Foodstuffs New Zealand decides to roll out proven CO2 transcritical technology

By Klara Skačanová, May 12, 2014, 11:36 3 minute reading

After opening a CO2 transcritical store at Newlands, Wellington in 2012, retailer Foodstuffs is now confident with the technology and considers this to be a proven concept for its supermarkets. The retailer has plans to deploy CO2 refrigeration in a number of new and refurbished stores.

The energy savings measured at the New World Newlands store featuring a CO2 transcritical system, which opened its doors in August 2012, fulfilled the retailer’s expectations, and the Foodstuffs group is now looking to replicate the system in other store developments.

“Foodstuffs regards the concept of transcritical refrigeration in our supermarkets as now completely proven and we are actively rolling out the systems in new builds (New World stores in Massey, Auckland and Kumeu, Auckland and Wainoni and Redcliffs in South Island) and in refurbishments (PAK’nSAVE, Clarence street, Auckland), where practical,” Foodstuffs Sustainability Manager Mike Sammons told to

Comparison with CO2/134a hybrid system shows considerable savings

The benefits of a transcritical CO2 refrigeration system compared to a hybrid refrigeration system are significant. Following a year-long performance comparison between a CO2 transcritical system at a New World Newlands supermarket and a hybrid (CO2/R134a) cascade system installed at another Foodstuffs store, both operating under the same climatic conditions, it was found that 8% more energy was saved in the CO2-only store. To date, the full transcritical system has returned figures in the range from 5 - 25% energy savings.

Commenting on the performance of the CO2-only store Sammons noted: “This technology coupled with lids and doors on freezers, LED lighting and sub-metering effectively reduces the store's operational carbon footprint by an estimated 50% compared with stores of only 5 years ago.”

Award winning refrigeration system

The New World supermarket in Newlands was recognised for its sustainability and energy efficiency efforts when it became the winner of the Mega Efficiency Innovation Award at the annual NZI National Sustainable Business Network Awards 2013. "It’s fantastic to be recognised for this environmental forward thinking and we hope other businesses will follow our lead," Mike Sammons said.

The NZI Sustainable Business Network Awards are the pre-eminent and longest-standing awards in New Zealand that recognise the efforts of businesses that have demonstrated progress in sustainability.

About the transcritical CO2 system

Some of the key features and specifications of the transcritical CO2 system installed at the 2,400m2 New World Newlands store include:
  • Rack system by Bitzer Australia
  • Seven CO2 compressors by Bitzer installed in a booster configuration (four 4FTC- 30K and one 4FTC-15K compressor make up the MT rack, one 2HSL and two 2HHC compressors make up the LT rack)
  • LT cooling capacity of about 21kW at -36°C, MT capacity of about 150kW at -10°C
  • Waste heat recovery from the high pressure side of the system to heat domestic hot water to 70°C
  • Total CO2 refrigerant charge of less than 150kg
  • Floating suction pressure control from the coldest cabinets
  • Floating gas cooler pressure from ambient outside air temperature and retail space heating requirements
  • Full refrigeration system control by Emerson, including E2 for the rack system and Dixell for cabinet controllers
  • Full HVAC system control by Emerson E2, including car park and retail space CO and CO2 sensors; full remote monitoring via Emerson ProAct Web based interface.
  • Alfa Laval Gas cooler and room evaporators with EC fans


By Klara Skačanová

May 12, 2014, 11:36

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