Is zeotropic working fluid a promising option for organic Rankine cycle: A quantitative evaluation based on literature data

The development of alternative working fluids has become a difficult and never-ending task, and thus driven a tremendous progress of the organic Rankine cycle (ORC) technology. In the past 25 years, the promotion of zeotropic working fluid has provided a new opportunity to further improve the performance of ORC. However, a critical performance comparison between zeotropic mixtures and pure working fluids in ORC systems is still rare, due to a lack of reasonable framework of comparative analysis and confused original data. Particularly, it is controversial whether zeotropic mixtures are promising alternatives when considering economic factors. In such a situation, a quantitative performance evaluation of zeotropic mixtures is necessary to quickly understand the current research progress and assess new research results. This paper presents a data-based evaluation of comprehensive performance of zeotropic mixtures. The available data is collected, screened, and classified from 361 published papers. 1312 available data of thermodynamic performance calculation and application aspects is obtained from 94 papers for in-depth analysis. The comparison between theoretical calculation and application shows that organic Rankine cycle using zeotropic working fluids have potential for wide application. However, there are many problems need to be solved in theory and application, such as thermodynamic cycle construction, key device design, composition shift, dynamic performance and control strategy and so on.

Automated summary

The development of zeotropic working fluids has provided new opportunities to improve the performance of ORC technology, but challenges remain in theory and application that need to be addressed.