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Bubbler: A Novel Ultra-High Power Density Energy Harvesting Method Based on Reverse Electrowetting.

Hsu TH, Manakasettharn S, Taylor JA, Krupenkin T - Sci Rep (2015)

Bottom Line: We have proposed and successfully demonstrated a novel approach to direct conversion of mechanical energy into electrical energy using microfluidics.Fast bubble dynamics, used in conjunction with REWOD, provides a possibility to increase the generated power density by over an order of magnitude, as compared to the REWOD alone.This energy conversion approach is particularly well suited for energy harvesting applications and can enable effective coupling to a broad array of mechanical systems including such ubiquitous but difficult to utilize low-frequency energy sources as human and machine motion.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University of Wisconsin-Madison, 1513 UniversityAvenue, Mechanical Engineering Building Room 2238, Madison, WI, 53706, USA.

ABSTRACT
We have proposed and successfully demonstrated a novel approach to direct conversion of mechanical energy into electrical energy using microfluidics. The method combines previously demonstrated reverse electrowetting on dielectric (REWOD) phenomenon with the fast self-oscillating process of bubble growth and collapse. Fast bubble dynamics, used in conjunction with REWOD, provides a possibility to increase the generated power density by over an order of magnitude, as compared to the REWOD alone. This energy conversion approach is particularly well suited for energy harvesting applications and can enable effective coupling to a broad array of mechanical systems including such ubiquitous but difficult to utilize low-frequency energy sources as human and machine motion. The method can be scaled from a single micro cell with 10(-6) W output to power cell arrays with a total power output in excess of 10 W. This makes the fabrication of small light-weight energy harvesting devices capable of producing a wide range of power outputs feasible.

No MeSH data available.


Related in: MedlinePlus

The bubbler concept.(a) Bubbler conceptual design: (1) indicates REWOD chip, (2) membrane, (3) top plate, (4) an array of bubbles, and (5) an array of electrodes. (b) Schematics of a simplified single-electrode device used in the experiment: (1) represents REWOD chip, (2) membrane, (3) top plate, (4) bubble, (5) metal electrode, (6) dielectric coating, and (7) conductive liquid. (c) Equivalent electrical circuit for a single-electrode device.
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f2: The bubbler concept.(a) Bubbler conceptual design: (1) indicates REWOD chip, (2) membrane, (3) top plate, (4) an array of bubbles, and (5) an array of electrodes. (b) Schematics of a simplified single-electrode device used in the experiment: (1) represents REWOD chip, (2) membrane, (3) top plate, (4) bubble, (5) metal electrode, (6) dielectric coating, and (7) conductive liquid. (c) Equivalent electrical circuit for a single-electrode device.

Mentions: The bubbler conceptual design is very simple and is shown in Fig. 2. The core of the bubbler contains no moving mechanical parts and consists of only three major elements: (i) a REWOD chip with an array of dielectric-coated circular electrodes, each electrode having a hole in the center, (ii) a thin membrane separated from the REWOD chip by a small gap, and (iii) a top plate, which serves to support the membrane and allows the dielectric fluid to escape. The gap between the REWOD chip and the membrane is filled with the conductive liquid, which does not wet the membrane and thus cannot penetrate it, as shown in Fig. 2(b). A pressurized dielectric fluid (e.g. air, inert gas, or a dielectric liquid) is supplied through the holes in the chip, causing dielectric bubbles to grow on top of each circular electrode. The growing bubbles displace the conductive liquid and thus reduce the area of overlap between the conductive liquid and the electrodes, inducing electrical current in the circuit. Each bubble continues to grow until it becomes large enough to touch the membrane. At this point the dielectric fluid starts to escape through the membrane, causing a rapid bubble collapse. The frequency, with which the bubble growth and collapse process repeats itself, is controlled by the size of the gap between the membrane and the electrode, by the viscosities of the fluids, and by the pressures applied to the dielectric fluid and the conductive liquid. A video with the animation of the bubbler operation is provided in the Supplementary Materials (see Supplementary Video 1). A detailed description of the bubbler device fabrication is given in the Methods section.


