内可逆Carnot制冷机和热泵输出率密度分析与优化

Analysis and Optimization of Output Load Density for Endoreversible Carnot Refrigerator and Heat Pump

以内可逆Carnot循环的输出率密度(对循环最大体积平均的循环输出率),即Carnot制冷机的制冷率密度和Carnot热泵的供热率密度作为热力性能指标,分别对内可逆Carnot制冷机和热泵进行分析与优化,导出了最佳换热器面积分配关系式,通过数值计算分析了热源温比对输出率密度与性能系数关系的影响。结果表明,考虑循环体积后,Carnot制冷机的制冷率密度与制冷系数特性关系呈抛物线型,这与传统分析中单调递减的制冷率与制冷系数特性关系完全不同;Carnot热泵的供热率密度与供热系数特性关系呈抛物线型,也与传统分析得到的单调递减的供热率与供热系数特性关系不同。

The performance analysis and optimization of endoreversible Carnot refrigerator and heat pump was carried out by taking the output load density （the ratio of output load to the maximum specific volume in the cycle）,i, e. the cooling load density and the heating load density as the optimization objective. The analytical expression for the opti- mal allocation of heat-exchanger area was derived. The effect of heat reservoir temperature ratio on the output load density versus coefficient of performance （COP） was analyzed with detailed numerical examples. The results show that the characteristic curve of cooling load density versus COP is a parabolic-like one, dramatically different from the monotonic curve of cooling load versus C（）P; the characteristic curve of heating load density versus COP is also a parabolic-like one, different from the monotonic curve of heating load versus COP.