Carrefour backs CO2 in high ambients

French supermarket chain Carrefour is claiming average energy savings of over 45% compared to HFC systems in trials carried out in high ambients.

The latest issue of the Shecco publication Accelerate Europe reveals that clever use of the latest technology in installations in Spain and elsewhere have solved the performance challenges previously encountered in the use of CO2 in high ambients,

In Spain, Carrefour currently has transcritical CO2 systems in 18 hypermarkets and one supermarket, and subcritical systems in nine hypermarkets and 14 supermarkets.

The EU F-gas regulation and a tax on HFCs are seen as key drivers to CO2 technology in Spain. Recent advances in technology has also brought dramatic improvements to the performance of CO2 refrigeration systems.

According to Ivan Díaz, Carrefour Spain’s national refrigeration and HVAC manager, a lot of the challenges for use in high ambients were solved by utilising parallel compression, sub-coolers and ejectors to improve performance.

“It’s about checking energy consumption and system reliability,” he says. “We got good results. We started by making a prototype in Italy, a prototype in France, a prototype in Spain, and so on. Each country made its own pilot system. Then they started to feel comfortable with the technology.”

Carrefour is now dramatically reducing the number of new hybrid system installations. “By the second half of 2015, we had more projects in CO2 transcritical than in hybrid,” Paolo Martini, refrigeration and HVAC manager for international support is quoted as saying …