Energy Efficiency in Compressed Air Systems
Alexander Pavlov
IETC, New Orleans, 20-21/05/10
Atlas Copco in a Snapshot
 A world-leading provider of industrial productivity solutions.
 Products and services range from compressed air and gas equipment,
generators, construction and mining equipment, industrial tools and
assembly systems, to related aftermarket and rental.
 In close cooperation with customers and business partners, Atlas Copco
delivers sustainable solutions for increased productivity through innovative
products and services.
 Headquartered in Sweden, the Group’s global reach spans more than
170 markets.
 In 2009 Atlas Copco had 30 000 employees and annual revenues of
approximately BSEK 64 (BEUR 6.0).
2
The Atlas Copco Organization
Board of Directors
President and CEO
Executive Group Management and Corporate Functions
Compressor
Technique
Oil-free Air
Construction and
Mining Technique
Underground Rock
Excavation
Industrial Air
Surface Drilling
Equipment
Portable Air
Drilling Solutions
Specialty Rental
Gas and Process
Secoroc
Industrial
Technique
Atlas Copco Tools
and Assembly Systems
Motor Vehicle Industry
Atlas Copco Tools
and Assembly Systems
General Industry
Construction Tools
Chicago Pneumatic
Compressor Technique
Service
Road Construction
Equipment
Tooltec
Airtec
Geotechnical Drilling
and Exploration
Rocktec
Customer Centers and Service Providers
3
Worldwide Presence
Production sites
4
Value of Energy in Compressed Air Systems
Some useful facts and figures
 70% to 80% of life cycle costs is energy
Energy Savings
 In EU compressed air accounts for 10% of the
energy consumed by industry
 1 bar lower in pressure, reduces energy by 7%
 Typically, after 5 years leakages can take 20%
of the total air consumption
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Investment 12%
Maintenance 15%
Installation 3%
Energy consumption 70%
CO2 emissions – the big picture
Atlas Copco focus
(95% +)
 Design of
product
6
 Energy use
 Re-use
 Logistics
 Less
electricity
consumption
 Design of
product
Why Atlas Copco
Saving energy is our way of life
A century of innovation in energy saving features
Over 400 patents
7
EU electricity consumption in compressed air
Real consumption in CAS TWh
Share of electricity
In EU the compressed air accounts for 10% of the energy
consumed by industry, 80 TWh/year
Source: Compressed air systems in the European Union, 2001, study by Fraunhofer Institute,
ADEME, ECE, University of L’Aquila
8
Potential contribution to energy savings
% applicability(1)
% gains(2)
Potential contribution(3)
Improvement of drives (high efficiency motors, HEM)
25 %
2%
0.5 %
Improvement of drives (adjustable speed drives, ASD)
25 %
15 %
3.8 %
Upgrading of compressor
30 %
7%
2.1 %
Use of sophisticated control systems
20 %
12 %
2.4 %
Recovering waste heat for use in other functions
20 %
20 %
4.0 %
Improving cooling, drying and filtering
10 %
5%
0.5 %
System installation or renewal
50 %
9%
4.5 %
32.9 % = 30.5 TWh/yr = 0.7 million
tonnes
of CO²/yr
Overall system design, including multi-pressure systems
Reducing frictional pressure losses
50 %
3%
1.5 %
Optimising certain end use devices
5%
40 %
2.0 %
Reducing air leaks
80 %
20 %
16.0 %
More frequent filter replacement
40 %
2%
0.8 %
System operation and maintenance
TOTAL
Table legend:
(1) % of CAS where this measure is applicable and cost effective
(2) % reduction in annual energy consumption
(3) Potential contribution = applicability * reduction
Source: Compressed air systems in the European Union, 2001, study by Fraunhofer Institute,
ADEME, ECE, University of L’Aquila
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32.9 %
From products to solutions
The unique approach
Customer needs
Superior solutions
demand
assessment
Total energy
saving concept
core
technology
optimization
of the room
drive
technology
10
energy
recovery
energy saving
accessories
The Energy Circle
Customer needs
Superior solutions
demand
assessment
energy
recovery
core
technology
optimization
of the room
drive
technology
11
energy saving
accessories
Demand assessment
 System audit:
– Flow measurement
– Pressure measurement
– Power measurement
 Report:
– Simulation of optimal compressor installation
– Simulation of central control system
– Potential energy savings
Overall system design
12
Leak detection
 Ultrasound leak detection
 Report
– Location
– Leak flow
– Equivalent energy loss
