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“Industrial Energy Efficiency Down
Under”
New Zealand and Australian Case Studies
Dr James Neale & Hamish Wolstencroft
Energy Research Group
Industrial Energy Efficiency Division
The University of Waikato
Hamilton
New Zealand
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Research into improving Industrial Energy EfficiencyCompressed Air
Steam
Utility Loop Optimisation
Heat Recovery and Heat Integration
Pinch Analysis
Industrial Fluid Flow Optimisation
Renewable Energy Solutions
Distributed GenerationEnergy Audit Methodology Development.
Energy Research Group Overview
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Energy Research Group Overview
• Numerical ModellingComputational Fluid Dynamics Modelling
Proprietary Software Development
• Economic ModellingCapital Project Assessment
Energy Future Scenario Modelling
• Experimental Investigation & Analysis
Laboratory ScalePlant Scale
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Presentation Overview - Background
The Energy Landscape Down Under New Zealand
Australia
Compressed Air System energy SavingsOpportunitiesSystem Audits
Leak Management
Case Studies Air leak management
The Social or Human Dimension
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Presentation Overview – The good Stuff
Measuring a leak
Volumetric flow
Actual/Standard flow
Understanding leak types
Shape Size
Pressure Effects
Sound and Ultrasound Generation
Loss rate
Case Studies Revised Leak Guess-Timator
Software Tools for streamlined survey and reporting
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New Zealand Energy Landscape
NZ is entering an energy crisis
Lack of infrastructure investment
Cheap gas coming to an end
New generation costed at $2500 / kW by the ElectricityCommission. Cost to save electricity starts at $0 andgoes up.
Government committed to 90 % Renewable Electricity
Process Heat – almost left out of revised energystrategy
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New Zealand Energy Landscape – Greenhouse Gas
Emissions (2005 – Dry year)
Agriculture 48.5 %
Electricity 25 %
Transport 18.4 %
Industrial Processes 5.6 % Waste 2.4 %
Solvents 0.1 %
Notes• 66 % of Electricity is from Hydro
• 24.6 % increase in total 1990 emission levels
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NZ Energy Strategy
Energy Efficiency
Active energy efficiency programme (EECA)
Subsidised energy audits
Solar Hot Water SubsidiesCFL Light Bulb Subsidies
Industrial Programmes
Compressed Air Best practice programmes
Energy Efficient Motor SubsidiesOther work in progress
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Australian Energy Landscape
Energy
Large distance to market (gas)
High reliance on coal fired electricity
Reduced water storage and hydro electricity
Industrial process emissions up 16 %
Reliance on imported oil
Transport emissions up 29.9 %
Legislation introduced to mandate energy efficiencyprograms for industry - EEO
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Australian Energy Landscape – Greenhouse Gas
Emissions (2005 – Dry year)
Energy 55.6 %
Agriculture 15.7 %
Transport 14.4 %
Industrial Processes 5.3 % Waste 3.0 %
Land Use 6.0 %
Notes• 73.9 % reduction in land use emission levels
• 2.2 % increase in total 1990 emission levels
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Energy Savings in Compressed Air Systems
Compressed air is a unique utility for most plants since it is one of thefew where the plant has complete control over the production,distribution and use of the utility
80% of the electrical energy used by a compressor is converted to heat
No two air systems are alike and no two plants use air the same way. Itis important to take plant operations and requirements intoconsideration when analysing a system or changing to the system.
Compressed air is one of the most expensive sources of energy in aplant.
The overall efficiency of a typical compressed air system can be as lowas 10-15%
Opportunities to redistribute assets for optimum system efficiency
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Why Compressed Air
Increased Energy Costs
Climate Change and CO2 Emissions
10 to 40 % of Industrial Electricity Usage
20 to 30 % Cost Savings Commonly Found
Some cases of over 50 % savings
The Forgotten Utility
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Energy Assessment or System Audit?
Energy Assessment/Audit
Supply orientated
Limited ability to fully identify potential savings
A good start, but ….
System Audit
Focus on end use
Demand, Distribution and Supply orientated
Maximum Energy and Cost savingsCosts a little more to make 2 to 3 times the savings!
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Potential Demand Side Savings
Air Leaks → 10 to 50 % (Ave)
Artificial Demand → 5 to 50 % (Ave)
Peak Load Reduction → 10 to 20 % (Peak)
System Pressure Reduction → 4.5 to 9 % (Ave)
Energy SavingsCO2 Emission Reductions
Maintenance Savings
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Long Range Leak
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Man Made Leaks
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Man Made Leaks
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Leak by Design!
