Alternatives for HCFCs
in split type room
South America Workshop on low-GWP, energy-efficient HCFC
replacement technologies in the Refrigeration and Air Conditioning
Bogota, Colombia, 22-23 April 2010
DAIKIN Industries Ltd.
To phase-out HCFCs, alternatives to HCFCs should be chosen
carefully though overall evaluations:
1) Energy efficiency 2) Total emission 3)Safety 4) Economic aspects.
There are several candidates.
1. HFO1234yf : Low GWP and not efficient
2. HFC32 : Intermediate GWP and efficient
3. Propane(R290) : Natural and efficient but highly flammable
4. CO2(R744) : Natural but poor in efficiency
5. HFC410A : High GWP but applications are widely commercialized
This presentation shows the results of overall evaluations for
alternatives to HCFCs for split air-conditioning applications.
From the comprehensive points of view, we recommend R32 as the
best alternative to new split air-conditioners for the time being.
1. Properties of Alternative Refrigerants
2. Evaluation for alternatives
2) Total emissions
3) Safety measures
1. Properties of Alternative Refrigerants 4
Following table shows properties of alternative refrigerants to HCFC22.
Red areas show unsuitable properties as an alternative refrigerant.
Refrigerant physical properties
Cond. Capacity COP GWP Life
Press. ODP (IPCC4) Flamm- Toxicity
MPa R22 ratio R22 ratio Year ability
HCFC22 Single 1.73 100 100 0.05 1810 11.9 No Low
HFC407C Zoetrope 1.86 102 99 0 1770 - No Low
HFC410A Azeotorope 2.72 141 92 0 2090 - No Low
R32 Single 2.80 160 97 0 675 5 Low Low
HFO1234yf Single 1.16 57 90 0 4 7day Low ?
HFO mixture ? ? Under investigation
? ? ? ? ? ? Low
Propane (R290) Single 1.53 83 98 0 3 - High Low
CO2(R744 ) Single 10.00 243 41 0 1 120 No Low
Ammonia (R717) Single 1.78 116 106 0 0 0 Low High
In case of
Candidates for preventing Residential A/C
global warming Commercial A/C
Note: Ammonia is not considered as a candidate refrigerant for small air-conditioners due to its high toxicity
2.1 Energy-efficiencies 5
•Annual efficiency (APF) comparison •Peak power comparison
(R410A ratio) Case of 4kW Room A/C by JRAIA (R410 ratio) under cooling condition
Efficiency ratio Power ratio
As for annual efficiency of APF, CO2 is the A big difference exists in the peak power
worst, HFO needs further optimization, and under cooling condition. HFO and CO2 will
the rest of the candidates are equivalent to cause the peak power problem in large cities.
Calculation conditions: HFO1234yf A/C is modified to improve efficiency, such as an increase in the pipe size of heat
2.2 Total Emissions 6
LCCP comparison (4kW Room A/C)
Total emissions = Indirect emissions+Direct emissions+Emissions during producing refrigerant
JRAIA; in China 09.4.4 Indirect impact
R32 (1.2kg) refrigerant recovery rate is 30%
which is current rate in Japan.
LCCP (Life Cycle Climate
Performance) means the sum of
R744 (1.05Kg) "the warming impact during
refrigerant production” (which is
R410A (1.4kg) negligible compared to HCFC22) ,
(Refrigerant charge) “ the warming impact according to
energy consumption during
KgCO2 operation in life cycle” and
"the warming impact by emission
Consideration: of refrigerant“.
LCCP of R32 and propane are less in terms of total emissions.
The charge volume of R32 can be reduced by 40% compared to
HFO1234yf needs to be improved in efficiency to be practical.
2.3 Safety measures to use flammable refrigerants 7
(1) Current status of Safety standards to use flammable refrigerants
[International] ISO5149 and ISO817 are being drafted, IEC 60335-2-24, 40 and 89 are published
[European] EN378 is published
[U.S.] ASHRAEstd. 34 is published, and ASHRAEstd. 15 is now under a discussion.
