a novel pyroelectric generator utilising thermal...

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: D.Zabek@bath.ac.uk, Zabek@hotmail.de

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