New Generation Refrigeration

Lubricants Optimized for

Energy Efficiency

Sean O’MalleyDirector Sales and MarketingXaerus Performance Fluids Int’l

True Sustainable Refrigerants

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Carbon Dioxide (R-744) A1 GWP = 1 High pressure is a safety concern in some applications. Great for low temp, OK for certain medium temp and heat pump Efficiency drops off in high ambient conditions.

Ammonia (R-717) B2(B2L) (toxic) (applications limited to secondary expansion and chillers) GWP = 0

Hydrocarbons (R-600a, R-290, R-1270) GWP < 3 A3 (flammable) (charge restricted in most common applications)

True Sustainable Refrigerants

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Ultra Low GWP HFOs (R-1234yf, R-1234ze, R-1233zd, R-514A (blend)) GWP < 1-2 A2L (mildly flammable) or B1 (R-514A) Generally not well suited for high pressure applications on their own

Difluoromethane (R-32) GWP= 675 A2L, mildly flammable Best overall performance/cost alternative to R-410A for high pressure

Effects of Refrigeration Lubricants in System Energy Efficiency

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HFC, HCFC, HFO, Hydrocarbons, Carbon Dioxide

• System designed for oil to be Fully Miscible with refrigerant gas

• System efficiencies rely on:• Good oil return from evaporator• Oil retaining viscosity for adequate compressor bearing

lubrication• Oil maintaining properties as lubricant and sealing fluid for

screw compressors

Roles of Refrigeration Lubricants in System Energy Efficiency

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Ammonia

• System designed for oil to be Fully Immiscible with Ammonia gas

• System efficiency rely on:• Good oil separation• Oil remaining chemically stable with Ammonia• Oil return properties

Energy Efficient POE Refrigeration

Lubricants for:

- CO2 (R744)- HFO- R-32

R-744 (Carbon Dioxide)

Problems:• Smaller volume systems, higher pressure resulting in higher loads. • Solvency of carbon dioxide • Gas bubble nucleation (outgassing) on bearing surfaces destroys

lubricant film

Effects on energy efficiency:• Insufficient hydrodynamic lubrication• High mechanical wear and tear• High energy loss

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Limitations with Current POE Refrigerant Lubricants

R-32Problem:• Low miscibility of conventional POE with R-32 • Excessive oil dilution by R-32 relative to R-410A

Impact on system efficiency:• Decreased miscibility could impact oil return and reduce system efficiency• High dilution leads to poor lubrication of compressor high wear and tear and high

energy consumption

R-1234zeProblem:• High solubility and excessive oil dilution relative to R-134a

Impact• Lost of lubricant viscosity, poor compression, poor cooling efficiency

Limitations with Current POE Refrigerant Lubricants

Carbon Dioxide Refrigeration Lubricants

CO2 Compressor Lubricants Properties

PAO Type Oil return problem for transcritical system

First Generation POE Average miscibility and load carrying 

properties

Second Generation POE Superior load carrying for commercial/ 

industrial sub‐ and trans‐critical refrigeration 

and heat pump.

Development of Carbon Dioxide Refrigerant Lubricants

Load Carrying CapabilityFalex Pin and Vee Block TestASTM D 3233, Method A

Product Second Gen POE First Gen POE

Viscosity at 40 C 80 69

Falex Pin and Vee BlockTest Result

1000 900

Development of Carbon Dioxide Refrigerant Lubricants

Lubricant Miscibility in R‐744First Generation POE

-10

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5

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0 10 20 30 40

Tem

pera

ture

(ºC

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Concentration (wt% Lube in R-744)

Immiscible Region

Miscible Region

Lubricant Miscibility in R‐744Second Generation POE 

-10

-5

0

5

10

15

20

25

30

0 10 20 30 40

Tem

pera

ture

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Concentration (wt% Lube in R-744)

Immiscible Region

Miscible Region

HFO Refrigeration Lubricants

HFO Type Refrigeration Lubricants

R‐1234yf √ Conventional POE : OK

R‐1234zd √ Conventional POE : OK

R‐1234ze

X Conventional POE : Highly soluble in R‐1234ze  Loss of 

lubrication and compression, high energy wastage

√ New Generation POE for R‐1234ze: Designed to retain 

viscosity, miscibility and load carrying with R‐1234ze

HFO Refrigerant Lubricants

Traditional 220 ISO POE with R‐1234ze

Traditional POE Dilute Too Much with R‐1234zeNew Generation POE Solves this Problem

Refrigeration Lubricants Properties

Conventional POE X Poor miscibility with R‐32

New Generation POE for R‐32 √ Good miscibility with R‐32 

R‐32 Refrigerant Lubricants

Major R‐32 Miscibility Gap of Traditional POE 

R‐32 Refrigerant Lubricants

New Generation POE for R‐32: No Miscibility Gap

R‐32 Refrigerant Lubricants

Energy Efficient Refrigeration

Lubricants for:

- Hydrocarbons(e.g. Propane R290)

Refrigerant Gas Naphthenic Mineral Refrigeration Oil

HCFC (R‐22) √ Good miscibility and lubricating 

properties with R‐22

Propane (R‐290) X High dilution by propane gas, loss of 

lubricant viscosity High wear and tear 

due to insufficient lubrication, 

compressor failure

Retrofitting HCFC System to Hydrocarbon Refrigerant (e.g. propane)

Dilution Effect of Propane in Various Oil

Refrigerant Gas Refrigeration Oil

HCFC (R‐22)√ Mineral Naphthenic Mineral  

Refrigeration Oil

Propane (R‐290) √ Synthetic PAG Refrigeration Oil

Retrofitting HCFC System to Hydrocarbon Refrigerant (e.g. Propane)

Energy Efficient Refrigeration

Lubricants for:

- Ammonia(R717)

Energy Efficient Ammonia Refrigeration Lubricants

• Good Oil Return:• Low Pour Point of Lubricants

• Good Oil Separation and Low Oil Carry Over:• Oil with Low Ammonia Solubility• Good Thermal Stability

• System cleanliness:• Oil remains Chemically stable with Ammonia and non‐reactive (low sludge formation)

SOLUBILITY WITH AMMONIA (1550F / 460)C)

Optimized Paraffinic Group II

4.03.53.02.52.01.51.00.5

0PAO Paraffinic Naphthenic

Weight % Solubility in Ammonia

Ammonia Refrigeration Lubricant ‐ Solubility 

Paraffinic Naphthenic

2.0

1.5

1.0

0.5

0

EVAPORATION LOSS ASTM D972 – 22 Hours @ 100⁰C

Weight % Evaporation Loss

Optimized Paraffinic Group II

Ammonia Refrigeration Lubricant – Thermal Stability 

Ammonia Refrigeration Lubricant – Chemical Stability Oil Type Reactivity with Ammonia Energy 

Efficiency

Naphthenic Oil UNSTABLE‐ Reacts with Ammonia to form nitrogen compounds (Sludge)

Poor

AlkylBenzene Oil UNSTABLE‐ Reacts with Ammonia to form nitrogen compounds (Sludge)

Poor

Paraffinic Group II Oil with high impurity

UNSTABLE‐ Reacts with Ammonia to form sludge

Poor

Paraffinic Group II oil with high purity, pour point optimized

STABLE Good

Synthetic PolyAlphaOlefins STABLE Good

Ammonia Refrigeration Lubricant – Chemical StabilityCompatibility Results 120°C, 4 Weeks 

Alkyl Benzene Napthenic Mineral Oil

Group II High ImpuritiesGroup II High Purity

PolyAlphaOlefin

THANK YOU