Refrigerants and Their Application

Refrigerants and their Application

Presented by Thomas E. Watson, P.E. Fellow ASHRAE McQuay International Staunton, Virginia USA

• 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

1 1 Agenda / Topics

• Introduction • Refrigerants In The • History of Refrigerants Future? • Basic Refrigerant • Alternative Refrigerants Chemistry • Ozone Depletion & • Refrigerant Properties Montreal Protocol • Refrigerant Applications • Global Warming • Summary

History of Refrigerants

• 1830s - Jacob Perkins - Vapor Compression (ether) • 1851 - John Gorrie - Patent for Air Cycle • 1859 - R-717 / R-718 (Ammonia / Water)

• 1866 - CO 2 - 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)

2 2 Toxicity --BestBest Minds Tried to Solve

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

1927 Leo Szilard & Albert Einstein Improved on von Platen / Munters Absorption Design Electromagnetic Pumping Patent

Challenged to Find Refrigerant:

• Non-flammable

• Good Stability

• Low Toxicity

• Atmospheric Boiling Point between -40 oC & 0 oC

3 3 Common Refrigerants in 1920s

Ammonia (R-717) NH 3

Carbon Dioxide CO 2

Sulfur Dioxide SO 2

Hydrocarbons CnHm

Methyl Choride CH 3Cl

Water H2O

History of Refrigerants

4 4 History of Refrigerants

Midgley Selections H C N O F S Cl Br

Refrigerant Chemistry

Hydrocarbon Formula NBP

Methane CH4 -260 F -162 C̊

Ethane C2H6 -127 F -88 C̊

Propane C3H8 -44 F -42 C̊

1010

5 5 Refrigerant Chemistry

1111

Refrigerant Chemistry

1212

6 6 Refrigerant Chemistry

1313

Refrigerant Chemistry

1414

7 7 Refrigerant Chemistry

Fluorocarbons

• CFCs, HCFCs, HFCs & HFOs HYDROGEN • Limited Combinations Flammable – Adding Chlorine Or Bromine Increases ODP

– Adding Fluorine Increases Toxic GWP – Adding Hydrogen Increases Flammability And Lowers Atmospheric Lifetime CHLORINE FLUORINE Long Atmospheric Lifetime (fully halogenated)

1515

Refrigerant Chemistry

1616

8 8 Refrigerant Chemistry

1717

Refrigerant Chemistry

1818

9 9 Refrigerant Chemistry

• 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

1919

Refrigerant Chemistry

Zeotropes

ZEOTROPIC BEHAVIOR (32/134a)

55 T vap T liq 45

35 P= 64 PSIA 25

15 Temperature, °F Temperature,

-5 0 20 40 60 80 100 % R-32

2020

10 10 Refrigerant Chemistry

Zeotropic Behavior • Fractionalization - Can be Separated by Distillation • Service Procedures

2121

Refrigerant Chemistry

Azeotropes

AZEOTROPIC BEHAVIOR (R-125/R-143a) 39

T vap 38 T liq

, °F 37 P=100 PSIA 36

Temperature 35 R-507 = AZEOTROPIC MIXTURE R-125/R-143a (50/50)

33 0 10 20 30 40 50 60 70 80 90 100

%R-125

2222

11 11 ASHRAE Standard 34

2323

ASHRAE Standard 34

• Nomenclature • Toxicity Classification • Flammability Classification

2424

12 12 ASHRAE Standard 34

Nomenclature

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 Com pounds

Code Key

Rule of 90 - Example R-12

R - 1 2

+ 9 0 C H F

= 1 0 2

13 13 ASHRAE Standard 34

2727

HFOHFO--1234ye1234ye Stereoisomers

Entgegen Zusammen

2828

14 14 ASHRAE Standard 34 • Toxicity Classification based on Chronic (long term) Measure - Class A has PEL > 400 PPM - Class B has PEL < 400 PPM PEL = Permissible Exposure Limit

2929

ASHRAE Standard 34

• Flammability Classification based on:

ASTM E 681 with an Electrically Activated match

3030

15 15 ASHRAE Standard 34

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

3131

ASHRAE Standard 34

3232

16 16 A2L Refrigerants

3333

ASHRAE Standard 15

3434

17 17 ASHRAE Standard 15

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

3535

ASHRAE Standard 15 Scope • Design, Construction, Installation, Operation & Inspection of Mechanical and Absorption Machines • Modifications if not Identical in Function and Capacity • Refrigerant Substitutions with Different Designation

3636

18 18 ASHRAE Standard 15

Requirements Based on 3 Classifications • Occupancy • Refrigerating System • Refrigerant

3737

ASHRAE Standard 15 Occupancy Classifications --AbilityAbility 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

3838

19 19 ASHRAE Standard 15

Refrigerating System Classification

• High Probability - Leak Can Enter Occupied Space • Low Probability - Leak Cannot Enter Occupied Space

3939

ASHRAE Standard 15

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

4040

20 20 ASHRAE Standard 15

Refrigerant Qty/vol Limits - See Std 34 • Acute Exposure / Ability to Escape • Direct Systems • Volume - Space to which Refrigerant Disperses in Event of Leak

4141

ASHRAE 15 Users Manual

4242

21 21 Mechanical Room Safety Check

Location of inlet Location of roof drains ? vents in relation to exhaust outlets ?

