Deep Dive Into Process Efficiency AEP November 14, 2017

Transcription

1 Deep Dive Into Process Efficiency AEP November 14, 2017 Kelly Kissock Ph.D., P.E. Department of Mechanical and Aerospace Engineering / Renewable and Clean Energy University of Dayton, Dayton Ohio, U.S.A. jkissock1@udayton.edu

2 Three Steps To Energy Efficiency

3 Three Steps To Energy Efficiency 1. Develop Baseline 2. Identify and Quantify Savings Opportunities 3. Sustain Efforts Using Sustainable Investment Strategies

4 Baseline

5 Baseline Graph Your Data Estimate Electricity and Fuel Use by Equipment

6 Interpret Electricity Billing Data 12,000 10,000 8,000 Demand (kw) 6,000 4,000 2,000 0 Jan- 00 Feb- 00 Mar- 00 Apr- 00 May- 00 Jun- 00 Jul- 00 Aug- 00 Sep- 00 Oct- 00 Nov- 00 Dec- 00 Identify and correct anomalies

7 Interpret Electricity Billing Data Identify billing errors

8 Interpret Electricity Billing Data Demand (kw) ,600 1,400 1,200 1, Energy (kwh/day) /22/1994 2/24/1995 4/26/1995 6/26/1995 9/26/ /22/1995 1/25/1996 3/26/1996 5/24/1996 7/26/1996 9/25/ /22/1996 Actual Demand (kw) Billed Demand (kw) Energy (kwh/day) Seasonal demand charge

9 Interpret Electricity Billing Data 2,000 25,000 Demand (kw) 1,500 1, ,000 15,000 10,000 5,000 Energy (kwh/day) 0 0 6/6/1995 8/7/ /6/ /6/1995 2/6/1996 4/4/1996 6/6/1996 8/6/ /7/ /6/1996 2/6/1997 4/7/1997 Demand (kw) Energy (kwh/day) Demand relatively constant but energy use driven by production

10 Graph Electricity vs Production

11 Interpret Fuel Billing Data Fraction for production = 310 / 430 = 72% Fraction for space heating =

12 Graph Fuel Use Versus Temperature High Data Scatter = Poor Control Observation: heating energy varies by 3x at same temp Discovery: didn t close shipping doors

13 Estimate Electricity and Fuel Use by Equipment 1) Estimate energy use from: rated power frac loaded operating hours 2) Calibrate sum against measured total energy use Equipment Rated Power Frac Loaded Oper Hours Elec Use (hr/yr) (kwh/yr) AC #1 50 hp 90% 5, ,500 Lights 10 kw 100% 6,000 60,000 Other 10,000 Utility Bill Total = 257,500 Equipment Rated Input Frac Loaded Oper Hours Gas Use (Btu/hr) (hr/yr) (MBtu/yr) Boiler 1 1,000,000 70% 5,000 3,500 Make Up #1 500, % 2,000 1,000 Other 500 Utility Bill Total = 5,000

14 Graph Electricity And Fuel Use by Equipment Estimated Electrical Use Breakdown 20% Vacuum Pumps Process Blowers/Fans 18% Lighting 17% Dust Collectors 12% Sanders 12% Other Process Motors 8% Air Compressors 6% Process Heating 5% Other 2% Estimated Natural Gas Use Breakdown 0% 12% 24% 36% 48% 60% Other Fuel Using Equipment Gas Fired Heater Endo Generators Sterlco Water Heater 13% 12% 11% 51% Potable Water Heater 1% 0% 10% 20% 30% 40% 50% 60%

15 Identify and Quantify Savings Opportunities

16 Identify and Quantify Savings Opportunities 1. List energy systems in your facility 2. Look for savings in conversion, distribution and end-use of each system 3. Improve part-load efficiency of each system

17 HVAC Systems with Savings Opportunities Lighting Zone temperature Outdoor air Fan system Pumping system Cooling system Boiler system Ask Two Questions 1) Is system working as intended? 2) Can control be improved?

18 Industrial Systems with Savings Opportunities

19 Components of Energy Systems Energy Supply Conversion Distribution Use Energy Use Inside-Out Analysis Approach

20 Name an Energy Saving Opportunity in Each Component of Some Energy System 1 Conversion 2 Distribution 3 End use

21 Inside-out Approach to Compressed Air: Reduce Blow-off with Solenoid Valves Flow from open tube (scfm) = 11.6 (scfm/lbf) x [Diameter (in)] 2 x Pressure (psia) Example Install solenoid to shut-off blowoff from 3/8-in pipe at 100 psig 80% of time Flow Savings = 11.6 (scfm/lbf) x [3/8 (in)] 2 x 115 psia x 80% = 150 scfm Cost Savings = 150 scfm / (4.2 scfm/hp x 0.90) x 0.75 kw/hp x (1-0.50) x 6,000 hr/yr x $0.10 /kwh = $8,933 /yr Cost of 3/8-inch solenoid valve = $100 Plant manager taking charge!

