Co2 compressor, transcritical, subcritical, for natural refrigerants

Semi-Hermetic CO2 compressors transcritical and subcritical

CO2 specialists for all performance ranges

BOCK compressors are used worldwide as key components for commercial and industrial refrigeration applications and systems in the fields of air conditioning, cooling, heating, heat recovery and heat pumps. BOCK relies on the use of future-proof natural refrigerants such as CO2 (R744). Sustainability and the environment play a major role for us. That is why we have pushed the development of our efficient and reliable CO2 compressors in recent years. With BOCK compressors, functionality, economic efficiency and climate go hand in hand. We have taken this to heart.

CO2 transcritical and subcritical

Wide range of applications

CO2 specialists for small and large performance requirements

With their wide application limits and frequency ranges the gas cooled BOCK CO2 compressors offer suitable solutions for stationary and mobile applications.
All transcritical and subcritical CO2 compressors flexibly adapt their heating and cooling capacity to the requirements. Its wide range of applications enables
tailor-made, cost-saving solutions for the most diverse applications – and all this with the highest reliability and durability.

Bock CO2 compressors support the fulfilment of important energy and environmental protection requirements, such as the European F-Gas Regulation or the worldwide Kigali Agreement, and meet strict requirements of European standards and ASERCOM guidelines.

Even for small capacities, Bock relies on the proven oil pump for a reliable oil supply in the compressor - even under demanding conditions. The basis for this is a CO2-optimized driving gear design combined with proven BOCK compressor technology.

Every compressor capacity size
is equipped with all CO2 relevant features!

Co2 Bock IconBock Co2 Verdichter Natürliches KältemittelBock Co2 Verdichter EffizienzBock Co2 Verdichter Zuverlässigkeit



BOCK transcritical CO2 compressor range
Co2 comressor subcritical  low temp
  • Flexible use for cascade and booster CO2 systems.
  • Supermarket applications: food refrigeration and air conditioning
  • Commercial and industrial refrigeration systems
  • Wide use for deep freeze applications
  • Heat pumps
  • Mobile applications: Air conditioning & heat pumps in buses and trains

Co2 compressors Quick-Checks

Product highlights and interesting facts

CO2 transcritical compressor range - benefits
  1. Frequency range 20 (30) - 70 Hz
  2. Oil pump for reliable lubrication system
  3. Compact dimensions and standard connections
  4. Low weight, maximum permissible inclination
  5. Lowest oil carry over rate
  6. Displacement at 50 Hz: 1.7 to 38.2 m³/h
  7. Wide capacity range
  8. CO2-specific pressure design LP/HP: 100 /150 bar
CO2 subcritial compressor range - benefits
  1. Frequency range 25 (30) - 70 Hz
  2. 2Oil pump for reliable lubrication system
  3. Compact dimensions and standard connections 
  4. Low weight, maximum permissible inclination
  5. Lowest oil carry over rate
  6.  Displacement at 50 Hz: 1.6 to 49.2 m³/h
  7. Wide capacity range
  8. Co2-specific pressure design LP/HP: 40 (30) / 55 bar
range-diagram-compressors-co2-transcritical (172)

Transcritical: 4 sizes
19 displacement stages

LP/HP: 100 /150 bar

With their optimised efficiency, the gas-cooled semi-hermetic CO2 compressors achieve the highest EER/COP values within their range of applications - officially confirmed by ASERCOM (Association of European Refrigeration Component Manufacturers) certification for several displacement stages.
Further advantages of reciprocating compressors: highest  reliability and durability.

CO2 subcritical compressor range

Subcritical: 4 sizes
17 displacement stages

LP/HP: 40 (30) / 55 bar

LT series: 1 model
6 displacements

LP/HP: 100 /100 bar

The subcritical series is based on the advantages of the proven BOCK HG compressor technology, which has been holistically optimised to meet the requirements of CO2 operating conditions in low temperature applications.

For special specifications with high standstill pressures, the LT series was developed - available in the two motor versions ML and S for a wide frequency band and greater operating limits.



Bock Co2 Verdichter Kältemittel R744

CO2 is a natural refrigerant, environmentally friendly, inexpensive, compared with fluorinated refrigerants. It is colourless, non-flammable and non-toxic. CO2 is the basis for determining the CO2  equivalent of refrigerants.

R744 has a GWP value of 1 and is excluded from the so-called "Phase-Down-Zenario" (F-Gas-Regulation). From a weight of 5 tonnes CO2 equivalent, the leak test of a refrigeration system is mandatory. Therefore, the leak test is not required for refrigeration systems with R744 below a charge of 5 tonnes. If CO2 is released into the environment during service work, there is no need for costly refrigerant recovery.

Demanding factors are the high operating pressure of the refrigerant, the low critical point, dry ice formation when the temperature falls below the triple point and the very high standstill pressures. The requirements and component selection of the refrigeration system must be considered accordingly.

It's good to have an expert on hand here, or even a whole tool. Feel free to ask our experienced cooling experts in the field of CO2  or find out more about our BOCKCO2 Tool and get an activation at:

CO2 transcritical compressor range - type key
  1. Compressor series (suction gas cooled)
  2. Ester oil filling
  3. Size
  4. Number of cylinders
  5. Displacement
  6. Number of poles
  7. Motor variant: ML / S / SH
  8. Refrigerant R744 (CO2)
  9. T= Transcritical
CO2 compressor range - type key
  1. Compressor series (suction gas cooled)
  2. Ester oil filling
  3. Size
  4. Number of cylinders
  5. Series (efficiency series)
  6. Displacement
  7. Number of poles
  8. Motor variant ML / S
  9. Refrigerant R744 (CO2)

The °Clever Art of Cooling: Refrigeration Expert Info for handling CO2 compressors

  • CO2 systems require new systems and a way of system control.
  • They are not a general solution for the substitution of F-gases.
  • For the safe and proper handling of CO2 compressors, please observe the information in the installation instructions.
  • The information currently provided and the values stated refer to our current state of knowledge and may change at any time due to further product development and changes in regulations. Errors and changes are therefore not excluded. 

Brochures / Catalogues

BOCK Mobile HG CO2 Compressors - CN

Product brochure (chinese)

PDF  |  2.03 MiB

BOCK Mobile CO2 Compressors HR - starCO2mpressor - CN

Product brochure (chinese)

PDF  |  2.05 MiB

BOCK transcritical CO2 compressors with LSPM motors

Product brochure

PDF  |  3.61 MiB

BOCK flexxCO2NTROL - new capacity regualtor technology for CO2 compressors

Product brochure

PDF  |  2.94 MiB

BOCK CO2 compressor program

Product brochure

PDF  |  11.45 MiB

BOCK Mobile CO2 Compressors

Product brochure

PDF  |  11.12 MiB

CO2 compressor range BOCK HGX24e CO2 LT

Product brochure

PDF  |  1.5 MiB