Arneg Transcritical CO2 South Korea
Arneg’s transcritical CO2 condensing units helped reduce energy consumption at a CU convenience store in Seoul, South Korea. (Source: Arneg Korea)

ATMO APAC: Arneg Transcritical CO2 Condensing Unit Cuts Emissions at South Korean Store by 67%

The R744 units reduced the store’s energy consumption by 17% compared to an R410-based alternative.

Arneg Korea, part of OEM Arneg Group, has helped reduce the GHG emissions of a CU convenience store in Seoul, South Korea, by 67% with the installation of a transcritical CO2 (R744) condensing unit.

The condensing unit, installed in 2021, reduced the energy consumption of the 90m2 (970ft2) store’s low temperature (LT) appliances by 25.4% and medium temperature (MT) appliances by 16.2%, compared to R404A alternatives. This reduction in energy use, in addition to the use of R744 instead of a synthetic refrigerant, resulted in the two-thirds reduction in GHG emissions.

Details of the installation were presented by Gabriele Sernani, Manager of Oversea Sales at Arneg Korea during the State of the Industry – APAC online session on the second and final day of the ATMOsphere APAC Summit 2022 on June 28. The conference, which also took place in person in Tokyo on June 27, was organized by ATMOsphere, publisher of

According to Sernani’s presentation, as of December 2021, Arneg had installed around 1,700 CO2-based refrigeration systems globally. Ten of these systems are located in South Korea.

Eco-friendly retail in South Korea

Following the South Korean government’s 2020 Nationally Determined Contribution (NDC), which detailed its plans to reduce its GHG emissions by 24% by 2030 (since updated to 40%), Arneg Korea was approached by CU, Korea’s leading convenience store brand, to help the chain develop an “eco-friendly store.”

“[The client] asked for energy-saving fridges, eco-friendly gas and the reduction of CO2 emissions,” explained Sernani.

To meet the client’s needs, Arneg installed a 2HP–4HP transcritical COcondensing unit with a cooling capacity of 3.7kW (1.1TR) and evaporating temperature of -10°C (14°F) for both LT and MT; a high-efficiency DC compressor and DC fan to improve the efficiency of the condensing units and refrigerated cabinets; and a free-flow price-holder air-curtain system to help maintain the temperature inside the cabinets, which were mostly open multi-deck units.

In addition to using an eco-friendly refrigerant, reducing energy consumption and cutting GHG emissions, the condensing unit provided additional benefits to CU, including easy installation, flexible configuration and low noise.

According to Sernani, there are only two stores with these features in South Korea.

Testing transcritical COfor hydrogen charging stations

Arneg Korea is also currently testing the use of transcritical CO2 refrigeration in hydrogen charging stations as part of a project with the governments of South Korea and the United Arab Emirates (UAE).

“Many institutions and companies are investing in hydrogen as a possible alternative for the use of fossil fuels in cars, buses, trucks and other transportation,” said Sernani. “For the process of dispensing hydrogen, you need a chiller to change the hydrogen from a positive temperature to -40°C (-40°F).”

In Korea this is typically done using an R404A-based chiller system but Arneg wanted to use a COchiller to “create a green combination” of reduced GHG emissions from the use of hydrogen as a fuel, plus the use of CO2 as a refrigerant for its distribution, Sernani explained.

The charging station’s chiller system, which is manufactured by Arneg Italy, includes one combined compressor rack for both MT and LT, an AC inverter and an external gas cooler. To maintain “constant cooling capacity,” the system also uses a water-spray system with its gas cooler.

In this case, the use of COreduces the system’s refrigerant charge by 33% compared to a conventional R404A system and improved piping has reduced refrigerant leakage by 75%.

The CO2 system compared to an R404A system, improves energy efficiency “by around 15%,” said Sernani.

The project is currently in the middle of its two-year testing phase, which will conclude at the end of 2023. In 2024, the first hydrogen charging stations using Arneg’s transcritical CO2 system will be installed in South Korea and from 2025, there will be multiple installations of this system in the UAE.

According to Sernani, Arneg Korea is considering how this system can be used for industrial applications, such as for semiconductors.

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