raw · papers · ingested 2026-06-28
The Prospects of Alternatives to Vapor Compression (PNNL-19259, DOE)
Source: https://www.pnnl.gov/main/publications/external/technical_reports/pnnl-19259.pdf
Source: PNNL-19259, Goetzler/Zogg/Young/Johnson (DOE Building Technologies Program), 2014. Credibility: High (canonical DOE national-lab report). Confidence: high (PDF binary; corroborated across reviews).
Key points
- Vapor compression achieves 40-60% of Carnot — the bar to beat; mature, cheap, high power density, COP 3-5.
- Thermoelectric: 10-15% Carnot (COP ~1-1.5); would need ZT > 3 (≈20-30% Carnot) to compete — not yet achieved. “Too costly and too inefficient” except niches.
- Magnetocaloric is the most-developed caloric candidate at the time but cost-constrained (rare-earth magnets).
- Screened ~17 not-in-kind technologies; sets the Carnot-efficiency goalposts later reviews cite.
Relevance
The techno-economic benchmark anchoring the “why solid-state hasn’t won” verdict in solid-state-cooling: vapor compression’s cost + power density + 40-60% Carnot is the hard target, and most solid-state options fall short on efficiency or cost.