Semi-hermetic CO₂ compressors: HGX CO₂-series

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Eco-friendly excellence: BOCK® semi-hermetic CO₂ compressors

Danfoss BOCK® compressors are the global choice for essential components in commercial and industrial refrigeration, including air conditioning, cooling, heating, heat recovery, and heat pumps. We're committed to a sustainable future by embracing natural refrigerants like CO2 (R744).

Our dedication to environmental responsibility drives the continuous development of efficient and reliable CO2 compressors. This guarantees peak plant efficiency while minimizing investments, energy, and operating costs. Count on maximum operational reliability and runtime, securing your sustainable refrigeration needs.

Features and benefits of HGX CO₂ compressors:

Versatile applications: suitable for a wide range of applications, from cooling in supermarkets and industrial setups to air conditioning systems in transportation

Flexibility: transcritical and subcritical CO2 compressors have a broad capacity range, allowing for adaptable cooling and heating capacities to meet specific needs

High-pressure expertise: special LT* variant designed for subcritical applications with high operating and standstill pressures

Specialized solutions: offers ideal compressors like the HGX12 CO2 T, HGX24 CO2 T, and LT series for smaller performance requirements

Environmental responsibility: supports energy efficiency and environmental standards like the European F-Gas Regulation and the global Kigali Agreement

Comprehensive compliance: meets strict European standards and ASERCOM directives for quality and safety

Transcritical CO₂ compressors - Unmatched efficiency and reliability

Four model sizes-program—HGX12 CO2 T, HGX24 CO2 T, HGX34 CO2 T, and HGX46 CO2 T—featuring 19 displacement stages from 1.7 to 38.2 m³/h (50 Hz) that set industry standards. These transcritical models offer wide operating limits and frequency ranges, allowing tailored solutions for diverse applications.

Their optimized efficiency leads to the highest EER/COP values in their category, as officially certified by ASERCOM (Association of European Refrigeration Component Manufacturers) for multiple displacement stages. Furthermore, these reciprocating compressors are known for their unrivaled reliability and durability.

Cooling capacity 3-85 kW / Heating capacity 9-182 kW - LP/HP: 100/150 bar.

Subcritical and LT CO₂ compressors - Ideal for low-temperature needs

Designed for low-temperature applications, the program includes four subcritical models with 17 displacements from 1.6 to 49.2 m³/h (50 Hz): HGX12e CO2, HGX22e CO2, HGX34e CO2, and HGX44e CO2. They're optimized for CO2 conditions and offer versatile solutions with exceptional reliability and durability.

For specific low-temperature requirements with evaporating temperatures from -50°C to 0°C and condensing temperatures up to 25°C, we offer an efficient LT variant designed for subcritical CO2 systems with high standstill pressures (LP 100 bar), available in two motor versions (ML and S) to accommodate a wide frequency band and extended operating limits.

Cooling capacity 2.7-90 kW - LP/HP 40 (30)/55 bar.

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. 



Type Name Language Valid for Updated Download File type
Brochure BOCK CO2 compressor program English Multiple 15 Sep, 2023 11.5 MB .pdf
Brochure BOCK UL CO2 compressor program English Multiple 15 Sep, 2023 5.9 MB .pdf


Compressor selection tools - VAP

The VAP tool is ideal for finding the appropriate compressors or units for stationary 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.

Case studies

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    Danfoss, to meet the needs of G&D Chillers, used the microchannel heat exchanger and DSH inverter scroll with intermediate discharge valve to customize the Optyma™ Slim condensing unit, making it compatible with the high-efficiency refrigerant R-410A.

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    Engineering Tomorrow facilitates quiet, modular retrofit of office building’s VAV system

    When the owners of One Tower Bridge—a 15-story office building in West Conshohocken, Pennsylvania—needed to replace its 30-year-old HVAC units supplying the facility’s floor-by-floor VAV system, they turned to United CoolAir’s VariCool EZ-Fit units using Danfoss variable speed scroll compressors due to their flexible modular design and ability to handle capacity, efficiency, and noise challenges.

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    University’s marine science lab finds extreme savings with variable-speed chiller plant

    Located close to various waterways, the University of North Carolina Wilmington (UNCW) takes marine science seriously. Its new MARBIONC Building — a 69,000-square-foot interdisciplinary research facility for marine biotechnology — provides labs for lease to commercial enterprises that require reliable, energy-efficient 24/7/365 cooling. Faced with high humidity and mid-Atlantic climate variations, the building required a chiller plant that could take advantage of a wide range of operating conditions and still run reliably.

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    Walk-in coolers: a summary

    Use this list to learn what goes into making an efficient walk-in cooler or freezer.

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    Walk-in coolers: compressors and heat exchangers
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    Improving indoor air quality by increasing the amount of outdoor air (OA) entering a building is necessary in many facilities. Depending on occupant density, some buildings may require 20 cubic feet per minute (CFM) of outdoor air per person, a volume of air that can increase air-conditioning costs.

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