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maximum efficiency reported near a 70 °C hot-water bath with ambient acting as the heat sink","sources":["source:sma-heat-engine-2019"],"year":2019}]},"environment":["state-solid","temp-gradient-required"],"summary":"NiTi elements cycled between warm and cold baths turn a shaft that drives a generator; a low-grade-heat engine with no working fluid.","review":{"canonical":true,"last_reviewed":"2026-09-20","reviewer":"loop-3 pass 7 audit (ChatGPT review, applied and source-verified by the lane)"},"route_id":"p-16d5bebae9","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/16d5bebae9"},{"id":"pathway:shape-memory-actuator","name":"Shape-memory heat engine (mechanical)","steps":["claim:temperature-drives-shape-memory","claim:shape-memory-produces-motion","claim:motion-converts-mechanical-work"],"demonstrated_with":["transducer:shape-memory-heat-engine"],"evidence":["source:otsuka-wayman-1998","source:sma-heat-engine-2019"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","environment":["state-solid","temp-gradient-required"],"summary":"The same engine delivering shaft work directly (Banks engine, 1973, and successors).","review":{"canonical":true,"last_reviewed":null},"route_id":"p-80569e3351","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/80569e3351"},{"id":"pathway:thermo-osmotic-energy-converter","name":"Thermo-osmotic energy conversion (TOEC)","steps":["claim:temperature-drives-thermo-osmosis","claim:thermo-osmosis-produces-flow","claim:fluid-flow-carrier-drives-lift","claim:lift-produces-motion","claim:motion-converts-mechanical-work"],"demonstrated_with":["transducer:thermo-osmotic-energy-converter"],"evidence":["source:straub-2016-toec"],"status":"proposed","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K5","performance":{"notes":"Every TOEC power density on record (Kuipers 2014 MemPower, Straub 2016, Li 2021 stack, Zhao 2021 PRMD) is the pressure × flux of the pressurised permeate, not turbine output. The one physical run through a hydro-turbine (Xiao et al. 2024, a 2 W-rated bulb lit) stored the permeate in an elevated tank first, a longer chain through gravitational head conversion; the direct coupling of a turbine to the pressurised permeate has not been reported (route search of 21/09/2026).","measurements":[{"quantity":"hydraulic power density","value":"3.53 ± 0.29 W/m² of membrane","value_numeric":3.53,"unit":"W/m²","metric":"power-density","basis":"pressure × permeate flux per membrane area; the turbine stage proposed, not run","normalization":{"kind":"area","basis":"membrane-area"},"scope":"laboratory","conditions":"60 °C hot side, 20 °C cold side, hydraulic pressures up to 13 bar; the pressurised flow was measured, the turbine stage is proposed","sources":["source:straub-2016-toec"],"year":2016}]},"environment":["state-liquid","medium-membrane","temp-gradient-required"],"summary":"Heat drives a thermo-osmotic vapour flux through a hydrophobic membrane into a pressurised reservoir; the pressurised flow is recorded, its conversion through a turbine is the proposed step.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 21 (TOEC route search: status kept proposed — the only turbine run, Xiao 2024, is a longer chain through gravitational storage)"},"route_id":"p-8fba925ce8","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/8fba925ce8"},{"id":"pathway:bimetal-piezoelectric-harvester","name":"Bimetallic-strip piezoelectric harvester","steps":["claim:thermal-expansion-drives","claim:thermal-expansion-produces-stress","claim:piezo-drives","claim:piezo-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":["transducer:bimetal-piezo-harvester"],"evidence":["source:boughaleb-2016-bimetal-piezo"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","performance":{"notes":"microwatt-scale electrical output per snap in laboratory devices; the strip's snap-through converts a slow thermal cycle into an impulse the piezoelectric element can use","measurements":[]},"environment":["state-solid","temp-gradient-required"],"summary":"A bimetallic strip snapping between hot and cold plates strikes a piezoelectric element; a demonstrated thermal-to-electrical harvester with no working fluid.","review":{"canonical":true,"last_reviewed":"2026-09-20","reviewer":"loop-3 pass 10 (frontier as a research instrument)"},"route_id":"p-c90dc55146","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/c90dc55146"},{"id":"pathway:forced-circulation-heat-delivery","name":"Forced-circulation heat-delivery loop","steps":["claim:temperature-drives-advective-heat-transport","claim:advective-heat-transport-produces-heat-flow","claim:heat-flow-converts-useful-heat"],"demonstrated_with":[],"evidence":["source:doe-hdbk-1012-2-92","source:nrc-pressurized-water-reactors"],"status":"commercial","regime_provides":["flow:bulk-fluid-motion"],"regime_model_provides":[],"auxiliary_requirements":[{"kind":"external-input","energy_form":"mechanical","purpose":"circulation pump","establishes":["flow:bulk-fluid-motion"],"conditions":["external pump or equivalent circulation machinery maintains bulk motion of the heat-carrying fluid through the hot and cold regions"],"evidence":["source:doe-hdbk-1012-2-92"],"note":"mechanical because that is the work supplied to the fluid; an implementation may obtain the shaft work electrically (the PWR's reactor coolant pumps do)"}],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","environment":["flow-required","temp-gradient-required"],"summary":"A pumped fluid carries enthalpy from a hot region to a cold one and delivers it as useful heat — forced convection in the DOE handbook's sense, the fluid motion caused by an outside force such as a pump, with the pumped heat exchanger as its canonical example and a reactor's primary coolant loop as a commercial one. A transport subsystem, not a converter: thermal in, thermal out.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 41 (the second reader's findings 14–19; DOE-HDBK-1012/2-92 read)"},"route_id":"p-e6101d69e3","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/e6101d69e3"},{"id":"pathway:thermocapillary-micromotor","name":"Thermocapillary micromotor","steps":["claim:temperature-drives-marangoni","claim:marangoni-produces-motion","claim:motion-converts-mechanical-work"],"demonstrated_with":["transducer:thermocapillary-micromotor"],"evidence":["source:maggi-2015-thermocapillary-gears"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K5","performance":{"measurements":[{"quantity":"rotation rate","value":"up to 300 r.p.m.","scope":"device","conditions":"microfabricated asymmetric gears on a liquid–air interface under wide-field incoherent illumination; the temperature gradient that drives the thermocapillary flow is produced by the light the gear absorbs","sources":["source:maggi-2015-thermocapillary-gears"],"year":2015,"note":"rotational work against viscous drag; no load other than the fluid was measured"}]},"environment":["state-liquid","temp-gradient-required"],"summary":"Absorbed light heats an asymmetric floating gear unevenly; the surface-tension gradient around it drives a thermocapillary flow whose stress torques the gear. The temperature gradient is the driver; light is how it is prepared.","review":{"canonical":true,"last_reviewed":"2026-09-20","reviewer":"loop-3 pass 16 (frontier candidates audited as physics; source read)"},"route_id":"p-eabf9fa870","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/eabf9fa870"},{"id":"pathway:marangoni-rotor","name":"Solutocapillary Marangoni rotor","steps":["claim:surface-drives-marangoni","claim:marangoni-produces-motion","claim:motion-converts-mechanical-work"],"demonstrated_with":["transducer:marangoni-rotor-generator"],"evidence":["source:frenkel-2019-marangoni-generator"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K5","performance":{"measurements":[{"quantity":"duration of rotation","value":"≈ 10–20 h","scope":"device","conditions":"floating polymer rotor with camphor engines on deionised water in a 420 mm dish","sources":["source:frenkel-2019-marangoni-generator"],"year":2019}]},"environment":["state-liquid"],"summary":"Camphor released from a floating rotor lowers the surface tension asymmetrically; the solutocapillary stress spins the rotor for hours — the camphor boat as a rotor.","review":{"canonical":true,"last_reviewed":"2026-09-20","reviewer":"loop-3 pass 16 (frontier candidates audited as physics; source read)"},"route_id":"p-90356c5582","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/90356c5582"},{"id":"pathway:marangoni-rotor-generator","name":"Marangoni rotor mini-generator","steps":["claim:surface-drives-marangoni","claim:marangoni-produces-motion","claim:motion-drives-induction","claim:induction-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:marangoni-rotor-generator"],"evidence":["source:frenkel-2019-marangoni-generator"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K5","performance":{"measurements":[{"quantity":"load voltage","value":"1.6 mV maximum across 35 Ω","scope":"device","conditions":"permanent magnets on the rotor passing a stationary 800-turn copper coil (r = 35 Ω) connected to a 35 Ω resistor; about 7 × 10⁻⁸ W at the maximum","sources":["source:frenkel-2019-marangoni-generator"],"year":2019,"note":"the power figure is derived from the reported voltage and resistance, not reported directly"}]},"environment":["state-liquid","medium-conductor","field-magnetic-required"],"summary":"The solutocapillary rotor carries permanent magnets whose passage induces a current in a stationary coil; a mini-generator run by a surface-energy difference alone.","review":{"canonical":true,"last_reviewed":"2026-09-20","reviewer":"loop-3 pass 16 (frontier candidates audited as physics; source read)"},"route_id":"p-699343a676","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/699343a676"},{"id":"pathway:thermo-driven-nanofluidic-converter","name":"Thermo-driven nanofluidic electrokinetic converter","steps":["claim:temperature-drives-thermo-osmosis","claim:thermo-osmosis-couples-streaming","claim:streaming-produces-ions","claim:ionic-current-converts-electricity"],"demonstrated_with":["transducer:thermo-driven-nanofluidic-converter"],"evidence":["source:zhao-2020-thermo-nanofluidics"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K4","performance":{"measurements":[{"quantity":"streaming current","value":"14 nA at ΔT = 47.5 °C","scope":"device","conditions":"track-etched polyimide membrane, 0.5 cm² exposed area, between hot and cold reservoirs; current rising linearly with ΔT, direction set by the surface charge (pH)","sources":["source:zhao-2020-thermo-nanofluidics"],"year":2020,"note":"a measured short-circuit current; the electrical power (25.48 pW per channel at ΔT = 40 °C in the paper) is calculated, not delivered to a load"}]},"environment":["state-liquid","medium-membrane","env-aqueous","temp-gradient-required"],"summary":"Thermo-osmotic flow through charged nanochannels carries the double-layer counter-ions; the streaming current is the electrical output. The composition the atlas's first reviewed search found, recorded as the device it is.","review":{"canonical":true,"last_reviewed":"2026-09-20","reviewer":"loop-3 pass 16 (frontier candidates audited as physics; mechanism read in pass 13)"},"route_id":"p-a9a16d56d9","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/a9a16d56d9"},{"id":"pathway:thermomagnetic-hydrodynamic-harvester","name":"Thermomagnetic hydrodynamic energy harvester","steps":["claim:temperature-drives-ferrofluid-convection","claim:ferrofluid-convection-couples-induction","claim:induction-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:thermomagnetic-hydrodynamic-harvester"],"evidence":["source:chiolerio-2020-thermomagnetic-harvester"],"status":"prototype","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","performance":{"measurements":[{"quantity":"extracted electrical power per kelvin","value":"up to 10.4 μW/K","scope":"laboratory","conditions":"toroidal closed loop, commercial ferrofluid packets in a water carrier, Peltier-controlled gradient, permanent magnets, poloidal or mixed poloidal/toroidal induction windings","sources":["source:chiolerio-2020-thermomagnetic-harvester"],"year":2020}]},"environment":["state-liquid","field-magnetic-required","temp-gradient-required","medium-conductor"],"summary":"A ferrofluid advects around a torus as heating demagnetises it; coils wound on the torus see the passing magnetised packets and deliver electrical power directly, with no moving solid part.","review":{"canonical":true,"last_reviewed":"2026-09-20","reviewer":"loop-3 pass 16 (frontier candidates audited as physics; source read)"},"route_id":"p-1a7aae88b9","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/1a7aae88b9"},{"id":"pathway:thermomagnetic-fluid-engine","name":"Thermomagnetic fluid engine","steps":["claim:temperature-drives-ferrofluid-convection","claim:ferrofluid-convection-produces-flow","claim:fluid-flow-carrier-drives-lift","claim:lift-produces-motion","claim:motion-converts-mechanical-work"],"demonstrated_with":["transducer:thermomagnetic-fluid-engine"],"evidence":["source:zhou-2009-thermomagnetic-engine"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K5","performance":{"measurements":[{"quantity":"rotor angular velocity","value":"≈ 2.1 rad/min peak","scope":"device","conditions":"kerosene-based