Co-op store proves Copeland CO2 capability

UK: The European roll-out of Emerson’s new Copeland CO2 scroll technology for transcritical booster systems follows a successful 18-month trial at a Co-op supermarket in Malmesbury, Wiltshire.

The latest Emerson solution, announced last week, includes a new range of Copeland CO2 scroll compressors and refrigeration units with smart electronics and new integrated Dynamic Vapour Injection (DVI) technology. Emerson says the technology provides a new solution for CO2 booster systems that enables reduced system complexity and costs while keeping efficiency high in any climate. 

The new generation of CO2 scroll compressors are said to be smaller, lighter, and more cost-efficient than compressors traditionally used for booster systems. In addition, the new integrated Dynamic Vapour Injection (DVI) technology replaces the need for parallel compression and ensures high system efficiency.

Three ranges of scroll compressor are being introduced, covering transcritical (medium temperature) and subcritical (low temperature) operations and offering fixed and variable speed models. 

In addition to its minimal space requirements, it is also said to generate less noise compared with conventional booster systems, a particular in inner-city locations. 

Store selection

Emerson collaborated with a team of engineers from the Co-op and its system partner, Hereford-based Arctic Circle, to select a store for the test installation of the system to verify the efficiency of the innovative system design in combination with a CO2 booster system in the real world. 

A 750m² store in Malmesbury, Wiltshire, was selected for an 18-month trial run. Using information provided on the store, Emerson developed a tailored system featuring six transcritical Copeland CO₂ scroll compressors with optimised drive systems, including variable speeds, control valves and an integrated electronic control system. The required cooling performance was 68kW for normal refrigeration (evaporation at -6°C) and 10kW 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 behaviour and ensuring optimal functionality of several other critical factors. 

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 Emerson 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. 

The CO₂ scroll booster system is controlled and monitored by the specially designed Copeland XC Pro CO₂ scroll controller that is fully compatible with The Coop’s existing building management system (BMS). As the Emerson 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 optimised by the team of engineers during the test phase.  

Performance

Although the 18-month trial spanned the hottest summer in the northern hemisphere (June to August 2020), the system is said to have provided reliable cooling performance from the outset, reaching the level of efficiency achieved by parallel compression systems.

The compact design, which included four CO2 scroll MT compressors with DVI and two CO2 scroll LT compressors with no injection, also led to major reductions in the size and weight of the system. The CO2 scroll booster system weighs around 600kg less (around 60%) than similar products. 

Following the success of the trial, the Co-Operative Group now plans to introduce the new Copeland solution in several additional branches. Knowledge gained from the field test is also expected to provide further operational cost reductions for future installations.

Related stories:

Emerson boost for CO2 scroll technology – 17 September 2021
GERMANY: Emerson has introduced a new range of Copeland CO2 scroll compressors with smart electronics and new integrated Dynamic Vapour Injection (DVI) technology. Read more…