38% energy saving for 2 Sisters

Like most organisations, 2 Sisters Food Group are coming under increasing pressure to reduce their environmental impact and control costs.

With this in mind engineering staff at the chicken products supplier’s Haughley Park site contacted Excalibur to assess whether it was possible to improve the efficiency of their existing refrigeration.



Excalibur undertook a full survey of the refrigeration, recording all operating parameters which allowed the energy performance of each system to be modelled. Projections showed that following modification energy consumption could be reduced by over 35%.

Initially Roast 95 pack was selected for modification; this comprises 4 Bitzer OSK 7471 screw compressors and an air-cooled 7 fan condenser. The system is used to chill cooked chicken and is a 7 day / week operation.

Excalibur undertook the installation of Liquid Pressure Amplification and Variable Speed Drive to control condenser fans. This allows compressor discharge pressure to be drastically reduced, improving efficiency and reducing mechanical wear. The work was undertaken with no disruption, pre-fabrication being completed during normal working hours and final connections made during a weekend shutdown.

A web-based refrigeration monitoring system was installed to establish the improvements in efficiency, the system being operated in bypass to establish a baseline efficiency before the Excalibur modifications were commissioned. The improved efficiency was immediately clear to see – energy consumption dropped by 38%, giving a return on investment of 15 months and an annual reduction in carbon emissions of 177 tonnes.

“Excalibur installed LPA and inverter control to our Bitzer screw pack, the work was completed to a very high standard with minimum effect to production. Monitoring over the first 12 month period showed a reduction in power consumption of 38%. Several evaporators which had been starved of refrigerant now achieve temperatures where previously they struggled."

“There have been no reliability issues and we are benefiting from a system which is not only energy efficient but also provides improved refrigeration performance.”

Engineering Manager, 2 Sisters Food Group


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