Bubbler: A Novel Ultra-High Power Density Energy Harvesting Method Based on Reverse Electrowetting.

Hsu TH, Manakasettharn S, Taylor JA, Krupenkin T - Sci Rep (2015)

The bubbler concept.(a) Bubbler conceptual design: (1) indicates REWOD chip, (2) membrane, (3) top plate, (4) an array of bubbles, and (5) an array of electrodes. (b) Schematics of a simplified single-electrode device used in the experiment: (1) represents REWOD chip, (2) membrane, (3) top plate, (4) bubble, (5) metal electrode, (6) dielectric coating, and (7) conductive liquid. (c) Equivalent electrical circuit for a single-electrode device.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4645099&req=5

f2: The bubbler concept.(a) Bubbler conceptual design: (1) indicates REWOD chip, (2) membrane, (3) top plate, (4) an array of bubbles, and (5) an array of electrodes. (b) Schematics of a simplified single-electrode device used in the experiment: (1) represents REWOD chip, (2) membrane, (3) top plate, (4) bubble, (5) metal electrode, (6) dielectric coating, and (7) conductive liquid. (c) Equivalent electrical circuit for a single-electrode device.
Mentions: The bubbler conceptual design is very simple and is shown in Fig. 2. The core of the bubbler contains no moving mechanical parts and consists of only three major elements: (i) a REWOD chip with an array of dielectric-coated circular electrodes, each electrode having a hole in the center, (ii) a thin membrane separated from the REWOD chip by a small gap, and (iii) a top plate, which serves to support the membrane and allows the dielectric fluid to escape. The gap between the REWOD chip and the membrane is filled with the conductive liquid, which does not wet the membrane and thus cannot penetrate it, as shown in Fig. 2(b). A pressurized dielectric fluid (e.g. air, inert gas, or a dielectric liquid) is supplied through the holes in the chip, causing dielectric bubbles to grow on top of each circular electrode. The growing bubbles displace the conductive liquid and thus reduce the area of overlap between the conductive liquid and the electrodes, inducing electrical current in the circuit. Each bubble continues to grow until it becomes large enough to touch the membrane. At this point the dielectric fluid starts to escape through the membrane, causing a rapid bubble collapse. The frequency, with which the bubble growth and collapse process repeats itself, is controlled by the size of the gap between the membrane and the electrode, by the viscosities of the fluids, and by the pressures applied to the dielectric fluid and the conductive liquid. A video with the animation of the bubbler operation is provided in the Supplementary Materials (see Supplementary Video 1). A detailed description of the bubbler device fabrication is given in the Methods section.

Bottom Line: We have proposed and successfully demonstrated a novel approach to direct conversion of mechanical energy into electrical energy using microfluidics.Fast bubble dynamics, used in conjunction with REWOD, provides a possibility to increase the generated power density by over an order of magnitude, as compared to the REWOD alone.This energy conversion approach is particularly well suited for energy harvesting applications and can enable effective coupling to a broad array of mechanical systems including such ubiquitous but difficult to utilize low-frequency energy sources as human and machine motion.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University of Wisconsin-Madison, 1513 UniversityAvenue, Mechanical Engineering Building Room 2238, Madison, WI, 53706, USA.

ABSTRACT
We have proposed and successfully demonstrated a novel approach to direct conversion of mechanical energy into electrical energy using microfluidics. The method combines previously demonstrated reverse electrowetting on dielectric (REWOD) phenomenon with the fast self-oscillating process of bubble growth and collapse. Fast bubble dynamics, used in conjunction with REWOD, provides a possibility to increase the generated power density by over an order of magnitude, as compared to the REWOD alone. This energy conversion approach is particularly well suited for energy harvesting applications and can enable effective coupling to a broad array of mechanical systems including such ubiquitous but difficult to utilize low-frequency energy sources as human and machine motion. The method can be scaled from a single micro cell with 10(-6) W output to power cell arrays with a total power output in excess of 10 W. This makes the fabrication of small light-weight energy harvesting devices capable of producing a wide range of power outputs feasible.

No MeSH data available.


Related in: MedlinePlus