New refrigerants continue to dominate the conversation in the world of compressors as the sector deals with the regulation-induced demise of hydrofluorocarbons (HFCs) and prepares for the growth of hydrofluoroolefins (HFOs), hydrocarbons (HCs), and natural refrigerants, such as carbon dioxide (CO2).
Several leading compressor manufacturers weighed in with insights and advice for contractors and technicians as they learn how to work safely with the equipment utilizing these so-called alternative refrigerants as they transition into primary refrigerant choices.
For example, Johari Gregorio, senior technical support specialist, Embraco, advised technicians working with compressors that use HC refrigerants to carry out a risk assessment when working in an explosive environment, avoid open flames and other sources of ignition, and use only original components. The electrical components for Embraco compressors are compliant with the relevant international standards requiring encapsulated spark-proof enclosures, he noted.
In addition, technicians should always use an HC gas detector to sweep the work site before beginning any work and leave the detector in the lowest point in the area while working to monitor the site for HC gas buildup.
“HC refrigerants do not have an odorant because it is considered a system contaminant, so leaks can’t be identified by smell,” Gregorio said. “That’s why the use of an HC detector is mandatory.”
He added technicians must avoid removing an HC compressor with a torch and should instead use a tubing cutter. When installing a new compressor or part of the circuit, Gregorio advised using flameless equipment, such as lock-ring connections, instead of brazing.
Gregorio concluded that contractors and technicians looking to the future should source the correct equipment specific to HCs and follow up on the national and local applicable regulations.
“The general scenario about HCs is pretty dynamic, and it is important that [contractors and technicians] are up to date on the latest information from relevant organizations, like the U.S. Environmental Protection Agency [EPA], the Refrigeration Service Engineers Society [RSES], and, of course, resources like The NEWS,” he said.
EXPECT A WIDE RANGE OF REFRIGERANTS
Joel Moseley, general manager, Carlyle Compressor, said the company has seen trends in parts of the world and certain areas of the business where a shift to low-GWP (global warming potential) refrigerants is driven in part by government regulations.
“Because there is no one perfect refrigerant for all applications, this often prompts the use of a wide range of lower-GWP refrigerants and refrigerant blends,” Moseley said. “Some refrigerants will be limited in use because of flammability and toxicity concerns while others may be optimized for low temperatures but are not as energy efficient at medium-temp conditions.”
According to Moseley, Carlyle is committed to meeting the needs of its customers and maintaining a leadership position in environmental stewardship as it works with customers and industry affiliates to identify and standardize the best refrigerant solutions.
Moseley said Carlyle has requalified its legacy product for what he called interim refrigerants, such as R-448A and R-449A. In addition, the company is releasing new compressor lines that can handle multiple refrigerants, such as R-134a and R-1234ze, as well as a product that can support the natural refrigerant carbon dioxide.
“Our goal is to release products that can be used with multiple refrigerants,” he said. “This will allow equipment manufacturers and service technicians the flexibility to apply compressors in various refrigerant applications.”
A CALL FOR CAUTION
“Most technicians realize that a principal danger of CO2 is its potentially high pressures,” said Joe Sanchez, engineering manager, Bitzer US Inc. “For example, at a room temperature of 72°F, the pressure is 860 psig. So, when performing service on a CO2 system, a technician should treat the closing of any two valves that trap CO2 vapor, just like trapping liquid of a lower-pressure refrigerant and should be aware that a rapid pressure increase can occur.”
For this reason, Sanchez said, a technician should verify the maximum allowable pressures of the compressor before servicing it, keeping in mind there can be a maximum low-pressure rating and a separate maximum high-pressure rating.
“In addition, technicians should understand that CO2 compressors often have their own dedicated relief valves,” he said. “These are not intended for system use but exist to protect the compressor — and technician — when in service.”
Sanchez noted that when it comes to HFO and HC refrigerants, much attention is focused on the flammability of these products.
