Refrigeration Screw Compressor Controller Introduction Portland, Oregon June 28, 2017 Doug Scott VaCom Technologies
Topics New Controller Introduction Suction Group Control VaCom Refrigeration Approach Economics 2
About VaCom Industrial refrigeration focus Food and beverage, refrigerated warehouses Retrofits and new construction Performance, safety and economics drivers Control Optimization Performance Analytics 3
Refrigeration Screw Compressor Controller For existing refrigeration screw compressor retrofits, such as: FES Frick Mycom Sullair Rockwell hardware CompactLogix L16ER controller Panel View Plus 7 10 terminal VaCom software Designed for integration with ControlLogix system controls 4
Features UL Listed, NEMA 4 Flexible, replaceable IO History trends Shutdown event capture Mechanical high pressure safety Control Capability High and low pressure safety Oil pressure safety Manual/local/remote modes Recycle control Capacity control: slide valve/vfd, local or remote Electronic liquid injection control Motor load limit (VFD integration) Slide valve/mass flow linearization Saturation temperatures and superheats Oil separator velocity limiting Warnings and alarms 5
Benefits Local hardware availability Low service cost Rockwell reliability Long life-cycle hardware Strong integration between SCC and system controls Better control, less hunting and cycling Focused design philosophy, intended for integration: Not intended to control other compressors or equipment Not a web server Not a huge screen 6
Suction group control Compressor control means suction group control Compressor groups are rarely in automatic control Across industry; operator typically turns on/off Even in new plants 7
Suction group control All compressors must be in remote supervisory control cannot be half automatic Reasons compressors are put in local control: Not maintaining proper pressure one problem is too many Special attention needed during daily or weekly start-ups Not controlling efficiently vs. good operator knowledge Multiple unloaded compressors Wrong set of compressors Loss of communication with compressor Too-rapid compressor cycling Once in local, usually stays in local 8
Suction group control Efficient automatic control requires: Best combination of compressors in each capacity step Correct trim compressor in each step (only one) Plus ability to have dual trim for load transients Calculated step-down to the next capacity step Ability to deal with unavailable compressors Setpoint automation plant specific integration 9
Persistent operation and savings 1. Reliable compressor controller 2. Effective supervisory suction group control 3. Monitoring and analysis capability 10
Refrigeration control and information Plant/ Enterprise Services -System Design -Energy Analysis -Economics -Manufacturing Optimization -Enterprise Integration Monitoring and Analytics EnergyDashboard Services Performance Analytics and Continuous Improvement Process Alarms and Health Monitoring Support Services System Level Controls Plant Control -- Multiple Systems Wider Integration, Advanced UI, Broader Safety Systems System Level Controls Suction Group Control Air Units Machine Level Controls Compressors Condensers Vessels Ammonia Safety Integration Chillers Process Loads 11
Project phase 1: Define opportunities and expectations Detailed hourly modeling Facility and systems Production/operations Controls and setpoints Multiple measures Savings-incentives-cost-ROI Facility kwh Usage 450,000 400,000 350,000 300,000 250,000 200,000 150,000 100,000 50,000 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Actual (2013) Actual (2014) Simulation Base Case Simulation Combo Site Energy Baseline Source Energy DEER Peak Peak Lighting HVAC/Refrig. Energy Energy Electric (kwh) N. Gas (Therms) Total (MBtu) Total (MBtu) EUI (kbtu /sf/yr) Demand * (kw) Demand (kw) Electric (kwh) Electric (kwh) Total (MBtu) Reduction (kwh) Run 1 Base Case (Existing Operation) 2,771,537 0 9,459 28,378 788.3 349.83 520.5 138,164 