temperature-sensitive magnetic fluid, permanent NdFeB magnet, rotor in the circulating fluid; speed rises with heat input and with a colder heat sink","sources":["source:zhou-2009-thermomagnetic-engine"],"year":2009,"note":"no shaft power reported; a miniature demonstration of the mechanism"}]},"environment":["state-liquid","field-magnetic-required","temp-gradient-required"],"summary":"Thermomagnetic convection of a magnetic fluid in a permanent-magnet field circulates the fluid, and the circulating fluid turns a rotor — the produced flow loading a blade, which is why the atlas records it on the flow-to-rotor spelling rather than as a direct effect.","review":{"canonical":true,"last_reviewed":"2026-09-20","reviewer":"loop-3 pass 16 (frontier candidates audited as physics; source read)"},"route_id":"p-46303b9eaf","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/46303b9eaf"},{"id":"pathway:pneumatic-pressure-piezo-harvester","name":"Pneumatic pressure piezoelectric harvester","steps":["claim:pressure-drives-elastic","claim:elastic-produces-stress-carrier","claim:elastic-stress-drives-piezo","claim:piezo-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":["transducer:pneumatic-pressure-piezo-harvester"],"evidence":["source:yang-2022-pneumatic-piezo-harvester"],"status":"prototype","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K5","performance":{"measurements":[{"quantity":"peak power","value":"140 μW at 1500 kΩ","value_numeric":0.00014,"unit":"W","metric":"power","basis":"peak electrical power into the optimal 1500 kΩ load during a pressure excursion","scope":"device","conditions":"air pressure varying from 0 to 0.5 MPa on a sealed piezoelectric harvester connected to a pneumatic branch pipe; transient, alternating output","sources":["source:yang-2022-pneumatic-piezo-harvester"],"year":2022},{"quantity":"power density","value":"1.43 mW cm⁻³","value_numeric":1.43,"unit":"mW/cm³","metric":"power-density","basis":"peak power per unit volume of the harvester (the authors' volumetric normalisation), at the maximum peak power","normalization":{"kind":"volume","basis":"device-volume"},"scope":"device","conditions":"same excursion and load","sources":["source:yang-2022-pneumatic-piezo-harvester"],"year":2022}]},"environment":["state-solid","medium-non-centrosymmetric"],"summary":"The pressure excursions of a pneumatic line stress a sealed piezoelectric element, which delivers transient electrical power; the pressure gradient is engineered, so this is a harvester of an existing system's swings, not a primary source.","review":{"canonical":true,"last_reviewed":"2026-09-20","reviewer":"loop-3 pass 16 (frontier candidates audited as physics; source read)"},"route_id":"p-0a2f6363df","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/0a2f6363df"},{"id":"pathway:wave-impact-piezo-harvester","name":"Wave-impact piezoelectric harvester","steps":["claim:wave-drives","claim:wave-produces-pressure","claim:pressure-drives-elastic","claim:elastic-produces-stress-carrier","claim:elastic-stress-drives-piezo","claim:piezo-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":["transducer:wave-impact-piezo-harvester"],"evidence":["source:mozumder-2026-wave-impact-piezo"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K5","performance":{"measurements":[{"quantity":"open-circuit voltage per pipe","value":"up to 1.28 V","scope":"laboratory","conditions":"stacked PZT-5A discs struck by 70 g steel impact balls on rigid cement base tiles, double-disc configuration; simulated waves at 0.1–2 Hz, 3.5 % salinity","sources":["source:mozumder-2026-wave-impact-piezo"],"year":2026},{"quantity":"power per wave event","value":"≈ 20 mW","scope":"laboratory","conditions":"same configuration; reported per wave event, not as a time average","sources":["source:mozumder-2026-wave-impact-piezo"],"year":2026,"note":"one laboratory demonstration in a conference series; the atlas records it as demonstrated, not replicated"}]},"environment":["state-liquid","state-solid","medium-non-centrosymmetric"],"summary":"Wave motion drives impact balls against stacked piezoelectric discs; the impact stress is the pressure step the atlas records between wave motion and elastic deformation, a coarse but faithful spelling of impact loading.","review":{"canonical":true,"last_reviewed":"2026-09-20","reviewer":"loop-3 pass 16 (frontier candidates audited as physics; source read)"},"route_id":"p-e08b54945e","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/e08b54945e"},{"id":"pathway:thermocapillary-streaming-generator","name":"Thermocapillary streaming-potential generator (proposed)","steps":["claim:temperature-drives-marangoni","claim:marangoni-produces-flow","claim:fluid-flow-carrier-drives-streaming","claim:streaming-produces-ions","claim:ionic-current-converts-electricity"],"demonstrated_with":[],"evidence":["source:pini-2015-surface-tension-streaming"],"status":"proposed","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K3","performance":{"notes":"Pini, Baier and Dietzel (2015) compare the maximal thermal efficiency of the thermocapillary drive with the Carnot value and find it limited by the heat capacity of aqueous solvents — the source's own analysis, not a bound of the atlas.","measurements":[]},"environment":["state-liquid","env-aqueous","temp-gradient-required","charged-surface-required"],"summary":"A temperature gradient along a free electrolyte surface drives a thermocapillary shear flow past a charged wall, whose streaming potential is the electrical output. Analysed theoretically and numerically; no physical demonstration is recorded, so the route stays a candidate.","review":{"canonical":true,"last_reviewed":"2026-09-20","reviewer":"loop-3 pass 16 (frontier candidates audited as physics; abstract read)"},"route_id":"p-423a19acdd","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/423a19acdd"},{"id":"pathway:solutocapillary-streaming-generator","name":"Solutocapillary streaming-potential generator (proposed)","steps":["claim:surface-drives-marangoni","claim:marangoni-produces-flow","claim:fluid-flow-carrier-drives-streaming","claim:streaming-produces-ions","claim:ionic-current-converts-electricity"],"demonstrated_with":[],"evidence":["source:pini-2015-surface-tension-streaming","source:zhang-2026-marangoni-hydrovoltaic"],"status":"proposed","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K3","performance":{"notes":"Pini, Baier and Dietzel (2015) find concentration-driven (destillocapillary) flows more promising than thermocapillary ones — a finding of the source, not a bound. Zhang et al. 2026 physically demonstrated a graphene-oxide evaporator in which a programmed chemical/surface-tension gradient sustained Marangoni microcirculation alongside capillary flow while the device delivered 25 μA short-circuit current, 0.7 V open-circuit voltage and powered an LED. Route review: driver-only-modifies because capillary and Marangoni transport are simultaneous co-drivers and the electrical contribution of the Marangoni branch was not isolated. Its figures belong to the combined device and are not recorded here.","measurements":[]},"environment":["state-liquid","env-aqueous","charged-surface-required"],"summary":"A surfactant-concentration difference along a free electrolyte surface drives a solutocapillary shear flow past a charged wall, whose streaming potential is the electrical output. Theoretical and numerical only; the route stays a candidate — the nearest physical device (Zhang 2026) runs the Marangoni flow as a co-driver beside capillary transport.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 22 (Zhang 2026 abstract read; the co-driver device recorded as a note under the parallel-driver rule)"},"route_id":"p-41cb505083","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/41cb505083"},{"id":"pathway:flexoelectric-vibration-harvester","name":"Flexoelectric vibration harvester","steps":["claim:vibration-drives-elastic","claim:elastic-produces-stress","claim:flexo-drives","claim:flexo-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":["transducer:flexoelectric-vibration-harvester"],"evidence":["source:yang-2025-flexoelectric-harvester"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K5","performance":{"measurements":[{"quantity":"output voltage","value":"≈ 0.19 V average","value_numeric":0.19,"unit":"V","scope":"laboratory","conditions":"two-stage stepped epoxy cantilever with an unpolarised α-PVDF flexoelectric layer (60 × 10 mm, 45 μm) on a vibration exciter, sinusoidal 20 Hz, measured acceleration 0.915 g; off resonance (the 1.2 Hz resonance was beyond the shaker)","sources":["source:yang-2025-flexoelectric-harvester"],"year":2025,"note":"the paper's 3.58 V and 94.93 mW m⁻³ at resonance are theory and finite elements, not measurements, and are not recorded here"}]},"environment":["state-solid","medium-dielectric"],"summary":"Base vibration bends a dielectric cantilever; the bending strain gradient, not piezoelectricity, polarises the unpolarised PVDF layer and the electrodes deliver charge to a load. Demonstrated off resonance; resonance is an amplifying operating condition, not a step of the composition.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 20 (the last two candidate compositions audited as physics; source read in full)"},"route_id":"p-7b4c3afd6f","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/7b4c3afd6f"},{"id":"pathway:vibration-elastocaloric-cooler","name":"Vibration-driven elastocaloric cooler (proposed)","steps":["claim:vibration-drives-elastic","claim:elastic-produces-stress","claim:elastocaloric-drives","claim:elastocaloric-converts-cooling"],"demonstrated_with":["transducer:vibration-elastocaloric-cooler"],"evidence":["source:kumar-2019-vibration-refrigeration"],"status":"proposed","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K3","performance":{"measurements":[{"quantity":"predicted source cooling (finite-element model)","value":"≈ 0.2 K in ≈ 50 s","datum_kind":"simulated","scope":"model","conditions":"ten cantilevers with off-axis 0.5BZT–0.5BCT patches, 2 mm imposed tip motion, 324 K, 1.5 Hz; 0.02 K per element; ≈ 2 K predicted from 358 K","sources":["source:kumar-2019-vibration-refrigeration"],"year":2019,"note":"model-only; no device has been built or measured"}]},"environment":["state-solid"],"summary":"Ambient vibration stresses off-axis ferroelectric patches on a cantilever elastocalorically and periodic contacts carry the heat away — proposed and modelled by finite elements, never built. The genuine open question behind this route is whether ambient vibration supplies enough stress, timing and heat transfer for sustained cooling.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 20 (the last two candidate compositions audited as physics; abstract read)"},"route_id":"p-4d6800fa81","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/4d6800fa81"},{"id":"pathway:bending-actuated-elastocaloric-cooler","name":"Bending-actuated NiTi elastocaloric air cooler","steps":["claim:elastocaloric-drives","claim:elastocaloric-converts-cooling"],"demonstrated_with":["transducer:bending-elastocaloric-air-cooler"],"evidence":["source:li-2022-bending-elastocaloric"],"status":"demonstrated","regime_provides":["mechanical:stress-change","mechanical:stress-crosses-transformation-threshold","mechanical:stress-cycling"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","performance":{"measurements":[{"quantity":"air temperature reduction","value":"5.5 K","value_numeric":5.5,"unit":"K","scope":"device","conditions":"single-row bent NiTi sheets with an air duct, cooling cycle; 7.20 % maximum surface strain on the tension side at a specific driving force of 5.64 N g⁻¹","sources":["source:li-2022-bending-elastocaloric"],"year":2022},{"quantity":"specific cooling power","value":"0.137 W g⁻¹","value_numeric":0.137,"unit":"W/g","scope":"device","conditions":"same single-row cooler","sources":["source:li-2022-bending-elastocaloric"],"year":2022},{"quantity":"cooling power","value":"11.5 W","value_numeric":11.5,"unit":"W","scope":"device","conditions":"multi-row NiTi sheets","sources":["source:li-2022-bending-elastocaloric"],"year":2022}]},"environment":["state-solid"],"summary":"An actuator bends NiTi sheets through their transformation at two orders of magnitude less force than tension; the recorded driver is mechanical stress supplied by the actuator, which is why this pathway starts at the stress row and is not evidence that ambient vibration can drive the cooler.