-1-A Novel Pyroelectric Generator Utilising Naturally Driven Temperature 1 Fluctuations from Oscillating Heat Pipes (OHPs) for Waste Heat Recovery 2 and Thermal Energy Harvesting

, Abstract: Low temperature thermal to electrical e nergy converters have the potential to provide a route 9 for recovering waste energy. In this paper we propose a new configuration of a thermal harvester that us es 10 a naturally driven thermal oscillator free of mechanical m otion and operat es between a hot heat source 11 and a cold heat sink . The system exploits a heat induced liquid - vapour transition of a working fluid as a 12 primary driver for a pyroelectric generator . The two - phase instability of a fluid in a closed looped 13 capillary channel of a n oscillating heat pipe ( OHP ) creates pressure difference s which lead to local high 14 frequency temperature oscillation s i n the range of 0.1 – 5 [ K ] . Such temperature changes are suitable for 15 pyroelectric thermal to electrical energy conversion , where t he pyroelectric generator is attached to the 16 adiabatic wall of the OHP , thereby absorbing thermal energy from the passing fluid . This new 17 pyroelectric - oscillating heat pipe (POHP) a ssembly of a low temperature generator continuousl y operates 18 across a spatial heat source temperature of 55 ° C and a heat sink temperature of 25 ° C , and enabl es waste 19 heat recovery and the rmal energy harvesting f rom small temperature gradient s at low temperatures. Our 20 electrical measurements with l ead

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