2,633,373 8,988 Run 2 Baseline 2,681,524 0 9,152 27,456 762.7 328.02 465.1 138,164 2,543,360 8,680 Run 3 EEM 1: Floating Head Pressure with Variable Setpoint Control 2,520,310 0 8,602 25,805 716.8 325.44 465.1 138,164 2,382,146 8,130 161,214 Run 4 Run 3 + EEM 2: De scale Existing Condenser 2,461,187 0 8,400 25,200 700.0 316.37 443.8 138,164 2,323,023 7,928 220,337 EEM 2: De scale Existing Condenser 59,123 Run 5 Run 3 + EEM 3: New Condenser 2,453,708 0 8,375 25,123 697.9 312.56 419.7 138,164 2,315,544 7,903 227,816 EEM 3: New Condenser 66,602 Run 6 Run 5 + EEM 4: Variable Speed Condenser Fan Control 2,402,270 0 8,199 24,597 683.2 307.99 419.7 138,164 2,264,106 7,727 279,254 EEM 4: Variable Speed Condenser Fan Control 51,438 Run 7 Run 6 + EEM 5: Replace VRTX System with Chemical Treatment System 2,350,236 0 8,021 24,064 668.4 302.05 413.7 138,164 2,212,072 7,550 331,288 EEM 5: Replace VRTX System with Chemical Treatment System 52,034 Run 8 Run 7 + EEM 6: Floating Suction Pressure Control on LT Suction Group 2,337,155 0 7,977 23,930 664.7 300.09 413.7 138,164 2,198,991 7,505 344,369 EEM 6: Floating Suction Pressure Control on LT Suction Group 13,081 Run 9 Run 8 + EEM 7: LT Compressor Sequencing 2,141,279 0 7,308 21,924 609.0 272.61 413.7 138,164 2,003,115 6,837 540,245 EEM 7: LT Compressor Sequencing 195,876 Run 10 Run 9 + EEM 8: Floating Suction Pressure Control on MT Suction Group 2,127,957 0 7,263 21,788 605.2 270.63 411.1 138,164 1,989,793 6,791 553,567 EEM 8: Floating Suction Pressure Control on MT Suction Group 13,322 Run 11 Run 10 + EEM 9: Retrocommissioning of Subcooler 2,095,060 0 7,150 21,451 595.9 269.24 414.2 138,164 1,956,896 6,679 586,464 EEM 9: Retrocommissioning of Subcooler 32,897 Run 12 Run 11 + EEM 10: Blast Freezer Fan Variable Speed Control 1,930,259 0 6,588 19,764 549.0 251.82 414.2 138,164 1,792,095 6,116 751,265 EEM 10: Blast Freezer Fan Variable Speed Control 164,801 Run 13 Run 12 + EEM 11: Holding Freezer Fan Variable Speed Control 1,869,066 0 6,379 19,137 531.6 246.42 406.9 138,164 1,730,902 5,908 812,458 EEM 11: Holding Freezer Fan Variable Speed Control 61,193 Run 14 Run 13 + EEM 12: Defrost Termination Control 1,805,619 0 6,163 18,488 513.5 239.20 401.4 138,164 1,667,455 5,691 875,905 EEM 12: Defrost Termination Control 63,447 Run 15 Combo1: EEMs 1, 3 through 12 1,805,619 0 6,163 18,488 513.5 239.20 401.4 138,164 1,667,455 5,691 875,905 Run 16 Run 15 + EEM 13: New LT Compressor 1,595,311 0 5,445 16,334 453.7 213.39 421.3 138,164 1,457,147 4,973 1,086,213 EEM 13: New LT Compressor 210,308 Run 17 Run 16 + EAM 14: Replace R 22 with R 507 1,745,060 0 5,956 17,868 496.3 237.90 449.6 138,164 1,606,896 5,484 936,464 EEM 14: Replace R 22 with R 507 (149,749) Run 18 Combo: EEMs 1, 3 through 14 1,745,060 0 5,956 17,868 496.3 237.90 449.6 138,164 1,606,896 5,484 936,464 Run 15: 0 Run 15: 88.82 Run 15: 875,905 12
Project phase 2: Control implementation Development process Turnkey installation Safety integration Training Fine-tuning 13
Project phase 3: Monitoring expected vs. actual performance Monitor operation, report exceptions, manage actions Metrics for systems, compressors, suction groups Examples: Statistic: weighted average part load ratio Trend: VFD vs. slide valve operation 14
Compressor energy savings Run the right compressors for each capacity step Optimize use of unequal capacities Minimize unloaded operation All loaded except trim compressor Optimum step-down decisions Setpoint automation Active floating setpoint Process inputs Variable speed vs. slide valve System-specific economics Use variable speed on trim compressor(s) 15
System energy savings Reduce compressor (and refrigerant) lift 1 degree = 2% energy Lowest discharge (but optimize tradeoffs) Highest suction (but optimize tradeoffs) 16
Economics Refrigeration system energy cost savings potential Compressor savings from 5% to 20% Overall refrigeration system savings 10% to 40% Lesson Learned #1: Start with reliable Compressor Controllers 17
Q&A dscott@vacomtech.com 18