Ammonia is an alkaline, colourless chemical compound, produced both naturally and as a by-product of numerous man-made reactive processes. Large amounts of naturally occurring ammonia gas come from livestock animals, soil surfaces and even the human body. Manmade processes that emit ammonia to the atmosphere include fuel combustion processes and sewage treatment plants.
What are the overall advantages of using ammonia as a refrigerant?
As a refrigerant, ammonia offers four distinct advantages over other commonly used industrial refrigerants. First, ammonia has superior thermodynamic qualities, as a result ammonia refrigeration systems use less energy input. Second, it’s a very cost-effective refrigerant. Third, ammonia is environmentally compatible. It does not deplete the ozone layer and does not contribute to global warming. Fourth, ammonia's recognizable smell is its greatest safety asset. Unlike most other industrial refrigerants that have no smell, ammonia refrigeration has a proven safety record in part because leaks are not likely to escape detection.
- THERMODYNAMIC CHARACTERISTICS
Ammonia has good energy efficiency; high latent heat and therefore less refrigerant charge; it can withdraw renewable energy from the air even at very low temperatures, thus avoiding electrical aids or back-ups.
- ECONOMIC ADVANTAGES
Ammonia is one of the most common compounds found in nature. It is well recognized as the basis for household cleaning products, and also has many agricultural, industrial and commercial uses. The cost of ammonia is low, significantly less than competitive industrial refrigerants and less ammonia is also generally required to do the job than other industrial refrigerants.
- ENVIRONMENTAL ADVANTAGES
Ammonia is not a contributor to ozone depletion, greenhouse effect or global warming. Thus, it is an environmentally friendly refrigerant. Ammonia has no cumulative effects on the environment and a very limited (a few days) atmospheric lifetime. It is even used to reduce harmful stack gas emissions by injection into boiler and gas turbine exhaust streams. Ammonia may be released to the atmosphere by sources such as decaying organic matter, animal excreta, fertilization of soil, burning of coal, wood, etc. and by volcanic eruptions.
Ammonia is a natural refrigerant. It is not a halocarbon like many of the synthetic refrigerants on the market which, on the contrary, reduces the ozone layer's effectiveness when they are released in the atmosphere. With increased regulation being placed upon the use of chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) based refrigerants, and the pending phase-out of CFCs and HCFCs, alternative refrigerants for use in existing refrigeration systems are actively being investigated. Ammonia represents a competitive and environmental-friendly solution.
- SAFETY STANDARDS
All refrigerating systems require risk assessment and ammonia systems are not exceptions; every refrigeration system is required by codes, which are effective, mature and constantly updated and revised, to have safety relief valves to protect the system and its pressure vessels from over-pressurization and possible failure. The most common and preferred method of release is by venting of the vapour from the relief valves to the atmosphere. Moreover, the self-alarming property of ammonia (its smell) is immediately recognizable. Thus, small leaks are repaired quickly and not neglected or dismissed as insignificant.