Robinson, J et al. - Sustainable Control Systems in the Modern Home - ENME 538

SUSTAINABLECONTROLSYSTEMS INTHEMODERNHOME

GROUP10

FINALDESIGNREPORTPROJECTTEAM: NicolasAlexandreHamel-10075091

BraedenDanielHale-10104852RichardMurrayHudson-10104283MatthewLamoureux-10086715JordanRobinson-00290587DanCojocariu-10076421

ACADEMICADVISOR: Dr.KeDu DepartmentofMechanicalEngineering UniversityofCalgaryPROJECTSPONSOR: JohnBrown housebrandFACULTYADVISOR: Dr.SimonLi UniversityofCalgary

ENME538April8,2016

UniversityofCalgary

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EXECUTIVESUMMARY

Sustainabledesignsarebecomingincreasinglyimportanttohomeownersthatnotonlywanttosavemoney,butalsowanttohaveapositiveimpactontheenvironmentanditsresources.Thisprojectwasundertakentoallowtheaveragehomeownertoreducebothenergyusageaswellastreatedwaterusage.Twoautonomoussystemswerevigorouslyconceptualized,createdandtestedtovalidateproofofconcept.Thefirstisanautomatedin-linefansystemthattakesadvantageofthenaturallyoccurringtemperaturesinksintheaveragehome.Thissystemwouldbeusedtoredistributewarmandcoolairwithinthehome,andwouldsupplementtheexistingHVACsystemsalreadypresent.Thesecondisarainwatercollectionanddistributionsystem.Thissystemtakestheguessworkoutofwateringplants.Throughtheuseofmoisturecontentsensorsandapump,optimalsoilconditionsaremaintainedforeachplanttoreduceoverwatering.Throughtestingitwasdeterminedthatbothconceptswerecredible.Thein-linefansystemcooledtheupperstoryofahome50%fasterthannaturalconvection.Aswell,therainwaterdistributionsystemeffectivelyreadsoilsaturationlevelsanddeliveredwaterwhenneeded.ItwasalsodeterminedthatbothsystemshavethepotentialtosavemoneydirectlyandtohaveasignificantimpactonemissionswhendeployedinAlbertahomes.Bothsystemshaveshownpromiseafterpassingthroughtheearlystagesofprototypetestingandarereadyforthenextstepoffull-scaleimplementation.

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ACKNOWLEDGEMENTS

Group10wouldliketothanktheprojectsponsor,JohnBrownforhisassistancewiththe4thyeardesignproject.Moreover,theprojectsponsorhasprovidedmanylearning’sfortheteam.WewouldliketotakethisopportunitytothanktheprojectAdvisor,Dr.KeDufortheguidanceandmentorshiphehasprovidedasthegrouphasprogressedthroughtheproject.Lastly,wewouldliketothanktheDepartmentofMechanicalEngineeringincludingtheprofessoroftheCapstoneDesignCourse,andtheTeachingAssistantsfortheknowledgetheyhavesharedwithus.

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TABLEOFCONTENTS

ExecutiveSummary.....................................................................................................................................2

Acknowledgements.....................................................................................................................................3

TableofContents.........................................................................................................................................4

ListofTables................................................................................................................................................6

TableofFigures............................................................................................................................................6

ProjectOverview.........................................................................................................................................7

Background..............................................................................................................................................7

ProblemStatement..................................................................................................................................8

OverallGoalsandScope..........................................................................................................................8

ProblemDefinition.....................................................................................................................................10

CustomerRequirements........................................................................................................................10

ObjectivesandConstraints....................................................................................................................10

In-lineFanSystem..............................................................................................................................10

RainwaterManagement....................................................................................................................12

DesignFunctionsandSpecifications......................................................................................................14

ConceptGenerationAndSelection............................................................................................................19

DevelopmentandDescriptionsofDesignAlternatives.........................................................................20

In-LineFanSystem.............................................................................................................................21


AssessmentofDesignAlternatives........................................................................................................22

FinalDetailedDesign.................................................................................................................................25

OverviewoftheDesignConcept...........................................................................................................25

In-lineFan..........................................................................................................................................25

RainWaterManagement...................................................................................................................25

OverviewofKeyDesignComponents....................................................................................................25

In-lineFan..........................................................................................................................................25

RainWaterManagement...................................................................................................................26

ProjectCosts..........................................................................................................................................26

In-LineFan..........................................................................................................................................26


FeasibilityandRiskAssessment.............................................................................................................29

In-LineFan..........................................................................................................................................29

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VerificationandPrototypeTesting............................................................................................................34

In-LineFan..........................................................................................................................................34


Recommendations.....................................................................................................................................59

In-lineFan..........................................................................................................................................59


Conclusion.................................................................................................................................................62

References.................................................................................................................................................63

Appendices................................................................................................................................................65

AppendixA–RainwaterManagementExpenseReport........................................................................65

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LISTOFTABLES

Table1In-LineFanObjectiveRanking.......................................................................................................11Table2RainwaterManagementObjectiveRanking..................................................................................13Table3RainwaterManagementMorphologicalChart..............................................................................19Table4RainwaterManagementNumericalEvaluationMatrix.................................................................22Table5In-LineFanNumericalEvaluationMatrix......................................................................................23Table6RainwaterManagementMarkingCriteria....................................................................................23Table7In-LineFanMarkingCriteria..........................................................................................................24

TABLEOFFIGURES

Figure1In-LineFanInputs/Outputs..........................................................................................................15Figure2RainwaterManagementInputs/Outputs.....................................................................................16Figure3In-LineFanFunctionalBlockDiagram..........................................................................................17Figure4RainwaterManagementFunctionalBlockDiagram.....................................................................17Figure5RainwaterManagementFunction-MeansTree...........................................................................20Figure6In-LineFanFunction-MeansTree................................................................................................21Figure7CharacterizationofTMP-36temperaturesensorperformance..................................................35Figure8EffectofAirflowandVibrationofTMP-36Reliability..................................................................35Figure9.Conceptual(left)andPhysical(Right;ArduinoUno)LayoutsofINlineFanControlSysteM......36Figure10.ConceptualDiagramoftheCompletecontrolsystemoftheinlinefansystem.......................37Figure11.BasicthermalmodelofastandardhomewithanintegratedinlineFansystem......................37Figure12UserinterfaceandSystemDisplay.............................................................................................39Figure13ResultsofOperatingIn-LineFanSystem...................................................................................40Figure14SolidWorksModelSimulations..................................................................................................40Figure15FullScaleHome-SolidWorksModel.........................................................................................41Figure16Cut-awayofductat1/20ofscale..............................................................................................42Figure18PictureoftheEC-5Sensor(DecagonDevices,2015).................................................................46Figure19SensorCalibrationEquationsCompared...................................................................................47Figure20SensorThreshold-WateringSoil...............................................................................................48Figure21NoiseFoundinSensor2.............................................................................................................49Figure22DiscrepancyAmongSensorMeans............................................................................................50Figure23LocationofSolderedConnections.............................................................................................51Figure24SensorCalibrationTest-2SensorsinOneCup.........................................................................52Figure25SensorCalibrationTest–2SensorsinOneCupwithWaterAdded..........................................53Figure26PrototypeatDesignFair............................................................................................................54

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PROJECTOVERVIEW

Asconsumershavebecomemoreawareoftheenvironmentalfootprintofthesystemsintheirhomes,theyhaveincreasinglydemandedmoreproductsandservicesthataremoreenvironmentallyfriendly.However,asthenumberandcomplexityofthesesystemsgrows,thedirectandmanualcontrolofthesesystemsisbecomingprohibitive.Theemergenceofinexpensive,lowpower,andpowerfulmicrocontrollerspresentstheopportunitytocontrolsuchsystemsbasedonminimaluserinput.

Inthepresentprojectandreport,weintendtostudytheuseofmicrocontroller-operatedmechanicaldeviceswhichtakeadvantageofnaturally-occurringheatandresourcesinordertosavematerialcostsforhomeownerswhileatthesametimeimprovingthesustainabilityofmodernhomesthroughreductionsingreenhousegasemissionsandtreatedwaterusage.

