Title: Extension of energy-utilisation diagram to power availability for exergy loss analysis

Authors: Winit Bouapetch; Pongsiri Tungwungwiwat; Thongchai Srinophakun

Addresses: Center of Excellence on Petrochemical and Materials Technology, Center for Advanced Studies in Industrial Technology, Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10903, Thailand ' Department of Chemical Engineering, Faculty of Engineering, Chemical Engineering Practice School, King Mongkut's University of Technology, Thonburi, Bangkok 10140, Thailand ' Center of Excellence on Petrochemical and Materials Technology, Center for Advanced Studies in Industrial Technology, Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10903, Thailand

Abstract: Energy-Utilisation Diagram (EUD) has been used to identify exergy loss in general process units, whereas Power Availability Diagram (PAD) provides the difference between exergy changes of two pressure exchangers. Two modifications of the original PAD are proposed for better exergy loss visualisation. Firstly, the energy donor curve is shifted to the location of energy acceptor. Secondly, arrows indicating the exergy change direction are inserted in the diagram. This research leads to Modified Power Availability Diagram (MPAD) that can identify the exergy loss. From the applied Rankine cycle, MPAD was changed in two forms as MCPAD (Modified Cycle Power Availability Diagram) and MSPAD (Modified Subsystem Power Availability Diagram). The results showed that MPAD can presents the exergy profile of the working fluid and MSPAD can reduce the complexity of EUD and show the exergy loss of each unit in the cycle. The advantages of MCPAD can present the graphical exergy distribution.

Keywords: energy utilisation diagram; power availability diagram; exergy analysis; Rankine cycle; exergy loss analysis; graphical exergy distribution.

DOI: 10.1504/IJEX.2013.054116

International Journal of Exergy, 2013 Vol.12 No.3, pp.323 - 343

Received: 21 Dec 2011
Accepted: 24 Jun 2012
Published online: 23 May 2013 *

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