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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

Theoretical investigation of the bubble growth and collapse process.(a) CFD simulation and experimental results for the bubble oscillation period τ and the maximum bubble expansion diameter D as a function of the inlet cross-sectional area A. Blue dots represent simulation results for the bubble oscillation period τ , while the blue line represents the best fit of the form τ ~ A−1/2. Red dots represent experimental results for the bubble oscillation period τ, while the magenta line represents the best fit of the form τ ~ A−1/2. Green dots represent simulation results for the maximum bubble expansion diameter D. The dashed green line is to guide the eye only. The following values are used: τ0 = 10 ms, D0 = 0.16 mm, A0 = 0.0154 mm2. (b) CFD simulation and experimental results for the maximum bubble expansion diameter D as a function of the gap H between the membrane and the electrode. Blue dots represent simulation results for the maximum bubble expansion diameter D. Red dots represent experimental results for the maximum bubble expansion diameter D, while the magenta line represents the best fit of the form D ~ H2. The following values are used: τ0 = 10 ms, H0 = 0.16 mm. (c) CFD simulation and experimental results for the bubble oscillation period τ as a function of the gap H between the membrane and the electrode. Blue dots represent simulation results for the bubble oscillation period τ , while the blue line represents the best fit of the form τ ~ H. Red dots represent experimental results for the bubble oscillation period τ , while the magenta line represents the best fit of the form τ ~ H4. The following values are used: H0 = D0 = 0.16 mm. (d) The dependence of the bubble oscillation period τ on the mercury and air inlet pressures, PHg and PAir respectively. The solid lines are to guide the eye only.
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f5: Theoretical investigation of the bubble growth and collapse process.(a) CFD simulation and experimental results for the bubble oscillation period τ and the maximum bubble expansion diameter D as a function of the inlet cross-sectional area A. Blue dots represent simulation results for the bubble oscillation period τ , while the blue line represents the best fit of the form τ ~ A−1/2. Red dots represent experimental results for the bubble oscillation period τ, while the magenta line represents the best fit of the form τ ~ A−1/2. Green dots represent simulation results for the maximum bubble expansion diameter D. The dashed green line is to guide the eye only. The following values are used: τ0 = 10 ms, D0 = 0.16 mm, A0 = 0.0154 mm2. (b) CFD simulation and experimental results for the maximum bubble expansion diameter D as a function of the gap H between the membrane and the electrode. Blue dots represent simulation results for the maximum bubble expansion diameter D. Red dots represent experimental results for the maximum bubble expansion diameter D, while the magenta line represents the best fit of the form D ~ H2. The following values are used: τ0 = 10 ms, H0 = 0.16 mm. (c) CFD simulation and experimental results for the bubble oscillation period τ as a function of the gap H between the membrane and the electrode. Blue dots represent simulation results for the bubble oscillation period τ , while the blue line represents the best fit of the form τ ~ H. Red dots represent experimental results for the bubble oscillation period τ , while the magenta line represents the best fit of the form τ ~ H4. The following values are used: H0 = D0 = 0.16 mm. (d) The dependence of the bubble oscillation period τ on the mercury and air inlet pressures, PHg and PAir respectively. The solid lines are to guide the eye only.

Mentions: The typical results obtained by CFD modeling for the time dependence of the footprint area of the bubble are shown in Fig. 4(e). The dependence of the bubble oscillation period and the maximum bubble expansion diameter on the size of the gap between the electrode and the membrane are shown in Fig. 5(c) and Fig. 5(b) respectively. The gap size exerts a profound influence on the bubble dynamics. As one can see from Fig. 5(b,c) the predicted bubble oscillation period appears to be a liner function of the gap size, while the predicted maximum bubble expansion diameter appear to be a quadratic function of the gap size.


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)

Theoretical investigation of the bubble growth and collapse process.(a) CFD simulation and experimental results for the bubble oscillation period τ and the maximum bubble expansion diameter D as a function of the inlet cross-sectional area A. Blue dots represent simulation results for the bubble oscillation period τ , while the blue line represents the best fit of the form τ ~ A−1/2. Red dots represent experimental results for the bubble oscillation period τ, while the magenta line represents the best fit of the form τ ~ A−1/2. Green dots represent simulation results for the maximum bubble expansion diameter D. The dashed green line is to guide the eye only. The following values are used: τ0 = 10 ms, D0 = 0.16 mm, A0 = 0.0154 mm2. (b) CFD simulation and experimental results for the maximum bubble expansion diameter D as a function of the gap H between the membrane and the electrode. Blue dots represent simulation results for the maximum bubble expansion diameter D. Red dots represent experimental results for the maximum bubble expansion diameter D, while the magenta line represents the best fit of the form D ~ H2. The following values are used: τ0 = 10 ms, H0 = 0.16 mm. (c) CFD simulation and experimental results for the bubble oscillation period τ as a function of the gap H between the membrane and the electrode. Blue dots represent simulation results for the bubble oscillation period τ , while the blue line represents the best fit of the form τ ~ H. Red dots represent experimental results for the bubble oscillation period τ , while the magenta line represents the best fit of the form τ ~ H4. The following values are used: H0 = D0 = 0.16 mm. (d) The dependence of the bubble oscillation period τ on the mercury and air inlet pressures, PHg and PAir respectively. The solid lines are to guide the eye only.
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f5: Theoretical investigation of the bubble growth and collapse process.(a) CFD simulation and experimental results for the bubble oscillation period τ and the maximum bubble expansion diameter D as a function of the inlet cross-sectional area A. Blue dots represent simulation results for the bubble oscillation period τ , while the blue line represents the best fit of the form τ ~ A−1/2. Red dots represent experimental results for the bubble oscillation period τ, while the magenta line represents the best fit of the form τ ~ A−1/2. Green dots represent simulation results for the maximum bubble expansion diameter D. The dashed green line is to guide the eye only. The following values are used: τ0 = 10 ms, D0 = 0.16 mm, A0 = 0.0154 mm2. (b) CFD simulation and experimental results for the maximum bubble expansion diameter D as a function of the gap H between the membrane and the electrode. Blue dots represent simulation results for the maximum bubble expansion diameter D. Red dots represent experimental results for the maximum bubble expansion diameter D, while the magenta line represents the best fit of the form D ~ H2. The following values are used: τ0 = 10 ms, H0 = 0.16 mm. (c) CFD simulation and experimental results for the bubble oscillation period τ as a function of the gap H between the membrane and the electrode. Blue dots represent simulation results for the bubble oscillation period τ , while the blue line represents the best fit of the form τ ~ H. Red dots represent experimental results for the bubble oscillation period τ , while the magenta line represents the best fit of the form τ ~ H4. The following values are used: H0 = D0 = 0.16 mm. (d) The dependence of the bubble oscillation period τ on the mercury and air inlet pressures, PHg and PAir respectively. The solid lines are to guide the eye only.
Mentions: The typical results obtained by CFD modeling for the time dependence of the footprint area of the bubble are shown in Fig. 4(e). The dependence of the bubble oscillation period and the maximum bubble expansion diameter on the size of the gap between the electrode and the membrane are shown in Fig. 5(c) and Fig. 5(b) respectively. The gap size exerts a profound influence on the bubble dynamics. As one can see from Fig. 5(b,c) the predicted bubble oscillation period appears to be a liner function of the gap size, while the predicted maximum bubble expansion diameter appear to be a quadratic function of the gap size.

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