Chapter-15 Centrifugal Compressors And Chillers - Acmv
႔ Chapter-15 Centrifugal Compressors and Chillers Chapter-15 Centrifugal Compressors and Chillers ၁၅.၁ Dynamic Compressors Centrifugal compressor dynamic compressor compressor Centrifugal gas ၏ velocity ႔ pump ၌ (eye) blade ႔ centrifugal force Suction gas ႔ (axial direction) tangent direction gas ႔ (energy) (density) (density) rotor ၏ tip speed gas ၏ (velocity) working condition Centrifugal compressor speed rotor ၏ ၏ design performance (density) gas 300 m/s tip (speed) single-stage chiller ၏ impeller (diameter) impeller (2 m) tip speed (shaft) impeller ႇ ႇ (shaft) Air-conditioning compressor ၏ rotor speed 10,000 rev/min Gas single-stage centrifugal ႔ ႔ (compress) 2 m (6 ft) - (shaft) impeller compression (ammonia) refrigerant centrifugal compressor (၇) (seven compression stages) T centrifugal compressor centrifugal compressor ၏ capacity compressor ၏ capacity 7,000 kW(2,000RT) Semi-hermetic open drive compressor ၏ capacity 15-1
႔ 21,000 kW Main bearing (oil free) lubrication compressor refrigerant R134a Centrifugal compressor R123 ႔ ၁၅-၁ Model YMC² Magnetic Centrifugal ၁၅-၂ Model YK Single Centrifugal Compressor ၁၅-၃ Model YD (Dual Centrifugal Compressor) ၁၅-၄ Model CYK (Compound Compressor) Centrifugal compressor ၏ pumping characteristic positive displacement compressor Centrifugal compressor gas compressor ႔ ၏ performance capacity (reverse flow) condensing condition Centrifugal Head pressure Coefficient of Performance(COP) efficiency Capacity rated capacity impeller ၏ (blade angle) (pressure) impeller ႔ Condenser system centrifugal chiller ႔ Full flow ၏ 10–15% Variable Speed Drive centrifugal chiller V centrifugal compressor (၁၅-၅) Centrifugal compressor circular path compressor ၏ (centrifugal force refrigerating (compress) ႔ Compressor ႔ Radial blade (impeller) blade Steam turbine ႔ gas turbine engine ႔ main bearing compressor ၏ (၁၅-၁၂) two stage centrifugal compressor Stage 15-2
႔ Chapter-15 Centrifugal Compressors and Chillers impeller impeller ႇ (၁၅-၅) ႔ impeller ႔ impeller ႔ compressor ၏ hermetic centrifugal Compressor ၏ compressor shaft stator Rotor key Key gas velocity ႔ trapping pocket ၁၅.၂ Centrifugal Compressors chiller flow positive displacement compressor kW 20 MW range (100RT centrifugal compressor 5,600RT) capacity centrifugal chiller Centrifugal compressor R-123 R-22 multistage refrigeration system R-134a Multistage centrifugal compressor Compressor centrifugal compressor cast iron (discharge pressure) (ammonia) 40 bar cast steel casings ႔ ႔ refrigerant centrifugal compressor single stage multistage open semi-hermetic Centrifugal compressor 350 ႔ ႔ hermetic compression ratio per impeller ႔ multistage compressor ၏ operating principle Centrifugal centrifugal pump Labelled 3 - showing inlet guide vanes Labelled 4 - moveable wall diffuser ၁၅-၅ Centrifugal compressor with variable geometry, showing inlet guide vanes and moveable wall diffuser (Carrier) refrigeration system adiabatic compression efficiency compressor compressor (pressure ratio) 80% Reciprocating positive displacement compressor rotational speed(rpm) Centrifugal compressor (Rotating impeller) scroll ႔ screw centrifugal tip speed dynamic compression (flowing fluid) angular momentum 15-3
႔ (exchange Centrifugal pump impeller ႔ ႔ centrifugal compressor Refrigerant impeller (axial direction) (radial ) velocity Refrigerant ၏ dynamic pressure impeller static pressure Impeller centrifugal compressor ႔ impeller stage compressor single stage compressor centrifugal compressor Multi stage compressor gas impeller ႔ discharge Multi stage centrifugal Liquid line (intermediate pressures) stage flash gas energy efficiency Reciprocating compressor hermetic ႔ centrifugal compressor open Open centrifugal compressor casing compressor ၏ (winding) multi impeller ႔ suction gas economizer ႔ refrigerant Compressor casing ႔ seal compressor ႔ semi hermetic Hermetic centrifugal housing ၌ ႔ discharge pressure (pressure) impeller ၏ tip velocity impeller (diameter) Compression stage impeller (diameter) impeller (diameter) gear drive impeller multiple stage impeller Gear drive ႔ multiple stage (high speed) impeller Direct drive machine (moving part) bearing Industrial refrigeration multistage centrifugal compressor Centrifugal chiller volume) (variable (constant head) Table 15-1 centrifugal compressor reciprocating screw compressor ႔ Classification Centrifugal Aerodynamic Screw Positive Displacement Reciprocating Positive Displacement Comp. Head Volume Flow Motion Capacity Control Constant Variable High Rotating Continuously Variable Variable Medium Rotating Continuously Variable Constant Low Reciprocating Step Control Centrifugal chiller centrifugal compressor condenser throttling device piping connection control ႔ evaporator ႔ liquid cooler centrifugal chiller 15-4
႔ Chapter-15 Centrifugal Compressors and Chillers purge unit flashing cooler(economizer) turbo machine ႔ Velocity pressure lift Centrifugal compressor static pressure ႔ total head impeller stage two-stage single- three-stage compressor Single-stage centrifugal compressor Impeller ၏ compression ratio (series) (၄) compression ratio HCFC-123(R123) (၄) single-stage centrifugal compressor evaporating temperature 40 F(4.4 C) compression ratio ၏ condensing temperature 100 F (37.8 C) Two-stage single-stage centrifugal compressor ႔ three-stage centrifugal compressor total head lift refrigeration system ၏ COP ၁၅-၆ Centrifugal chiller ၁၅-၇ Carrier centrifugal chiller Refrigerant ႔(vapor) Impeller ၁၅-၈ Flooded evaporator cut-away inlet vane ႔(vapor) diffuser (compress) Second-stage impeller refrigerant ႔(vapor) ၏ volute first-stage impeller ႔ second-stage impeller ႔ ၌ (compress) ၌ Refrigerant velocity pressure Evaporating pressure condensing pressure static pressure ႔ ႔ compressor Second-stage impeller ၏ vapor ၏ acoustic velocity hot gas discharge velocity saturated (atmospheric pressure 15-5
႔ 80 F (26.7 C) HCFC-123 ၏ acoustic velocity HCFC-22 ၏ acoustic velocity Centrifugal compressor to 50,000 rpm) kW) ၌ peripheral velocity Centrifugal chiller rotating speed (from 1800 ၏ refrigeration capacity 10,000 tons(35,000 kW) 100 tons (350 centrifugal chiller Centrifugal chiller turbo machine positive displacement chiller Centrifugal chiller (design c isentropic efficiency 0.83 Centrifugal chiller Centrifugal chiller capacity control ႔ (operating) Part-load ၏ volumetric efficiency 0.6 ႔ 1.0 inlet guide vane (stepless) Inlet vane Inlet Guide Vane(IGV) D centrifugal chiller (engine drive) centrifugal chiller (speed) electric chiller speed centrifugal chiller Variable Speed Drive(VSD) Inlet Guide Vane(IGV) Evergreen chiller components 1. VFD or starter 2. Semi-hermetic motor 3. Compressor 4. Refrigerant distribution 5. Oil pump/lubrication system 6. Condenser 7. Cooler 8. Refrigerant transfer compressor 9. Inlet guide vanes 10. Relief valves ၁၅-၉ 19XR Evergreen Carrier centrifugal chiller ၁၅-၁၀ Carrier 19XR centrifugal hermetic compressor 15-6
႔ Chapter-15 Centrifugal Compressors and Chillers ၁၅-၁၁ Two-stage centrifugal compressor Refrigeration capacity 1200 tons (4220 kW) centrifugal chiller compressor centrifugal chiller hermetic open type compressor ၁၅-၁၂ ( ) Three stage refrigerant flow ၁၅-၁၃ ( ) Three stage P-H diagram Centrifugal chiller ၁၅-၁၂ ( ) Two stage refrigerant flow ၁၅-၁၃ ( ) Two stage refrigerant flow P-H diagram head lift ႇ Direct-drive compressor impeller 15-7
