P-h Chart for R134a (SI Units) - Syracuse University

1 1 Principles of RefrigerationMAE 554 Professor H. Ezzat KhalifaSyracuse UniversityP-h Chart for R134a (SI Units) 2 Psychrometric Chart (ASHRAE)Psychrometric ProcessesCoolHeatHumidifyDehumidifyCool & DehumidifyAir Conditioning Systems Cool & Dehumidify Air3A/C System Psychrometric ProcessesRoom Condition LineCoil temperature must be cooler than room dew point (DP) to dehumidify the airCoil InletRoom Return AirOutdoor AirRoom DPCoil ExitReversed Carnot Temperature - TC, Cycle PerformanceSat Cond T, CReversed Carnot Vapor Compression CyclesTTCTH5 Reversed Rankine Vapor Compression CyclesTTCTHS uperheat HornIncreased WorkIdeal Practical Vapor Compression CyclesTTCTHS uperheat HornIncreased WorkThrottling Lossin RefrigerationThrottling LossIn Work61324 Simple Vapor Compression CycleSingle-Stage Vapor Compression Cycle hW hEhPPEPC TSC hWo TSH7 Ideal VCC Performance Sat. Temp., CCOPC0510152025 Capacity, QCond. Sat. Temp., CR22 Ideal VCC10 CFM CompressorComparison of Ideal VCC with Carnot Sat.

2 Temp., CRelative Sat. Temp., C8hPPEPCPSPD11b1a2d1c324P-h Diagram for Real Vapor Compression CycleEffect of the Gas Specific Heat Ratio, 912346785 Two-Stage VCC with Flash Economizer hEhPPEPC TSC hW1 TSH12345678 hW2 PIP-h Diagram for 2-Stage VCC with Flash Economizer10123456785 Two-Stage VCC with Subcooler Economizer hEhPPEPC TSC hW1 TSH12345678 hW2 PIP-h Diagram for 2-Stage VCC with 0 1020304050 Intermediate Sat. Temp., CCOPC, COPCrCOPCCOPCrGeometric-MeanIntermediate Optimum Intermediate Temperature for 2-Stage Sat. Temp., CCOPC35/COP 150/COP 135/COP 250/COP 2 Cond. Sat. Temp., CR22 Ideal VCCC omparison of Two-Stage and Single-Stage of StagesRelative COPC and CapaityRel. COPRel. CapacityR22 Ideal VCCP erformance of Multi-stage VCCs14 Cascade SystemHigh-Temperature RefrigerantLow-Temperature Refrigerant13 Desirable Characteristics of Refrigerants Thermally stable Safe (toxicity and flammability) Low cost and widely available Compatible with materials of construction High performance High latent heat Low compression superheat Low throttling losses High heat transfer properties Environmentally benign (ODP and GWP)Refrigerant ClassificationRefrigerantsMixturesPureZe otropesAzeotropesR502R507R410A*R404A*R40 7 CNaturalCFCHCFCHFCA mmoniaPropaneR12R114R11R22R123R134aR32R1 25R143aIso-ButaneR290-R600a*Near-Azeotro pesCO2 Used in or considered for RefrigerationPropane/Iso-Butane14 Mixture Phase Fraction, xSat.

3 TemperatureTsatLiquid Mole-FractionVapor Mole-FractionP1P2 Mixture Phase Fraction, xSat. TemperatureTsatLiquid Mole-FractionVapor Mole-FractionP1P2 Azeotrope15 NIST Refrigerant PropertiesASHRAE Refrigerant Safety ClassificationB3R1140A3R170,R290, R600a,R1150 High FlammabilityB2NH3A2R32, R142b, R143a, R152aLow FlammabilityB1R123, R764, R21A1R11, R12, R22, R125, R134a , R407C, R507, R404A, R410A, R744No FlammabilityHigh ToxicityLow/No ToxicityRefrigerants marked in Red are ozone depleting substances that are no longer used in new marked in Green are natural refrigerants that have low GWP,as well as no : Methane GroupRefrigerants: Ethane Group17 ODP and GWP for Various RefrigerantsRefrigerantODPGWPR efrigerantODPGWPCFC-11 CFC-12 HFC-134 CFC-13 N/AN/AHFC-134a HCFC-22 HFC-143a HFC-23 N/A HFC-152a HFC-32 R500 CFC-113 R502 CFC-114 R503 N/A N/A HCFC-123 R410A HCFC-123a R507 HCFC-124 ODP (Ozone Depletion Potential), and GWP (Greenhouse Warming Potential) are calculated relative to CFC Comparison( )