BACKGROUND

ThecombinedproblemsofacceleratingglobalclimatechangeandlocaleconomicrecessioninAlbertaduetodepressedcommoditypricesareoftenperceivedtohavesolutionsthataremutuallyexclusive.Ontheonehand,technocraticsolutionstotheproblemofgrowinggreenhousegas(GHG)emissionsareoftenperceivedtobecomplex,niche,andprohibitivelyexpensiveforconsumers,whileconsumer-levelsolutionstoaneconomicrecessioninvolvecuttingmonthlyexpensesandtakingfewerrisksonless-proventechnologiesinthehome.Engineeringsolutionswhichcansolvebothproblemssimultaneously,however,presentopportunitiestomakegainswhichwillbewell-receivedbyhomeownersfortheircost-savingsandaboonforglobalclimatechangemitigationduetothecumulativeeffectofwidespreaddeployment,evenwithmodestindividualenvironmentalimpacts.

Sustainablehousingisacrucialelementinthepursuitofglobalclimatechangemitigation.TheGenevaUNCharteronSustainableHousingnotesthat‘sustainablehousinghasakeyroleinthequalityofhumanlife’(UNECE,2015).Aswellasimprovingsocialinclusionandculturaladequacy,sustainablehousingiscentraltoenvironmentalprotectionandtheeconomiceffectivenessofhousingingeneral.TheCharteradvocatesforafocusontheminimizationofenvironmentalimpactsandsustainabilitythroughtheretrofittingofexistinghomes‘asmuchaspossible,fortheefficientuseofresources’aswellas‘improved…energyperformanceofdwellings’(UNECE,2015).

InCanada,andAlbertaparticularly,therearetwocategoriesofenvironmentalimpactswhichofferthegreatestopportunitiesforimprovement:1)HVAC-dependentenergyefficiency,and2)outdoorwaterusage(Reference).In2011,Residentialhousingaccountedfornearly17%ofsecondaryenergyusageinCanada,andtheprimarydriverofenergyconsumptioninresidentialhomesareheating,ventilation,andairconditioning(HVAC)systems(NRCAN,2015).InAlberta,natural-gas-basedfurnacesaccountforjustover90%ofheatingsystemsinstalledinhomes,andairconditioningsystemsareelectricity-intensiveforthetypicallylarge-areahomesfoundinAlberta,andrelyonelectricityderivedfromaheavilypollutingcoal-basedelectricitygrid(NRCAN,2012).Additionally,in2011,Canadacontinuedtobeoneofthelargestper-capitaconsumersoffreshwaterintheworld,andhouseholdsaccountedfor43%ofthetotalfreshwaterusage(StatsCan,2012).Meanwhile,inAlberta,residentialdemandforwaterusagecontinuestogrow,despitetheeconomicrecession,andwatertreatmentplantsarereachingcapacity.ThereisthereforeapressingneedforimprovementsintheenvironmentalimpactsofresidentialhomesinCanada.

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Whilemanyhomeownersmaybemotivatedtoreducetheenvironmentalfootprintoftheirhomes,widescaledeploymentwillbegreaterwithmoreaffordablesolutions.Indeed,Canadianhomeownersactivelyinvestinretrofitsandrenovationstoimprovetheirlivingstandards(StatsCan,2012).AccordingtoStatisticsCanada,between2003and2007,50%ofhomeownerscompletedretrofitsspecificallytoimprovetheenergyefficiencyoftheirhomes,andmorethanaquarterofthoseretrofitsweredirectlyappliedtoexistingHVACsystems(StatsCan,2012;NRCAN,2015).Aswell,homeownersdemonstratedparticularinterestintheinstallationofwaterusagemetersandgreywatermanagementsystemswhereapplicable.

PROBLEMSTATEMENT

Weaimtodesignandanalysetwoautomatedsystemscentraltotheenvironmentalimpactofnormallyoperatinghomes.

1. Anautomatedairredistributionsystemforcoolingandheating 2. Anautomatedrainwatermanagementsystemforcollection,storageanddistributionofrainfall

Bothsystemshavethebenefitofreducingthestressplacedontheenvironmentbyahomeinahighlyfeasibleway.Weintendtoinvestigatetheadvantagesandopportunitiesofferedbytheaforementionedsystems,thenreportonourempiricalanddesignresults.

OVERALLGOALSANDSCOPE

Theprimaryobjectivesofthecurrentprojectaretogeneratefeasibleandaccessiblemechanicalengineeringsolutionsinordertoimprovethesustainabilityofmodernhomes.Specifically,weaimtodevelopsolutionhavingthepotentialgreatestimpacton1)thedirectreductionofwaterandenergycostsforhomeowners,2)thereductionofdirectandindirectenergyusagebyhomeowners,and3)thereductionofcumulativegreenhousegasemissionsandtreatedwaterusagedemandinAlberta,Canada,andglobally.

Inthepursuitofthosegoals,weintendtodeveloptwoelectromechanicalsystemsthathavethepotentialtodecreasetwoofthegreatestenvironmentalimpactsofmodernhomes:energyuseforindoorclimatecontrolandwateruseforoutdoorenvironmentcontrol.Tomitigatetheenergyusage,andsubsequentenvironmentalimpactsoftheformer,weintendtocreateapassiveenergysystemthatwillworkinconcertwithexistingstandardHVACsystems.Tomitigatewaterusage,andlimitthedemandfortreatedwaterusedforlawnmaintenanceandgardening,weintendtocreateanintelligentwatercollectionanddistributionsystemwhichcollectsthemaximumamountofrainwateranddistributeswatertoplantsbasedontheirindividualhorticulturalneeds.

Wewilltestthemechanicalperformanceofthetwosystemsandtheirrespectivesubsystems,bymeasuringandoptimizingresponsetime,controlsystemssensitivity,mechanicalsystemcapabilitiesintermsofheattransferandfluiddynamics,componentperformancelimits,reductionsinenergyandwaterdemand,reductionsinprojectedenvironmentalimpactsandlastbutnotleast,theabilitytorespondtoandprovideforhumancomfortdesiresandplanthorticulturalneeds.

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Ourtwosystemsareintendedtobeadaptabletoanymarketandlocationwhichstandstobenefitfromimprovementsinthemitigationoftheenvironmentalimpactsofstandardhomes,particularlywithrespecttoenergyusage,treatedwaterusage,GHGemissionreductions,andurbangardeningandfarmingactivities.Furthermore,weaimtofundamentallycontrolthecostandaccessibilityofthesesystemsbyimplementingthemechanicallysimplest,andthereforeleastexpensivepossiblesystemsupondeploymentaswellasbydesigningthesystemswithmodularity,suchthattheycanbeeasilytailoredtoavarietyofhomeowners'needs.Bykeepingcostslowanddesigningthesystemstoadapttoavarietyofneeds,weaimtoobtainthegreatestpossibleadoptionratesamongconsumersforsustainablehomesystems.Thiswillnotonlybebeneficialforthegrowthanddistributionofthesesystems,butwillalsohelptogenerateagreaterreductioninthecumulativeenvironmentalimpactsofhomes.

Thebenchmarktargetmarketsforoursystemsisthree-storeysingle-detachedhomesinAlberta,whichhavethegreatestpotentialdemandforhomerenovations.Thatis,wesurmisethathomesbuiltbetween10and30yearsagowillhavethegreatestdemandforsuchsystemssincenewerhomeswilllikelynothavehighdemandfornewbuildingcosts,andhomesolderthan30yearsmaybenefitmorefrommorefundamentalrenovationimprovementssuchasfurnacereplacements,insulation,waterlinefixesandwatermetering.

