Conference PaperPDF Available

Refrigerant types, issues, trends and future options

Authors:
  • Mahle Engine Components India Pvt. Ltd.

Abstract and Figures

Seminar is focused on the fundamentals of Vapor Compression refrigeration system which is principally applicable for all Automotive, Domestic and Industrial AirConditioning and Refrigeration Applications. Briefly, introduction to be given to the heart of the system, which is Compressor and types and functions. The flood of the Air-conditioner, that is, the refrigerants, their properties, merits and demerits are summarized to map the various types and their classifications. Detailed comparison is made on first generation, second generation and third generation refrigerants, including the option of using HCs and CO 2. Main focus is given to the Montreal Protocol and Kyoto Protocols. Possibilities of changeover from CFC/HCFC based refrigerants to HFC or HFO based third and fourth generation refrigerants are also covered. At the end of the session, all attendees would able get the absolute clarity on the function, selection and their merits and demerits of various Refrigerants in terms of design of the system and their components, ODP, GWP & TEWI indexes. Duration : 60 Minutes (2 Consecutive Sessions)
Content may be subject to copyright.
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
Page 1 of 16
Refrigerant types, issues, trends and future options
Track Code : C2 (Effective use of Unitary HVAC Systems in today’s Buildings)
Selvaraji Muthu
DGM-NTD,
Subros Limited,
C-51, Phase-2, Noida, U.P.
selvaraji.muthu@subros.com
+91- 9910307727
Aseem Kumar Jaiswal
AVP –R&D, NTD,
Subros Limited,
C-51, Phase-2, Noida, U.P.
ajaiswal@subros.com
+91- 9810435765
Abstract:
Seminar is focused on the fundamentals of Vapor Compression refrigeration system which is
principally applicable for all Automotive, Domestic and Industrial Air-Conditioning and Refrigeration
Applications. Briefly, introduction to be given to the heart of the system, which is Compressor and
types and functions. The flood of the Air-conditioner, that is, the refrigerants, their properties, merits
and demerits are summarized to map the various types and their classifications. Detailed
comparison is made on first generation, second generation and third generation refrigerants,
including the option of using HCs and CO2. Main focus is given to the Montreal Protocol and Kyoto
Protocols. Possibilities of changeover from CFC/HCFC based refrigerants to HFC or HFO based
third and fourth generation refrigerants are also covered. At the end of the session, all attendees
would able get the absolute clarity on the function, selection and their merits and demerits of
various Refrigerants in terms of design of the system and their components, ODP, GWP & TEWI
indexes.
Duration : 60 Minutes (2 Consecutive Sessions)
Keywords: CFC, HCHC, HFC, HFO, HC-Hydro Carbons, Co2 Refrigerants, Vapor Compression
Refrigeration system, ODP -Ozone Deletion Potential, GWP-Global warming Potential, TEWI-Total
Equivalent Warming Index, Montreal Protocol, Kyoto Protocol
CFC ; Chloro Fluro Carbons
HCFC : Hydro Chloro Fluro Carbons
HFC : Hydro Fluro Carbons
HC : Hydro Carbons
HFO : Hydro Fluro Olefins
Table of Contents:
1. Abstract 1
2. Introduction 2
3. Refrigerant Properties 3
4. Types of Refrigerants 3
5. Generation of Refrigerants 5
6. What is ODP? 6
7. Montreal Protocol 7
8. What is GWP? 9
9. What is TEWI? 11
10. Kyoto Protocol 11
11. Fourth generation Refrigerants 12
12. Future options 13
13. Conclusion 15
14. References 16
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
Page 2 of 16
2. Introduction:
Simple Vapor Compression Refrigeration System:
A simple vapour compression refrigeration system consists of the following equipments in the
sequence as shown in Fig-1:
i) Compressor ii) Condenser iii) Expansion valve iv) Evaporator.
Fig-1 Vapour Compression refrigeration Circuit
The change of state and their processes are listed as below.