႔ velocity compressor peripheral impeller diameter (energy loss) D Compressor ၏ 2% - 3% Centrifugal compressor central air conditioning system ၏ water-cooled centrifugal chiller Three Stage Centrifugal Chiller ၁၅-၁၃( ) Three stage compressor ၁၅-၁၃(ဃ) Three stage refrigerant flow ၁၅.၂.၁ Centrifugal Compressor Theory Centrifugal compressor aerodynamic Centrifugal compressor turbine scroll reciprocating screw compressor Gas energy ႔ ႔ positive displacement ႔ kinetic energy Centrifugal compressor pressure ၏ lift characteristics (flow rate) Centrifugal compressor ႔ ၏ ႔ ႔ angular momentum ) Compressor Lift temperature Tip speed rotational speed (rpm) lift compressor (length of the ႔ angular momentum tip speed ၌ (common) Table 15-2 refrigerant ၏ chilled water temperature condenser water temperature ႔ Chiller 4% ႔ (molecular weight) string) (wheel diameter centrifugal ႔ ႔ impeller Tip speed approach lift Tip speed 650 fps impeller 15-8
႔ Chapter-15 Centrifugal Compressors and Chillers Chiller cooling refrigerant compressor (cfm) capacity chiller compressor cooling refrigerant Table 15-2 refrigerant properties Refrigerant HCFC 123 HFC 134a HCFC 22 6.10 124.1 195.9 Condenser pressure - psig @ 100 F Evaporator pressure - psig @ 40 F (Inches of Mercury) (18.1) 35.0 68.5 Vacuum) Net refrigerant effect -BTU/lb 66.0 68.0 73 Refrigerant circulated- lbs/min./ton 3.08 3.00 2.78 Gas flow - cfm/ton 18.15 3.17 1.83 Head - BTU/lb 7.73 8.34 9.0 Tip Speed- ft./sec. 656 682 707 Ozone Depletion Potential - ODP 0.02 0.00 0.05 Table 15-3 refrigerant 1 RT 3 cfm ၏ HCFC-123 HFC-134a ၏ Centrifugal compressor impeller inlet velocity HFC-134a 1 RT 17 cfm (density) ၏ design parameter Mach 1 refrigerant gas ၏ Mach number 0.9 1000 ton chiller refrigerant ႔ ႔၏ design parameter Table 15-3 compressor design parameters Refrigerant HFC 134a HCFC 22 HCFC 123 Chiller size (tons) 1000 1000 1000 Compressor Gas Flow Rate (cfm/ton) 2.68 1.74 Compressor Gas Flow Rate (cfm) 2680 1,740 17,080 Tip Speed (fps) 653 678 629 Wheel Speed (rpm) 11,884 19,464 3550 @60hz Wheel diameter (in) 12.6 8 Acoustic Velocity @ 50 F (fps) 484 535 Minimum. Inlet Diameter. (in) 4.6 3.5 HCFC-123 coupled) 17.08 40.6 417 13.0 centrifugal compressor Compressor speed gearbox 3550 (directDirect-drive ၏ Variable Frequency Drive(VFD) speed tip tip speed wheel diameter ၄၀.၆(40.6 inches) HFC-134a ႔ HCFC-22 (gear box) 30,000 rpm centrifugal compressor ႔ compressor (5 inch diameter wheels) Impeller (stress) tip speed 15-9
႔ (square) Rpm wheel stress stress wheel ႔ HCFC-123 wheel diameter diameter two stage (၁၅-၁၂) ႔ two-stage compressor Compressor efficiency ၁၃) Wheel three stage compressor ၏ (cut away) refrigerant economizer economizer two-stage compressor (၁၅- ၏ P-H diagram ၁၅.၂.၂ Centrifugal Chiller Centrifugal chiller ၏ (main components) (၁) Single-stage ႔ multistage (၂) Air-cooled water-cooled (၃) Open semi-hermetic (၄) Direct-drive configuration ႔ ႔ double-bundle condenser ႔ hermetic gear-drive (၅) Inlet guide vane ႔ variable-speed drive capacity control centrifugal compressor centrifugal peripheral velocity machine Refrigeration capacity 100RT 10,000RT (315kW 31,560 kW) ၁၅.၃ System Components ၁၅.၃.၁ Evaporator Flooded shell-and-tube evaporator ႔ (compact size) - centrifugal chiller ၁၅.၃.၂ Condenser Condensing pressure and-tube type condenser capacity control ႔ horizontal shell- centrifugal chiller air-cooled centrifugal chiller ၁၅.၃.၃ Vessel Pass Arrangements Pass tube tube water side heat transfer Temperature Difference(LMTD) water velocity Velocity Velocity Chiller efficiency Log Mean Fluid ၏ (pressure drop) 15-10
႔ Chapter-15 Centrifugal Compressors and Chillers Laminar flow Reynolds number 7500 Reynolds number Reynolds number 7500 fluid velocity velocity tube 3 fps Fluid tube ၌ Tube fps fluid velocity 3 12 fps ၁၅-၁၄ Pass arrangement ၁၅.၃.၄ Flash Cooler Flash cooler economizer liquid refrigerant refrigerant Refrigeration effect saturated condition flash intermediate pressure refrigeration effect single-stage flash cooler Two-stage compressor Three-stage compressor flash cooler two-stage (၁၅-၁၂) ၁၅.၃.၅ Orifice Plates or Float Valves Centrifugal chiller ႔ float valve refrigerant control throttling device (multiple) orifice orifice plates (arranged in series) (၁၅-၁၅) throttling device Condenser liquid refrigerant ၏ liquid cooler ႔ ၌ refrigerant control Full-lo orifice plate Liquid refrigerant orifice plate (pressure drop) Orifice plate orifice plate flow liquid ၏ saturated pressure refrigerant flow control (၁၅-၁၆) Refrigeration load refrigerant variable orifice evaporator Condensing pressure ၌ refrigerant hydrostatic head ႔ fluid pressure Liquid centrifugal chiller condensing pressure centrifugal chiller ၏ condenser ၌ liquid pressure vapor rate) (moving part) Orifice plate liquid refrigerant ၏ saturated pressure second orifice plate Orifice plate condenser f ႔ refrigerant ၏ (flow throttling device (reliable) 15-11
