1

1

Refrigerants Refrigerants and theirand their

ApplicationApplication

Presented by

Thomas E. Watson, P.E.Fellow ASHRAE

McQuay InternationalStaunton, Virginia USA

11

What is a Refrigerant?What is a Refrigerant?

• In a refrigerating system, the medium of heat transfer

which picks up heat by evaporating at a low

temperature and pressure, and gives up heat on

condensing at a higher temperature & pressure.

• (Refrigerating fluid) fluid used for heat transfer in a

refrigerating system which absorbs heat at a low

temperature and low pressure of the fluid and

transfers heat at a higher temperature and higher

pressure of the fluid, usually involving changes of state

of the fluid.

Ref: ASHRAE Terminology of Heating, Ventilation, Air Conditioning, & Refrigeration

22

2

2

Agenda / TopicsAgenda / Topics

• Introduction

• History of Refrigerants

• Basic Refrigerant

Chemistry

• Refrigerant Properties

• Refrigerant Applications

• Refrigerants In The

Future?

• Alternative Refrigerants

• Ozone Depletion &

Montreal Protocol

• Global Warming

• Summary

33

History of RefrigerantsHistory of Refrigerants

• 1830s - Jacob Perkins - Vapor Compression (ether)

• 1851 - John Gorrie - Patent for Air Cycle

• 1859 - R-717 / R-718 (Ammonia / Water)

• 1866 - CO2 - Marine Applications

• 1873 - R-717 (Ammonia) Commercial Refrigeration -

Carl Linde

• 1875 - R-764 (Sulfur dioxide)

• 1920s -R-600a (Isobutane) & R-290 (Propane)

• 1922 - Willis Carrier - R-1130 (Dielene)

• 1926 - R-30 (Methylene Chloride)

44

3

3

Solving Problem of Toxicity was a Large Problem to Development of Refrigeration

1927 Leo Szilard &Albert Einstein

Improved on von Platen / Munters Absorption DesignElectromagnetic Pumping Patent

Toxicity Toxicity -- Best Minds Tried to SolveBest Minds Tried to Solve

55

Challenged to Find Refrigerant:Challenged to Find Refrigerant:

• Non-flammable

• Good Stability

• Low Toxicity

• Atmospheric Boiling Point between -40oC & 0oC

66

4

4

Common Refrigerants in 1920sCommon Refrigerants in 1920s

Ammonia (R-717) NH3

Carbon Dioxide CO2

Sulfur Dioxide SO2

Hydrocarbons CnHm

Methyl Choride CH3Cl

Water H2O

77

History of RefrigerantsHistory of Refrigerants

88

5

5

History of RefrigerantsHistory of Refrigerants

HC N O F

S ClBr

Midgley SelectionsMidgley Selections

99

Hydrocarbon Formula NBP

Methane CH4 -260 F -162 ̊C

Ethane C2H6 -127 F -88 ̊C

Propane C3H8 -44 F -42 C̊

Refrigerant ChemistryRefrigerant Chemistry

1010

6

6

Refrigerant ChemistryRefrigerant Chemistry

1111

Refrigerant ChemistryRefrigerant Chemistry

1212

7

7

Refrigerant ChemistryRefrigerant Chemistry

1313

Refrigerant ChemistryRefrigerant Chemistry

1414

8

8

FluorocarbonsFluorocarbons

• CFCs, HCFCs, HFCs & HFOs

• Limited Combinations

– Adding Chlorine Or Bromine

Increases ODP

– Adding Fluorine Increases

GWP

– Adding Hydrogen Increases

Flammability And Lowers

Atmospheric Lifetime

HYDROGEN

CHLORINE FLUORINE

Flammable

Toxic

Long Atmospheric Lifetime(fully halogenated)

