Abstract
Low temperature thermal to electrical energy converters have the potential to provide a route for recovering waste energy. In this paper, we propose a new configuration of a thermal harvester that uses a naturally driven thermal oscillator free of mechanical motion and operates between a hot heat source and a cold heat sink. The system exploits a heat induced liquid-vapour transition of a working fluid as a primary driver for a pyroelectric generator. The two-phase instability of a fluid in a closed looped capillary channel of an oscillating heat pipe (OHP) creates pressure differences which lead to local high frequency temperature oscillations in the range of 0.1–5 K. Such temperature changes are suitable for pyroelectric thermal to electrical energy conversion, where the pyroelectric generator is attached to the adiabatic wall of the OHP, thereby absorbing thermal energy from the passing fluid. This new pyroelectric-oscillating heat pipe (POHP) assembly of a low temperature generator continu- ously operates across a spatial heat source temperature of 55 C and a heat sink temperature of 25 C, and enables waste heat recovery and thermal energy harvesting from small temperature gradients at low temperatures. Our electrical measurements with lead zirconate titanate (PZT) show an open circuit voltage of 0.4 V (AC) and with lead magnesium niobate–lead titanate (PMN-PT) an open circuit volt- age of 0.8 V (AC) at a frequency of 0.45 Hz, with an energy density of 95 pJ cm 3 for PMN-PT. Our novel POHP device therefore has the capability to convert small quantities of thermal energy into more desirable electricity in the nW to mW range and provides an alternative to currently used batteries or centralised energy generation.
Original language | English |
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Article number | 024505 (2016) |
Pages (from-to) | 1-8 |
Number of pages | 8 |
Journal | Journal of Applied Physics |
Volume | 120 |
Issue number | 2 |
Early online date | 13 Jul 2016 |
DOIs | |
Publication status | Published - 14 Jul 2016 |
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Chris Bowen
- Department of Mechanical Engineering - Professor
- Faculty of Engineering and Design - Associate Dean (Research)
- Centre for Sustainable Chemical Technologies (CSCT)
- Centre for Nanoscience and Nanotechnology
- Institute for Mathematical Innovation (IMI)
- Institute of Sustainability and Climate Change
- Centre for Integrated Materials, Processes & Structures (IMPS)
- IAAPS: Propulsion and Mobility
Person: Research & Teaching, Core staff, Affiliate staff
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John Taylor
- Department of Electronic & Electrical Engineering - Professor
- Electronics Materials, Circuits & Systems Research Unit (EMaCS)
Person: Research & Teaching