C1 to D : Compression (Polytrophic) Compressor
D to E : De-super heating (Isobaric)
E to A : Condensation (Isobaric, Isothermal) Condenser
A to A1 : Sub-cooling (Isobaric)
A1 to B : Expansion (throttling, Isenthalpic) TXV Valve
B to C : Evaporation (Isobaric, Isothermal)
Evaporator
C to C1 : Super heating (Isobaric)
Function of Compressor:
To suck the Low Pressure refrigerant in vapour form from Evaporator
To compress the refrigerant to higher pressure with super heated vapour
To pump this high pressure high temperature super heated vapour to Condenser
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
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Fig-2, Classification of compressor Technologies
3. Refrigerant Properties
Irrespective of the size and efficiency of the individual parts in the vapour compression circuit, the
good refrigerant is the one, ensuring the highest overall effectiveness of the system.
Required Properties of Ideal Refrigerant:
1) Low boiling point and Low freezing point.
2) Low specific heat and High latent heat.
3) High critical pressure and temperature
4) Low specific volume to reduce the size of the compressor.
5) High thermal conductivity to compact evaporator and condenser.
6) Non-flammable, non-explosive, non-toxic and non-corrosive.
7) High miscibility with lubricating oil
8) High COP in the working temperature range.
9) Compatible with legal requirement
10) Availability and cost
4. Types of Refrigerants
The different types of refrigerants can be grouped as given below (ASHRAE 2008).
Methane
Group Ethane
Group Propane
group Zeotrope
mixtures Azeotrope
mixtures organic
compounds
inorganic
compounds
Series with
isolated
carbon
10 Series 100
Series 200
Series 400 Series 500 Series 600 Series 700 +mw
Series > 1100
Series
as per Numbering
Logic
Numbering Convention does not work as per
Numbering
Logic
R11 R123 R404a
•600
Hydrocarbo
ns
R717-
ammonia
NH3
R1100s
R1200s
R12 R134a R407c R507c •610
Oxygen
compounds
R718-
water R1234ze
R22 R410a
•620 Sulfur
compounds
R744- CO2
R1234yf
etc.. etc.. etc.. etc.. etc.. •630
Nitrogen
compounds
R729 - Air R1270 etc…
Table-1 : Grouping of refrigerants
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
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The numbering logic is explained as below.
R()13 4 a
isomer
# of fluorine atoms per molecule
# of hydrogen atoms + 1 per molecule
# of carbon atoms -1 per molecule (left off when 0)
# of unsaturated carbon bonds (left off when 0)
Fig-3 Numbering Logic for refrigerants
There is a simple methodology followed to decode the above numbering, which is shown as below.
# of Fluorine atoms per molecule
# of Hydrogen atoms per molecule
# of Carbon atoms per molecule
R134+90 =( ) 2 2 4
R1234+90=(1)3 2 4
R134+90 =( ) 2 2 4
R1234+90=(1)3 2 4
# of unsaturated carbon bonds
(left off when 0)
# of Chlorine atoms per molecule
(calculated from balance carbon bonding
Fig-4 Decoding of Refrigerants
Since, each refrigerants are having superiority in terms of different properties, there are mixtures
developed to arrive a required level of multiple properties to make the overall system performance
(COP) better.
The following classification is made to show the non-mixtures and mixtures.
Fig-5 Types of Refrigerants
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
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Table-2 Mapping of Refrigerants on Toxicity & Flammability
5. Generation of Refrigerants
Either or all of the 4 listed requirements are demanding the invention of new generation refrigerants
one after another (Calm 2008).
Zero ozone depletion potential (ODP)
low global warming potential (GWP)
short atmospheric lifetime (tatm)
high efficiency.
1st Generation Refrigerants
First generation refrigerants, used for almost one hundred years (1830 ~ 1930 ), were a variety of
volatile compounds ( ethers,CO2,NH3, SO2,HCs,H2O etc. ), that worked.
Ammonia (NH3), methyl chloride (CH3Cl), and sulfur dioxide (SO2) are toxic gases. Several fatal
accidents occurred in the 1920s because of methyl chloride leakage from refrigerators, which
pushed the entire world to look for next generation refrigerants.
2nd Generation Refrigerants
CFCs (1930s) and later HCFCs (1940s) were invented by Thomas Midgley Jr. (aided by Charles
Franklin Kettering).
