PowerPoint *********

Report
Collaboration of JSRAE and SAME Okinawa Chapter
Risk Assessment of Mildly Flammable Refrigerants
2012 Progress Report
The Japan Society of Refrigerating and Air-Conditioning (JSRAE)
November 22, 2013
Akio MIYARA
Saga University
Department of Mechanical Engineering
Contents of the report
1 Introduction
2 Legal issues with mildly flammable refrigerant
2-1 Explanation of high pressure gas safety law and legal issues with mildly flammable refrigerant
2-2 Current international trends regarding refrigerant
3 Research on safety of mildly flammable refrigerants
3-1 Progress of the University of Tokyo
3-2 Research and development of low-GWP refrigerants suited to heat pump systems
3-3 Physical hazard evaluation of A2L-class refrigerants using several types of conceivable accident
scenarios
3-4 Progress report by research Institute for Innovation in Sustainable Chemistry, AIST
3-5 Physical hazard evaluation on explosion and combustion of A2L class refrigerants
4 Progress of the Japan Refrigeration and Air Conditioning Industry Association (JRAIA)
4-1 Mini-split air-conditioner risk assessment SWG: The risk assessment result of the residential
air-conditioner, and the study of the mini-split air-conditioner for small business use
4-2 VRF risk assessment SWG: The 1st risk assessment of VRF system with A2L refrigerant and future
4-3 Chiller risk assessment SWG: Risk assessments policy of the chiller and guideline planning taking
IEC60079 into consideration
5 Deregulation activities in Japan for the introduction of mobile air conditioning refrigerant R1234yf
File can be downloaded from “ http://www.jsrae.or.jp/info/2012progress_report_e.pdf ”
Background
Necessary & Indispensable Technology
Comfortable life
Refrigerating
Survive
Cold storage
Refrigerator car
Vapor compression
system
Refrigerator
Freezing
Cold chain
Food supply
Food processing
Absorption
system
Medical & Biological fields
Industrial process
Data center
Clean room
House
Adsorption
system
Sustainable society
Drying
1 Industrial fields
Automobile
Hospital
Office
Building
Air-Conditioning
Cooling
Hot water
Heat Pump
Combustion
Heating
3
Background
Need to Build Low-Carbon Society
• Montreal Protocol (1987)
• Phase out of ozone depletion gasses, CFCs, HCFCs, etc.
• Developed countries
• CFC: 1995 (Phase out was completed in Japan)
• HCFC: 2020 (Production is being reduced)
• Developing countries
• CFC: Phase out in 2010 (start from 1999)
• HCFC: Phase out in 2040 (start from 2016)
• Alternative refrigerants: HFCs (R134a, R410A, etc. )
• Successful replacement
• Kyoto Protocol (1997)
• Reduction of greenhouse gases, CO2, HFCs(R32, R410A, etc.), etc.
• Developed countries
• Average reduction of 5.2% reduction from 1990 level by the year 2012
• 6% reduction for Japan, F-gas regulation in Europe
• IPCC Fifth Assessment Report: Sep. 2013 ~ Oct. 2014
Motivation
Next Generation Refrigerants
•
Natural refrigerants
•
•
Tentative continuous use of HFCs for midway
•
Refrigerant management
Refrigerant leakage, Refrigerant tracking, Engineers skill, …
•
R32 is now being promoted.
•
•
Low GWP synthetic refrigerants: HFOs
•
•
•
HC in refrigerator, CO2 in HP water heater, NH3 in industrial …
R1234yf for mobile AC, R1234ze(E) for turbo chiller,
R1234ze(Z) for heat pump in high temperature range …
other HFOs, R1234ye, R1233zd, R1243zf, R1225
Study on Properties, Heat transfer , Drop-in test, …
Refrigerant mixtures
•
•
•
Limitation of pure refrigerant properties
Suitable properties such as pressure, flammability, …
Property measurements, Cycle simulation, Drop-in test, …
Introduction
by Eiji HIHARA, University of Tokyo
Summary of the proposed regulation of HFCs
Revise the Montreal Protocol (US, Canada, Mexico)
 Restriction of production and sales of HFCs
