ti-energy worksheets plastics) - tangram

8/6/2019 TI-Energy Worksheets Plastics) - Tangram

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Energy efficiency in plasticsprocessing

Practical worksheets for industry

Energy worksheets 1 - 12

TANGRAM

TECHNOLOGY


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Energy e f f ic ienc y in p last ic s process ing

Typical Site Energy Usage over Time

2 4 6 8 10 12 14 16 18 20 22 0

Unproductiveoperation

Productive operation

Time

Base loadUnproductiveoperation

EnergyUse(kWhr)

locate areas for monitoring andimprovement.

When are you using energy?

The time at which you are using energyis important and demand plotted

versus time will give invaluableinformation on how to reduce theenergy costs (see below). Data forsuch plots should be available fromyour supply company. Look for unusualpeak variations from day to day andenergy use when there is noproduction. A demand graph also helpsyou to find the base load. This is theload used for heating, lighting,compressors and pumps when youhave no production at all.Another way to find the base load is to

record the meter readings (in kWh) andproduction volumes (in kg) at the endof each shift. Plot the amount ofpolymer processed against the energyconsumption. From the graph, theenergy use at zero production gives anidea of the base load. Reducing thebase load is a sure way to makesavings.

Why are you using energy?

Ideally energy should be used only toproduce good product and the mostimportant energy benchmark is theenergy used to process good product(in kWh/kg). This is called the specificenergy consumption (SEC) and can befound from the slope of the graphproduced to find the base load. It canbe compared to the industry averagesto provide targets for energy reduction.Is energy being used to keep machinesidling when they could be turned off?Are heaters running that are not beingused? Are compressors running just topump air out of leaks? Finding out whyyou are using energy will reveal a widerange of possible steps for reducing

energy use.How much energy are you using?

Electricity charges are based on a

combination of factors (see right) andan initial survey will reveal areas forpotential savings, sometimes actionsas simple as changing the tariff canreduce costs at no cost! Peak demand

lopping can be very effective to reduceshort peaks in the maximum demand.

Get free advice and help

Energy management will save moneyand make you more competitive. Startyour energy management programmetoday and reap the benefits ofimproved profits by cost effectiveinvestment and management.Action Energy provides free resourcesfor energy management and costreduction in plastics processing. Aninitial handbook Energy in Plastics

Processing - a practicalguide (GPG292) gives essentialinformation on how to start reducingyour energy costs and signpostsfurther free information.Get the information, save the moneyand become more competitive!

Reducing energy costs - thefirst steps

The Climate Change Levy willincrease the cost of electricity by0.43p/kWh and the base energygeneration costs are rising throughoutthe world. Energy costs are alwayssomebody elses problem and theplastics processing industry generallyregards the energy as an overheadand as a fixed cost. This is untrue andenergy is both a variable and acontrollable cost. Most processorscould easily reduce energy costs(without large investments) andincrease profits through simple goodenergy management practice. Thisseries aims to show you how to reduce

energy usage and increase yourprofits.

The vital questions

Before you can start to reduce yourenergy costs you need to understandwhere, when why and how muchenergy you are using. This information

provides the benchmarks andsignposts for improvement.

Where are you using energy?

The main electrical energy users aremotors and drives, heaters, coolingsystems and lighting systems. A simplesite energy distribution map will showwhere energy is being used. If you areusing a single meter it may be costeffective to use sub-meters to getfurther information on the areas of highenergy use. Sub metering allows youto start to calculate the cost of energyfor each operation and to identify areas

of high energy usage - a key factor inreducing energy costs. A first step is toproduce an energy map of your site to

Energy is a variable and acontrollable cost

Key tips for reducing the cost ofelectricity

Maximum Power Requirement isthe maximum current a site can drawat the supply voltage. Reduce the

cost by:Staggering start-ups.

Matching the MPR to therequirements.

Getting the MPR right for newpremises to avoid costly charges.

Negotiating an annually based MDinstead of an MPR charge.Maximum Demand is the currentdrawn at the supply voltageaveraged over half an hour. Reducethe cost by:

Staggering start-ups.

Giving machinery time to stabilisebefore starting up new processes.Power Factor is a measure of thephase shift created by machinery.Lightly loaded machinery tends tohave a high phase shift, and a lowpower factor. Improve the powerfactor by running electric motorsefficiently to get power factors closeto 1.Load Factor is a measure of thehours per day that the user drawsfrom the supply. Reduce the cost by:

Running for greater than a singleshift.

Carrying out some operationsoutside the main shift pattern e.g.regrinding.


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Polymer Transport Heat Form

CoolTransport Post-Process

Energy Energy Energy

EnergyEnergyEnergy

Product

Services and buildings energy needs

The questions to ask (and answer)

Which areas have the largestelectrical load? (look for the largestmachines, they will most likely alsohave the largest motors and create the

largest load, when they are used).Is the thermal insulation, if present, onall the machines in good condition? Ifthere is no insulation then why not?

Look for signs of machines that arenot in production but have motors orancillary equipment running (e.g.conveyors, pumps, granulators, fans,machine heaters).

Are there any good reasons whymachines need to be kept idling to beready for the next production run?

Which motors are left running when

not doing productive work?Why are the motors the size they areand would a smaller motor be moreefficient?

Which cooling water pumps (andchillers) and vacuum pumps are stillrunning?

Is the airflow from fans being throttledback with dampers and could variablespeed drives be used instead?

Look for areas of energy use whereno productive work is being carried outand yet machines are running and

using energy.Look for water, air or steam leaks.

Where can you hear steam andcompressed air leaks? The hissingnoise you hear from leaks is costingreal money. If there is no productionbeing carried out then why is thecompressed air system still running?

Is compressed air being used forexpensive applications where othercheaper methods can be used? e.g.cleaning or drying.

Does the compressed air pressureneed to be so high, or the vacuum solow?

The rewards

Energy efficiency measures canimprove your profits significantly forminimum effort and costs. For aplastics company with a turnover of10 million per year and a net profit of10% then the profit will be 1 million.The average electricity bill will beapproximately 200,000 (between 1and 3% of turnover). Simple no-cost orlow-cost energy reduction practicescan reduce this by a minimum of 10%(and up to 20%) and increase profits byat least 2%. This is the equivalent ofadding sales of 200,000 to turnoverand is a worthwhile investment by anystandards.

