Compressed Air Principals and Self-Assessment Tools. Jeff Becker, MnTAP Technical Director June 28, 2011 for EPA Region 7

Transcription

1 Compressed Air Principals and Self-Assessment Tools Jeff Becker, MnTAP Technical Director June 28, 2011 for EPA Region 7

2 Agenda MnTAP Intro Compressed air basics Fundamentals Equipment and power curves Assessment description How to assess your system quickly Recommendations Your questions 2

3 MnTAP Services Minnesota Technical Assistance Program University of Minnesota Free to Minnesota businesses Focused on waste reduction & energy efficiency Customized technical assistance Site visits Teams Technology demos and pilots Interns 3

4 Why Compressed Air? Affects your bottom-line $$$ US DOE: 50% of compressed air gets used in production Costs ~$13,000/yr to operate 50hp $0.05/kWh rated at 90% efficiency Assumes ideal production utilization (w/ rotary screw 75% loaded) 4

5 Why Compressed Air? Basics Takes 8hp of electricity to produce 1hp of compressed air An audible leak can cost over $1,000 each year Properly designed systems should have less than a 10% pressure drop from the discharge to the point of use 5

6 Opportunity Roadmap Components Supply study Collect compressor and system information Model and size Dryer(s), drain(s) and filter(s) information Receivers Review of compressor system performance Demand study Research pressure loss in the distribution Review tool efficiencies Monitor inappropriate uses 6

7 Supply Study, System Profile Pressure and power sampling Amps Compressor 1 P Amps Compressor 2 Filter Wet Storage Dryer Dry Storage P P 7

8 Air Treatment Dryers Select pressure dewpoint Filters Deliquescent < Heat-activated Desicant < Refrigerant < Regenerative-Desicant < Membrane Efficiency relates to pressure drop Particulate Coalescing Adsorption High purge air loss and delta P = $$$$$ Each contributes to system pressure drop 8

9 Supply Study Compressor details Motor attributes Motor size, efficiency, mechanical drive and control type. Operation Start/stop Load/Unload Variable displacement or inlet valve modulation Operation attributes Cut-in pressure (Load) Cut-out pressure (Unload or off) Dry air quality Drain timers Base and trim loading 9

10 Load & Unload Motor output proportional less air being compressed only 10

11 Load & Unload w/ Unload Control Motor cuts out if system does not load 11

12 Inlet Modulation w/out Unloading 12

13 Inlet Modulation with Unloading Valve closed/motor unloads 13

14 Variable Displacement Valves open to increase effective shaft length 14

15 Variable Speed Drive, VFD or VSD Motor speed proportional to air flow 15

16 Supply Study, System Profile Pressure and power sampling Amps Compressor 1 P Amps Compressor 2 Filter Wet Storage Dryer Dry Storage P P 16

17 Compressor not fully unloading (Short-cycling) Delta P ~ 5 psi

18 Dry Storage Sizing Regulated and dedicated storage Dry Storage Regulator Assume a flow of 100 cfm required for 15 seconds every two minutes: Pressure drop is 124 to 118 psi = 6 psi 450 Gallons Volume = Time * Consumption * 14.2 psi / Delta P Volume = 15/60 min * 100 cfm * 14.2 psi / 6 psi Volume ~ 60 cubic feet 18

19 Demand Study Supplied pressure Distribution Pipe types and diameters Pressure drop Remote storage Review of compressor system operation Equipment Inappropriate uses Cabinet cooling, open blowing, sparging, venturi generation Air tools 19

20 Demand Study Storage Size to trim peak CFM to average CFM Individual workstation storage Compensate needs with a higher stored pressure Pressure drop Critical pressure analysis Required pressure versus actual pressure delivered Worst-case scenarios Line restrictions and diameter reductions 20

21 Compressed Air Assessment Lots of detail and effort Compressed air performance and treatment Controls and pressure levels Load profile Measures changes in demand over work hours Heavy demand during short periods calls for storage Audiometric leak testing Airmaster + air system assessment and analysis software Downloadable and free from the EERE Certification may be required 21

22 Compressed Air Assessment I. GENERAL INFORMATION Facility Name Address Phone No. Self-assessment Best of all, its EASY. Worst of all, its just a snapshot. Contact Person Utility Info (Input) Cost of Electricity $ 8.50 $/kw $ 0.07 $/KWh II. INPUT TABLES Wet Storage (before Dryer) 160 gallons Dry Storage (after Dryer) 0 gallons Plant pressure needed, -psig 100 psig COMPRESSORS Compressor #1 Compressor #2 Other Compressor Manufacturer Other Other Model Compressor type Double-acting Recip. Double-acting Recip. Double-acting Recip. Motor hp Rated capacity at full load P, acfm Control type Start/Stop Start/Stop Start/Stop Base, Trim, or Off? Base Trim Off Full-Load Pressure, psig Cut-Out Pressure, psig OPERATION (during Production) Annual hours Load stopwatch time, min Unload stopwatch time, min Compressor Off time, min OPERATION (no Production) Load stopwatch time, min Unload or off time, min III. OPTIONS INPUT Plant overpressure, -psig Reduce Plant Pressure, -psig OUTPUT TABLES TOTAL Cost to Operate Compressor(s), $ $ 1, $ $ - $ 1, Energy to Operate, kwhs 9, ,999 Compressor efficiency, kw/100 cfm Air Storage Capacity, gallons Est. Average Comsumption, scfm Leak Rate, scfm Leaks, est. % 3% 0 Repair Half of Leaks Savings $ $ - $ - $ Reduce Plant Pressure Savings $ $ $ - $ Potential Unload Timer Savings None None None $ - Investigate larger storage? YES No No YES SAVINGS $ NEW ANNUAL COST $ 1,

23 Compressed Air Assessment Fairly simple to complete 28 inputs Only 8 of 28 are require real effort Fairly simple to measure Requires a stopwatch and manuals Fairly simple to interpret Estimates facility compressed air cost and energy use Efficiency measures Reduce leaks Reduce plant pressure Install storage Configure an unload timer 23

24 Compressed Air Opportunity Examples Install zero-loss condensate drain valves A few devices eliminates wasted air Achieved savings of 7,200 kwh ($1,084 annually) Adding storage Facility required 3,500 gallons Savings of 103,800 kwh ($16,744 annually) Leak repair Facility had a 27% leak rate Costs over $18,000 annually PM program can net 145,000 kwh savings 24

25 Other Compressed Air Insights Psst every facility has leaks Start a leak PM activity Ultrasonics Perform a yearly drain-down test Replace all drains Opt for zero loss Reduce impact of high-pressure, high-flow devices Install storage with inlet restriction Amplifiers 25

26 Other Compressed Air Resources Compressed Air Challenge Fundamentals of Compressed Air Advanced Management of Compressed Air Systems AirMaster+ Software US Department of Energy Office of Energy Efficiency and Renewable Energy 26

27 Thank you for your Participation! Jeff Becker, Technical Director Office: Mobile: