吸收式热变换器循环热力学模型及优化应用

THERMODYNAMIC MODEL OF ABSORPTION HEAT TRANSFORMER CYCLE AND ITS APPLICATION

建立了热源热容量有限时,综合考虑传热热阻、热源与环境的热漏以及循环内不可逆性时的实际四温位不可逆吸收式热变换器循环模型,导出了泵热率和泵热系数的一般特性关系;利用单效溴化锂吸收式热变换器机组的工程数值计算方法,与热力学模型预测结果进行了对比分析,佐证了所建立的热力学模型及导出的特性关系的正确性;并探讨了不同工况时的循环性能,以及通过减小循环内不可逆性、热源热漏和对换热器总传热面积进行优化分配后循环性能可能提高的幅度。

Considering synthetically the heat resistance hetween working fluid and the heat reservoir, the heat leakage between the heat reservoir and the environment, and the irreversibility of the internal cycle, the thermodynamic model of four-temperature-level irreversible absorption heat transformer with finite heat capacities of heat reservoirs was set up in this paper. The performance relation between the heating load and the cycle coefficient was derived. The model and the derived performance relation were confirmed by comparing the prediction results of the model with engineering analysis results for real absorption heat transformer. The cycle characteristics at different design points were discussed. The performance improvements of the cycle were obtained by reducing the heat leakage and internal irreversibility and by optimizing and distributing the total heat transferring area among the four heat exchangers.