1. Lowering Your Compressed Air Energy Costs
4/15/2017
Lowering Your Compressed Air Energy Costs
Trey Donze
Mike Hotz
Air Technologies

2. Why Care About Compressed Air?
Compressed air is expensive
Compressed air is essential to plant productivity
Compressed air systems can be effectively managed to improve plant operation
Compressed air systems usually have significant opportunities for efficiency improvement

3. Compressed Air Use in Selected Manufacturing Industries
Compressed Air Energy Use as a Percentage of Total Electricity Use
Food
Metals
Petroleum
Paper
Chemicals

4. Life Cycle Cost of an air compressor
4/15/2017
Life Cycle Cost of an air compressor
Energy cost can account for up to 90% over a ten year working life
Within 12 months, the capital cost is usually exceeded by the running costs
First cost represents the lowest of the three costs
Energy consumption by far is the most significant factor in operating cost of an air compressor
Energy consumption
Installation
Maintenance
Investment

5. Benchmark Your System’s Efficiency
To make an accurate determination of energy savings solutions, it is important to measure your system flow, pressure and kW as well as evaluate any plans for future expansion
This is accomplished by a flow and kW survey

6. Benchmark Your System’s Efficiency
Measure your compressed air requirements
Flow
Pressure
Dew point
kW and kWh
Benchmark your current system’s efficiency kWh/MCF
Receive a detailed report outlining improvements

7. KW Meters

9. 4/15/2017
Typical 24 hrs/day operation with low night shift and high day shift consumption. Steady weekend consumption (leakages).
(64% of installations).
time

11. Five days/week operation, erratic demand fluctuations
4/15/2017
Five days/week operation, erratic demand fluctuations
(28% of installations).
time

12. Energy Reduction Opportunities
Use Efficient Compressor Controls
Reduce Compressed Air Usage
Lower Compressor Discharge Pressure
Efficiently Sequence Air Compressors
Operate and Maintain Compressed Air Equipment at Peak Efficiency

13. % Power Input
% Capacity

14. Use Efficient Compressor Controls
4/15/2017
Use Efficient Compressor Controls
75 HP Lubricated screw compressor
w/ Modulation Control -vs.- 60 HP VSD
Average electrical cost = $0.06 / KWHR
A) 1st shift CFM 2200 HRS/YR
B) 2nd shift 175 CFM 2200 HRS/YR
C) 3rd shift 100 CFM 2200 HRS/YR
75 HP 125 PSIG 60HP 125 PSIG
82.5 Bhp full load power 66 Bhp full load power
320 CFM CFM
91.5% Motor eff. 94%

16. Use Efficient Compressor Controls
4/15/2017
Use Efficient Compressor Controls
75 Hp modulating 60 Hp VSD
250 CFM: 250/320 = 78% (93% Bhp) /290 = 86% (86% Input kW)
175 CFM: 175/320 = 55% (86.5% Bhp) /290 = 60% (61% Input kW)
100 CFM: 100/320 = 31% (79% Bhp) /290 = 34% (38% Input kW)

17. Use Efficient Compressor Controls
4/15/2017
Use Efficient Compressor Controls
75 HP lubricated screw with modulation control
A) First shift CFM:
82.5 Bhp X (.93 factor) X .746kW X $.06 X 2200Hrs = $8,738
.915 Mtr. eff Hp kWh
B) Second shift 175 CFM:
82.5 Bhp X (.865 factor) X .746kW X $.06 X 2200Hrs = $8,127
.915 Mtr. eff Hp kWh
C) Third shift CFM:
82.5 Bhp X (.79 factor) X .746kW X $.06 X 2200Hrs = $7,422
.915 Mtr. eff Hp kWh
Total = $24,287

18. Use Efficient Compressor Controls
4/15/2017
Use Efficient Compressor Controls
60 Hp Variable Speed compressor
A) First shift 250 CFM:
66 Bhp x .746 kW x (.86 factor) x $.06 x 2200Hrs = $5,946
.94 ME Hp kWh
B) Second shift 175 CFM:
66 Bhp x .746 kW x (.61 factor) x $.06 x 2200Hrs = $4,217
.94 ME Hp kWh
C) Third shift 100 CFM:
66 Bhp x .746 kW x (.38 factor) x $.06 x 2200Hrs = $2,627
.94 ME Hp kWh
Total = $12,790

19. Use Efficient Compressor Controls
4/15/2017
Use Efficient Compressor Controls
Total Power Savings:
$24,287 - $12,790 = $11,497 per year
60 HP VSD costs $25,000 for a 2.17 year payback!

