Case studies

Prosper de Mulder

Planning / Implementation / Main components

Star Refrigeration Ltd.


Carbon dioxide (CO2), secondary refrigerant Ammonia (NH3)

System start-up


Prosper de Mulder, the UK's largest pet food processor, had a requirement for an efficient plate freezing system to replace the old R-22 system for their pet food production facility in Doncaster, England.


Replacement of the old refrigeration plant which used R-22 with a non ozone depleting refrigerant which would not be subject to impending F-gas regulations.


Installation of an environmentally friendly and highly efficient plate freezer system using carbon dioxide as the refrigerant with ammonia condensers.

Technical data:


Type of facility

Vertical plate freezer system



Secondary Refrigerant


No. of refrigeration compressors


Refrigerant temperature

CO2 -50 ºC, NH3 -40 ºC

Refrigerating capacity

1,000 kW

Main components

Screw compressors, surge drum/pump set, 16 plate freezers

Special features / Comments

The main environmental benefit is the low energy consump-tion of this system. The combination of CO2 with pressurized liquid defrost for a plate freezing system is a world first. Freezing times are 75 % of the traditional system and the system is running more efficiently at far lower temperatures without causing excessive power consumption.


Star Refrigeration Ltd.
David Blackhurst
Thornliebank Industrial Estate
Glasgow G46 8JW, UK
Phone: +44 (0)141 638 7916
Fax: +44 (0)141 638 8111
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