Back in 2017, the British supermarket chain The Co-Operative Group (The Coop) committed to the gradual replacement of the HFC based refrigeration systems in its retail stores with CO₂ refrigerants. As a result, innovative Copeland CO₂ scroll technology for transcritical booster systems was tested as part of an 18-month field test between The Coop and their Plant Manufacturing partner Arctic Circle Ltd to great success.
The latest solution pioneered by Copeland proved a major hit in every respect due to its high efficiency in the absence of the standard, unavoidably complex system design. In addition to its minimal space requirements, it also generates less noise compared with conventional booster systems, which offers numerous benefits, particularly in inner-city locations. The Co-Operative Group now plans to introduce the new Copeland solution in several additional branches following on from the success of the trial run.
The Coop is one of the largest supermarket chains in the United Kingdom, with over 2,500 stores across the UK. In response to growing environmental consciousness and the steady phase-out of F-gases since 2015, the company found itself looking for a way to gradually convert the refrigeration systems in its stores to future-proof, sustainable technology based on the natural refrigerant CO₂. The new system needed to offer significant benefits, not only in terms of efficiency and reliability, but also in terms of certain underlying factors linked to the overwhelmingly inner-city locations of the branches. In order to ensure optimal use of the expensive yet minimal available floor space in comparison to the existing system, the new cooling system needed to take up far less space and weighs considerably less. Another must-have on the list of requirements was significantly reduced noise emissions to avoid disturbing the neighbors with operating noise.
Copeland collaborated with a team of engineers from The Coop and its system partner Arctic Circle Ltd to select a store for the test installation of the system to verify the efficiency of the innovative system design in combination with a R744 booster system in the real world. They quickly found the perfect candidate with a store located in Malmesbury featuring 750 square meters of floor space. Using information provided on the store, Copeland developed a tailored system concept for an 18-month trial run. In addition to other components, the new system featured six transcritical Copeland CO₂ scroll compressors with optimized drive systems, including variable speeds, control valves and an integrated electronic control system. The required cooling performance was 68 kW for normal refrigeration (evaporation at -6°C) and 10 kW for deep freezing (evaporation at -28°C).
At the customer’s request, the system was installed and commissioned by a joint expert team. These tasks included a review of the installation site, adjusting the refrigeration units’ superheat settings, monitoring the oil return behavior and ensuring optimal functionality of several other critical factors. In terms of software, the control and monitoring system of the CO₂ scroll solution needed to be integrated into the existing building management system (BMS) used to manage all stores owned by The Co-Operative Group in the UK. As the Copeland control unit is fully compatible with the BMS, this connection could be implemented without an additional gateway, saving both time and money. The system was continually optimized by the team of engineers during the test phase. Knowledge gained from the field test will further reduce the operational costs for future installations.
Impressive endurance: During the trial run that spanned 18 months in total, the system provided reliable cooling performance from the word go during the hottest summer in the northern hemisphere (June to August 2020) since records began.
Low Noise Level and Space Savings
“With lower noise level than reciprocating compressors, this brand-new CO2 scroll technology ensures that the most stringent noise levels can be achieved. With so many urban store locations, this is especially important for the Coop. In fact, the noise level of the running system was so low that I asked ‘is the unit actually running?’ when first entering the plant enclosure. The Coop is extremely proud to have been able to facilitate this enterprising technology, which is probably the most well-kept secret in recent times when it comes to new refrigeration solutions design. The Plant has performed admirably during the past 18 months and to now have the Factory Manufactured versions is a significant step forward from the original prototype development. The compressors are very compact and offer a smaller footprint plant design as available space is at a real premium for The Coop".
Adrian Crowther, Design & Standards Manager (Refrigeration), The Co-Operative Group
One of the key features of the new system is the significantly slimmer design of the refrigerant circuit. The innovative technologies employed in the new system have allowed Copeland to forget the use of numerous additional components often used to increase efficiency in CO₂ systems, such as parallel compressors to recirculate the flash-gas. During the trial run in Malmesbury, perfectly matched components enabled the Copeland CO₂ scroll booster system to reach the level of efficiency achieved by parallel compression systems.
The compact design has also led to major reductions in the size and weight of the system. The CO₂ scroll booster system weighs around 60 percent less than similar products. In total, it weighs around 600 kg less than a comparable solution using conventional technology. The space-saving construction and low weight facilitate installation where space is limited, such as on the roof, which is often the only option at many stores. An added plus: The new system is much quieter than the refrigeration system with reciprocating compressors previously installed at the Malmesbury store.
The new Copeland CO₂ scroll technological innovation with Dynamic Vapor Injection (DVI) for booster systems boasts high efficiency, compact dimensions, low weight and significantly reduced noise emissions. As a result, the advantages and potential offered by CO₂ based refrigeration systems can now be efficiently utilized in small and medium-sized areas. The system makes a significant contribution to the increased sustainability, competitiveness, and future viability of supermarket operators. Based on the result of the 18-month trial run, The Co-Operative Group has decided to gradually install the Copeland CO₂ scroll booster system at several other stores.
Project
The Co-operative Group – CO2 refrigeration system for small and medium-sized retail applications
Achievement
Trial installation met with great response
System
Copeland CO2 scroll booster system – technical details
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