႔ ၁၅.၃.၆ Variable Orifice Variable orifice performance Liquid variable modulating valve control Refrigerant condenser sensor ၌ optimum liquid level ၁၅-၁၅ Orifice plates ၁၅-၁၆ YK centrifugal chiller compressor variable orifice ၁၅.၃.၇ Purge Unit Refrigeration system non condensable gas purge unit ႔(moisture) ႔(moisture) (harmful acids) condenser (moisture) Non condensable gas refrigerant ႔ ၌ ႔ (power consumption) (air) Non condensable gas condensing temp System efficiency consumption) (power (purge) Purge unit (၁) Refrigerant pressure (atmospheric pressure) refrigerant refrigeration system low pressure purge unit (၂) Suction pressure (atmospheric pressure) refrigeration system purge unit (၃) Refrigeration system evacuate ႔ purging ႔ Refrigeration system optimum efficiency purge unit Purge unit Purge Unit (Connecting Point) Air cooled condenser ႔ evaporative condenser system – purge connection receiver purge connection ၏ liquid (top) air cooled (top) ႔ Water cooled condenser system ၌ receiver Receiver evaporative condenser purge connection 15-12
႔ Chapter-15 Centrifugal Compressors and Chillers water cooled condenser ၏ receiver (top) Receiver purge connection liquid inlet ၁၅-၁၇ Centrifugal chiller purge unit (evaporating temperature) 40 F(4.4 C)၌ HCFC-123 ၏ saturated pressure psia(40 kPa abs) dioxide (atmospheric pressure) non condensable gas evaporator non condensable gas condenser ၏ evaporator (flow) ႔၏ condenser 60% refrigerant refrigerant compressor ၏ ႔ purge condensable gas purge unit Purge unit filter dryer refrigerant ၏ ႔ Vacuum pump non condensable gas ႔(moisture) DX coil purge tank Purge tank Condensing unit Condenser ၏ Non purge vacuum pump tank (low-temperature ၌ non (power consumption) purge unit chiller ၁၉၉၅ ႔ (upper part) Condenser condensable gas condensing unit carbon ႔ Non condensable gas 2.6% 5.8 (air) DX coil purge Filter dryer (dirt) (upper part) - non condensable gas ၌ purge tank ႔ 15-13
႔ DX coil refrigerant ႔ ႔ ႔ Refrigerant ႔(moisture) Non condensable gas tank refrigerant Non condensable gas (atmosphere) ႔ Chiller Purge ၌ tank ၏ vacuum purge vacuum pump pump purge unit Purge unit ၏ efficiency purge unit purge refrigerant 0.0049 lb ၏ refrigerant 0.1 to 0.75 lb of Efficiency air purge unit refrigerant HCFC chiller HFC chiller (၅) ႔ purge Purge Drum pressure purge (Methods) Manual purge Refrigerant non condensable gas refrigerant Thermal drum refrigerated purge type purge compressor Refrigerant drum purge unit (recovery) Low temperature refrigeration system double double drum purge unit Purge unit Refrigerant non condensable gas refrigerant vapor ႔ thermal drum ႔ system ႔ ႔ Drum ၌ non condensable gas ႔ pressure regulating valve ႔ non condensable gas ႔(moisture) (atmosphere) refrigerant vapor ႔ ၁၅.၄ Water Cooled Centrifugal Chiller (၁၅-၁၂) three-stage hermetic direct-drive compressor ႔ water-cooled centrifugal chiller HCFC-123 chiller vapor refrigerant (၁) Vapor refrigerant (၂) First-stage impeller (၃) (၄) mixture (flow process) Liquid cooler compressor first-stage impeller hot gas second-stage impeller Second-stage impeller hot gas ၌ inlet vane flash cooler flashed vapor ႔ - ႔ high-pressure (first-stage) flash cooler flashed vapor 15-14
