CO2 Bitzer

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Mostra Convegno Expocomfort, XVI EU Conference on "The Refrigerant Revolution , a 79% reduction" - Milan 20th March 2014

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CO2 Bitzer

  1. 1. BITZER CORE COMPETENCE – RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS BITZER Kühlmaschinenbau GmbH 2014, Rottenburg-Ergenzingen
  2. 2. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 2 TABLE OF CONTENTS 1. Preface 2. BITZER CO2 Compressors for sub-critical applications / Product range / What is new? / Why BITZER? 3. BITZER CO2 Compressors for trans-critical applications / Product range / What is new? / Why BITZER? 4. Documentation and Software 5. Outlook and Conclusions
  3. 3. Preface
  4. 4. CO2 – A Special Refrigerant with Unique Properties and Specific Requirements Pro‘s  Long tradition in refrigeration  Low Global Warming Potential (GWP =1)  Chemically inactive, non-flammable  Not toxic in the classical sense  Very high volumetric refrigerating capacity  Subcritical: 6 to 8 times higher than for R22, R404A or NH3  Transcritical: 4 to 5 times higher than for R22, R404A  Low refrigerant mass flow  … and it’s in beer  so it must be good The ideal refrigerant???
  5. 5. CO2 – A Special Refrigerant with Unique Properties and Specific Requirements Con‘s  Critical temperature at 31°C ● requires trans-critical operation for single stage and compounded 2-stage applications (HP up to 150 bar) ● unfavourable thermodynamic properties for systems with higher discharge pressures / gas cooler outlet temperatures  Extremely high discharge pressures ● safety aspects (regulations) and component design  Limited low temperature range (triple point -56.6°C)  Lower practical limit in air than with HFCs (3.5 to 6 times less) ● CO2 is odourless − for closed rooms this may require special safety and detection systems
  6. 6. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 6 COMPRESSORS FOR CO2 APPLICATIONS IS IT A SUCCESS? “Actually, it’s not too bad!” / Compressors for sub-critical applications: more than 15 years of experience! / First trans-critical field test in a Swiss hypermarket was commissioned in Nov. 2004 / More than 25000 BITZER CO2 compressors in the field / More than 40 project partners for commercial applications / No. of trans-critical systems in EU > 2880 (list of suppliers not even complete) http://guide.shecco.com/guide.php / Other applications: Heat pump, AC, Industrial Refrigeration and Railway
  7. 7. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 7 COMPRESSORS FOR CO2 APPLICATIONS IS IT A SUCCESS? Reference: http://guide.shecco.com/GUIDE-Natural-Refrigerants-Europe-2014.php
  8. 8. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 8 COMPRESSORS FOR CO2 APPLICATIONS IS IT A SUCCESS? Reference: http://guide.shecco.com/GUIDE-Natural-Refrigerants-Europe-2014.php
  9. 9. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 9 COMPRESSORS FOR CO2 APPLICATIONS IMPRESSIONS SMA References (alphabetic order): Advansor, Carnot, Carrier, Fischer, Heifo, Jessen Jürgensen, Teko, Veld
  10. 10. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 10 COMPRESSORS FOR CO2 APPLICATIONS IMPRESSIONS HPWH References: Advansor Reference: Itomic
  11. 11. BITZER CO2 Compressors for Sub-critical Applications
  12. 12. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 12 CO2 COMPRESSORS FOR SUB-CRITICAL APPLICATIONS – SL COMPRESSOR RANGE Based on: SCT -35 °C / Toh 20 K / SDT -5 °C / 50 Hz
  13. 13. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 13 CO2 COMPRESSORS FOR SUB-CRITICAL APPLICATIONS – MAXIMUM OPERATING PRESSURE MOP of 53 bar on HP side introduced with serial no. 16765005988
  14. 14. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 14 CO2 COMPRESSORS FOR SUB-CRITICAL APPLICATIONS – APPLICATION RANGES ° °
  15. 15. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 15 Multi cylinder design and optimized bore/stroke ratio – Low vibration & sound – Best suited for VSD Highly efficient and robust working valves – Large cross sections – Improved compression process Extra low oil carry-over – Special centrifugal lubrication Further developed wear resistant drive gear / special bearings WHY BITZER? ADVANCED COMPRESSOR DESIGN! EXCELLENCE IN PERFORMANCE Special motor adaptation: tc up to 15 °C Housing with high strength pressure: HP: up to 53 bar LP: up to 30 bar Specially designed cylinder heads
