Transcript Energy Efficiency through Product & Process Design

This project has been assisted by
the New South Wales Government
through its Energy Efficiency Training Program
Energy Efficiency
through Product & Process
Design
Prepared by
Prepared by Plastics Industry Manufacturers of Australia (PIMA)
in partnership with Australian Management Academy (AMA);
executed in collaboration with EcoProducts
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Office of Environment and Heritage, Department of Premier and Cabinet
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Energy Efficiency
through Product & Process
Design
Module 8 – Energy Efficient
Manufacturing Process Design
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Agency
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Key Points
1. Saving energy through process design
2. Designing energy efficient processes
3. Energy efficient process equipment
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Saving Energy through
Process Design
Energy savings can be obtained by process
design for new or existing products
• Investment in energy efficient equipment
• Improvement of existing equipment
• Automation
Typically provides 15% energy saving
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Energy Saving through
Process Design
Energy Cost
$100
28%
$72
Product
Design
Process
Design
Process
Optimization
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Products Agency
Process Optimization 15%
saving
Process Design
15%
saving
TOTAL (cumulative)
28% saving
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Designing Energy Efficient
Processes
1.
2.
3.
4.
5.
Understand where energy is being used
Measure energy use
Analyze energy use
Compare to benchmarks
Identify opportunities
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Designing Energy Efficient
Processes
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Where will energy being used?
What will the energy be used for?
How much energy will be used?
Can it be used more efficiently?
Could energy be supplied more efficiently?
Where is energy being wasted?
Can waste energy be reduced?
Can waste energy be recovered?
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System Design
• Looking at the whole energy use of a plant
back to the primary energy sources to identify
environmental impact
energy
efficiency
pump motor
60%
transmission & distribution of
electricity
95%
generation of electricity
35%
• system efficiency = 60% x 95% x 35% = 20%
• primary energy use is 5 times applied energy
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Agency
Primary Processes
Pick the most energy efficient primary process
option:
– injection
– extrusion + cutting + assembly
– sheet extrusion + thermoforming + trimming
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Primary Processes
Integrate processes to avoid extra heating/cooling
cycles:
– Direct sheet extrusion/thermoforming
– Direct compounding/injection
– Requires high volumes to justify high capital
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Example
Peguform GmbH
– Automotive door module
– Compounding + Injection moulder with integrated
foamed in place PU gasket
– 300 MWh/year energy saving
– Additional savings from logistics simplification
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Primary Process
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Primary Processes
• Use the right size process
– Minimum size machine for the required output
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Clamp tonnage
Injection unit size
Extruder screw diameter
Dryer size
• Multi-cavity tooling can increase energy
efficiency
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Agency
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Primary Processes
But it may be more efficient to run a larger machine slower
than a smaller machine ‘flat-out’
30% GF PA-6 compounded at 2,100 kg/h
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Electric Injection Moulders
• Electric servo injection moulding machines use much
less energy than hydraulic machines
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Electric Injection Moulders
• Typical energy savings of 30% - 60%
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No hydraulic pump operating continuously
No cooling for hydraulic system
Simultaneous movements allow faster cycles
High accuracy may reduce rejects
Lower peak demand
• Capital cost is higher
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Electric Injection Moulders
Application example
Energy
Saving
Medical product (inhaler)
58%
Medical component product (in
polystyrene)
60%
Automotive connectors
33% – 66%
Cap (stack tool)
28% – 64%
Flower pot
40%
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© Australian Management Academy and Eco Products
Agency
Example
Gerresheimer AG Medical Plastics Systems
Division, Pfreimd, Germany
– Replaced 15 hydraulic injection moulding machines
with all-electric machines.
– Saving 900 MWh of electricity per year.
– Co-generation plant installed to save 28% of primary
energy consumption.
