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Exergy-Based Efficiency Assessment of Fans vs. Isentropic Efficiency

Brötz, Johannes ; Schänzle, Christian ; Pelz, Peter F. (2023)
Exergy-Based Efficiency Assessment of Fans vs. Isentropic Efficiency.
In: International Journal of Turbomachinery Propulsion and Power, 8 (1)
doi: 10.3390/ijtpp8010004
Artikel, Bibliographie

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Kurzbeschreibung (Abstract)

The efficiency definition allows us to compare two machines with each other. In general, the efficiency is defined as the ratio of usable power to the required power. This raises the question: what is the usable power? Most engineers discuss efficiency on the basis of the energy balance, i.e., the first law of thermodynamics. In this paper, we derive the exegetic efficiency taking the second law of thermodynamics into account. Exergy analysis takes into account work and heat and is able to model reality very accurately. On this basis, a comparison between the isentropic and exergetic efficiencies is given. A high-pressure radial fan is used as an example, and the differences are discussed. Therefore, measurements of a non-adiabatic fan are evaluated, and the role of the heat flux in the environment is discussed. The investigations show that a relevant difference between the isentropic and exergetic efficiencies becomes apparent in the partial-load range with high-pressure build-up. The thermal energy contained in the flow belongs proportionally to the exergy, i.e., the working capacity of the gas relative to its environment. For a standard such as ISO 5801 “Fans—Performance testing using standardized airways”, the efficiency must not only be physically correct, it must also be simple and practical. Against this background, the outlook of this paper discusses when and which efficiency definition is appropriate and best suited for a standard.

Typ des Eintrags: Artikel
Erschienen: 2023
Autor(en): Brötz, Johannes ; Schänzle, Christian ; Pelz, Peter F.
Art des Eintrags: Bibliographie
Titel: Exergy-Based Efficiency Assessment of Fans vs. Isentropic Efficiency
Sprache: Englisch
Publikationsjahr: 6 Februar 2023
Ort: Basel
Verlag: MDPI
Titel der Zeitschrift, Zeitung oder Schriftenreihe: International Journal of Turbomachinery Propulsion and Power
Jahrgang/Volume einer Zeitschrift: 8
(Heft-)Nummer: 1
Kollation: 9 Seiten
DOI: 10.3390/ijtpp8010004
URL / URN: https://www.mdpi.com/2504-186X/8/1/4
Zugehörige Links:
Kurzbeschreibung (Abstract):

The efficiency definition allows us to compare two machines with each other. In general, the efficiency is defined as the ratio of usable power to the required power. This raises the question: what is the usable power? Most engineers discuss efficiency on the basis of the energy balance, i.e., the first law of thermodynamics. In this paper, we derive the exegetic efficiency taking the second law of thermodynamics into account. Exergy analysis takes into account work and heat and is able to model reality very accurately. On this basis, a comparison between the isentropic and exergetic efficiencies is given. A high-pressure radial fan is used as an example, and the differences are discussed. Therefore, measurements of a non-adiabatic fan are evaluated, and the role of the heat flux in the environment is discussed. The investigations show that a relevant difference between the isentropic and exergetic efficiencies becomes apparent in the partial-load range with high-pressure build-up. The thermal energy contained in the flow belongs proportionally to the exergy, i.e., the working capacity of the gas relative to its environment. For a standard such as ISO 5801 “Fans—Performance testing using standardized airways”, the efficiency must not only be physically correct, it must also be simple and practical. Against this background, the outlook of this paper discusses when and which efficiency definition is appropriate and best suited for a standard.

Zusätzliche Informationen:

Artikel-ID: 4 // Special Issue Fan Noise, Aerodynamics, Applications and Systems

Fachbereich(e)/-gebiet(e): 16 Fachbereich Maschinenbau
16 Fachbereich Maschinenbau > Institut für Fluidsystemtechnik (FST) (seit 01.10.2006)
16 Fachbereich Maschinenbau > Institut für Fluidsystemtechnik (FST) (seit 01.10.2006) > Nachhaltige Kraft- und Arbeitssysteme
Hinterlegungsdatum: 08 Feb 2023 06:55
Letzte Änderung: 04 Okt 2024 07:15
PPN: 504455788
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