22 Reduce Blow off with Air-Saver Nozzles Nozzles maximize entrained air and generate same flow and force with ~50% less compressed air Example Add nozzle to 1/8-in tube at 100 psig Flow Savings = 11.6 (scfm/lbf) x [1/8 (in)] 2 x 115 psia x 50% = 10.4 scfm Cost Savings = 10.4 scfm / (4.2 scfm/hp x 0.90) x 0.75 kw/hp x (1-0.50) x 6,000 hr/yr x $0.10 /kwh = $620 /yr Nozzles cost about $10 each

23 Inside-out Approach to Compressed Air: Identify Leaks Using Ultrasonic Sensor

24 Automatic Sequencer Control: VSD Always Trim VSD compressor IS always trim compressor

25 Reduce Excess Electric Lighting Known Measured = 50 fc Required = 30 fc Action Disconnect (1- fc req /fc mea ) % of fixtures Savings Disconnect = (1 fc req / fcmea) = (1 30 / 50) = 40% of fixtures

26 Position Task Lighting Above Work Areas

27 Reposition Lights Below Scaffolding

28 Paint Ceilings White

29 Replace Metal Halide with High Bay Fluorescent Lights High bay fluorescent (HBF) lights: Reduce energy use by 50% or more Improve CRI Reduce maintenance costs Stabilize light level Improve light distribution Can be turned on/off as needed, w/ occupancy or w/photocells

30 Replace Fluorescent with LED LEDs use 25% less energy than fluorescents, but biggest advantage may be dimming. Control Opportunities: 77 W 55 W 1) Dimming increases sky lighting savings. Working hour savings potential from LightSim: On/Off control: 86% Dimming control: 93% 2) Dimming perimeter lights

31 Reduce Steam Demand Insulate hot surfaces at end use Cover uninsulated tanks

32 Fix Steam Traps Steam traps are automatic valves that discharge condensate from a steam line without discharging steam. If trap fails open, steam by-passes heat exchanger and releases heat in condensate return system If trap fails closed, condensate fills the heat exchanger and chokes-off heat to process. Fixing failed steam traps is highly costeffective.

33 Insulate Pipes and Tanks Insulate Steam pipes Condensate return pipes Condensate return tanks Deaerator tank Valves

34 Reduce Excess Air by Adjusting Air/Fuel Linkage Most boilers use mechanical linkages between natural gas supply valves and combustion air inlet dampers. Unfortunately, linkages seldom hold air/fuel ratio constant over firing range. Adjust linkages so smallest excess air is 10%.

35 Which Component Has the Biggest Bang for the Buck? 1. Conversion 2. Distribution 3. End use

36 Savings Multiply From Inside-Out Inside-out Efficiency Savings (kwh) Reduce pipe friction Pump 70% 1.43 Drive 95% 1.50 Motor 90% 1.67 Transmission and distribution 91% 1.83 Power plant 33% 5.55

37 Think About Control at Part Load Engineers design systems for maximum load Systems seldom (never) operate at maximum load Energy efficiency at part load varies widely Thus, pay attention to part load control

38 Control (Part-load) Efficiency 100% Worst Fraction Energy Input Bad Good Excellent Fraction Useful Output 100%

39 Inefficient Flow Control By-pass Valve By-pass loop (No savings) By-pass damper (No savings) Valve/damper/vanes (Small savings) Intermittent Flow (Small savings)

40 Efficient Flow Control Close By-pass Valve dp VFD Trim impellor for constant-volume pumps Slow fan for constant-volume fans VFD for variable-volume pumps or fans

41 VFD Fan/Pump Control Strategies DP Pset,outlet B A For 50% Flow B: Fan/pump outlet C C: Supply duct/pipe Pset,duct Pset,zone = 0 D D: Critical zone/valve reset V 2 = V 1 / 2 V 1 V

42 Air Compressor Control Savings if FC = 25% Savings if FC = 75% Savings from improving control are biggest on under-loaded (trim) compressors

43 Part-load Control Determines Operating Strategy for Multiple Units

44 Air Compressor Efficiency Increases With Load

45 Run Minimum Number of Compressors

46 Boiler Efficiency Decreases with Load 90% 85% Efficiency 80% 75% Ts=300F Ts=400F Ts=500F 70% Excess Air (%) Efficiency highest at LOW EXCESS AIR and LOW STACK TEMPERTURES Reduce excess air by improving combustion air control Reduce stack temperature by operating at lower firing rate or cleaning heat exchanger surfaces

