Abstract
The study investigates the comprehensive effects of superheat and internal heat exchanger (IHX) on the thermo-economic performance of organic Rankine cycle (ORC). Exergy efficiency, net power output, and electricity production cost (EPC) are compared based on the working fluid properties and heat sources. The results indicate that under a lower heat source temperature and load, exergy efficiency of IHX-ORC does not always exceed that of simple ORC (S-ORC) when EPC is selected as an objective function, and IHX-ORC exhibits a worse economic performance than S-ORC for all fluids (R161, R1234ze, R152a, cyclopropane, butane, R123, cyclopentane, heptane, and cyclohexane). However, IHX-ORC with dry fluid achieves a better thermo-economic performance than that with wet fluid when the heat source temperature and load increase to a high level. The EPC of IHX-ORC is close to that of S-ORC with the increase in heat source temperature and load, and thus, IHX-ORC exhibits approximately 10–17% higher thermal efficiency and 5–10% higher exergy efficiency than those of S-ORC. With respect to butane and R123, the net power output exhibits approximately 22.5% and 23.5% growth, respectively. In order to evaluate the feasibility of IHX-ORC, a judgement indicator [α > 1.90625 + 0.4258ξ] with respect to six factors is proposed.
Original language | English |
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Pages (from-to) | 482-495 |
Number of pages | 14 |
Journal | Energy |
Volume | 159 |
Early online date | 27 Jun 2018 |
DOIs | |
Publication status | Published - 15 Sept 2018 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2018 Elsevier Ltd
Funding
The study is supported by National Natural Science Foundation of China (No. 51576019) and Fundamental Research Funds for the Central Universities (No. 2018CDXYDL0001). The author, Cheng Zhang, would like to acknowledge financial support from the Chinese Scholarship Council (CSC).
Keywords
- Evaporator superheat
- Heat sources
- Internal heat exchanger
- Organic Rankine cycle
- Thermo-economic analysis
- Working fluids