RESEARCH ON NAURAL REFRIGERANS IN JAPAN WASEDA UNIVERSIY Kiyoshi SAIO
INRODUCION In Japan, we have the highest level technologies for natural refrigerant use in the world. CO2 Residential heat pump water heater Commercial heat pump water heater Car air-conditioner Show case Bending machine NH3 Industrial refrigerator HC refrigerator for residential use Water Centrifugal chiller Absorption chiller Absorption heat transformer Air Air cycle refrigerator Desiccant air-conditioning CO2 Residential heat pump CO2 Commercial heat pump CO2 Car air-con. CO2 Show case CO2 Bending NH3 industrial refrigerator HC residential refrigerator Air cycle ref. H2O Centrifugal chiller Absorption chiller Development of these systems are supported by fundamental R&Ds Heat and mass transfer New devices development -heat exchanger, compressor, ejector System technology system development, simulation, control.. 2 Absorption heat transformer Desiccant air-conditioner
FUNDAMENAL RESEARCH Fundamental research Heat transfer Heat transfer coefficient kw/m 2 K Heat transfer coefficient kw/m 2 K 4 3 2.2.4.6.8 1 Vapor quality 4 3 2 D in =.mm D in = 3.mm sat : -.39 ~ -.8 Upper portion Under portion sat : -3.7 ~ -1.8 Upper portion Under portion.2.4.6.8 1 Vapor quality Fig. Comparison of CO 2 evaporating heat transfer for smooth tube and Micro-fin tube 2mm Chaobin Dang, Nobori Haraguchi, Eiji Hihara, international journal of refrigeration 33(2) 6 663 Fig. Gas cooler heat transfer coefficient Effect of oil contamination, 1,2 mm Chaobin Dang, Koji Iino, Ken Fukuoka, Eiji Hihara, International journal of refrigeration 33(27) 724 731 3 Heat transfer coefficient kw/m 2 K 4 3 2 D in = 1.mm sat : -4. ~ -1.66 Upper portion U n d e r p o r t i o n.2.4.6.8 1 Vapor quality Fig. Ammonia mini channel Evaporating heat transfer
NEW DEVICE DEVELOPMEN Comp. Scroll wo stage Swing Rotary Combi.. of Rotary and scroll CO2-Water Heat ex. Piping embedded 水配管 ( ツイスト管 ) 冷媒配管 Ejector Expander Ejector Expander 4
NEW SYSEM~ABSORPION HEA RANSFORMER Refrigerant Separator H Absorber Steam Separator SV Second stage EH AH S Steam.4.3 Evaporator Absorbing Evaporator COP.2 Water RP Condenser EL C Generator AL GL SP Hot Water Hot Water Feed Water Fig. Double stage absorption heat transformer (National project by NEDO) Pressure P kpa.1 AH EL C 1 7 8 8 9 9 Hot water inlet temperature o HW C Fig. Results With this cycle, 18 steam can be produced fro 9 oc waste hot water.