As per the patent no. 2104882 (1931) of Thomas Midgley Jr., these halogen derivatives of aliphatic
mono-fluorides may be represented by the formula
CnHmFpXr in which
C represents carbon and n is the number of carbon atoms in the molecule which is always equal to
one or more.
H represents hydrogen and m is the number of atoms thereof, which may equal zero and still fulfill
the requirements of invention.
F represents fluorine and p is the number of atoms thereof which is always equal to one or more.
X represents chlorine, bromine or iodine or combinations thereof and r is the total number of such
atoms. r may be zero when p is greater than one
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3rd Generation Refrigerants
The third generation of refrigerants includes chemical groups, such as hydro-fluoro-carbons (HFCs),
that do not damage the ozone layer as that was the perceived environmental danger at the time.
However, as the effects of refrigerant leakages on global warming and climate change has become
evident, next generation refrigerants are required.
4th Generation Refrigerants
It is interesting that chemicals used in the first generation are being reconsidered as possible fourth
generation refrigerants. The `synthetic refrigerants' such as HFCs are being replaced with HFOs
(R1234ze, R12234yf) or `natural refrigerants'.
The concerns for safety, endurance and efficiency that encouraged evolution away from these
`natural refrigerants' in the past are still relevant now. For modern refrigerants there are even more
essential characteristics to be considered. These include:
Propane (R-290) and CO2 (R-744) are being proposed as new generation refrigerants, CO2 is non-
flammable, non-ozone depleting, non-toxic and has a GWP of 1.
The four generations included slightly overlapping periods as given below, (Calm JM, 2010).
1st Gen
1830 -1930s
CO2
NH3
SO2
HCs
H2O
…..
2nd Gen
1931 -1990s
CFCs
HCFCs
HFCs
NH3
H2O
…..
3rd Gen
1990 -2010s
HFCs
HCs
CO2
NH3
H2O
…..
4th Gen
2012 onwards
HFOs
HCFOs
HCs
CO2
NH3
H2O …
Global
Warming
Ozone Layer
Protection
Safety and
Durability
Whatever
worked
5th Gen
2020s ?
CO2
NH3
H2O …
Efficiency &
Trade-offs
Fig-6 Generations of Refrigerants
6. What is ODP?
ODP is Ozone Depletion Potential of with reference to CFC R11 as 1.
Frank Sherwood Rowland, Professor of Chemistry at the University of California, Irvine and Mario
Molina, who had got PhD in Chemistry at the University of California had together discovered that
CFCs decompose in sunlight, to release chlorine atoms. Chlorine atoms convert ozone to oxygen,
and can then attack other ozone molecules. A single atom can destroy millions of ozone molecules
before it is neutralized.
Cl + O3 -> ClO + O2
ClO + O3 -> Cl + 2O2
Molina and Rowland’s findings were published in 1974 and shocked the entire world. Their findings
were later confirmed by scientists around the world, especially the British Antarctic Survey in 1986.
This led to the Montreal Protocol of 1987 that banned CFCs around the world. They received the
Nobel Prize for Chemistry in 1995.
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
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CFCs Refrigerants:
HCFCs Refrigerants
Table -3 ODP of refrigerants (Montreal Protocol)
7. Montreal Protocol
The Montreal Protocol on Substances that Deplete the Ozone Layer is an international
treaty designed to protect the ozone layer by phasing out the production of numerous
substances believed to be responsible for ozone depletion. The treaty was opened for
signature on September 16, 1987.
Article A 5 (1) : Special situation of developing countries
Any Party that is a developing country and whose annual calculated level of consumption of the controlled
substances in Annex A is less than 0.3 kilograms per capita on the date of the entry into force of the Protocol
for it.
Fig-7 Phase-out of CFCs
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
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Fig-8 Phase-out of HCFCs
Fig-10 Ozone Chlorine Concentration (NASA report)
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
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Fig-11 Effective Stratospheric Chlorine Projection
8. What is GWP?
Global warming potential (GWP) is a measure of how much a given mass of greenhouse gas is
estimated to contribute to global warming. It is a relative scale that compares a gas to that of the
same mass of CO2 (GWP of CO2 is by definition 1).