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PROBLEMDEFINITION

CUSTOMERREQUIREMENTS

Clientsfortheoverallprojectinclude:

1. Housebrandsponsorandcontact(JohnBrown) 2. Homebuyersinterestedinthesesystems 3. Homebuilderstowhomtheproductcouldbemarketed 4. Projectadvisor(Dr.KeDu) 5. MembersoftheCapstoneengineeringdesignteam

Regardlessofwhothecustomersareitisofgreatimportancethatbothproductsarecompletelyautonomous.Customersarelookingforinnovativecontrolsystemstoautomateeverydaysystemslocatedaroundthehome.Thesecustomersarealsointerestedinsavingresourcessuchaswater,electricity,andnaturalgas.Thesecontrolsystemsmustalsobeuserfriendly,withasimpleyeteffectiveuserinterface.

Itisveryimportantthatlabtestedtrialsandexperimentaldataisrecordedtoreinforcethefeasibilityofbothdesignsandtracktheprogressofdevelopment.Themajordeliverableexpectedbytheendoftheprojectisaprototypeofbothsystemstodemonstratetheirfunctionalityalongwithproofofanalysis.Asignificantpartofthisprojectisthecontrolsystemsthatdictatetheinformationtransferandoperationoftherequiredsensorsandactuatorsbythemicroprocessor.Thiswillbedisplayedinbothprototypes,andwillhighlighttheautomateddesignofboththein-linefanandwater-managementprojects.

Itwillalsobeagoodideatoshowcasetheimplementationandinstallationstrategyofbothdesigns.Showcasingthebenefitsandeaseofinstallationwillallowthecustomertoenvisionthefinalproductintheirownhomeandwillstrengthentheoverallconceptoftheproject.

OBJECTIVESANDCONSTRAINTS

IN-LINEFANSYSTEM

CONSIDERATIONANDRANKINGOFPROJECTOBJECTIVESANDCONSTRAINTS

Whentheprojectwasstillinitsearlystages,alistofobjectivesandconstraintsimportanttothedesignandanalysisofthein-linefansystemwasgenerated.Theseobjectivesweresummarizedunderthreemaincategories:

1. Installability-thesystemmustbeeasytointegrateintoexistinghousingsystems 2. Efficiency-thesystemmustreducecostandenergyrequirementstoaddvalue 3. Functionality-thesystemmustoperatebetterthanexistingHVACalternatives

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Thesublevelsofeachcategorywererankedaccordingtotheiroverallrelativeimportancetothefinaldesignasdeterminedatthepreliminarystageofthedesign.

TABLE1IN-LINEFANOBJECTIVERANKING

Category Objective Metric Rank

a.)Installability

i.Modular Lightandeasytolift,xxkg #7

ii.Attachedtostandardductwork Standardizedparts,yes/no #6

iii.Easilyincorporatedintohome Fitsintoducting,squaremeters #4

b.)Efficiency

i.Energy/Environment Energyconsumptionandheatexchange #3

ii.Powerconsumption Powerconsumedeachday,kWh(<1kWh/day) #11

iii.Audibility Minimalnoise,lowestdBpossible #10

iv.Durability Last5yearswithreliabilityof99% #8

v.Partsreadilyavailable UsesO-t-Sparts,yes/no #9

c.)Functional

i.Reachestemperaturein1h Responsetime,degreeC/min #2

ii.Reliablecontrolsystem Mustlast5-10yearswith99%reliability #5

iii.Thermostaticallycontrolled Respondaccuratelytoenvironment,yes/no #1

FIVESPECIFICATIONSCRITICALTOTHEDESIGN

Afterthelistofobjectivesabovewascreated,fiveobjectiveswereselectedasbeingthemostcritical.Itwasdeterminedthatthefollowingspecificationsmustbemetinordertodeemtheprojectasuccess

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uponcompletion.Foreachspecification,ametric(eitherasaminimumbenchmarkorperformancecharacteristic)wasdeclaredandeachwasclassifiedeitherasbeinganissueofperformance,procedure,orvalue.Listedinorderofimportance:

c.iii.)ThermostaticallyControlled(Yes,withacomplimentaryuserinterface)

-Procedure

c.i.)Reachestemperaturewithin1hr.(Temperatureshouldchangeatleast2deg/hr.)

-Performance

b.i.)Energy/Environment(Shouldconsume25%lesspowerthantraditionalHVAC)

-Values

a.iii.)Easilyincorporatedintohome(Systemiscompact;smaller=better)

-Procedure

c.ii.)ReliableControlSystem(Mustlast5-10yearswith99%reliability)

-Procedure

CONSIDERATIONOFHUMANINTERFACECONSTRAINTS

Theinterfaceofthein-linefansystemwasalsoconsidered.Abrieflistofcriticalissuesconcerningtheintegrationofthissystemintoanexistinghomeandthedesignoftheuserinterfacewascompiled.Anidealinterfaceforusersshouldhavethefollowingcharacteristics:

1. Beoperatedasanintelligentthermostat-(Userdefined)a. Timer,DesiredTemperature,TemperatureSchedule

2. Operateindependentlyextraneousvariables(Open/closebutterflyvalvestoredirectairflow)a. Customerinteractionwiththesystemshouldbelimited

3. Bemicro-controlleroperated;acceptsadesiredtemperatureinputfromoperator

RAINWATERMANAGEMENT

CONSIDERATIONANDRANKINGOFPROJECTOBJECTIVESANDCONSTRAINTS

Wehavecreatedalistoftheobjectivesandconstraintsthatareimportanttothedesignandanalysisoftherainwatermanagementsystem.Wehavesummarizedtheseobjectivesunderfourmaincategories:

1. Installability(thesystemmustbeeasytointegrateintoexistinghouses) 2. Efficiency(thesystemmustreducecostandenergyrequirementstobeofvalue) 3. Functionality(thesystemmustoperatebetterthanexistingalternatives) 4. Lifecycle(thesystemmustbedurabletoextendlifetimeandreducemaintenance)

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Thesublevelsofeachcategoryhavebeenrankedaccordingtotheiroverallrelativeimportancetothefinaldesignasdeterminedatthecurrentstageoftheproject.

TABLE2RAINWATERMANAGEMENTOBJECTIVERANKING

Category Objective Metric Rank

a.)Efficiency

i.Easingofenergy/environmentimpact kWhelectrical/litresofwater #8

ii.Reduceoverallwaterconsumption Litresofwatersavedperyear #1

iii.Collectandstorewaterdiscretely Aestheticappeal #7

iv.Footprint

• Audible&Physical

Shouldbequiet(dB)andcompact(square-meters) #9

b.)Lifecycle i.Durability Mustlastxyearswithxx%

reliability #6

ii.Accessibleparts Arereplacementpartsavailable #11

c.)Functionality

i.Abilitytostoreexcessivewater Sizeoftank(litres) #4

ii.Overflowprotection Responsetimetooverflow(sec) #5

iii.Reliablecontrolsystem Mustlastxyearswithxx%reliability #2

iv.Controllerbasedonsoilsaturation Mustmaintainsaturationlevelofxx #3

d.)Installability

i.Systemshouldbeadaptabletodifferenthousinglayoutsandplotsizes

Adaptabilityofthemaincomponentsofthesystem #10

ii.Designshoulddefinetheoptimalamountsandtypesofvegetation

Whatamountofcertainegetativespeciescanbeused #12

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FIVESPECIFICATIONSWHICHARECRITICALTOTHEDESIGN

Aswasdoneforthein-linefansystem,fiveobjectiveswereselectedasbeingmostcritical.Itisimperativethatthesespecificationsareachievedinordertoconsiderthisprojectasasuccessuponcompletion.Themetric,intheformofeitheraminimumbenchmarkorperformancecharacteristicisdeclared;eachisclassifiedeitherasbeinganissueofperformance,procedureorvalue.Listedinorderofimportance:

a.ii)Reduceoverallwaterconsumption(litresofwaterperyeartobedeterminedbasedonlotsize)

-Performance

c.iii)Reliablecontrolsystem(Mustlast5-10yearswith99%reliability)

-Procedure

c.iv)Controllerbasedonsoilconditions(Maintainwatersaturationbasedonvegetation)

-Procedure

c.i)Abilitytostoreexcessivewater(tanksizeinlitresbasedonlotsize)

