1. Compressed Air Load Reduction
Approaches and Innovations
ACEEE 2001 Summer Study On
Energy Efficiency in Industry
presented by
Mark D’Antonio
ENERGY & RESOURCE SOLUTIONS, INC.
15 Center Place
Stow, MA 01775
Phone: 978-897-4075
www.ers-inc.com
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© 2001 Energy and Resource Solutions, Inc.

2. Air System Overview
Compressor Plant
Plant Auxiliaries
Air Receivers
Distribution System
End Uses and Loads
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3. Air System Overview
Source: DOE Compressed Air Challenge
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4. Demand Side End-Uses
Normal Appropriate Uses
Air Leaks
Artificial Demand due to Excessive Pressure
Inappropriate Uses
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5. Appropriate Uses
Pneumatically Actuated Equipment
Pneumatic Hand tools
Instrument and Control Air
Medical Applications
Process Air
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6. Air Leaks
Monitoring
Ultrasonic Leak Detection
Typical Leaks
Tag #
00-834
00-835
00-836
00-837
00-838
00-839
00-840
00-862
00-863
00-864
00-865
00-866
Room
Machine Dept.
Tool Room
Tool Room
Wax Dept
Wax Dept
Wax Dept
Wax Dept
Wax Dept
Wax Dept
Wax Dept
Wax Dept
Wax Dept
Location
Air drop 2" nipple
Sharp milling machine air gun
Sharp milling machine regulator
Assembly line- hose to air gun
Assembly line regulator
Solubles area air gun
Wax press #009
Wax press #010
Wax press #006
208 Tank #3
Wax Press #004
Wax Press #003
(psi)
105
105
105
65
45
45
87
95
105
35
105
105
CFM
2.5
3.8
1.3
1.6
1.1
1.6
2.1
2.3
5.0
1.3
2.5
3.8
Description/Comments
Reducer to iron nipple
Quick connect at air gun
Brass coupling-outlet of regulator
Leak in air hose (taped up at leak)
Regulator at 10' height, undetermined fitting
Brass coupling into air gun 45 elbow
Brass nipple to hose connector at regulator
T connectors underneath unit, several
Back of press-brass nipple into elbow
Oil lubricator at regulator undetermined
Ball valve L into solenoid underneath machine
Brass coupling into solenoid below machine
Leak Repair Procedures
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7. Air Leak Savings Analysis
ERS
Ultrasonic Leak Detection Survey
Results Summary
Facility:
____________ Corp.
Survey Date: April 1, 2001
Leak Repair Cost Summary
Number of leaks detected and tagged:
Estimated CFM attributed to repairable leaks:
176
450.2
Estimated Leak Repair Cost (at $100 per tagged leak):
Additional Materials Required:
contingency
0%
$17,600
$0
$0
Total Leak Repair Cost:
$17,600
Economic Summary
Total Electrical Cost Savings:
EEM Measure Life (Years):
Simple Payback (Years):
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$53,429
3
0.3
Annual Demand and Energy Savings
Peak
kW
Total Existing Usage:
538.9
Total Proposed Usage:
423.5
Annual Savings:
115.4
Cost Savings Summary
Demand
Energy
kW saved:
115.4
kWh Saved per Year:
Rate: $6.72
On-Peak Rate ($/kWh):
Off-Peak Rate ($/kWh):
Total Electrical Cost Savings:
$53,429
Annual
kWh
3,052,863
2,399,874
652,989
652,989
$0.0707
$0.0658
© 2001 Energy and Resource Solutions, Inc.