႔ (၅) (၆) Chapter-15 Centrifugal Compressors and Chillers mixture third-stage impeller Third-stage impeller ႔ (discharged) hot gas water-cooled condenser ႔ (၇) Hot gas superheated Condenser ၌ (၈) Liquid refrigerant (၉) Liquid refrigerant cooler saturated ႔ (condense (desuperheated) subcooled ႔ hermetic motor multiple-orifice throttling device ႔ high-pressure flash Refrigerant second-stage impeller hot gas (၁၀) High-pressure flash cooler liquid refrigerant throttling device low-pressure flash cooler first-stage impeller liquid refrigerant evaporator (၁၂) Evaporator ၌ liquid Refrigerant multiple-orifice ႔ refrigerant refrigeration effect ၁၅-၁၈ ( ႔ hot gas (၁၁) Low-pressure flash cooler throttling device multiple-orifice ႔(vapor) ႔ ႔ ) Imperller ( ) Inlet guide vane ၁၅.၅ Performance Rating Conditions Centrifugal chiller ၏ cooling capacity ARHI Standard 550/590-2011 Evaporator (rate) chiller water temperature 100 percent load : 44 F (6.7 C) 0 percent load : 44 F (6.7 C) Chilled water flowrate: : 2.4 gpm/ton (0.43 L/s kW) Table 15-4 Weighting of part- Water-cooled Air-cooled EDB, Condenser EWB, load, percent ECWT, F ( C) F ( C) F ( C) 100 1 85 (29.4) 95 (35.0) 75 (23.9) 75 42 75 (23.9) 80 (26.7) 68.75 (20.4) 50 45 65 (18.3) 65 (18.3) 62.5 (17.0) 25 12 65 (18.3) 55 (12.8) 56.25 (13.5) Percent load 15-15
႔ Condenser water flow rate 3.0 gpm/ton (0.054 L/s per kW) Fouling factor in evaporator: water side 0.0001 h ft2 F/Btu (0.000018 m2 C/W), air side 0 Fouling factor in condenser: water side 0.00025 h ft2 F/Btu (0.000044 m2 C/W), air side 0 Integrated Part Load Value (IPLV) the centrifugal chiller ၏ standard rating condition where A, B, C, D kW/ton or COP at 100, 75, 50, and 25 percent load, respectively. centrifugal chiller ၏ operating condition condition ( standard rating ႔ ) Chilled water leaving temperature water leaving temperature 40 F(4.4 C) 1 F(0.56 C) cooling capacity 50 F(10 C) chilled ႇ 1 F 1.5 percent ( ) Entering condenser water temperature 80 F(26.7 C) entering condenser water temperature 1 F 90 F(32.2 C) ႇ 0.6 percent 1 F cooling capacity 1.0 percent ( ) H cooling capacity 150tons(527kW) 2000tons(7032kW) water-cooled centrifugal chiller Cooling capacity 150tons(527kW) 10,000 tons(35,160 kW) open water-cooled centrifugal chiller (ဃ) Hermetic compressor (motor cooling system) Open compressor bearing seal ႔ liquid refrigerant 2% refrigerant 4% ႔ ႔ Chiller AHRI ၏ average part-load efficiency average part-load efficiency ႔ Chiller IPLV AHRI Standard 550/590-2011 ႔ ႔ multi chiller operation multi chiller operation single-chiller operation 15-16
႔ Chapter-15 Centrifugal Compressors and Chillers ၁၅-၁၉( ) Compressor map of a single-stage centrifugal compressor: (a) constant speed, inlet vane modulation; ၁၅.၆ Centrifugal Compressor Performance Map Centrifugal compressor ၏ performance compressor performance map “compressor map” fan curve Compressor map power input efficiency surge region Volume flow system head volume flow inlet guide vane opening ႔ curve Compressor curve Centrifugal fan specific work ႔ ႔ “compressor performance curve” Centrifugal compressor ၁၅.၆.၁ Centrifugal Compressor Map at Variable Speed Variable Speed Drive map single-stage centrifugal compressor ၏ compressor (၁၅-၁၉- ) (၁) Variable speed chiller (rotating speed) chiller (၂) Head compressor curve ၏ performance curver inlet vane opening(%) ႔ 105% 100% 80% Constant speed performance curve lift (region) ( ) 15-17
႔ ၁၅-၁၉( ) Compressor map of a single-stage centrifugal compressor: (b) variable speed 1 - Vr f (Q) 2 - Vt f (D, RPM) 3 - V Resultant 4 - RPM 5-D 6–Q ၁၅-၂၀ Radial velocity component (Vr) Tangential velocity component (Vt) 15-18
