Starcompressor - Star

BOCK CO2 StarCO2ompressor HR40 and HR60:

Naturally innovative

The innovative "star" drive design of the StarCO2mpressor opens new possibilities in electric bus and train air conditioning: space-saving roof installation thanks to the industry's lowest overall height and lowest weight. Energy-saving and environmentally friendly heat generation with a CO2 heat pump without auxiliary heater even at outside temperatures down to -20 °C.



The cylinders of the radial piston compressor are arranged in a star configuration around the crankshaft, resulting in an extremely compact compressor design that is perfectly matched to the natural refrigerant CO2 (R744) and mobile use.Co2 Leaflet

The result for the user: Energy saving and LONGER RANGE
  • No need for energy-consuming auxiliary heaters
  • Up to 20% higher efficiency of the CO2 heat pump
  • Approx. 40 % more vehicle range


Secured competitive advantages for manufacturers and transport companies: Economically and ecologically sustainable investment

Busworld Innovation Award Label 2019

  • Innovative radial piston technology developed for mobile CO2 applications
  • Welded, robust steel housing with lowest risk of leakage
  • Lowest overall height (219mm) and weight (81kg) in this power class
  • Wide speed range for optimum coverage of the broad power requirements for vehicle air conditioning, heating and battery conditioning
  • Specially adapted oil management for the vehicle application
  • Proven practicality in successful series operation
  • robust ring valve design


Cooling Application

  • Bus and train application
  • Mobile  and transport cooling
CO2 compressor- Starcompressor-HR 40-HR60
 Logo StarCO2mpressor 4c

StarCO2mpressor - Highlights and things to know

All advantages at one click

  • Natural, non-flammable refrigerant
  • Climate neutral: no ozone depletion
    potential (ODP = 0)
  • The lowest global warming potential (GWP = 1)
  • Efficient operation of heat pumps down to an outside temperature of -20 °C
  • Up to 75% energy savings compared to electric heating
  • Meets the criteria of the "Blue Angel" Eco-label
  • Meets the subsidy requirements for electric bus air conditioners in Germany
RaRadial reciprocating piston technology, specially developed for mobile CO2 applications:
  • Efficient reciprocating piston technology, especially part-load optimised for heat pump applications
  • Very wide speed range
  • Lowest overall height, lowest weight
  • Welded housing with reduced interfaces for lowest risk of leakage
  • Space-saving roof installation in electric buses and trains
  • Robust and reliable, proven in practice
  • Four-cylinder radial reciprocating compressor HR40 and HR60
  • Max. permissible overpressure: 150 bar/100 bar (HP/LP)
  • Weight: 81 kg
  • Height: approx. 219 mm, overall length: 600 mm
  • Wide speed range from 750 to 4,350 rpm / 12.5-75 Hz (HR60 65 Hz) for
    heat pump application and thermal management
  • Maximum permissible inclination: 22° continuous operation, 30° short term
  • Pipe connection with flange connection, optional solder flange
  • Displacement at 50 Hz / 2,900 1/min: HR40: 7.3 m³/h / HR60: 10,9 m³/h
  • Cooling capacity 1)HR40: 7 - 35 kW/ HR60: 9 - 47 kW
  • Heating capacity 2)HR40: 4 - 27 kW/ HR60: 6 - 35 kW

1) +10°C/ 40°C (100 bar) / 10 K 
2) -20°C / +25°C (80 bar) /10 K 



Bock Co2 Verdichter Kältemittel R744






BOCK CO2 Verdichter - StarCO2mpressor

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 BOCKCO2Tool and get an activation at:

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