高温LiBr双吸收式热变换器分析

Exergy analysis of a high temperature water-lithium bromide double effect absorption heat transformer

基于热力学第一、第二定律建立了高温LiBr双吸收式热变换器热力学模型.模型考察了系统各操作温度、循环倍率(Rf)、溶液热交换器换热效率(Ef)和系统温升(Tgl)对系统性能(ECOP)、主要部件损失(Ed)和总损失(Et)的影响.结果表明,吸收器和再生器是整个系统损失最大的部件;ECOP随着再生温度、蒸发温度、吸收-蒸发温度和溶液热交换器换热效率增加而增加;随着吸收温度、冷凝温度、循环倍率和系统温升增加而减小.为了获得较好的系统性能,系统温升不应该超过72K.

A thermodynamic model for a high temperature double effect absorption heat transformer based on the first and the second laws of thermodynamics is presented. The model takes account for the effect of operating temperatures, flow ratio （Rf）, effectiveness of solution heat exchanger （El） and gross temperature lift （Tsl） on the exergy coefficient of performance （ECOP）, exergy destruction in each component （Ea） and the total exergy destruction （Et）. The experimental results indicate that the absorber and the generator are the largest exergy destruction components in the whole system. In particular, ECOP increases with the generator, evaporator, absorber-evaporator temperatures, and Ef increasing and decreases with absorption and condensing temperatures, Rf and T~ increasing. Finally, the Tgt should be not over 72 K for improving the performance of the system.