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 20 (the last two candidate compositions audited as physics; abstract read)"},"route_id":"p-da3558eaf6","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/da3558eaf6"},{"id":"pathway:thermal-osmosis-electrokinetic-generator","name":"Thermal-osmosis electrokinetic generator","steps":["claim:temperature-drives-thermo-osmosis","claim:thermo-osmosis-produces-flow","claim:fluid-flow-carrier-drives-streaming","claim:streaming-produces-ions","claim:ionic-current-converts-electricity"],"demonstrated_with":["transducer:thermal-osmosis-electrokinetic-generator"],"evidence":["source:huang-2021-membrane-distiller-electrokinetic","source:luo-2023-thermal-osmosis-electrokinetic"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K5","performance":{"measurements":[{"quantity":"electrical output power density","value":"1.12 W/m²","value_numeric":1.12,"unit":"W/m²","metric":"power-density","basis":"as reported in the abstract; the area basis is not stated there","normalization":{"kind":"area","basis":"unstated"},"scope":"laboratory","conditions":"thermal-osmosis PTFE membrane (1.0 μm pores) plus an electrokinetic microchannel module; ΔT = 50 °C; real seawater feed","sources":["source:luo-2023-thermal-osmosis-electrokinetic"],"year":2023},{"quantity":"freshwater production rate","value":"18.46 kg/m²·h","value_numeric":18.46,"unit":"kg/(m²·h)","scope":"laboratory","conditions":"the same device and run; ΔT = 50 °C","sources":["source:luo-2023-thermal-osmosis-electrokinetic"],"year":2023,"note":"the co-product, recorded because the source reports the two together; not an energy figure"}]},"environment":["state-liquid","medium-membrane","env-aqueous","temp-gradient-required","charged-surface-required"],"summary":"A temperature difference drives vapour transport through a hydrophobic membrane, producing pressurised fresh water; the water then traverses a charged electrokinetic microchannel module and delivers electrical power — the explicit-flow spelling of the nanofluidic thermo-osmotic converter, with a bulk stream between the two mechanisms.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 21 (TOEC route search; abstracts read; Huang 2021's figures not recorded until its text is read)"},"route_id":"p-194168115f","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/194168115f"},{"id":"pathway:combustion-microthermophotovoltaic-generator","name":"Combustion-driven micro-thermophotovoltaic generator","steps":["claim:combustion-drives","claim:combustion-produces-hot-gas","claim:hot-gas-drives-thermal-emission","claim:thermal-emission-produces-photons","claim:photons-drive-pv","claim:pv-produces-pairs","claim:pairs-convert-electricity"],"demonstrated_with":["transducer:micro-thermophotovoltaic-generator"],"evidence":["source:chan-2013-microthermophotovoltaic"],"status":"demonstrated","regime_provides":["light:above-bandgap-photon-flux"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","performance":{"measurements":[{"quantity":"heat-to-electricity efficiency","value":"2.5 %","value_numeric":0.025,"unit":"1","metric":"conversion-efficiency","basis":"electrical output of the generator (after its maximum-power-point converter) over the 13.7 W input thermal power to the propane microcombustor the abstract states — the fuel's heat release, which under complete combustion is the route's chemical input; the abstract calls the figure heat-to-electricity (pass 45)","scope":"laboratory","conditions":"propane microcombustor at up to 800 °C; photonic-crystal selective emitter; four 0.55 eV GaInAsSb cells with maximum-power-point tracking; the simplified system predicted at 2.7 %","sources":["source:chan-2013-microthermophotovoltaic"],"year":2013},{"quantity":"electrical power density","value":"344 mW over 1 cm²","value_numeric":3440,"unit":"W/m²","metric":"power-density","basis":"electric power per emitter/cell area","normalization":{"kind":"area","basis":"active-device-area"},"scope":"laboratory","conditions":"the same run; 13.7 W thermal input","sources":["source:chan-2013-microthermophotovoltaic"],"year":2013}]},"environment":["state-gas","temp-gradient-required"],"summary":"Fuel burns in a microcombustor, the hot gas heats a selective emitter, and the emitter's thermal radiation is converted by low-bandgap photovoltaic cells — the combustion-fed cousin of the thermophotovoltaic pathway, recorded as its own composition because its driver is chemical, not a temperature gradient supplied from outside.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 22 (Scholar runs, the parallel-driver rule and the head rule; abstract read)"},"route_id":"p-7b7ac74cb0","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/7b7ac74cb0"},{"id":"pathway:radioluminescent-nuclear-battery","name":"Radioluminescent (beta-photovoltaic) nuclear battery","steps":["claim:binding-drives-decay","claim:decay-produces-particles","claim:beta-drives-radioluminescence","claim:radioluminescence-produces-photons","claim:photons-drive-pv","claim:pv-produces-pairs","claim:pairs-convert-electricity"],"demonstrated_with":["transducer:radioluminescent-nuclear-battery"],"evidence":["source:russo-2017-radioluminescent-nuclear-battery"],"status":"demonstrated","regime_provides":["light:above-bandgap-photon-flux"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","performance":{"measurements":[{"quantity":"total power conversion efficiency","value":"0.289 %","value_numeric":0.00289,"unit":"1","metric":"conversion-efficiency","basis":"electrical output over the β⁻ source power, volumetric configuration at 15 mCi ⁶³Ni and 200 μm","scope":"laboratory","conditions":"⁶³Ni chloride solution mixed with ZnS:Cu,Al phosphor on an InGaP cell; the planar configuration reached 0.0638 % at 50 μm","sources":["source:russo-2017-radioluminescent-nuclear-battery"],"year":2017},{"quantity":"electrical power density","value":"3.35 nW/cm²","value_numeric":0.0000335,"unit":"W/m²","metric":"power-density","basis":"electrical power per cell area at 30 mCi ⁶³Ni","normalization":{"kind":"area","basis":"active-device-area"},"scope":"laboratory","conditions":"volumetric configuration","sources":["source:russo-2017-radioluminescent-nuclear-battery"],"year":2017}]},"environment":["state-solid"],"summary":"A β⁻ emitter excites a phosphor and a photovoltaic cell matched to the phosphor's spectrum converts the light — the indirect (scintillator) nuclear battery, distinct from the betavoltaic cell that absorbs the electrons directly.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 22 (Scholar runs, the parallel-driver rule and the head rule; abstract read)"},"route_id":"p-44d21685a3","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/44d21685a3"},{"id":"pathway:evaporation-driven-generator","name":"Evaporation-driven oscillator generator","steps":["claim:humidity-drives-evaporation","claim:evaporation-produces-motion","claim:motion-drives-induction","claim:induction-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:evaporation-driven-generator"],"evidence":["source:chen-2015-evaporation"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","performance":{"measurements":[{"quantity":"electrical power (burst peak)","value":"60 μW","value_numeric":0.00006,"unit":"W","scope":"laboratory","conditions":"oscillatory HYDRA engine coupled to an electromagnetic generator, 100 kΩ load, water at 30 °C, HYDRAs covering 9.6 cm × 7.6 cm","sources":["source:chen-2015-evaporation"],"year":2015},{"quantity":"electrical power (time average)","value":"1.8 μW","value_numeric":0.0000018,"unit":"W","scope":"laboratory","conditions":"the same run; waiting periods between bursts bring the average down","sources":["source:chen-2015-evaporation"],"year":2015,"note":"per the authors, the microwatt scale is significant for the small water area covered; power density is not stated per area"}]},"environment":["env-aqueous"],"summary":"Evaporation from a water surface drives hygroscopic artificial muscles in a shutter-controlled oscillator whose piston-like motion turns an electromagnetic generator — the evaporation-driven engine's electrical sibling, recorded on the induction spelling because the generator is a magnet stack rotating between coils.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 23 (triage of the released candidates; source read in full)"},"route_id":"p-afcf48bf79","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/afcf48bf79"},{"id":"pathway:thermocapillary-piezoelectric-micro-heat-engine","name":"Thermocapillary piezoelectric micro heat engine","steps":["claim:temperature-drives-marangoni","claim:marangoni-produces-pressure","claim:pressure-drives-elastic","claim:elastic-produces-stress-carrier","claim:elastic-stress-drives-piezo","claim:piezo-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":[],"evidence":["source:glockner-naterer-2006-thermocapillary-pumping","source:odukoya-naterer-2013-thermocapillary-mhe","source:glockner-naterer-2007-microfluidic-power"],"status":"proposed","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K3","performance":{"measurements":[{"quantity":"predicted output voltage","value":"1.2–1.3 mV","value_numeric":0.00125,"unit":"V","datum_kind":"simulated","scope":"model","conditions":"simulated closed 60 × 60 × 15,000 μm channel on a PZT substrate, the thickest membrane; 0.5 mV predicted for a 300 nm membrane","sources":["source:odukoya-naterer-2013-thermocapillary-mhe"],"year":2013,"note":"a model result, never a laboratory measurement"},{"quantity":"predicted system efficiency","value":"≈ 1.6 %","value_numeric":0.016,"unit":"1","metric":"conversion-efficiency","basis":"analytical model with the electromechanical coupling factor and frictional irreversibilities, over the range of displacement considered","datum_kind":"simulated","scope":"model","conditions":"the same simulated geometry","sources":["source:odukoya-naterer-2013-thermocapillary-mhe"],"year":2013,"note":"a model result, never a laboratory measurement"}]},"environment":["state-liquid"],"summary":"A temperature gradient drives a confined droplet by thermocapillarity; the translating plug compresses trapped gas, and the resulting pressure is proposed to flex a PZT membrane and generate electricity. The thermocapillary pumping was experimentally characterised; membrane voltage and full-cycle efficiency were modelled rather than measured.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 23 (triage of the released candidates; Odukoya 2013 read in full; recorded proposed at K3 because the composition itself has not been observed)"},"route_id":"p-b7667759aa","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/b7667759aa"},{"id":"pathway:waterwheel-electric-generator","name":"Waterwheel electric generator (pico hydro)","steps":["claim:gravity-drives-descent","claim:descent-produces-waterwheel-motion","claim:motion-drives-induction","claim:induction-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:waterwheel-generator"],"evidence":["source:asim-2022-pico-waterwheel"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K7","performance":{"measurements":[{"quantity":"electrical load powered","value":"1.54 kW of appliances on a 3 kW generator","value_numeric":1540,"unit":"W","scope":"field","conditions":"undershot pico waterwheel, C-shape blades immersed 4 inches, in an irrigation-channel test rig; voltage and current measured at full load (three 100 W bulbs, two 120 W fans, a 1 kW cutting machine)","sources":["source:asim-2022-pico-waterwheel"],"year":2022,"note":"the connected load the generator ran, as the paper lists it; the generator's measured electrical output is not quoted here"},{"quantity":"overall efficiency of the waterwheel-generator system","value":"66.42%","value_numeric":0.6642,"unit":"1","metric":"conversion-efficiency","basis":"generator electrical output P_out = v_g·i_g over P_in, as Equation 12 defines the overall efficiency of the system (Section 4.9); the paper does not state P_in's formula at that point — Equation 11's power coefficient uses the power available in the stream, but Section 4.9 does not say Equation 12's P_in is the same denominator","datum_kind":"measured","scope":"laboratory","conditions":"the C-shape-blade experimental turbine at a fully immersed depth of 4 inches, connected to a 3 kW electric generator, at full load, voltage and current of the circuit measured","sources":["source:asim-2022-pico-waterwheel"],"year":2022,"note":"the number the paper itself measured; the 66.42 % is an electrical-output figure for the wheel plus generator, the pathway's own boundary"}]},"environment":["state-liquid"],"summary":"Water falling through a small head turns an undershot waterwheel whose shaft directly turns an electrical generator — the oldest hydroelectric spelling, distinct from the turbine's blade lift, recorded on the direct waterwheel-to-induction route with a pico-hydro rig that ran household loads.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 23 (triage of the released candidates; Asim 2022 read on the publisher's page)"},"route_id":"p-84d6235b69","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/84d6235b69"},{"id":"pathway:thermal-expansion-flexoelectric-response","name":"Thermal-expansion flexoelectric thermopolarization","steps":["claim:thermal-expansion-drives","claim:thermal-expansion-produces-stress","claim:flexo-drives","claim:flexo-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":[],"evidence":["source:iwakiri-2026-thermopolarization"],"status":"observed","observed_through":"claim:flexo-produces-charge","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K4","performance":{"notes":"No output power, efficiency or harvested energy is reported; the finite-element temperature modulation (≈ 0.5 K at the 1 kHz heater drive) is model scope and is not recorded as a measurement.","measurements":[]},"environment":["state-solid","medium-dielectric","temp-gradient-required"],"summary":"A spatial temperature gradient produces non-uniform thermal expansion and a strain gradient that drives flexoelectric polarization in insulating solids. Voltage and polarization-screening current were experimentally detected, but no electrical load or output power was reported, so heat-to-charge conversion is observed while electrical-work conversion remains undemonstrated. Thermopolarization names the measured ∇T-induced polarization, not a unique microscopic mechanism — Iwakiri et al. attribute their component to thermomechanical flexoelectricity because it scales with thermal expansion and a strain-gradient FEM reproduces it, while the historical \"proper\" thermopolarization (the atlas's separate phenomenon) is the direct residual response distinguished from that contribution.