“However, one unrelated item to think about is that these refrigerants usually are much more soluble in oil than other refrigerants,” he said. “This means there should be increased caution in regards to superheat so that dry gas is returned to the compressor. Otherwise, the risk of refrigerant degassing, oil foaming, increased oil carryover, wear on the running gear, and a reduction of performance can occur. This is the main reason why you might see a higher recommended suction superheat for any compressor employing a refrigerant that uses HFOs, HCs, or a component of either.”
If you’re adaptable, change equals job security. And one thing our government has become very good at is creating change. That’s the word from Jim Rutz, global product director, Tecumseh Products Co. LLC.
“Whether or not you agree with the long-term premise, the major world governments have decided we need to save the environment, and they will help us by mandating efficiency improvements and the refrigerants we can use to do the work,” Rutz said. “It is our job to find a way to make those conflicting goals work together and do so while making our customers happy.”
Compressor manufacturers must try to satisfy the largest number of customers by creating value in the most cost-effective ways possible, Rutz said. The solutions the manufacturers arrive at find their way into new refrigeration equipment, which means service technicians need to be prepared to encounter this new technology in the field.
Rutz offered four tips to contractors and technicians who will soon be working with the next generation of compressors and refrigerants:
Tip No. 1: Learn the New Jargon — For the U.S. to do its part in reducing global warming, the EPA mandates the use of lower-GWP refrigerants. This is forcing a massive transition from hydrochlorofluorocarbon (HCFC-) and HFC-class refrigerants to HFO- and HC-class refrigerants. These new refrigerants come with A2L, A2, and A3 ASHRAE safety designations.
At this point, Rutz noted, technicians might well be saying “What?” to this alphabet soup.
“The mandates and rules that apply or are yet to be written will refer to this jargon, and if you are going to be in compliance, you will need to be able to understand the terminology,” Rutz said. “Otherwise, you and your customers will be exposed to considerable risk. Considerable risk, in plain English, means having a performance or safety issue.”
Tip No. 2: Using OEM Replacement Parts is a Must — Rutz provided an example of the ‘considerable risk’ mention in Tip No. 1. HC refrigerants, primarily R-290 (propane), are gaining widespread acceptance around the world in many refrigeration applications.
“As an A3 refrigerant in the U.S., current charge limits for R-290 circuits are 150 grams, or approximately 5.5 ounces,” Rutz said. “Can you charge a system with accuracy to individual grams? In addition, the start capacitors on these systems utilize bleed resistors to prevent sparking, and the overloads are sealed for the same reason. That’s why using OEM replacement parts is a must. Using a generic or universal replacement can get you into a safety or legal issue.”
Tip No. 3: Up Your Game and Focus on the Basics — Don’t overlook simple tasks like cleaning coils and avoiding unnecessary voltage drop.
According to Rutz, the new refrigerants of the future may be less efficient, lower in capacity, or a combination of the two when compared to their predecessors. However, government regulations demand higher efficiency, so compressor manufacturers engineer new designs to compensate for the losses.
“In single-speed compressors, these designs are engineered with less ‘excess’ capability, so it is more likely that occurrences, such as low-voltage or excessive head pressures, can lead to compressor start or run issues,” he said.
Tip No. 4: Never Stop Learning — Don’t be shy about asking your local wholesaler to sponsor a manufacturer’s school on these important topics. Rutz offers a final thought as contractors and technicians look to the future of compressors.
“The growth in electronic controls is going to be exponential,” he said. “Primarily because of the continued demand for high-efficiency, single-speed compressors will eventually become obsolete. The phaseout will not occur tomorrow or even the next few years, but it’s not that far down the road. Electronic controls and variable-speed compressors represent the next big jump in efficiency while maintaining system performance. Therefore, another new set of jargon and technical knowledge will need to be mastered.
“All of this change and the knowledge necessary to cope can seem overwhelming,” Rutz said. “You do not need to learn it all overnight. Compressor manufacturers are eager to help get you over the learning curve.”