8. Improving Efficiency of Appropriate Uses
Pressure Reduction
Volumetric Flow Control
Demand Flow Control
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9. Reduce Artificial Demand :
Pressure Reduction
Reduce Artificial Demand
Pressure Reduction
Point of Use Regulation
Central Regulation
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10. Volumetric Flow Control
Nozzles
Air Knives
Air Amplifiers
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11. Demand Flow Control
Interlocked Solenoid Valves
Flow Controllers
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12. Solutions for Inappropriate Uses
Open Blowing - Blowers
Sparging/Agitation - Blowers
Aspirating - Blowers
Personnel Cooling - Fans
Air Powered Diaphragm Pumps - Electric Powered Pumps
Induced Vacuum Systems - Vacuum Pump
Cabinet Cooling - Blowers/Heat Pipe
Condensate Drains - Airless Float-Activated Drains
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13. Solutions for Inappropriate Uses
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14. Case Study - Automotive Sealing Systems
Compressor Plant
Manufacturer
Sullair
Worthington
Worthington
Gardner Denver
Gardner Denver
Type
Rotary Screw, Single-Stage, Modulating
Rotary Screw, Single-Stage, Modulating
Rotary Screw, Single-Stage, Modulating
Rotary Screw, Single-Stage, Modulating
Rotary Screw, Single-Stage, Modulating
Size
(HP)
150
150
150
150
150
Full
Load
CFM
616
600
600
625
625
Line
Average Percent Loading
Average CFM
Pressure
1st Shift 2nd Shift 3rd Shift 1st Shift 2nd Shift 3rd Shift
(psi)
90%
90%
90%
554.4
554.4
554.4
105
44%
44%
44%
271.0
271.0
271.0
105
18%
18%
18%
110.9
110.9
110.9
105
92%
78%
78%
566.7
480.5
480.5
105
57%
57%
57%
351.1
351.1
351.1
105
1,854
1,768
1,768
kW
Facility Compressed Air Usage: 538.9
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kWh
3,052,863
© 2001 Energy and Resource Solutions, Inc.

15. Case Study
Compressor Performance
150 HP Rotary Screw - single stage, inlet modulation,
air-cooled, premium efficiency motor
110 PSI
capacity
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
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CFM
616
554
493
431
370
308
246
185
123
62
0
% HP
110%
100%
91%
81%
71%
62%
52%
42%
32%
23%
13%
BHP
165
150
136
121
107
92
78
63
49
34
0
motor
eff.
0.945
0.942
0.938
0.935
0.932
0.928
0.925
0.922
0.918
0.915
0.000
KW
130.25
119.19
108.04
96.82
85.52
74.13
62.66
51.11
39.48
27.76
0.00
KW/CFM
0.211
0.215
0.219
0.225
0.231
0.241
0.254
0.277
0.320
0.451
0.000
© 2001 Energy and Resource Solutions, Inc.

16. Case Study
Air Leak Resolution
ERS performed a compressed air survey using ultrasonic leak detection
equipment and tagged one hundred seventy six (176) compressed air leaks
throughout the facility. The majority of these leaks were located at connection
points of fittings, filters, lubricators, regulators, control valves, and hand blowoff guns.
Most of the leaks were easily repaired. Leaks at threaded connections were
repaired by simply backing off the fitting, applying thread sealant, and
reassembling. Where parts had failed, such as hoses and filter bowls, new
replacement parts were installed.
We estimate the diversity of compressor loading and, utilizing a performance
curve for the size and type of compressor involved, predict energy losses due
to the leaks observed.
Total
Cost
$
Energy
Savings
kWh
Demand
Savings
kW
Annual
Savings
$
$14,960
652,989
115.4
$53,429
Simple Payback (years): 0.3
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17. Case Study
Efficient Air Nozzles
Blow-off and part positioning on selected equipment is achieved with a steady
stream of high velocity compressed air. The compressed air is delivered
through copper tubing focused on the desired locations. These machines
currently use 1/16” copper tubing to deliver air streams at 95-100 psi for part
positioning and feeding. At 100 psi, such an orifice will deliver just under 6.5
CFM.
Installation of efficient air nozzles was recommended to meet the process
requirements but with significantly reduced compressed air consumption. An
efficient air nozzle at similar pressure will consume only 4.5 CFM of
compressed air. These nozzles are designed to significantly reduce
compressed air consumption, thereby reducing compressor runtime.