Refrigerant ChemistryRefrigerant Chemistry

1515

Refrigerant ChemistryRefrigerant Chemistry

1616

9

9

Refrigerant ChemistryRefrigerant Chemistry

1717

Refrigerant ChemistryRefrigerant Chemistry

1818

10

10

• Refrigerant Blends

– Two or More Refrigerants to Achieve Required Properties

• Flammability

• Volumetric Capacity

• Limit Discharge Superheating for Lower Disch Temp

• etc

• Two Basic Types

– Zeotropes

– Azeotropes

Refrigerant ChemistryRefrigerant Chemistry

1919

ZeotropesZeotropes

100806040200

-5

5

15

25

35

45

55T vap

T liq

ZEOTROPIC BEHAVIOR (32/134a)

% R-32

Tem

per

atu

re, °F

P= 64 PSIA

100806040200

-5

5

15

25

35

45

55T vap

T liq

ZEOTROPIC BEHAVIOR (32/134a)

% R-32

Tem

per

atu

re, °F

P= 64 PSIA

Refrigerant ChemistryRefrigerant Chemistry

2020

11

11

Zeotropic BehaviorZeotropic Behavior

• Fractionalization - Can be Separated by Distillation

• Service Procedures

Refrigerant ChemistryRefrigerant Chemistry

2121

AzeotropesAzeotropes

100908070605040302010033

34

35

36

37

38

39

T vap

T liq

AZEOTROPIC BEHAVIOR (R-125/R-143a)

% R-125

Tem

per

atu

re,

°F

P=100 PSIA

R-507 = AZEOTROPIC MIXTURE R-125/R-143a (50/50)

Refrigerant ChemistryRefrigerant Chemistry

2222

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12

ASHRAE Standard 34ASHRAE Standard 34

2323

• Nomenclature

• Toxicity Classification

• Flammability Classification

ASHRAE Standard 34ASHRAE Standard 34

2424

13

13

ASHRAE Standard 34ASHRAE Standard 34

000 Series Methane Based

100 Series Ethane Based

200 Series Propane Based

300 Series Cyclic Organic Compounds

400 Series Zeotropes

500 Series Azeotropes

600 Series Organic Compounds

700 Series Inorganic Compounds

1000 Series Unsaturated Organic Compounds

Nomenclature

Code KeyCode Key

R - 1 2

+ 9 0

C H F

= 1 0 2

Rule of 90 - Example R-12

14

14

ASHRAE Standard 34ASHRAE Standard 34

2727

Entgegen Zusammen

HFOHFO--1234ye 1234ye StereoisomersStereoisomers

2828

15

15

• Toxicity Classification based on

Chronic (long term) Measure

- Class A has PEL > 400 PPM

- Class B has PEL < 400 PPM

PEL = Permissible Exposure Limit

ASHRAE Standard 34ASHRAE Standard 34

2929

• Flammability Classification based on:

ASTM E 681 with an Electrically

Activated match

ASHRAE Standard 34ASHRAE Standard 34

3030

16

16

Flammability Classification

• Class 1 - No Flame Propagation

• Class 2 - LFL > 0.10 kg/m^3

and hc < 19 MJ/kg

• Class 2L – Cl 2 w/ flame speed < 10 cm / sec

• Class 3 - LFL < 0.10 kg/m^3

or hc > 19 MJ/kg

ASHRAE Standard 34ASHRAE Standard 34

3131

ASHRAE Standard 34ASHRAE Standard 34

3232

17

17

A2L RefrigerantsA2L Refrigerants

3333

ASHRAE Standard 15ASHRAE Standard 15

3434

18

18

What is ASHRAE 15?

• An industry standard that specifies safe design, construction, installation, and operation of refrigerating systems

• Establishes safeguards for life, limb, health, and property, and prescribes safety standards

ASHRAE Standard 15ASHRAE Standard 15

3535

Scope

• Design, Construction, Installation, Operation & Inspection of Mechanical and Absorption Machines

• Modifications if not Identical in Function and Capacity

• Refrigerant Substitutions with Different Designation

ASHRAE Standard 15ASHRAE Standard 15

3636

19

19

RequirementsBased on 3 Classifications

• Occupancy

• Refrigerating System

• Refrigerant

ASHRAE Standard 15ASHRAE Standard 15

3737

Occupancy Classifications Occupancy Classifications -- Ability to Respond to ExposureAbility to Respond to Exposure

