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MHI Thermal Systems Adds 2 Models to Its Lineup of “C-puzzle” Refrigeration Condensing Units


“C-puzzle” series

Mitsubishi Heavy Industries Thermal Systems, Ltd. (MHI Thermal Systems), a Mitsubishi Heavy Industries (MHI) Group company, will launch two new models, the 10HP “HCCV1001C” and 20HP “HCCV2001MC” to its “C-puzzle” series of commercial-use refrigeration condensing units that use the natural refrigerant carbon dioxide (CO2). Both new models, which will be sold in the Japanese market this summer, accommodate MHI Thermal Systems’ proprietary new “M-DIOMAC” system (Note 1). The new units respond to the need to simplify engineering and installation.

Models in the C-puzzle series first marketed in 2017 are equipped with MHI Thermal Systems’ proprietary two-stage compressor, a unique configuration of a scroll compressor and a rotary compressor (Note 2). The new M-DIOMAC system provides for a packaged oil management system, which is essential when building a refrigeration system. The packaging simplifies on-site adjustments of the refrigeration units, enabling simpler installation.

M-DIOMAC consists of a dedicated system controller and remote controller. Direct control of the cooling unit’s expansion valve (Note 3) enables effective oil management, resulting in outstanding reliability. As up to three condensing units, which function as outdoor units, can be interconnected, control is possible to a maximum of 60HP. The cooling units, such as the showcase and unit cooler, serve as the indoor units. With the 10HP condensing unit, up to 8 cooling units can be interconnected, while for the 20HP model up to 16 cooling units can be interconnected. Using the remote controller, which features a full-colour 7-inch liquid crystal display, monitoring from a distance is possible. Also, information on cold room temperature, set temperature, degree of superheat, opening degree of the expansion valve, etc. can be displayed for 8 units, allowing for easy confirmation of operations.

The CO2 refrigerant used in the C-puzzle features an ozone depletion potential (ODP) of zero and global warming potential (GWP) of only 1, enabling significant contributions to protecting the ozone layer and mitigating global warming compared to the fluorocarbons (HCFC, HFC) currently in wide use. Under Japan’s “Act on Rational Use and Proper Management of Fluorocarbons,” commercial condensing units having a compressor with a rated output exceeding 1.5 kW will be required to adopt refrigerants with a GWP below 1500 (CO2 = 1) by 2025. As a result, from 2025 adoption of low-GWP refrigerants is expected to expand further, and this is projected to make it difficult to procure fluorocarbon type refrigerants when the refrigerant needs to be exchanged during repair work. Condensing units using CO2 refrigerants, on the other hand, are not affected by refrigerant regulations, creating an environment conducive to adoption of such condensing units (Note 4), so demand is projected to increase both for new installations and replacements.

MHI Group, in accordance with its Carbon Neutral Declaration to achieve net zero emissions by 2040, is currently taking steps to reduce CO2 emissions both from its own plants and other facilities involved in production activities, and from customer facilities that use its Group products. Going forward, MHI Thermal Systems, as an integral Group member, will continue to focus on developing natural refrigerants and energy-saving products that enable reductions in CO2 emissions, thereby contributing to global environmental protection throughout its worldwide markets.

  • Note 1: M-DIOMAC: M-Direct Oil Management Control (trademark registration pending)
  • Note 2: MHI Thermal Systems’ two-stage compressor adopts the world’s first technologies (patented) enabling outstanding efficiency even with high-pressure refrigerants.
  • Note 3: The valve must be acquired separately from CAREL, MHI Thermal Systems’ designated manufacturer of controllers.
  • Note 4: Under changes effected to Japan’s High Pressure Gas Safety Act in 2017, CO2 refrigerants are treated the same as inert fluorocarbon type refrigerants.


Major Specifications of C-puzzle “HCCV1001C” and “HCCV2001MC”