  16. 16. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 16 Test conditions Short cycling with high liquid fraction in suction gas Target: No visual wear after testLT (sub-critical) Additional tests at extreme thermal and pressure loads WHY BITZER? QUALIFICATION PROGRAM (SMA)
  17. 17. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 17 VARIABLE SPEED DRIVE (VSD) / Capacity adaptation by use of variable speed drive  Standard speed range (HC: 30…60 Hz; SL: 30...70 Hz)  Trans-synchronous operation: motor reserve limited with R744 (constant torque requirement)  For a constant torque above 50 Hz  VSD with auxiliary transformer (higher output voltage)  Motor layout 230 V / 3 / 50 Hz 40 Hz 30 50 60 70
  18. 18. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 18 Recips: Torque characteristic is not homogeneous!  Breaking torque to start the rotation (heavy duty conditions) / 2-cylinder faktor F2 = 2.0 / 4-cylinder factor F4 = 1.6 / 6-cylinder factor F6 = 1.4 I max. 60 s Freq.Inv. = I max. comp. x F 2…6 x √3* * Motor connection: 400 V /Star motor in 230 V / Delta? VARIABLE SPEED DRIVE (VSD)
  19. 19. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 19 APPLICATION RANGE WITH VSD Lower frequencies cause: lower effect of the suction gas cooling, torque demand becomes more asymmetric, lower efficiency of the motor, harmonic content increases, rising motor temperatures
  20. 20. BITZER CO2 Compressors for Trans-critical Applications
  21. 21. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 21 CO2 COMPRESORS FOR TRANS-CRITICAL APPLICATIONS
  22. 22. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 22 CO2 COMPRESORS FOR TRANS-CRITICAL APPLICATIONS
  23. 23. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 23 TECHNICAL DATA Maximum Operating Pressures 53 42 30 25 / Previous design  MOP on LP side: 75 bar  MOP on HP side: 130 bar / Current design, starting from serial no. 1680518739  MOP on LP side: 100 bar  MOP on HP side: 160 bar  Both values valid for stand still operation
  24. 24. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 24 NEW DESIGN FOR CKH4 MODELS
  25. 25. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 25 PROCESS OF CONTINOUS IMPROVEMENTS Number and positioning of Schrader-vales and plugs has been changed Enforced bearing cover, coated steel gaskets, round hole pattern Enforced cylinder heads, coated steel gaskets Enforced bearing cover, coated steel gaskets, round hole pattern NO changes in footprint and valve positions, new assemblies not interchangeable, starting with serial no. 1684413588
  26. 26. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 26 DIMENSIONAL DRAWINGS
  27. 27. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 27 APPLICATION LIMITS
  28. 28. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 28 Standard extent of delivery / Blind flanges on HP and LP side / Relief valve on HP side / Crankcase heater included / Rubber elements / Option: Discharge shut-off valve, Swagelok © / Option: Discharge shut-off valve for brazing / Option: Discharge shut-off valve for welding / Option: Suction shut-off valve for brazing / Option: Relief valve on LP side EXTENT OF DELIVERY
  29. 29. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 29 CHALLENGES WITH CO2 Influences on the Reliability High suction densities Strong degassing effects Boundary friction Wear on drive gear Resulting gas forces High pressures & pressure difference
  30. 30. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 30 Undersquare stroke- bore ratios All bearing seats feature large surfaces Multi-layer bearings Specially treated piston surfaces, low average piston velocities, low pressure reduction per piston ring Enforced connecting rods incl. bearings Piston pin largely dimensioned & large seating WHY BITZER? ADVANCED COMPRESSOR DESIGN! MEASURES FOR HIGH RELIABILITY
  31. 31. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 31 Test conditions 9000 starts, 2 min go / 4 sec stop Liquid fraction in suction gas ≥ 25% Target: No visual wear after test Discharge temperature down to 20°C WHY BITZER? QUALIFICATION PROGRAM 1350 h @ 25 Hz 1350 h @ 87 Hz Regular cycle & liquid suction continuous 1300 h / 1150 cycles
  32. 32. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 32 4-cylinder design, optimized stroke-bore ratio – 3 piston rings – low dead volume – optimized flow cross sections – low discharge pulsation Special adaptation of motor layout and suction gas cooling – 4-pole design for VSD up to 87 Hz – no extra oil cooling Highly efficient and robust working valves – large cross sections – optimized shape and position Extra low oil carry-over – special centrifugal lubrication WHY BITZER? ADVANCED COMPRESSOR DESIGN! EFFICIENCY Housing with high pressure strength : HP up to 160 bar LP up to 100 bar Separated HP/LP chambers – reduced heat transfer – no external piping
  33. 33. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 33 p = 1.8 to = -8 °C tc = 15 °C p = 3.2 to = -8 °C p_HP = 90 bar, e.g. t_gc_out = 35 °C Isentropic efficiency (terminal) clearly above 0.65 4HTC-20K, Toh = 10 K, 50 Hz WHY BITZER? ADVANCED COMPRESSOR DESIGN! EFFICIENCY
  34. 34. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 34 THE APPLICATION OF VSD / Capacity adaptation by use of integrated or external inverter  Standard speed range (30 Hz…70 Hz)  Trans-synchronous operation: motor reserve limited with R744  Measures for constant torque above 50 Hz:  VSD with auxiliary transformer (higher output voltage)  Motor layout 230 V / 3 / 50 Hz (40S, connected in ∆) 40 30 50 60 87 Hz
  35. 35. BITZER CO2 VARISPEED Compressors for Trans-critical Applications
  36. 36. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 36 TRANS-CRITICAL CO2 VARIPSEED COMPRESSORS Product range / Compressor models with direct-mounted frequency inverter:  4PTC-7.F3K  4MTC-10.F4K  4KTC-10.F4K / Frequency range 30 – 87 Hz / Slightly different application limits  Reduced motor cooling at lower frequencies
  37. 37. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 37 TRANS-CRITICAL CO2 VARIPSEED COMPRESSORS Features of the BITZER CO2 VARISPEED compressors / Optimum capacity adaption due to stepless speed control / High system efficiency due to reduced suction pressure fluctuations as well as optimized compressor running time / Integrated maintenance-free suction gas-cooled frequency inverter / Frequency inverter is completely parameterized at delivery state, thus, easy commissioning / No starting current peaks at compressor start / Direct power supply at 400 V / 3Ph / 50 Hz possible / Easy parameterising by means of BEST Software (BITZER ELECTRONICS SOFTWARE TOOL)
  38. 38. Documentation, Software and Services
  39. 39. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 39 BITZER CO2 COMPRESSORS  TECHNICAL DOCUMENTATION Product leaflets KP-120, KP130 and KP132 / Contents: General description, capacity range, application ranges, performance data, technical data, dimensional drawings
  40. 40. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 40 Operating instructions KB-120 and KB-130 / Contents: Safety issues, application ranges, connections, commissioning, measures to prevent inadvertent CO2 emission, etc. BITZER CO2 COMPRESSORS  TECHNICAL DOCUMENTATION
  41. 41. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 41 BITZER SOFTWARE Selection of compressors, condensers and accessories
  42. 42. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 42 Performance data for all CO2 compressors BITZER SOFTWARE
  43. 43. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 43 Simulation of various system configurations BITZER CO2 Calculation Tool
  44. 44. Outlook and Conclusions
  45. 45. BITZER // RECIPROCATING COMPRESSORS FOR SUB- AND TRANS-CRITICAL CO2 APPLICATIONS // Page 45 OUTLOOK AND CONCLUSIONS BITZER provides the most favourable CO2 compressor offering: / Product and application ranges for sub-critical and trans-critical systems / Technical documentation and software / Technical training and special services BITZER CO2 compressors set new standards and show the benchmark / Trendsetting technology / Smooth operating behaviour, low sound & vibration levels / Proven long term reliability / Highest performance and efficiency / ASERCOM certified – the only certified compressors for CO2 applications

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