Reliability key to cooling project


12 February 2019
refrigeration ACP ammonia compressor meat processing germany cooling
The ACP with three BITZER OSKA 85 screw compressors
A BITZER ammonia compressor pack (ACP) is delivering fail-safe cooling to a slaughterhouse in Germany.

The EG Schlachthof Bochum plant processes around 350 cattle and 1,500 pigs every day and needed to replace an outdated ammonia system.
Moritz Kruse and his colleague from company 3K Kälte- und Klimatechnik Kruse installed a BITZER ACP and the project team was also tasked with using the new set up and a brine system for production cooling, at the time being operated with refrigerant containing CFC.

Andreas Schulaks, head of industrial refrigeration at BITZER, had approached the 3K company in 2015 to introduce the ACPs. He said: "This was the optimal time for a field test for us. We were certain that our ACP with three BITZER OSKA 85 screw compressors was just the right solution for the slaughterhouse operations based on the set-up.''

The slaughterhouse required an actual cooling capacity of approximately 400 kW. As a result of the planned conversion to non-CFC refrigerant, a decision was also made to equip the processing rooms with a brine system which is cooled by means of the ammonia circuit of the refrigeration system.

Emergency cooler
Moritz Kruse said: "We therefore needed a cooling capacity of around 1,150 kW. The three screw compressors each have a capacity of 400 kW at 2,900 rpm. Thanks to the option to have the compressors turn at 4,200 rpm, we can also ensure that, in the case of a machine malfunction, we have sufficient redundancy, without having to deal with a significant loss in capacity and thus production downtime. So we have access to cooling capacity of 1,548 kW at full machine capacity. The economiser capacity is then 125.8 kW.''

Thanks to the economiser with sliding suction position, operation is also effective in part-load. Moritz Kruse added: "‘We therefore obtain the highest cooling capacity and coefficient of performance possible in full- and part-load. In April 2018, the total power consumption of the system was 67,988.0 kWh for the three BITZER screw compressors, putting the system’s COP/EER at 4.28 at the machine shaft – a figure that can actually be measured.''
The system’s oil cooling also offers heat recovery to preheat the feed water for the heating system: the water is heated to 56°C, with 124.6 kW oil cooler capacity available at full-load. The 3K company has installed an additional emergency cooler on the roof for system reliability.

Reliable partner
Andreas Schulaks said: "‘Our screw compressors are responsible for cooling the pig and cattle cold stores and ensure continuous operation of the ammonia refrigeration system. In the future, they will also provide tempering in the production facility in a secondary circuit. According to plans, the capacity for this circuit will be around 750 kW.''
Moritz Krusesaid "We’ve been working with BITZER since 2016. Andreas Schulaks introduced us to one of the ACP prototypes during a factory tour in summer 2015. BITZER compressors are durable, ultra-reliable machines that are well established in commercial refrigeration. And now that BITZER also offers entire units, we’re more than happy to also use the high-quality screw compressors, which until recently were rarely ever utilised in industrial refrigeration. After all, the fact that we no longer have to construct the units ourselves is an absolute competitive advantage for us.

"The entire project has run smoothly and continues to do so to this day, from the planning and implementation to collaboration following commissioning. All that is a great recommendation for BITZER, who will continue to be a reliable partner well into the future.''
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