a novel pyroelectric generator utilising thermal...
TRANSCRIPT
A novel pyroelectric generator utilising thermal
fluctuations from oscillating heat pipes (OHPs) for
waste heat recovery and thermal energy harvesting
Daniel Zabek*1, John Taylor1, Vincent Ayel2, Yves Betin2, Cyril Romestant2, and Chris Bowen1
1University of Bath, Calverton Down, BA2 7AY, (UK).2Pprime Institut CNRS – ENSMA – Universite de Poitiers, UPR 3346, (FR).
*e: [email protected], [email protected]
11th of May 2016
Energy Harvesting 2016, London (UK)
Thermal energy harvesting / waste heat recovery
70 WattTh
100 WattTh
500 WattTh
Definition: A heat exchanger is a piece of equipment built for efficient
heat transfer from one medium to another.
40 WattTh
• Extend battery life.
• Improve energy efficiency.
• Reduce thermal pollution.
• Reduce fan noise.
Heat
Source
Heat
Sink
[1] Khandekar and Groll (2004) An insight into thermo-hydrodynamic coupling in closed loop pulsating heat pipes.
CondenserEvaporator
Pipes/channels
“Two phase instability due to the surface tension,
the capillary effect and a temperature differences”
Oscillating motion
Liquid slug
Vapour bubble
Real time (x 1.0)
Adiabatic section
Oscillating Heat pipe (OHP)
Rapid temperature fluctuation at the channel wall
Chaotic mode with random
temperature oscillation
Under constant thermal boundary condition the OHP
exhibits rapid- and high-temperature oscillation.
Steady state mode with harmonic
temperature oscillation
Q
Temperature
P
Pyroelectric effect
A
𝐼 = 𝑝. 𝐴∆𝑇
∆𝑡• Flexible, light and cheap materials.
• Scalable in size, temperature range and supply voltage.
V=0 ΔVPd
Δ𝑉 =𝑝
ε𝑑. Δ𝑇
_ _ _ _ _ _
+ + + + + +
_ _ _ _ _ _
+ + + + + +
Combined Pyroelectric (P) - Oscillating Heat pipe (OHP)
Change in thermo-fluid properties between liquid and vapour phase.
[2] Pat.: GB1603373 (2016) Apparatus and Method for Generating Electrical Energy.
Pyroelectric - Oscillating Heat Pipe (POHP) generator
[2] Pat.: GB1603373 (2016) Apparatus and Method for Generating Electrical Energy.
Proof of concept.
• No mechanical motion.
• High performance
cooling for heat
concentrated areas.
• Flexible size & shape.
• Solid state design.
• Infinite lifetime.
PZTSilver
Pyroelectric element:
PMN-PT currentPZT current
Steady state POHP I (current)
Due to better pyroelectric and heat transfer coefficients, PMN-PT
outperforms standard PZT pyroelectric material with POHP.
[3] Zabek et al. (under review) A Novel Pyroelectric Generator Utilising Naturally Driven Temperature Fluctuations from OHPs…
PMN-PT currentPMN-PT voltage
Steady state POHP II (voltage & current)
Steady state operation of POHP induces harmonic
pyroelectric voltage and current at 0.45 Hz.
[3] Zabek et al. (under review) A Novel Pyroelectric Generator Utilising Naturally Driven Temperature Fluctuations from OHPs…
PMN-PT current
Chaotic operation of POHP
Chaotic operation of POHP induces
random pyroelectric current.
• Large changes in temperature.
• Fast changes in temperature.
• High pyroelectric current.
[3] Zabek et al. (under review) A Novel Pyroelectric Generator Utilising Naturally Driven Temperature Fluctuations from OHPs…
POHP thermal energy harvesting (PMN-PT)
Capacitor
Pyro
Rectified chaotic current Rectified steady state current
More energy recovered in chaotic operation than in steady state operation.
[3] Zabek et al. (under review) A Novel Pyroelectric Generator Utilising Naturally Driven Temperature Fluctuations from OHPs…
Conclusions & future work
• First pyroelectric generator driven by natural and self induced temperature oscillator.
• No mechanical motion.
• Novel thermal generator utilising low temperature heat.
• Scalable in size, temperature range and supply voltage.
• Standalone low or ultra-low electric power supply.
• Device η = ? (input is zero since heat is free).
• Eg. could improve battery life by 1 - 4 %.
The research leading to these results has received funding from the European Research Council
under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant
Agreement no. 320963 on Novel Energy Materials, Engineering Science and Integrated Systems.
Acknowledgements