Dorin CO2 — the Italian transcritical specialist
By DigiEntropy Engineering · 2026-03-08 · 5 min read
Officine Mario Dorin (Florence, Italy) builds reciprocating compressors that almost exclusively target transcritical and subcritical R744 applications. The CD-series is the EU reference for compact CO2 commercial refrigeration. A focused brand worth knowing.
About this post — Authored by an AI assistant using DigiEntropy's polynomial corpus, the universal compressor predictor, and the project's chart-generation tooling. Charts are produced by Python scripts that read the same database the live site queries; tables and formulas are pulled from the same engineering modules. Findings reflect the project's current dataset and methodology — send corrections or deeper questions to admin@digientropy.com. Officine Mario Dorin (Florence, Italy) has spent the last 15 years narrowing their product line: where competitors have broadened across refrigerants, Dorin has gone deeper on one — R744 / transcritical CO2. The result is a brand that does one thing exceptionally well, and is widely spec'd when that one thing is what you need. The CD-series (transcritical) and CC-series (subcritical) are Dorin's main DigiEntropy presence. Compact reciprocating CO2 compressors covering 3 kW to 80 kW per unit — exactly the band where R744 commercial refrigeration packs live. Why a specialist brand matters Most refrigeration brands cover the full refrigerant landscape — HFCs, HFOs, naturals — across many compressor families. The advantage: one supplier relationship for everything. The disadvantage: tradeoffs in any individual application. Dorin's transcritical-CO2 specialisation gets you: - Optimised for high pressure (100+ bar discharge): cylinder + valve + crankcase engineering tuned for CO2's pressure regime, not adapted from HFC heritage. - Compact form factor: CO2's high volumetric capacity allows small displacements; Dorin's compressors are physically smaller than equivalent-capacity HFC compressors. - Mature transcritical envelope: 15+ years of field deployment data on transcritical R744 systems. - Active CO2 community: Dorin engineering team is publicly active in IIR working groups, R744 conferences, etc. The brand has a strong identity in the CO2 ecosystem. For supermarket packs, refrigerated transport, industrial process cooling on CO2 — Dorin is often the spec'd brand even when Bitzer / Frascold alternatives exist. The CD-series Transcritical-rated, semi-hermetic reciprocating. Capacity range: 5-50 kW per compressor. Discharge rating: 130 bar. Suction rating: 50 bar. Common variants: - CD200H, CD300H, CD380H: small-to-mid transcritical, single-stage - CD400H, CD500H: mid transcritical, two-stage internal - CD600H, CD800H: large transcritical, two-stage with inter-cooling The H suffix is "High pressure" — all CD variants are transcritical by default. Subcritical applications use the CC-series instead. The CC-series…