-Values

c.ii)Overflowprotection(responsetimetooverflowinseconds)

-Values

CONSIDERATIONOFHUMANINTERFACECONSTRAINTS

Theinterfaceofthewatermanagementsystemwasalsoconsidered.Abrieflistofcriticalissuesconcerningtheintegrationofthissystemintoanexistinghomeandthedesignoftheuserinterfacewascompiled.Anidealinterfaceforuserswillhavethefollowingcharacteristics:

1. Beintegratedintohousingwatersupplyintheeventoflowcollectionlevelsa. Tie-intomunicipalpiping,tanklevelfeedbacksensor

2. Beproperlycombinedwithirrigationsystemfordistributiona. Soilsaturationsensor,dispersionnozzles

3. Bemicro-controlleroperatedandprovideeffectiveuserinterface;acceptsadesiredvegetationinputfromoperator

DESIGNFUNCTIONSANDSPECIFICATIONS

Whenitcametodeterminingfunctionsandspecifications,thegroupagreedthatthefunctionsmustinoneformoranothersatisfythefollowingconceptsofthedesign:

• Describewhattheproductdoes

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• Transformaninitialstate(input)intoadesiredfinalstate(output)• Useaseriesofmathematicalexpressionstocontroleachsystem

Whenconsideringproductdesign,itiscrucialthatthedesiredfunctionsoftheproductaredeterminedpriortoaspecificformofthedesignbeingselected.Inotherwords,whatthedesignistoaccomplishshouldbeidentifiedfirst,thenthewayitwillbeaccomplishedshouldbeconsidered.Inengineeringdesign,thefunctionisthetechnicalstartingpointoftheproject.Itsetsthetoneforwhatistobeultimatelyaccomplished.Howtheendstateistobereachedisthendeterminedthroughbrainstormingandresearchuntilaviablesolutionisfound.

Top-levelfunctions,majorsub-functions,andafunctionalblockdiagramwerecreatedtohelpillustratetheintendedpathforeachproject.

1. Identifyingthetoplevelfunction:

a. Thermostaticallycontrolledin-linefani. Reduceenergyconsumedtoheatandcoolahomeii. Use‘natural’heatandcooling(topfloorheat,basementcooling)iii. Controltheflowofairtomaintainasettemperature

b. Rainwatermanagementsystem

i. Reducerainwaterwasteii. Utilizewinterrunoffassnowmeltsinspring(collection,storage)iii. Controlthedistributionofwaterinanefficientway

2. InputsandOutputsofProjects:

a. Thermostaticallycontrolledin-linefan:

FIGURE1IN-LINEFANINPUTS/OUTPUTS


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FIGURE2RAINWATERMANAGEMENTINPUTS/OUTPUTS

3. Sub-functionsoftheproject:

a. Thermostaticallycontrolledin-linefan

i. Abilitytoredirecttheflowofairtomaintainatemperatureii. Airfilteringandotherpassiveairqualitymanagementsystemsmayberequired

andaddedasneeded.iii. Variable control loop; the HVAC system should adapt to different set

temperaturesandcontrolsettings.

b. Rainwatermanagementsystemi. Ability tocontainwateraccording toclimateand location, thevolumeneeded

willmostlikelybeafunctionofthesefactorsplusothersii. Variable control loop, the rainwater management system should adapt the

differentinputparametersandcontrolsettings

4. FunctionalBlockDiagram:


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FIGURE3IN-LINEFANFUNCTIONALBLOCKDIAGRAM


FIGURE4RAINWATERMANAGEMENTFUNCTIONALBLOCKDIAGRAM

5. Scientific&TechnologicalKnowledgeRequired


i. Controlmechanisms(Wandboard,USBCommunications)ii. FluidDynamics(Flow)iii. Thermodynamics(HeatExchange)

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b. Rainwatermanagementsystemi. FluidDynamics(Pumps)ii. ControlSystems(Wandboard,USBCommunications)iii. HorticulturalKnowledge(SoilConditions,Climate,YardConfigurations)

Basedontherequirementsdiscussed,acourseofactionalignedwiththemostimportantaspectsofeachprojectwasdetermined.Astheprojectcontinued,someoftheaspectsdescribedabovechangedwhileotherswereaddeddependingontheresultsofourresearchandtesting.Forexample,astheprojectprogressed,theIn-linefangroupdecidedtouseanArduinoUnomicrocontrollerinsteadoftheWandboard.Bothprojectswererathersimilarsothereweresomeopportunitiestoapplywhatwaslearnedinoneprojecttotheother.

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CONCEPTGENERATIONANDSELECTION

Designconceptsareideasthatsatisfythemajordesignfunctions.Thegenerationoftheseconceptsisthemostcreativeaspectoftheproject,asitrequirestakingafunctionandcreatingamethodofachievingthegoalsetoutbythatfunction.

Onceimportantdesignfunctionsweredetermined,possiblemeanswerethenestablishedtoaccomplishthefunctiongoals.Atotalofthreedesignconceptswerecreatedforthein-linefan,withminimalvariationsfromonetotheother.Creatingseveraldesignpossibilitiesallowedtheproblemtobeviewedfromanumberofangles.Thisway,theoptimalendproductcouldbeidentified.Initiallyitwasdeterminedthattemperaturecontrolwastobeachievedthroughtheutilizationofexistingtemperaturesourcesandsinks.Aswell,airexchangewouldtakeplacethroughforcedconvectioninnewductwork.Areductioninenergywouldbeattributedtoalargerallowedtemperaturedifferencebetweenthebasementandupstairs,meaningthefanwouldrunlessoften.Afiltercouldhavepossiblybeenadded,butatrade-offwasacknowledgedwhencomparingthebenefitsofthefiltertotheimpedanceonairflowandoverallperformance.Asforthecontrolsystem,theinitialapproachwastouseacombinationofaWandboardandMatlabprograming.However,anArduinoboardwoundupreplacingtheWandboardduetoitsavailabilityandeaseofcompatibilitywiththetemperaturesensors.

TABLE3RAINWATERMANAGEMENTMORPHOLOGICALCHART

RainwaterRelocationSystem

ContainLiquid BelowGroundmodularvessel

BelowGroundfixedsizevessel

AboveGroundmulti-vessel

Pond - -

DisperseLiquid Pump HydrostaticPressure CapillaryMethod - - -

MonitorVolume Massflowmeter “FuelGauge”

Sensor FloatStyle RadarSensor

ClimateData

-

CapturingRunoff

Strategiceavestroughplanning - - - - -

MonitorSoil MoistureSensor H20ConcentrationSensor ClimateData - - -

ControlMethod Wandboard Arduino RaspberryPi - - -

Program C++ Labview Matlab Arduino - -

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ContainmentofOverflow RainGarden MunicipalSewage OverflowTank Lawn Huge

Tank -

RelocationofOverflow ConcreteGutter

EavestroughTubing(Above

Ground)

UndergroundPiping(Below

Ground)

- - -

Basedontheabovemorphologicalchart,weareabletoidentifythedesignconceptsthatarebestsuitedtotherequiredfunctionofthesystems.Fortherainwatermanagementsystem,theconceptshighlightedindarkgreyaretheprimarymeansconceptualizedforthefunctionsrequiredandthetermshighlightedinlightgreyarethesecondarymeansforaccomplishingthefunction.

DEVELOPMENTANDDESCRIPTIONSOFDESIGNALTERNATIVES

Anotherwaytorepresentadesign’sbasicandsecondaryfunctionsandmeansisthroughafunction-meanstree.Thisillustrationismorein-depthandeachconceptismadeintoitsowntree.Therectanglesrepresentthefunctionsandthemeansaredepictedbytrapezoids.

FIGURE5RAINWATERMANAGEMENTFUNCTION-MEANSTREE

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FIGURE6IN-LINEFANFUNCTION-MEANSTREE

Usingthetwomethodslistedabove,threecomparabledesignsweregeneratedforeachcontrolsystem.