EU protocol on mobile air-conditioning refrigerants
 GWP < 150 from January 1, 2011
F-gas Regulation for stationary air-conditioners
 Reducing leakage, Proper management, Instruction courses,
Labeling, Report by producers/importers/exporters
Proposed phasedown schedule of HFCs
Proposal by US, Canada, Mexico
Developing countries
Developed countries
Proposal by EU Commission
Emissions of HFCs in Japan -present situationTotal CO2 emission of HFCs[million-t]
others
Ref. & AC
million-t CO2
Small refrigerator
Large refrigerator
In dispose
Medium refrigerator
Package AC for building
Other business use
Room AC
In use
Show case (split-type)
Leakage
Trend in mildly flammable refrigerants
Environment-friendly refrigerants
 Zero ODP (ozone depletion potential)
 Low GWP (global warming potential)
Refrigerants for room and package air-conditioners
HFOs
 R1234fy
 R1234ze(E)
ODP=0, GWP=4
ODP=0, GWP=6
HFCs
Mildly flammable
rank 2L on ASHRAE Standard 34
 R32
ODP=0, GWP=675
(note: most of other HFCs: GWP>1000)
Requirement of risk assessment
Methodology of risk assessment
Burning characteristics of flammable refrigerants
Mechanism of ignition
Probability of ignition
= (Leakage) X (High concentration) X (Ignition source) X (Low air velocity)
Research on safety of mildly flammable refrigerants
By
Eiji HIHARA, Tatsuhito HATTORI, Makoto ITO
University of Tokyo
 Leakage of mildly flammable refrigerants
Simulation conditions of leakage of refrigerants
Leakage scenarios
Room air conditioners (RAC)
Variable refrigerant flow air conditioning
systems for building (VRF)
Simulation results of leakage of refrigerants
Leak of R32 from wall-mounted indoor unit of RAC
Simulation model
Simulation result
isosurface of concentration
at LFL (13.3 vol%)
Leakage scenario
No
Position of leakage
Refrigerant
Amount
[g]
Flow rate
[g/min]
1
Wall-mounted indoor unit
R32
1000
250
Combustion does not occur
if the ignition source does not
exist inside the indoor unit.
Simulation results of leakage of refrigerants
Leak of R32 from floor-mounted indoor unit of RAC
Simulation model
Simulation result
isosurface of concentration
at LFL (13.3 vol%)
Leakage scenario
No
Position of leakage
Refrigerant
Amount
[g]
Flow rate
[g/min]
9
Floor-mounted indoor unit
R32
1000
250
The leakage of flammable refrigerants
from a floor-mounted indoor unit has a
high risk of combustion.
Simulation results of leakage of refrigerants
Leak of R32 from outdoor unit of RAC in balcony
Simulation model
Simulation result
isosurface of concentration
at LFL (13.3 vol%)
Leakage scenario
No
Position of leakage
Refrigerant
Amount
[g]
Flow rate
[g/min]
11
Outdoor unit
R32
1000
250
The leakage of flammable refrigerants
from an outdoor unit has a high risk of
combustion.
Note: Drains and under cuts shorten the
presence of the gas.
Simulation results of leakage of refrigerants
Leak of R32 from ceiling-mounted indoor unit of VRF
Simulation model
Simulation result
isosurface of concentration
at LFL (13.3 vol%)
Leakage scenario
No
Refrigerant
Amount
[kg]
Flow rate
[kg/h]
Forced air
[m3/h]
Air vent
3
R32
26.3
10
0
exists
A combustion gas region only exists just
below the air outlet and the suction of
the VRF, even if the entire quantity of
refrigerant is discharged.
Simulation results of leakage of refrigerants
Time variation of concentration of R32
Research and development of low-GWP refrigerants
suitable for heat pump system
By
Shigeru KOYAMA, Kyushu University
Yukihiro HIGASHI, Iwaki Meisei University
Akio MIYARA, Saga University
Ryo AKASAKA, Kyushu Sangyo University






Flammability
Toxicity
Thermodynamic properties
Transport properties
Heat transfer
Heat pump cycle
Drop-in experiments of pure HFO and HFO+HFC
Drop-in experiments of pure HFO and HFO+HFC
Drop-in experiments of pure HFO and HFO+HFC

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