NEW SYSEM~ Evaluation of CO 2 refrigeration system for convenience store Evaporator Flow Compressor Gas cooler Compressor Compressor 凝縮器 Condenser Evaporator 蒸発器 凝縮器 Condenser Higher pressure side cycle Lower pressure side cycle Evaporator 蒸発器 Showcase Fig. Cascade refrigeration system SANDEN National project by NEDO 6
NEW SYSEM ~CENRIFUGAL CHILLER Feature Water is refrigerant New compressor for water refrigerant is developed. COP.1 All most the same size with conventional system. Oil free capa. USR Fig. Water refrigerant centrifugal chiller Produced by Kawasaki 山内正史, 水を冷媒としたターボ冷凍機, 日本冷凍空調学界, 平成 24 年度最新の冷媒と利用技術の動向, セミナー資料 7
空調機 NEW SYSEM~CO 2 HEA RANSPORAION Heat transportation system whose refrigerant is CO 2 Conventional Server rack (blade server) Hot spot Objective Spot cooling inside unit 4 verall air onditioner Supply air 2 機Ceiling Overall air conditioner Ceiling Fig. Conventional data center (Overall air-conditioning method) Floor Hot spot occurs some server stops Fan power increases Energy use emp. of circulated air decrease increase Fig. Spot- air conditioning system (combining spot cooling unit with overall air-conditioner) Floor 8
NEW SYSEM~CO 2 HEA RANSPORAION Chiller Spot cooling unit Heat transportation system Heat transfer flow rate in evaporator Q kw Latent heat ratio in evaporator γ - 8 6 4 2 2 1. 1. Spot cooling system consists of chiller heat transportation system spot cooling unit o realize effective spot cooling method, heat transportation system is very important. his system has very good potential with higher performance because CO 2 is good transport medium. Rack outlet air temp. 3 o C Exp. Sim. 3 o C Exp. Sim. 2 o C Exp. Sim. 2 o C Exp. Sim. 2 4 6 8 Working fluid mass flow rate G b kg/min 9 Pressure drop in Evaporation ΔP kpa air temp. in evaporator outlet o C 4 3 2 4 3 2 2 4 6 8 Working fluid mass flow rate G b kg/min Fig. Results Evaporation pressure P MPa Heat transpotation performance factor P f 7 6 4 2 1 2 4 6 8 Working fluid mass flow rate G b kg/min
NEW SYSEM ~HC EJECOR SOLAR COOLING 139 144 Ejector.6..4 Ammonia n-butane Iso-Butane R134a R24fa R22 HFO1234yf HFO1234ze COP.3.2.1 28 3 32 34 36 38 4 Condensation temperature Fig. Ejector heat pump system Fig. Simulation results his system is ejector heat pump system without compressor. his system can be driven by solar energy. he best refrigerant for this system is ammonia, then HC. We are going to realize this system with natural refrigerant.
SIMULAION ECH. ~HEA EXCHNGER L 7 P Ref. inlet Air inlet Ref. outlet P Air outlet LF,t LF,Pi emperature 6 4 Sim. Exp. 3 4 8 12 16 2 24 28 Number Fig. Results of condenser We develop the system simulator Energy flow +M. his simulator is user friendly because this uses GUI. his simulator can calculate performance of heat exchanger with high precision. Fig. System flow 11
SIMULAION ECH. ~SYSEM1 Exp. Eva. Cond. Controller Comp. Accum. Rotational speed n COM1 rps Valve1 opening pulse Valve2 opening pulse Valve3 opening pulse Valve4 opening pulse Pressure P COM O kpa Pressure P COM I kpa 12 8 4 6 4 2 6 4 2 6 4 2 6 4 2 3 2 2 1-2 2 4 6 8 ime t s Compressor input kw capacity Q EVA1 kw capacity Q EVA2 kw capacity Q EVA3 kw capacity Q EVA4 kw capacity kw COP 6 8 24 3 2-2 2 4 6 8 ime t s Fig. Simulation results For dynamics of comp. cycle Fig. Simulator Energy flow+m With this simulator, we can change the refrigerant easily. We can estimate every performance of the system that uses different refrigerant. 12
SIMULAION ECH. ~SYSEM2 HC drop-in test. Fig. Using R4a system for drop in test able heoretical compression cycle R 4A HC 6a (Original) (Drop-in) Evaporation temperature,. Condensation temperature, 4. Sub cooled temperature,. Super heat temperature,. Adiabatic efficiency, 1. - heoretical COP, 6.4 7.13 - Refrigerant flow rate per a unit.61.37 cooling capacity, kg/(s kw) HC is very good refrigerant theoretically. But only with drop in, the performance is getting worse. We are now trying to optimize the air-conditioner with HC by simulation. 13 able Exp. & Sim. result (Rated cooling) Refrigerant capacity, kw Electric input, kw COP, - R 4A (Original) HC 6a (Drop-in) Exp. Sim. Exp. Sim. 2.84 2.83.887.877.69 2.68.177.173 4.11 4.13..7 able Exp. & sim. result (Half load cooling) Refrigerant R 4A (Original) HC 6a (Drop-in) Exp. Sim. Exp. Sim. capacity, kw 1.36 1.47.37.43 Electric input, kw.2.26.836.96 8 COP, -.42.62 4.43 4.4
SIMULAION ECH. ~SIMULAOR デモンストレーション 14