IN-LINEFANSYSTEM

1. Forcedconvection;existingductwork;largetemperaturedifference,usingsolarthermal;filteredair.

2. Forcedconvection;newductwork;improvedthermalefficiencyofhome;filterpadused.3. Forcedconvection;newductwork;usingsolarthermal;improvedthermalefficiencyofhome;no

filter.

RAINWATERMANAGEMENT

1. AboveGroundVesselwithWandboard,withoverflowtosewage,withscriptprogramming2. BelowGroundVesselwithRaspberryPi,withoverflowtank,withLabviewprogramming3. BelowGroundModularVesselwithArduino,withoverflowtoraingarden,withC++

Programming

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ASSESSMENTOFDESIGNALTERNATIVES

Conceptgenerationresultedwithanumberofworkabledesigns.Subsequentlythenextquestionwashowtopickthebestdesign.Thiswasdonebyclearlycommunicatingwiththestakeholderswhileatthesametime,incorporatingtheobjectivesandmetricspreviouslydefinedtobeofgreatimportance.

Weknewthatwithmanypossible-workingdesigns,itmightbeeasytolosedesigninsightsiftherewastoomuchinformation.Therefore,weacknowledgedthatitisgoodpracticetoevaluate3designconceptswith4-8selectioncriteria.Bothquantitativeandqualitativeinformationwasnecessarytocreateanadeptanalysis.

Throughtheuseofanumericalevaluationmatrix,weeffectivelyorganizedtheanalysisofthedesignconcepts.Theselectioncriteriaanddesignconceptswerelistedalongwiththeobjectivesandconstraintsoftheproject.Conceptsthatviolatetheconstraintswereeliminatedandtheremainderoftheconceptswereassignedscoresbasedondevelopedmetrics.

Belowarethenumericalevaluationmatricesforboththerainwatermanagementandin-linefansystems:

TABLE4RAINWATERMANAGEMENTNUMERICALEVALUATIONMATRIX

DesignParameter ObjectiveorConstraint?

Conceptnumber1

Conceptnumber2

Conceptnumber3

SustainPlantstopreventdying

C Good Good Good

Overflowthatprotectshouse

C Good Good Bad

EasilyInstalled O 90 60 -

UserFriendlyProgramming O 70 80 -

EasilyIntegratedHardware O 80 60 -

Totals: 240 200 -

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TABLE5IN-LINEFANNUMERICALEVALUATIONMATRIX

DesignParameter ObjectiveorConstraint?

Conceptnumber1

Conceptnumber2

Conceptnumber3

FastResponse C Bad Good Good

Thermostatic,AutomatedControl

C Good Good Good

Reliability C Good Good Good

CostControl O 100 100 50

EnergyUse O 0 100 50

Retrofitting O 0 0 0

AirQuality O 100 100 0

Totals: 200 300 100

Thescoresassignedtotheconceptsarebasedonthemarkingcriteriathatcanbeseenbelow.Thesemetricsaredevelopedbasedonthebest,worst,andintermediatescenariospossibleforeachdesignconcept.Themarkingcriteriaisasfollows:

TABLE6RAINWATERMANAGEMENTMARKINGCRITERIA

Score Installability Programming IntegratedHardware

100 2-Day Usedbynovice Cheapandeasytoconfigure

75 4-Day Usedwithmanual Expensivebuteasytoconfigure

50 6-Day UsedwithExternalResearch

Moderatelyexpensiveandmoderatelydifficulttoconfigure

25 8-Day Usedwithexpertguidingyou

Cheapbuthardtoconfigure

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0 10-Day Usedwithcoursetaken Expensiveandhardtoconfigure

TABLE7IN-LINEFANMARKINGCRITERIA

Score CostControl EnergyUse Retrofitting AirQuality

100 RelativelyCheap

<100Wdevices

Easilyinstalledonexistingwork

Principallyresponsibleforimprovinghomeairquality

50 SomeExpenses

100-1000Wdevices

Somecustomization Contributestoimprovinghomeairquality

0 MostExpensive

>1kWdevices Extensivecustomization Haslittle,no,ornegativeimpactonhomeairquality

Throughcompletionofthematriceswerealizedthatitisuncommonforadesignconcepttohaveaperfectscoreandbeawinnerinalloftheselectioncriteria.Thisgivesrisetotrade-offsthatmayrequireconsiderationaswellastheengineeringjudgmentsthatmustbemadetojustifythereasoningbehindthetrade-off.

Inthecaseoftherainwatermanagementsystem,thetrade-offsare:

• Theabovegroundvesseliseasytoinstallbutreducesstoragevolumeandmayfreeze• Labviewmaybeeasytocreate,butscriptcouldbemoreefficientandquickertorunwith

smallermemoryneeded

Basedontheabovetrade-offsandthenumericalevaluationmatrix,thefinaldecisionforthissystemhasbeenmade.WehavedecidedtouseanabovegroundvesselwithWandboardandscriptprogrammingbecauseithasagoodhardwareplatformthatgivesusalotofdevelopmentfreedomeventhoughwehavelimiteduseinthewintermonths.

Inthecaseofthein-linefansystem,thetrade-offswere:

• AirQualityvs.Performance:Betterairqualitycomesatthecostoffastresponsetime• Energyefficiencyvs.Performance:Thehighertheperformance,thehigherthepower

consumption,thelowertheefficiency• CostControlvs.EnergyEfficiency:Themoreenergyused,thegreatertheoperationalcosts

Basedontheabovetrade-offsandthenumericalevaluationmatrix,thefinaldecisionforthissystemwasmade.Wedecidedtouseaforcedconvectionsysteminnewductwork,withimprovedthermalefficiencyofthehomeandfilteredaireventhoughthefiltercostmoreperreplacement.However,asthisreportprogressesyouwillseeslightchangesthatoccurredincomparisontothesystemselectedabove.

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FINALDETAILEDDESIGN

OVERVIEWOFTHEDESIGNCONCEPT

IN-LINEFAN

Althoughtheconceptualdesignthatresultedfromtediousobjectiveandmetricconsiderationwasfundamentaltothein-linefanfinaldesign,slightchangesweremadeoverthedetaileddesignstageaswellastheprototypingstage.Intheend,thein-linefansystemconsistsofacolumnofductworkrunningverticallyfromthebasementfloortotheceilingoftheupperstory.Theducthousesareversiblein-linefaninside.Inanactualhome,ductoutletscouldbeplacedonthemainfloor,howeverthiswouldrequireabutterflyvalveandactuatortoredirectairflow;thiswasoutsideofthisproject'sscope.Theplacementofthisductisstronglydependentonindividualhomelayout,andmustbedeterminedbeforehand.Theductshouldideallybeplacedintheareawithgreatestflowdistributionpotential.ThesystemiscontrolledbyanArduinoUnomicrocontrollerthatreceivesindividualfloortemperaturedataintheformofvoltagereadings.Oncealargeenoughtemperaturedifferencebetweenfloorsisachieved,thecontrollerinitiatesthefanandairis,movedtothedesireddestination.

RAINWATERMANAGEMENT

Thedesignconceptwe’vechosentopursuecontainsanabovegroundstoragesystemthatiscomprisedofseveralvesselsthatareconnected.Thisallowsforeasyintegrationintohousesandyardsofdifferentsizes.Theirrigationsystemwillbecompletewithaproperlysizedpump,whichwillprovidethedrivingforceformovingthewatertowhereitisrequiredintheyard.Inordertocontrolwherethewaterwillbedirectedtherewillbezonevalvesthroughoutthenetworkofirrigationtubing,andineachzonetherewillbeasensormonitoringthesoil’smoisturecontent.Thecontrolsystemweplanonimplementingwillreceivethedatafromthesensorsaswellasthevolumeofwaterinthetank.Itwillthendeterminewhichzonesareinneedofwaterandhowmuchwaterisavailabletodistribute.Throughstrategicallyopening/closingthezonevalves,thesystemwillbeabletomaintainoptimalmoistureconditionsforseveraldifferentzones.

