Due to its phaseout, an alphabet soup of replacement refrigerants has been developed to replace R-22 in existing chillers. However, most of these alternatives have drawbacks. Some replacements severely penalize the performance of the chiller, while others have significant glide—and all have higher global warming potential than ammonia. And though these refrigerants may not be on the Environmental Protection Agency’s (EPA) phaseout list yet, they have the potential to be. As new chillers rise to replace the old, ammonia is one refrigerant that has become an effective alternative.
Ammonia: a perfect refrigerant for chillers
Ammonia has been the mainstream refrigerant of choice in the food and beverage industry for 100 years, but this business segment represents a fairly small portion of the overall refrigeration industry. The single largest business segment is HVAC. While ammonia cannot be used directly, it is a perfect fit for chillers.
More and more, the HVAC industry is turning toward ammonia as a viable option in chillers. In Europe, a significant portion of water chillers use ammonia refrigeration.
Low-charge refrigerated packaged equipment maximize ammonia’s benefits, minimizing the charge
Low-charge packaged chillers take advantage of the excellent thermodynamic properties of ammonia while minimizing the charge, and, thus, the risk. Some of these chillers only use one pound of ammonia per ton of refrigeration (TR).
Refrigerated packaged equipment offer benefits such as:
- Shorter lead times
- Less onsite construction
- Factory built for better quality control
- Optional machine room enclosures
The low-charge packaged chillers have been developed in two main configurations: air-cooled and water-cooled. In certain conditions, evaporative cooled packages are also a possibility.
Air-cooled ammonia chillers
Packaged air-cooled ammonia chillers have been entering the U.S. market from Europe, potentially serving as a major replacement for smaller commercial chillers used in HVAC.
Just like the Freon packages, these packaged air-cooled chillers are compact, completely self-contained and are a true “plug-and-play” configuration. These units consist of:
- Rotary screw compressors
- Plate and shell chillers
- Air-cooled condensers
Water-cooled ammonia chillers
The water-cooled solutions range reaches up to 1,200 TR, using semi-welded plates and frame heat exchangers for both the chiller and condenser. These packages require:
- A machine room
- Cooling tower
- Pumps
Their size, electrical loads and efficiency make them an excellent replacement for R-22 chillers.
The water-cooled solutions can be made much larger, with individual units over 1,200 TR. Multiple units can be combined for larger applications. These units consist of:
- Rotary screw compressors
- Plate and frame or plate and shell evaporators
- Plate and frame or plate and shell condensers
- Cooling tower
Their size, electrical loads and efficiency make them an excellent replacement for R-22 chillers.