4 Means reference valueRefrigerantCO2R12R22R134aR404AR410A C3H8NH3 Natural?YesNoNoNoNoNoYesYesFlammable?NoN oNoNoNoNoYesYesToxic?NoNoNoNoNoNoNoYesRe lative ( ) ( ) Temp.(F)88234205214163158206270P @ 70F (psia)8528513686165216125129 ODP (100yr)( )710015001300375017303018 Refrigerant Pressure-Capacity Difference @ ARI [psi]Volumetric Capacity @ ARI [Ton/cfm]Best FitR123R11R245faR114R600aR12R134aR290R22 R407CR717R507R410AR22NH3R404A/R507 PropaneR407CR410AR134aR22 & its near neighborsComparison of Simple Cycle Relative to R22 ARICHEER19 Relative ARI Capacity [Same Displacement] relative to R22 Relative compressor Displacement [Same Capacity] relative to R2220 Low Temperature Capacity ComparisonSCT=130F; SH=20F; SC=15F; No LSHX; No -40 -30 -20 -10010 20 3040 50 Saturated Evaporator Temperature [F]Capacity Relative to ARIR22R507R134aR410 ALow Temperature EER -40 -30 -20 -10010 20 3040 50 Saturated Evaporator Temperature [F]EER Relative to R22 @ ARIR22R507R134aR410 ASCT=130F; SH=20F; SC=15F; No LSHX.

5 No Quench21 Discharge Superheat Comparison050100150200250300-50 -40 -30 -20 -1001020304050 Saturated Evaporator Temperature [F]Discharge Suoerhear [F]R22R507R134aR410 ASCT=130F; SH=20F; SC=15F; No LSHX; No QuenchTotal Equivalent Warming Impact (TEWI)Medium Temperature RefrigerationFrom DoE's ORNL Report, 199722 Fluid Comparison - R134a vs. R744 (CO2)Region of Operational InterestRegion of Operational InterestR744 (CO2)R134aR134aR744 Critical Point214 F88 FLow Pressure10-50 psi110 - 500 psiHigh Pressure100-250 psi750-2000 psiOther CO2 Properties:High throttling losses Solid CO2(Dry Ice) at -80F (70 psi)Transcritical Cycle (typical)Much Higher heat transfer potential (2-3x)Temperature glide on heat rejection HXRefrigerant-Lubricant Viscosity23 Vapor CompressorsClassification of Vapor CompressorsPositive Displacement Machines [PD]: Reciprocating piston , Rolling piston , Scroll, Screw, Sliding Vane ..Rotodynamic (Turbo) Machines [RD]: Radial, Mixed-flow Centrifugal; Single and Multi-stage24 Positive Displacement Vapor CompressorsCompressor Application [HVAC]Scroll [HVAC]H Recip [HVAC]SH Recip [HVAC]Screw [HVAC]Centrifugal [HVAC]ARI Capacity, Tons25 Positive Displacement CompressorsPiston (Reciprocating)26 Comparison of P-V DiagramsPressureScroll/Screw (AC & Refrig.)

