Carbon dioxide can replace liquid nitrogen for freezing

Refrigeration specialist Starfrost has developed a way of using carbon dioxide to freeze seafood products that previously could only be frozen using liquid nitrogen.

It has built two pilot systems that combine carbon dioxide refrigerant with low temperature, high velocity freezing techniques.

Both are non-cryogenic mechanical systems and operate at lower temperatures than the -32°C of conventional freezers.

One system is a contact freezer in which the product is placed on a smooth metal plate containing refrigerated pipes. Tests have shown that soft and wet seafood such as scallops are highly suited to this freezing process which leaves no belt marks. The other pilot system is a low temperature, high velocity impingement wind tunnel.

The pilot systems have been successfully tested on large, shell-on shrimps, which require extremely fast freezing. In the past only cryogenic freezing with liquid nitrogen was suitable.

The technology also offers users the potential to recover waste heat and energy from the system. The hot water recovered can then be used as high grade hot water for cooking, cleaning or process heating.

CONTACT Starfrost TEL 01506 562206