The initial site energy survey

The objective of an energy survey is togain an overview of the general siteenergy use. It is a walk around the sitewith an energy managers hat on. Thiswill identify some rapid no-cost or low-cost improvements that can be madeto save money.The survey should be carried out as

soon as possible - if energy is beingwasted now, it is costing money now.The diagram shows the main areas ofenergy use in plastics processing. Usethis as a guide during your walk-aroundto look for areas of high orunnecessary energy usage.

How do you do a site survey?Take an unannounced walk aroundthe site at around mid-shift. If there isno night shift it can also be profitable totake a walk around the factory whenthere is no production being carried

out.

Low cost energy efficiencymeasures can improve profits

significantly

Is the lighting dirty, broken?

What are the good, simplemaintenance measures that can beadopted to reduce energy use?

Are accepted practices wasting

energy? Can they be modified at nocost at all?

Are there clear setting instructions forall machines and products and are theyimplemented when setting up?

Turning the survey into energysavings

A site energy survey is useless unlessaction is taken as a result of thefindings. Use the survey to estimatethe excess energy usage of the siteand arrange for an electrician tomeasure the factory electrical load andcalculate the costs involved. Use thesurvey to identify operating practicesthat cost money and need to bechanged. The results of the surveyshould be sent to the ManagingDirector and Production Director withfull recommendations and costs for

carrying them out.Raising energy awareness

The cost savings possible from energyefficiency will only be achieved if thereis a management commitment toactually carry out the work necessaryand save the money. This is bestensured by having an energy policythat is as much a part of the overallcompany operations as the qualitypolicy. The energy policy should ideallybe part of a broader companyenvironmental policy and, at the veryleast, should be formally adopted withtop-level management commitment.The policy should be the responsibilityof a designated Energy Manager whohas clear responsibility for energymatters. There needs to be regularformal and informal communicationwith major users who are heldaccountable for their energy usagewhich should be monitored andtargeted. The quantified savings fromthe implemented energy policy shouldbe promoted within the company andused to create a favourable climate for

investment treatment of other energysaving programmes.Energy efficiency is a competitiveadvantage in any market and an initialsite survey is the start of gaining theadvantage for your company.

Energy uses in plastics processing

An initial site survey is a keystarting point for energy saving


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PlasticsProcessing

Administrationoffices

Utilities

Water Compressed air Heat Light

Pumping Conditioning

Processing

ProcessingA

ProcessingB

Materials

Re-chip

Reprocessing Handling

Re-pellet

(www.eca.gov.uk) to identify energyefficient plant and machinery fortechnologies such as motors,compressed air, refrigeration, boilersand lighting.

Tip: Ask suppliers for proof of theenergy efficiency of their products andcheck that it is applicable to the project.

Tip: Be prepared to pay slightly morein initial purchase cost for energyefficiency.

Tip: Electric motors are often hiddenand use large amounts of energy.Specify energy efficient motors for allpurchases.

Tip: Set up a simple 'motormanagement policy' so that everybodyknows the rules for purchasing,

replacing and rewinding of electricmotors for energy efficiency.

Tip: Look for projects where the rulescan be changed to the company'sadvantage and make energy savingautomatic.

Typical projects

Plastics processors can save money inall areas of their operations byinvesting in energy efficiency. Thediagram below shows where energy isused in plastics processing.Opportunities for energy savings

through investment are everywhere.Technology makes it possible to re-equip a factory for lower operatingcosts.Potential areas for investment toreduce energy use and costs include:

All-electric injection mouldingmachines

Cooling water treatment

Capital equipment selection:changing the rules

Many people think that energyefficiency is simply about turning outlights and turning down the heating.Though partially true, it is not the wholestory. Energy efficiency is also aboutusing cost-effective technology topermanently reduce a company'senergy consumption. For example,changing the behaviour of people toturn out lights requires them to bemotivated and constantly encouraged.Changing the light switch for a passiveinfrared (PIR) detector is quick, lowcost and effectively permanent. Inmany cases, it is easier to change therules than to change the people.

This is even more critical whenselecting capital equipment for plastics

processing. It is easier and cheaper tospecify and purchase energy efficientequipment at the start than to pay

continuously for the energy it uses andto then try to upgrade the equipmentlater. Purchasing energy efficientcapital equipment is the simplest andeasiest way to permanently improve acompany's overall energy efficiencyand reduce its energy costs.The cost of the energy used during itslifetime will be more than the initial costof virtually any capital equipment. It willbe even more for machines that are notenergy efficient. Energy efficientmachines save money in the longterm - an important factor when

customers are beginning to expectprice decreases through the lifetime ofa product.As with any capital equipment, theinitial purchase cost should notdominate the decision-making process.The 'whole life' cost of the equipment(initial cost + operating costs) is theimportant cost for any plasticsprocessor who wants to continueoperating in the long term.

Tip: Make an 'energy efficiencyassessment' part of the capital

expenditure approval process. If thereis no assessment of energy use as partof the operational costs, then thecapital expenditure should not beapproved.

Tip: Use the Energy Technology List

Purchasing energy efficientcapital equipment will

permanently change the energyefficiency of a company

Polymer drying

Polymer transport and conveying

Lighting schemes and controls

Compressors and controls.These are all projects where currenttechnology has proven energy savingbenefits. Typical projects have

paybacks ranging from under 4 yearsand often as low as 9 months.

Opportunities for energy savings through investment are everywhere.Technology makes it possible to re-equip a factory for lower operating

costs.

The cost of energy used during

a machine's life will oftenexceed its initial purchase cost.Energy efficient machines andcontrols may cost more at thestart, but they cost less in the

long term.


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with no other effect. Starting multiplemachines at the same time willincrease the Maximum Demand andthe energy cost.

Tip: Fit a warning device to the MD

meter to sound when the loadapproaches the allowable limit.

Tip: Plan and control the start-upsequenceMachines use energy even whenidling, the amount varies with themachine to but can range from 52% upto 97.5% of the full mouldingconsumption. An idling machine is notfree.

Tip: Idle periods of between 20 to 45minutes may make it cheaper to switchoff and restart.

Tip: Are barrel heaters and coolingfans left on between runs?

Tip: Is cooling water circulatingthrough idle tooling?

Tip: Is compressed air supplied to idlemachines?All-electric machines are an energyefficient solution and can both reduceenergy use and make computer controleasier and more direct. Onconventional machines the hydraulicsystems provide peak power for a veryshort time and the hydraulic system isoverrated for most of the time.

Tip: The use of accumulators for rapidhydraulic energy release cansignificantly reduce the hydraulicsystem size.Heat transfer to the barrel is improvedby pre-seating the heating element tothe barrel and by using flexible metalbearing compounds.