OVERVIEWOFKEYDESIGNCOMPONENTS

IN-LINEFAN

Thesystemhas3maincomponents.Firstly,therearetemperaturesensorswithoneplacedoneachlevelofthehometocapturerealtimeinformation.ThisallowstemperaturedifferencesinthehometobemoreaccuratelyrepresentedincomparisontothestandardHVACthermostat,whichtakesasingletemperaturereadingfromoneroom.Secondly,thereisareversiblefanplacedinsidetheducttoallowairflowtooccurinbothdirections.Thisreversibilityallowscoolbasementairtoberedistributedupstairsinthesummertimewhilealsoallowingwarmupstairsairtobecycledintothebasementduringthewintertime.Thirdisthecontrolsystemthatrecordsinputvoltagesfromthesensorsandoutputsavoltagetothefan.Thecontrolsystemisalsoaccompaniedbyagraphicuserinterfacethatallowsthe

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usertosetthedesiredtemperatureandacceptablerange.Theinterfaceallowstheusertocontrolthefanmanuallyifsoinclined.

RAINWATERMANAGEMENT

Thekeycomponentsrequiredtomakethissystemfunctionare:

1. Auserinterfacepromptingtheuserforcertainoperationalrequirements.2. Anirrigationsystemtailoredtothehomesyard.3. Properlysizedrainwaterstoragetank4. Moisturesensors(amountdependentonnumberofzonesandtheirsize)5. A control system capable of automatically distributing collected rainwater throughout a yard

basedontheuserinputs,moisturesensordata,andvolumeofavailablewater.

Theuserinterfacewillbewheretheuserinputsspecificinformationabouttheiryardsothatthecontrolsystemcanproperlymaintainit.Examplesofuserinputswouldbenumberofzones,typesofvegetationinthosezones,desiredwateringtimes,specialrequirements,etc.Ourprototypedidnotincludeauserinterface,asitscreationwasoutsideofourscope.

Theirrigationsystementailsallnecessarysuppliesneededfortransportinganddistributingrainwatertotheyard(pipe,pump,pressuretank,sprinklerheads,emitters,zonevalves,etc.).Thetypesandamountofsuppliesisdependentontheyardsizeandrequirements.Asimpleirrigationsystemwascreatedforourprototype.Itcomprisedofonepump,twosolenoidvalves,andtwomistingnozzles,whichwasallconnectedbytubing.

Theabovegroundstoragevesselsthatweareconsideringonimplementinghaveacapacityof50gallonseachandareabletobeinterconnectedtoincreasethestoragevolumeasnecessary.Therefore,fromacalculatedtanksizeofapproximately1000gallons,thishousewouldneedaround20vessels.Thesevesselscanbeorientedsothattheyfitbetweenthelatticeofafenceorunderneathadeck.

Themoisturesensorsareanintegralparttooursysteminthattheyprovidethefeedbackforourcontrol.Properlyinstallingandcalibratingthesensorsensuresthatthesoilwillbemaintainedaccurately.Asthenumberofzonesorthesizeofeachzoneincreasessodoestheamountofsensorsrequired.Thisistoensurethatthesoilmoistureiseffectivelybeingmonitored.

Thecontrolsystemwillbewhatiscontrollingthedistributionofwaterthroughoutthedifferentzonesintheyard.Byutlizingtheuserinputs,moisturesensordata,andvolumeofavailablerainwater,thesystemisabletocomputewhichzonesrequirewateringandthenstrategicallyopens/closesthezonevalves,aswellaspowersthemotor,untilthedesiredmoisturecontentismet.Forourprototype,thiscontrolsystemwillbecreatedonaWandboardandwillbeprogrammedusingPythoncoding.

PROJECTCOSTS

IN-LINEFAN

Althoughacomplete‘engineeringcostassessment’isnotpracticalatthisphaseoftheproject,acursorydiscussionofthecapitalandoperatingcosts,aswellasthefixedandvariablecomponentsofthelatter,

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willbeattemptedbasedonthebestavailableestimatestodate.Thecapitalcostsofthein-linefansystemarethemajorcontributortothelifetimecostsoftheentiresystem,sincetheenergythesystemintendstouseinordertomaintaintheclimateofthehomeisnaturallyoccurring.Capitalcostsmaybebrokendownintoengineering,procurement,andconstruction(EPC)costs.

Engineeringcostsarethoseassociatedwiththeinitialhomeassessmentandsubsequentdesignofthesystemtailoredtotheparticularhome.Thisprocesscouldbeexpectedtotakeonetotwodays,atwhichpointthepotentialhomeownerwouldbegivenanestimateoftheprocurementofmaterialsandconstructioncosts.However,notallcustomerspresentedwithestimateswouldbeexpectedtopurchasetheretrofit.Thereforethecostofengineeringisthevalueoftwodaysoftheengineers’timedividedbythehomeownerapprovalrate(theratioofthenumberofhomeownerspurchasingthesystemtothenumberofhomeownerscanvassed).However,amoreoptimalnumberwouldbeselectedbasedonthewillingnessofconsumerstopaytheengineeringfee,andthewillingnessoftheengineertoprovideservicesatthatprice.Thepricelistedfortwodaysofengineeringservicesusedinthisanalysisissetat$250.00.

Theprocurementcostsaresimplythecostsofthematerialsusedinthefinishedsystem.Thisisestimatedatroughly$500.00-$700.00basedonthecomplexityoftheinstallation.Thisfigureincludesthecostofthecontrolboard($50),wiring($20),thermocouples($30),reversiblein-linefan($200),ductwork($200),plustheoptionofaddingservo-controlledvents(4x$50).Thecostofthesematerialsarequantity-dependent,thereforethecostwouldbeexpectedtodecreasethegreaterthegrowthinconsumeradoptionrates.

Theconstructioncostsaresimplythecostsofthetimeofthetechniciansemployedtoinstallandcalibratethesystem.Althoughthespecifictimeandvalueofthetimeofthetechnicianscouldbeusedtocalculateaspecificvalue,oftenaconstruction‘multiplier’isusedtoestimatethisvalue.Sincetheinstallationmethodwouldnotbeuniversalforeachhome,arelativelyhighmultiplierof~3wouldbeappropriate.Themultiplierisappliedtotheprojectmaterialcosts.Thereforetheconstructioncostscouldbeexpectedtobebetween$1500and$2100.

Thetotalcostisthesumofeachofthesecomponents,andwouldthereforeberoughlybetween$2,250.00and$3,050.00.AdditionaluncertaintyexistsinthetotalEPCcostsduetothenon-standardnatureofhomes.Thereforeitisdifficulttoestimatewithanydegreeofaccuracytheexactcostoftheductingforeachprojectpriortoengineeringassessment.Ourgrouphavesettledonstatinganestimatedpriceofbetween$3,000.00and$4,000.00foragiveninstallation.

Theannualoperatingcostsarethosecostsassociatedwithfinancing,providingrequiredmaterialandenergy,andmaintainingthesystem.Thefixedoperatingcostsarethosethatarestaticacrossallpayperiods(usuallyoneyeareach),whilevariablecoststendtochangeacrosspayperiods.Duetothelowcapitalcostsofthesystem,financingwilllikelynotbeconsideredformosthomeownersunlessalineofcreditisused.However,thehighinterestratesassociatedwiththisapproachsuggestthatthisapproachwouldlikenotbefrequentlyused.Indeed,wesetthefinancingcostsat$0.Aswell,thein-linefansystemrequireslittleinthewayofmaterialorenergy,exceptfortheenergyrequiredtopowerthesensors,controlboardandfan.Thecontrolboardandsensorswouldtogetherconsume20Wofpower(afixedcost),whilethein-linefancouldbeexpectedtodrawroughly200Wonaverage(avariablecost),dependingonitsusage.Overonemonthofusagewherethesystemhasbeeninuseroughlyhalfthetime,thesystemwouldbeexpectedtouseroughly80kWh,andcouldthereforebeexpectedtocostthe

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homeowneramaximumof$12/mo.and$144/yr.,notincludingtheavoidedenergycostsassociatedwithstandardheatingandcooling.Aswell,wehaveallocatedanadditional$100/yearformaintenancecostsforthehomeowner,whichisalsoavariablecost.Thus,theexpectedoperationalcostsareexpectedtoberoughly$244/year.

