15-Fold increase in solar thermoelectric generator performance

Original Article ↗ Hacker News Discussion ↗

How STEGs / Thermoelectrics Work

  • Thread clarifies STEGs use the Seebeck effect: two dissimilar semiconductors with a temperature difference produce a voltage as charge diffuses from hot to cold.
  • Related to, but distinct from, Stirling engines (mechanical conversion) and the Peltier effect (same physics in reverse for cooling).
  • Commenters note traditional room‑temperature thermoelectrics have extremely low power density, making meaningful output hard without large ΔT.

Comparison to Photovoltaics and Solar Use-Cases

  • STEGs are seen as complementary, not competitive with PV: they can harvest energy from temperature gradients, scattered light, and “low‑grade” heat where PV does poorly.
  • Several point out that PV already works in shade/clouds and standard panels likely still outperform STEGs in almost all solar scenarios.
  • Hybrid ideas (PV on front, TEG on back) come up; most argue extra complexity is less cost‑effective than just adding more PV, though some cooling concepts could benefit PV efficiency.

Efficiency, “15‑Fold” Claim, and Skepticism

  • Multiple readers note the paper seems to improve “performance” (raw output) more than true thermodynamic efficiency, likely still orders of magnitude below PV.
  • Some criticize that the reference for “15‑fold” is effectively “bare Peltier in the sun” and that the paper avoids clear end‑to‑end efficiency numbers; powering a single LED under concentrated light is seen as a tell.
  • Clarification that “15‑fold” means 15×, not 2¹⁵×; brief digression on “fold change” terminology.

Heatsinks, Cooling, and Non-Solar Applications

  • Many are more excited about the 2× improvement in passive radiative+convective cooling of an aluminum heatsink than about the STEG itself.
  • Suggested applications: CPU/GPU coolers, car components, AI/datacenter waste heat harvesting, and general thermal management.
  • Debate on scalability of femtosecond laser texturing: some say it’s already industrial (e.g., glass cutting), others doubt its economics for large-area surface modification, proposing alternative “black” coating methods.

Nuclear, RTGs, and Grid-Level Energy Debates

  • Idea floated: very simple nuclear plants using TEGs to avoid pumps and moving parts; replies note such systems would be drastically less power-dense and still face fuel security and economic issues.
  • Discussion of RTGs and pebble‑bed reactors: RTGs already use thermoelectrics for small, ultra‑reliable power; pebble‑bed designs and SMRs mentioned as “inherently safer” but not yet widely deployed.
  • Large subthread veers into renewables vs nuclear:
    • One side argues solar+wind+batteries (and interconnection) are winning on cost and investment, making new nuclear uneconomic and too slow to build.
    • The other emphasizes baseload, weather‑correlated failures of wind/solar, winter lulls, storage limits, and underpriced nuclear risk (liability caps, accident costs).
    • Both sides acknowledge grid balancing complexity, negative pricing events, and the need for storage and flexible demand.

Other Themes

  • Some see this as a nice revival of spintronics-related thermoelectric research and an example of “outside the box” materials work.
  • A few hope similar advances could enable practical solid‑state cooling, but others note Peltier devices are inherently far less efficient than vapor‑compression heat pumps.
  • One commenter speculates about military/thermal camouflage uses but hopes civilian climate applications dominate.