OUB – oil separator/receiver range
Oil separator type OUB is designed to minimize oil carry‑over by preventing lubricating oil from circulating with the refrigerant, supporting higher heat‑transfer efficiency, more stable operation and improved overall system performance. In addition, the design ensures reliable return of lubricating oil to the compressor sump under all operating conditions, maintaining proper lubrication and enhancing compressor protection.
Our OUB oil separator range covers both compact welded units for conventional refrigeration systems and high‑pressure designs for transcritical CO₂ applications. This allows you to apply the same separation principle and performance benefits across a wide span of system sizes, pressures and refrigerants, from smaller stand‑alone units to demanding CO₂ rack installations.
Key features:
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High‑efficiency oil separation for more stable operation and longer compressor lifetime
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Reliable oil return and compressor protection across the full OUB range
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Broad application coverage with compact welded designs for smaller systems and robust flanged designs for demanding CO₂ racks
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Rugged construction and high working pressures make the CO₂ variants ideal for modern transcritical CO₂ installations
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Design options with integrated receiver (OUB‑TSR, OUB‑THR) support compact, flexible system layouts
CO₂ oil separator - Designed for demanding CO₂ applications
Managing oil in CO₂ transcritical systems is essential to keep compressors running, avoid downtime and maintain high system efficiency. Our new OUB range is purpose-built to address these needs, combining robust high-pressure performance, fine filtration and flexible design options for refrigeration, heat pump and chiller applications.
OUB is ideally suited for CO₂ transcritical units with multiple compressors in parallel, making it a strong choice for food retail refrigeration, large industrial chillers and commercial or industrial heat pumps. By effectively separating and returning oil to each compressor, OUB helps maintain consistent operation, extend equipment life and protect system performance over time.
Two construction types, three variants
We offer OUB in both serviceable and hermetic designs to suit different installation and maintenance needs.
The serviceable models (OUB-TSR with receiver and OUB-TSN without receiver) filter oil particles down to 0.3 microns. They use a three-stage coalescing design that progressively merges fine oil droplets into larger ones, improving separation efficiency and reducing the risk of premature filter loading. An advanced multi-layer filter construction combines stainless steel mesh, fibre fleece and perforated metal for strength and resistance to clogging, even under harsh CO₂ conditions. With a large 3300 cm² filtration area in a V-shape layout, service intervals are extended compared to traditional designs. Technicians benefit from clear access points, replaceable filter inserts and standardized connections, which simplify maintenance and reduce downtime.
The hermetic model (OUB-THR with receiver) uses demister technology to achieve filtration down to 3–10 microns. Its fully sealed design eliminates the need for routine maintenance or filter changes, offering a balance between effective filtration and long service life.
OUB: High‑performance oil management
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Up to 140 bar MWP – built for CO₂ transcritical systems
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Available in multiple sizes to fit your application
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Rugged, long‑life design for reliable performance
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Seamless integration with COM controls, sensors, filter driers and valves
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Quick installation with standardized connections
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Easy servicing with clear access points and fast filter replacement
Part of our complete CO₂ portfolio
OUB expands our CO₂ oil management range and works seamlessly with other Danfoss components, reinforcing our role as a full-system partner for high-pressure CO₂ applications.
Product range
The COM Compressor Oil Management solution ensures an optimal oil level control and regulation in semi-hermetic, scroll, and reciprocating compressors.
Documents
| Type | Name | Language | Valid for | Updated | Download | File type |
|---|---|---|---|---|---|---|
| Catalog | Danfoss CO2 catalogue - Components and controls for CO2 applications | English | Multiple | 24 Nov, 2025 | 1.4 MB | |
| Catalog | Danfoss CO2 catalogue - Components and controls for CO2 applications | Italian | Italy | 17 Jul, 2024 | 4.3 MB | |
| Catalog | Danfoss CO2 catalogue - Components and controls for CO2 applications | Dutch, Flemish | Netherlands | 17 Apr, 2025 | 6.7 MB | |
| Catalog | Danfoss CO2 catalogue - Components and controls for CO2 applications | Spanish, Castilian | Multiple | 18 Jul, 2024 | 1.2 MB | |
| Catalog | Danfoss CO2 catalogue - Components and controls for CO2 applications | French | France | 17 Mar, 2026 | 3.8 MB |