Rupture disc outlet locations ? Is there a tight Purge vents seal on doors ? to outside ? Are safety rupture lines the right size ? Is access to mechanical room restricted ?

Are drain valves connected to evacuation devices ?

Are there any Where do the pit areas in the floor drains room ? empty ?

4343

Mechanical Room Safety Check

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

All indoor machinery rooms must be vented Purge systems and relief devices to the outdoors utilizing must be vented to outside (8.16) mechanical ventilation 98.13.3 & 4 Access to mechanical room shall be restricted. Tight fitting doors opening outward (self closing if the open into the building) adequate in number to ensure freedom of escape. No other openings that would permit passage of escaping refrigerant (8.13)

Refrigerant sensors are located in areas where The total amount of refrigerant vapor from a leak will be concentrated refrigerant stored in a so as to provide warning at concentration not machinery room in all containers not provided exceeding the refrigerant PEL with relief valves & piped in accordance with standard shall not exceed 330 lb (150 kg). (11.5)

4444

22 22 Sample Sensor Locations*

Entrance / Exits

Refrigerant Storage Just Above floor Next to Chillers Drains Pits

*Examples not part of standard

4545

Mechanical Room per ASHRAE 15

Periodic tests of detectors, alarms & ventilation must be Mechanical room should be performed in dimensioned for easy accordance with access to all parts and adequate No open flames that use manufacturers space for service, maintenance, combustion air from the machinery recommendations and operation. Clear head room room (boilers) can be located and/or local of not less than 7.25 ft (2.2 m) below within the mechanical as long as jurisdiction. (11.7.3) equipment situated over the combustion air is ducted from passageways. (8.12.1 &2,8.13.1) the outside to the boiler or shut down sensors are installed (8.13.6)

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

4646

23 23 IIAR 2

4747

Back to the Future

24 24 Refrigerants in the Future?

Low Direct Global Warming Potential

• CO2

• Ammonia

• Hydrocarbons

• HFOs

4949

Natural Refrigerants

• Ammonia (NH 3) R-717 – Efficient – B2L Classification – Industrial Applications • Water R-718 – Absorption Chillers – Centrifugal Compressors – Axial Flow Compressors

• Carbon Dioxide (CO 2) R-744 – Low Critical Point

5050

25 25 What about other stuff --HFOs?HFOs?

Refrigerant Applications

• pV = (m x Ru x T ) / M M

5252

26 26 Refrigerant 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 Capacity 180.0 R-114 160.0 R-123 140.0 R-245fa R-11 120.0 R-12 R-1234yf R-1234ze 100.0 R-500 R-134a

R-22 R-407C 80.0 R-410A Molecular Mass Molecular R-152a 60.0 R-32 R-40 R-744 40.0 R-290

20.0 R-717 R-718

0.0 0.1 1.0 10.0 100.0 1000.0 CFM/ton

5454

27 27 Compressor Types

Compressor Types

Positive Dynamic Displacement

Reciprocating Rotary Orbiting Centrifugal

Singe Shaft Twin Shaft Three Shaft Scroll Axial

Single Screw Twin Screw Tri-Screw Trochoidal

Moving Vane

Fixed Vane (Rolling Piston)

Compressor Volumetric Capacities

Axial

Centrifugal

Screw

Rotary

Scroll

Recip

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

NOTE: Log Scale CFM

28 28 Refrigerant Flow Requirements

1000 R-718

100

R-123 R-11 R-245fa 10 R-114 R-1234ze CFM/ton R-1234yf R-134a R-40 R-12 R-22 R-407C R-500 R-290 1 R-717 R-32 R-410A

R-744

0.1 0.1 1.0 10.0 100.0 1000.0 Suction Pressure, PSIA

5757

Basic Considerations

• Compressors – Vapor Pressure – Temperature Lift – Tons • Evaporators – Glide • Condensers – Glide – Critical Temperature

5858

29 29 RR--1111 Alternatives

Refrigerant Molecular Mass

CFC-11 137.4

HCFC-123 153.0

HFC -245fa 134.0

5959

RR--1212 Alternatives

Refrigerant Molecular Mass

CFC-12 120.9

CFC-500 99.3

HFC-134a 102.0

HFO-1234yf 114.0

6060

30 30 RR--2222 Alternative

Refrigerant Molecular Mass

HCFC-22 86.5

HFC-407C 86.2

6161

Global Warming

TEWI - Total Environmental Warming Impact Consists of • Direct GWP, from refrigerant discharge + • Indirect, power plant CO2 discharge dominates - Over 95% for Well Maintained Equipment

- CO 2 from Power Generation depends on IPLV

6262

31 31 Global Warming

GWP

Power Generation

6363

Summary --RefrigerantRefrigerant Choice

Ozone saving Global warming issue - Total Environmental Warming Impact (TEWI) Safety Field availability Application Cost Compressor type

6464

32 32 Questions?

6565

Information Sources

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

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33 33