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 24 (the second reader's status (a) — observed, observed_through the flexoelectric charge step; the final step remains unsupported by the evidence)"},"route_id":"p-a093d7ecc5","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/a093d7ecc5"},{"id":"pathway:thermoacoustic-piezoelectric-harvester","name":"Thermoacoustic piezoelectric harvester","steps":["claim:thermoacoustic-drives","claim:thermoacoustic-produces-sound","claim:acoustic-wave-drives-piezoelectric","claim:piezo-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":["transducer:thermoacoustic-piezoelectric-harvester"],"evidence":["source:zheng-2022-thermoacoustic-pan","source:smoker-2012-thermoacoustic-piezoelectric"],"status":"demonstrated","regime_provides":["thermal:gradient-above-thermoacoustic-critical"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","performance":{"measurements":[{"quantity":"open-circuit voltage (peak)","value":"102 V","value_numeric":102,"unit":"V","scope":"laboratory","conditions":"3 × 3 cm² thermally stabilised PAN nanofibre membrane in the sound field of a mini thermoacoustic engine, the device at 280 °C; ran 30 LEDs and charged a lithium battery and a capacitor; stable for at least 2 h","sources":["source:zheng-2022-thermoacoustic-pan"],"year":2022},{"quantity":"short-circuit current (peak)","value":"10 μA","value_numeric":0.00001,"unit":"A","scope":"laboratory","conditions":"the same engine-driven run","sources":["source:zheng-2022-thermoacoustic-pan"],"year":2022},{"quantity":"areal power density","value":"392 mW m⁻²","value_numeric":0.392,"unit":"W/m²","scope":"laboratory","conditions":"under loudspeaker sound, 118 dB at 230 Hz (118 V open-circuit, 12 μA short-circuit), room temperature to 450 °C — the device characterisation, not the engine-driven run","sources":["source:zheng-2022-thermoacoustic-pan"],"year":2022,"note":"abstract figures; the engine-driven output is the pathway's demonstration"}]},"environment":["state-gas","temp-gradient-required"],"summary":"A thermoacoustic engine's sound field strains a piezoelectric nanofibre membrane, whose charge runs a load — the piezoelectric sibling of the linear-alternator generator, recorded from the authors' engine-driven run. The authors call the membrane \"acoustoelectric\"; the atlas keeps that name for Weinreich carrier drag, a different coupling. The earlier demonstration is Smoker et al. 2012, a standing-wave resonator exciting a piezoelectric diaphragm, validated on a prototype without published output figures.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 25 (known device recorded from the abstract; the second reader ruled it wrong-coupling for the acoustoelectric route)"},"route_id":"p-e56e0f39ea","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/e56e0f39ea"},{"id":"pathway:thermoacoustic-triboelectric-harvester","name":"Thermoacoustic triboelectric harvester","steps":["claim:thermoacoustic-drives","claim:thermoacoustic-produces-sound","claim:acoustic-wave-drives-triboelectric","claim:tribo-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":["transducer:thermoacoustic-triboelectric-harvester"],"evidence":["source:li-2026-thermoacoustic-teng"],"status":"demonstrated","regime_provides":["thermal:gradient-above-thermoacoustic-critical"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","performance":{"measurements":[{"quantity":"electrical power (peak)","value":"0.49 mW","value_numeric":0.00049,"unit":"W","scope":"laboratory","conditions":"piston-assisted thermoacoustic engine driving a honeycomb freestanding contact-separation triboelectric nanogenerator at an 80 MΩ load; stable oscillation at heating temperatures around 150 °C","sources":["source:li-2026-thermoacoustic-teng"],"year":2026},{"quantity":"operating temperature","value":"≈ 150 °C heating","value_numeric":423,"unit":"K","scope":"laboratory","conditions":"the heating temperature at which the engine's self-sustained oscillation is stable","sources":["source:li-2026-thermoacoustic-teng"],"year":2026,"note":"storage observed separately, not recorded as power: four stacked units charged 1 μF to 17.05 V in 10 s and, with power management, ran a wireless temperature sensor"}]},"environment":["state-gas","temp-gradient-required"],"summary":"A thermoacoustic engine produces pressure oscillations that actuate a piston-coupled contact–separation triboelectric generator; the electrical output powers storage and a wireless sensor.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 27 (the second reader's spelling; the piston is apparatus at the gas–solid boundary, recorded as an interface)"},"route_id":"p-0004bd753a","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/0004bd753a"},{"id":"pathway:regenerative-elastocaloric-heat-pump","name":"Regenerative elastocaloric heat pump","steps":["claim:elastocaloric-drives","claim:elastocaloric-converts-heating"],"demonstrated_with":["transducer:regenerative-elastocaloric-heat-pump"],"evidence":["source:tusek-2016"],"status":"demonstrated","regime_provides":["mechanical:stress-change","mechanical:stress-crosses-transformation-threshold","mechanical:stress-cycling"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K7","performance":{"measurements":[{"quantity":"water-side temperature span","value":"15.3 K","value_numeric":15.3,"unit":"K","scope":"device","conditions":"regenerative elastocaloric heat pump with NiTi plates cycled through the superelastic transformation; water-side span between the hot and cold outlets","sources":["source:tusek-2016"],"year":2016},{"quantity":"specific heating power","value":"up to 800 W kg⁻¹","value_numeric":800,"unit":"W/kg","scope":"device","conditions":"the same device, per kilogram of elastocaloric material","sources":["source:tusek-2016"],"year":2016},{"quantity":"coefficient of performance (heating)","value":"up to 7","value_numeric":7,"scope":"device","conditions":"maximum COP reported for the same device","sources":["source:tusek-2016"],"year":2016}]},"environment":["state-solid"],"summary":"An active regenerator of superelastic NiTi plates, cycled through their stress-induced transformation, pumps heat across a 15.3 K water-side span with specific heating power up to 800 W per kilogram and COP up to 7 — the heat-pumping face of the elastocaloric effect, beside the bending-actuated cooler.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 31 (the second reader asked for Tušek 2016's regime on a pathway of its own; abstract read)"},"route_id":"p-3762928a7c","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/3762928a7c"},{"id":"pathway:thermoelectric-generator","name":"Thermoelectric generator","steps":["claim:seebeck-drives","claim:seebeck-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:thermoelectric-generator"],"evidence":["source:rowe-2006","source:snyder-toberer-2008","source:goldsmid-2016"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","performance":{"measurements":[{"quantity":"module conversion efficiency","value":"12.0%","value_numeric":0.12,"unit":"1","metric":"conversion-efficiency","basis":"module: electrical output over heat flow measured at the cold side","parameters":{"T_h_K":850,"T_c_K":300},"scope":"module","conditions":"Bi₂Te₃/skutterudite segmented 8-couple module, T_h = 850 K, T_c = 300 K (ΔT = 550 K), matched load; heat flow measured at the cold side","sources":["source:zhang-2017-segmented-teg"],"year":2017,"note":"record for a segmented module at the time of publication"}]},"environment":["state-solid","temp-gradient-required"],"summary":"Heat flows through n- and p-type legs; the Seebeck voltage drives the load. Used from radioisotope generators to waste-heat recovery.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-d4b83f7f17","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/d4b83f7f17"},{"id":"pathway:thermionic-converter","name":"Thermionic converter","steps":["claim:thermionic-drives","claim:thermionic-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:thermionic-converter"],"evidence":["source:hatsopoulos-gyftopoulos-1973"],"status":"prototype","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K7","environment":["env-vacuum","temp-high"],"summary":"A cathode above 1500 K emits electrons collected across a caesium-vapour gap; flown in space reactors.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-0354536226","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/0354536226"},{"id":"pathway:thermoacoustic-generator","name":"Thermoacoustic engine with linear alternator","steps":["claim:thermoacoustic-drives","claim:thermoacoustic-produces-sound","claim:acoustic-drives-linear-alternator","claim:linear-alternator-produces","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:thermoacoustic-engine"],"evidence":["source:swift-1988"],"status":"prototype","regime_provides":["thermal:gradient-above-thermoacoustic-critical"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K7","performance":{"measurements":[{"quantity":"thermal-to-electrical conversion efficiency at the maximum-efficiency point","value":"19.8%","value_numeric":0.198,"unit":"1","metric":"conversion-efficiency","basis":"electric power over heat input to the engine, as the abstract states it; the paper's heat-input measurement is not on record (abstract only)","datum_kind":"measured","parameters":{"T_h_K":923.15,"T_c_K":288.15},"scope":"laboratory","conditions":"1 kW-class travelling-wave thermoacoustic electrical generator with a linear alternator; 4.0 MPa mean pressure; 64 Hz after 4.5 % mole fraction argon; electric output 970 W at this point; heating 650 °C, cooling 15 °C","sources":["source:wu-2014-1kw-thermoacoustic-generator"],"year":2014},{"quantity":"maximum electric power","value":"1043 W","value_numeric":1043,"unit":"W","metric":"power","basis":"electric output at the maximum-power operating point","datum_kind":"measured","scope":"laboratory","conditions":"the same generator; 17.7 % thermal-to-electrical efficiency at this point, not the maximum efficiency","sources":["source:wu-2014-1kw-thermoacoustic-generator"],"year":2014},{"quantity":"thermal-to-electric conversion efficiency at the maximum-efficiency point","value":"18.4%","value_numeric":0.184,"unit":"1","metric":"conversion-efficiency","basis":"electric power over heat input to the engine, as the abstract states it; the paper's heat-input measurement is not on record (abstract only)","datum_kind":"measured","parameters":{"T_h_K":923.15,"T_c_K":298.15},"scope":"laboratory","conditions":"three-stage travelling-wave thermoacoustic electric generator, units joined end-to-end by slim resonance tubes with a linear alternator as a bypass at the end of each; 6 MPa pressurised helium; electric output 3.46 kW at this point; heating 650 °C, cooling 25 °C","sources":["source:bi-2017-5kw-thermoacoustic-generator"],"year":2017},{"quantity":"maximum electric power","value":"4.69 kW","value_numeric":4690,"unit":"W","metric":"power","basis":"electric output at the maximum-power operating point","datum_kind":"measured","scope":"laboratory","conditions":"the same three-stage generator; 15.6 % thermal-to-electric efficiency at this point, not the maximum efficiency","sources":["source:bi-2017-5kw-thermoacoustic-generator"],"year":2017}]},"environment":["state-gas","temp-gradient-required"],"summary":"Heat makes a gas column oscillate; the oscillation drives a piston in a coil.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-51df73df29","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/51df73df29"},{"id":"pathway:pyroelectric-harvester","name":"Pyroelectric harvester","steps":["claim:pyro-drives","claim:pyro-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":["transducer:pyroelectric-harvester"],"evidence":["source:bowen-2014-pyro"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","environment":["state-solid","transient-only"],"summary":"A polar film cycled in temperature releases surface charge into a load.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-d5a54d0ad6","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/d5a54d0ad6"},{"id":"pathway:thermogalvanic-cell","name":"Thermogalvanic cell","steps":["claim:thermogalvanic-drives","claim:thermogalvanic-produces-ions","claim:ionic-current-converts-electricity"],"demonstrated_with":["transducer:thermocell"],"evidence":["source:quickenden-mua-1995","source:dupont-2017"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","environment":["env-aqueous","temp-gradient-required"],"summary":"Two identical electrodes at different temperatures in one redox electrolyte.