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System assessment
AirScan - Tools
Flow
Leak detection
Dewpoint measurement
Measurement box
Power/logging device
Temperature
Hot tapping
14
Flow measurement output
VIP sens
The Energy Circle
Customer needs
Superior solutions
demand
assessment
energy
recovery
core
technology
optimization
of the room
drive
technology
15
energy saving
accessories
Products
Best compression and treatment technologies under one roof
Oil-free scroll compressors
1-15 kW
Oil-free tooth compressors
15-45 kW
Oil-free screw compressors
55-900 kW
Oil-injected screw compressors
5-500 kW
Turbo compressors
500-2500 kW
Matching air treatment equipment
Dryers,filters,drains,separators,etc
ES – energy saving central controllers
Optimization, monitoring, control
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Energy Savings
Specific energy J/l (Hp/cfm)
Atlas Copco has all the technologies available
scroll
tooth
18 kW
centrifugal
screw
55 kW
750 kW
Power (flow)
Appropriate selection can save a lot of energy
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System design : innovations in screw elements
Specific Energy (J/l , Hp/cfm)
Before
1995 - 2008
2000
1990
2003
2006
11kW
22kW 30kW
55kW
90kW 132kW 200kW 300kW
3-5%
3%
56%
1
10 (21.2)
100 (212)
FAD l/s (cfm)
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1000 (2,120)
The Energy Circle
Customer needs
Superior solutions
demand
assessment
energy
recovery
core
technology
optimization
of the room
drive
technology
19
energy saving
accessories
Energy Savings
Typical air demand pattern
l/s
Monday
Tuesday
250
Wednesday
Thursday
200
Friday
Saturday
Sunday
150
Average use 50%
100
50
hour
Measurement and simulation tools are available to calculate precise energy savings in a real environment
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Energy savings with VSD
Power consumption during transition from load to no load with traditional
regulation
Excess energy
Loaded pressure
T
Theory
Actual
T- time for complete system venting
21
time
Unloaded system
pressure
Energy savings with VSD
Power consumption during transition from load to no load with traditional
regulation vs. VSD
Power consumption GA45 L-NL at 50%
40
~80%
30
VSD
20
10
seconds
260
240
220
200
180
160
140
120
100
80
60
40
20
0
0
kW
50
Energy cost per m3 of air at 7 bar(e) (100 psig)
VSD technology can save up to 35% of energy
Specific energy J/L or $/M3
$/M3
scroll
tooth
18 Kw
centrifugal
screw
55 Kw
750 Kw
Flow m3 / min
VSD – Variable speed drives
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Our commitment to VSD technology
0
250
500
750
Company A
Company B
Company C
Company D
Company E
Others : mainly promoting free-standing
Atlas Copco
Widest integrated VSD range (from 7.5 to 900 KW)
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1000 kW
The Energy Circle
Customer needs
Superior solutions
demand
assessment
energy
recovery
core
technology
optimization
of the room
drive
technology
25
energy saving
accessories
Efficiency – Air quality
MD and XD dryers – energy-less air drying
 Heat of compression is used for drying
 No external energy or purge is required
 Very low pressure drops
Energy savings between 5 and 20% are possible !
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Dryer energy consumption (-20oC, -4°F PDP)
% of compressor power
25%
19.53%
20%
15%
10%
7.70%
5%
2.30%
0.02%
0%
BD heat reactiveted
CD purge reactivated
XD 0 purge HOC
Type of dryer
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MD HOC
The Energy Circle
Customer needs
Superior solutions
demand
assessment
energy
recovery
core
technology
optimization
of the room
drive
technology
28
energy saving
accessories
Energy savings through optimization
compressor
1
compressor
2
compressor
3
compressor
4
Net pressure
PRESSURE BAND CASCADE
CENTRAL
CONTROL
LOCAL CONTROL
Average
pressure
Required minimum
pressure
HIGH COSTS
Time
LOW COSTS
 ES controls the net pressure
–
Net pressure is guaranteed while compressors run at lowest required pressure
 Lower pressure by 1 bar reduces energy by 7%
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Automatic selection of “Best Size” compressor
Big compressor
Pressure
 Net pressure drops fast
Time
Pressure
 Net pressure drops slowly
Time
30
Small compressor
Optimization of VSD compressors
VSD 2: ~ 70%
ES optimization
Flow
Flow
Local control
VSD 2: ~50%
Efficient?