Tip: Thermal efficiency can also beimproved by barrel insulation. This hasa rapid payback (generally under oneyear) and improves other areas suchas Health and Safety and fluctuations

due to air currents.Preventative maintenance such as de-aeration of the oil system andmaintenance of the controls will reduceenergy costs.

Tip: Monitor the energy use to identifydeterioration of the machine.

Tip: Increased maintenance can leadto significant energy savings.

Moulds

Product cooling time is generally morethan 50% of the cycle time. Efficientcooling can greatly reduce cycle times

and energy usage - a double benefit.Tip: Is cooling water at the maximumtemperature and minimum quality, howefficiently is it treated and distributed?

Tip: Air in the cooling system reducesthe cooling effectiveness. Degassed

Injection moulding

Over 90% of the energy costs ininjection moulding are accounted for byelectricity. This makes electricitypurchasing very important for mouldersand costs can be significantly reducedby good purchasing and operationalcontrols. Only 5 to 10% of the totalenergy used in the process is actuallyinput to the polymer, the other 90 to95% is used to operate the machineand large savings can be made.

Moulding machinesAs with most machines, the initial costof a moulder will be less than the costof energy used during its lifetime. Theenergy cost will be even more formachines that are not energy efficient.Although it may cost more initially,energy efficiency will save money inthe long term, a factor that is becomingmore important in markets wherecustomers expect decreasing pricesthrough the lifetime of a product.

Tip: Use whole life costing for newmachines and include energy costs.

Tip: Contact machinery suppliers forinformation on additional equipment toreduce energy consumption.

Tip: New generation machines oftenhave improved energy efficiency andcan reduce product costs by over 3%.Getting the right machine for the job isvital and the machine should be closelymatched to the product.

Tip: Using large machines for smallproducts is inherently wasteful. Are alljobs on the appropriate machines?

Tip: Total efficiency decreases as the

operating conditions move further awayfrom the design conditions.Electric motors account for 60% of theelectricity used in moulders and themoulding cycle causes intermittent,variable loads with Power Factorvalues in the region of 0.7. PFcorrection equipment can increase thePF to greater than 0.95 with a paybackof less than one year.

Tip: Improving the PF is cost effectiveand simple with excellent payback.

Tip: Motors are most efficient near the

design load. Oversized motors at partload are less efficient than smallmotors at full load. Check all motorsizes.Controlling the start-up sequence ofmachines can reduce energy costs

Good practice is inexpensiveand reduces all costs - not just

energy costs

and pressurised systems can reducecycle times and energy usage.Excessive tool change times will wasteenergy if the machine is idling. Rapidset up of tooling reduces energy and

improves overall factory effectiveness.Tip: Are tool changes planned intoproduction schedules? Are they quick?

Ancillaries and services

Ancillaries use energy in electricmotors and consumption of utilities. Forhighly automated production the totalancillary energy demand can becomparable to the machine energydemand. The main opportunities areminimising the demand for utilities.Motors are generally small and runintermittently and it is often not cost

effective to retrofit more efficientmotors or controls.

Tip: Specifying energy efficiencyduring design of handling andancillaries will give rapid payback onany additional costs involved.

Tip: Check that handling systems canbe set to operate on-demand only.

Tip: Match utilities to the demand.Granulation and scrap recovery useslarge amounts of energy and can willraise energy bills considerably.

Tip: Carry out granulation at night.Heat recovered from hydraulic systemsand chiller units through heatexchangers can be used to providespace heating for offices and otherareas with pay back times of 6 months.

Tip: Look for opportunities to recoverheat and reuse energy.

Management controls

Tweaking of machines by operatorscauses more lost time and energy thanalmost any other cause.

Tip: Optimising the machine settingsreduces the electrical energy needed.Get machines set right, record thesettings and do not change themunless absolutely necessary.

Tip: Use Statistical Process Control tocontrol machine settings andperformance.

The goal

Management is really at the heart ofenergy efficiency, without goodmanagement, neither energy efficiencynor any other change in operatingpractices will be effective. Energyefficient injection moulding is simplygood moulding practice. It is

inexpensive and reduces all costs notjust energy costs. Start working onenergy efficiency today and reduceyour costs to become a world classenergy efficient moulder.


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There are no production effects dueto temperature changes in the oil.More accurateAll-electric machines allow machinemovements to be integrated directly

with the control system. This greatlyimproves machine set-up, adjustmentand process control.Improved control means that processmovement and shot weights are oftenten times more accurate thanconventional machines, i.e. shotsweights can be controlled to within0.001 grams (1mg). This increasedprecision improves product quality andreproducibility. It also allows easymonitoring of process parameters andcan be used to improve mould

protection.FasterThe direct drive from motor to machinemovement reduces the system inertia(there are no valves to open or close)and makes the process quicker, moredirect and more controllable. This canlead to significant cycle time reductions(up to 30%) without any loss of productquality.

Maintenance

All-electric machines generally requiremuch less maintenance; hydraulic

systems account for a high proportionof the maintenance needs ofconventional machines. Removing thehydraulic system means:

There are no consumables such as oiland filters to carry

There is no need for cleaning andservicing, or fixing oil leaks

The smaller number of parts meansfewer to service and replace

All-electric moulding

The cost of energy has traditionallybeen between 4 and 5% of the cost ofa moulding, but this is increasingrapidly with rising energy prices.Energy efficiency is not a secondaryissue - it can easily be the differencebetween profit and loss for a company.Despite proven energy efficientperformance and many other benefits,all-electric injection moulding machineshave been slow to penetrate the UKmarket. Early all-electric machineswere more expensive than hydraulicones, but this differential is decreasingrapidly. The important cost is the'whole life' cost (initial cost + operatingcosts) and all-electric moulding

machines offer real and significantsavings in total costs compared withconventional machines.

Energy savings

All-electric injection moulding machineshave the potential to reduce the energy

costs for a moulding by between 30and 60%, depending on the mouldingand the machine. Similar savings arepossible across a broad range ofmaterials and material grades, and canbe achieved even if the cycle time iskept at that required for conventionalmachines. However, in many cases,shorter cycle times are also possible byusing parallel operations (e.g. openingand ejection at the same time) tofurther reduce energy consumption andincrease productivity.All-electric machines also eliminate theneed for cooling the hydraulic system,together with the associated equipmentrequirements and energy use.