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-33b2bcd5b2","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/33b2bcd5b2"},{"id":"pathway:thermally-regenerative-electrochemical-cycle","name":"Thermally regenerative electrochemical cycle","steps":["claim:trec-drives","claim:trec-produces-ions","claim:ionic-current-converts-electricity"],"demonstrated_with":[],"evidence":["source:lee-2014-trec"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K5","performance":{"measurements":[{"quantity":"heat-to-electricity cycle efficiency (no heat recuperation)","value":"3.7%","value_numeric":0.037,"unit":"1","metric":"conversion-efficiency","basis":"electrical energy per cycle over heat absorbed, cycled between 10 °C and 60 °C, without heat recuperation","parameters":{"T_h_K":333.15,"T_c_K":283.15},"scope":"device","conditions":"copper hexacyanoferrate cathode against a Cu/Cu²⁺ anode, a thermally regenerative electrochemical cycle charged at one temperature and discharged at the other","sources":["source:lee-2014-trec"],"year":2014},{"quantity":"heat-to-electricity cycle efficiency (50 % heat recuperation assumed)","value":"5.7%","value_numeric":0.057,"unit":"1","metric":"conversion-efficiency","basis":"the same cycle with 50 % of the rejected heat assumed recuperated into the heating step","datum_kind":"derived","parameters":{"T_h_K":333.15,"T_c_K":283.15},"scope":"model","conditions":"the same device and temperatures; the recuperation is an assumption, not a measured heat exchanger","sources":["source:lee-2014-trec"],"year":2014,"note":"the figure the abstract leads with; the atlas records it as a model datum because the 50 % recuperation is assumed"}]},"environment":["env-aqueous","temp-gradient-required"],"summary":"Charge cold, discharge warm; 5.7% efficiency between 10 and 60 °C with heat recuperation.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-2b44cdfdff","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/2b44cdfdff"},{"id":"pathway:thermomagnetic-generator","name":"Thermomagnetic generator","steps":["claim:thermomagnetic-drives","claim:thermomagnetic-produces-flux","claim:magnetic-flux-drives-induction","claim:induction-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:thermomagnetic-generator"],"evidence":["source:kishore-priya-2018","source:waske-2019"],"status":"demonstrated","regime_provides":["thermal:transition-temperature-straddled","thermal:cyclic-hot-cold-exposure"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","performance":{"measurements":[{"quantity":"electrical output power","value":"0.8 mW","value_numeric":0.0008,"unit":"W","parameters":{"T_transition_K":300,"cycle_frequency_Hz":0.8},"scope":"device","conditions":"Waske et al. 2019 supplementary information: the genus-3 (pretzel) magnetic circuit with La-Fe-Co-Si (CALORIVAC C) plates of transition temperature 300 K, the fluid circuits switched by ΔT = 30 K at the experimentally optimal cycle frequency of 0.8 Hz (cycle time 1.25 s), fluid flux 0.4 l/min; falls to 0.01 mW when the genus is reduced to 1","sources":["source:waske-2019"],"year":2019,"note":"read from the open supplementary PDF (fluid temperatures measured with four Pt1000 sensors at the plate-stack inlet); the main text's peak figures and their exact temperature pair are behind the paywall, and the 285 K / 315 K endpoints appear there only as the simulation's B–H curves, so T_h_K / T_c_K are not recorded"}]},"environment":["state-solid","temp-gradient-required"],"summary":"A gadolinium element switching between hot and cold changes the flux through a coil.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-b142ef2073","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/b142ef2073"},{"id":"pathway:thermophotovoltaic","name":"Thermophotovoltaic conversion","steps":["claim:thermal-emission-drives","claim:thermal-emission-produces-photons","claim:photons-drive-pv","claim:pv-produces-pairs","claim:pairs-convert-electricity"],"demonstrated_with":["transducer:thermophotovoltaic-cell"],"evidence":["source:lapotin-2022"],"status":"demonstrated","regime_provides":["light:above-bandgap-photon-flux"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K7","performance":{"notes":"published models predict thermophotovoltaic efficiencies above 50 % with better photon recycling (LaPotin et al. 2022 cite them) — a projection, not a thermodynamic bound, so it lives here, not in the limit field","measurements":[{"quantity":"electrical power density","value":"2.39 W/cm²","value_numeric":2.39,"unit":"W/cm²","metric":"power-density","basis":"electrical output per unit cell area at the maximum-efficiency operating point","normalization":{"kind":"area","basis":"active-device-area"},"parameters":{"T_emitter_K":2673.15},"scope":"device","conditions":"the 1.4/1.2 eV two-junction III–V cell at (41.1 ± 1) % efficiency with a 2400 °C emitter","sources":["source:lapotin-2022"],"year":2022},{"quantity":"thermophotovoltaic cell efficiency","value":"41.1 ± 1 %","value_numeric":0.411,"unit":"1","metric":"conversion-efficiency","basis":"electrical output over the net radiative heat absorbed by the cell, sub-bandgap radiation reflected back to the emitter — the emitter is the route's hot reservoir, so the net radiation it delivers to the cell is the heat the route draws from its source (the route's Q_h); the emitter's own supply losses lie outside the route's thermodynamic boundary, which is why this is the route's figure and not a stage figure (pass 45)","parameters":{"T_emitter_K":2673.15},"scope":"device","conditions":"1.4/1.2 eV two-junction III–V tandem with a highly reflective back-surface reflector, emitter at 2400 °C, power density 2.39 W cm⁻²; a 1.2/1.0 eV device reached 39.3 ± 1 %","sources":["source:lapotin-2022"],"year":2022,"note":"the cell temperature is not in the abstract, so T_c_K is not recorded and the Carnot check stays unresolved on this datum"}]},"environment":["temp-high"],"summary":"A 2400 °C emitter radiates into a tandem III–V cell with a back reflector; 40% measured.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-9962e01b70","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/9962e01b70"},{"id":"pathway:rankine-steam-plant","name":"Steam Rankine plant","steps":["claim:expansion-drives","claim:expansion-produces-motion","claim:motion-drives-generator","claim:generator-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:rankine-cycle-plant"],"evidence":["source:bejan-2016","source:shaheed-2023-al-mosyab","source:nicol-2015-ieaccc-double-reheat"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[{"kind":"recirculating-work","energy_form":"mechanical","purpose":"feedwater pump","establishes":[],"conditions":["condensed working fluid is pumped from condenser pressure to boiler pressure before heat addition; pump work is an internal cycle load and whole-cycle net efficiency includes it","Al-Mosyab Unit 3 (Shaheed, Mohammed & Radhi 2023, read in full): three main boiler feedwater pumps and three condensate pumps with a deaerator return the condensate to the 152 bar main-steam pressure; the boiler feed pump appears in the unit's exergy ledger (Table 4)"],"evidence":["source:shaheed-2023-al-mosyab"],"note":"recorded on the reviewer's pass-36 ruling; not on pathway:steam-engine (a generic spelling demonstrated by the Rankine transducer — a pathway-specificity item for a later architecture audit) and not on pathway:nuclear-steam-plant (which owes the pressure-drop provider and awaits a source review of its named architecture)"}],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","performance":{"measurements":[{"quantity":"net plant electrical efficiency","value":"47%","value_numeric":0.47,"unit":"1","metric":"conversion-efficiency","basis":"operating net electrical efficiency (electrical output to the 400 kV grid over fuel energy); fuel lower-heating-value basis; power-only (condensing) mode — an operating figure, not an annual one","parameters":{"T_turbine_inlet_K":853.15,"T_cooling_water_inlet_K":283.15},"scope":"plant","conditions":"Nordjylland unit 3, Denmark (415 MWe, commissioned 1998): once-through ultra-supercritical Benson tower boiler, double reheat, 580 °C / 580 °C / 580 °C at 29 MPa, 10 °C seawater cooling; 2005 performance in power-only mode at 100 % load — generator 411 MWe, auxiliaries 26 MWe, 385 MWe to grid, boiler efficiency 94.2 %, heat rate 7151.4 kJ/kWh on generator output; the world's most efficient pulverised-coal unit as of December 2014 per the IEA Clean Coal Centre","sources":["source:nicol-2015-ieaccc-double-reheat"],"year":2015,"note":"read in full in CCC/255 §7.2.6 and Table 4 (Poulsen & Bendixen 2006); the table's own 47.2 % (400 kV to grid) row sits beside a coal calorific value labelled gross (26 MJ/kg) while the text gives 25.2 MJ/kg LHV / 26.4 MJ/kg HHV, so the atlas records the text's explicit net-LHV statement; the second reader's Morrison 2008 IEA CCC citation (47 % LHV / 44.9 % HHV) could not be located — CCC/255 cites Morrison 2011 for the same fact; the steam temperature and cooling-water temperature are operating states, never the Carnot reservoirs"},{"quantity":"unit electrical load at the recorded operating state","value":"225 MW","value_numeric":225000000,"unit":"W","parameters":{"T_turbine_inlet_K":812.15,"T_cooling_water_inlet_K":297.15},"scope":"plant","conditions":"Al-Mosyab thermal power station, Iraq (completed 1990, four 300 MW units), Unit 3 at 225 MW load — Table 1 'general current operation condition': main steam 168 kg/s at 152 bar and 539 °C, crude-oil fuel 14.68 kg/s at NCV 10,074 kcal/kg, condenser pressure 0.1 bar, cooling-water temperature 24 °C, generator 3000 rpm; subcritical single-drum natural-circulation boiler, HP / IP / LP turbines, six closed feedwater heaters and a deaerator","sources":["source:shaheed-2023-al-mosyab"],"year":2023,"note":"the unit's readings, not the design condition (300 MW, 170 bar, 538 °C, 0.0653 bar, 23 °C cooling water); pressures stay in the conditions text — the registry has no pressure names; the operating-state temperatures never feed the Carnot bound"},{"quantity":"cycle thermal efficiency (energy balance of the readings)","value":"39.3%","value_numeric":0.393,"unit":"1","metric":"conversion-efficiency","basis":"first-law efficiency of the cycle from the authors' Engineering Equation Solver model of the Unit 3 readings (Table 4, 'cycle' row); the heat input is the heat added to the working fluid (boiler thermal efficiency 94 % in the same table), not the fuel's NCV","datum_kind":"derived","parameters":{"T_turbine_inlet_K":812.15,"T_cooling_water_inlet_K":297.15},"scope":"model","conditions":"derived from the actual 225 MW operating readings above; the same model gives second-law efficiency 34.91 % and exergy destruction 412.68 MW","sources":["source:shaheed-2023-al-mosyab"],"year":2023,"note":"Source-internal discrepancy: Table 4 reports cycle thermal efficiency 39.3%; surrounding prose reports 39.91%. The atlas records the tabulated value because Table 4 is the paper's declared energy/exergy result table; no reconciliation is supplied by the authors (Figure 2's condenser-pressure sweep gives 39.39 % at 0.06 bar falling to 37.97 % at 0.24 bar; the unit runs at 0.1 bar). Computed, not metered. Not a record figure: efficiency_record 0.47 stands"}]},"environment":["temp-gradient-required"],"summary":"Heat raises steam; the turbine turns the generator. Most of the world's thermal electricity.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-9f97be27de","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/9f97be27de"},{"id":"pathway:combustion-gas-turbine","name":"Combustion gas-turbine plant","steps":["claim:combustion-drives","claim:combustion-produces-hot-gas","claim:hot-gas-drives-expansion","claim:expansion-produces-motion","claim:motion-drives-generator","claim:generator-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:gas-turbine-generator"],"evidence":["source:bejan-2016","source:dixon-hall-2014","source:al-mhanna-2024-isccs"],"status":"commercial","regime_provides":["thermodynamic:expansion-pressure-drop"],"regime_model_provides":[],"auxiliary_requirements":[{"kind":"recirculating-work","energy_form":"mechanical","purpose":"compressor","establishes":["thermodynamic:expansion-pressure-drop"],"conditions":["turbine shaft work drives the compressor that establishes the expansion pressure ratio; cycle net work is turbine work minus compressor work","the local plant of Al Mhanna 2024: air 505.36 kg/s compressed from 0.9981 bar to 9.4 bar (isentropic efficiency 0.883) before the combustor, turbine discharge 1 bar"],"evidence":["source:dixon-hall-2014","source:al-mhanna-2024-isccs"],"note":"a feedback branch (turbine motion → compressor → pressurised inlet → combustor → turbine), not a serial step, so it is metadata here and never a route claim; whole-cycle and net efficiencies include this back-work while the enumerated route is the useful-output causal spine"}],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","performance":{"notes":"model relation, not a bound of the real pathway: the ideal air-standard Brayton cycle's thermal efficiency is 1 − r_p^((1−γ)/γ) at pressure ratio r_p, with net work the turbine work minus the compressor work; a real cycle's net efficiency depends on both and on the turbine inlet temperature the materials allow","measurements":[{"quantity":"gas-turbine work output","value":"127 MW","value_numeric":127000000,"unit":"W","parameters":{"T_turbine_inlet_K":1323.15,"T_turbine_exhaust_K":813.85},"scope":"plant","conditions":"Table 3 'local plant data' of a 678 MW combined-cycle gas-turbine station in Oman (three gas turbines, two steam turbines; one gas-turbine train modelled): gas-turbine inlet 1050 °C, exhaust 540.7 °C; Table 2 plant inputs — air 505.36 kg/s at 26.6 °C and 0.9981 bar, compressor discharge 9.4 bar, natural-gas fuel 9.2 kg/s at 22.8 bar (LHV 43,662 kJ/kg, 92.5 % methane), turbine discharge 1 bar","sources":["source:al-mhanna-2024-isccs"],"year":2024,"note":"the steam turbine of the same train delivers 61.5 MW and the table's 46.93 % is the combined cycle's efficiency — (127 + 61.5) MW over 9.2 kg/s × 43,662 kJ/kg = 401.7 MW reproduces it exactly — so it belongs to no pathway the atlas spells (the gas-turbine share alone would be 127 / 401.7 ≈ 31.6 %, a derivation, not a source figure); the paper's Aspen Plus simulation reproduces the plant within 0.43–3.77 % (126.45 MW, 1010.46 °C, 556.93 °C, 46.28 %) and is not recorded"}]},"environment":["state-gas","temp-high"],"summary":"Fuel burns, hot gas expands through the turbine, the shaft turns the alternator.