This project has been assisted by the New South Wales Government through its Energy Efficiency...

This project has been assisted by the New South Wales Government through its Energy Efficiency Training Program

Prepared by

Energy Efficiency through Product & Process

Design

Prepared by Plastics Industry Manufacturers of Australia (PIMA) in partnership with Australian Management Academy (AMA);

executed in collaboration with EcoProducts

Copyright and disclaimer

The Office of Environment and Heritage and the State of NSW are pleased to allow this material to be used, reproduced and adapted, provided the meaning is unchanged and its source, publisher and authorship are acknowledged.

The Office of Environment and Heritage has made all reasonable effort to ensure that the contents of this document are factual and free of error. However, the State of NSW and the Office of Environment and Heritage shall not be liable for any damage which may occur in relation to any person taking action or not on the basis of this document.

Office of Environment and Heritage, Department of Premier and Cabinet

Phone: (02) 9995 5000 (switchboard)

Email: [email protected]

Website: www.environment.nsw.gov.au

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Energy Efficiency through Product & Process

Design

Module 8 – Energy Efficient Manufacturing Process Design

© Australian Management Academy and Eco Products Agency

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Key Points

1. Saving energy through process design

2. Designing energy efficient processes

3. Energy efficient process equipment

4© Australian Management Academy and Eco Products Agency

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

$10028%

$72

Process Optimization 15% savingProcess Design 15% savingTOTAL (cumulative) 28% saving

ProductDesign Process

Design ProcessOptimization

6© Australian Management Academy and Eco

Products Agency

Designing Energy Efficient Processes

1. Understand where energy is being used

2. Measure energy use

3. Analyze energy use

4. Compare to benchmarks

5. Identify opportunities


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Designing Energy Efficient Processes

• 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?

8© Australian Management Academy and Eco Products

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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

• system efficiency = 60% x 95% x 35% = 20%

• primary energy use is 5 times applied energy9


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


Primary Process


Primary Processes

• Use the right size process– Minimum size machine for the required output

• Clamp tonnage• Injection unit size• Extruder screw diameter• Dryer size

• Multi-cavity tooling can increase energy efficiency


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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



• Typical energy savings of 30% - 60%– 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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Application exampleEnergy 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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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


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


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


Electric Motors


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


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


Automation

• Process automation can save energy– Faster cycling– Better reproducibility– Less downtime– Process integration

Automated clip insert loading


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


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


Dryers

• Eliminate or minimize energy use for drying

• Use dry material from sealed bags• Use correctly sized, energy efficient driers• Do not over-dry. Minimize time & temperature


Granulators

• Are they needed? – Hot runners can eliminate

• Design granulators correctly– 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


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


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


Cogeneration

• On-site generation of electricity plus heat and chilled water (tri-generation)


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


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 plant386 kW electrical power290 kW chilled water230 kW hot waterEst. 80% thermal efficiency


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


Agency

This project has been assisted by the New South Wales Government through its Energy Efficiency...

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