Species Chemical
formula Lifetime
(years)
Global
Warming
Potential
(100 Years)
CO2 CO2 variable 1
Methane CH4 12 21
Nitrous
oxide N2O 120 310
HFC-23 CHF3 264 11700
HFC-32 CH2F2 5.6 650
HFC-41 CH3F 3.7 150
HFC-125 C2HF5 32.6 2800
HFC-134 C2H2F4 10.6 1000
HFC-134a CH2FCF3 14.6 1300
Table-4 GWP of refrigerants
Velders et al., PNAS, 2007
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
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Ref: The U.S. Response to the Kyoto Protocol, Kevin Klein, Professor of Economics, Illinois College
March 2, 2007
Fig-12 CO2 Concentrations
Fig-13 Emissions of CO2
World avoided by the
Montreal Protocol
Reduction Montreal Protocol of
~11 GtCO2-eq/yr
5-6 times Kyoto target
(incl. offsets: HFCs, ozone depl.)
CO
2
emissions
Velders et al., PNAS, 2007
Effects on climate
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
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9. What is TEWI?
Total equivalent warming impact (TEWI) is a measure used to express contributions of GHG to global
warming.
It is defined as sum of the direct (chemical emissions) and indirect (energy use) emissions of greenhouse
gases (GHG).
The method of calculating TEWI is provided below (AIRAH guide – methods of calculating TEWI):
TEWI = GWP (direct; refrigerant leaks incl. EOL) + GWP (indirect; operation)
= (GWP x m x L annual x n) + (GWP x m x (1- α recovery)) + (E annual x β x n)
Where:
GWP = Global Warming Potential of refrigerant, relative to CO2 (GWP CO2 = 1)
L annual = Leakage rate p.a. (Units: kg)
n = System operating life (Units: years)
m = Refrigerant charge (Units: kg)
α recovery = Recovery/recycling factor from 0 to 1
E annual = Energy consumption per year (Units: kWh p.a.)
β = Indirect emission factor (Units: kg CO2 per kWh)
10. Kyoto Protocol
The Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change
(UNFCCC), Kyoto, Japan, on 11 December 1997 that set binding obligations on the industrialized
countries to reduce their emissions of greenhouse gases.
Regional Shares of World Carbon Emissions, 1997 & 2020
Ref: The U.S. Response to the Kyoto Protocol, Kevin Klein, Professor of Economics, Illinois College
March 2, 2007
Fig-14 Regional Shares of World Carbon Emissions, 1997 & 2020
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
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11. Fourth Generation Refrigerants
HFO Refrigerants
HFO (hydro-fluoro-olefin) refrigerants are the fourth generation of fluorine-based refrigerants. HFC
refrigerants are composed of hydrogen, fluorine and carbon atoms connected by single bonds
between the atoms. HFO refrigerants are composed of hydrogen, fluorine and carbon atoms, but
contain at least one double bond between the carbon atoms.
The HFOs, currently being developed by DuPont and Honeywell, are HFO 1234ze and HFO
1234yf, which are having GWP of 6 & 3 respectively, replacement for R134a.
HFO-R1234yf HFO-R1234ze
CH2=CF-CF3 CHF=CH-CF3
Environmental
ODP = 0
GWP100 = 4
Atmospheric Life: 11 days
Environmental
ODP = 0
GWP100 = 6
Atmospheric Life: 18 days
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
-20 0 20 4 0 60 80 100
1234ze(E)
134a
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
-20 0 20 40 60 80 100
134a
1234yf
Vapor Pressure Vs. Temperature Vapor Pressure Vs. Temperature
Temperature, oC
Pressure, MPa
Pressure, MPa
Temperature, oC
Fig-15 HFO refrigerants Properties
Natural Refrigerants
Table-6 Natural refrigerants properties
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
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12. Future options
The transitions between successive generations required very large research, development, plant
construction, evaluation, product redesign, testing, training, and additional investments, but they
also created significant business opportunities.
While actual transition to the fourth generation has just begun, a number of challenges are
emerging that may dictate later transition to a fifth generation predicated in the absence of ideal
refrigerants.
Among the potential driving factors are efficiency, momentum, prices, litigation and liability,
unforeseen suitability issues, local impacts, and political aspects.