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-62674bc82d","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/62674bc82d"},{"id":"pathway:otec-plant","name":"Ocean thermal energy conversion plant","steps":["claim:otec-drives","claim:otec-produces-motion","claim:motion-drives-generator","claim:generator-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":[],"evidence":["source:claude-1930","source:bejan-2016","source:lu-2024-otec-platform"],"status":"prototype","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K7","performance":{"measurements":[{"quantity":"system thermal efficiency (design point)","value":"2.63%","value_numeric":0.0263,"unit":"1","metric":"device-stage-efficiency","basis":"the organic-Rankine stage alone: net cycle work W_net = W_T − W_P (turbine work minus working-fluid pump work) over the evaporator heat Q_e — the paper's Equations 7 and 9, read again in pass 45 — before the generator the pathway ends in; it reproduces the design value (0.0263 × 1608.56 kW = 42.3 kW net, the 50.3 kW turbine less ≈ 8 kW of pump work), which the plain turbine-over-evaporator ratio did not","datum_kind":"design-point","parameters":{"T_h_K":301.15,"T_c_K":277.15},"scope":"model","conditions":"design point of a land-based 50 kW R134a organic-Rankine OTEC platform: 28 °C warm-seawater source, 4 °C cold-seawater source; Table 1 state points ≈ 24.6 °C / 645.8 kPa evaporation and ≈ 8 °C / 387.6 kPa condensation; check values warm seawater 191.49 kg/s, cold seawater 183.93 kg/s, working fluid 7.648 kg/s, turbine output 50.3 kW","sources":["source:lu-2024-otec-platform"],"year":2024,"note":"a model-scope datum: it supplies no regime to the route; the initial thermodynamic calculation gave 3.22 % and 51.08 kW before the pressure-drop check"},{"quantity":"actual system thermal efficiency","value":"2.46%","value_numeric":0.0246,"unit":"1","metric":"conversion-efficiency","basis":"as reported: the authors' actual thermal efficiency in the stable-operation phase (Figure 12). The paper defines thermal efficiency as net cycle work over evaporator heat (Equation 9) and reports 2.46 % beside the 47.4 kW maximum grid-connected power without saying which numerator the actual figure uses — a route figure if the grid-connected power, an organic-Rankine-stage figure if the net cycle work; the boundary is unresolved (pass 45)","scope":"laboratory","conditions":"the same platform run on land with a heat-pump unit simulating the seawater; the conclusion states the heat source was held at 24–28 °C and the cold source at 4–8 °C, while Figure 11 shows the warm water at ≈ 27.5–30.5 °C and the cold water at ≈ 4.5–7 °C over the 6000 s run with the flows stepped from ≈ 530 to ≈ 740 m³/h; the turbine supply valve fully open from ≈ 3900 s","sources":["source:lu-2024-otec-platform"],"year":2024,"note":"no T_h_K / T_c_K: the paper prints no temperature pair for the operating point of the reported efficiency, and the run's temperatures are read only from Figure 11 (≈ 30 °C / ≈ 6.3 °C at the moment of peak power) — a graphical reading, not recorded as parameters; 28 °C / 4 °C is the design point, not this datum's"},{"quantity":"maximum grid-connected electrical power","value":"47.4 kW","value_numeric":47400,"unit":"W","scope":"laboratory","conditions":"the same run, at the end of the stable-operation phase (≈ 5400 s), at the highest warm-water temperature and flows of the run","sources":["source:lu-2024-otec-platform"],"year":2024,"note":"47.4 kW in the conclusions, 47.5 kW in the abstract; the design output is 50 kW"}]},"environment":["state-liquid","temp-gradient-required"],"summary":"Warm surface water evaporates a working fluid condensed by deep cold water; 100 kW-class plants have run.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-e238ea3af4","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/e238ea3af4"},{"id":"pathway:radiative-cooling-teg","name":"Night-time radiative-cooling thermoelectric generator","steps":["claim:sky-drives-radiative-cooling","claim:radiative-cooling-produces-gradient","claim:seebeck-drives","claim:seebeck-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:radiative-cooler-teg"],"evidence":["source:raman-2019-night"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K4","performance":{"measurements":[{"quantity":"electrical power density","value":"25 mW/m²","value_numeric":0.025,"unit":"W/m²","metric":"power-density","basis":"maximum-power-point thermoelectric electrical output (nearly 0.8 mW; J_sc 44 mA, V_oc 79 mV) normalised to the area of the 200 mm radiative-cooler disk","normalization":{"kind":"area","basis":"radiative-cooler-area"},"scope":"device","conditions":"clear-night rooftop experiment at Stanford, CA, late December 2017, dew point −1 to −3 °C, device 1 m above roof level; a 200 mm aluminium disk painted black (ε ≈ 0.95) as the sky-facing emitter on the cold side of a Marlow TG12-4 module (ZT = 0.71) inside a polystyrene enclosure with a 12.5 µm polyethylene wind cover; the hot side coupled to a finned 200 mm aluminium disk in ambient air","sources":["source:raman-2019-night"],"year":2019,"note":"read on the Cell Press page in the owner's Chrome (the article carries the PII S2542-4351(19)30412-X); the paper's 'pathways to improving performance … to 0.5 W/m²' is a projection with stated component improvements and is not recorded as a physical datum"}]},"environment":["temp-gradient-required"],"summary":"A sky-facing emitter cools the cold side of a thermoelectric module below ambient at night.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-cf54e1e763","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/cf54e1e763"},{"id":"pathway:piezoelectric-vibration-harvester","name":"Piezoelectric vibration harvester","steps":["claim:vibration-drives-resonance","claim:resonance-produces-stress","claim:piezo-drives","claim:piezo-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":["transducer:piezoelectric-harvester"],"evidence":["source:anton-sodano-2007","source:erturk-inman-2011","source:roundy-2003"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","environment":["state-solid"],"summary":"A tuned cantilever bends a piezoelectric layer; charge flows each half cycle.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-a61d9ac2dc","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/a61d9ac2dc"},{"id":"pathway:triboelectric-nanogenerator","name":"Triboelectric nanogenerator","steps":["claim:vibration-drives-tribo","claim:tribo-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":["transducer:triboelectric-nanogenerator"],"evidence":["source:fan-tian-wang-2012"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","environment":["state-solid","medium-dielectric"],"summary":"Two polymer films contact and separate; induced charge cycles through the load.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-3bba97cb6e","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/3bba97cb6e"},{"id":"pathway:electrostatic-vibration-harvester","name":"Electrostatic (electret) vibration harvester","steps":["claim:electrostatic-drives","claim:electrostatic-produces","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:electrostatic-harvester"],"evidence":["source:roundy-2003"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","environment":["state-solid","field-electric-required"],"summary":"A MEMS variable capacitor with an electret bias.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-39924907ce","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/39924907ce"},{"id":"pathway:electromagnetic-vibration-harvester","name":"Electromagnetic vibration harvester","steps":["claim:vibration-drives-resonance","claim:resonance-produces-motion","claim:motion-drives-induction","claim:induction-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:electromagnetic-vibration-harvester"],"evidence":["source:beeby-2007"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","performance":{"measurements":[{"quantity":"electrical power into a resistive load","value":"46 µW","value_numeric":0.000046,"unit":"W","metric":"power","basis":"power delivered into a 4 kΩ resistive load at the generator's resonance","scope":"device","conditions":"four magnets on an etched cantilever with a 2300-turn wound coil, component volume 0.1 cm³ and practical volume 0.15 cm³, driven at 0.59 m/s² acceleration at its 52 Hz resonance; 428 mV rms; 30 % of the power supplied from the environment delivered to the load","sources":["source:beeby-2007"],"year":2007,"note":"46 µW over the 0.15 cm³ practical volume is ≈ 307 µW/cm³ — a derivation from two abstract figures, not the paper's stated density"}]},"environment":["state-solid"],"summary":"A sprung magnet moves through a coil.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-9003e4a59f","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/9003e4a59f"},{"id":"pathway:magnetostrictive-harvester","name":"Magnetostrictive vibration harvester","steps":["claim:vibration-drives-resonance","claim:resonance-produces-stress","claim:villari-drives","claim:villari-produces-flux","claim:magnetic-flux-drives-induction","claim:induction-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:magnetostrictive-harvester"],"evidence":["source:wang-yuan-2008"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","environment":["state-solid","medium-ferromagnet"],"summary":"Cyclic stress changes the magnetisation of a Galfenol rod inside a pickup coil.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-2986527b85","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/2986527b85"},{"id":"pathway:magnetoelectric-field-harvester","name":"Magnetoelectric stray-field harvester","steps":["claim:magnetoelectric-drives","claim:magnetoelectric-produces","claim:surface-charge-converts-electricity"],"demonstrated_with":["transducer:magnetoelectric-composite"],"evidence":["source:nan-2008"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","environment":["state-solid"],"summary":"An AC field strains the magnetostrictive layer, which stresses the bonded piezoelectric layer.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-16ea21f14d","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/16ea21f14d"},{"id":"pathway:wind-turbine","name":"Wind turbine","steps":["claim:flow-drives-lift","claim:lift-produces-motion","claim:motion-drives-generator","claim:generator-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:wind-turbine"],"evidence":["source:betz-1920","source:dixon-hall-2014"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","performance":{"measurements":[{"quantity":"peak rotor power coefficient","value":"≈ 0.45","value_numeric":0.45,"unit":"1","metric":"power-coefficient","basis":"rotor power coefficient on the free-stream kinetic power through the swept area","datum_kind":"derived","scope":"field","conditions":"Southwest Windpower Storm pre-prototype, a three-blade downwind variable-speed stall-regulated turbine rated 1.8 kW; deduced from field-test measured electrical power and dynamometer-measured alternator efficiency; a broad, flat curve near C_p ≈ 0.43 over a 4 m/s wind-speed range; preliminary, with definitive NWTC tests under way at the time","sources":["source:migliore-2005-nrel-cp-500-38157"],"year":2005,"note":"the atlas had carried 0.52 as an efficiency_record until pass 39 — the wrong quantity for a pathway that ends in electrical work; this is the rotor's coefficient, comparable with the Betz limit and nothing else"}]},"environment":["flow-required"],"summary":"Blade lift turns the rotor; the rotor turns the generator.