Effect of an Internal Heat Exchanger on Performance of theTranscritical Carbon Dioxide Refrigeration Cycle withan Expander

Entropy

Lili Tian¹  Zhenying Zhang²  Yanhua Chen²  Lirui Tong² 

[1] Department of Foreign Languages, Tangshan College, Tangshan 063000, China;Institute of Architecture and Civil Engineering, Hebei United University, Tangshan 063009, China;

关键词: transcritical refrigeration cycle;    expander;    internal heat exchanger;    carbon dioxide;   

DOI  :  10.3390/e16115919

来源: DOAJ

【 摘 要 】

The effect of the internal heat exchanger (IHE) on the performance of the transcritical carbon dioxide refrigeration cycle with an expander is analyzed theoretically on the basis of the first and second laws of thermodynamics. The possible parameters affecting system efficiency such as heat rejection pressure, gas cooler outlet temperature, evaporating temperature, expander isentropic efficiency and IHE effectiveness are investigated. It is found that the IHE addition in the carbon dioxide refrigeration cycle with an expander increases the specific cooling capacity and compression work, and decreases the optimum heat rejection pressure and the expander output power. An IHE addition does not always improve the system performance in the refrigeration cycle with an expander. The throttle valve cycle with IHE provides a 5.6% to 17% increase in maximum COP compared to that of the basic cycle. For the ideal expander cycle with IHE, the maximum COP is approximately 12.3% to 16.1% lower than the maximum COP of the cycle without IHE. Whether the energy efficiency of the cycle by IHE can be improved depends on the isentropic efficiency level of the expander. The use of IHE is only applicable in the cases of lower expander isentropic efficiencies or higher gas cooler exit temperatures for the refrigeration cycle with an expander from the view of energy efficiency.

【 授权许可】

Unknown