Kenyan fish processing facility upgrades from R22 to ammonia
East Africa Sea Foods (EASF), a fish processing facility in Kenya, recently replaced its aging R22 refrigeration system with a two-stage ammonia system.
EASF had been using a HCFC-22 refrigeration system since 1990 . In compliance with the Montreal Protocol on Substances that Deplete the Ozone Layer, developing countries must phase out HCFCs by 2030. Therefore, an upgrade was necessary.
In 11 months, the company has completely revamped is refrigeration system, with new compressor sets, evaporative condenser, piping, valves and electrical main control panels.
EASF management reports that reasons that motivated the transition from R22 to ammonia were the following: environmental responsibility, energy management and cost.
Ammonia has no GWP and no ODP. It is thus not restricted under the F-gas regulation. In comparison, R22 is an HCFC with a GWP (Global Warming Potential) of 1,780 and an ODP (Ozone Depleting Potential) of 0.034. The company had considered using R507 because of its coefficient of performance (COP), but R507 is a HFC mixture with a GWP of 3,985.
Ammonia requires less energy to produce refrigeration cooling capacity compared to other common refrigerants.
GEA, the system supplier, had calculated that using R507 on the existing compressors would result in an average compressor/ shaft power COP of 1.42. Meanwhile, using ammonia, the compressor/shaft power COP is 1.68.
They had also investigated two other options: using a screw compressor on R507 which yielded a compressor/ shaft power COP of 1.04; or using a multiplex rack of 11 commercial compressors which yielded a combined compressor/shaft power COP of 1.07.
Ammonia is cheaper and more easily available than other refrigerants the company had considered.
Despite its advantages, ammonia also presents with potential safety hazards. Namely, it is flammable and toxic in large concentrations .
The system installed by EASF has a total ammonia charge of approximately 1,400kg. The company has designed a comprehensive plan to ensure the safety of its new facility. Their safety plan included risk-assessment analysis, providing staff with safety equipment and training all staff on safety procedures in the event of an ammonia leak.
 Hafner A., The advantages of natural working fluids, Proceedings of the 25th IIR International Congress of Refrigeration: Montreal , Canada, August 24-30, 2019. This paper can be downloaded in FRIDOC database (free of charge for IIR members) by using this link.