CO2 a natural choice for Danish food retailer

DENMARK: Danish refrigeration systems manufacturer Advansor has supplied a transcritical CO2 system with eight Bitzer EcoLine+ reciprocating compressors at a new distribution centre for REMA 1000 supermarkets.

The recently completed warehouse in the Danish city of Vejle will deliver goods to REMA 1000’s shops in western Denmark. 

REMA 1000 is a multinational no-frills supermarket chain owned entirely by the Reitan Group. It supports more than 800 subsidiaries in Denmark and Norway.

The REMA 1000 project, which began in the summer of 2018, was described by CO2 systems specialist Advansor as “the biggest compound system in company history”.

The project began in the summer of 2018 with Advansor in charge of planning and realisation of the refrigeration system in collaboration with ICS Industrial Cooling Systems. The system was built from scratch, but the building itself is a former dry-storage warehouse. 

The refrigeration system has a total capacity of 940kW at -4°C evaporation temperature and 32°C ambient temperature. And it is quite large, too, at 10.8m long. Six Bitzer EcoLline+ compressors ensure the medium temperature application, while two additional EcoLine+ compressors provide for even greater efficiency in parallel compounding.

Bitzer has has collaborated with Advansor since the German compressor manufacturer first started producing CO2 models, and REMA 1000 already uses Bitzer compressors in all of its shops.  

“Bitzer is our preferred supplier. We get around 95% of our compressors from Bitzer,” said Advansor’s business development manager Kenneth Madsen. 

He explained that this project marked the first time Advansor had opted for EcoLine+, mainly because of its high efficiency. It was also the company’s first experience with a line start permanent magnet motor (LSPM). 

The LSPM motor is said to increase seasonal performance factor by more than 10%. These motors can be connected directly to 50 or 60Hz networks, offering higher efficiencies in both full and part load operation. Permanent magnet motors are robust, easy to use and can operate both directly on the mains network and with frequency inverters. 

“Very few other technologies would be suitable for this system. They simply can’t handle the cold climate here,” explained Madsen. “The fancy stuff with ejectors and the like wouldn’t be worth trying out in an application like this. LSPM is a good technology because it works in any climate.” Advansor’s system design combined with LSPM is said to enable a new level of energy efficiency – by more than 10%. 

“Natural” refrigerants are common in Denmark due to charge size limits on HFC refrigerants which have been in place since 2007.

“In Denmark, it’s probably easier than in other countries for these systems to gain a foothold. But it can still be difficult here.,” explained Kenneth Madsen. “Hydrocarbons would not be an option. Ammonia, perhaps, but most distribution centres and smaller businesses rely on CO2 because it is cheaper to both acquire and operate. Five or 10 years ago, this project would have opted for an ammonia system – but now the focus is on CO2 for such cases.”

“The demand for industrial CO₂ systems is constantly increasing, especially with permanent magnet motors, because they save on operating costs and reduce the impact on the climate,” claimed Advansor’s Denmark country manager Casper Christiansen. “Of course, compressors with these motors are more expensive to acquire – but this investment pays off within just a short period of time.”