Entropy generation versus transition time of heat exchanger during transient processes

Kezhen Zhang, Ming Liu, Yongliang Zhao, Chaoyang Wang and Junjie Yan

Energy, 2020, vol. 200, issue C

Abstract: The flexibility of thermal power plants plays a critical role to accommodate high penetration of fluctuant renewable energy. Heat exchanger is the key device restricting the flexibility and energy efficiency of thermal power plants owing to its large thermal inertia. Therefore, evaluation of the additional entropy generation and transition time for the heat exchanger during transient processes is important, which are quantitative measures of the efficiency and flexibility. Consequently, dynamic models of a heat exchanger are developed. The dynamic behaviors of the heat exchanger are analyzed using numerical simulation and entropy generation analyses. The relationship between additional entropy generation and transition time is determined. Results show that: when flow rate decreases and temperature increases, this relationship is synergetic for hot fluid, metal wall and heat exchanger. The opposite correlation occurs when flow rate increases and temperature decreases. However, the cold fluid has the contrary tendency. The augmentation in heat transfer resistance reduces the additional entropy generation and transition time, whereas the effect of increasing the range of the boundary disturbances, such as temperature and flow rate, is on the contrary. For a heat exchanger, the additional entropy generation versus the transition time can be described by an exponential function.

Keywords: Heat exchanger; Transient process; Entropy generation; Transition time; Flexibility (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544220305971
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:200:y:2020:i:c:s0360544220305971

DOI: 10.1016/j.energy.2020.117490

Access Statistics for this article

Energy is currently edited by Henrik Lund and Mark J. Kaiser

More articles in Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().