能。

A mathematic model of the double absorption heat transformer is built in this paper. Taking total heat exchanger area（Atot）, coefficient of performance（COP）, total exergy destruction（I） and exergy input（Exin） into consideration, a multi-objective function that incorporates two sub-objective functions, i.e. first objective function Atot/COP and second objective function I/Exin, is developed by the method of linear weighting. Based on the multi-objective function, a parameter optimization has been carried out. The result shows that, within the given working conditions, there exist an optimal generator temperature, evaporator temperature, absorber/evaporator temperature, absorber temperature and the second solution heat exchanger effectiveness minimizing the multi-objective function values,whereas the condenser temperature and first solution heat exchanger effectiveness show monotonic,and the decrease in condenser temperature or increase in the first solution heat exchanger effectiveness can improve the system performance.