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Potential Supply Side Savings
True Demand Characterization – Must Come First
Compressor Run Order and Control
Minimise Unloaded Running Hours
Compressor SizingCompressor Technology Selection
Driers & Filters
Maintenance Savings
Total Savings of 10 to 30 %
Energy Savings
CO2 Emission Reductions
Maintenance Savings
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Savings Summary
Demand Side Savings typically 2 to 3 times the Supply SideSavings
Supply Side should only be optimised after the demand sideis under control!
Australian Model
Legislate change for large energy users
Limited government funding/assistance
New Zealand Model
Government funding conditional on demand side KPI’s
Demand Savings can be made that then can be re-invested insupply side improvements
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Initial Savings Estimate
Typical saving of 20 to 30 %
As high as 40 to 50+ %
Could be as low as
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What Is Measured
•Power Consumption (Power v Current)
•Pressure (gauge v absolute)
•Dew Point – Water Content
•Compressed Air Flow Rate (Supply/Demand)
Assumed flow (name plate)
Inline measurement – insertion options
Ultrasonic non-obtrusive measurement
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System Audit Report Contents
• Introduction
• Audit Methodology
• Compressed Air Demand Characterisation and Optimisation
• Compressed Air Distribution Summary
• Current Compressed Air Supply Summary
• Potential Compressed Air Supply Solutions
• Risk Assessment
• Potential Cost Savings Summary• Recommendations and Conclusions
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NZ Food Processing Examples
Leak Management
20 to 50 % savings
A single internal leak in a dust collector = 20%
Identification of critical areas for high spec fittings
Targeted maintenance
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NZ Food Processing Examples
•Artificial Demand Reduction
Cooling of bearings
Tank agitation
Air lances
Vacuum generators
Pneumatic conveying of powders
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NZ Food Processing Examples
•Peak Demand Balancing
Bag house pulsing
Automated powder packing
Purging product feed lines
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Bag House Air Demand
0
50
100
150
200
250
300
350
2/02/2007 12:00 2/02/2007 12:18 2/02/2007 12:36 2/02/2007 12:54
Time
A i r f l o w
R a
t e ( N
m 3 / h r )
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Bag House Air Demand
0
50
100
150
200
250
300
350
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Time (%)
A i i r f
l o w
R a
t e ( N m
3 / h r )
Inadequate Local Storage
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Artificial Air Demand
0
500
1000
1500
2000
2500
3000
1/02/2007 12:00 1/02/2007 15:00 1/02/2007 18:00 1/02/2007 21:00 2/02/2007 0:00
A i r D e m a n d ( N m
3 / h r )
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Artificial Air Demand
0
500
1000
1500
2000
2500
3000
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Time (%)
A i r D e a m n
d ( N m
3 / h r )
Artificial Peak
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Total Air Demand
0
500
1000
1500
2000
2500
3000
3500
4000
4500
2/02/2007 12:00 3/02/2007 0:00 3/02/2007 12:00 4/02/2007 0:00 4/02/2007 12:00 5/02/2007 0:00
T o t a l P l a n t D e a m n
d ( N m
3 / h r )
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Total Air Demand
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Time (%)
T o t a l P l a n t D e m a n
d ( N m
3 / h r )
Demand Peak = Over Capitalisation
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Leak Detection or Leak Management
•Leak Detection
•Leak Characterisation
•Fix Leaks →Lock in Energy Savings
•Data Management
Cost Benefit Analysis
Establish Rate of Reoccurrence
Verify Improvements
Proactive & Targeted Maintenance
Site and Corporate Reporting and Benchmarking
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Maintenance is more than plant reliability
Maintenance can have an IRR Air leak survey cost $6,000, saved $80,000 and shutdown
a 250 kW air compressor. Improved rate means less energy per tonne of product
Vacuum leaks fixed means happy operators
As maintenance professionals which budget do you getmeasured on?
