Ammonia refrigeration set to expand

The phasing out of R22 – effectively the last of the hydrochloro-fluorocarbon (HCFC) family of gases and one of the most widely used refrigerants industrially – because of the damage it causes to the environment, has led to application of alternative approaches, which meet the needs of the food processing industry while being greener.

While attention initially shifted to hydrofluorocarbons (HFCs), such as R404A, their use has also been restricted because of their high global warming potential (GWP). The new F-Gas Regulations which came into force on January 1 2015, placed restrictions on the use of HFC refrigerants in certain applications.

R404A has a GWP of 3,922 and is therefore in the group of refrigerants with a GWP >2,500, which are most affected by the new regulations. The key parts of the regulations that will have a major impact on the use of R404A are a phasing out of its use, resulting in a ban on its use in new equipment from 2020.

‘Fantastic properties’ ​

Consequently, attention is shifting to the so-called ‘natural’ refrigerant gases, such as ammonia and carbon dioxide. “They have fantastic properties, but they have their issues,”​ Graeme Maidment, professor at London South Bank University’s Centre for Air Conditioning and Refrigeration Research, told our sister title Food Manufacture​ back in 2013. In the same article, Judith Evans, a director at Refrigeration Developments and Testing, agreed that, with its low GWP and relatively high efficiency, ammonia would become the refrigerant gas of choice for many large plants, even though its toxicity remained a concern.

This month (October) new guidance on the use of ammonia refrigerants is being published and this coincides with an ‘Ammonia Summit’ being organised by the Food Storage and Distribution Federation (FSDF), supported by the Institute of Refrigeration. The FSDF’s Technical & Safety Committee (TASC) has been working with the Health & Safety Executive over the past three years or so on the new guidance for the safe management of ammonia refrigeration systems (PM81).

Dangerous ​

They have also been involved with a joint industry project tackling compliance with the 2002 Dangerous Substances and Explosive Atmospheres Regulations.

At the International Institute of Refrigeration’s 24th International Congress of Refrigeration held in Yokohama in August, Star Refrigeration’s group md Dr Andy Pearson delivered a lecture to engineers and researchers on ammonia compliance, titled: ‘Compliance with flammability requirements for ammonia refrigeration systems’.

Pearson noted that ammonia had been used as a refrigerant for over 150 years. While its flammability required careful safety consideration in the design and operation of refrigeration systems, the ignition of ammonia was a very rare occurrence and virtually unknown in systems which complied with European Standards requirements, he said.