20. System running with (2)-125 HP OL/OL compressors
3.7 kWH/MCF
Inconsistent efficiency
System running with (1)-125 HP OL/OL compressors and (1)-75 HP VSD
3.3 kWH/MCF
Nearly constant efficiency

21. Reduce Compressed Air Usage
Eliminate inappropriate air users
Use brushes, blowers, or vacuum systems instead of compressed air to clean parts or remove debris; 
Use blowers, electric actuators, or hydraulics instead of compressed air blasts to move parts;
Use high efficiency nozzles instead of open orifices

22. Reduce Compressed Air Usage
Eliminate inappropriate air users
Use fans to cool electrical cabinets instead of compressed air vortex tubes
Apply a vacuum system instead of using compressed air venturi methods
Use blowers instead of compressed air to provide cooling, aspirating, blow guns, air lances, agitating, mixing, or to inflate packaging

23. Reduce Compressed Air Usage
Minimize unregulated air users
Install regulators
Reduced pressure lowers air consumption
Unregulated users use 47% more compressed air at 110 vs. 70 PSIG
Less equipment wear and tear

24. Reduce Compressed Air Usage
Shut off air to equipment that is shutdown or abandoned
Install automatic solenoid valves
Valve off idled sections of the plant

25. Reduce Compressed Air Usage
Fix Leaks
Leaks can account for 10-50% of the total compressed air usage!
1/8 inch dia. hole = 25 SCFM = $3,000
1/4 inch dia. hole = 100 SCFM = $12,000
3/8 inch dia. hole = 230 SCFM = $26,000
* Based on 8,760 operating $0.07 per kWh energy cost

26. Reduce Compressed Air Usage
Minimize Leaks
Measure leak load to quantify the opportunity
Find the leaks with an ultrasonic leak detector
Tag the leaks
Fix the leaks
Re-measure the leak load to quantify the savings
Develop and on-going leak reduction program

27. Reduce Compressed Air Usage
Reduce plant system air pressure
Unregulated air users and air leaks use 28% more compressed air at 120 vs. 90 PSIG

28. Reduce Compressed Air Usage
Reduce system air pressure
Evaluate the pressure requirements of all compressed air users
Put the small high pressure user on its’ own compressor
Install good compressor sequencing controls
Lower the system air pressure

29. Reduce System Air Pressure
Measure system/component pressure drops
Minimize distribution and component pressure drops
Loop air header
Upgrade, repair or eliminate high delta P components
Upsize piping/hoses
Address large intermittent air “gulpers” that draw the system down with storage and metering valves
Decentralize compressors

30. 4/15/2017
Receiver Sizing
Useful Free Air Stored = V x  P
14.7
V = storage volume (Ft3)
 P = pressure differential (Pressure Drop in Tank)
Example: Pneumatic conveyor requires 200 cfm of 40 psig air for 2 minutes every 10 minutes.
200 X 2=400 CF required useful free air to be stored
 P= =60
400=V X 60/14.7 V= 400 X 14.7/60 = 98 CF = 735 gallons
400 CF/8 minutes=50 CFM to refill
System sees 50 CFM instead of 200 CFM! 10

31. Lower System Pressure to Lower Air Consumption
4/15/2017
Lower System Pressure to Lower Air Consumption
95 psig – 950 CFM air usage
85 psig – 825 CFM air usage
70 psig – 700 CFM air usage

32. Reduce Compressed Air Usage
Reduce system air pressure
Use intermediate controllers with storage to regulate system air pressure
Effective when part of the plant operates at a lower pressure
Lowers air consumption
Does not lower compressor pressure

33. Reduce Compressed Air Usage
Reduce system air pressure
Use effective compressor sequencing, storage, and compressor controls to “regulate” system pressure
Lowers air consumption and compressor pressure
Most energy efficient

34. Sequence Air Compressors

35. Typical System Without a Sequencer
4/15/2017
Typical System Without a Sequencer
Cascading Systems C1 C2 C3 C4
125 PSIG
125
120
unload
115
Individual settings
Large pressure band
Multiple units at part load
Very inefficient
110
115
110
105
load
100
100 PSIG 11 7

36. Sequencers Significantly Improve Efficiency to Minimize Energy Costs
4/15/2017
Sequencers Significantly Improve Efficiency to Minimize Energy Costs
Can regulate system pressure within 3-5 psi
Lower system pressure significantly reduces air demand (leaks and unregulated demand)
Operates the minimum # of compressors to meet the demand
Only one compressor trims at all times
Automatic scheduled system pressure changes and/or start/stop of system
Most efficient compressor sequence order determined from flow data
Can automatically select optimum sequence

