Scottish OEM Star Refrigeration has installed two dual-temperature CO2 (R744) refrigeration systems at British food wholesaler Bidfood’s new 37,500m3 (1.3 million ft3) cold storage facility in Glasgow, Scotland.

According to a statement from the manufacturer, the systems have set a new industry standard in terms of performance, consuming nearly 50% less energy than the “Best Practice” benchmark for similar sized facilities in Britain.

Performance data collected since the systems were installed in November 2022 show that the specific energy consumption (SEC) at Bidfood’s Glasgow site stands at 10.2kWh/m3/year (0.3kWh/ft3/year), compared to the national industry standard of 20.4kWh/m3/year (0.6/kWh/ft3/year). They systems are also significantly more efficient than the European average, which is around 53.3kWh/m3/year (1.5kWh/ft3/year).

“The energy efficiency achieved at our Glasgow site through the installation of a CO2 refrigeration system far exceeded our expectations,” said Claire Cox, Head of Property for Bidfood. “Partnering with Star Refrigeration has been instrumental in strengthening our commitment to sustainability while improving the efficiency of our operations across our cold stores.”

The systems’ energy efficiency and use of a future-proof natural refrigerant, translating into annual emissions reductions of around 77 metric tons of CO2e. According to Star, the project is supporting Bidfood’s ambitions to reduce its greenhouse gas emissions by at least 90% by 2045.

“The refrigeration systems at Bidfood demonstrate the potential for businesses aiming to transition towards energy-efficient and climate-friendly operations by using CO2 cooling technology,” added Dr Rob Lamb, Group Sales and Marketing Director at Star Refrigeration. “Bidfood’s decision to prioritize sustainability has not only set a commendable benchmark, but [it] has also delivered tangible benefits, showcasing reduced energy costs and carbon emissions that outperform the industry’s Best Practice standards across the country.”

“The refrigeration systems at Bidfood demonstrate the potential for businesses aiming to transition towards energy-efficient and climate-friendly operations by using CO2 cooling technology.”

Dr Rob Lamb, Star Refrigeration

Freezing, cooling and heat recovery

The two outdoor CO2 systems provide both low- and medium-temperature cooling for the facility’s freezer, cold storage and marshalling area.

For the site’s freezer, the systems offer 245kW (69.7TR) in cooling capacity at a temperature of -25°C (-13°F). Meanwhile for the facility’s medium-temperature demands, the systems provide a combined capacity of 268kW (76.2TR) at 2°C (35.6°F).

To ensure optimal air circulation and a consistent temperature throughout the facility, Star installed multiple coolers equipped with efficient electronically commutated (EC) fans. Running at a speed of 50%, these fans offer energy savings of up to 87.5% compared to traditional fixed-speed fans, explained the manufacturer.

A heat recovery system converts waste heat from the facility’s refrigeration to provide underfloor heating and warm glycol defrost for the air coolers.

The systems’ controls offer real-time data monitoring, fault dial out and remote access capabilities for swift performance adjustments and ongoing maintenance.

In addition to having worked with CO2-based cooling systems since 2002, Star Refrigeration also has multiple decades’ experience working with ammonia (R717) technologies.

To help businesses assess the most appropriate long-term refrigeration option for their needs, the manufacturer has produced a short guide that highlights the challenges and opportunities associated with the two natural refrigerants.