Thermomagnetic hydrodynamic energy harvester

Matrix context

D = disequilibrium row · C = coupling family column. A cell reads the state of the atlas for that pair.

D.01 × C.06 · Temperature gradient × Thermomagneticfamily: ThermomagneticD.01 × C.14 · Temperature gradient × Electromagnetic inductionfamily: Electromagnetic induction

Measured or reported performance

1. extracted electrical power per kelvinup to 10.4 μW/Klaboratory2020
   toroidal closed loop, commercial ferrofluid packets in a water carrier, Peltier-controlled gradient, permanent magnets, poloidal or mixed poloidal/toroidal induction windings
   refs [3]

Typed bounds on this route

Every limit the atlas holds for this route, as constraint records: reached through bounded_by claims on the route's own entities. Hard bounds (an upper bound or a formula) decide the thermodynamic-bound check above; benchmarks, constitutive relations and resource limits are listed and never decisive. No prose limit exists anywhere (pass 42).

• Carnot limit · formula-bound · hard, applies to this route
  η ≤ 1 − T_c/T_h for any heat engine between reservoirs at T_h and T_c

Steps

1. 01
   Temperature gradient —drives→ Thermomagnetic convectionestablishedclaim record

   thermal → kinetic · loss to thermal

   • a ferrofluid whose magnetisation decreases with temperature, in a non-uniform magnetic field aligned with the temperature gradient

   liquid · magnetic field required · temperature gradient required

   refs [1] [2]
2. 02
   Thermomagnetic convection —couples to→ Electromagnetic inductiondemonstratedclaim record

   kinetic → electrical · loss to thermal

   • magnetised ferrofluid advects through a closed loop wound with induction coils, so the flux linked by each coil changes as magnetised packets pass
   • a permanent-magnet bias field keeps the fluid magnetised where it moves past the coils

   liquid · magnetic field required · temperature gradient required

   One lab-scale prototype (Chiolerio et al. 2020): a toroidal loop with poloidal or mixed poloidal/toroidal windings, water carrier with ferrofluid packets, up to 10.4 μW per kelvin. One paper is demonstrated, not established.

   refs [3]
3. 03
   Electromagnetic induction —produces→ Charge carriersestablishedclaim record

   electrical → electrical · loss to thermal

   refs [4] [5]
4. 04
   Charge carriers —converts into→ Electrical workestablishedclaim record

   electrical → electrical · loss to thermal

   • carriers driven through an external load at the potential difference the source maintains

   refs [6]

Evidence for the complete composition · 1

1. [3]
   A. Chiolerio et al.. Waste heat to power conversion by means of thermomagnetic hydrodynamic energy harvester (2020)

   Applied Energy 277, 115591 · doi:10.1016/j.apenergy.2020.115591 · record

Evidence for the constituent relations · 6

1. [1]
   R. E. Rosensweig. Ferrohydrodynamics (1985)

   Cambridge University Press · book, no DOI · record
2. [2]
   S. A. Suslov. Peculiarities of Convective Heat and Mass Transfer in Magnetic Nanofluids (2023)

   ASME Journal of Heat and Mass Transfer 145(3), 030801 (online December 2022) · doi:10.1115/1.4055343 · crossref ✓ 2026-09-20 · record
3. [3]
   A. Chiolerio et al.. Waste heat to power conversion by means of thermomagnetic hydrodynamic energy harvester (2020)

   Applied Energy 277, 115591 · doi:10.1016/j.apenergy.2020.115591 · record
4. [4]
   M. Faraday. Experimental researches in electricity (1832)

   Philosophical Transactions of the Royal Society 122, 125–162 · doi:10.1098/rstl.1832.0006 · crossref ✓ 2026-09-19 · record
5. [5]
   L. D. Landau, E. M. Lifshitz, L. P. Pitaevskii. Electrodynamics of Continuous Media (Course of Theoretical Physics, Vol. 8, 2nd ed.) (1984)

   Pergamon · book, no DOI · record
6. [6]
   N. W. Ashcroft, N. D. Mermin. Solid State Physics (1976)

   Holt, Rinehart and Winston · book, no DOI · record