ACR Journal

December 2021 | January 2022 REFRIGERATION 26 ACR Journal explores how Arctic Circle has been part of one of the refrigeration industry’s best-kept secrets in recent times. The Hereford-based manufacturer has been busy developing, designing, manufacturing, installing and servicing the world’s first transcritical booster system utilising Emerson’s ground- breaking Copeland CO 2 scroll compressor technology. A transcritical boost for CO 2 refrigeration technology Volume 8 No.1 Arctic Circle, with 36 years of experience in introducing innovative technology to the industry, was approached by Emerson Climate Technologies in September 2018 to collaborate for a new CO 2 scroll compressor technology. Emerson identified Arctic Circle as a development partner as it has an industry-leading engineering team coupled with a long-standing history of working collaboratively with end-users to introduce pioneering products to market. The Natural Refrigeration Technology Centre (NRTC) at Arctic Circle also presented an opportunity to ensure that the system was proven before being placed on a live site. It was agreed that Arctic Circle would manufacture a transcritical booster system to be installed in the NRTC for testing and concept demonstration. This development system was installed in the NRTC in July 2019 after a complex multi-disciplinary engineering design. Intensive testing took place, including modelling seasonal UK ambient temperatures and varying load profiles to demonstrate the efficiency improvements offered by enhanced vapour injection. Its inclusion allows similar efficiency benefits of a parallel compression system without the additional cost and complexity. Data was captured and fed back to Emerson to refine the technology before the product moved to field trials. Co-operation The Co-operative Group was the natural choice for a field trial of the technology. In 2017, the Co-operative Group committed to replacing their vast HFC based refrigeration systems with new CO 2 technology. Typically, stores in the Co-operative Group’s estate are in locations where the footprint and noise of the refrigeration system are essential factors. These challenges, in recent years, would have needed to be prioritised at a higher cost for any project. The Co-operative Group was interested in trialling the technology; however, they identified several risks that would need mitigating before approval. To overcome this, a detailed risk mitigation and contingency plan was put in place. This involved critical components that were made available in stock at Arctic Circle, a complete standby system available as a backup in case of system failure and a final failsafe of a conventional semi-hermetic booster system available in case of catastrophic failure of the system. Arctic Circle also agreed to take full responsibility for the design, manufacture, installation, and service of this system which enabled the project’s secrecy while also ensuring trailing the technology was carefully managed. With the plan in place, it was agreed that the field trial could move forward. An independent consultant was introduced to ensure the new scroll technology seamlessly fell into the store’s design; Abbey Design Associates carried this out. The overall proof of concept required some control interface since Emerson wished to apply their Dixell operating platform with a proviso for remote monitoring to be accommodated using Co- op’s preferred RDM equipment through its Technical Services Bureau. Field trials The Co-op engineering team quickly approved the design, and the installation was completed at Co-op Malmesbury Gloucester Road in an 8000 ft 2 food retail outlet which was undergoing significant capital investment at that time. The Wiltshire store is now home to the world’s first field trial, consisting of six compressors, delivering a total of 68 kW of medium temperature load at -8°C saturated suction temperature (SST) and 10 kW of low-temperature load at -32°C SST. A recent analysis by Emerson of the new technology has shown between four and eight per cent seasonal efficiency gains in typical European ambient temperatures.