High Growth For Low Charge

The pace of adoption of low-charge and packaged systems continues to increase as government regulations, sustainability initiatives, safety precautions, and technology advance.

“There has been a drive to reduce refrigerant charge in all refrigeration,” said John Collins, industrial sales manager for Zero Zone. “The synthetic refrigerants containing HFC compounds are being regulated. Current and proposed regulations set definite limits which are driving system design for those types of systems and driving low-charge systems and more packaged unitary equipment because they’re trying to get the charge down.”

The U.S. Environmental Protection Agency has been given statutory authority to move forward with phasing down hydrofluorocarbons as part of the American Innovation and Manufacturing Act (AIM), which has impacted the refrigerant industry.

The AIM Act and current EPA proposals could place a hard number of pounds on the refrigerant requirements. “Under the proposed regulations in California, if you have more than 50 pounds and it is higher than a certain global warming potential, you can’t use it for new systems,” Collins said. “There are ranges of GWP limits based on the application.”

Those limits are central to growth. “The more stringent they are, the more end users will gravitate towards natural or other ‘future proof’ solutions,” said Glenn Barrett, engineering manager at DC Engineering. “Down the road, natural refrigerants may end up being the only future-proof solution.”

Europe has also placed regulations on synthetic refrigerants, which is adding to the adoption of low-charge and package systems technologies, but so is consumer and stakeholder awareness. Corporate sustainability statements are being scrutinized by employees and board members, explained Dave Fauser, director of sales for CIMCO Refrigeration.

Safety is also driving the growth of low-charge systems, especially for ammonia. “When the amount of ammonia in a system is small, the risks of a refrigerant release with offsite impacts become very low. This is driving a trend toward low-charge ammonia systems in the refrigeration industry today,” Collins said.

For CO2, reducing charge helps manage the refrigerant and reduces risk if there is a release within the system. “Even with an A1 refrigerant, there are hazards. CO2 is heavier than oxygen. If CO2 is released and settles, it displaces the oxygen in the area. It is colorless and odorless. So there isn’t a realization that it is there until there is a physical reaction,” Collins said.


There are more options than ever in packaged equipment, and package and low-charge systems are growing alongside traditional installations and natural refrigerants.

“The growth in the overall market has been very strong the last few years,” Liebendorfer said, adding that the one segment that packaged systems are displacing field-erected systems is the cold storage industry, where designers, builders, and owners have come to recognize the benefits of eliminating the central plant machinery room. “As a sign of this, commercial packaged CO2 transcritical systems have recently ‘jumped out’ of its strong growth in supermarket applications and into the cold storage market.”

Liebendorfer said slower growth eight years ago is being overtaken by much faster adoption in the last few years for industrial low charge ammonia packages. “This seems to indicate the market is coming into a tipping point,” he said. “The largest growth is in the cold storage market where they are a great fit, but other markets have been steadily increasing.”

Several factors are driving growth, including strong growth in the overall frozen food markets and construction markets requiring new refrigeration systems and interest in reducing the quantity of ammonia at a facility and staying below regulated thresholds.

Other active market segments include food and beverage processing, the chemical industry, and dairy. “Ammonia is being inquired about for HVAC (chillers) and non-traditional industrial applications, while CO2 is experiencing even greater interest in the commercial refrigeration and HVAC markets,” Liebendorfer said.

The recreational market is also embracing the systems. “For our ice rink side, almost everything is low-charge design,” Fauser said, adding that customers in all sectors want to lower risk, lower cost and increase efficiency in all sectors.

Glenn Barrett, engineering manager for DC Engineering, said, historically, natural refrigerants were not used in supermarkets, but that is changing. He added that the use of low-charged packaged systems, commonly called “micro-distributed” in supermarkets, has grown tremendously over the past two to three years.

