Energy costs for the previous cooling system were £146,000 a year, compared with an estimated £61,000 for the new Bitzer ACP pack, saving over £80,000 a year in running costs – a reduction of nearly 60% – and delivering substantial savings in carbon emissions.

The project is part of a site-wide energy efficiency programme designed to reduce power consumption and carbon emissions.

Demeva Refrigeration Limited, based in Formby, Merseyside, specified a 707kW Bitzer Ammonia Compressor Pack (ACP), powered by high performance screw compressors, to replace an end-of-life ammonia system by another manufacturer that had been in service for 20 years.

The existing ammonia charge was retained for use in the new system, further supporting the economic case for the upgrade.

The new Bitzer ACP system provides primary cooling at an evaporating temperature of -9°C for the site's secondary glycol circuit, serving cold stores at 2°C and air handling units at 8°C within the processing facility.

Timing on the project was critical due to the need to ensure continuity of cooling at the production facility. This was assisted by being able to run the system’s second compressor during the switchover.

A logistical challenge was removing the old system and locating the new pack in position in the plant room. This required relatively straightforward modifications to pipework to connect the ACP pack to the central glycol system, followed by electrical connection.

'It was the first Bitzer ACP pack we have installed,' said Dean Rawling, Demeva director. 'Having assessed the technology currently available on the market, we believeBitzer 's ACP system is the most efficient ammonia refrigeration solution available. Plus, importantly, it has the added safety benefit of being built and tested in pristine factory conditions by Bitzer .'

In the run-up to the replacement, the project leads from Demeva and Pilgrim UK visited Bitzer's manufacturing and R&D facility in Stuttgart, Germany, to see first-hand the production process.

Rawling said: 'Bitzer's factory systems and technical support are second to none, and it gave the customer confidence that the proposed ammonia solution was designed, built and tested in a world-class facility by people with deep experience of the technology and its application.'

A key target for the project was to achieve pay-back on investment within one to one-and-a-half years. This was achieved as a result of the significant energy savings.

Once the pack was installed, Bitzer engineers from Germany attended site to assist with commissioning and ensure the plant was optimised to deliver the anticipated savings.

Adrian Spencer, Demeva's refrigeration manager, said: 'The support from Bitzer throughout the project was first class, from first contact to final handover. Bitzer UK's James Graham was a key point of contact and provided excellent support throughout.'

Other energy saving measures implemented at the site include replacement of the evaporative condenser for the refrigeration pack, installation of modern high efficiency glycol pumps on the secondary circuit, and a new Building Energy Management System to provide site-wide monitoring.

Neil George, Pilgrim UK’s engineering manager, said: 'Responsible energy use is a major area of focus for our business. We are constantly looking for opportunities to improve energy efficiency and reduce emissions. The Bitzer ACP pack, combined with the other efficiency measures implemented by Demeva Refrigeration, will significantly reduce power consumption at Bromborough and deliver significant savings in carbon emissions.'

The project is part of a multi-million pound investment programme by Pilgrim UK to further enhance the sustainability of its operations, with the aim achieving net zero by 2030.

Alongside upgrades to refrigeration plant, this includes replacing gas boilers with heat pumps and completing the transition to LED lighting across its sites.

The company already has local solar and wind projects at many locations and is expanding these to the remainder of its manufacturing plants across the country, helping to reduce carbon emissions by an estimated 11,000 tonnes a year.

Bitzer's ACP range has been designed to meet the requirement for very high efficiency cooling for industrial applications with a zero Global Warming Potential (GWP) refrigerant.

In addition to its exceptional part-load efficiency, it offers outstanding resilience, with a back-up compressor in the unlikely event of a failure, and rapid commissioning due to its plug-and-play design.

Kevin Glass, managing director of Bitzer UK, said: “Ammonia refrigeration systems have traditionally been built as one-offs, often in less than ideal conditions. Bitzer is able to build ACP units in a high quality factory environment, ensuring the highest possible system integrity, absolutely essential when working with ammonia.”

He added: “The modular design means that contractors can quickly connect up ACP units on site with a few simple pipework and electrical connections. This dramatically speeds up with process of installation and commissioning.”

ACP packs are based on compact Bitzer screw compressors, which result in a smaller footprint than equivalent-capacity reciprocating compressors.

In addition to the inherent efficiency of screw compressors, the speed of the lead compressor is controlled by an integrated Variable Speed Drive (VSD), which significantly increases part-load efficiency and enables soft-start, important on sites where power headroom is limited.

A further benefit for end users is that the screw compressors used on ACP have much longer maintenance intervals than reciprocating compressors, further reducing the cost of ownership over the plant's life-time.