Charging Capacitors From Thermal Fluctuations Using Diodes
Rocky Mudbutt writes:
Collecting charge from a ribbon of single layer graphene, with a pair of diodes at the nanometer scale is a novel approach to converting heat to electricity.
Scitechdaily.com article on Non Linear power capture
From a new study published in the journal Physical Review E titled Charging capacitors from thermal fluctuations using diodes by P. M. Thibado, J. C. Neu, Pradeep Kumar, Surendra Singh and L. L. Bonilla, 16 August 2023, Physical Review
We theoretically consider a graphene ripple as a Brownian particle coupled to an energy storage circuit. When circuit and particle are at the same temperature, the second law forbids harvesting energy from the thermal motion of the Brownian particle, even if the circuit contains a rectifying diode. However, when the circuit contains a junction followed by two diodes wired in opposition, the approach to equilibrium may become ultraslow. Detailed balance is temporarily broken as current flows between the two diodes and charges storage capacitors. The energy harvested by each capacitor comes from the thermal bath of the diodes while the system obeys the first and second laws of thermodynamics.
[...] The scientists discovered that when the storage capacitors have an initial charge of zero, the circuit draws power from the thermal environment to charge them. The team then demonstrated that the system satisfies both the first and second laws of thermodynamics throughout the charging process. They also found that larger storage capacitors yield more stored charge and that a smaller graphene capacitance provides both a higher initial rate of charging and a longer time to discharge. These characteristics are important because they allow time to disconnect the storage capacitors from the energy harvesting circuit before the net charge is lost.
Journal Reference:
P. M. Thibado, J. C. Neu, Pradeep Kumar, Surendra Singh, and L. L. Bonilla, Charging capacitors from thermal fluctuations using diodes, Phys. Rev. E 108, 024130 - Published 16 August 2023. DOI: https://doi.org/10.1103/PhysRevE.108.024130
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