• Institutional - Assistance Required

• Public Assembly - Large Numbers

• Residential - Sleeping

• Commercial - Business Transactions

• Large Mercantile - 100 Persons or More

• Industrial & Refrigerated Rooms - Access Controlled

• Mixed - Two or More in Same Building

ASHRAE Standard 15ASHRAE Standard 15

3838

20

20

Refrigerating System Classification

• High Probability - Leak Can Enter Occupied Space

• Low Probability - Leak Cannot Enter Occupied Space

ASHRAE Standard 15ASHRAE Standard 15

3939

Restrictions on Refrigerant Use - Section 7

• Standard 15 Gives Rules based on Occupancy, System, & Refrigerant Classification

• 3 kg or Less of Flammable Refrigerants may be used in Listed Equipment

• A2L Refrigerant Application Requirements NOT Included – Presently Under Consideration

ASHRAE Standard 15ASHRAE Standard 15

4040

21

21

Refrigerant Qty/vol Limits - See Std 34

• Acute Exposure / Ability to Escape

• Direct Systems

• Volume - Space to which Refrigerant Disperses in Event of Leak

ASHRAE Standard 15ASHRAE Standard 15

4141

ASHRAE 15 Users ManualASHRAE 15 Users Manual

4242

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Location of inlet vents in relationto exhaust outlets ?

Location of roof drains ?

Rupture discoutlet locations ?

Purge vents to outside ?

Are safety rupturelines the right size ?

Is access to mechanicalroom restricted ?

Is there a tightseal on doors ?

Where do thefloor drains empty ?

Are drain valves connectedAre drain valves connectedto evacuation devices ?to evacuation devices ?

Are there anypit areas in theroom ?

Mechanical Room Safety CheckMechanical Room Safety Check

4343

Relief discharge shall be located not lessthan 20 ft (6 m) from ventilation opening andnot less than 15 ft (4.5 m) above ground level (9.7.8)

All indoor machineryrooms must be ventedto the outdoors utilizingmechanical ventilation98.13.3 & 4

Access to mechanicalroom shall be restricted.Tight fitting doors openingoutward (self closing if theopen into the building)adequate in number to ensure freedom of escape.No other openings that wouldpermit passage of escaping refrigerant (8.13)

Purge systems and relief devicesmust be vented to outside (8.16)

Refrigerant sensors are located in areas whererefrigerant vapor from a leak will be concentratedso as to provide warning at concentration notexceeding the refrigerant PEL

The total amount ofrefrigerant stored in amachinery room in all containers not provided with relief valves & piped in accordance with standard shall not exceed 330 lb (150 kg). (11.5)

Mechanical Room Safety CheckMechanical Room Safety Check

4444

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Entrance / Exits

Drains

PitsPits

Just Above floorJust Above floorNext to ChillersNext to Chillers

Refrigerant Storage

*Examples not part of standard

Sample Sensor Locations* Sample Sensor Locations*

4545

No open flames that usecombustion air from the machineryroom (boilers) can be locatedwithin the mechanical as long as the combustion air is ducted fromthe outside to the boiler or shutdown sensors are installed (8.13.6)

A change in the type of refrigerant in a system shall not be made without the notificationof the authority having jurisdiction, the userand due observance of safety requirements. Therefrigerant being considered shall be evaluated for suitability (5.3)

Mechanical room should bedimensioned for easyaccess to all parts and adequatespace for service, maintenance,and operation. Clear head roomof not less than 7.25 ft (2.2 m) below equipment situated overpassageways. (8.12.1 &2,8.13.1)

Periodic tests of detectors, alarms & ventilation must be performed in accordance with manufacturers recommendationsand/or local jurisdiction. (11.7.3)

Mechanical Room per ASHRAE 15Mechanical Room per ASHRAE 15

4646

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24

IIAR 2IIAR 2

4747

Back to the FutureBack to the Future

25

25

Refrigerants in the Future?Refrigerants in the Future?