47 Run Maximum Number of Boilers Efficiency highest at lowfire Run multiple boilers at midfire to increase efficiency Run 1 boiler at high fire: Eff = 81% Run 2 boilers at mid-fire: Eff = 82%

48 Chiller Efficiency Varies with Load Constant-speed: efficiency decreases as load decreases Variable-speed: efficiency increases as load decreases

49 Stage Constant-Speed Chiller LWT Setpoints to Run Fewest Possible Chillers Running 1 chiller at (60% load and 0.30 kw/ton) instead of 2 chillers at (30% load and 0.37 kw/ton) saves 19%.

50 Stage Variable-Speed Chiller LWT Setpoints to Run Maximum Possible Chillers Running 2 chillers at (40% load and 0.22 kw/ton) instead of 1 chiller at (80% load and 0.27 kw/ton) saves 19%.

51 If Variable and Constant-Speed Chillers Employ Controller So Variable is Always Trim Size VS 125% bigger than next biggest chiller to avoid control gaps. Depending on load, controllers save 5-10%

52 List 2 Part-Load Control Opportunities to Investigate in Your Facility 1. 2.

53 Sustain Efforts Using Sustainable Investment Strategies

54 Reinvest Part of Savings to Achieve Net-zero Co 2 At Net-zero Cost

55 Sustainable Manufacturing and Buildings Energy savings pays for renewable energy Net CO 2 zero at net zero cost!

56 Develop Baseline Graph data Estimate energy use by equipment Summary Identify and Quantify Savings Opportunities Think in terms of energy systems Break down energy systems into end use, distribution and conversion Pay attention to part load control Maximize Efficiency Using Sustainable Investment Strategies Reinvest part of savings into more savings and renewable energy

57 What s New? Data analytics Advanced rules-based controls Machine-learning control

58 Temperature-Based Economizer Control

59 Data Analytics: Plot MAT-RAT vs OAT-RAT Working Economizer Cooling Hours 22% Heating Hours 14% Modulating Hours 27% Integrated Hours 37%

60 Data Analytics: Malfunctioning Economizer Source: Hourly logged data. 10/21/ /15/2016

61 Advanced Rules-based Control: Use CO 2 Sensor in Return Air to Reset Foa,min CO 2 Sensor Foa,min,CO 2 = (ppm,return - ppm,outdoor) (ppm,upper limit ppm,outdoor) When Foa,min reduced by 50% for 20% of time when Toa>Tr, outdoor air cooling savings = 10%

62 Data Analytics + Advanced Rules Based Controls:

63 If Mean Damper Position < 70% Open, Reduce Static Set Point Baseline: Pset = 1.5 Dampers 65% Open Post Baseline: Pset = 1.0 Dampers 67% Open

64 Savings From Reducing Pset from 1.5 to 1.0 Savings: 26%

65 Fan Outlet Control to Turkur/Ma Reset Control 51% fan energy savings

66 Zone CO 2 Sensor Duct Static Pressure Reset Duct Static Pressure Before and After Reset Vmin Measured Savings

67 Machine-Learning Control Run efficiently through coaching or learning Rules-based control requires explicit knowledge about systems Machine learning control uses neural networks, clustering techniques + classical optimization to learn optimum behavior

68 Machine-Learning Control Example Global optimization analyzes all possible pumping combinations and chooses the combination closest to the cost optimized value.

69 Industrial Assessment Center Program Sponsored by U.S. Department of Energy (DOE) Began during 1970 s energy crisis 24 centers at universities throughout the U.S. 20 no-cost assessments per year for mid-sized manufacturers Goals Help industry be more resourceefficient and cost-competitive Train new energy engineers Advance practice and science of energy efficiency

70 Qualifying For A Free IAC Assessment To qualify for a free assessment, you must: Be a water utility or a manufacturer with SIC code between Have total annual energy costs between $100,000 - $2.5 million

71 Sponsored by Ohio Development Services Agency Ohio Lean Buildings Program 4 universities and 6 consulting companies Goals Make Ohio s buildings more energy-efficient and costcompetitive Train new energy engineers Advance practice and science of energy efficiency

72 Qualifying for an OLB Assessment To Qualify for a Building Assessment, you must: Commercial and institutional buildings larger than 10,000 ft 2 State of Ohio pays for 50% of assessment Client qualifies for lowinterest loan for implementation

73 University Of Dayton Industrial Assessment Center & Ohio Lean Buildings Program U.S. Department of Energy and State of Ohio Sponsored Programs go.udayton.edu/iac (937)