Presentation on theme: "Risk Assessment of Mildly Flammable Refrigerants"— Presentation transcript:
1Risk Assessment of Mildly Flammable Refrigerants Collaboration of JSRAE and SAME Okinawa ChapterRisk Assessment of Mildly Flammable Refrigerants2012 Progress ReportThe Japan Society of Refrigerating and Air-Conditioning (JSRAE)November 22, 2013Akio MIYARASaga UniversityDepartment of Mechanical Engineering
2Contents of the report1 Introduction2 Legal issues with mildly flammable refrigerant Explanation of high pressure gas safety law and legal issues with mildly flammable refrigerant Current international trends regarding refrigerant3 Research on safety of mildly flammable refrigerants Progress of the University of Tokyo Research and development of low-GWP refrigerants suited to heat pump systems Physical hazard evaluation of A2L-class refrigerants using several types of conceivable accident scenarios Progress report by research Institute for Innovation in Sustainable Chemistry, AIST Physical hazard evaluation on explosion and combustion of A2L class refrigerants4 Progress of the Japan Refrigeration and Air Conditioning Industry Association (JRAIA) 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 VRF risk assessment SWG: The 1st risk assessment of VRF system with A2L refrigerant and future Chiller risk assessment SWG: Risk assessments policy of the chiller and guideline planning taking IEC60079 into consideration5 Deregulation activities in Japan for the introduction of mobile air conditioning refrigerant R1234yfFile can be downloaded from “ ”
4Background Need to Build Low-Carbon Society Montreal Protocol (1987)Phase out of ozone depletion gasses, CFCs, HCFCs, etc.Developed countriesCFC: (Phase out was completed in Japan)HCFC: 2020 (Production is being reduced)Developing countriesCFC: Phase out in 2010 (start from 1999)HCFC: Phase out in 2040 (start from 2016)Alternative refrigerants: HFCs (R134a, R410A, etc. )Successful replacementKyoto Protocol (1997)Reduction of greenhouse gases, CO2, HFCs(R32, R410A, etc.), etc.Average reduction of 5.2% reduction from 1990 level by the year 20126% reduction for Japan, F-gas regulation in EuropeIPCC Fifth Assessment Report: Sep ~ Oct. 2014
5Motivation Next Generation Refrigerants Natural refrigerantsHC in refrigerator, CO2 in HP water heater, NH3 in industrial …Tentative continuous use of HFCs for midwayRefrigerant managementRefrigerant leakage, Refrigerant tracking, Engineers skill, …R32 is now being promoted.Low GWP synthetic refrigerants: HFOsR1234yf for mobile AC, R1234ze(E) for turbo chiller, R1234ze(Z) for heat pump in high temperature range … other HFOs, R1234ye, R1233zd, R1243zf, R1225Study on Properties, Heat transfer , Drop-in test, …Refrigerant mixturesLimitation of pure refrigerant propertiesSuitable properties such as pressure, flammability, …Property measurements, Cycle simulation, Drop-in test, …
6Summary of the proposed regulation of HFCs Introductionby Eiji HIHARA, University of TokyoSummary of the proposed regulation of HFCsEU protocol on mobile air-conditioning refrigerantsGWP < 150 from January 1, 2011Revise the Montreal Protocol (US, Canada, Mexico)Restriction of production and sales of HFCsF-gas Regulation for stationary air-conditionersReducing leakage, Proper management, Instruction courses, Labeling, Report by producers/importers/exporters
7Proposed phasedown schedule of HFCs Proposal by US, Canada, MexicoDeveloping countriesDeveloped countriesProposal by EU Commission
8Emissions of HFCs in Japan -present situation- Total CO2 emission of HFCs[million-t]othersRef. & ACIn disposeIn useSmall refrigeratorLarge refrigeratorMedium refrigeratorPackage AC for buildingOther business useRoom ACShow case (split-type)million-t CO2Leakage
9Trend in mildly flammable refrigerants Environment-friendly refrigerantsZero ODP (ozone depletion potential)Low GWP (global warming potential)Refrigerants for room and package air-conditionersHFOsR1234fy ODP=0, GWP=4R1234ze(E) ODP=0, GWP=6HFCsR ODP=0, GWP=675 (note: most of other HFCs: GWP>1000)Mildly flammablerank 2L on ASHRAE Standard 34Requirement of risk assessment
10Methodology of risk assessment Burning characteristics of flammable refrigerantsMechanism of ignitionProbability of ignition= (Leakage) X (High concentration) X (Ignition source) X (Low air velocity)
11Research on safety of mildly flammable refrigerants ByEiji HIHARA, Tatsuhito HATTORI, Makoto ITOUniversity of TokyoLeakage of mildly flammable refrigerants
12Simulation conditions of leakage of refrigerants Leakage scenariosVariable refrigerant flow air conditioning systems for building (VRF)Room air conditioners (RAC)
13Leak of R32 from wall-mounted indoor unit of RAC Simulation results of leakage of refrigerantsLeak of R32 from wall-mounted indoor unit of RACSimulation modelSimulation resultisosurface of concentration at LFL (13.3 vol%)Leakage scenarioNoPosition of leakageRefrigerantAmount[g]Flow rate[g/min]1Wall-mounted indoor unitR321000250Combustion does not occurif the ignition source does not exist inside the indoor unit.
14Floor-mounted indoor unit Simulation results of leakage of refrigerantsLeak of R32 from floor-mounted indoor unit of RACSimulation modelSimulation resultisosurface of concentration at LFL (13.3 vol%)Leakage scenarioNoPosition of leakageRefrigerantAmount[g]Flow rate[g/min]9Floor-mounted indoor unitR321000250The leakage of flammable refrigerants from a floor-mounted indoor unit has a high risk of combustion.
15Leak of R32 from outdoor unit of RAC in balcony Simulation results of leakage of refrigerantsLeak of R32 from outdoor unit of RAC in balconySimulation modelSimulation resultisosurface of concentration at LFL (13.3 vol%)Leakage scenarioThe 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.NoPosition of leakageRefrigerantAmount[g]Flow rate[g/min]11Outdoor unitR321000250
16Leak of R32 from ceiling-mounted indoor unit of VRF Simulation results of leakage of refrigerantsLeak of R32 from ceiling-mounted indoor unit of VRFSimulation modelSimulation resultisosurface of concentration at LFL (13.3 vol%)Leakage scenarioNoRefrigerantAmount[kg]Flow rate[kg/h]Forced air[m3/h]Air vent3R3226.310existsA 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.
17Time variation of concentration of R32 Simulation results of leakage of refrigerantsTime variation of concentration of R32
18Research and development of low-GWP refrigerants suitable for heat pump system ByShigeru KOYAMA, Kyushu UniversityYukihiro HIGASHI, Iwaki Meisei UniversityAkio MIYARA, Saga UniversityRyo AKASAKA, Kyushu Sangyo UniversityFlammabilityToxicityThermodynamic propertiesTransport propertiesHeat transferHeat pump cycle