34 Oncology IssuesMay/June 2010

Becoming more energy efficientallows community cancer centers to reduce expenses,whilesimultaneouslyimprovingthecareenvironmentforpatients, family, and staff. Sustainability has become theindustrystandardinthedesignofnewbuildings;however,existing community cancer centers can be inexpensivelyrenovatedtominimizeenergyusage.Thefollowingaresixprovenstrategiesforadaptingexteriorbuildingmaterials,lighting,andmechanicalsystemstonetlowerutilitybills.

1. Switch to Double-Paned GlassPatients receiving chemotherapy in one location for longperiodsoftimemaybeexposedtoexcessivedraftsorover-heating due to aging windows. Upgrading a building’sthermal envelope through insulation retrofits or glazingupgradescanreduceheatingandcoolingloads,minimizeenergyconsumption,andcreateamorecomfortableenvi-ronmentforpatientsandstaff.

Glazingisoneoftheleadingsourcesofheatgaindur-ing thesummerandheat lossduring thewinter.Glazingupgrades can drastically reduce energy consumption andimproveoccupantcomfort.Upgradingfromsingle-panedclearglasstoadouble-panedinsulatingunitwithareflec-tive coating can reduce heat transmission by 60 percent,improvingthequalityoftheinteriorenvironment.Thekey

toselectinganappropriateglazingsystemistomaximizethe energy performance while providing adequate visiblelight transmittance. Where full glazing replacements arenotfeasible,field-appliedtintsorfilmsonexistingglazingsystemscanreducecoolingloadsandmitigateglareissues.

2. Go VolumetricIfacommunitycancercenterhasnotupgradeditslightingsysteminthepasttenyearsforenergyefficiency,tremen-dousroomexistsforimprovement.Inadditiontoimprov-ingenergyefficiency,manyoftheseoptionsalsoimprovethequalityoflighting.

TheeasyfirststepistoswitchfromT12toT8lampsand electronic ballasts. These lamp ballast combinationsaremuchmoreefficientthanT12magneticballastsofthepast and will pay back in less than three years time. Anin-houseelectriciancanimplementasimplelampandbal-lastupgrade,butnotethatthesocketswillalsoneedtobeupgraded.

Another option is to switch from parabolic fixtures,whichdrivelightdownwardscreatingroomswithdarkwallsandacave-likeenvironment, tovolumetric lighting.Volu-metriclightingretrofitscancuttheenergyusedbymorethan40percent.Retrofittingtovolumetriclightingthatismorediffusealsoprovidesabrighteroverallspace.Theimageson

page35showthedifferenceinthelightgeneratedfromthesetwotypesoffix-tures.

Ifafacilityhasincandescentlight-ing, there are options for energy sav-ingswithretrofitlamps.Compactfluo-rescentswithbuilt-inballastsareviableoptions for non-dimming conditions.LEDretrofitsarenowon themarketandhaveahigherinitialcost,butwilllastlongerthanfluorescents,aredim-mable, andhavenomercury that cancreateahazarduponburnout.Whilestillexpensive,thepriceofLEDretro-fitsisbecomingmorereasonable.

Bi-level stairway lightingfixtureswithbuilt-inoccupancysensorsareanexcellent investment. Since inpatientstairwelllightsareonaroundtheclock,thesesensorsmorethanpayforthem-selves.Stairwellscanbedimlylitwhenunoccupied and then bump up to ahigherleveloflightingwhenoccupantsenter.Thebi-leveloptionisagreatway

At Memorial Sloan-Kettering Cancer Center, New York, N.Y., glazing reduces energy consumption and improves comfort.

by Mary alcaraz, PE, lEEDaP, lc, anD Jason FiErko, PE, cEM, lEEDaP6StrategiesforEnergySavingsinCommunityCancerCenters

Ph

oto

gr

aP

hs

co

ur

te

sy

of

ew

ing

co

le

Oncology IssuesMay/June 2010 35

tosaveenergyineitherretrofitornewconstruction.

3. Seize ControlThefirsttieroflightingcontrolsavingscomeswiththeuseof wall mounted or ceiling mounted occupancy sensors.Thepay-backinenergysavingsistypicallylessthanthreeyears.

A second tier option is to convert to a centralizedsystem. Depending on the existing lighting panels, thisconversionmaybeasimpleretrofit.Forcommunitycan-cercenters,acentralizedsystemoffersseveraladvantages,including:■■ Theabilitytoautomaticallyturnlightsofffortimeof

day■■ Maintenancecontrolthroughaweb-basedinterface■■ Controlsthatcanbeintegratedwiththeexistingbuild-

ingautomationsystem.

Another type of centralized control is a relay-based sys-

tem where a panel can beplacedadjacenttotheexistingcontrolpanelandcircuits re-routed throughtherelays forautomatedcontrol.

Decentralized controlsystems are available wherethecontrolmodulesareactu-allyatthefixtureorareatobecontrolled.Thesesystemsarewell-suitedtoofficebuildingsor areas where daylight har-vesting can be implemented.(Daylight harvesting can bedefined as a control systemthat reduces artificial light inbuildinginteriorswhennatu-rallightisavailable,toreduce

energyconsumption.)

4. Get the Most from Your Motor Variableflowmechanicalsystemsmatchedwithpumporfanmotorsdrivenbyvariablespeeddrives(VSD)havethepotential for largeenergysavings.Sincethepoweruseofamotor changeswith speed, large energy savings canbeachievedbyreducingmotorspeedstomatchactual loadsinthesystem.TheinstallationofaVSDonanexistingcon-stantflowsystemcansaveenergyconsumptionupwardsof50percentandpaybackwithintwotofiveyears.Commu-nitycancercentersmaybegoodcandidatesforupgradingair-handling systems to VSDs because they have specificoccupancyschedulesandtypicallyincludealargeamountofwindows,whichhaveahighlyvariableheatingandcool-ingloaddependingontheoutdoorconditions.

