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Exergy Based Efficiency Assessment for Fans in Comparison to Common Used Efficiency Definitions

Brötz, Johannes ; Schänzle, Christian ; Pelz, Peter F. (2022)
Exergy Based Efficiency Assessment for Fans in Comparison to Common Used Efficiency Definitions.
FAN 2022 – International Conference on Fan Noise, Aerodynamics, Applications and Systems. Senlis, Frankreich (27.06.-29.06.2022)
doi: 10.26083/tuprints-00021722
Conference or Workshop Item, Primary publication, Publisher's Version

Abstract

The efficiency definition allows the comparison of 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 grounds 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, too. On this basis, a comparison between isentropic and exergetic efficiency is given. A high-pressure radial fan is used as an example and the differences are discussed. Therefore, measurements at a non-adiabatic fan is evaluated and the role of the heat flux to the environment is discussed. For a standard such as ISO 5801 "Fans - Performance testing using standardized airways", 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.

Item Type: Conference or Workshop Item
Erschienen: 2022
Creators: Brötz, Johannes ; Schänzle, Christian ; Pelz, Peter F.
Type of entry: Primary publication
Title: Exergy Based Efficiency Assessment for Fans in Comparison to Common Used Efficiency Definitions
Language: English
Date: 2022
Place of Publication: Darmstadt
Collation: 11 Seiten
Event Title: FAN 2022 – International Conference on Fan Noise, Aerodynamics, Applications and Systems
Event Location: Senlis, Frankreich
Event Dates: 27.06.-29.06.2022
DOI: 10.26083/tuprints-00021722
URL / URN: https://tuprints.ulb.tu-darmstadt.de/21722
Abstract:

The efficiency definition allows the comparison of 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 grounds 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, too. On this basis, a comparison between isentropic and exergetic efficiency is given. A high-pressure radial fan is used as an example and the differences are discussed. Therefore, measurements at a non-adiabatic fan is evaluated and the role of the heat flux to the environment is discussed. For a standard such as ISO 5801 "Fans - Performance testing using standardized airways", 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.

Status: Publisher's Version
URN: urn:nbn:de:tuda-tuprints-217229
Classification DDC: 600 Technology, medicine, applied sciences > 620 Engineering and machine engineering
Divisions: 16 Department of Mechanical Engineering
16 Department of Mechanical Engineering > Institute for Fluid Systems (FST) (since 01.10.2006)
Date Deposited: 02 Aug 2022 11:10
Last Modified: 03 Aug 2022 05:50
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