႔ Chapter-15 Centrifugal Compressors and Chillers ၁၅-၂၁ Impeller ၁၅-၂၂ Impeller assembly ၁၅.၆.၁ Velocity Components Compressor gas ၏ velocity velocity component(Vt) radial velocity component (Vr) tangential velocity component (၁) Radial velocity component (Vr) Radial velocity component (Vr) velocity component (Vr) refrigerant gas flow (Q) refrigerant gas Radial (flow) (၂) Tangential velocity component (Vt) Tangential velocity component (Vt) (rotational speed –rpm) impeller ႔ (diameter D) Centrifugal chiller ၏ lift component (Vt) tangential velocity Tangential velocity component (Vt) centrifugal chiller ၏ Radial velocity component (Vr) resultant vector (V) tangential velocity component (Vt) Resultant vector (V) tip speed ႔ impeller tip ႔ Resultant vector (V) volute static pressure ႔ compressor cooling load Vt Chiller unloading pressure diff kinetic energy Vr evaporator Inlet guide vane cooling load ႔ condenser “ G ” Vr ၁၅.၇ Surge of Centrifugal Compressors Centrifugal compressor ၏ “ ” Volumetric flow “surge” head flow Centrifugal compressor ႔ compressor (noise) surge ၌ part load S ၌ refrigerant (vibration) (heat) surge Surge Refrigerant Surge electrical current (flow) electrical current “ ” machine 15-19
႔ gurgles ႔ compressor Incipient Surge electrical current centrifugal compressor ႔ centrifugal fan discharge pressure ႔ Compressor ၏ curve (pressure) ၁၅-၂၃ Centrifugal compressor head (lift) pressure flow characteristics flow ၁၅-၂၄ Impeller drive assembly ၁၅-၂၅ Compressor surge ၁၅-၂၆ Centrifugal compressor head (lift) ၁၅-၂၇ “ ” 15-20
႔ Chapter-15 Centrifugal Compressors and Chillers Suction pressure discharge pressure lift Head (difference) “head” Head refrigerant ၏ aerodynamic Pressure lift (၁၅-၂၅) curve variable-speed centrifugal compressor surge ၌ zero slope compressor speed(n) versus refrigeration load (Qref pressure lift volume flow minimum speed surge 1 - Load Line 2 - Surge Line 3-A 4-B 5 - 40% 6 - 90 Vanes 7 - 100% 8 - Compressor Head 9 - Refrigerant Gas Flow ၁၅-၂၈ Typical single-stage compressor performance curve ၁၅.၇.၁ Two-Stage Compressors Surge Less and Later head compressor ၏ two-stage compressor ၏ (diameter) Single stage compressor compressor (diameter) Component Vt two-stage compressor stage Vr unloading capability single stage ႔ two-stage compressor two-stage single stage compressor Load surge Single-stage compressor ႔၏ (intersection point B) surge (intersection point B) Two-stage compressor 1 - Load line 2 - Surge line 3–A;4-B 5 - 20% 6 - 90 7 - 80 8 - 70 anes 9 - 100% 10 - Compressor head ၁၅-၂၉ Typical two-stage compressor performance curve 11 - Refrigerant gas glow 15-21
႔ Three-stage centrifugal compressor ၌ ႔ (surging region) single-stage centrifugal compressor Inlet guide vane ႔၏ variable-speed compressor control ႔ single-stage centrifugal compressor ၏ - (surging region) stage (surging region) control (surging region) two-stage inlet guide vane single-stage centrifugal compressor single-stage centrifugal compressor three-stage centrifugal compressor compressor ၏ compressor Two- (components) Centrifugal (surging region) ၁၅.၇.၂ Prevention of Surge load entering condenser water temperature System (၁) (high discharge pressure) (၂) (low suction pressure) (၃) ( ’ ) (၄) (high suction temperature) (၅) (Hot gas valve will not work) (၆) Low suction trap (၇) (bearing damage because of thrust) ႔ ၁၅.၇.၃ Rotating stall and Surge of Centrifugal Chillers Rotating stall aerodynamic disturbance (load flow (flow) ) (temperature lift he he ) R ၌ ႔ impeller (reverse flow S ႔ diffuser condenser evaporator pressure gauge Surge condenser refrigerant refrigerant (reverse flow compressor (reverse flow ႔ E ႔ condenser pressure Head pressure refrigerant condenser pressure ႔ evaporator evaporator pressure (reverse flow) Rotating stall (၁) Impeller stall (၂) Vane-diffuser stall (၃) Vane less-diffuser stall ႔ 15-22
႔ Chapter-15 Centrifugal Compressors and Chillers centrifugal chiller ( stall ႔ surge ) Flow ( ) The head temperature ( ) Compressor geometry (ဃ) Position of PRV ( ) Impeller tip speed ၁၅.၇.၄ Impeller and Vane Diffuser Stall Operating point (flow s Flow head) ႔ surge point impeller stalls head vane diffuser s ၁၅.၇.၅ Vane Less Diffuser Stall (surge point) vane less-diffuser stall centrifugal chiller - ( ) Head ႔ stall ( ) lift ႔ lift stall Surge tips Load entering condenser water temperature compressor ႔ (power consumption) ၁၅.၇.၆ Compressor Surge and Stall (၁၅-၃၀) (left) compressor ၏ curve Fan curve compressor ၏ unstable ႔ Operation point refrigerant (left) cooling effect Shaft (work) (heat) compressor Compressor ႔ surge refrigerant ႔ ႔ ၌ ႔ ႔ ႔ compressor shaft ၏ thrust stall bearing ႔ (reverses loads) Load lift surge condenser water supply temperature ႔ temperature lift Centrifugal chiller impeller chilled water supply temperature part load refrigerant gas Full capacity (gap) rate) ႔ Chiller capacity Refrigerant refrigerant (၁၅-၃၁) impeller impeller volute refrigerant (flow tip speed discharge 15-23
