Influence study of bottom cycle ratios and superheat for vessels waste heat cascade recovery based on TEG-ORC combined cycle system employing R245fa

ABSTRACT

The vessel’s waste heat has the characteristics of a large temperature gradient, huge recoverable volumes, and various properties. TEG-ORC combined cycle is a promising method for multiple vessels waste heat cascade utilization. Keeping the evaporation pressure at 0.7Mpa, R245fa of low toxicity and environmental friendly is employed for the research under the conditions of different bottom cycle ratios(₣) and superheating. The interaction between essential parameters and system performance is explored. As the ₣ gets larger, the system net power output (W_net), the system thermal efficiency (η_s) and the waste heat utilization of main engine flue gas (f_g) gradually increase, the power-production cost (C_g) of the system gradually decreases. When the degree of superheat increases from 3.36K to 9.23K, the output power of the expander increases synchronously. The results show that superheating improves the combined cycle W_net and f_g while reducing theC_g. The stability and safety of the ORC unit are further enhanced by expanding the ₣. When the ₣ is 0.885 and superheat is 11.28 K, W_net is 965.18 W, η_s is 8.74%, and the C_g of the system is 0.5363 $ k Wh⁻¹, and the rate of f_g is 85.07%.

KEYWORDS:

• Vessels waste heat
• vessels energy efficiency
• TEG-ORC combined cycle
• bottom cycle ratios
• superheat

Disclosure statement

No potential conflict of interest was reported by the author(s).

Credit author statement

Changxin Liu: Conceptualization, Writing-Review & Editing, Formal analysis

Huaan Li: Methodology, Writing-Original Draft, Validation, Data Curation

ShanshanYu: Software, Resources, Investigation

Guanghao Qu: Visualization, Investigation

Wenxiang Ye: Data Curation

Zhitao Han: Supervision

Minyi Xu: Data Curation, Supervision

Xinxiang Pan: Project administration

Additional information

Funding

This work was supported by the Fundamental Research Funds for the National Key R & D Project from Minister of Science and Technology [2021YFA1201604], the Central Universities [Grants 3132019330], the National Natural Science Foundation of China [Grant Nos. 51779024, 51879022, 51979045, 51906029], Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) [No.311021013], Natural Science Foundation of Liaoning Province of China [2020MS130].