French supermarket puts faith in natrefs for logistics centre

Atlantic Compressors – which is based in France – is a technical sales organisation active primarily in the industrial refrigeration sector. It teamed up with consultants Cabinet Etudes Techniques pour l’Energie le Froid et les Fluides (CETEFF) to deliver the NH₃/CO₂ system. 

The supermarket chain plans to significantly invest in upgrading its distribution centres. The investment should hold for the next 20-30 years. NH₃ and CO₂ are the preferred option because they are future-proof refrigerants, and the technology is efficient and boasts a proven track record.

And the plan is to go for natural refrigerants-based technology from now on.

“This design was particularly interesting since it brought together on the same project our main products: the compressor units and the final skids assembled by Samifi France, the cascade heat exchangers made by Holger Andreasen, and the heat recovery from the oil cooling came from HS-Cooler,” Maarten Croes, president of Atlantic Compressors, told ammonia21.com.

Compared to the previous system with glycol, the NH₃ evaporating temperature increases by 2K, boosting the COP by 5% at full load. The energy savings are significant compared to the old set-up with DX Freon coolers and commercial compressor racks.

In addition, the CO₂ distribution pumps consume much less power than the big glycol pumps and indirect savings on fossil fuel are also achieved thanks to the heat recovery.

Features of the installation:

• Spray-chiller technology integrated in the NH₃-CO₂ cascade: more cost-efficient and protected against leaks (CO₂ condenses inside the tubes) and lower NH₃ charge and height compared to other solutions.
• NH₃ capacity is 4200 kW spread over two separate plant rooms.
• Possibility of full heat recovery.
• All fully factory assembled, reducing the amount of labour needed onsite. Each skid of 2100 kW is composed of three NH₃ screw compressor units, one PHEX condenser, one spray-chiller with its NH₃ pumps, and  one CO₂ receiver with CO₂ distribution pumps.
• Dimensions: 12.820 x 3.660 x 4.125 mm; empty weight 37 Tons.

Atlantic Compressors has several projects in the pipeline and one is currently under construction.

“In France I see that NH₃-CO₂ cascade systems have become a standard solution for distribution centres. The main technical problem that needs to be looked after is the risk of CO₂ leak into the NH₃ system, especially in the case of smaller systems,” said Croes.

However, research presented at the Gustav Lorentzen conference on natural refrigerants suggests that such fears will soon be consigned to history.  Angus Gillis of UK-based Star Refrigeration presented research into new control measures to mitigate cross-contamination between cascade CO₂-NH₃ refrigeration systems.

Indeed, together with Holger Andreasen, Atlantic Compressers already offer CO₂ leak detection capable of triggering a controlled shutdown of the system. Croes nonetheless sounded a cautious note. “Zero risk doesn’t exist. We can only improve the handling of the consequences.”