Change in KPI’s for management to reflect new focusManagement Buy in to leak management programme
Maintenance Example
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Barriers To Success
•No Savings Until Leaks Are Fixed
•Technical Challenges
Scheduling of repair work
Maintenance priorities
•Social (Human) Challenges
Education
Ownership
Workload
Incentives
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Barriers To Success•No Savings Until Leaks Are Fixed
•Technical Challenges
Scheduling of repair work
Maintenance priorities
•Social (Human) Challenges
Education
Ownership/Attitude and Culture
Workload Management
•Fiscal ChallengesCost of leak survey and repair work
Risk to achieving projected savings
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The Solution
•Tailored Leak Management Program
•Certified Personnel : SNT-TC-1A
•Robust Data Management
Electronic Reporting
Historical Trending
Plant by Plant and Site by Site Comparisons
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The Solution
•Ultrasonic Leak Detection
Can identify leaks while plant is running
Non-intrusive
Sound level correlates to leak rate (dB)
•Customised Thresholds
Start with relatively high threshold
Lower threshold as plant improves
Allows a manageable work load
Can go straight to low threshold if desired, but …
80-20 rule applies
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Compressed Air Summary:
Significant energy savings can be made through correctauditing of compressed air systems
Demand Side optimisation must be addressed first, then the
supply side of the system may be optimised
The compressed air system must be analysed as a whole notindividual elements.
Human/Social barriers to change must be addressed if savings are to be locked in long term.
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Let’s Recap - Why do an Airline Leak Detection
Survey?
Compressed air is an expensive utility.
A simple programme of inspection and repair can reduce costs.
Thousands of dollars are wasted because of air leaks.
Why Use Ultrasonic Leak Detection?
Can be done while the plant is running.
Picks up leaks not audible to the ear.
Simple and accurate.
Implementation of a comprehensive air leak management planhas led to demand savings of over 30 %.
Optimum scheduling of air leak surveys with targeted approachto critical areas
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Air Leaks – All Different Shapes and Sizes
Let’s consider an air leak in a lot more detail
How to quantify the loss Loss rate
Cost (daily, monthly, yearly) Types of leaks
Why is pressure so important?
Examples – loss form an orifice Theory
Practice
Software tools to simplify an air leak survey
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Measuring a leak
Actual/Standard Flow
Turbulence in the flow generates Airborne Ultrasound.
Pressure
Leak
VacuumLeak
Volumetric Flow
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Pressure Effects – Why is pressure so important?
Any leak to atmosphere will expand from the internalpressure down to zero gauge pressure (atmosphericpressure).
Increasing the pressure increases the actual flow ratefor the same volumetric flow rate.
If the pressure in the leaking line exceeds a criticalpressure the volumetric flow through the leak orifice
will be choked (maximised).
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Pressure Effects – Why is pressure so important?
01
2
3
4
5
67
8
9
10
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
Exit Pressure (Bar)
V o l u m e t r i c F l o w
R a t e
( m 3 / h )
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Pressure Effects – Why is pressure so important?
0
5
10
15
20
25
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Pressure (Bar)
N o r m a l F l o w R a t e
( N m
3 / h )
4mm tube (Nm3/h)
6mm tube (Nm3/h)
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Leak Path Length Effects
Round Orifice Leak Rates
Internal Diameter
External Diameter
Leak Path Length Effects Lowers effective leak exit pressure
Gradual expansion of compressed air
Reduces loss rate
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Leak Path Length Effects – 4mm diameter orifice
0
5
10
15
20
25
30
35
40
45
50
0 1 2 3 4 5 6 7 8 9 10
Length (m)
F l o w
R a
t e ( N m
3 / h )
6 Bar
5 Bar
4 Bar
3 Bar
2 Bar
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Leak Path Length Effects – Extending the length
0
5
10
15
20
25
30
35
1 10 100
Length (m)
F l o w
R a t e ( N m
3 / h )
6 Bar
5 Bar
4 Bar
3 Bar 2 Bar
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Angle Of Approach
• Angle Effects The dB Reading Symmetry
Exit Path
Source Location• Variation In dB Increases With Increasing Pressure
Peaks @ 30-40 ° from central axis
Minimum @ 0 °
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Angle Of Approach – 100 mm From Leak
0
10
20
30
40
50
6070
80
90
100
110
120
0 10 20 30 40 50 60 70 80 90
Angle
d B
6 bar
5.5 bar
5 bar
4.5 bar
4 bar
3.5 bar 3 bar
2.5 bar
2 bar
1.5 bar
1 bar
0.8 bar
0.6 bar
0.4 bar
0.2 bar
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Angle Of Approach – 150 mm From Leak
010
20
30
40
50
60
70
80
90
100
110120
0 10 20 30 40 50 60 70 80 90
Angle
d B
6 bar
5.5 bar
5 bar
4.5 bar
4 bar
3 bar
2.5 bar
2 bar
1.5 bar
1 bar
0.8 bar
0.6 bar
0.4 bar
0.2 bar
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Angle Of Approach – 300 mm From Leak
010
20
30
40
50
6070
80
90
100
110
120
0 10 20 30 40 50 60 70 80 90
Angle
d B
6 bar
5.5 bar
5 bar
4.5 bar
4 bar
3.5 bar
3 bar
2.5 bar
2 bar
1.5 bar
1 bar
0.8 bar
0.6 bar
0.4 bar
0.2 bar
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Leak Types and Shapes
Many leak types exist yet all can be Simplified down toa few simple geometric shapes:Hole
Slit/crack
Slot
Tube
Loss rates and ultrasound levels depend on both thesize and shape of the leak orifice.
Larger orifice will have a lower ultrasound level for thesame loss rate (for a smaller orifice).
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Leak Types and Shapes - Comparisons
0
10
20
30
40
50
60
70
80
90
100
0 15 30 45 60 75 90
Angle ( deg)
D e c
i b e
l R e a
d i n g
( d B )
4mm Open End - 30.17m3/hr 15mm slit vert - 28.51m3/hr
10mm Slit vert - 21.79m3/hr 2.5mm Pinprick - 14.64m3/hr
2.5mm Open End - 10.06m3/hr 2mm Pinprick - 9.66m3/hr
5mm Slit vert - 5.18m3/hr 1.5mm Pinprick - 2.71m3/hr
1mm Pinprick - 1.54m3/hr
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Leak Types and Shapes - Slits
0
10
20
30
40
50
60
70
80
90
100
0 15 30 45 60 75 90
Angle ( deg)
D e c
i b e
l R e a
d i n
g ( d B )
15mm slit vert - 28.51m3/hr
10mm Slit vert - 21.79m3/hr
5mm Slit vert - 5.18m3/hr
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Leak Types and Shapes – 6 Bar (g) Slit
010
20
30
40
5060
70
80
90
100
0 15 30 45 60 75 90
Angle (deg)
D e c
i b e
l R e a
d i n g
( d B )
15mm slit @ 1m - 27.49m3/hr
10mm slit @ 1m - 20.43m3/hr
5mm slit @ 1m - 2.22m3/hr
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Leak Types and Shapes – 3 Bar (g) Slit
010
20
30
40
50
60
70
80
90
0 15 30 45 60 75 90
Angle (deg)
D e c i b e l R e a d i n
g ( d B )
15mm slit @ 1m - 12.31m3/hr
10mm slit @ 1m - 7.95m3/hr
5mm slit @ 1m - 0.81m3/hr
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Leak Types and Shapes – 6 Bar (g) Pinprick
010
20
30
40
50
60
70
80
90
100
0 15 30 45 60 75 90
Angle (deg)
D e c i b e l R e a d i n g ( d B )
2.5mm Pinprick 1m - 14.64m3/hr
2mm Pinprick 1m - 9.66m3/hr
1.5mm Pinprick 1m - 2.71m3/hr
1mm Pinprick 1m - 1.54m3/hr
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Leak Types and Shapes – 3 Bar (g) Pinprick
0
10
20
30
40
50
60
70
80
90
0 15 30 45 60 75 90
Angle (deg)
D e c i b e l R e a d i n g ( d B )
2.5mm Pinprick @ 1m - 8.30m3/hr
2mm Pinprick @ 1m - 5.81m3/hr
1.5mm Pinprick @ 1m -1.33m3/hr
1mm Pinprick @ 1m - 0.78m3/hr
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The Leak Management Process
Leak Detection
Tag Leak and Record Data
Input to Leak Database
Data Analysis and Report Generation
Investment Decision (Fix Leaks)
Work load Management
Repeat Survey
Historical Data Used to Determine Survey Frequency
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The Leak Management Process – Software Tools
PDA for in field data storage
Integrated Leak Database
Standardised Report Formats
Historical ReportingCorporate Reporting
Future Web Based Platform
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The Leak Management Process – PDA
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The Leak Management Process – Conclusions
Work Load is minimised In Field Data Recording
Data Analysis And Report Preparation
Information is only of value if: Accessed Easily Presented In Meaningful Formats
Extract Historical Data For Real Practical Benefit
PDA enables complex variation in leak rates for
different leak types to be easily incorporated with noadditional work load
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Acknowledgements
New Zealand Foundation for Research Science &Technology
New Zealand Energy Efficiency Conservation Authority
(EECA) Further information: [email protected]