RAINWATERMANAGEMENT

Thereisasignificantlyhighercostwhenitcomestothecomponentsfortherainwatermanagementsystem.Thisisduetotheconsiderationoffutureimplementationofthissystemintoaresidentialhousehold.Intotal,thetesting,building,andcompletionoftheprototypecameoutto$1025.09.AbreakdownofalltheindividualcomponentsandtheircostscanbeseenintheexpensereportattachedinAppendixA.Someofthemoremajorcomponentsthataccountforthemajorityofthecostarethemoisturesensors,theWandboardmicrocontroller,thesolenoidvalves,andtheirrigationsupplies.

MOISTURESENSORS

Forthepurposeofdemonstratingthedifferencebetweenseparatezonesinagarden,theprototyperequiredmorethanonesensor.Bearingthatinmind,thedecisionwasmadetobuy3moisturesensors.Atacostof$130persensor,thetotalcostofthesecomponentscametoapproximately$430.Consideringthehighpricepointofthesesensors,extensiveresearchwasdonebeforeorderingthem.Thereareavarietyofoptionsavailablewhenitcomestodetectingthevolumetricwatercontentofsoil,andtheyvaryinpricefrom$2-$300.ThedecisiontogowiththeEC-5sensorsfromDecagonDeviceswasbasedontheirrobustness,accuracy,andsimplisticintegration.Infact,whencomparedtohigherqualitysensorsthatofferaccuratereadings,theEC-5sensorsareoneofthemoreaffordableoptions.

WANDBOARD

ThenextsignificantcomponentoftherainwatermanagementsystemistheWandboardmicrocontroller.Cominginat$150,theWandboardisoneofthemoreexpensivemicrocontrollersonthemarket.WhencomparedtotheArduinoUNOusedforthein-linefansystem,whichcostsaround$50,itisevidentthattheWandboardisanexpensivechoice.Thejustificationbehindthispurchasestemsfromthefutureimplementationoftherainwatermanagementsystem.Moreover,theWandboardoffersanextensiverangeoffeaturesthatareunmatchedinmostmicrocontrollers.Forexample,theabilitytoprogramthecontrolsysteminPythonandimplementitontotheboardwasanimportantfeaturethatspeakstoabilityofthecurrentsystemtoberetrofittedintoaresidentialhome.Mostimportantly,theWandboardhastheabilitytobeaccessedviaWi-Fi.Theaddedbenefitofthisaccessibilityisessentialinthedevelopmentofanappfortheuser.Withthealreadyprovenpotentialofthissystemtosavetheusermoney,waterandtime,theemploymentofanappwouldallowcustomerstoselectthetypeofvegetationthattheyhaveineachzone.WithWi-Fi,thesystemcouldrespondandautomaticallycalibratethesensorstoreflectthetypeofplantthatisbeingwatered.Lastly,theabilitytologintotheWandboardviaWi-Fiallowsthesystemtobewireless,andcanbetweakedwithoutphysicalcontactwiththeboard.

SOLENOIDVALVES

Whenitcomestocontrollingthewaterflowtodifferentzones,thesystemrequirestheuseofseparateirrigationlines.Consideringthateachtypeofvegetationhasadifferentwaterrequirement,thecontrolsystemwillmakedecisionsbasedoneachindividualzone.Becauseofthisnature,thesystemrequires

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theuseofsolenoidvalvesthatcanoperateindependentofthepump.Thepurchaseof3ofthesevalvescostaround$68.Aftertestingandoperation,itwasfoundthatthesevalveswereabletomanagethedeliveryofwatertothezonethattheywereinchargeofbasedonthemoisturerequirements.

IRRIGATIONSUPPLIES

Evidently,alotoftheaforementionedsuppliescanbecategorizedastheelectricalcomponentsoftherainwatermanagementsystem.Tobeabletodemonstratethesystem’sfunctionality,aprototypewasbuiltusingalready-existingirrigationsuppliesfromHomeDepot.Thetotalcostofthesematerialswasapproximately$225anditincludeditemssuchas:irrigationhoses(1/4”and3/4”),hoseconnectors,PVCpipe,lawnsoil,spraynozzles,andapressurereducer.Withtheuseofthesecomponentsandseveralothersnotmentionedinthislist,asimplisticandeffectiveprototypewasdeveloped.Itwasusedtoemulatethedivisionofthegardenintoseparatezonesthatareindividuallycontrolledbythesystem.Amorein-depthdescriptionandoutlineoftheprototypecanbeseeninthe“VerificationandPrototypeTesting”sectionfoundbelow.

FEASIBILITYANDRISKASSESSMENT

IN-LINEFAN

Ananalysisofthefeasibilityofthissystemwhendeployedatfullscaletoprospectiveconsumersrequiresanobjectiveassessmentofthepromiseandtheperilofthesystem.Theformeristhatthein-linefansystemisintendedtosupplementexistingstandardHVACsystemsinAlbertahomesinordertosaveenergyandthereforegreenhousegasemissions.Inaddition,thesystemisfurtherintendedtobeofnetbenefittothehomeowner.Thelatteristhatthesystemisnotabletooffsethomeownercostsatall,andoursystem,whendeployedsimplyredistributesairwithinahouse,costingthehomeownercapital,andfailingtoprovidereductionsintheenvironmentalimpactsofhomes.Ourassessmentoffeasibilityatthisstageshouldbetakenaspreliminary.Althoughwewillattemptheretodeterminetheoverallfeasibilityofthesystemtothebestofourknowledge,thismaychangeasthescopeandcomplexityoftheprojectchanges.Bearingthatinmind,wewillbrieflydiscussfouraspectsoffeasibilityingeneralandwithrespecttooursystem:1)operational,2)technical,3)schedule,and4)economicfeasibility.

Operationalfeasibilityisaqualitativeassessmentoftheprojectedacceptanceofthesystembyconsumersandend-users,andconsistsofestimatinghowthesestakeholders‘feel’aboutusingtheproductinordertogaugehowwillingtheymightbetoacceptingit.Inaddition,itconsidersthe‘usability’oftheproductbyitsendusers.Consideringthelatterfirst,oneoftheprimaryconcernsofourprojectwastotaketheusabilityofthesystemintoaccountwhenconceivingthefinaldesignoftheproduct.Thein-linefansystemisdesignedtofunctionautonomouslyandeffortsweremadewithsuccesstoimplementauser-friendlygraphicalinterface,whichallowstheusertocontrolthepowerofthesystem,aswellastheoperationalmode(off,manual,andautomatic),temperaturesettingandsensitivity.Theautomaticmodeisdesignedtoprogrammaticallyminimizeenergyusagebythein-linefansysteminconjunctionwiththeexistingHVACsystemautonomously.Aswell,theGUIprovidesfeedbackoncurrenttemperaturesandfunctionalstatus,andfutureiterationscouldprovideanestimateofthereal-timeestimatedenergyandcostsavingsbeingprovidedbythesystem.

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Arealtimecostsavingsassessmentmayhelptomitigateapprehensionendusersmayfeelaboutpurchasingsuchasystem.Regardlessofthesuccessfulsimulationsanddemonstrationsoftheeconomicbenefitsofthesystem,usersarelikelytobehesitanttopayforaso-farunprovenproductwithhighercapitalcoststhantheirexistingHVACsystems(evenconsideringthedirectpaybackwiththedeclineinoverallHVACoperatingcostsduetotheenergysavings).Thebestapproachestoensuringthegeneralacceptanceoftheproductistoreduceanybarrierstoentry,includingreducingthecapitalcostsoftheproject,providingfreeengineeringconsultations,andcontinuallydemonstratingthesuccessfulcostsavingsinmodelhome.Finally,asinceredemonstrationofthepotentialofoursystemtomitigateenvironmentalimpactscausebyAlbertahomeswouldalsohelptoincreasethewillingnessofconsumerstospendthemoneyonourproduct.