Low Direct Global Warming Potential

• CO2

• Ammonia

• Hydrocarbons

• HFOs

4949

• Ammonia (NH3) R-717

– Efficient

– B2L Classification

– Industrial Applications

• Water R-718

– Absorption Chillers

– Centrifugal Compressors

– Axial Flow Compressors

• Carbon Dioxide (CO2) R-744

– Low Critical Point

Natural RefrigerantsNatural Refrigerants

5050

26

26

What about other stuff What about other stuff --HFOs?HFOs?

Refrigerant ApplicationsRefrigerant Applications

• pV = (m x Ru x T ) / MM

5252

27

27

Refrigerant ApplicationsRefrigerant Applications

• What is Pressure?

• Pressure = Average Impact of Molecules on a

given area.

• Pressure is dependent on the Kinetic Energy of

the molecules.

5353

Volumetric CapacityVolumetric Capacity

5454

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

0.1 1.0 10.0 100.0 1000.0

CFM/ton

Mo

lecu

lar

Mass

R-114

R-12

R-123

R-11R-245fa

R-1234zeR-1234yf

R-134aR-500

R-407CR-22

R-410AR-152a

R-32 R-40

R-290R-744

R-717 R-718

28

28

Compressor Types

Positive Displacement

Dynamic

Centrifugal

Axial

Reciprocating Rotary Orbiting

Scroll

Trochoidal

Singe Shaft

Single Screw

Moving Vane

Fixed Vane(Rolling Piston)

Twin Shaft Three Shaft

Twin Screw Tri-Screw

Compressor TypesCompressor Types

Compressor Volumetric Capacities

NOTE: Log Scale

0 1 10 100 1,000 10,000 100,000 1,000,000

Recip

Scroll

Rotary

Screw

Centrifugal

Axial

CFM

29

29

Refrigerant Flow RequirementsRefrigerant Flow Requirements

5757

0.1

1

10

100

1000

0.1 1.0 10.0 100.0 1000.0

CF

M/t

on

Suction Pressure, PSIA

R-114

R-12

R-123R-11

R-245fa

R-1234zeR-1234yf R-134a

R-500 R-407CR-22

R-410AR-32

R-40

R-290

R-744

R-717

R-718

• Compressors

– Vapor Pressure

– Temperature Lift

– Tons

• Evaporators

– Glide

• Condensers

– Glide

– Critical Temperature

Basic ConsiderationsBasic Considerations

5858

30

30

RR--11 Alternatives11 Alternatives

Refrigerant Molecular Mass

CFC-11 137.4

HCFC-123 153.0

HFC-245fa 134.0

5959

Refrigerant Molecular Mass

CFC-12 120.9

CFC-500 99.3

HFC-134a 102.0

HFO-1234yf 114.0

RR--12 Alternatives12 Alternatives

6060

31

31

RR--22 Alternative22 Alternative

Refrigerant Molecular Mass

HCFC-22 86.5

HFC-407C 86.2

6161

TEWI - Total Environmental Warming Impact

Consists of

• Direct GWP, from refrigerant discharge +

• Indirect, power plant CO2 discharge dominates

- Over 95% for Well Maintained Equipment

- CO2 from Power Generation depends on IPLV

Global WarmingGlobal Warming

6262

32

32

Global WarmingGlobal Warming

GWP

PowerGeneration

6363

�Ozone saving

�Global warming issue - Total Environmental Warming

Impact (TEWI)

�Safety

� Field availability

�Application

�Cost

�Compressor type

Summary Summary -- Refrigerant ChoiceRefrigerant Choice

6464

33

33

Questions?Questions?

6565

� www.ahri.org

� www.ashrae.org

� www.epa.gov/docs/ozone/index.html

� ASHRAE Handbook – Fundamentals - Refrigerants

� ASHRAE Standards 15 & 34

� IIR-2 Equipment, Design and Installation of Ammonia Mechanical Refrigerating

Systems

� Fluorocarbon Refrigerants Handbook - Ralph C. Downing, Prentice-Hall

� Trade-Offs in Refrigerant Selections: Past, Present, and Future - James M. Calm

and David A. Didion - Proceedings of ASHRAE/NIST Refrigerants Conference -

Oct 1997

� HFOS – New Low Global Warming Potential Refrigerants – S. F. Brown,

ASHRAE Journal August 2009

Information SourcesInformation Sources

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