Energy-efficient refrigeration

REFRIGERATION technology is an inherent and essential part of the food processing industry, whether for meat, beer or vegetables, beginning with maintaining the quality of raw materials to freezing processes and all the way to cooling chambers for finished products. Many refrigeration solutions need to be customised to suit specific needs of the processor, manufacturing parameters and even the environment.

GEA Refrigeration Technologies design and implement such solutions using components that best conform to customer requirements. Two recent projects involved ice water production (approx 1°C) reliably and cost-effectively for a dairy co-operative and a refrigeration system for a fruit and vegetable storage facility in an area with 300 days of sunshine. 

Dairy reduces energy cost
When a dairy company expanded production capacities to meet growing demand at home and abroad with its many dairy products, it also modernised its refrigeration technology in two of its seven facilities. Mlekpol, the largest Polish dairy co-operative and one of the country's leading producers of UHT milk, required a refrigeration system that would produce ice water (approx. 1°C) reliably and costeffectively. In upgrading the refrigeration plant, the most important criteria were maximum energy efficiency and optimisation during partial-load operation.

Mlekpol had already gained positive experience with systems from GEA Refrigeration Technologies and as a result, the co-operative also awarded these contracts to GEA refrigeration experts. On the basis of optimised partial-load system behaviour, the newly marketed piston compressors from the GEA Grasso V 1100 range were chosen to replace the old systems in both plants. To cover the requirement of approximately 3 to 4 MW cooling duty, the dairy installed four V 1100 units in Grajewo, and five in Mr?gowo. These compressors, with ammonia refrigerant, each provide up to 830 kW cooling output.

Since milk production does not always need maximum refrigeration output, these piston compressors were outfitted with frequency converters – as were the fans for the condensers and the pumps for the ice water. The GEA Grasso control system automatically assures efficient operation of the refrigerating compressors. As a result, intervention into the control system is necessary only for new programming or in case of irregularities during operation. In this context, the system is connected via a virtual private network (VPN) to GEA Service. Alarm reports are additionally issued to the smart phones of the Mlekpol team of technicians and to the monitors of the Technical Department.

The fully automated control system simplifies plant operations for the staff. Technicians now need to enter the refrigeration centre only for inspection purposes, and otherwise remain on call for emergencies. Normal operations are automatically controlled, depending on the respective requirements and on the basis of energy and component-wear optimisation. Optimal utilisation of the power rates also takes place automatically. Toward this objective, the control system uses two different operational settings based on power prices. When the power price is favourable, the system will fill the ice banks of the plant, and only after maximum ice storage capacity is reached do the compressors go over into normal operational mode. When power prices are high, however, refrigeration is provided primarily from the ice banks before the compressors are called on to cover cooling requirements. In this way, the power costs (which are already favourable) can be reduced even more.

After being in operation for about eight months, the compressors of the GEA Grasso V range have impressively demonstrated their efficiency. The upgraded refrigerationMiesten kengät laajasta valikoimasta