Ammonia has long been used as a refrigerant for industrial applications. The engineering and servicing requirements are well established to deal with its high toxicity and low flammability. Technical developments are extending the applications for ammonia, for example, low-charge packaged liquid chillers for use in air conditioning. Ammonia cannot be used with copper or copper alloys, so refrigerant piping and components have to be steel or aluminium. This may present difficulties for the air-conditioning market where copper has been the base material for piping and plant. One property that is unique to ammonia compared to all other refrigerants is that it is less dense than air, so a leakage of ammonia results in it rising upwards and into the atmosphere. If the plant is outside or on the roof of a building, the escaping ammonia can drift away without harming occupants. Ammonia can be detected by its characteristic odour at very low concentrations, and this acts as an early warning signal. The safety aspects of ammonia plants are well documented, and there is reason to expect a sustained increase in the use of ammonia as a refrigerant.
Posted in Refrigeration and Air Conditioning