Operational benefits

Removing the hydraulic system is oneof the major benefits with all-electricmachines. It brings many benefits,including:

There is no hydraulic oil to bestocked, provided, filtered, changedor disposed of

There is no hydraulic oil to

contaminate the product, theoperations area or the generalenvironment

There is no start-up time delay whilewaiting for the temperature of thehydraulic oil to stabilise

Energy efficiency can be thedifference between profit and

loss for a company.

Servicing is less complex, faster andcheaper.Overall, all-electric machines have amuch lower risk of failure and aregenerally easier and cheaper to

maintain and repair than conventionalmachines.

Secondary Operations

Hydraulic control of cores on existingmoulds that is currently powered by themachine hydraulic system is possible

using an accessory hydraulic powerpack.

CostsAll-electric machines bring significantenergy and cost benefits. Energysavings of 30% are typical, but can riseto 60% if cycle time reductions areconsidered.All-electric machines use less water;depending on the product, waterconsumption can be reduced by up to65%.Improved cycle times and increased

precision gives improved productivity,while the reduced need for productioncapacity can lead to significant costreductions overall.All-electric machines offer a chance forthe UK moulding industry to saveenergy and carbon, while also reducingcosts. Overseas competitors arealready doing it.

All-electric machines cansignificantly reduce the energyconsumption and production

cost for many mouldings.

All-electric machines can show energy efficiency during all phases of theinjection cycle.Opportunities for energy savings through investment are everywhere.

Technology makes it possible to re-equip a factory for lower operatingcosts.


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design conditions.

Tip: Set the extruder to run at its mostefficient speed (usually maximumdesign speed) and control the screwspeed to give an extrusion rate as

close to the maximum as possible andstill produce good product.Motors run most efficiently close totheir design output - a large motor atpart load is less efficient than a smallone at full load.

Tip: Size and control the electricmotor to match the torque needed bythe screw.Optimising the extruder speedmaximises the heat from mechanicalwork and minimises the amount ofelectrical energy needed. Provided the

downstream equipment does not limitthe output, the energy consumptioncan decrease by nearly 50% bydoubling the rotational speed of theextruder.Accurate temperature control isneeded for good extrusion - excesstemperatures are wasted energy. Thepolymer needs to be kept close to theoptimum processing temperature.

Tip: Barrel insulation has a paybackof under 1 year and also reducesHealth and Safety issues and aircurrent fluctuations.

Tip: Check the controls to make surethat the heating and cooling areworking efficiently together.Standby operation can use significantenergy from barrel heaters, coolingwater, calibration vacuum and lights.

Tip: Find the minimum standbysettings and set a routine to alwaysleave machines in this condition.

Tip: Turn off barrel heaters andcooling fans between runs.

Tip: Turn off cooling water on idlemachines.

Energy use can be used as adiagnostic tool to identify deterioration

Extrusion

Extrusion is not only a final formingprocess but is also an intermediateprocess for other processingtechniques such as injection moulding,blow moulding and film blowing. Theefficient operation of extrusion screwsis therefore essential to much of theplastics processing industry. Theprocess is highly dependent onelectricity and most of the energy usedis directly related to machine operation.For profile extrusion the energy used todrive the extruder itself is 50% of thetotal and the remaining energy is usedfor items such as ancillaries andutilities.Surveys show that a typical company

should be able to reduce energy usageby 10% without major capital outlay.

The extruder

The initial cost of energy efficientextruders may be higher but they willgive rapid returns on the extra

investment. Options such as highefficiency AC motors and VariableSpeed Drives have good payback forboth new purchases and whenreplacing motors and drives.Whatever the age of the machine, it isessential to get the right extruder forthe job and the screw diameter anddesign should be checked to makesure they are right for the polymer andproduct.

Tip: Using large extruders for smallprofiles is wasteful.

Tip: Total efficiency (including energyefficiency) is best operating at the

of the machine condition and the needfor maintenance

Tip: Increasing the frequency ofmaintenance costs time and money butcan lead to significant energy savings.

The ancillariesThe main opportunities for energysaving in ancillaries are in minimisingthe demand for utilities, such asvacuum and compressed air. Theelectric motor drives are generallysmall so replacement with efficientmotors is only likely to be cost effectivewhen motors fail. Specifying energyefficient features at the design stagewill give rapid paybacks on anyadditional costs.The first step is to get the extruder

right - if the extruder is at the optimumconditions the need for downstreamcooling and calibration will beminimised. For utilities the approachshould be to minimise the demand andthen optimise the supply.

Tip: Find the maximum acceptableextrudate temperature after coolingand set the maximum cooling watertemperature to achieve this.

Tip: Check that cooling water is notcirculating through idle calibrators.

Tip: Check that cooling water istreated, chilled and distributedefficiently.

Tip: Check that compressed air is notsupplied to idle machines.

Tip: Check that compressed air isgenerated and distributed efficiently atthe minimum pressure needed by theprocess.

Tip: Check that the vacuum supply isthe minimum needed and that it isgenerated and distributed efficiently.

Tip: Check that the vacuum supply isswitched off when it is not needed.

Tip: If replacing electrical motors then

match the size to the actual demandand fit energy efficient motors.

Management

Tweaking of machines by setters andoperators causes more lost time andenergy than any other cause.

Tip: Get the machines set right,record the settings and do not changethem unless absolutely necessary.Increased maintenance involvesadditional effort and costs but can leadto significant energy savings.

Tip: Set up a total productive

maintenance (TPM) programme tokeep all machines and systems in topcondition.Energy efficiency will save money -start an energy managementprogramme today and improve profits.

The cost of energy to extrusion companies

Extrusion is a key formingprocess and is integral to many

other processes


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Extrusion blow moulding

For blow moulding, the Specific EnergyConsumption (the energy used toprocess a kg of polymer) varies fromtypical values of 1.5 - 2.0 kWh/kg upto high values of greater than 3.0kWh/kg. If your factory SEC is greaterthan 2.0 kWh/kg there are some realsavings to be made from energyefficiency and experience shows thatenergy savings of 5 to 10% can bemade through simple low costmeasures. For a company with aturnover of 5 million this meanssaving 10,000 to 20,000 per year forminimal expense. With rising energyprices and the Climate Change Levy,energy inefficient firms will be at a

considerable commercialdisadvantage.

Machine

The major component of energy use isthe extruder area which typically uses40% of the total energy (see previousWorksheet on extrusion). As with otherprocesses, energy efficient machineshave lower long-term operating coststhan standard machines will pay backany extra investment.The use of all-electric machines is anenergy efficient option for blow

moulding because these machinesremove the energy losses at theelectro-hydraulic interface and canreduce energy costs.Whatever type of machine is used,good process parameter control givesefficient operation and can give hugesavings.

