Microclimate Modifications For Energy Conservation

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Title:
Microclimate Modifications For Energy Conservation
Physical Description:
Fact sheet
Creator:
Barrick, W.E.
Publisher:
University of Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, EDIS
Place of Publication:
Gainesville, Fla.
Publication Date:

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Collected for University of Florida's Institutional Repository by the UFIR Self-Submittal tool. Submitted by Melanie Mercer.
Publication Status:
Published
General Note:
"Publication date: November 1992."
General Note:
"EES-4"

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Source Institution:
University of Florida Institutional Repository
Holding Location:
University of Florida
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All rights reserved by the submitter.
System ID:
IR00004785:00001


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FactSheetEES-4 November1992 MicroclimateModificationsforEnergyConservation1 W.E.BarrickandR.J.Black2Floridahasahot-humidclimate.Daytime temperaturescanbeabove90F(32.2C)for4to7 monthsayearandhumidity,atthesametime,can riseto50-70%(2).Onlyaboutonefourthofthe year'sclimateisnaturallycomfortable.Duringa smallportionoftheyear,particularlyinnorth Florida,temperaturesaretoocoolforcomfort. Generally,windisanassetforahot-humid region.Windaidsgoodaircirculationthatreduces build-upofheatandhumidity.Besidestheneedto provideforadequateaircirculation,thereisaneed forblockingsolarradiationinordertoreduceheat build-up.Twofactorsareessentialforacomfortable microclimateinFlorida:1)airmovementfor evaporationandcooling,and2)shadeforreduction ofsurfacetemperatureandheatbuild-up. Theideaofusinglandscapingtoreducethe effectsofaharshclimateisnotnew,althoughthe ideaisreferredtobyanewterm,microclimate modification.Today'shighcostofenergymakesit moreimportantthanevertotakeanewlookatusing naturetoreducetheseenergycosts.Nearlyone fourthofenergyconsumedinFloridaisforresidential useandnearly30%ofthatenergycouldbesaved throughpassiveenergyconservationmeasures.NEWCONSTRUCTION OrientationTheorientation,orthewaythehouseis positionedinrelationtotheangleofthesun,isthe firstfactortoconsiderwhenmodifyingthe microclimate.Ifthelongaxisofthehouserunsnorth andsouth,thesurfaceoflongeastandwestwallswill receivesolarradiation.Aneastandwestaxiswill exposeonlythenarrowendwallstothehotFlorida sun. A1979computermodelbasedonatypical concreteblockhomeinnortheastFloridapredicted thattheeast-westorientationwouldresultinmore thana$50savingsontheannualcoolingbill(1).The savingswillbeevengreaterasenergycostscontinue torise.ShadePositioningahousetopreserveanduseshade fromexistingshrubsandtreeswillsavetheenergy usedforremovingexistingvegetation,selectingand plantingnewshrubsandtrees,andwaitingfornew 1.ThisdocumentisFactSheetEES-4,aseriesoftheFloridaEnergyExtensionService,FloridaCooperativeExtensionService,InstituteofFood andAgriculturalSciences,UniversityofFlorida.Publicationdate:November1992. 2.W.E.Barrick,FormerAssistantProfessor,EnvironmentalHorticultureDept.;R.J.Black,AssociateProfessorandExtensionUrban Horticulturist,EnvironmentalHorticultureDept.,CooperativeExtensionService,InstituteofFoodandAgriculturalSciences,Universityof Florida,GainesvilleFL32611. TheFloridaEnergyExtensionServicereceivesfundingfromtheFloridaEnergyOffice,DepartmentofCommunityAffairsandisoperatedbythe UniversityofFlorida'sInstituteofFoodandAgriculturalSciencesthroughtheCooperativeExtensionService.Theinformationcontainedherein istheproductoftheFloridaEnergyExtensionServiceanddoesnotnecessarilyreflecttheviewsoftheFloridaEnergyOffice. TheInstituteofFoodandAgriculturalSciencesisanequalopportunity/affirmativeactionemployerauthorizedtoprovideresearch,educational informationandotherservicesonlytoindividualsandinstitutionsthatfunctionwithoutregardtorace,color,sex,age,handicap,ornational origin.Forinformationonobtainingotherextensionpublications,contactyourcountyCooperativeExtensionServiceoffice. FloridaCooperativeExtensionService/InstituteofFoodandAgriculturalSciences/UniversityofFlorida/ChristineTaylorStephens,Dean

