Compressed Air System Guide: Designing your …

1 Compressed Air System GuideProvided as a Service by Kaeser Compressors, your CompressedAir SystemHow to Determine the System You NeedYour Compressed air System is acritical plant utility. To functionproperly and cost effectively, itmust be carefully designed to fill thespecial needs of your applications. Sixbasic elements demand, compressedair quality, supply, storage, distribution,and control/management must be evaluated and factored into final layoutconsiderations to give you optimumresults at maximum efficiency. All sixelements must work together for thesystem to reach top performance Is your CompressedAir Demand?Determining the true demand in yourcompressed air System can be difficultbut is a critical first step. Air demandoften fluctuates significantly; however, ifactual flow demand at any given time isknown, storage and distribution systemscan be designed to meet demandwithout installing most accurate method ofestablishing demand over time in anexisting System is to monitor the air flowusing a flow meter ( see chart, pg.)

2 3).Flow meters can be installed at variouspoints in the System , but are typicallyinstalled in the main headers. Recordeddata, such as air flow and pressure, canbe evaluated to determine the flowpattern. It is especially important to notethe peaks and valleys in demand andtheir data loggers offer aneffective means to track compressoractivity over time. While they don t direct-ly measure as many System parametersas flow meters, they provide substantialinformation to make an accurate assess-ment of System smaller, less complex systems,the ratio between loaded and unloadedcompressor running time (on-line/off-lineor start/stop times) can indicate averagedemand over a long period of establishing Compressed airdemand for a new System , you mustconsider operating pressure require-ments and the duty cycle of using Compressed air israted by the manufacturer for optimumperformance at a certain pressure andair flow. To design a Compressed air System that delivers uniform pressure, itis necessary to ensure that all tools andequipment work efficiently within anarrow pressure range.

3 If this cannot bedone, you have the option of operatingthe entire System at the higher pressureand regulating pressure down asrequired, adding a booster compressorto increase pressure for a particularapplication, or installing two independent2 Visit our Website: your Compressed Air SystemAir Flow MeasurementKaeser s air flow measurement systemuses mass flow meters to record the actu-al amount of Compressed air being usedat any given time. Flow meters can beinserted into Compressed air pipingwithout interrupting System production,and output standard signals to a recordingdevice that collects the data for local Kaeser representative canestablish an accurate air demand profileand start improving System efficiency witha few simple Demand AnalysisKaeser s exclusive Air Demand Analysis(ADA) provides a complete picture of acompressed air System s operation andperformance. Highly accurate sensors anddata loggers record flow, power consump-tion and pressure during normal operatingconditions.

4 Once the information is chart-ed and analyzed, Kaeser engineers makerecommendations for optimizing the systems working at and artificial demand oftenrepresent a significant portion of youroverall demand. All systems have can be measured in severalways while no pneumatic equipment isrunning: measuring the loaded runningtime of a compressor, timing thepressure drop of the receiver tank whileall compressors are stopped, or measur-ing leakage at the point of use. Yourexisting Compressed air demand willalso include artificial demand caused byexcess System pressure that does notincrease productivity. Artificial demandcan be reduced significantly by installinga regulator at the point of use or a flowcontroller at the beginning of thedistribution Compressed Air System Guide 3 What Air Quality Do You Need?Different applications require differentlevels of Compressed air quality. Becausethe cost of producing Compressed air goesup with each level, it is important to meetbut not exceed the required air qualitylevel.

5 If different sections of your plantrequire different levels of Compressed airquality, it is more economical to treat small-er amounts of Compressed air for a particu-lar application rather than the entire is a typical flow chart reading which can be used to determine actual demand and flow pattern inexisting systems. Flow and pressure are inversely related, as can be seen at Points 1 and 2. Pressuredrops below the desired low pressure set points of 100 psig to 90 psig at Point 3 because the systemcannot deliver the needed flow at Point 4. This can be remedied by adding compressor capacity to supply the needed flow (hatched area), or more efficiently, by adding adequate storage capacity, oreliminating the peak Chart: Existing SystempsigFlow(scfm)Maximum sustainable flowSystem pressure (psig)110 psig100 psig90 psigTIME24531 Average flow demand in new systems can be determined by examining operating pressurerequirements, Compressed air requirements, and the duty cycle of existing total required air delivery in this example is scfm ( scfm + scfm + scfm + scfm).