Tip: Use just enough energy tocomplete each process stage. Look foropportunities to reduce heating time,cooling time and other cycle stages tosave energy.

Tip: Process controller improvements

make it worthwhile investigatingupgrades. Controlled, accurate andminimised wall thickness and parisonlength, will improve energy efficiency

and materials usage.Blow moulding machines use onlysmall amounts of externally appliedheat (most is generated mechanically)but heat transfer from barrel heaters

can be maximised and evenlydistributed by good seating to thebarrel and the use of a conductivemetal compounds. The energy usedwill be reduced and controlled by barrelinsulation jackets - these also improveHealth and Safety, reduce start-uptimes and generally have a pay-back ofless than 1 year.

Tip: Set the polymer at the minimumtemperature it actually needs.

Tip: Turn off barrel heaters andcooling fans between runs.

Parison weights are often up to 40%more than the weight of the finalproduct. Any trimmed materials (topsand tails) can be recycled andrecovered but the energy used is lostforever. Large tops and tails cost realmoney even if the material is recycled.

Tip: Improved control of the parisonand final product size will improveenergy and process efficiency.

Tip: The amount regranulated variesfrom under 10% to nearly 80%. Youcan improve in this area.Regranulation should be done off-line

(at night) to minimise energy costs, butfirst minimise tops and tail production -reduce and then recycle.When a machine is not producing for ashort time it is not practical to shutdown the extruder but shutting downthe hydraulic systems can giveconsiderable energy savings.Start-up procedures can be set to bringthe energy demands online at the bestpossible time, i.e. heaters untilstabilised, hydraulics and finally theextruder drive. Similarly shutdown

procedures can be developed to switchoff the energy intensive areas of themachine.

Tip: Develop start-up and shut-downprocedures to save energy and time.

Ancillaries

Parison forming must be completebefore the outside surface chills andstops surface texture formation. Thecompressed air pressure for blowing

should be just sufficient to form theparison before chilling but it can thenbe reduced to hold the parison againstthe mould surface.

Tip: Excessive air pressures forblowing or holding wastes energy.

Most of the heat put in during themelting stage must be removed beforethe product is released from the die.Product cooling time is about 50% ofthe cycle time and minimisation of themelt temperature will save energy inheating and cooling as well as reducing

the cycle time.Tip: Setters may raise temperaturesor increase cooling times to get a jobrunning - Check the settings.The chiller system uses large amountsof energy and the process efficiencyaffects both time taken and energyused. Water has a better coolingefficiency than air and bubbles in thecooling water will decrease theefficiency of the cooling.

Tip: Seal, degas and pressurise thewater cooling system.Cooling is most efficient with goodcontact between the parison and mouldand this should be kept by the air feedduring cooling.Hydraulic systems for mould closingshould be matched to the demand(blowing pressure x projected area) toreduce the energy needed and thehydraulic oil should be de-aerated on aregular basis to improve the efficiencyof the hydraulic system. Thehydraulic fluid should also be kept at asteady temperature to improve theprocess control and prolong the life of

the oil.Tip: Some companies use chilledwater from mould cooling to cool thehydraulic oil. This may make thehydraulic oil too cool and give rapidviscosity changes and control andquality problems. Check thetemperature.

General Tip

The real secret to reducing energyconsumption and costs is not in thetechnical aspects of any process - it isin the management attitude.

A desire to reduce costs throughenergy management and an effectiveimplementation, monitoring andtargeting programme will produce theresults and the commercial benefits.Electricity use in a typical blow moulding factory

Total sitecompressed air

(21%)

Blow mouldingmachines

(52%)

Chillers (14%)

Granulation (1%)

6%

52%

21%

14%1%

6%

Lighting (6%)

Pumps (6%)


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efficiency due to a lack of routinemaintenance.

Tip: Service chillers regularly andkeep records of plant conditions.

Tip: Clean evaporators, air blastcoolers and heat exchanger surfaces

regularly.Tip: Check flow/return temperaturesand system flow rates to verify theseare correct and optimised.

Tip: It is a legal requirement to keepsystems gas tight and to repair gasleaks.

Tip: Design moulds and cooling bathsor spray tanks to provide good heattransfer from the plastic to the coolingwater.

Tip: Set all systems components toturn off automatically when not in use.

compressor that pumps refrigerant; forevery 100 kW of cooling capacity, it willuse about 30 kWh of electricity. Even asmall plastics processing site can needa 200 kW chiller, with an operating cost

of over 16,000/year. However, simplemeasures can often improve theenergy efficiency of chillerssignificantly.

Cooling load

Eliminating or reducing cooling loadswill reduce running costs and improveefficiency.

Tip: Only supply cooling whereneeded.

Tip: Use the maximum possible watertemperature; a 1C rise in the supplytemperature reduces the energy

required by about 3%.Tip: Fit adequate insulation tominimise unnecessary loads on thechiller.

Systems

Minimising the load allows a betterassessment of the system design andparticularly how it responds to partloads.

Tip: Optimise existing systems. Usethe most suitable refrigerant andoptimise the system for high part-loadand winter efficiency. This is

particularly important when additionalchillers have been added to thesystem.

Tip: Balance pumps and chillers andmatch them to the normal load (withcontrols to match a variable load).

Tip: Check that pipework and pumpsare sized correctly for currentdemands.

Tip: Keep chillers well ventilated toprovide good airflow over thecondensers.

Tip: Use heat recovery to provideenergy for space heating and hotwater.Components

Component selection is anotherimportant factor in energy efficientoperation.

Tip: Scroll and screw compressorsare more efficient and can replaceexisting chillers.

Tip: Avoid running chillers at lowloads.

Tip: Use large evaporators andcondensers and avoid direct expansionevaporators if possible.

Tip: Use variable speed drives(VSDs) for pumps and fans to matchthe output to process demands.Operation and maintenanceCooling systems often operate at low

Air blast cooling is possible formost of the year in the UK.

Measures of performance: energyefficiency ratios (EERs)

Coefficient of performance (COP) is

the ratio of the cooling capacity to theabsorbed power of a compressor.

Coefficient of system performance(COSP) is the ratio of the coolingcapacity to the absorbed power ofthe complete system. This includesthe effect of the power consumptionof fans and pumps as well as thecompressor.

COP and COSP can be used toindicate the relative energy efficiencyof the chiller or the system and tocompare systems with one another.

