METRO AG commissions China's first transcritical CO₂ ejector and second parallel compression systems

METRO China, a division of German retailer METRO AG, has confirmed that it has commissioned two new transcritical CO₂ stores in China, one that uses an ejector (China's first) and one that employs parallel compression (CHina's second).

Last April, Alan Lin, head of facility management for METRO China, told participants at the ATMOsphere China 2019 conference (organized by shecco, publisher of this website) that the company had "two [transcritical CO₂] stores under construction."

"One is in Chongqing, where we use the ejector system with Carrier as our supplier," said Lin. "The second store is in Beijing, where we chose the parallel compression system supplied by CREA."

METRO China has now confirmed that both projects were completed in June and have provided additional details about the two installations.

 First transcritical CO₂ ejector store 

METRO China's Chongqing store is located in the Nan'an district and originally opened in 2001. The store building area measures 15,536 m² and  has a sales area of 8,597 m².

The store's transcritical CO₂ system was provided by Carrier and it replaced an existing R22 system. "Due to the high temperature of Chongqing in the summer, we chose to use the ejector system" – a first for China – "as a solution for this store," according to a statement from the company. Energy savings compared to the previous system is estimated to be 25%. Carbon emissions are expected to be reduced by around 917 tonnes of CO_2e per year.

Carrier's transcritical CO₂ racks installed at METRO China's store in Chongqing. Photo via METRO China.

The system has a low-temperature cooling capacity of around 140 kW and a medium-temperature cooling capacity of around 350 kW. CO₂ gas coolers and evaporators were provided by Güntner, controls by Danfoss and refrigerated cabinets by Haier Carrier. Installation was also carried out by Haier Carrier.

In addition, the CO₂ system employs the use of heat reclaim to provide hot water for the store's daily use.

 Second parallel compression store

METRO China has also commissioned a new transcritical CO₂ store in Beijing. Identified as the Beijing Shilihe store, it was originally opened in 2006. The two-story building has a total area of 11,196 m² and a sales area of 6,587 m².

The transcritical CO₂ system was provided by Italy-based refrigeration system supplier CREA and it also replaced an existing R22 system.

The system employs the use of parallel compression and is the second transcritical CO₂ system in China to do so after METRO China opened its first transcritical CO₂ store in Beijing in January 2018.

Energy savings compared to the previous system is estimated to be 25%. Carbon emissions are expected to be reduced by 830 tonnes of CO_2e per year.

The system has a total low-temperature cooling capacity of around 100 kW and a medium-temperature cooling capacity of around 130 kW. In addition, the system provides around 220 kW of high temperature cooling for a prep room and sales area.

CO₂ gas coolers were provided by Modine and evaporators by Güntner. Controls were provided by Carel, refrigerated cabinets by Panasonic and installation was carried out by Shanghai-based installation contractor Shanghai Qingneng Cool Chain Equipment & Engineering, which partners with CREA.

METRO China now has a total of three transcritical CO₂ systems installed and running in the country.