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MicroclimateModificationsforEnergyConservation Page2plantstogrowlargeenoughtoprovideeffective shade.RETROFITTINGEXISTINGHOMES TreesTreeseffectivelyprovideneededshade.With properpruningordesirablecanopyheight,treesmay alsohaveafavorableeffectonaircirculation.Proper placementoftreesrelatestothelocationofthesun duringthetimeofhighheatload.Latitude,timeof day,andtimeofyeararedeterminantsforthe locationofthesunandforthesun'seffectonshade direction.ShrubsMassplantingsofshrubsmaydirectordeflect winddirection.Shrubsmayalsoprovideshadeto reduceglareandreflectedradiationwhilethesunis lowinthesky.Additionalbenefitsmaybederived frommoderatereductionofnoiseandairpollutionby usingmassshrubandtreeplantings.Skilleddesign avoidstheproblemofblockingneededairflow.Cold winterwinds,however,canandshouldbedeflected.VinesandEspalieredPlantsWhenspacemaynotallowtreeplantingsfor shade,viningplantsmayproviderelieffromsolar radiation.Trainedonatrellisorarbor,vinesmay provideacanopysimilartotreecanopy.Vines, however,donotrequirethegroundspacerequiredby atree.Ofcourse,properselectionisessentialto avoidexcessivemaintenance.Thetrellisorarbor shouldbeplacedtoallowadequateaircirculation.GroundCoversandSurfaceMaterialsVegetatedsoilsurfacesaffecttheairtemperature inafavorablemanner.Brickandconcrete,onthe otherhand,reflectsolarradiationandoftencause discomfortfromglareandheat.Asphaltabsorbs solarradiationandre-emitstheenergyaslongwave radiation.Surfacesthatabsorbmoremoisture,such aspinestrawandwoodchipmulch,reflectorre-emit verylittleradiation. Concretepatiosreflectandre-emitconsiderable amountsofsolarradiation.Araisedwoodendeckis coolerbecausewoodisapoorheatconductorandthe raiseddesignallowsairtocirculateunderneath. Drivewaysandwalksareoftenconcrete,brick,or asphalt.Useofmulchingmaterials,treatedwood,or brickwithinterspersinggroundcoverwillproduceless heatbuild-upthanlargeareasofhard,reflective surfaces. Mulchedareasandgroundcoverssuchaslilyturf, mondograss,ivy,anddwarfconfederatejasmine requirelessenergyformaintenancethanturf.When usingturf,selectalawngrassmostsuitabletothesite inordertoreduceenergyusedformaintenance.COLORColorofroofandwallswillaffecttheamountof energyrequiredtocoolandheatahouse.Ina1979 computerstudy(1),a"typical"Floridahousewith lightcoloredpaintandshinglescostlesstocooland slightlymoretoheatthanasimilarhousewithdark coloredpaintandshingles.Thesavingsincoolingthe housewithlightcoloredpaintandshingleswasfar greaterthantheincreasedheatingcosts.The computerstudyrecordeda$55differencebetween thetwohousesorasavingsofnearly71/2%.SCREENSANDFENCINGExceptwhenascreenisdesignedtodivertcold winterwind,screeningandfencinginFloridashould notblockairflow.Inahot-humidclimate,goodair circulationisessentialtoevaporationandrelated cooling.Solidstructuresblocktheneededairflow, deflectingbreezesawayfromtheresidence.Open fencedesign,particularlywherethereissome clearanceatthebottom,allowscoolingbreezesto passthrough.Vegetativescreeningmayalsoblockair movement.Thinningoutdensegrowthandtrimming lowerbrancheswillpromotenaturalcooling.SUMMARYMicroclimatemodificationmaybeachievedby shadingandbyenhancingaircirculation.InFlorida, blockingsolarradiationforatleast80%oftheyear isadvisableforhumancomfort.Enhancingair circulationisneededforatleast60%oftheyear. Skilledlandscapingcanachievesuchmodifications efficientlyandeconomically.

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MicroclimateModificationsforEnergyConservation Page3LITERATURECITED1.Buffington,K.D.1979. Economicsof LandscapingFeaturesforConservingEnergyin Residences.Proc.Fla.StateHort.Soc.92:216220. 2.U.S.Dept.ofHousingandUrbanDevelopment. OfficeofPolicyDevelopmentandResearch. RegionalGuidelinesforBuildingPassiveEnergy ConservingHomes.ACKNOWLEDGEMENTSTheassistanceofLyndaA.Johnsoninthe preparationofthemanuscriptissincerelyappreciated.