The measurement of COP andCOSP depend on the conditionsused to asses them and should onlybe used for comparison whenidentical conditions are used.

Cooling process water

A reliable and consistent source ofcooling water is essential for fast andrepeatable plastics processing. Coolingprocess water and refrigeration plantuse approximately 11% of all theenergy consumed in manufacturing inthe UK. However, energy and carbonsavings of up to 25% are easilyachievable without any technical risk,simply by implementing good practiceand proven technology.

Tip: Cooling plant is generally reliableand is ignored unless there is aproblem. Regular analysis ofperformance data will quickly detectany losses in efficiency.

Air blast cooling

Low ambient temperatures in the UKand the flow temperatures used inplastics processing mean that use ofair blast cooling can reduce energycosts considerably. Air blast coolingpre-cools the return water from the

process and significantly reduces bothchiller loads and energy use. This canproduce significant energy and carbonsavings for low additional costs.If the ambient temperature falls to 1Cor more below the return watertemperature, then the return water isdiverted through the air blast cooler.The more the ambient temperature isbelow the return water temperature, thegreater the air blast cooling effect. It ispossible to switch off the main chillerwhen the ambient temperature is 3Cbelow the return water temperature.The cost savings generated by usingair blast cooling give a typical paybackperiod on the investment of less than 2years and often as little as 12 months.

Tip: Chillers with new or retrofitted airblast cooling circuits can show largereductions in operating costs.

Tip: Chillers with air blast coolingcircuits have shorter compressorrunning times, lower maintenancecosts and extended chiller life.Air blast coolers are available forcapacities as low as 5 kW with no

effective upper limit as units can belinked together to provide greatercooling capacity.

Chillers

Every conventional chiller is a

Savings of up to 25% arepossible with little technical

risk.

Air blast cooling only

Chiller only

Air blastcooling +

chiller


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thus reducing both energy costs andoversizing problems. A 3% efficiencygain may not sound much, but a 500motor uses approximately 50,000 inenergy over a ten year life and a 3%

saving is 1500 - this is equivalent tothree free motors.

Variable speed drives (VSD)

The speed of an AC motor is fixed bythe number of poles and the supplyfrequency. As a result, the hydraulic

pumps in many processing machinesare driven at a constant speed, eventhough the demand varies considerablyduring the cycle. The flow demandchanges from the hydraulic pump arecontrolled by a relief valve andrecirculation of the hydraulic fluid.Another way of meeting the varyingdemands is to fit a VSD to the motor. AVSD allows the speed of an ac motorto be varied and the pump output canbe matched to the variable demand.The energy demand graph shownwould have considerably fewer peaks

and troughs if a VSD were to be usedon the machine. The application ofVSD can significantly reduce energycosts. Other VSD benefits are:

reduced demand on the hydraulicsystem means that the hydraulic oilruns at a lower temperature andrequires less cooling - an additionalcost saving measure

reduced noise

lower maintenance costs

better all-round performance.VSD can also be applied to fans, water

pumps and air compressors where theload varies considerably. For constantloads, the use of a correctly sizedmotor is the best option.Despite this, the varying loads and thedifficulty of matching the output to theneed will inevitably lead to someenergy losses.

Next steps

Contact Action Energy for informationon motors (GPG002), motormanagement policies (GIL056) andcase studies on the savings possible

with HEMs and VSDs.Start to save real money by choosingthe best motors and systems.

motor needs a decision on whether themotor should be repaired or replaced.Repairing a failed motor may appear tobe a cost-effective action but repair canreduce energy efficiency by up to 1%

and may not be the most economicallong-term action. A motor managementpolicy can provide the rules for makingthe best financial decision.

Motor sizingMotors are most efficient when theirload equals, or is slightly greater than,the rated capacity. Motors can beoverloaded for short periods providedthat there is a later lower load to allowcooling. If machines larger thanneeded are purchased or used thenthe motor will not reach the design load

and will never run at optimumefficiency. Oversized motors areinefficient and equipment needs to becarefully matched with demand. Evensteady loads from extruders, fans,compressors and pumps will fluctuateslightly and the basic operating loadrarely matches a standard motor.The demand graph (below) shows theinstantaneous energy demand during atypical moulding cycle and illustratesthe wide variations in load demandfrom a typical moulding machine.

Tip: It is strongly recommended that

expert advice on motor sizing is soughtto reduce costs.

Tip: Where motors can be accuratelypredicted to run at less than 33%of therated output it is possible to reconfigurethe motor from Delta to Starconnection. This simple low-cost actioncan produce savings of up to 10%.

Tip: VSD will allow motors to run atthe required speed to save energy.

High efficiency motorsThe cost premium for HEM is now verysmall and easily offset by the energy

cost savings that result from their use.HEM achieve efficiency levels of up to3% more than conventional motors andhave a peak efficiency at 75%of load,

Instantaneous energy use of a moulding machine

The life cost of a motor is oftenover 100 times the purchase

cost

Motors and drives

Approximately two-thirds of the energycosts in plastics processing are theresult of electric motor usage. Yetmotors are often overlooked whenconsidering energy usage. The motorsin the main processing equipment suchas compounders, moulders andextruders are obvious but the majorityof motors are hidden in otherequipment such as compressors,pumps and fans. When the energy costof running a motor for 1000 hours canexceed the purchase cost and whenthe whole life costs are often over 100times the purchase cost then failing totake action with all the motors in afactory is expensive!

The motor management policy

The greater importance of runningcosts over the initial purchase pricemeans that companies need to changethe way they look at motors. Decisionsneed to be made on the whole life

cost where all purchase, maintenance,repair and operating costs areconsidered. The energy efficiencyimprovements available with thedevelopment of VSD and highefficiency motors (HEM) mean that, inorder to reduce costs, companies mustdevelop and implement a motormanagement policy for the purchaseand operation of motors. This policyshould include guidelines on:

repair and replacement based onlifetime costing

the specification of HEM for all newpurchasesWhen new motors are required, thebenefits of opting for HEM are obvious.However, the failure of an existing

The energy cost of a motor canexceed the purchase cost in

just 1000 hours of use


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Tip: Switch off compressors duringnon-productive hours. They are oftenonly feeding leaks or creating them.

Tip: Check that compressors are notidling when not needed - they can draw

up to 40% of full power when idling.

Tip: Position air inlets outside ifpossible - it is easier to compress coldair.

Tip: If there is a machine or area thatrequires compressed air longer thanthe rest, consider zoning or adedicated compressor so that otherscan be switched off.

