Brötz, Johannes ; Schänzle, Christian ; Pelz, Peter F. (2024)
Exergy-Based Efficiency Assessment of Fans vs. Isentropic Efficiency.
In: International Journal of Turbomachinery, Propulsion and Power, 2023, 8 (4)
doi: 10.26083/tuprints-00026556
Artikel, Zweitveröffentlichung, Verlagsversion
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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: | 2024 |
| Autor(en): | Brötz, Johannes ; Schänzle, Christian ; Pelz, Peter F. |
| Art des Eintrags: | Zweitveröffentlichung |
| Titel: | Exergy-Based Efficiency Assessment of Fans vs. Isentropic Efficiency |
| Sprache: | Englisch |
| Publikationsjahr: | 30 September 2024 |
| Ort: | Darmstadt |
| Publikationsdatum der Erstveröffentlichung: | 2023 |
| Ort der Erstveröffentlichung: | Basel |
| Verlag: | MDPI |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | International Journal of Turbomachinery, Propulsion and Power |
| Jahrgang/Volume einer Zeitschrift: | 8 |
| (Heft-)Nummer: | 4 |
| Kollation: | 9 Seiten |
| DOI: | 10.26083/tuprints-00026556 |
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/26556 |
| Zugehörige Links: | |
| Herkunft: | Zweitveröffentlichungsservice |
| 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. |
| Freie Schlagworte: | exergy, efficiency, fan, second law |
| Status: | Verlagsversion |
| URN: | urn:nbn:de:tuda-tuprints-265563 |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau |
| Fachbereich(e)/-gebiet(e): | 16 Fachbereich Maschinenbau 16 Fachbereich Maschinenbau > Institut für Fluidsystemtechnik (FST) (seit 01.10.2006) |
| Hinterlegungsdatum: | 30 Sep 2024 09:41 |
| Letzte Änderung: | 04 Okt 2024 07:15 |
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| Suche nach Titel in: | TUfind oder in Google |
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- Exergy-Based Efficiency Assessment of Fans vs. Isentropic Efficiency. (deposited 30 Sep 2024 09:41) [Gegenwärtig angezeigt]
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