CA Warehouse Mansfields

The British fruit grower Mansfields stores apples and cherries in a controlled atmosphere so that they will be available in top quality all year round regardless of when they were picked. For refrigeration the family company uses a secondary refrigerant system with propene (R 1270). Re-phridge provided the specialist support for the safe application of the hydrocarbon refrigerant.

Requirement

Mansfields wanted an efficient, HFC-free refrigeration system for the warehouse in Chartham near Canterbury.

Solution

The refrigeration experts International Controlled Atmosphere Storage and SRS Frigadon designed a propane secondary refrigerant system with an output of 1,150 kW. Five air-cooled factory-assembled packages charged with altogether 90 kg propene provide refrigerating energy for the secondary circuit at a temperature of -9°C. A brine mixture of water and salt is used as the secondary refrigerant. The circuit is filled with 30,000 l and works at an operating pressure of only 1.5 bar to cool the heat transfer fluid down to -3°C. The brine is pumped to the 36 controlled atmosphere cold storage rooms which are kept at a constant air temperature of -0.5°C and 1.5°C. The secondary refrigerant also cools the preparation and loading areas. The system design minimises the quantity of refrigerant and guarantees an ESEER (European Seasonal Energy Efficiency Ratio) of more than 4.2, although based on local conditions the real seasonal cooling COP (coefficient of performance) is around 6.