Ocean thermal energy conversion plant

Matrix context

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

D.01 × C.08 · Temperature gradient × Heat engine (thermomechanical)family: Heat engine (thermomechanical)D.01 × C.14 · Temperature gradient × Electromagnetic inductionfamily: Electromagnetic induction

Measured or reported performance

1. system thermal efficiency (design point)2.63%model2024
   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 — 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
   refs [7]
2. actual system thermal efficiency2.46%laboratory2024
   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 — 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
   refs [7]
3. maximum grid-connected electrical power47.4 kWlaboratory2024
   the same run, at the end of the stable-operation phase (≈ 5400 s), at the highest warm-water temperature and flows of the run — 47.4 kW in the conclusions, 47.5 kW in the abstract; the design output is 50 kW
   refs [7]

best recorded efficiency (derived)

2.5% — actual system thermal efficiency, laboratory, 2024; derived from the structured data above, not a stored number

Typed bounds on this route

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

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

Steps

1. 01
   Temperature gradient —drives→ Ocean thermal energy conversiondemonstratedclaim record

   thermal → mechanical · loss to thermal

   • a ≈ 20 K difference between warm surface water and cold water from ~1000 m depth

   liquid · temperature gradient required

   refs [1] [2]
2. 02
   Ocean thermal energy conversion —produces→ Mechanical motiondemonstratedclaim record

   mechanical → mechanical

   refs [1]
3. 03
   Mechanical motion —drives→ Rotating-machine generator actionestablishedclaim record

   mechanical → electrical · loss to thermal

   • a shaft turning a rotor inside a stator, or a magnet moved past a coil

   conductor required · magnetic field required

   refs [3] [4]
4. 04
   Rotating-machine generator action —produces→ Charge carriersestablishedclaim record

   electrical → electrical · loss to thermal

   refs [3] [5]
5. 05
   Charge carriers —converts into→ Electrical workestablishedclaim record

   electrical → electrical · loss to thermal

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

   refs [6]

Evidence for the complete composition · 3

1. [1]
   G. Claude. Power from the tropical seas (1930)

   Mechanical Engineering 52, 1039–1044 · paper, no DOI · record
2. [2]
   A. Bejan. Advanced Engineering Thermodynamics (4th ed.) (2016)

   Wiley · doi:10.1002/9781119245964 · crossref ✓ 2026-09-19 · record
3. [7]
   B. Lu et al.. Design and Experimental Study of 50 kW Ocean Thermal Energy Conversion Test Platform Based on Organic Rankine Cycle (2024)

   Journal of Marine Science and Engineering 12, 463 · doi:10.3390/jmse12030463 · record

Evidence for the constituent relations · 6

1. [1]
   G. Claude. Power from the tropical seas (1930)

   Mechanical Engineering 52, 1039–1044 · paper, no DOI · record
2. [2]
   A. Bejan. Advanced Engineering Thermodynamics (4th ed.) (2016)

   Wiley · doi:10.1002/9781119245964 · crossref ✓ 2026-09-19 · record
3. [3]
   M. Faraday. Experimental researches in electricity (1832)

   Philosophical Transactions of the Royal Society 122, 125–162 · doi:10.1098/rstl.1832.0006 · crossref ✓ 2026-09-19 · record
4. [4]
   S. L. Dixon, C. A. Hall. Fluid Mechanics and Thermodynamics of Turbomachinery (7th ed.) (2014)

   Butterworth-Heinemann · doi:10.1016/C2011-0-05059-7 · crossref ✓ 2026-09-19 · record
5. [5]
   L. D. Landau, E. M. Lifshitz, L. P. Pitaevskii. Electrodynamics of Continuous Media (Course of Theoretical Physics, Vol. 8, 2nd ed.) (1984)

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

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