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-5b96b456b1","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/5b96b456b1"},{"id":"pathway:hydroelectric-plant","name":"Hydroelectric plant","steps":["claim:gravity-drives-descent","claim:descent-produces-pressure","claim:hydraulic-drives-lift","claim:lift-produces-motion","claim:motion-drives-generator","claim:generator-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:hydro-turbine"],"evidence":["source:dixon-hall-2014"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","performance":{"notes":"No thermodynamic ceiling below unity applies to a head → shaft → electrical conversion, so no bound is recorded; the losses are hydraulic and electrical.","measurements":[{"quantity":"water-to-wire plant efficiency","value":"60%","value_numeric":0.6,"unit":"1","metric":"conversion-efficiency","basis":"electrical output over the hydraulic power of the flow through the plant's gross head (water-to-wire), as the report states it; the report gives no formula and does not state the grid-side electrical boundary","datum_kind":"derived","scope":"plant","conditions":"Natel SLH100 hydroEngine (linearly moving foils rather than a rotor) at the Monroe Drop on the North Unit Irrigation District main canal, Madras, Oregon; 250 kW nameplate; gross head 4.1–5.1 m; maximum flow 331 cfs; maximum observed plant power 267 kW; commissioned September 2015","sources":["source:schneider-2017-monroe-hydro-doe"],"year":2017},{"quantity":"hydraulic efficiency of the hydroEngine","value":"73%","value_numeric":0.73,"unit":"1","metric":"device-stage-efficiency","basis":"the turbine stage alone: mechanical power delivered by the hydroEngine relative to the hydraulic power at its inlet, as the report states it (no formula given) — a subsystem figure, not the pathway's water-to-wire efficiency","datum_kind":"derived","scope":"plant","conditions":"the same installation at its 267 kW maximum","sources":["source:schneider-2017-monroe-hydro-doe"],"year":2017}]},"environment":["state-liquid"],"summary":"Water falls through the penstock, spins the turbine, turns the generator.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-ceb6911dc3","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/ceb6911dc3"},{"id":"pathway:reverse-electrodialysis-plant","name":"Reverse electrodialysis plant","steps":["claim:salinity-drives-red","claim:red-produces-ions","claim:ionic-current-converts-electricity"],"demonstrated_with":["transducer:reverse-electrodialysis-stack"],"evidence":["source:post-2007","source:logan-elimelech-2012"],"status":"prototype","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K7","environment":["env-aqueous","medium-membrane"],"summary":"Ion-selective membranes turn the mixing of river and sea water into a stack voltage.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-56307771c5","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/56307771c5"},{"id":"pathway:pressure-retarded-osmosis-plant","name":"Pressure-retarded osmosis plant","steps":["claim:salinity-drives-pro","claim:pro-produces-pressure","claim:hydraulic-drives-lift","claim:lift-produces-motion","claim:motion-drives-generator","claim:generator-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:pressure-retarded-osmosis-plant"],"evidence":["source:loeb-1975","source:logan-elimelech-2012"],"status":"prototype","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K7","environment":["env-aqueous","medium-membrane"],"summary":"Fresh water permeates into pressurised seawater; the extra volume drives a turbine.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-6cf5ab09ab","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/6cf5ab09ab"},{"id":"pathway:photovoltaic-module","name":"Photovoltaic module","steps":["claim:pv-drives","claim:pv-produces-pairs","claim:pairs-convert-electricity"],"demonstrated_with":["transducer:photovoltaic-cell"],"evidence":["source:chapin-1954","source:shockley-queisser-1961","source:green-2024-tables"],"status":"commercial","regime_provides":["light:above-bandgap-photon-flux"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","performance":{"measurements":[{"quantity":"confirmed module efficiency (crystalline silicon)","value":"24.7 ± 0.3 %","value_numeric":0.247,"unit":"1","metric":"conversion-efficiency","basis":"designated-area module efficiency under the global AM1.5 spectrum (1000 W/m²) at a cell temperature of 25 °C, independently confirmed","scope":"module","conditions":"Maxeon 112-cell crystalline-silicon module, 17,806 cm² designated area, V_oc 83.04 V, I_sc 6.384 A, fill factor 82.9 %, NREL 4/23 — Table 4 of Green et al. 2024 (Version 63); the multijunction module record in the same table is 32.65 ± 0.7 % (Sharp InGaP/GaAs/InGaAs, 965 cm²)","sources":["source:green-2024-tables"],"year":2024}]},"environment":["state-solid","illumination-required"],"summary":"Photons make electron–hole pairs; the junction separates them.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-0a44a53e81","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/0a44a53e81"},{"id":"pathway:solar-thermal-rankine","name":"Concentrating solar-thermal plant","steps":["claim:photothermal-drives","claim:photothermal-produces-gradient","claim:expansion-drives","claim:expansion-produces-motion","claim:motion-drives-generator","claim:generator-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:solar-thermal-collector","transducer:rankine-cycle-plant"],"evidence":["source:bejan-2016"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","environment":["illumination-required","temp-gradient-required"],"summary":"Mirrors heat a receiver; the receiver drives a steam cycle.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-bc0f8f89db","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/bc0f8f89db"},{"id":"pathway:photoelectrochemical-water-splitting","name":"Photoelectrochemical water splitting","steps":["claim:pec-drives","claim:pec-converts-fuel"],"demonstrated_with":["transducer:photoelectrochemical-cell"],"evidence":["source:fujishima-honda-1972","source:cheng-2018-pec-19-percent"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K5","performance":{"measurements":[]},"environment":["env-aqueous","illumination-required"],"summary":"Photogenerated carriers split water at a semiconductor–electrolyte interface.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-65bd8cfaf8","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/65bd8cfaf8"},{"id":"pathway:tandem-pec-gainp-gainas-1p78-1p26ev","name":"Tandem PEC photocathode, GaInP/GaInAs 1.78 / 1.26 eV (Cheng 2018)","steps":["claim:pec-drives","claim:pec-converts-fuel"],"demonstrated_with":["transducer:photoelectrochemical-cell"],"evidence":["source:cheng-2018-pec-19-percent"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"variant_of":"pathway:photoelectrochemical-water-splitting","bounds":[{"constraint":"constraint:pec-tandem-gainp-gainas-1p78-1p26ev-limit","evidence":["source:cheng-2018-pec-19-percent","source:fountaine-2016-pec-limits"],"conditions":["the limit is computed for exactly this gap pair, 1.78 eV / 1.26 eV, in the SQwater framework; the global dual-junction maximum (40.0 % at 0.52 / 1.40 eV) reaches the same route through the phenomenon"],"note":"the first architecture-specific bound in the atlas: it lives here and never on the generic photoelectrochemical route"}],"knowledge_level":"K5","performance":{"measurements":[{"quantity":"solar-to-hydrogen efficiency (acidic electrolyte)","value":"19.3%","value_numeric":0.193,"unit":"1","metric":"conversion-efficiency","basis":"PEC water splitting, dual-junction absorber, AM1.5G","datum_kind":"measured","scope":"device","conditions":"hydrogen free-energy output over incident simulated AM 1.5G solar power, unassisted; monolithic Ga₀.₄₁In₀.₅₉P / Ga₀.₈₉In₀.₁₁As tandem photocathode (1.78 / 1.26 eV) with a crystalline TiO₂ interlayer and Rh nanoparticle catalyst, acidic perchlorate electrolyte, the initial efficiency; the authors place it at 0.85 of the 22.8 % theoretical limit for this gap combination","sources":["source:cheng-2018-pec-19-percent"],"year":2018},{"quantity":"solar-to-hydrogen efficiency (neutral electrolyte)","value":"18.5%","value_numeric":0.185,"unit":"1","metric":"conversion-efficiency","basis":"PEC water splitting, dual-junction absorber, AM1.5G","datum_kind":"measured","scope":"device","conditions":"the same device in a buffered solution at pH 7, unassisted, under simulated AM 1.5G","sources":["source:cheng-2018-pec-19-percent"],"year":2018}]},"environment":["env-aqueous","illumination-required"],"summary":"Cheng et al.'s monolithic tandem photocathode — a GaInP/GaInAs dual junction of 1.78 and 1.26 eV, a TiO₂ interlayer and Rh catalyst — splits water unassisted at 19.3 % solar-to-hydrogen in acid, 0.85 of the theoretical limit for its own gap pair. A variant of the generic photoelectrochemical pathway on the same route, holding the data and the bound that belong to this architecture alone.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 46 (Cheng 2018 full text read on arXiv 1706.01493; Fountaine 2016 read)"},"route_id":"p-65bd8cfaf8","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/pathway/tandem-pec-gainp-gainas-1p78-1p26ev"},{"id":"pathway:betavoltaic-battery","name":"Betavoltaic battery","steps":["claim:binding-drives-decay","claim:decay-produces-particles","claim:particles-drive-betavoltaic","claim:betavoltaic-produces-pairs","claim:pairs-convert-electricity"],"demonstrated_with":["transducer:betavoltaic-cell"],"evidence":["source:rappaport-1954","source:prelas-2014"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","performance":{"measurements":[{"quantity":"energy conversion efficiency of a ¹⁴C perovskite betavoltaic cell","value":"10.79%","value_numeric":0.1079,"unit":"1","metric":"conversion-efficiency","basis":"battery output power over the isotope source's total decay power: J_sc × V_oc × FF / (E_avg × e × A) with A = 4.5 µCi per 1.0 cm² of active area and E_avg = 49.4 keV per decay (SI Equation 1: 0.142 nW / 1.316 nW); the nominal activity, no self-absorption correction","datum_kind":"derived","scope":"device","conditions":"FTO/SnO₂/MACl-FAPbI₃/Spiro-MeOTAD/¹⁴C-nanoparticle/CQD/FTO cell; J_sc 10.60 nA cm⁻², V_oc 76.92 mV, FF 17.41 %; I–V by sourcemeter over −0.1 to +0.8 V; over 15 h of continuous operation","sources":["source:kim-2026-c14-perovskite-betavoltaic"],"year":2026},{"quantity":"total energy conversion efficiency of the 4H-SiC betavoltaics under a ⁶³Ni source","value":"2.34–2.56%","value_range":[0.0234,0.0256],"unit":"1","metric":"conversion-efficiency","basis":"battery output power over the isotope source power A·E_ave·q (Equation 1); η = η_s × η_d, the source efficiency η_s ≈ 35 % for 500 nm ⁶³Ni with single-side emission; an aggregate range over the measured devices (Table 4, 'This work (SiC)') — the paper gives no per-device tuple, so no scalar is recorded and the upper end is never a record","datum_kind":"derived","scope":"device","conditions":"4H-SiC PIN devices under a ⁶³Ni source of 1 × 3 cm² active area and 15 mCi total activity; V_oc 1.22–1.41 V, FF 0.81–0.89","sources":["source:zhang-2025-sic-betavoltaic"],"year":2025},{"quantity":"semiconductor device efficiency η_d of the best 4H-SiC device under ⁶³Ni","value":"7.31%","value_numeric":0.0731,"unit":"1","metric":"device-stage-efficiency","basis":"the semiconductor stage alone: output power relative to the beta power leaving the source (η_d = η / η_s), excluding the source's self-absorption — never the battery's efficiency against the isotope's decay power","datum_kind":"measured","scope":"device","conditions":"I_sc 2.91 nA, V_oc 1.41 V, FF 0.81 under the 15 mCi ⁶³Ni source (Table 3); 14.88 % for the same device under an electron beam","sources":["source:zhang-2025-sic-betavoltaic"],"year":2025}]},"environment":["state-solid","radioisotope-required"],"summary":"Beta particles make carrier pairs in a junction for as long as the isotope lasts.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-be2ddc1ccd","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/be2ddc1ccd"},{"id":"pathway:radioisotope-thermoelectric-generator","name":"Radioisotope thermoelectric generator","steps":["claim:binding-drives-decay","claim:decay-produces-alpha","claim:alpha-drives-heating","claim:heating-produces-gradient","claim:seebeck-drives","claim:seebeck-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:radioisotope-thermoelectric-generator"],"evidence":["source:prelas-2014","source:rowe-2006"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","environment":["state-solid","radioisotope-required"],"summary":"Decay heat across thermoelectric couples; powers deep-space probes.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-852d67c261","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/852d67c261"},{"id":"pathway:spin-seebeck-thermopile","name":"Spin Seebeck thermopile","steps":["claim:sse-drives","claim:sse-produces-spin-current","claim:spin-current-drives-ishe","claim:ishe-produces","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:spin-seebeck-device"],"evidence":["source:uchida-2008","source:uchida-2010-insulator","source:bauer-2012"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K4","environment":["state-solid","temp-gradient-required"],"summary":"Heat drives magnons in YIG; the Pt strip converts the pumped spin current to a voltage.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-1b23e63cca","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/1b23e63cca"},{"id":"pathway:rectenna-microwave","name":"Microwave rectenna","steps":["claim:radiation-drives-antenna","claim:antenna-couples-rectification","claim:rectification-produces","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:rectenna"],"evidence":["source:brown-1984"],"status":"prototype","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K7","performance":{"notes":"No thermodynamic ceiling below unity applies to rectifying a coherent microwave beam (the Landsberg limit belongs to thermal radiation), so no bound is recorded. Do not compare a single element's RF-to-DC efficiency with a large array's capture-plus-rectification efficiency (over 82 % at Goldstone) or with end-to-end DC-to-DC beaming efficiency (54 % certified in March 1975).","measurements":[{"quantity":"rectenna element RF-to-DC conversion efficiency","value":"90.5 ± 0.5 %","value_numeric":0.905,"unit":"1","metric":"conversion-efficiency","basis":"DC power delivered to the load over microwave power input to a single rectenna element, at 8 W input, 2450 MHz","scope":"device","conditions":"the improved rectenna element of the NASA-Lewis receiving-terminal study (higher-impedance microwave circuit, higher DC load resistance, improved diodes); 79.5 ± 0.5 % at 50 mW and 45 % at 1 mW input","sources":["source:brown-1977-nasa-cr-135194"],"year":1977,"note":"the atlas had carried 0.906, the figure Brown's later reviews quote; the contractor report read in full gives 90.5 ± 0.5 % at the 8 W element level"}]},"environment":["medium-conductor"],"summary":"Brown's 1977 2.45 GHz rectenna element reached 90.5 ± 0.5 % RF-to-DC conversion at 8 W input; the Goldstone array converted over 82 % of the impinging microwave power at the rectenna boundary.