6 Volume DisplacementClearance VolumeRecip. ACRecip. to 60% Up to 60% More CapacityMore CapacityPiston compressor Volumetric 102030405060 Pressure RatioTheoretical Volumeteric = piston (Rotary) compressor PumpTypical Rolling piston CompressorASHRAE Handbook of Systems and Equipment, 200428 Hermetic Scroll CompressorScroll Compressor29 Scroll compressor OperationScroll Operation (DTU) Typical Scroll compressor PerformanceASHRAE Handbook of Systems and Equipment, 200430 Twin Screw (Lysholm) CompressorSingle Screw CompressorASHRAE Handbook of Systems and Equipment, 200431 Typical Screw compressor PerformanceASHRAE Handbook of Systems and Equipment, 2004 Over/Under-compression Loss0%20%40%60%80%100% Discharge Pressure (Pd/Pd*)Percentage Over/Under-compression CompressorsEfficiency 102030405060708090M ale Rotor T ip Speed [m/s]Relative EfficiencyLeakage LossesFlow & Viscous LossesPump EfficiencyClose leakage gaps & reduce oil injectionClose leakage gaps & reduce oil injectionSliding Vane Compressor33 Centrifugal CompressorsCentrifugal Compressor34 Typical Centrifugal compressor ImpellerASHRAE Handbook of Systems and Equipment, 2004Ns-DsDiagram for Single-Stage CompressorsFrom O.

7 E. Balje: Turbomachines - A Guide to Design Selection and Theory, Wiley, NY, '81352-Stage Centrifugal CompressorASHRAE Handbook of Systems and Equipment, 2004 Polytropic RatioIsentropic Efficiency p = ; = Centrifugal compressor PerformanceASHRAE Handbook of Systems and Equipment, 2004 IGV Control Fixed SpeedVariable-Speed ControlCentrifugal Chiller Part-Load PerformanceASHRAE Handbook of Systems and Equipment, 200437 Comparison of Chiller CompressorsASHRAE Handbook of Systems and Equipment, 2004 Expansion Devices38 Short Restrictor Expansion DeviceASHRAE Handbook of Refrigeration, 2004 Thermostatic Expansion ValveASHRAE Handbook of Refrigeration, 200439 Constant-Pressure Expansion ValveASHRAE Handbook of Refrigeration, 2004 Float-controlled Expansion ValveASHRAE Handbook of Refrigeration, 200440 Thermally Activated Heat Pump ConceptASHRAE Handbook of Refrigeration, 2004 Single-Effect LiBr-H2O Absorption Cycle164"7324'5 Solution HXCondenserEvaporatorAbsorberGeneratorPu mp41 Practical Configuration of LiBr-H2O SystemASHRAE Handbook of Refrigeration, 2004 Mixture Phase Fraction, xSat.

8 TemperatureTsatLiquid Mole-FractionVapor Mole-FractionP1P242 Single-Effect LiBr-H2O Cycle Duhring DiagramTPCrystallizationPEPCPure H2O; x=0x=xsx=xwTGTC~TATE1, 763254', 4"Double-Effect LiBr-H2O Absorption Cycle [1]3'196107'562 CondenserEvaporatorAbsorberGenerator 1 Pump7"Solution HX3'8 PumpSolution HXGenerator 24'4384"43 Double-Effect LiBr-H2O Absorption Cycle [2]1109"12324'6'CondenserEvaporatorAbsor berGenerator 1 Pump4"3'549'8'86 Solution HXGenerator 2 Single-Effect LiBr-H2O Cycle Duhring DiagramTPCrystallizationPEPCPure H2O; x=0x=xsx=xwTGTC~TATE1, 873254, 644 Pumpless Aqua-Ammonia SystemASHRAE Handbook of Refrigeration, 2004 Bubble PumpSimple and Regenerative Reversed Brayton CycleST2 3 6, 1 5432145 Regenerative Air CoolerAmbient airPowerSimple Air Cycle PerformanceTa = 35 C; R= ; E = ; C= ; P/P = ; TA= 10 Pressure Temp. C46 Regenerative Air Cycle Pressure Temp. CTa = 35 C; R= ; E = ; C= ; P/P = ; TA= 10 CComparison of Air Liquefaction Cycles020004000600080001000012000 Revrsible(Ideal)LindeLinde + VC Precooler (-45 C)Dual-PressureLindeDual-PressureLinde + VCPrecoolerClaudekJ/kg Liquid Air47 Rotary Magnetic Refrigerator