Physics / mechanism
Thermoelectrics convert a temperature gradient directly into electrical voltage (Seebeck effect) or drive heat flow using electrical current (Peltier effect). The figure of merit ZT = S²σT/κ governs efficiency, where S is the Seebeck coefficient, σ electrical conductivity, and κ thermal conductivity. Commercial bismuth telluride (Bi₂Te₃) modules sit at ZT ≈ 0.8–1.0, yielding ~5–8% conversion efficiency at ΔT ~200 K. Research materials—half-Heuslers, skutterudites, PbTe alloys, GeTe—push ZT to 1.5–2.5 in lab conditions. Nanostructuring and phonon engineering (grain boundary scattering, rattler atoms) are the dominant levers to suppress κ without degrading σ. Solid-state, no moving parts, long MTBF.
Competitive landscape
Competing cooling approaches: vapour-compression refrigeration (COP 2–4×, but mechanically complex), heat pipes (passive, no conversion), and phase-change materials (latent heat storage, not active). On the power-generation side, organic Rankine cycles and piezoelectrics compete for waste-heat harvesting at different temperature regimes.
| Approach | Efficiency | Scalability | Moving parts |
|---|---|---|---|
| Thermoelectric | 5–8% | Chip-to-kW | None |
| Vapour-compression | 30–50% (cooling COP) | kW–MW | Yes |
| ORC (waste heat) | 10–20% | kW–MW | Yes |
Companies using
Connected ideas
Sources
Frontier (open questions)
- To be added.