End-users are often faced with a dilemma when they have to choose between refrigeration contractors, especially if there is an option between Freon and Ammonia. When comparing refrigeration systems the difference in COP is the most important consideration. The Coefficient of Performance (COP) is a useful measurement of the efficiency of refrigeration systems. The COP based on the amount of power consumed by a system, compared to the output of that system. The higher the COP, the more efficient the system. When designing a refrigeration system and choosing a refrigerant, few other factors should be taken into account. The first consideration is the size of the installation both in required refrigeration capacity and the dimensions of the facility. For a logistics company that caters for small multi-temperature loads in a business park with a capacity to handle 400 pallets, an ammonia system will be an expensive option. However for large cold storage facilities consisting of several cold stores in the 1500 m2 range operating at -25oC, centralised ammonia systems have always been the preferred option. Direct-expansion (DX) Freon systems when compared with pumped ammonia systems have the tendency to dehydrate fresh product whether it is meat, fruit or vegetables. To ensure the complete evaporation of the refrigerant vapour / gas, it’s allowed to be superheated in order to protect the compressors from liquid carryover. In some industries product weight losses is absolute critical and the payback of the refrigeration system is not only related to the energy consumption or initial capital layout. One such an example is weight losses occurred during carcass chilling at large red meat abattoirs. For the storage of decisions fruit (apples and pears) in Controlled Atmosphere (CA) stores in the Western Cape stores ammonia systems have always the preferred solution. Ammonia is a natural refrigerant with a zero ozone depletion potential (ODP) and global warming potential (GWP). It has been considered to be an excellent choice of refrigerant for industrial applications for over 150 years. However, ammonia is toxic and besides it is also flammable and requires careful safety consideration in the design and operation of refrigeration systems (Maurice Young). To mitigate the risks and to improve safety; the ammonia refrigeration industry and installations in South Africa are well regulated. For more information please contact Shaun Kleb on +27 21 555 9000.
