Ammonia in industrial refrigeration
State-of-the-art components for ammonia
Environmental concerns and new regulation are forcing everyone to take a serious look at natural refrigerants like ammonia (NH3), CO2, and others as long-term alternatives for industrial refrigeration. As anyone involved in food preservation and industrial processing plants already knows, ammonia is an ideal refrigerant to its unmatched thermodynamic properties.
Having passed the test of time as one of the best refrigerants available, ammonia is now being considered for applications that were previously unthinkable. As a leader in ammonia refrigeration components—including manual, mechanical, and electrical valves — Danfoss is constantly developing safe and energy-efficient components for ammonia refrigeration, particularly in industrial refrigeration.
While ammonia is not a universal refrigerant—mainly suitable for industrial and heavy commercial applications—and its toxicity, flammability, and material compatibility must be taken into account during system design, there is a huge global population of ammonia systems where those challenges have successfully been dealt with.
Ammonia offers a wealth of benefits for industrial refrigeration
With CFCs and other synthetic phased-out, many in the HVACR industry have looked back to natural refrigerants, including ammonia, as replacements. Ammonia has a number of benefits, which have been proven the past hundred-plus years.
Ammonia is one of the most efficient refrigerants available, with applications ranging from high to low temperature. With the industry focusing more and more on energy efficiency, ammonia systems are a safe and sustainable choice for the future. Typically, a flooded ammonia system is 15–20% more efficient than an equivalent DX R-404A counterpart. Recent developments in combining ammonia with CO2 have contributed to further increases in efficiency. Ammonia/CO2 cascade systems are extremely efficient for low and very low temperature applications, while ammonia/CO2 brine systems are around 20% more efficient than traditional brine systems.
Ammonia is one of the most environmentally friendly refrigerants available. A natural refrigerant, ammonia has both a GWP (global warming potential) and an ODP (ozone depletion potential) score of zero.
While ammonia is a toxic refrigerant and is flammable at certain concentrations, all ammonia systems have to be designed with safety in mind. And unlike most refrigerants, ammonia has a characteristic odor that can easily be smelled even at low concentrations, providing a clear warning in case of even minor leaks. If reducing the charge is necessary, combining ammonia with CO2 (in either cascade or brine systems) provides a viable option.
In both vapor and liquid phases, ammonia requires smaller pipe diameters than most synthetic refrigerants, reducing initial system costs.
Ammonia has better heat transfer properties than most synthetic refrigerants, allowing for a smaller heat transfer area and lowering plant construction costs. And as the heat transfer properties also improve the system's thermodynamic efficiency, operating costs of the system are also lowered.
In many countries, the per pound cost of ammonia is considerably lower than that of hydrofluorocarbons (HFCs). This advantage is multiplied by the fact that ammonia has a lower density in liquid phase. Furthermore, as any ammonia leaks will be detected very quickly due to the odor, the chance of any potential refrigerant loss is very low.
Products for ammonia
See all our products developed for industrial refrigeration and ammonia.
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History of Ammonia as a Refrigerant
Ammonia was first used as a refrigerant in 1876 in a vapor compression machine built by Carl Von Linde. Other refrigerants like carbon dioxide (CO2) and sulfur dioxide (SO2) were also commonly used until the 1920s.
Chlorofluorocarbons (CFCs) hit the US in the 1920s, swinging the pendulum in favor of synthetic refrigerants; compared to other refrigerants used at the time, CFCs were considered harmless and extremely stable. CFC refrigerants were promoted as safety refrigerants, resulting in high demand. Due to the success of CFCs, ammonia was looked upon less favorably, though it was still used, especially in food preservation and large industrial installations.
In the 1980s, the harmful effects of CFC refrigerants became apparent and it became generally accepted that CFCs were contributing to global warming and the depletion of the ozone layer. The result was the Montreal Protocol (1987), where nearly all countries agreed to phaseout CFCs in a timely manner. Later revisions to the Montreal Protocol and the later adoption of the Kyoto Protocol accelerated the phaseout schedule.
Today, with CFCs and many other synthetic refrigerants being no longer viable options, ammonia's popularity is growing. Once seen as a less desirable, potentially dangerous choice, today's ammonia refrigeration systems are rigorously engineered to maintain high efficiency and maximum safety.