႔ moveable discharge geometry refrigerant (flow rate) Moveable diffuser discharge ၁၅-၃၀ Typical compressor performance curves ၁၅-၃၁ Typical centrifugal compressor performance with various pre-rotation vane settings Centrifugal compressor ၏ (flow) (unstable ႔ (၁) Condenser (၂) Condenser coolant flow (၃) Condenser ၌ non condensable gas 15-24
႔ Chapter-15 Centrifugal Compressors and Chillers ၁၅-၃၂ Compressor movable diffuser geometry ၁၅.၈ Capacity Control of Centrifugal Chillers Centrifugal compressor Vane(IGV) ႔ ၏ capacity control Pre-Rotation Vanes (PRV) Impeller adjustable vane refrigerant impeller ၏ inlet guide vane refrigerant ႔ differential (lift) Low-pressure side (evaporator) Lift evaporator ႔ pressure impeller ၏ speed Lift condenser Lift impeller Impeller capacity inlet guide vanes impeller ႔ Variable inlet guide vanes centrifugal compressor energy efficient water temperature reset part-load performance inlet guide vane control (flow rate) Refrigerant centrifugal compressor (flow rate refrigerant inlet vane (speed) Danfoss impeller Impeller ၏ high-pressure side (condenser) VSD Inlet Guide centrifugal compressor Turborcor compressor magnetic bearing variable (magnetic field) Bearing (frictionless compressor ၏ efficiency (maintenance) heat transfer efficiency Hot Gas ByP compressor hot gas compressor suction ႔ ႔ ႔ 15-25
႔ Hot Gas By part-load (energy saving) turndown ႔ Head control suction damper Suction valve artificial head ႔ suction valve Artificial head suction valve head Head Refrigeration suction valve control Centrifugal compressor refrigerant (volume flow) modulating c Centrifugal compressor ႔ ၏ refrigerant gas flow prerotation vanes adjustable inlet guide vanes actuator Vane impeller Axial shaft Vane ႔ vane ႔ gas (fully open) Inlet vane inlet guide vane axial shaft gas Vane Inlet vane gas impeller impeller impeller “ (flow rate) ႔ ႔ (၉၀) ႔ ႔ inlet vane impeller ၏ ႔ preswirl ” Inlet Centrifugal compressor “ Centrifugal compressor ” refrigerant flow refrigerant flow operation (minimum volumetric rate flow) (stable) Compressor volumetric flow rate 40% hot gas bypass envelope 60% Surge Capacity control speed control Variable frequency drive control capacity vane (motor speed) Variable frequency drive speed control efficiency Compressor speed capacity refrigerant ႔ Part-load operation Refrigerant pressure (lift) centrifugal compressor compressor ၏ ၏ capacity control (၁) Inlet guide vane (၂) Compressor (၃) Inlet guide vane (speed) variable speed drive (၄) variable speed control (gas-turbine-driven) (steam) ႔ centrifugal chiller ႔ (speed) 15-26
႔ Chapter-15 Centrifugal Compressors and Chillers Hot-gas bypass (energy saving) comfort cooling system Centrifugal compressor Part-load operation centrifugal fan inlet vane Centrifugal chiller ႔ centrifugal turbo machinery variable-speed drive refrigerant effect pressure ႔ evaporating pressure lift Refrigerant flow ၏ friction (pressure drop) Part-load operation system head system head ၏ refrigerant volume flow Part-load operation condensing pressure Condensing pressure condensing system head evaporating pressure entering condenser water temperature condenser Water-cooled entering condenser water temperature (outdoor wet- bulb temperature) ၁၅.၈.၁ Required System Head at Part-Load Operation Part-load operation refrigerant volume flow condensing evaporating surface area ႔ condensing temperature evaporating temperature cooling load (outdoor wet-bulb temperature) ၁၅.