6 Since the optimum duty cycle of a screw compressor is 100%(although this may vary for other compressor types), the required screw compressor musthave a free air delivery of at least scfm at a gauge pressure of 110 psig to account forpressure differential in the compressor controls and other pressure Flow Demand In New SystemsAir Demand5 scfm12 scfm8 scfm14 scfmWorking Pressure40 psig90 psig90 psig90 psigNumber2111 Utilization Factor50%25%10%20%Effective Air 2 x 5 x x x x scfm3 scfmPneumaticPaint SpraygunPaint SpraygunBlowgun ScrewdriverEquipment@ flat jet@ 3mm flat jet@ 2mmTotal Demand:5 scfm + 3 scfm + .8 scfm + scfm= scfmThe following should be added to Total Demand: for leakages+10%= scfmfor errors+15%= scfmas a reserve+20%= scfmTotal Delivery:= scfmQualityClasses0123456 SOLIDSM aximum Particle Size(microns)as QualityClasses0123456 MOISTUREDew Point C Fas specified-70-94-40-40-20-43387451050 OILL iquid and Gasmg/m3ppmw/was QualityClasses01234564 Visit our Website: Are your SupplyRequirements?

7 Compressed air supply is provided byair compressors. your Compressed airsupply, utilizing sufficient storage andproper distribution, must meet your com-pressed air demand. If supply, storage,and distribution are not in tune,excessive pressure fluctuation will occur,resulting in increased operating cost andreduced compressors are controlled byline pressure. Typically, a drop inpressure signals an increase in demand,which is corrected by increasedcompressor output. Rising pressure,indicating a drop in demand, causes areduction in compressor use various capacity con-trol systems to monitor these changes inpressure and adapt the air supply to thechanging air demand. One of the moreefficient is a load/no load control whichruns the compressor at full load or idle,accommodating the demand plant supply can be providedby either a single compressor or a multi-ple compressor installation which can becentralized or decentralized. Single compressor installations are best suitedto smaller systems or systems whichoperate almost exclusively at full compressor installations offernumerous advantages including:application flexibility (the ability toefficiently adjust to shift demandvariations); maintenance flexibility; theoption of centralized or decentralizedoperation; floor space flexibility; andbackup Much Storage Do YouNeed?

8 your Compressed air storage systemconsists of all the Compressed -aircontaining vessels in your compressedair System . Sufficient storage is criticaland represents available energy that canbe released or replenished at any timeas air receiver tank typicallymakes up the bulk of total storagecapacity. Because some compressorcontrols (start/stop and on-line/off-line)depend on storage to limit maximumcycling frequency at demands less than100% of supply, a properly sized receiv-er tank prevents excessive properly sized receiver tank alsoprovides sufficient storage capacity forany peaks in demands. During peakdemand periods, a poorly designed System will experience a drop inpressure as air in excess of systemcapacity is taken from the not all compressors in a multi-ple compressor System remain on-line atall times, the actual air supply at anygiven time can be less than the totalsystem capacity. During the timerequired to bring additional compressorcapacity on line, stored Compressed aircan be used to prevent any pressuredrop in the System .

9 The amount of stor-age capacity needed depends on theamount of excess demand in cubic feet,available pressure differential betweenthe compressor station and point of use,compressor start-up time, as well as thetime available to replenish storedcompressed controllers are also extremelyimportant. Installation of a flow controllerafter the receiver tank is essential forproviding additional Compressed airwhen needed without downstream pres-sure fluctuations. The flow controllerbasically works like a precisionregulator, increasing or reducing flow tomaintain constant line pressure. It alsoprovides the necessary pressuredifferential between the receiver tankand the System to create storage withoutchanging System pressure To Determine The BestDistribution System ? your Compressed air distribution pipingis your means for transportingcompressed air and represents your linkbetween supply, storage, and ideal distribution System providesa sufficient supply of Compressed air atthe required pressure to all locationsSigma Air ManagerKaeser s Sigma Air Manager is theultimate in Compressed air systemsequencing, monitoring, andmanagement.

10 Combining the benefits ofmodern industrial PC technology withInternet technology to provideunparalleled System control with real-timemonitoring and HTML reporting. Optionalsoftware provides enhanced historicalcharting and reporting as well as remoteaccess capabilities from virtually Compressed air is needed. A net-work of pipelines is used to supplydifferent locations with Compressed flow of Compressed air in pipelines,however, creates friction and results inpressure drop. Pressure drop in thepipelines should, ideally, be no morethan 1 to 2 following steps can be taken toreduce pressure drop: reduce the distance the air must betransported reduce the friction through the pipesby increasing pipe size andeliminating unnecessary elbows,valves, and other flow restrictions reduce the flow rate of air through thesystem select smooth bore piping minimize the drop in pressure acrossthe System components eliminate loss is higher in longer pipesand in pipes with a smaller diameter. Aneffective way to reduce pressure drop isto use a loop System that provides two-way flow at any point in the System , cut-ting the flow in each pipe path in halfand reducing Compressed air more important than pressuredrop caused by friction, however, is thatresulting from the System componentsthemselves.