HFOs (R1234ze & R1234yf) & Natural refrigerants (NH3, CO2 etc..)
Fig-16 Comparison of R134a and R12234yf
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
Page 14 of 16
Ref: NIST Chemistry WebBook
Fig-17 PH Diagram of CO2
Important (ex.230g)
Special joint
Sealing etc.
Necessary
Necessary
Necessary
-
-
-
-
Necessary
Special joint
-
-
-
Necessary
Special joint
-
-
-
Cost for safety
Charge reduction
Joint
Electronic parts
Leak detector
Ventilation
Modified facility
Qualification
Qualified person
Qualified person
Two-stage comp.
High-pressure etc.
Cheap
CO2(R744)
Larger comp.
Larger pipe etc.
Near as R410A
Same as R410A
Modification required
Same as R22
Cost for performance
Compressor,
EX, etc.
Modified facility
Modification
Modification
Modification
Modification
Expensive
HFO1234yf
Cheap Cheap Refrigerant price
Modified facility
Modification
Modification
Modification
Modification
Special facility
Qualification
Qualified person
Qualified person
Qualification
Cost for handling
Manufacture
Supply chain
Installation
Service
Disposal
R32 Propane (R290)
Important (ex.230g)
Special joint
Sealing etc.
Necessary
Necessary
Necessary
-
-
-
-
Necessary
Special joint
-
-
-
Necessary
Special joint
-
-
-
Cost for safety
Charge reduction
Joint
Electronic parts
Leak detector
Ventilation
Modified facility
Qualification
Qualified person
Qualified person
Two-stage comp.
High-pressure etc.
Cheap
CO2(R744)
Larger comp.
Larger pipe etc.
Near as R410A
Same as R410A
Modification required
Same as R22
Cost for performance
Compressor,
EX, etc.
Modified facility
Modification
Modification
Modification
Modification
Expensive
HFO1234yf
Cheap Cheap Refrigerant price
Modified facility
Modification
Modification
Modification
Modification
Special facility
Qualification
Qualified person
Qualified person
Qualification
Cost for handling
Manufacture
Supply chain
Installation
Service
Disposal
R32 Propane (R290)
The Example of Room A/C Component which
increases cost
Fig-18 : mapping of various refrigerants and their challenge points
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
Page 15 of 16
13. Conclusion
Thomas Midgley (1928) had invented the CFCs & HCFCs, but the large use of these refrigerants
had created severe threat to the earth in terms of ozone layer depletion and global warming.
McNeill has stated that Midgley "had more impact on the atmosphere than any other single
organism in Earth's history.
Not only the inventors but all end users are more responsible for the consequences of usage of
refrigerants.
14. References:
1. ASHRAE, 2007, https://osr.ashrae.org/Public%20Review%20Draft%20Standards%20Lib/34z-
2007%201st%20PPR%20Draft.pdf
2. ASHRAE, 2008,
http://www.ashrae.org/File%20Library/docLib/Public/20080807_34m_thru_34v_final.pdf
3. Anant et al. Investigation of Cubic EOS models for HFO-1234yf Refrigerant Used in Automotive
Application, International Refrigeration and Air Conditioning Conference at Purdue, July 16-19,
2012
4. Björn Palm, REFRIGERANTS OF THE FUTURE, 10thIEA Heat Pump Conference 2011, 16 -
19 May 2011, Tokyo, Japan http://kth.diva-portal.org/smash/get/diva2:483181/FULLTEXT01
5. Calm JM, Composition Designations for Refrigerants, ASHRAE Journal, November 1989
6. Calm JM, Global Warming Impacts of Chillers, Heating Piping Air Conditioning, February 1993
7. Calm JM, Refrigerant Safety, ASHRAE Journal, 1994
8. Calm JM, The next generation of refrigerants - Historical review, considerations, and outlook,
Int. J. Refrig. 31 (7), 1123-1133 (2008). http://dx.doi.org/10.1016/j.ijrefrig.2008.01.013
9. Calm JM, Refrigerant Transitions ... Again. ASHRAE-NIST Refrigerants Conference 2012
10. Carmen J. Giunta THOMAS MIDGLEY, JR., AND THE INVENTION OF
CHLOROFLUOROCARBON REFRIGERANTS: IT AIN’T NECESSARILY SO , Bull. Hist.