TheuseofVSDsisnotlimitedtoairorwatersystems.VSDshavealsobeensuccessfullyincorporatedoncoolingtowerfansandchillerstoimproveefficiencyattimeswhenthecoolingtowerisnotrequiredtooperateatitsfulldesigncapacity.

5. Renew, Reuse, RecycleAll community cancer centers have multiple streams ofwasteenergythatcanberecycledandreused.Thesewastestreamscan take the formof exhaust air frombuildings,boiler blow down, or boiler exhaust flue gases. The firststep increatinganenergyrecoveryplan is to identifyallof thewasteenergystreams fromyour facility.Once thestreamsareidentified,youcanfocusontransferringenergyfrombuildingexhaustairintotheoutdoorairventilationsystemtobepre-conditioned.

Outdoorventilationairisrequiredbycodetobeintro-duced into all buildings to provide acceptable indoor air

Volumetric lighting can cut energy use by more than 40 percent and provide a brighter overall space.

Parabolic fixtures drive light downwards, creating rooms with dark walls and a cave-like environment.

36 Oncology IssuesMay/June 2010

quality.Theenergyusedtoheatorcooltheunconditionedoutdoorairisamajorsourceofenergyuseinanyfacility.Inmostbuildings,thesamequantityofairthatisintroducedforventilationisexhaustedtotheatmospheretobalancethebuilding’spressurerelationship.

Airsideenergyrecoveryreclaimstheenergyfromtheexhaust air stream and preconditions the ventilation aircomingintothefacility,reducingoverallenergyuse.Air-sideenergyrecoveryresultsinpre-heatingoftheoutsideairduringtheheatingmodebyusingtheheatintheexhaustairstream,andpre-coolingtheoutsideairduringthecoolingmodebyinjectingheatintotheexhaustairstream.

Althoughseveralmethodsofairsideenergyrecoveryexist, a desiccant wheel that transfers both sensible andlatent energyoften results in large energy savings.Manydesiccanttechnologiescantransferbothheatandmoisture,allowingmoisturetoberetainedinabuildinginthewinterandremovedfromtheventilationairstreaminthesummer.

6. Check Your TemperatureCommunitycancercenterswithacentralizeddirectdigi-talcontrolsystemhavethepotentialtoconsiderablyreduceenergy use with minor revisions to their current controlsequences. For example, resetting water temperatures onchillersystemsbygaugingwithoutdoor-airwet-bulbtem-peraturecanreduceenergyuse.Successinthisstrategyislargelybasedonthechillerperformancemapandshouldbecarefullyreviewedpriortoimplementation.

Similartowatersystems,supplyairtemperaturescanberesetupwardtominimizecoolingandreheating.Thisstrategyrequireseachoccupiedzonetobe“polled”bytheautomationsystemtodeterminethemaximumacceptablesupplyairresettemperature.Whenimplementingthisstrat-egy,youmustmonitorspacehumidity,asincreasedsupplyairtemperaturescanleadtoincreasedhumiditylevels.

Systemscurrentlyusingvariablespeeddrivesforcon-trol are most likely determining the speed of the motor

based on a pressure setpoint in the system.This set point is oftenestablished during peakload times, but may behigher than requiredfor off-peak periods. Apressure reset sequencesetsthepressurecontrolset point to the mini-mumvaluethatprovidesenough water or air tothecriticalequipmentorspace. The implementa-

tionofapressureresetsequencecanprovidehigherturn-downs, reduced energy consumption, and maximize thevalueofthevariablespeeddrive.

Infacilitieswithhighlyvariableoccupancies,demand-controlledventilation(DCV)strategiescangreatlyreduceenergyconsumption.InaDCVsystem,spacecarbondiox-ide levels are monitored and the quantity of ventilationairintroducedintothesystemisadjustedbasedonactualoccupancylevels,insteadofprovidingaconstantquantityof ventilation air regardless of occupancy. Reductions inventilationairflowratesresultinreductionsinenergycon-sumptionforconditioning.

Economizersallowoutdoorairtobeusedforcondi-tioningwhenconditionspermit.Thecontrollercomparestheconditionsinthereturnairstreamtothoseoftheout-sideairandchoosesthebestsource.Economizersarenotlimitedtoairsystems,watersideeconomizers,throughtheuseofaplateandframeheatexchangerbetweenthecon-denserandchilledwatersystems,canbypassthechillerandprovide“free”chilledwaterwhenoutdoorairtemperaturespermit.Watersideeconomizersarerecommendedinfacili-tieswithyear-roundchilledwaterloads,whichisoftenthecaseinhealthcarefacilities.

Carpe DiemThestrategiesdiscussedinthisarticleareonlyasamplingofpotentialenergyconservationopportunitiesavailableincancercenters.Somestrategiesmaybesimpletoimplementwithquickpaybacks,whileothersrequiremore in-depthanalysis.Asenergypricescontinuetoescalate,communitycancercentersshouldaudittheirenergyuseandformulateaplanfordealingwithanuncertainenergyfuture.

Mary Alcaraz, PE, LC, CEM, LEED AP, is an electrical engineer, lighting designer, energy manager and Principal with EwingCole. Jason Fierko, PE, CEM, LEEDAP, is a mechanical engineer at EwingCole in Philadelphia.

At Monter Cancer Center, Lake Success, N.Y., various energy strategies are used to achieve LEED NC [new construction] Silver certification rating.