Details
| Original language | English |
|---|---|
| Pages (from-to) | 233-241 |
| Number of pages | 9 |
| Journal | Energy Harvesting and Systems |
| Volume | 1 |
| Issue number | 3 |
| Early online date | 4 Sept 2014 |
| Publication status | Published - 1 Dec 2014 |
Abstract
Two concepts of scaled micro-flywheel-energy-storage systems (FESSs): a flat disk-shaped and a thin ring-shaped (outer diameter equal to height) flywheel rotors were examined in this study, focusing on material selection, energy content, losses due to air friction and motor loss. For the disk-shape micro-FESS, isotropic materials like titanium, aluminum, steel and wolfram are shown to be suitable as a flywheel rotor. Wound fiber reinforced composite plastics (T1000-, T300-carbon fibers and carbon nanotubes "CNTs") were investigated for the flywheel in a ring shape. It was shown that isotropic materials reach the highest energy densities in the shape of a Laval disk with a rim. A micro-FESS with wolfram flywheel would reach the highest half-time-periods due to its high density, and thus, it is the favored material to design a flat disk-shaped micro-FESS with low standby-losses. Fiber reinforced plastic flywheels in ring shape reach the highest energy densities, from 150 W h/kg (T300) to 2,600 W h/kg (CNT), but display higher standby-losses as well. A scaling of the rotors was done within this study and showed that air friction is influenced by the shape of the examined flywheel rotors and the material. A linear correlation of down scaling and air friction losses was shown. As a motor/generator type, an ironless air coil Halbach array motor was suggested. Motor losses due to eddy currents in the stator coil were estimated. Losses correlated in square with downscaling. FESSs with wolfram and CNT showed the lowest standby-losses due to eddy currents.
Keywords
- energy harvester, flywheel, micro energy storage, micro-FESS
ASJC Scopus subject areas
- Energy(all)
- Renewable Energy, Sustainability and the Environment
- Energy(all)
- Energy Engineering and Power Technology
- Engineering(all)
- Electrical and Electronic Engineering
- Chemistry(all)
- Electrochemistry
Sustainable Development Goals
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In: Energy Harvesting and Systems, Vol. 1, No. 3, 01.12.2014, p. 233-241.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Feasibility Study for Small Scaling Flywheel-Energy-Storage Systems in Energy Harvesting Systems
AU - Ertz, Gabriel
AU - Twiefel, Jens
AU - Krack, Malte
PY - 2014/12/1
Y1 - 2014/12/1
N2 - Two concepts of scaled micro-flywheel-energy-storage systems (FESSs): a flat disk-shaped and a thin ring-shaped (outer diameter equal to height) flywheel rotors were examined in this study, focusing on material selection, energy content, losses due to air friction and motor loss. For the disk-shape micro-FESS, isotropic materials like titanium, aluminum, steel and wolfram are shown to be suitable as a flywheel rotor. Wound fiber reinforced composite plastics (T1000-, T300-carbon fibers and carbon nanotubes "CNTs") were investigated for the flywheel in a ring shape. It was shown that isotropic materials reach the highest energy densities in the shape of a Laval disk with a rim. A micro-FESS with wolfram flywheel would reach the highest half-time-periods due to its high density, and thus, it is the favored material to design a flat disk-shaped micro-FESS with low standby-losses. Fiber reinforced plastic flywheels in ring shape reach the highest energy densities, from 150 W h/kg (T300) to 2,600 W h/kg (CNT), but display higher standby-losses as well. A scaling of the rotors was done within this study and showed that air friction is influenced by the shape of the examined flywheel rotors and the material. A linear correlation of down scaling and air friction losses was shown. As a motor/generator type, an ironless air coil Halbach array motor was suggested. Motor losses due to eddy currents in the stator coil were estimated. Losses correlated in square with downscaling. FESSs with wolfram and CNT showed the lowest standby-losses due to eddy currents.
AB - Two concepts of scaled micro-flywheel-energy-storage systems (FESSs): a flat disk-shaped and a thin ring-shaped (outer diameter equal to height) flywheel rotors were examined in this study, focusing on material selection, energy content, losses due to air friction and motor loss. For the disk-shape micro-FESS, isotropic materials like titanium, aluminum, steel and wolfram are shown to be suitable as a flywheel rotor. Wound fiber reinforced composite plastics (T1000-, T300-carbon fibers and carbon nanotubes "CNTs") were investigated for the flywheel in a ring shape. It was shown that isotropic materials reach the highest energy densities in the shape of a Laval disk with a rim. A micro-FESS with wolfram flywheel would reach the highest half-time-periods due to its high density, and thus, it is the favored material to design a flat disk-shaped micro-FESS with low standby-losses. Fiber reinforced plastic flywheels in ring shape reach the highest energy densities, from 150 W h/kg (T300) to 2,600 W h/kg (CNT), but display higher standby-losses as well. A scaling of the rotors was done within this study and showed that air friction is influenced by the shape of the examined flywheel rotors and the material. A linear correlation of down scaling and air friction losses was shown. As a motor/generator type, an ironless air coil Halbach array motor was suggested. Motor losses due to eddy currents in the stator coil were estimated. Losses correlated in square with downscaling. FESSs with wolfram and CNT showed the lowest standby-losses due to eddy currents.
KW - energy harvester
KW - flywheel
KW - micro energy storage
KW - micro-FESS
UR - http://www.scopus.com/inward/record.url?scp=85118780818&partnerID=8YFLogxK
U2 - 10.1515/ehs-2013-0010
DO - 10.1515/ehs-2013-0010
M3 - Article
AN - SCOPUS:85118780818
VL - 1
SP - 233
EP - 241
JO - Energy Harvesting and Systems
JF - Energy Harvesting and Systems
SN - 2329-8774
IS - 3
ER -