၈.၂ Capacity Control Using Inlet Vanes Inlet vane impeller (၁၅-၁၈) (inlet) inlet guide vane impeller ၏ chiller performance inlet vane pivoted movable vane Three-stage centrifugal chiller inlet vane Inlet guide vane Fluid ၏ absolute velocity vane vapor refrigerant ၏ volume flow tangential component (p (opening angle (inlet)၌ Impeller Vane refrigerant vapor compression efficiency inlet area radial entry (deviate) Load ratio compression efficiency compression efficiency Load ratio Head lift vapor refrigerant shaft power Single-stage centrifugal compressor inlet vane (၁) Entering condenser water temperature 0.12 ႔ operating curve capacity control load ratio surge line 15-27
႔ (၂) Load ratio 0.1 0.5 condenser water temperature 2.5 F compression efficiency ၁၅-၃၂( Load ratio 50 percent ) Performance map of a fixed-speed centrifugal compressor with variable inlet guide I ’ capacity control ၁၅.၈.၃ Inlet Guide Vane (Pre-Rotation Vane) Inlet Guide Vane(IGV) Pre-Rotation Vane (PRV) motor Constant speed Partial load operation Inlet guide vane impeller ၏ (saving energy) (suction inlet) panel Inlet guide vane control (automatic control Inlet Guide Vane(IGV)၏ (၁) Inlet Guide Vane(IGV)၏ ႔ refrigerant gas impeller wheel (၂) Partial load operation inlet guide vane Impeller suction gas ၏ (velocity) specific volume (၃) Centrifugal impeller ၏ (၄) Inlet guide vane ၏ ႔ refrigerant gas ၏ (pressure) centrifugal chiller ၏ capacity (angle) performance cooling load operating condition inlet guide vane compressor Centrifugal compressor ၏ turn down ratio “ ” Inlet guide vane surge capacity 10% compressor ၏ performance curve Mach number variable speed control hot gas bypass ႔ 15-28
႔ Chapter-15 Centrifugal Compressors and Chillers ၁၅-၃၂( ) Performance map of a variable-speed, variable-IGV compressor with IGV/speed combinations for optimum efficiency. ၁၅.၈.၄ Capacity Control by Variable Speed Centrifugal chiller variable speed drive rotating speed (rotating speed volume flow (၁) Load ratio 0.5 variable speed control ႔ design operating curve load ratio surge line Centrifugal compressor curve (speed) (speed) ႔ compressor compressor (speed) curve compressor c
Centrifugal compressor ၌ peripheral velocity rotating speed (from 1800 to 50,000 rpm) Centrifugal chiller ၏ refrigeration capacity 100 tons (350 kW) 10,000 tons(35,000 kW) centrifugal chiller Centrifugal chiller turbo machine positive .
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Part One: Heir of Ash Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18 Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26 Chapter 27 Chapter 28 Chapter 29 Chapter 30 .
Paper 1. Assessment of the 3D Flow in a Centrifugal compressor using Steady-State and Unsteady Flow Solvers 91 Paper 2. Generation Mechanisms of Rotating Stall and Surge in Centrifugal Compressors 117 Paper 3. Centrifugal Compressor: The Sound of Surge 137 Paper 4. Acoustic signature of flow instabilities in radial compressors 163 Paper 5.
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TO KILL A MOCKINGBIRD. Contents Dedication Epigraph Part One Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Part Two Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18. Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26
sibilities include centrifugal and reciprocat ing compressors, axial flow compressors, steam and gas turbines, centrifugal and reciprocating pumps, and gas expanders. He has been employed at Parsons for the last 20years and previously at Worthington Compressor and Engine International as an Appli cation Engineer in power and process marketing.
Elastomeric bumpers (ASME A17.1 year 2013 & prior) or buffer springs (ASME A17.1 year 2016) Platform Sizes 48"W x 54"D standard 42"W x 60"D optional 42"W x 54"D standard 51"W x 51"D 90 optional Specifications Power supply: 208/230 VAC, 1 ph, 30 amp, 60 hz Capacity: 1400 lb. (635 kg) Speed: 30 fpm (.15 m/s) Travel: up to 25'0" standard Three-year .