Chem., VOLUME 31, Number 2 (2006)
11. CHARLES F. KETTERING , BIOGRAPHICAL MEMOIR of THOMAS MIDGLEY, JR. 1889-
1944, PRHSENTED TO THE ACADEMY AT THE ANNUAL MEETING, 1947.
12. Dylan S. Cousins and Arno Laesecke, Sealed Gravitational Capillary Viscometry of Dimethyl
Ether and Two Next-Generation Alternative Refrigerants Journal of Research of the National
Institute of Standards and Technology, Volume 117 http://dx.doi.org/10.6028/jres.117.014 ,
2012
13. G Venkatarathnam and S Srinivasa Murthy, Refrigerants for Vapour Compression Refrigeration
Systems, RESONANCE February 2012
14. GUIDE 2012: Natural Refrigerants Market Growth for Europe, shecco publications
15. Imke et al. Energy consumption of battery cooling in electric hybrid vehicles, International
Refrigeration and Air Conditioning Conference at Purdue, July 16-19, 2012
16. NASA, 2007, http://www.nasa.gov/vision/earth/environment/ozone_recovering.html Date:
March11, 2011
17. NIST Standard Reference Database 23, REFPROP - Thermo dynamic properties of refrigerants
and refrigerant mixtures, Version 3.04, NIST, USA, 1991.
18. M. Richter, M. O. McLinden, and E. W. Lemmon, Thermodynamic Properties of 2,3,3,3-
Tetrafluoroprop-1-ene (R1234yf): Vapor Pressure and p—ρ—T Measurements and an Equation
of State, J. Chem. Eng. Data 56 (7), 3254-3264 (2011). http://dx.doi.org/10.1021/je200369m
Paper submitted for ACRECONFINDIA 8th – 9th Feb’2013
Page 16 of 16
19. M. O. McLinden, M. Thol, and E. W. Lemmon, "Thermodynamic Properties of trans-1,3,3,3-
tetrafluoropropene [R1234ze(E)]: Measurements of Density and Vapor Pressure and a
Comprehensive Equation of State", Proceedings of the 2010 International Refrigeration and Air
Conditioning Conference, Purdue, West Lafayette, IN, USA, Paper No. 2189.
http://docs.lib.purdue.edu/iracc/1041/
20. Handbook for the Montreal Protocol on Substances that Deplete the Ozone Layer, Ninth edition
(2012), United Nations Environment Programme.
21. The Montreal Protocol and the Green Economy, 2012, UNEP.
THE AUSTRALIAN INSTITUTE OF
22. METHODS OF CALCULATING TOTAL EQUIVALENT WARMING IMPACT (TEWI),
AIRAH, Best Practise Guidelines, 2012,
23. KYOTO PROTOCOL TO THE UNITED NATIONS FRAMEWORK CONVENTION ON CLIMATE
CHANGE, 1998, UN.
24. Reasor, Pamela; Aute, Vikrant; and Radermacher, Reinhard, "Refrigerant R1234yf
Performance Comparison Investigation" (2010). International Refrigeration and Air Conditioning
Conference. Paper 1085 http://docs.lib.purdue.edu/iracc/1085/
25. R1234yf.fld - NIST, www.boulder.nist.gov/div838/theory/refprop/R1234YF.FLD
26. R1234ze.fld - NIST , www.boulder.nist.gov/div838/theory/refprop/R1234ZE.FLD
27. SAE, 2010a, http://www.sae.org/mags/aei/8702 , Date: April 22, 2011.
28. SAE, 2010b, http://www.sae.org/mags/AEI/8074 , Date: April 22, 2011.
29. SAE, 2011, http://www.sae.org/standardsdev/tsb/cooperative/altrefrig.htm , Date: April 22,
2011
30. http://www.reefercargocare.com/refrigerants.html
31. http://www.reefercargocare.com/ozone-depleting-substances.html
32. http://www.linde-
gas.com/en/products_and_supply/refrigerants/fluorine_refrigerants/hfo_refrigerants.html