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-0c86a0ef7d","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/0c86a0ef7d"},{"id":"pathway:hydrovoltaic-generator","name":"Hydrovoltaic generator","steps":["claim:humidity-drives-evaporation","claim:evaporation-produces-capillary","claim:capillary-drives-hydrovoltaic","claim:hydrovoltaic-produces-ions","claim:ionic-current-converts-electricity"],"demonstrated_with":["transducer:hydrovoltaic-generator"],"evidence":["source:xue-2017-hydrovoltaic"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K4","environment":["env-aqueous","humidity-required"],"summary":"Evaporation pulls water through a carbon film and streams ions with it.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-129d18e6c2","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/129d18e6c2"},{"id":"pathway:droplet-electricity-generator","name":"Droplet-based electricity generator","steps":["claim:gravity-drives-droplet","claim:droplet-produces-charge","claim:surface-charge-converts-electricity"],"demonstrated_with":["transducer:droplet-electricity-generator"],"evidence":["source:xu-2020-droplet"],"status":"demonstrated","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K4","performance":{"measurements":[{"quantity":"peak output power density (instantaneous)","value":"50.1 W/m²","value_numeric":50.1,"unit":"W/m²","metric":"power-density","basis":"instantaneous peak output power per unit device area at the optimal load; a per-impact peak, not a time-averaged density","normalization":{"kind":"area","basis":"active-device-area"},"scope":"device","conditions":"PTFE film on an ITO substrate with an aluminium electrode; impinging water droplets bridge the components into a closed loop; load resistance 332.0 kΩ (in a sweep from 1 kΩ to 100 MΩ the output current fell from 250.0 µA to 2.0 µA)","sources":["source:xu-2020-droplet"],"year":2020}]},"environment":["state-liquid"],"summary":"A falling droplet bridges a charged PTFE surface to an electrode and discharges it through the load.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-4f3e33ba55","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/4f3e33ba55"},{"id":"pathway:fuel-cell","name":"Hydrogen fuel cell","steps":["claim:fuel-cell-drives","claim:fuel-cell-produces-ions","claim:ionic-current-converts-electricity"],"demonstrated_with":["transducer:fuel-cell"],"evidence":["source:grove-1839","source:bard-faulkner-2001"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","environment":["medium-membrane"],"summary":"Hydrogen is oxidised at the anode, oxygen reduced at the cathode; electrons go round the load.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-05437f53ac","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/05437f53ac"},{"id":"pathway:galvanic-battery","name":"Galvanic battery discharge","steps":["claim:galvanic-drives","claim:galvanic-produces-ions","claim:ionic-current-converts-electricity"],"demonstrated_with":["transducer:galvanic-cell"],"evidence":["source:bard-faulkner-2001"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","environment":["env-aqueous"],"summary":"Stored reaction free energy delivered as current.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-0a0e9825e4","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/0a0e9825e4"},{"id":"pathway:mhd-generator","name":"Combustion MHD generator","steps":["claim:combustion-drives","claim:combustion-produces-hot-gas","claim:hot-gas-drives-gas-dynamic-expansion","claim:gas-dynamic-expansion-produces-flow","claim:flow-drives-mhd","claim:mhd-produces","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:mhd-generator"],"evidence":["source:rosa-1961-mhd","source:smith-1979-nasa-tm-79135"],"status":"prototype","regime_provides":["thermodynamic:expansion-pressure-drop"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[{"token":"thermodynamic:expansion-pressure-drop","kind":"implementation-process","component":"combustor / nozzle / generator inlet","explanation":"the pressurised seeded combustion products expand through the nozzle to the generator inlet; Smith 1979 reports the nozzle designed for Mach 2 and Mach 2 flow entering the MHD duct","evidence":["source:smith-1979-nasa-tm-79135"]}],"bounds":[],"knowledge_level":"K7","environment":["state-plasma","temp-high","field-magnetic-required"],"summary":"Seeded combustion products expand through the combustor's nozzle into a directed supersonic stream that crosses a magnet; electrodes collect the transverse current. NASA Lewis ran cesium-seeded H₂–O₂ combustion products at Mach 2 into a diverging duct of 42 electrodes in a 5 T cryomagnet — the nozzle, not a separate input, makes the flow.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-e5263f3453","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/e5263f3453"},{"id":"pathway:amtec","name":"AMTEC cell","steps":["claim:amtec-drives","claim:amtec-produces-ions","claim:ionic-current-converts-electricity"],"demonstrated_with":["transducer:amtec-cell"],"evidence":["source:cole-1983-amtec"],"status":"prototype","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K6","environment":["temp-high","state-liquid"],"summary":"Sodium ions cross a solid electrolyte; electrons take the external circuit.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-3613fe5992","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/3613fe5992"},{"id":"pathway:nuclear-steam-plant","name":"Nuclear fission steam plant","steps":["claim:binding-drives-fission","claim:fission-produces-gradient","claim:expansion-drives","claim:expansion-produces-motion","claim:motion-drives-generator","claim:generator-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:nuclear-reactor-plant"],"evidence":["source:bejan-2016","source:nrc-pressurized-water-reactors","source:nrc-boiling-water-reactors"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","environment":["temp-high"],"summary":"Fission heat establishes a thermal disequilibrium that a steam Rankine cycle converts to shaft work and electricity. The generic pathway abstracts the whole heat-engine cycle; whether the reactor coolant boils in the vessel (a BWR) or a steam generator makes the secondary steam (a PWR) is a topology the system layer will carry, never this linear route.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 38 (re-spelled on the second reader's finding; the NRC's BWR and PWR descriptions read; no feed-pump auxiliary until the named implementation is source-reviewed)"},"route_id":"p-927c9d0147","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/927c9d0147"},{"id":"pathway:photosynthesis","name":"Photosynthesis","steps":["claim:photosynthesis-drives","claim:photosynthesis-produces-carbon","claim:reduced-carbon-converts-fuel"],"demonstrated_with":[],"evidence":["source:blankenship-2011"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","environment":["env-aqueous","illumination-required"],"summary":"Light-driven charge separation stores solar energy in sugars; the basis of every fossil fuel.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-6c50dd79d5","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/6c50dd79d5"},{"id":"pathway:magnetocaloric-refrigeration","name":"Magnetocaloric refrigeration","steps":["claim:magnetocaloric-drives","claim:magnetocaloric-converts-cooling"],"demonstrated_with":["transducer:magnetocaloric-refrigerator"],"evidence":["source:pecharsky-gschneidner-1997"],"status":"prototype","regime_provides":["field:magnetic-field-cycling"],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K7","performance":{"notes":"COP comparable to vapour-compression in prototypes; not a power path — magnetic work in, cooling out","measurements":[]},"environment":["state-solid","field-magnetic-required"],"summary":"A regenerator of Gd cycled through a permanent-magnet field pumps heat.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-f4aba51c61","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/f4aba51c61"},{"id":"pathway:peltier-cooler","name":"Peltier cooler","steps":["claim:peltier-drives","claim:peltier-converts-cooling"],"demonstrated_with":[],"evidence":["source:ioffe-1957","source:goldsmid-2016"],"status":"commercial","regime_provides":[],"regime_model_provides":[],"auxiliary_requirements":[],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","performance":{"notes":"COP ≈ 0.5–1 for small ΔT; electrical work in, cooling out","measurements":[]},"environment":["state-solid"],"summary":"Current through a thermoelectric junction pumps heat from the cold side.","review":{"canonical":true,"last_reviewed":null},"route_id":"p-40987a482c","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/40987a482c"},{"id":"pathway:boiling-water-reactor-direct-steam-plant","name":"Boiling-water reactor direct-steam plant","steps":["claim:binding-drives-fission","claim:fission-produces-hot-gas","claim:hot-gas-drives-expansion","claim:expansion-produces-motion","claim:motion-drives-generator","claim:generator-produces-carriers","claim:charge-carriers-convert-electricity"],"demonstrated_with":["transducer:boiling-water-reactor-plant"],"evidence":["source:nrc-boiling-water-reactors"],"status":"commercial","regime_provides":["thermodynamic:expansion-pressure-drop"],"regime_model_provides":[],"auxiliary_requirements":[{"kind":"external-input","energy_form":"electrical","purpose":"condensate / feedwater pumping and cycle-pressure restoration","establishes":["thermodynamic:expansion-pressure-drop"],"conditions":["turbine exhaust is condensed and pumped back to the reactor vessel; reactor-vessel steam is delivered to a lower-pressure turbine / condenser side","the NRC's generic description: the resulting water is pumped out of the condenser with a series of pumps, reheated, and pumped back to the reactor vessel; the core is cooled by water circulated using electrically powered pumps"],"evidence":["source:nrc-boiling-water-reactors"],"note":"spelled as an external electrical input, not recirculating work, because the generic description does not say whether a given unit's main feedwater pumps are turbine-driven or motor-driven — a named plant would settle it (the second reader's finding 7)"}],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","environment":["temp-high"],"summary":"The reactor coolant itself boils in the vessel and its steam drives the main turbine-generator — the direct-cycle topology, distinct from the generic nuclear steam plant (fission establishes a temperature gradient a heat-engine cycle converts) and from the pressurised-water reactor, whose steam generator belongs to the system layer.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 38 (the second reader's finding 2: the BWR recorded on the direct-steam route p-dc7d860e03; the NRC description read in full)"},"route_id":"p-dc7d860e03","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/dc7d860e03"},{"id":"pathway:pwr-primary-heat-delivery","name":"PWR primary heat delivery","steps":["claim:binding-drives-fission","claim:fission-produces-gradient","claim:temperature-drives-advective-heat-transport","claim:advective-heat-transport-produces-heat-flow","claim:heat-flow-converts-useful-heat"],"demonstrated_with":["transducer:nuclear-reactor-plant"],"evidence":["source:nrc-pressurized-water-reactors"],"status":"commercial","regime_provides":["flow:bulk-fluid-motion"],"regime_model_provides":[],"auxiliary_requirements":[{"kind":"external-input","energy_form":"electrical","purpose":"reactor coolant pumps","establishes":["flow:bulk-fluid-motion"],"conditions":["electrically powered reactor coolant pumps circulate the pressurised primary water through the core and the steam generator; the loop's heat transport is forced, not buoyant"],"evidence":["source:nrc-pressurized-water-reactors"],"note":null}],"regime_establishments":[],"bounds":[],"knowledge_level":"K8","environment":["temp-high","state-liquid"],"summary":"Fission heats pressurised primary water that reactor coolant pumps circulate to the steam generator, where its heat is delivered across the tube walls to the secondary circuit — thermal energy delivered at a useful temperature, consumed inside the PWR system rather than exported.","review":{"canonical":true,"last_reviewed":"2026-09-21","reviewer":"loop-3 pass 40 (the second reader's spelling with advective transport, not conduction; the NRC's PWR description read in full)"},"route_id":"p-7cf62d4e9b","canonical_url":"https://physical-transformation-atlas.wldud5192.workers.dev/path/7cf62d4e9b"}]}