CO₂ Industrial System Maintains Efficiency in Hot Australian Locale

A transcritical CO₂ (R744) system installed at a food wholesaler in New South Wales, Australia, was able to perform efficiently despite the hot climate thanks to the design of the system, according to its suppliers.

The suppliers include South African OEM CRS/Sphere and Italian compressor manufacturer Frascold, which provided compressors to an industrial CO₂ transcritical installation in Australia for the first time. 

The system, installed by local contractor MB Refrigeration, provides storage of fresh and frozen foods, and a meat processing area. The wholesaler was not named in a statement from Frascold.

“This is an unprecedented installation, thanks to the application of the transcritical technology in a geographical area characterized by high temperatures,” said Shaun Hadfield, Managing Director of CRS/Sphere. “Traditional refrigerants or a combination of CO₂ and ammonia are generally the solutions of choice for this type of systems.”

“In line with the client’s philosophy, oriented towards sustainability, we have proposed an environmentally friendly yet efficient system, for the best return on investment,” Hadfield added.

The transcritical CO₂ booster system leverages heat recovery for space heating and hot water production as well as solar energy. System efficiency is enhanced by an additional heat exchanger, parallel compression and hot gas defrosting.

Significant efficiency increase

The system has 11 compressors in total, supplied by Frascold. It has a total capacity of 256kW (72.8TR), including 108kW (30.7TR) low-temperature capacity at -25°C (-13°F), and 148kW (42.1TR) medium-temperature capacity at -7°C (19.4°F).

The compressor configuration includes four Frascold S 30 18 TK transcritical compressors for medium temperatures, five D 5 11 SK2 subcritical compressors for low temperatures and two S 20 12 TK transcritical compressors for parallel compression.

“Parallel compression was the preferred solution since, in hot locations, the RPRV valve [flash gas valve/medium-pressure valve] operates at high opening levels for a long time, thus forcing the medium-temperature compressors to work harder and with a considerable pressure difference between the intake and exhaust,” said Giovanni Lo Nero, Sales Engineer and Area Manager for Frascold Australia. 

“Using a battery of compressors, placed between the receiver and the exhaust of the medium-temperature compressors, ensures a significant increase in efficiency at high external temperatures while reducing the consumption of medium-temperature compressors,” Lo Nero added.

“Frascold is one of our long-standing partners, when our company was chosen as the contractor for this project, we promptly suggested the adoption of their transcritical CO₂ components,” said Joel Middleton, Director at MB Refrigeration.