– Heat recovery systems installed on compressors at
several plants
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Agency
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Other Developments
• Integrated energy monitoring
– E.g. Krauss Maffei Energy Analysis Tool
instantaneously logs machine energy consumption
• Energy regeneration from braking force
– E.g. Wittmann Battenfeld EcoPower system uses
braking energy for barrel heating
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Secondary Processes
• Integrate primary and secondary processes
– Insert moulding vs moulding + assembly
– Low pressure moulding with surface materials
– In-Mould Decoration
• Avoid packing, moving, storing, unpacking
• Also requires high volumes to justify high capital
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Secondary Processes
• Painting & coating processes
– Drying ovens and tunnels can be high energy users
– Gas may be more efficient than electric heating
– Infra-red or halogen lamps with tailored emission
spectrum can be more efficient than convection
heating
– 'Effects' materials
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Electric Motors
• Electric motors are most efficient when operated
near rated load
– Don’t over-design with oversized motors
• High-efficiency motors 2–3% more efficient
– Always worth the extra cost for energy savings
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Electric Motors
Rating
30 kW
55 kW
110 kW
Standard motor
89.5%
91.5%
92.5%
High Efficiency Motor
93.0%
93.5%
94.5%
Annual hours operation
6000
6000
6000
Energy cost per kWh
$0.14
$0.14
$0.14
Additional cost for HEM
$424
$960
$1,654
Annual savings
$882
$924
$1,848
0.48 yrs
1.04 yrs
0.90 yrs
Simple payback (years)
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Agency
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Electric Motors
• AC motors are more efficient than DC motors
• AC motors run at a speed set by the electricity
supply frequency (50 Hz)
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Variable Speed Drives
• Can be used on most motor driven equipment
• Allows speed of AC motors to be varied
• Variable Speed Drives (VSD) can give 50%
energy savings on motors drives
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Variable Speed Drives
• Hydraulic pumps on injection moulding
machines run continuously and have excess
capacity to meet peak demand
• Pump still draws 50% - 75% of rated power
under low load
• VSDs can reduce the pump speed when
demand is low
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Automation
• Process automation can save energy
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Faster cycling
Better reproducibility
Less downtime
Process integration
Automated clip insert loading
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Example
AGRU Kunstofftechnik GmbH
– Pipe extrusion plant with up to 15 diameter
changes per week
– Installed Krauss Maffei
QuickSwitch System
– 100 MWh/year electricity
saving due to reduced
change-over time
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Agency
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Dryers
• Drying is a major energy consumer
– 30% of energy use in PET processing
• New technologies use less energy
– Moretto Flowmatik
• Zeolite drying uses less energy for regeneration
• Controls minimize airflow
– Maguire Low Pressure Dryer
• Vacuum assists moisture removal
• Claim 70-80% energy saving, 6 x faster
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Dryers
• Eliminate or minimize energy use for drying
Need drying
May not need drying
Polyamide (Nylon)
Polypropylene
Acrylic
Polyethylene
Polycarbonate
PVC
• Use dry material from sealed bags
• Use correctly sized, energy efficient driers
• Do not over-dry. Minimize time & temperature
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Granulators
• Are they needed?
– Hot runners can eliminate
• Design granulators correctly
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Use correctly sized equipment
Granulate sprues, runners & cut-offs immediately
Avoid off-line granulating
Avoid cooling, then re-drying and re-heating
Turn off granulators when not operating
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Compressors
• Compressed air is an expensive energy source
• Find an alternative
• Systems need correct design
– Compressor selection
– Reservoir size
– Distribution pipes
• Variable speed and variable displacement
compressors can provide good savings
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Cooling Systems
• Design cooling systems for energy efficiency
– Chillers can use a significant amount of process
energy
– Design cooling channels in tools properly to increase
thermal transfer and reduce pressure loss
– Very low tool temperatures may not speed up cycle
times for thick wall parts
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Cogeneration
• On-site generation of electricity plus heat and
chilled water (tri-generation)
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Cogeneration
• Widely used in Europe
– EU 20% target for 2010
– Up to 50% in Scandinavia
• Low penetration in Australia
– About 5% (1.5% in sugar industry)
– High capital and operating cost
– Higher electricity cost vs grid
– Need demand for heat energy
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Cogeneration
• But becoming more viable
– Plant costs and operating costs are reducing
– Gas cost vs rising electricity cost
– Absorption chillers provide chilled water
efficiently
– Energy companies will supply and operate
EPA Melbourne trigen plant
386 kW electrical power
290 kW chilled water
230 kW hot water
Est. 80% thermal efficiency
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Agency
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Summary
• There are significant opportunities for energy
saving through process design
• Process design should use a systematic
approach to achieve energy efficiency
• Many new technologies offer energy savings
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Agency
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