33. http://humantouchofchemistry.com/frank-rowland-and-mario-molina.htm
34. http://www.beyonddiscovery.org/content/view.page.asp?I=89
35. Patents referred.
Inventor : Thomas Midgley
No. US
Patent
No. dated patent Title filed as on
1 2013062 Sep.3, 1935 Preparation of aliphatic halofluoro
compounds Feb. 26, 1931
2 2007208 July 9,1935 Manufacture of halo-fluoro
derivative of aliphatic
hydrocarbons Feb. 24, 1931
3 2104882 Jan.11, 1938 Heat transfer and refrigeration Nov.19, 1931
4 2024008 Dec.10, 1935 Manufacture of antimony
trifluoride June 30, 1934
5 2192143 Feb.27, 1940 Fluorination process May 7, 1938
Conference Paper
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Due to European and US norms and global efforts to reduce greenhouse gas emissions, Subros and other companies are examining the changeover from high GWP HFC refrigerants in the MAC sector, such as R134a, to alternatives. Alternatives include HFO-1234yf, HFO-1234ze, and CO2. All of these alternatives have their merits and demerits. The retrofitting of HFC-134a system by drop-in of HFO-R1234yf is expected to give the lesser cooling capacity by 8% with the lower Co-efficient of Performance (COP) by 6%. This effect of reduced cooling capacity was observed in the passenger compartment cool down temperature conducted at the vehicle level test conducted in the wind-tunnel at 40, 60 & 80 kmph and idle conditions. In order to match the performance (cooling capacity and COP) of current system using HFC-134a with the replacement of HFO-1234yf, an additional internal heat exchanger (IHX) has be used in the system in spite of the additional cost and space requirements for the implementation of this newer part. R-1234yf may require about a 5% increase in refrigerant vs. HFC-134a. The current HFC-134a PAG oil will not work with HFO- 1234yf; a new type of oil is required. HFO-1234yf can be recycled in the same way that HFC-134a has been in the past, but the service equipment needs to be manufactured to a different standard. Garages will require new RRR service equipment and will need to use it alongside their HFC-134a equipment. Leak detection equipment that meets the current standard will work with HFO-1234yf. Service ports are similar to HFC- 134a, however, they are smaller in size to prevent misuse. Testing found that the same desiccant type and quantity works with HFC-134a and HFO-1234yf. Participants discussed that CO2 must be in a trans-critical system; it cannot be used as a drop in. Secondary loop is an option for CO2. CO2 systems are complex and expensive and there are leakage problems. Honeywell has a contested application patent on HFO-1234yf.
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The viscosities of dimethyl ether (DME, C2H6O) and of the fluorinated propene isomers 2,3,3,3-tetrafluoroprop-1-ene (R1234yf, C3H2F4) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) were measured in a combined temperature range from 242 K to 350 K at saturated liquid conditions. The instrument was a sealed gravitational capillary viscometer developed at NIST for volatile liquids. Calibration and adjustment of the instrument constant were conducted with n-pentane. The repeatability of the measurements was found to be approximately 1.5 %, leading to a temperature-dependent estimated combined standard uncertainty of the experimental data between 5.7 % at 242 K for dimethyl ether and 2.6 % at 340 K for R1234yf. The measurements were supplemented by ab initio calculations of the molecular size, shape, and charge distributions of the measured compounds. The viscosity results for dimethyl ether were compared with literature data. One other data set measured with a sealed capillary viscometer and exceeding the present results by up to 7 % could be reconciled by applying the vapor buoyancy correction. Then, all data agreed within the estimated uncertainty of the present results. Viscosities for the fluorinated propene isomers deviate up to 4 % from values predicted with the NIST extended corresponding-states model. The viscosities of the two isomers do not scale with their dipole moments. While the measured viscosity of R1234ze(E) with the lower dipole moment is close to that of R134a, the refrigerant to be replaced, that of R1234yf with the higher dipole moment is up to 25 % lower. The viscosity of dimethyl ether is compared with those of water and methanol.
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REFPROP -Thermo dynamic properties of refrigerants and refrigerant mixtures, Version 3.04, NIST, USA
17. NIST Standard Reference Database 23, REFPROP -Thermo dynamic properties of refrigerants and refrigerant mixtures, Version 3.04, NIST, USA, 1991.