Exergy Analysis of a Subcritical Refrigeration Cycle with an Improved Impulse Turbo Expander

Entropy

Zhenying Zhang¹ 

[1] Institute of Architecture and Civil Engineering, Hebei United University, Tangshan 063009, China

关键词: refrigeration cycle;    turbo expander;    optimum intermediate pressure;    coefficient of performance (COP);    exergy efficiency;   

DOI  :  10.3390/e16084392

来源: mdpi

【 摘 要 】

The impulse turbo expander (ITE) is employed to replace the throttling valve in the vapor compression refrigeration cycle to improve the system performance. An improved ITE and the corresponding cycle are presented. In the new cycle, the ITE not only acts as an expansion device with work extraction, but also serves as an economizer with vapor injection. An increase of 20% in the isentropic efficiency can be attained for the improved ITE compared with the conventional ITE owing to the reduction of the friction losses of the rotor. The performance of the novel cycle is investigated based on energy and exergy analysis. A correlation of the optimum intermediate pressure in terms of ITE efficiency is developed. The improved ITE cycle increases the exergy efficiency by 1.4%–6.1% over the conventional ITE cycle, 4.6%–8.3% over the economizer cycle and 7.2%–21.6% over the base cycle. Furthermore, the improved ITE cycle is also preferred due to its lower exergy loss.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland