Reciprocating Compressors Past, Present, and Future

Transcription

1 Reciprocating Compressors Past, Present, and Future How Reciprocating Compressors Uniquely Satisfied The Evolving Need For Compression Of Both Air And Refrigerants John P. (Jack) Elson, Ph.D. Purdue Herrick Laboratory Graduate Retiree - Emerson Climate Technologies

2 Introduction / Overview Reciprocating Compressors Are Arguably The Oldest Mechanical Compressor Technology Reciprocating Air Compressor Development Was Driven By The Need For Pressurized Air By Manufacturing, Mining And Construction Refrigerant Compressors Followed Air Compressors With Semi- Hermetic And Hermetic Designs With Internal (Refrigerant Cooled) Hermetic Motor Drive Beginning in the 1960 s Compressor Technology and Product Development Benefited From Dynamic Instrumentation and Digital Computer Simulations Using Mostly Reciprocating Compressors Reciprocating Compressors Continue to See Broad Application Throughout the Refrigeration and Air Conditioning Industry

3 Early Air Compression History Human Lung Bellows BC Mechanical Piston Compressor 1762 (1 PSIG) (5 PSIG) (15 PSIG)

4 Slider Crank And Piston Origins Hierapolis Sawmill 3 rd Century Eccentric Crank Connecting Rod Reciprocating Motion Waterwheel Drive Otto Von Guericke Designed Single Piston / Cylinder & Experimented With Compressed Air And Vacuum Hierapolis Sawmill Stone Cutting 3 rd Century Asia Minor

5 Mechanical Air Compressor Development Piston Type Blowing (Air) Machine John Smeaton (1762) Designed By John Smeaton To Provide The High Volume Air Flow Needed To Increase The Temperature Of Multiple Metal Melting Furnaces Carron Iron Works (United Kingdom) 4 Cylinder Design With Strokes/Min 1 Every 3 Seconds 15 PSIG With Significant Leakage First Mechanical Air Compressor

6 Improved Efficiency With Cylinder Boring Machine (Product Improvement With Manufacturing Tool) Significant Manufacturing Contribution by John Wilkinson Industrialist / Manufacturing Engineer Invented a Cylinder Boring Machine Using a Translating Cutting Head With Cylinder Rotation to Reduce Leakage and Improve Air Flow Improved Efficiency With Improved Manufacturing Technology - Demonstrated the Importance of Both Manufacturing and Product Design Contributions Cylinder Boring Machine Cylinder For James Watt s Steam Engine

7 Air Compressor Development Benefited From Opportunity And Technology Contributions Factory, Mining, and Construction Applications Drive Air Compressor Need Thomas Cochrane Developed Pneumatic Rock Drills For Mount Cenis Railroad Tunnel in Swiss Alps - Reduced 8.5 Mile Tunnel Completion From 25 Year Estimate to 14 Years Refrigeration Compressor Designs Benefitted From Early Air Compressor Technology Mount Cenis Tunnel Swiss Alps ( )

8 Vapor Compression Cycle - Key To Mechanical Refrigeration Development Professor William Cullen, University of Edinburgh Demonstrated the Concepts of Latent Heat and Saturation Pressure 1 st Demonstration of Artificial Refrigeration 1805 Oliver Evans Described a Closed Refrigeration Cycle to Produce Ice By Using Diethyl Ether Under a Vacuum 1835 Jacob Perkins Designed, Built And Patented Evans System Demonstrated Ice Production Refrigerant Compressors And The Expansion Valve/Orifice Replaced A Hand Pump Operated System Vacuum Pump Positive Pressure Pump Jacob Perkins British Patent I am enabled to use volatile fluids for the purpose of producing the cooling or freezing of fluids, and yet at the same time constantly condensing such volatile fluids, and bringing them again into operation without waste. (Jacob Perkins)

9 Small Refrigeration Condensing Unit Single Piston Design With Rod Crossheads Shaft Seal - Axial Motion Early Electric Motor Drive Required On-Site Electricity

10 Small Commercial Refrigeration Compressor Steam Engine Drive With Duplex Compressors Portable With Available Steam Piston / Rod Replaced Rod Crosshead For Better Internal Lubrication and Lower Cost Shaft Seal Rotating Shaft Design Used For Making Ice And Other Evolving Commercial Refrigeration Applications

11 Early Refrigerator Open Drive Condensing Unit Household Refrigerator Application Required Motorized Belt and Pulley Drive Included Condenser Coil Typical Speed 900 rpm or less Primary development challenges included: Shaft Seal Design for Low Leakage of Oil and Gas Hazardous Refrigerants Open Drive Design 1910

12 1 st Generation (1920 s) Household Refrigerator Design With Remote Condensing Unit External Drive Compressor With Electric Motor Replaced Ice Box Ice Blocks Compressor and Condenser Located in Basement Single Condensing Unit Could Supply Multiple Refrigerators Shaft Seal Leakage Potential With External Drive Toxic refrigerants Sulfur Dioxide & Methyl Chloride High initial cost $600 more than a Model T Ford Kelvinator Design Approach

13 Early Mechanical Household Refrigerators 1914 Alfred Mellows - Design Purchased by William C. Durant to Form Frigidaire Company in Edmund Copeland Started Kelvinator Company Using His Automatic (Thermostatic) Temperature Control 1923 General Electric, Frigidaire and Kelvinator Attained 80% of Household Refrigerator Market General Electric Produced the Monitor Top Refrigerator, the First Self-Contained Refrigeration Unit With Internal Hermetic Motor and Hermetic Seal Freon 12 Identified and Patented by Frigidaire (GM) Allowed Entire Industry to Use Their Refrigerant! 5000 Mechanical Refrigerators Manufactured in 1921 and 1 Million in 1931 With Cost Reduced $600 to $160 Mechanical Refrigerators Became Accepted Replacements For Previous Ice Box Designs Monitor Top GE Design (1928)

14 Reciprocating Compressor Designs Evolved To Meet The Increasing Market Needs For Both Refrigeration And Air Conditioning Open/External Drive For Early Refrigerators And Commercial Refrigeration, Transport Refrigeration and Automotive Air Conditioning Semi-Hermetic With Integral Hermetic Motor And Serviceability For Commercial Refrigeration and A/C Hermetic For Increased Speed and Reduced Cost For Central Air Conditioning and Refrigeration

15 Reciprocating Compressor Product Evolution Timeline Open Drive Refrigerator Hermetic Refrigerator Piston/Rod or Linear Piston Open Drive Transport Refrigeration Open Drive Automotive A/C Piston/Rod or Piston/Swash Plate Initial Refrigeration Compressors Were Open Drive With External Electric Motor Open Drive Commercial Refrigeration Semi - Hermetic Commercial Refrigeration & A/C 4 Pole Hermetic A/C 2 Pole Hermetic A/C, HP, Ref

16 Open Drive Refrigeration Compressors 1930 s Refrigeration Product Generally Sold With a Condensing Unit for Commercial Refrigeration Applications Single and 2 Cylinder Designs Motor Protection Methyl Chloride / Freon 12 Refrigerant Replaced By New Semi-Hermetic Designs For Commercial Refrigeration and A/C

17 Semi - Hermetic (Accessible) Reciprocating Compressors Instrumental in the Production and Market Success of Multiple Size Refrigeration and A/C Systems 1750 rpm 4 Pole Motors Simplified Compressor Packaging With Integral Motor Reliable and Serviceable With Remanufacturing Capability 2,4,6,8 Cylinder Product Line (50 HP Maximum) Early Development Challenges Refrigerant cooled Hermetic Motors / Refrigerant Gas Management Internal Motor Protector /Internal Temperature Sensing Multiple Models and Frame Sizes Valve Design / Analysis for Higher Speed, Higher Efficiency and Low Stress Small 2 Cylinder Semi-Hermetic Compressor

18 4 Pole Hermetic Compressor Welded Shell ( Hz) Launch? Air Conditioning Application 4 Pole Hermetic Motor ~ 1750 RPM 4 Cylinder Design ( HP Models) Positive Displacement Gear (Gerotor) Oil Pump Semi-Hermetic Origin Welded Steel Housing - Deep Drawn Shell Components Internal Suspension & Flexible Discharge Tube Limited Time In Production Due To 2 Pole Hermetic Product Success

19 2 Pole Hermetic Compressor - Efficiency / Noise Design Challenges ( Hz) Launch Air Conditioning And Refrigeration Models Reduced Size and Lower Cost (2-15 HP) 1,2, And 4 Cylinder Designs Major Design Challenge For Both High Efficiency and Low Noise Due to Compact Design and Higher Valve Port Velocity Early Bearing And Reed Valve Issues Resulted From Higher 2 Pole Motor Speed And Liquid Refrigerant Migration To Compressor Oil Sump. Crankcase Heaters and Low Side Accumulators Were Added To Help Resolve The Liquid Migration Problem Compressor Design improvements Ultimately Improved Liquid Tolerance Capability

20 Heat Pump Systems and High Efficiency Requirements Drive Major Hermetic Compressor Improvements Both A/C and Heat Pump Performance Became Very Important During the 1970 s Oil Embargo Accelerated The Need For energy Conservation Electric Resistance Heat Was Very Expensive Hermetic Compressors Redesigned For Both A/C And Heat Pump Performance Lower Bore/Stroke Ratio and Reduced Discharge Port Clearance Volume Were Both Important For the Heat Pump Application With Some A/C Efficiency Difficulty Gas Flow Pressure Losses Reduced To Improve Efficiency Compressor EER (ARI) Gradually Increased From 7-8 In 1970 to 10 in 1990.

21 Compressor Instrumentation, Mathematical Modeling And Computer Simulation Valve Failures And Compressor Performance Improvement Requirements Increased Manufacturer s Interest In Compressor Instrumentation And Computer Simulation Herrick Laboratories And Others Began in The 1960 s to Investigate the Use of Instrumentation to Measure Valve Strain, Valve Motion and Cylinder Pressure Inside an Operating Reciprocating Compressor Mathematical Modeling and Mainframe Digital Computers Were Used to Simulate Internal Compressor Parameters For Comparison With Experimental Measurements. FEA/CFD/FSI Tools Were Not Available At That Time To Simulate Compressor Valve Motion And Stress With High Accuracy, And Digital Computers Had Limited Computation Ability Compared to Current Computers And Software Current Use Of FEA/CFD/FSI Tools And Modern High Speed Computers Is Now Encouraging With Accurate Valve Stress Simulation Appearing To Be Feasible

22 Valve Strain Gage Challenge Tecumseh Products Sponsored the First Herrick Laboratory Project to Measure Valve Strain in a 3500 rpm Compressor Welded Shell Typically Converted to Flanged Bolted Shell Strain Gage Location Was a Best Guess Based on Thin Plate Theory and Bench Test Static Loading Epoxy Was Used to Secure Gages and Wire to the Valve Surface, and Then Brought Through a Gasket Boundary to Minimize Motion and Damage. Wires Exited Compressor Through Valve Plate and Bolted Shell Gaskets Oscilloscope Photos Documented Results Strain Gage Technology Remains an Essential Part of Reciprocating Compressor Valve Development Today Professor Ray Cohen Ring Valve Strain Measurement Wayne Suzuki

23 Early Mathematical Model / Computer Simulation First Herrick Lab Mathematical Model / Computer Simulation Investigation First Vibration Mode Model for Valve Dynamics Effective Flow Area and Force Area Measured by Bench Tests With Air Flow Meter Suction and Discharge Plenum Pressure Assumed Constant No Flow Pulsations Valve Motion And Performance Assessment Instrumentation Cylinder Pressure Measured with Piezoelectric Transducer Induction Probes Used For Valve Motion And Timing Mark For Crank Bottom Dead Center Mainframe Digital Computer Used to Run FORTRAN Program First Mathematical Model / Computer Simulation Project (HL) Dr. Martin Wambsganss 1966

24 Typical Simulation Results for Reciprocating Compressors (1960 s 1970 s) Basic capability to generate P-V diagrams and mass flow through valves to calculate compressor capacity and efficiency Calculated Compressor Performance With Refrigerant selection, operating conditions and speed (RPM) Suction and Discharge Gas Pulsations Were Included to Better Simulate Valve Performance Valve Dynamics Were Typically Limited to a Single Vibration Mode Assumption Reciprocating Compressor Simulation Purdue Compressor Conference MacLaren, Kerr, Tramschek - University of Strathclyde, Glasgow. UK

25 Current Technology Status for Valve Mathematical Modeling and Computer Simulation Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD) and Fluid Structural Interaction (FSI) have Significantly Improved Valve Performance and Stress Prediction Simulation Predicts Higher Frequency Valve Vibration With Inclusion Of Complex Boundary Conditions Due to Valve Backing Plates And Cylinder Deck Stops Includes Complex 3D Fluid Flow And Pressure For Dynamic Valve Loading Digital Twin Technology Is the Future! (Compressor Test For Verification Only) Reduce Or Eliminate Life Testing of Multiple New Model Compressors Intake Valve Valve Velocity Valve Stress Velocity Strain Velocity Contours Velocity Vectors Pressure Contours

26 Compressor Mathematical Modeling and Computer Simulation - PPF Forecast Time Tools FEA Advanced FEA, CFD, FSI Computer Cluster, Cloud, Internet Of Things Overall Performance Prediction (Valves, Flow Loss, Bearings, Motor, Etc. ) Valve & Flow Loss Analysis (Porting, Manifolds, Piping) +/- 5% +/- 2% +/-0.5% Lumped Parameter, 1D Flow, Validation Testing 3D Flow, Reduced Validation Testing Verification Testing Only Flow/Pressure Contours 2D Pen Plotting 3D Animation Flow Path Optimization Valve Vibration and Stress First Mode Analysis High Frequency FEA Valve Stress Prediction Wear Prediction (Valves / Bearings) Component Analysis Contact Pressure And Velocity Data Wear Prediction Product Reliability Assessment Bench Test, Life Testing, Failure Mode Identification FEA, CFD, FSI, Bench Tests With Reduced Life Testing Wear Rate Prediction Reliability Life Prediction Model Degrees of Freedom Technical Maturity Academia, R&D Main Stream Digital Twin Capability Simulation Cost / Benefit High Low Lower Testing Capabilities Performance and Reliability Strain Gage, Induction Probe, Piezoelectric Transducers, and Oscilloscope Digital Image Correlation, Wireless Sensors, A/D Recorders, High Speed Camera, Other? Verification Testing Only Minimal Test Hardware and Test Facility Resources

27 Reciprocating Compressor Future Products Assessment Hermetic Refrigerator Reciprocating Remains The Primary Product With Conventional Piston/Rod or Linear Piston Semi-Hermetic Ongoing Competition With Scroll and Screw Designs With Growth Occurring With CO2 and Other Low GWP Refrigerant Applications Open Drive Transport Primary Products Are Reciprocating and Scroll But With Some Migration To Electric Hermetic Scroll Open Drive Automotive Primary Product is Multi-Cylinder Reciprocating but Electric Cars will likely Use Electric Variable Speed Scroll or Rotary Compressor Hermetic Scroll and Rotary Will Continue To Replace Reciprocating Designs. Primary Reciprocating Market is Mainly High Ambient Locations (MEA)

28 Future Development Opportunities For Reciprocating Compressors New Refrigerants - CO2 Compressors Have Been Developed Using Modified S-H Reciprocating Compressor Designs Advanced Electronic Controls - Protection For Premium S-H Products Low Cost (2 Step?) Modulation For Efficient Hermetic Compressor Capacity Control

29 Reciprocating Compressor Future Reciprocating Compressors Remain a Versatile Refrigerant Compression Technology With Many Successful Product Variations to Meet Ongoing Refrigeration and A/C Market Needs Reciprocating Compressors Have Demonstrated Worldwide Application Success Including Models Using Low Global Warming Refrigerants Such As CO2

30 Acknowledgements Ray W. Herrick, Tecumseh Products - For His Financial Support of The Ray W. Herrick Laboratories at Purdue University Purdue Professors Bill Fontaine and Ray Cohen For Their Contributions to The Success of the Herrick Laboratories and Early Research Projects Concerning Reciprocating Compressors Michael Perevozchikov and Thomas Hodapp For Their Advice On Advanced Technology Status

31 Thank You! Questions?