Optimal Heat Source Temperature for thermodynamic optimization of sub-critical Organic Rankine Cycles

Wei Liu, Dominik Meinel, Moritz Gleinser, Christoph Wieland and Hartmut Spliethoff

Energy, 2015, vol. 88, issue C, 897-906

Abstract: Based on a sub-critical ORC (Organic Rankine Cycle) process, this study introduces the term OHST (Optimal Heat Source Temperature) with consideration of a suitable thermal match between heat source and working fluid. A theoretical formula is developed for predicting the OHST, which shows that OHST only depends on evaporation pressure and pinch point in the preheater and evaporator. A comparative study between the predicted OHSTs and those obtained from cycle simulations is performed, showing that the proposed formula is reliable, provided that HTF (Heat Transfer Fluid) is homogeneous and has good consistency in terms of heat capacity for different temperatures. To demonstrate the application of the proposed OHST-theory for thermodynamic optimization of ORC systems, a case study is presented based on a simple ORC coupled with thermal water at 140 °C. Consequently, using R227ea leads to the highest system efficiency of 10.38%, due to a better thermal match in the preheater and evaporator. In order to increase the exploitation of the thermal potential from the heat source, a dual-fluid-ORC is proposed, where R245fa and R227ea are considered for the high and low temperature ORC processes, respectively. Finally, this combination leads to the highest system efficiency of 11.07%.

Keywords: Optimal Heat Source Temperature; Organic Rankine Cycle; Heat Transfer Fluid; Working fluid; Pinch point; Exergetic efficiency (search for similar items in EconPapers)
Date: 2015
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (8)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544215009354
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:88:y:2015:i:c:p:897-906

DOI: 10.1016/j.energy.2015.07.040

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 ().