37. System Pressure remains consistent as flow rate varies
4/15/2017
System Pressure remains consistent as flow rate varies

38. 4/15/2017
RULE OF THUMB
Power consumption increases 1% for every 2 psi increase in compressor pressure 12

39. 4/15/2017
Sequencers pay for themselves in energy savings by reducing pressure band differentials and lowering air usage
EXAMPLE Hp Compressors Required: 1700 SCFM at 100 Psig
Pressure Switch Settings Between 95 to 125Psig
Pressure Band of 30 Psig
400 Hp x .745 kW/Hp x 8800/year x .06 kWh = $167,387.00
.94 (motor Efficiency)
Reduce Pressure Band by 25 Psig to save 12%=$20,086.00

40. Flow changes but kW does not change proportionally

41. Poor efficiency of a cascaded system due to multiple units at part load

42. Total system energy savings of 20-50% are expected
4/15/2017
Sequencers Can Significantly Improve Efficiency to Minimize Energy Costs
Total system energy savings of 20-50% are expected

43. kW/100 CF stays consistent even under varying loads
4/15/2017
kW/100 CF stays consistent even under varying loads
.32 kW/100CF versus .85 kW/100CF (63% Savings!)

44. Switch to LILO Sequencing with a 5 minute unloaded time

45. Sequencing Significantly Improves Efficiency to Minimize Energy Costs
Basis 3 shift operation, $.06/kWhr, 20 PSI pressure band reduction

46. 4/15/2017
Advanced sequencers provide system flow and pressure data to manage your 4th Utility
System flow and pressure are logged automatically
Determine the most efficient compressor sequence
Useful for peak load shedding
Measure leaks
Spot system/ production problems
Measure equipment/process air consumption

47. ManagAIR® by Air Technologies®
System Report for Ferro 9/7/01 1:59:05 PM
Alarm: No Faults Detected
Current System Readings- Pressure= Flowrate= Sequence=2,1,3
Previous 8hrs Data: Hour1 Hour2 Hour3 Hour4 Hour5 Hour6 Hour7 Hour8
Min Pressure
Avg Pressure
Max Pressure
Min FlowRate
Avg FlowRate
Max FlowRate
Min DewPoint
Avg DewPoint
Max DewPoint
Compressor Data #1 ZT25 #2 ZT25 #3 ZT25 NONE NONE NONE NONE
Delivery Air Press
DP Air Filter
Intercooler Pressure
Oil Injection Press
Delivery Air Temp
Oil Injection Temp
LP Outlet Temp
HP Outlet Temp
HP Inlet Temp
Cooling Medium Inlet Temp
MD Regen Air Out Temp
MD Wet Air In Temp
LP Element Temp Rise
HP Element Temp Rise
Cooling Water Temp Rise
Oil Cooler Approach Temp
Aftercooler Approach Temp
Intercooler Approach Temp
MD Regen Temperature Drop
MD Inlet Temperature Diff
Loaded Hours
Running Hours
Compressor Status UNLOADED LOADED STOPPED
Motor Starts
Link Type MKIII MKIII MKIII
Isolated/Integrated CENTRAL CENTRAL CENTRAL
Full Feature Dew Point
Oil Filter Remaining Lifetime
Oil Filter Total Lifetime
Oil Remaining Lifetime
Oil Total Lifetime
Hours Until Regrease Bearings
Hours Between Bearing Regreasing
Daily System Report and graph faxed or ed to you automatically

48. Good Maintenance Saves Energy
4/15/2017
Good Maintenance Saves Energy
Inlet Filters
Every 4 inches (water) pressure drop reduces the compressor capacity 1%
A dirty inlet filter can rob you of 5% or more! 11

49. Good Maintenance Saves Energy
4/15/2017
Good Maintenance Saves Energy
Dirty Coolers
For every 11oF deterioration in the intercooler approach or increase in water temperature, the power consumption will increase by 1%. 13

50. Good Maintenance Saves Energy
4/15/2017
Good Maintenance Saves Energy
Dirty Coolers
For every 10oF deterioration of the after cooler approach temperature, the dryer load is increased by as much as 46%. 14

51. A dirty oil separator can increase your HP 5%
4/15/2017
Good Maintenance Saves Energy
Dirty Oil Separator
A dirty oil separator can increase your HP 5% 14

52. Energy Reduction Opportunities
Use Efficient Compressor Controls
Reduce Compressed Air Usage
Lower Compressor Discharge Pressure
Efficiently Sequence Air Compressors
Operate and Maintain Compressed Air Equipment at Peak Efficiency

53. Lowering Your Compressed Air Energy Costs
Trey Donze
Mike Hotz
Air Technologies