The Risks of Low Quality
Refrigerants

Introduction
In the current landscape of continually evolving

including latent heat of vaporization, thermal

Chemours brings over 85 years of history andregulations to meet global environmental goals,

conductivity, density, viscosity, oil solubility,

proven leadership in refrigerant science andthere is no lack in diversity when it comes to thetoxicity, flammability, cost, safety, environmental

pioneered much of the technology that makes

portfolio of available refrigerants. Due to theimpact, and others. Poor refrigerant quality (alsoair conditioning and refrigeration possible

abundance of refrigerant options and associatedreferred to as purity) can have adverse effects

today. This rich history is a direct result ofconfusion with respect to their differences, coston these critical properties. Without the adher-

a commitment to product quality.

is often given a significant weight when deciding

ence to a recognized and well-defined quality

which refrigerant to select. Cost, however, is astandard, the end-user has no assurance that

small piece of the larger picture.

a refrigerant will perform as advertised. More-Refrigerant design and selection by application isbased on the optimum combination of properties,

over, there is no guarantee that one charge ofrefrigerant will perform the same as the next.

2Purity Standards

Deviations from Standard

The ASHRAE Refrigeration handbook states

Moisture in a Refrigeration Systemthat “the primary resource for refrigerant purity
specification and composition information is
the Air Conditioning, Heating, and Refrigeration
Institute’s (AHRI) Standard 700.”1 This standard

temperature. As an example, the moisturesolubility of R-134a over a range of temperatures

The maximum amount of moisture allowedis shown in Figure 1.

before issues present themselves is a functionof the refrigerant being used and the low side

establishes purity specifications, verifies
refrigerant composition, and specifies theFigure 1: R-134a Moisture Solubility vs. Temperatureassociated methods of testing for acceptabilityof listed refrigerants. Purity is quantified
1200

to contaminants, including moisture, noncondensables, volatile impurities, high boiling
residue, particulates and solids, acidity, andchloride.2
Chemours Freon™ and Opteon™ refrigerant lines
are manufactured, packaged, and tested to meet
AHRI Standard 700. While adherence to thisstandard is voluntary, it provides more than justpeace of mind to end-users. Significant impacts
to system operation, total cost of ownership,and user safety could occur due to poor
refrigerant purity.

Moisture Solubility (ppm by weight)

in AHRI Standard 700 by assigning limits

1000
800
600
400
2000-40-20020406080

100

Temperature (ºF)
Note: Data on R-134a was obtained from Althouse, Andrew D., et al. Modern Refrigeration and Air Conditioning

3Because the moisture solubility of a refrigerant

refrigerant and freeze. The result is restricted

decreases with decreasing temperature, equip-or clogged flow paths.3 Signs of a restricted

ment like expansion valves and capillary tubes

flow path caused by moisture freezing in an

are especially vulnerable. If temperatures areexpansion valve can be seen in Figure 2.

low enough, moisture will separate from theFigure 2: Signs of a Restricted Flow Path
Lower Condenser
Temperature

Lower Head
Pressure

TXV with
Restriction

Lower Suction
Pressure
Lower
Evaporator
Temperature

Higher Conditioned
Space Temperature

The Risks of Low Quality Refrigerants4

A restricted thermostatic expansion valve (TXV)

occupy reduces the surface area available

or orifice allows less refrigerant to pass into thefor the refrigerant to transfer heat, thereby

evaporator. While the resulting lower pressuresdecreasing system performance.

and temperatures may seem beneficial, less refrigerant passing through the evaporator means
less latent heat is absorbed. This will cause
the conditioned space or fluid temperature torise. Conversely, moisture frozen in a TXV canprevent the valve from closing during an Offcycle. This causes the evaporator to flood during
the Off cycle, which can lead to liquid carryoverto the compressor or short cycling when thesystem is On.

3In addition to restricted flow paths, moisturein the presence of refrigerants and oils has thepotential to create an acidic environment. The
effects of acidity are discussed later.
Non-Condensables
Inerts, non-absorbable gas (NAG), non-condensable gas (NCG), or simply non-condensables are
all terms used to reference gases such as air,nitrogen, argon, carbon dioxide, and oxygen.

The amount of heat exchanged (q) in a condenser
can be expressed using the following equation:q = U0A0Δt
Where U0 is the overall heat transfer coefficient,
A0 is the heat transfer surface area, and Δt is

the temperature difference that applies to thespecific heat exchanger.4

With a fixed condenser load (q) required to reject
heat (from both the evaporator and the workof compression) and a relatively constant heattransfer coefficient (U0), the equation above

can be used to visualize that a reduction in heattransfer area (A0) equates to an increase in

the condenser Δt. An increase in Δt means anincrease in the average condenser refrigerant
temperature and pressure. Higher than expectedcondensing pressures are typically the telltale
sign of non-condensables present in a system.

When present within a refrigeration system,
non-condensables migrate to and are trapped in
the condenser. The volume which these gases
5

Safety Classifications and Flammability Parameters
Opteon™ XP40 (R-449A) was used to depict(COP) and cooling capacity decrease while mass

increased evaporator temperatures (i.e., uncom-the relative trends resulting from increased

flow requirements increase. Decreases in COP

fortable building occupants in the case of an air

condenser temperature as seen in Figure 3.

and capacity would manifest in the form of higher

handling unit or warm dairy products in the caseelectric bills. Additionally, system compressorsof a supermarket reach-in cooler).

