Presentation on theme: "Risk Assessment of Mildly Flammable Refrigerants 2012 Progress Report The Japan Society of Refrigerating and Air-Conditioning (JSRAE) November 22, 2013."— Presentation transcript:
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 Collaboration of JSRAE and SAME Okinawa Chapter
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 Contents of the report File can be downloaded from
Combustion Absorption system Adsorption system Vapor compression system 1 Food supply Medical & Biological fields Refrigerating Air-Conditioning Heat Pump Comfortable life Cold storage Cold chain Drying Food processing House Building Office Cooling Heating Freezing Automobile Industrial process Hot water Survive Sustainable society Refrigerator Refrigerator car Hospital Industrial fields 3 Data center Clean room Background Necessary & Indispensable Technology
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, CO 2, HFCs(R32, R410A, etc.), etc. Developed countries Average reduction of 5.2% reduction from 1990 level by the year % reduction for Japan, F-gas regulation in Europe IPCC Fifth Assessment Report: Sep ~ Oct. 2014
Natural refrigerants HC in refrigerator, CO 2 in HP water heater, NH 3 in industrial … 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 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, … Motivation Next Generation Refrigerants
Introduction by Eiji HIHARA, University of Tokyo Summary of the proposed regulation 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 Revise the Montreal Protocol (US, Canada, Mexico) Restriction of production and sales of HFCs
Proposed phasedown schedule of HFCs Proposal by EU Commission Proposal by US, Canada, Mexico Developed countries Developing countries
Emissions of HFCs in Japan -present situation- Total CO 2 emission of HFCs[million-t] others Ref. & AC In dispose In use Small refrigerator Large refrigerator Medium refrigerator Package AC for building Other business use Room AC Show case (split-type) million-t CO 2 Leakage
Trend in mildly flammable refrigerants Environment-friendly refrigerants Zero ODP (ozone depletion potential) Low GWP (global warming potential) HFOs R1234fyODP=0, GWP=4 R1234ze(E) ODP=0, GWP=6 HFCs R32 ODP=0, GWP=675 (note: most of other HFCs: GWP>1000) Requirement of risk assessment Mildly flammable rank 2L on ASHRAE Standard 34 Refrigerants for room and package air-conditioners
Methodology of risk assessment Burning characteristics of flammable refrigerantsMechanism 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 Room air conditioners (RAC) Leakage scenarios Variable refrigerant flow air conditioning systems for building (VRF)
Simulation results of leakage of refrigerants Simulation model Leak of R32 from wall-mounted indoor unit of RAC Simulation result isosurface of concentration at LFL (13.3 vol%) NoPosition of leakageRefrigerant Amount [g] Flow rate [g/min] 1Wall-mounted indoor unitR Leakage scenario Combustion does not occur if the ignition source does not exist inside the indoor unit.
Simulation results of leakage of refrigerants Simulation model Leak of R32 from floor-mounted indoor unit of RAC Simulation result isosurface of concentration at LFL (13.3 vol%) NoPosition of leakageRefrigerant Amount [g] Flow rate [g/min] 9Floor-mounted indoor unitR Leakage scenario The leakage of flammable refrigerants from a floor-mounted indoor unit has a high risk of combustion.
Simulation results of leakage of refrigerants Simulation model Leak of R32 from outdoor unit of RAC in balcony Simulation result isosurface of concentration at LFL (13.3 vol%) NoPosition of leakageRefrigerant Amount [g] Flow rate [g/min] 11Outdoor unitR Leakage scenario 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 Simulation model Leak of R32 from ceiling-mounted indoor unit of VRF Simulation result isosurface of concentration at LFL (13.3 vol%) NoRefrigerant Amount [kg] Flow rate [kg/h] Forced air [m 3 /h] Air vent 3R exists Leakage scenario 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