[Japan] High Pressure Gas Safety Law
(2) Charge limits for DX-AC set by IEC Standard, without ventilation fan.
In the case of 10m2 room Flammable refrigerants are limited in charge
HFO1234< 3.02kg amount of DX-AC in IEC standard.
Maximum charge amount depends on
LFL and installation height.
In the case of wall mounted type, the charge
amounts stipulated in the std can be feasible
for small and medium sized ACs except
when using R290.
Room area(m2) When charge volume exceeds the limits,
leak detector and mechanical ventilation
2.3 Safety measures to use flammable refrigerants 8
(3) Consideration on the use of 2L refrigerants classified by ASHRAE34
Class 1 Class 2L Class2 Class3
(non-flammable) (Low flammable limit with low (Low flammable limit (High flammable and
burning velocity) with high burning velocity) higher heat of
CO2(R744 ) HFO 1234 R152a Propane (R290)
R22 Ammonia (Toxic)
1. Class 2L is similar to ammonia which caused no flammable accidents.
Consideration is on going to clarify the safety requirements to use 2L refrigerants
2. Refrigerators, Commercial refrigeration and MAC(wrong use) which employed R290
caused fire accidents in the fields.
<Fire accident examples>
Beer cooler incident in Australia Refrigerators Explosion Propane explosion in a New
10/19/95, CA: charging while engine in UK and South Korea Zealand supermarket.
was still hot
8/18/96, MS: low pressure hose from
evaporator blew off
9/27/96, AR: torch used on truck AC
unit after venting refrigerant
Source: US-EPA in Bogota 2008
Source Telegraph.co.uk Source: EFCTC newslettr
Fire accident in case of:fuel use: ave.68/yr, death: ave.1.3/yr (01-06) ,:Source METI Japan
2.4 Costs 9
(1) Factors of Cost Fluctuation Component which
Refrigerant price Cheap Cheap Expensive Cheap
Cost for performance
Compressor, Same as R22 Near as R410 Larger comp. Two-stage comp.
EX, etc. Same as R22 Same as R410 Larger pipe etc. High-pressure etc.
Cost for safety
Charge reduction Important (ex.230g) Necessary Necessary Necessary
Joint Special joint Special joint Special joint Unnecessary
Electronic parts Sealing etc. Sealing etc. Sealing etc. Unnecessary
Leak detector Necessary Unnecessary Unnecessary Unnecessary
Ventilation Necessary Unnecessary Unnecessary Unnecessary Required in
Cost for handling Japan
Manufacture Special facility Modified facility Modified facility Modified facility
Supply chain Qualification Modification Modification Qualification
Installation Qualified person Modification Modification Qualified person
Service Qualified person Modification Modification Qualified person
Disposal Qualification Modification Modification Modification
Propane requires additional cost CO2 requires significant cost
when taking safety measures in for performance improvement.
application and handling.
The warming impact of refrigerants
= Not Suitable
When R32 is used, the charge
volume is reduced by 25%.
1. To evaluate not only GWP but also the total emissions.
In case of R32, higher efficiency and less refrigerant charge will lead lesser
emissions. Additional leakage prevention measures will contribute to
emission reduction further.
2. Higher flammable refrigerants have bigger risks, while handling
and under poor quality control, in addition by wrong use.
When charge volume is small, we recommend to use class A2L refrigerants,
by taking measures in accordance with IEC60335-2-40.
When charge volume is large, we recommend to use class A1 refrigerants
for the moment.
3. Use of efficient refrigerants brings economical benefits.
Higher peak power will cause problem energy supply.
CO2 application requires significant cost for performance improvement, and it
can be used for limited applications.
4. HFC32 is the most practical solution for the time being.
HFO mixture could be a candidate; however, it needs further improvement to
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