“These systems typically use R290 (propane) or an HFC/HFO blend as the refrigerant with charge sizes from 150 grams to 20 pounds of refrigerant per appliance. A typical HFC compressor rack averages between 700 and 2,000 pounds,” Barrett said. “They are typically deployed with a hydronic loop as a source to reject heat from the evaporators and compressors and have sophisticate controls and alarm features.”

Ammonia, especially in secondary chiller systems, is being used in nonindustrial applications. “I don’t see that going away or reducing, but we’ll be seeing some other options,” Collins said. “CO2 is taking more and more market share in filling those needs.”

Collins said he is seeing more and more packaged units coming to the industrial sector due to the need to streamline the installation process and have a more repeatable process that can be used by technicians. He said there has also been a move towards more secondary chiller systems circulating chilled glycol.

In more traditional pumped ammonia systems, there could be 20 pounds of refrigerant per ton. “With other designs, we see large central plant installations with charges in the range of 10 pounds per ton. For chiller systems and package systems, charges are typically in the range of two to five pounds per ton; potentially even lower. It is a dramatic difference in how you design the system,” he explained.

The next step is unitary type of equipment, using similar strategies on the system design side, with units of 10, 50, and 100 tons capacity. “You can reduce the amount of field pipe, so you don’t have a lot of refrigerant in large pipes for hundreds and hundreds of feet,” Collins said. “Right there, you’re reducing the charge significantly.

Fauser added that end-users don’t have to take an all-or-nothing approach to low-charge. For example, although low-charge packaged systems may not be feasible for massive food and beverage plants, low-charge technology can still be incorporated into the design. “There is a solution that works for everything, and it is nice to have those options.”

Barrett said he could see the adoption of A2L refrigerants for many applications. Still, he wouldn’t be surprised if the added costs to implement the mildly flammable A2L refrigerants will lower or eliminate the cost premium end users currently pay for natural refrigerant solutions.

“If the EPA regulations are implemented as proposed, some micro-distributed designs may need to migrate to a natural refrigerant, or an A2L, to remain under the GWP thresholds,” Barrett said. “Although natural refrigerant solutions can carry a first cost premium when compared to synthetic refrigerant systems, the cost difference between a natural refrigerant system and an A2L system has not been determined due to unknowns regarding how the safety and leak detection requirements will affect equipment and construction costs.”


Technology has continued to evolve and improve, making low-charge systems more appealing. “Historically, engineers and maintenance professionals only used the small condensing units as a last resort or to fill a very small need,” Barrett said. “When compared to typical HFC parallel compressor racks, condensing units were considered to be poorly controlled and energy ‘hogs.’ Maintenance costs could also be significantly higher and overall reliability is still an outstanding question.”

Variable capacity compressors, the ability to adjust the discharge pressure according to ambient or loop temperature, electronic expansion valves, and case controllers are all new technologies in low-charge systems, Barrett said. “The ability to alarm, monitor, and review system operation from one ‘supervisory’ HMI device has also been improved,” he said.

Additionally, control systems are getting smarter, package configurations are evolving to better match different building sizes or layouts, and there are more options to accessorize a design to fit specific needs and applications, Liebendorfer explained.

Fauser said contractors, manufacturers, and designers are challenging each other. The thermal space holds new opportunities for low-charge systems and natural refrigerants to play a bigger role in the fight against climate change. “When we look at heat and cold, there is no such thing as cold. There is heat or lack of heat. What we’re seeing as a trend is refrigeration systems are becoming thermal systems,” he explained. “As a thermal system, we’re looking at refrigeration, cooling, and heating.”

What makes the low-charge compatible with thermal designs is lowering the charge by putting a plate condenser on to recover the heat. “Because of this drive to net zero, this concept of one unit for thermal design makes sense from an environmental standpoint,” Fauser said.

As end-users continue to adopt low-charge systems, technology will continue to change. “With the rapidly growing installations, the foundation is being laid now for the next generation of these low-charge systems and CO2 transcritical systems. This includes packages that are able to handle larger cooling capacities, versatility in fitting application and building layouts, and smarter controls systems,” Liebendorfer said.