Ammonia is a natural refrigerant that has an ozone depletion potential (ODP) of zero and a global warming potential (GWP) of less than one. Ammonia systems can be designed to be more compact than HFC systems of the same capacity. Piping and heat exchangers can be smaller because of the efficient refrigeration properties of ammonia and its low charge. Field-erected ammonia refrigeration systems usually use evaporative condensing. With ammonia as a refrigerant, lubricant management is simplified because ammonia is not miscible with most industrial refrigeration lubricants, and oil return is effective and easy to manage in properly designed systems.

Industrial refrigeration contractors are familiar with the codes and regulations that apply to ammonia refrigeration systems such as ASHRAE 15 and ANSI/IIAR codes. OSHA regulations that describe safe plant operation, maintenance, documentation and incident reporting only apply to ammonia plants with more than 10,000 lb of ammonia.

Ammonia is one refrigerant that is here to stay. Ammonia will not be phased out as many halocarbon refrigerants have. While chemical companies continue to create new molecules for refrigerant applications and many countries are looking at limiting even the newer HFC refrigerants, natural refrigerants remain a good choice for today and the future.

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