Tip: Investigate electronic sequencingto minimise compressors going on andoff-load.

Tip: Maintain the system - missing amaintenance check increases costs.

Improve distribution

The longer the compressed airpipeline, the higher the pressure lossover the pipeline and the greater thecost of the system.

Tip: Make sure that pipework is notundersized, this causes resistance toairflow and pressure drops.

Tip: Use a ring main arrangement ineach building - air can converge fromtwo directions. This reduces the

pressure drop and makes changes tothe system easier.

Tip: Avoid sharp corners and elbowsin pipework as these cause turbulenceand hence pressure drops.

Reduce treatment costs

Tip: Treat the bulk of air to theminimum quality necessary, eg 40-micron filters are usually sufficient.Specifying 5 micron will increase filterpurchase cost, replacement frequencyand pressure drop.

Tip: Test filters regularly to make sure

pressure drop does not exceed 0.4bar - if the pressure drop is higher than0.4 bar, replace the filters, since thecost of power to overcome this drop isusually greater than the cost of a filter.

Tip: Manual condensate traps areoften left open and act as leaks.Consider fitting electronic traps toreplace these.

Next steps

Compressed air is not free and you cansave at least 30% of the costs ofcompressed air by simple managementsystems and maintenance. Start nowby contacting the Action EnergyHelpline for full information on how toreduce your costs.

Whole life costs for compressors (10 year life cycle)

Compressed air

Compressed air is a convenient andoften essential utility, but it is veryexpensive to produce. In fact, most ofthe energy used to compress air isturned into heat and then lost. At thepoint of use, compressed air costsmore than ten times the equivalentquantity of electrical power, ie anequivalent cost of around 50p/kWh. Atthis price, it should never be wastedand only be used when necessary.

Air also needs to be treated to removemoisture, oil and dirt and the higher thequality required, the greater the energyconsumed by the treatment system.The chart below shows the cost ofcompressor ownership over ten years.In a typical 24-hour day, five and ahalf-day week, a 100 kW motor will useenergy worth around 30,000 per year,assuming the cost of electricity to be45p/unit. At these cost levels, anenergy-efficient system is highly cost-effective, even if it costs slightly moreto install.The cost of compressed air makes it anexpensive resource and the way toachieve the best savings is to minimisethe demand and then to optimise thesupply. Savings up to 30% can bemade by inexpensive goodhousekeeping measures such asmaking end-users aware of the cost ofgenerating compressed air andenlisting their help in reporting leaks.

Minimise demand

Reduce leakage

A significantamount of energy iswasted through leakage. Typically, leakrates are up to 40% (ie 40% of thegenerating power is wasted in feeding

leaks). A 3 mm diameter hole in asystem at 7 bar will leak about 11 litres/sec and cost around 1,000 per year.In a system with numerous leaks, thiscost will multiply rapidly!

Simple leak surveys and maintenancecan produce dramatic cost reductions,and in some cases, leak reporting andrepair have enabled companies to shutdown some compressors for all or mostof their operating time.

Tip: Simple and repeated walk-around surveys, with leaks tagged andrepaired as soon as possible, willsignificantly reduce leakage rates.

Tip: Isolate redundant pipework, thisis often a source of leakage.

Tip: Measure losses due to leakage

and target reductions.Reduce usage

Compressed air is often misusedbecause everyone assumes its cheap.Check every application to see whetherit is essential or simply convenient.

Tip: Stop the use of compressed airfor ventilation or cooling - fans arecheaper and more effective.

Tip: Fit high efficiency air nozzles -payback can be as short as fourmonths.

Tip: Consider the use of electric tools

instead of compressed air tools.Tip: Do not use compressed air forconveying granules or products.

Optimise the supply

Reduce generation costs

The higher the compressed airpressure, the more expensive it is toprovide the air. Twice the pressuremeans four times the energy cost. Thereal needs may be lower than you aresupplying. In some cases, the machinerating is for a 7 bar supply but pressurereducers are fitted inside the machine.

What are your real needs?Tip: Check that compressed air is notbeing generated at a higher pressurethan required.

Compressed air is anexpensive resource. Minimisethe demand and then optimise

the supply.

Energy Cost

Maintenance Cost

Capital Cost

10%

15%

75%


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systems.

Tip: Ensure building insulation andfabric meet the current best practice.Tip - Double glazing can both reduceheat loss and improve comfort. Modern

low-e glass and systems are evenmore effective than standard doubleglazing.

Tip: Condensing boilers are the bestoption for new or replacement smallhot water systems.

LightingAlthough they may only be a relativelysmall part of the overall energy usage,lighting systems offer easilydemonstrable opportunities to saveenergy. Pay attention to areas with:

High or continuous lighting levels and

no or low occupancy. Use occupancysensors or time switches.

Fluorescent tubes at high levelswithout reflectors. The use of reflectorsincreases light levels and the numberof fittings can often be reduced.In lighting, simple measures can savemoney easily and a well-designedlighting system can be a permanentenergy-saving feature. Examples andinformation on improved lightingmethods are available in Good PracticeGuides from the Action Energy

helpline.Tip: Many major lamp manufacturersalso offer advice and contractconsultancy on lighting. Use any freehelp to save energy.

Tip: Replacing normal tungsten bulbswith compact fluorescent (CF) lightingsaves money in the long-term.Although they cost more, CF bulbs useonly 25% of the energy of tungstenbulbs and last about ten times longer.The reduced maintenance costs,especially for lights in high fitments,can easily fund the extra purchase

costs.Tip: High frequency tri-phosphor T8tubes should always be installed whenreplacing or refurbishing existing oldersystems where good colour is needed.For areas where colour is not critical,high pressure sodium lighting is anoption.

Tip: Use natural daylight wherepossible and keep skylights clean toreduce the amount of artificial lightingneeded.

Tip: Research shows that lighting

switched on in the morning will rarelybe switched off until the evening -whatever the changes in daylight levelsin the intervening period. Carry out alighting audit to determine if lightingdemands can be reduced.

Buildings

Buildings-related energy use is oftenseen as secondary but it actuallyrepresents an average of 17% of thetotal energy costs. Buildings-relatedenergy is an easy area in which tomake energy savings because anychanges do not impact on production.In most, cases a simple site survey canreduce costs considerably.