VSD 2: 50%
VSD 1: 30%
VSD 1
Time
VSD 2
Flow (l/s)
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SER (J/l)
SER (J/l)
Time
VSD 1
VSD 2
Flow (l/s)
Local control
ES optimization
VSD 2: 90%
VSD 2: 50%
Flow
Flow
Optimization of Turbo’s and VSD
Turbo 2: 50%
(blow-off ~20%)
Turbo 2: 80%
Efficient?
(blow-off 0%)
Turbo 1: 100%
Turbo 1: 100%
(blow-off 0%)
(blow-off 0%)
Time
Time
Turbo 1
Blow-off
SER (J/l)
SER (J/l)
Turbo 2
Blow-off
…..
SER (J/l)
SER (J/l)
…..
VSD
Flow (l/s)
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Turbo 2
VSD
Flow (l/s)
Turbo 1
Carbon Zero
The unique approach
The new
milestone
Recovery
‘Carbon Zero’
demand
assessment
“net zero energy”
optimization
of the room
core
technology
efficient air
treatment
drive
technology
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Measured parameters TÜV test
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Type test of ZR 55-750 range with built-in
energy recovery systems
Comparison of the electrical energy
consumption with heat energy recovered
Certified results
 “100% of the electrical energy
consumed could be recovered”
 “ net power (energy) consumption of
the ZR compressor with built-in energy
recovery at specific design conditions
is zero”
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Introducing Carbon Zero
10% losses in radiation, etc.
100%
Electrical energy
input converted
to heat
Direct energy
recovery 90%
102
Atmospheric
energy 12%
Energy in
atmospheric air
(latent heat)
15%
Released due to condensation in coolers
Result – Net Zero energy consumption
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Carbon Zero principal build-up
ZR Energy recovery
LP element
HP element
ZR Energy recovery
70-90°C (158-194°F)
Recovered energy at 10 bar(e)
(145 psig)
9%
Oil cooler
12%
Intercooler
37%
Aftercooler
42%
Thermostatic
valve
20-40°C (68-104°F)
ER control unit
Water circuit
37
Components of the energy recovery systems
Secondary cooling
water system
T
Heat consumer
H
H
H
H
H
T
H
H
ZR
PI
TI
H
H
Control unit scope is within the dashed line.
Outside is customer’s scope.
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What makes ZR compressor unique
 Compared to oil-injected screws
– ZR compressors have much higher temperatures due to which they can recover 100% of
the electrical energy as heat, under design conditions. Watercooled OIS can recover +/70%
 Compared to turbos
– Lower temperatures in turbos restrict energy recovery severely
– Interstage energy recovery can create instability
– At reasonable temperatures energy recovery is 30-35%
 Compared to other oil-free screws
– Others are not recovering energy from oil coolers and jackets, thus losing 20-25%. So
energy recovery with competitors OFS could be at best 80%
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Applications
Showers
Boiler feed
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Space heating
Some high level steam applications
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Example of savings with Carbon Zero
 Consider a ZR132 kW compressor and an energy recovery of 135 kW
 Heat equivalent per second = 135 kJ/s
 When using heating oil (HO)
 Calorific value = 41,200 kJ/l
 Boiler efficiency = 70% without recovery and 90% with recovery
 Heat generated per hour = 135 kJ/s x 3600
 Fuel saved = 135 x 3600 / (41,200 x 0.9) = 13 l/h = 3.4 gal/h
 Cost of fuel = 0.5€/l x 13 l/h = 6.50 €/h = 8 $/h
 Yearly savings = 6.5€ x 8000 h/y = 52,000
€ per year = $ 64,000 per year
* Calculation based on full load running for 8000 hours – full potential
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Carbon Zero ZR range
10.4 bar(e)
151 psig
4 bar(e)
58 psig
ZR 55 – ZR 750
ZR 75 VSD – ZR 700 VSD
270 m³/h
159 cfm
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7,470 m³/h
4,387 cfm
Conclusions: Energy Efficiency in CAS
Atlas Copco approach
 Reducing air leaks
– Ultrasonic leak detection
 Overall system design
– System audits and simulation
– Optimal compression technologies
– Control and ancillary systems
 Use of adjustable speed drives (ASD)
– Variable Speed Drives
 Recovery of waste heat
– Carbon Zero compressors recover up to 100%
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Committed to
sustainable productivity.
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