As the percentage of non-condensables

may not be able to maintain the increasing

increase, the average condenser temperature
increases. With increases in average condenser
temperature, note that coefficient of performancemass flow rate requirements associated withhigher condensing temperatures. The result isVolatile Impurities
This section of AHRI Standard 700 defines
the permissible amount of volatile impurities.

Figure 3: Opteon™ XP40 (R-449A) Relative Performance vs. Condensing Temperaturepresence of other refrigerants. Often referred to60

as contamination, these impurities could causea host of issues, including increased energy

40

Change (%)

Included in the definition of impurities is theusage, decreased cooling capacity, premature
equipment wear, and even equipment failure.

20

When the composition of a refrigerant is altered0with impurities, the ability to troubleshoot thesystem with the use of published refrigerant-20properties is lost entirely.

-40-60High Boiling Residue, Particulates, and Solids
1020304050Condenser Temperature Increase (%)
Amount of Non-Condensables

COPCooling Capacity (BTU/lb)

An abundance of high boiling residues, particulates,or solids can plug equipment like capillary tubes,

Mass Flow (lb/hr)

Performance trends were generated using Opteon™ XP40 (R-449A) with a 0°F evaporator set point and a 1 tonne cooling load.

orifices, and even mist eliminators. Expansion
valves can stick, causing too much or too little
refrigerant to enter the evaporator. Residue

6can also cover heat transfer surfaces, thereby

formation.1 Acid within a system can attack

reducing cooling capacity. Solids present incopper and steel causing thinning of piping or

the refrigerant can cause premature wear andeven pinhole leaks. Free copper within a system

eventual failure of compressor components.

resulting from acid attack has been known to5

plate on steel bearing surfaces, reducing
Acidity and Chlorides
Synthetic lubricants such as polyol esters(POEs) used in the majority of refrigeration
systems today absorb considerably moremoisture than previously used mineral oils.
These synthetic lubricants have the potential
to decompose in the presence of moisture toform acids. Heat (i.e., high temperatures fromthe compression process) accelerates the acidclearances and increasing wear. Free copper
can also be transported to the expansion
devices causing them to malfunction.6 Acid canalso attack some types of motor insulation inhermetic compressors, resulting in motor
failure. Finally, lubricants can mix with acidpresent within the refrigerant, creating a sludge
that reduces the ability to lubricate key systemcomponents.17

Final Remarks

Within a refrigeration system, poor refrigerant

the core of everything we do. To align with thesepurity will adversely affect energy

values, we manufacture, package, and test

performance, system capacity, equipment life,

all Chemours refrigerants to meet the AHRI

and the over-all safety of operators and users.

700 purity standard. The result is a safe andThe purity of refrigerants can only beeffective product that customers can trust forguaranteed through the strict adherence tohigh-performing, reliable operation.

purity standards.
At Chemours, customer centricity, unshakable
integrity, and an obsession with safety are

8
The Risks of Low Quality RefrigerantsReferences
1

2018 ASHRAE Handbook Refrigeration. American Society of Heating, Refrigerating, and Air Conditioning Engineers, 2018.

2

Air-Conditioning, Heating, and Refrigeration Institute. (2017). AHRI Standard 700 Standard 700: Specifications for Refrigerants.

3

Althouse, Andrew D., et al. Modern Refrigeration and Air Conditioning. The Goodheart-Willcox Company, Inc., 2014.

42018 ASHRAE Handbook HVAC Systems and Equipment Chapter 48. American Society of Heating, Refrigerating, and Air Conditioning Engineers, 2018.

5Sporlan Valve Company. (2004). BULLETIN 240-10-3. CONTAMINANT REMOVAL FROM CENTRIFUGAL SYSTEMS.

6

Sanvordenker, K.S. “Chemical Aspects of Refrigerant Systems.” (1972). International Compressor Engineering Conference. Paper 75. http://docs.lib.purdue.edu/icec/75

9About Opteon™ Refrigerants
The Opteon™ refrigerants portfolio offers the optimal balance of environmental sustainability,performance, safety, and cost to help meet both regulations and business goals.
Specifically, in Europe, the very low GWP Opteon™ XL refrigerant portfolio supports the market
transitions required by the F-Gas Regulation and enables customers to select their optimal
solution – considering performance, safety, sustainability, and total cost of ownership.
Businesses trust Opteon™ refrigerants because they offer: ow GWPL
Up to a 99% reduction compared to previous
refrigerant generations.

Energy Efficiency
Reduced energy use creates long-termsavings over the system’s life.

Zero ODPThe HFO-based refrigerant family is
non-ozone depleting.

Long-Term Regulatory Compliance
HFO-based refrigerants can meet or exceed
global and local regulatory standards.

Ease-of-Conversion
Minimizing conversion costs and downtime.

Knowledgeable Experts
With more than 85 years of industry
experience, Chemours refrigerant experts
can help customers achieve both complianceand peak performance.

Excellent Capacity
A near match to many HCFC- and HFC-basedtechnologies.

Visit Opteon.com/regulations for more information on HFC replacements or to contact our experts.

The information set forth herein is furnished free of charge and based on technical data that Chemours believes to be reliable. Chemours makes no warranties, express or implied, and assumes noliability in connection with any use of this information. Nothing herein is to be taken as a license to operate under or a recommendation to infringe on any patents or trademarks.
©2020 The Chemours Company FC, LLC. Opteon™ and any associated logos are trademarks or copyrights of The Chemours Company FC, LLC. Chemours™ and the Chemours Logo aretrademarks of The Chemours Company. C-11901 (4/21)