Staying cool without refrigerants: Next-generation Peltier cooling

Original Article ↗ Hacker News Discussion ↗

Background: Peltier Cooling Use and Decline

  • Commenters recall using Peltiers on late‑90s CPUs (e.g., K6), working “well enough” at ~20–30W TDP.
  • As CPU TDPs climbed to 100–300W+, Peltiers became impractical: they add substantial waste heat and have limited heat‑pumping density.
  • Main historical appeal: cooling below ambient for overclocking. Problems: condensation, algae/mold growth, and complex dew‑point management.

Efficiency, Scaling, and COP Debate

  • Thread repeatedly notes Peltiers don’t destroy heat, they move it and generate extra heat.
  • Typical thermoelectric COP is said to be ~0.5–0.7 (10% “efficiency” vs Carnot), far below vapor‑compression systems (COP ~2–4, ~45% of Carnot).
  • Others correct earlier misconceptions: at small ΔT, standard TECs can reach COP >1 (e.g., 20W pumped with 8W input), but this collapses quickly as ΔT grows.
  • Key constraints: thin devices with non‑zero thermal conductivity cause significant back‑leak; stacking modules increases ΔT but explodes power and complexity.

Samsung / JHU Claims and Skepticism

  • Article and JHU release claim ~75% better efficiency and COP ~15 at ΔT ~1.3°C using thin‑film structures.
  • Many see this as impressive only at tiny ΔT and likely far from practical refrigerator conditions (ΔT ~20–40°C).
  • Some critique the measurement methodology (indirect heat-flow estimates, small temperature differences, potential large systematic error).
  • Several ask what “75% better” concretely means and want real‑world kWh vs compressor fridges.

Hybrid Fridge Design and Temperature Control

  • Samsung’s “hybrid” fridge uses a compressor for bulk cooling and Peltiers for peak loads or fine control.
  • Some argue they’d prefer a larger or better‑controlled compressor; others note oversized compressors can short‑cycle.
  • Discussion branches into annoyance with wide fridge temperature swings, food-safety guidance (≈3–5°C), and uneven internal gradients.
  • A few see value in Peltiers for precise stabilization and more uniform temperatures if energy use is acceptable.

Noise, Silent Cooling, and Alternatives

  • Strong demand for quieter fridges, especially in studios; Peltiers and absorption fridges are mentioned as silent options, each with trade‑offs in cost, reliability, and efficiency.
  • Ideas include moving compressors outdoors or centralizing heat pumps for multiple home appliances; others note refrigerant plumbing, complexity, and regulatory hurdles.

AI Branding and Marketing Critique

  • Widespread mockery of terms like “Bespoke AI Hybrid Refrigerator” and “AI compressor”; most see only simple sensor‑driven logic or PID control.
  • Some note real uses of AI in materials discovery and process optimization, but agree the product’s “AI” appears to be pure marketing.
  • General sentiment: solid underlying thermo research, buried under buzzwords and vague efficiency claims.