Total
Cost
$
Energy
Savings
kWh
Demand
Savings
kW
Annual
Savings
$
$5,180
79,698
10.3
$5,482
Simple Payback (years): 0.9
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18. Case Study
Install Air Solenoid Valves
There is a wide array of distributed equipment in the facility that requires
compressed air. During non-producing periods, some of this point-of-use
equipment continues to consume air and waste energy. Air loss at the
equipment during non-producing times can be curtailed by controlling the
supply to the equipment.
Compressed air supply should be controlled by installing solenoid valves that
are electrically interlocked with machine operation.With such an installation,
compressed air can be supplied to the equipment only when it is required for
operation, eliminating waste during machine downtimes.
Total
Cost
$
Energy
Savings
kWh
Demand
Savings
kW
Annual
Savings
$
$3,650
121,499
na
$8,357
Simple Payback (years): 0.4
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19. Case Study
Flow Controller/Reduce Pressure
The existing compressed air system pressure setpoint of 105 psi is currently
required to meet the facility demand. This pressure setting is necessary to
account for pressure band fluctuations typical to compressed air systems with
large demand, inadequate storage and no precise flow controlling equipment.
Pressure swings of 10 psi are common. Subsequently, system pressures are
set artificially high to ensure demand requirements at the point of use
equipment.
Installing a flow controller and storage capacity will solve this problem and
save energy. Flow controllers with sophisticated sensing and flow response
capabilities allow for delivery of pressures within a two psi band. This narrow
band allows demand side delivery pressures to be reduced considerably,
lowering overall compressed air consumption and reducing compressor run
times.
Total
Cost
$
Energy
Savings
kWh
Demand
Savings
kW
Annual
Savings
$
$40,600
72,724
60.6
$9,850
Simple Payback (years): 4.1
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20. Case Study
Install Sequencing Control
The facility’s compressor plant is composed of multiple rotary screw
compressors operating continuously in modulation mode. Each compressor
operates on local controls; no central sequencing controls exist. Installing a
master sequencing control system to network the compressors together will
allow for dynamic optimization of the system as a function of demand.
Networking multiple compressors with a microprocessor based sequencing
controller facilitates system optimization by minimizing compressor
horsepower to meet the load.
The controller dynamically monitors system demand and continually adjusts
the compressors’ operating sequence. The controller will select horsepower in
a programmable manner to best match available compressor capacity,
minimizing compressor part-load operation and maximizing system efficiency.
By establishing a base/trim profile, all compressors on line are operated fully
loaded before the next compressor is brought online in the system.
Total
Cost
$
Energy
Savings
kWh
Demand
Savings
kW
Annual
Savings
$
$43,405
657,842
na
$45,246
Simple Payback (years): 1.0
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21. Case Study
Install Blowers for Blow-Off Operations
On several extrusion lines, compressed air is currently used for blow-off drying
as the product exits the cooling tanks. Additionally, blow-off is used as the
product exits flocking stations to remove excess flock. The same function can
be provided at a much lower operating cost with centrifugal blower systems.
Installation of three centralized blower and air knife/nozzle systems to supply
blow-off air to the extrusion lines will result in lower operating costs. Blower
systems that deliver high volumes of lower pressure air directed with air knife
and nozzle systems are effective and economical compared to compressed air.
Total
Cost
$
Energy
Savings
kWh
Demand
Savings
kW
Annual
Savings
$
$79,278
683,940
220.9
$64,846
Simple Payback (years): 1.2
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22. Conclusions
Optimize Appropriate End-Uses
Eliminate Inappropriate End-Uses
Reduce Artificial Demand
Pressure and Pressure Drop Reduction
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23. Questions and Comments
ACEEE 2001 Summer Study On
Energy Efficiency in Industry
Compressed Air Load Reduction
Approaches and Innovations
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© 2001 Energy and Resource Solutions, Inc.