For the plastics processing industry,

recent years have seen vastimprovements in factory buildings andworking conditions. This upgrading ofconditions has produced significantimprovements in all-round siteefficiency, and has resulted in ageneral reduction in the usage ofenergy. However, large opportunitiesstill remain for energy savings in areassuch as lighting, space heating andgeneral hot water supplies.Many processes generate excess heatand it is worth investigating if this canbe used for other purposes, such asspace heating on colder days.

Tip: Processes that involve anyvaporising solvents will require localexhaust ventilation. Processes thatonly generate heat have options forgeneral or local ventilation orpreferably energy recycling through aheat exchanger.

Building audit tips

The starting point to reduce buildingenergy use is an audit of the buildingsand systems. The following tips canserve as a basis for the initial audit.

Existing buildingsImproving the energy efficiency ofexisting buildings can be very cost-

effective and easy to do.

Tip: Reducing heating load is the toppriority, so prevent unnecessary heatloss by making buildings as airtight aspossible. Draught-proofing doors and

windows is cheap but effective.Tip: Automatic fast-acting rollershutters save energy on externalaccess doors used for forklifts andother mechanised access.

Tip: High ceilings increase yourheating costs. Investigate the use offalse ceilings, or destratification fans toblow hot air from the roof space downto the working area.

Tip: Restrict the areas to be heatedby using partitions or local systems tocontrol the key areas. Dont ventilate or

heat the whole building space for a fewsmall areas.

Tip: Do not heat areas where youhave windows or outside doors open.

Tip: Do not heat lightly occupiedstores or warehouses when you areonly trying to prevent excessivedampness.

Tip: Insulate supply pipes to radiators.

Tip: Install tamper-proof thermostatsand controllers to stop staff changingthem. For larger sites, Building EnergyManagement Systems control energycosts without relying on staff.

Improving building energy efficiencyalso improves staff comfort and workoutput

New buildings/refurbishment

New or refurbished buildings are anideal opportunity to reduce long-termcosts. Low energy buildings are notonly cheaper to operate but are morecomfortable for staff.

Tip: Get a copy of GPG304 - ThePurchasers Guide to Energy-EfficientBuildings for Industryfrom the Action

Energy helpline and look for energy-efficient designs with passive solarheating, passive ventilation, addedthermal mass, and natural lighting

Building energy costs are asignificant percentage of the

total energy costs.

ECG018 - Energy Efficiency in Industrial Buildings. The figures below give theaverage annual delivered energy use and cost. The main figures represent anaverage working day of 2.3 eight-hour shifts and the figures in brackets givethe values per eight hour shift worked.

kWh/m2 /m2 % total kWh % total cost

Process 532 (231) 26.60 (11.56) 61.0 82.9Buildings 340 (148) 5.48 (2.38) 39.0 17.1Of the buildings energy use, the space heating element was over 50%:

Space heating 288 (125) 2.88 (1.25) 33.0 9.0

The buildings energy use values from the sample ranged from 300 (130) to550 (239) kWh/m2. Calculate your annual buildings energy use per m2 pershift, and compare it to the sample range above


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Action Energy Publications for the Plastics Sector

For full details of publications get a copy of the Plastics Essentials Pack.

Plastics specific information

Energy in Plastics Processing - A Practical Guide, GPG292Extrusion of thermoplastic pipes and profiles, ECG 055Energy efficient thermoplastics extrusion, GPG 239Reducing electricity use in extrusion-blow moulding of thermoplastics, GPG092Reducing electricity use in injection moulding, GPG048Energy management in a small plastics injection moulding site, GPCS252Energy management in a large plastics injection moulding site, GPCS253

GeneralEnergy Management Pathfinder, GIR063EMMA - The Energy ManageMent Advisor, EMMA98Focus - The managers guide to reducing energy bills

Motors and drivesReducing Energy Consumption of Electric Motors and Drives, GPG002Energy Savings from Motor Management Policies, GIL056

Quick Start - Your Fast Track to Energy Savings in Electric Motor Systems, GIR079Retrofitting AC Variable Speed Drives, GPG014Energy savings in industrial water pumping systems, GPG249Variable Speed Drives on Water Pumps, GPCS088Variable Speed Drives on process plant, GPCS170Purchasing Policy for Higher Efficiency Motors, GPCS222Variable Speed Drives on fans, GPCS232Variable Speed Drives on a Cooling Tower Induced Draught Fan, GPCS270

Compressed airCompressing Air Costs, GPG126Energy Saving in the Filtration and Drying of Compressed Air, GPG216Heat Recovery from Air Compressors, GPG238Energy Savings in the Selection, Control and Maintenance of Air Compressors, GPG241Compressing Air Costs - Generation, ECG040

Compressing Air Costs - Leakage, ECG041Compressing Air Costs - Treatment, ECG042Cost and Energy Savings Achieved by Improvements to a Compressed Air System, GPCS136Compressed Air Costs Reduced Automatic Control, GPCS137Compressed Air Savings Through Leakage Reduction and the Use of High Efficiency Air Nozzles, GPCS346Compressed Air Leakage Reduction Through the Use of Electric Condensate Drain Traps, GPCS369

BuildingsEnergy Efficiency in Lighting for Industrial Buildings - A Guide for Building Managers, GPG158Electric Lighting Controls, GPG160Heating System Option Appraisal - A Managers Guide, GPG182Energy Efficiency in Refurbishment of Industrial Buildings, GPG295The Purchasers Guide to Energy-Efficient Buildings for Industry, GPG304Energy Efficiency in Industrial Buildings, ECG018Energy Use in Offices, ECG019Lighting in warehouses, GPCS157Lighting in factories, GPCS158Energy Efficiency in Refurbishment of Industrial Buildings, GPCS192Energy Efficient Lighting in a High Precision Components Factory, GPCS307Energy Efficient Lighting in Industrial Buildings, GPCS309Controlling energy use in buildings, GIR047

Policy and managementEnergy Champions, GPG067Managing and Motivating Staff to Save Energy, GPG084Energy Efficiency Training & Development, GPG085Energy Efficiency in the Workplace - A Guide for Managers and Staff, GPG133Marketing Energy Efficiency - Raising Staff Awareness, GPG172Developing an effective energy policy, GPG186Managing People, Managing Energy, GPG235Maintaining the Momentum - Sustaining Energy Management, GPG251

Team building and energy saving, GPCS289Running an Awareness Campaign, RAC PACKEnergy Saved by Raising Employees Awareness, GPCS214Investment Appraisal for Industrial Energy Efficiency, GPG069Financial Aspects of Energy Management in Buildings - A Summary, GPG075


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ti-energy worksheets plastics) - tangram

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