Semi-hermetic aluminium compressors for mobile use

  • Overview
  • Software
  • Related applications
  • Learning

Innovative HG-series compressors: Lightweight solutions for mobile cooling

Danfoss BOCK®'s HG-series aluminum compressors are ideal for mobile refrigeration. They're 40% lighter, low-profile for vehicle roofs, and feature a robust K-design valve plate for bus air conditioning and electric applications.

They handle large inclination angles of the vehicle with special oil management, and the K valve plate has a proven track record in vehicle applications.

Features and benefits of HG compressors for mobile use

Lightweight design thanks to the all-aluminum construction, enhancing mobility and efficiency.

Increased performance: The 2-pole version offers a significant performance gains and improved capabilities for various applications.

Space-efficient: these compressors feature a compact design with a reduced-height terminal box, making them ideal for space-constrained environments.

Enhanced safety: BOCK® mobile aluminum compressors meet EN45545's highest fire protection class HL3, ensuring top-tier safety for railway air-conditioning systems.

Available for R134a, R513A, R452A, R1234yf, R290, as well as R404A, R407A/C/F.

  • Available as 2- and 4-cylinder compressors in cast iron or all-aluminum lightweight construction
  • Semi-hermetic compressors with 2-pole drive motor:
    Based on the HG standard compressors with their outstanding advantages and features, versions with 2-pole drive motor are available with up to 70% increased cooling capacity with the same external dimensions. This is made possible by doubling the speed at the same mains frequency. Together with the robust and reliable BOCK® K valve plate, this results in the optimal solution for bus air conditioning and many other mobile applications.
  • Lightweight aluminum construction 40% lighter than cast iron version
  • Power control also possible digitally in wide bandwidth
  • Reliable and efficient reciprocating piston technology with optimized valve plate system and low oil throw
  • Highly efficient 4-pole and 2-pole electric motors
  • Wear-resistant and durable power unit
  • Powerful and compact 2-pole drive motor (2,900 1/min - 50 Hz)
  • Reduced overall height (300 mm) with optional terminal box
  • Lockable metal terminal box for access restriction
  • Terminal blocks with enhanced serviceability and rail approval, resistant to shock and vibration
  • Fire protection class HL3 According to rail standard EN 45545-2
  • Pressure circulation lubrication with oil pump as standard
  • Electronic motor protection
  • Oil pump lubrication independent of direction of rotation
  • Minimal oil throw
  • Service-friendly oil strainer
  • Oil pressure monitoring possible
  • Large-volume oil sump
  • PTC oil sump heater, self-regulating for HG12 to HG34e

The 2-pole design compressors offer unparalleled refrigerating capacity for power-intensive applications like mobile air conditioning. Available in both cast iron and lightweight aluminum construction, these compressors also come with optional low terminal boxes and a reduced overall height of 300 mm.

K valve plate advantages:

  • Specially designed for bus air-conditioning
  • Exceptional operational safety with loosely guided annular disc packs
  • Working valves made of high-quality, impact-resistant spring steel
  • Resilient and reliable under constant speed and pressure fluctuations, as well as exposure to liquids
  • Lightweight, aluminum valve plate for weight optimization

N valve plate advantages:

  • Worldwide proven valve design with reed lamellas clamped on one side
  • High-quality, impact-resistant spring steel valves
  • Suitable for universal use in mobile applications
  • Cost-effective and simpler alternative to the K version
  • Valve base plate made of steel

Looking for spare parts?

BOCKSHOP Spare parts catalog


The online spare parts catalog allows you to find the right spare parts and accessories for BOCK compressors and units with just a few clicks. 



Compressor selection tools - VAP

The VAP tool is ideal for finding the appropriate compressors for mobile applications. By inputting the required refrigerating capacity and operating conditions, the tool will display compatible components right away. In the VAP tools you will also find additional details about the suggested compressors.

Related applications


Join the CO₂ Technology Training at our Training Center in Frickenhausen

On-site CO₂ Basic training with the tour of the training application, available in English and in German.

Gain a good awareness knowledge about CO₂ technology and register to one of our face-to-face courses. A complete transcritical supermarket cooling system, incl. heat recovery, air conditioning, parallel compression and ejector is available at our training center in Frickenhausen.