Technicalfeasibilityconsistsofdetermininghowpracticalthesystemwouldbeandhowreadilyavailablethetechnicalresourcesandexpertisearetobuildandmaintainthesystem.Sinceoursystemconsistsprimarilyof‘offtheshelf’partsandisconfiguredsimilarlytoexistingHVACsystems,ittakesadvantageoftheexistingstandardmaterialsandtechnicalknowledgeofthisverymaturefieldofhomeHVACconstructionandmaintenance.Thein-linefansystemisexceptionallytechnicallyfeasible,andwasdesignedtobeso.TheinstallationprocedureandtimewouldbeidenticaltoretrofittinganyHVACsystemintoasingledetachedhome,beingbothinexpensiveandpracticallysimple.Theonlydifferenceswouldbethetuningofthecontrolsystemtosuittheengineeringassessmentofthethermalcharacteristicsofthehome.Sufficientnaturalheatingandcoolingmustbepresentinorderforthesystemtobeeconomicallyfeasible(moreonthatbelow),butcarefulconsiderationmustalsobegiventotheoptimalplacementoftheductinletsandoutlets(inordertomaximizetheresponsetimeofthesystemandnotdisturbthehomeowners).However,thesystemdoesnotrequireintegrationofhighpowerairconditionersormatingwithanaturalgasfurnace,andsoisroughlyequalintechnicalcomplexitywithstandardHVACsystems.

Schedulefeasibilityissimplythepracticabilityofanytimelineassociatedwiththeprojectgivenourcurrentstateofdevelopmentandthetimerequiredtocompleteanyremainingengineeringtasksandgoals.Typically,a‘feasible’scheduleissetatthebeginningofanyprojectbasedonthebestavailableknowledge.Thefeasibilityofthisscheduleisconstantlyreassessed,particularlywhenresolvingcrisesinthepredicteddevelopmentroadmap.Sincetheschedulewehavesetshouldbefeasible,wewillsimplyoutlinehereajustificationfortheoutlinesassociatedwiththisproject.First,weexpectthatadditionaltestingonfull-scaleprototypesdeployedtostandardfull-sizetesthomeswouldtakejustoverayear.Twomonthswouldberequiredtodevelopthemetricsnecessaryforassessinganygivenfullsizehomeandtestingthemonanumberofappropriatehomesandonemonthsforretrofittingofthein-linefansystemintotheexistinghomelayout.Additionallyafullyearoperationaltestingofthein-linefantodeterminebaselineperformanceandestimatesofexpectedcostsavings.Inthattime,supplychainfortherequiredpartswouldbeestablishedfordeploymentuponthesuccessfulconclusionoftesting.Basedonthedeploymentofsimilartechnologies(suchasothertypesofefficiency-basedretrofits)wecouldexpecttoseeaneventual5%annualgrowthrateinmarketaccess,andbuiltina10-year‘rampup’tothatgrowthrateatanincreaseingrowthof.5%peryear(seeResults–Figure11).

Finally,economicfeasibilityisaquantifiedmeasureofthecost-effectivenessofaproject.Thedeploymentoftheproductdependsmostheavilyontheeconomicfeasibilityofthein-linefansystemfromtheperspectiveofthepotentialconsumer.Agivenhomeownerwouldrequirethatthelifetimecostsofthenewin-linefansystembelessthanthatoftheproportionofHVACsystemitwillbe

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supplementing.Inparticular,theeconomicservicelifeofthein-linefan(includingallcapitalandoperatingcosts,aswellasthecostofborrowingtoinstallthesystem)mustbelessthanthatofthefractionofthesystemitisintendedtosupplement(or‘offset’).Thisrequiresthatthereliabilityofthesystempartsandintegratedcomponentsbereliableforarelativelylongtimehorizon(ontheorderof10to20years).Inaddition,afactorofriskovermustbeappliedtothein-linefanlifetimecoststoaccountfortheadditionallifetimerisktotheupfrontcapitalinvestedbythehomeowner,whocouldsufferloss.

Greaterthan95%ofAlbertahomes(particularlysingledetachedhomesofthekindtargetedasabenchmarkforthisproject)usehighefficiency(>90%)naturalgassystemstoprovideheatfortheirhomes.Aswell,onethirdofsingledetachedhomesinAlbertauseairconditioningforanaverageofsixmonthseveryyear(StatsCan,2012).Thepromiseofthesystemistooffsetsomeproportionoftheseenergydemandsbyusingtheavailableheatsourcesandsinksinthehomeinordertomaximizethatenergy-offsettingfactor.Fromtheeconomicperspectiveofagivenhomeowner,thesystemisfeasibleifandonlyifthenetpresentvalue(thatis,thesumofthesystem’stotalfinancialcostsandbenefitsoveradefinedproductlifetime)ofthenewinstallislessthanthenetpresentvalueofthefractionofexistingHVACsystemweoffset.Ourgoalwastherefore,toincreasethelifetimeofthesystemearlyinourdesignprocessbyusingafewercomponents,andensuringthatasmanycomponentsofthesystemcouldbepurchased‘offtheshelf’andthatthefewrequiredcustomcomponents(fanadapters,motorshields,andappropriatefittings,etc.)wouldhaveahighreliability.Thisgoalof‘designforsimplicity’hastheeffectofkeepingcapitalcostslow,andincreasingtheproductlifetime,bothofwhichincreasetheprobabilityofattractingconsumerstotheproductandoffsettingdirectenvironmentalimpacts.

RAINWATERMANAGEMENT

Similartotheanalysisforthein-linefansystem,thefeasibilityandriskassessmentcomponentsparalleleachotherinthatthepotentialviabilityofthesystemisalwaysfollowedbyapotentialhazardandasolution.Asoutlinedbytheobjectiveoftheproject,therainwatermanagementsystemisdesignedtoautonomouslymanagethevegetationinaresidentialhousehold,whilesavingthecustomermoney,water,andtime.Moreover,thesystemissustainablydesignedtoreducethewaterusagerequiredtoupkeepagardenwhileproducingoptimalplantsandvegetation.Themajorriskthatthesystemfacesisthatitdoesnotinfactsavethecustomerwaterandmoneyandproducesthesameresultasatypicalirrigationsystem.Thesecondaryriskisthatthereisnotmarketforthesystemanditdoesnotreceiveadoptionbythepublic.Inattemptingtoevaluatetheoverallfeasibilityofthesystem,wewilllookatfouraspects:operational,technical,schedule,andeconomical.Additionally,wewilldescribethecurrentsituationwithregardstothemarketadoptionoftherainwatermanagementsystem.

Aspreviouslydefined,operationalfeasibilityisaqualitativeevaluationoftheprojectedacceptanceofthesystembyconsumers,andconsistsofestimatinghowthesestakeholders‘feel’aboutusingtheproduct.Thisisusedinordertogaugehowwillingtheymightbetoacceptit.Additionally,itconsiderstheusabilityoftheproductbyitsendusers.Keepingthatinmind,oneoftheprimaryobjectivesoftheproductdesignwastoconsiderusabilityandfunctionalityforthecustomer.Thatis,therainwatermanagementsystemwasdesignedina“setandforget”mannersuchthatitwouldrequireaonetimesetupandtweakoftheparameters,andthenthesystemwouldoperateautonomouslywithouttheinteractionoftheuser.Tofurtherthedesignforusability,weusedamicrocontrollerthatiscapableofWi-Fiaccesssuchthatanappcouldbedevelopedinthefutureinordertoactasanadjustableuser

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interface.Thesystem’sabilitytooperateinthebackgroundandrequireminimal-to-noadjustmentbytheusermakesthesystemappealingtopotentialcustomers.Furthermore,thecategorizationofthissystemasasustainablechoiceforhomeownerstosavewaterandmoneyisamajorsellingpoint.

Arealtimecostsavingsassessmentmayhelpmitigatetheapprehensionendusersfeelaboutpurchasingsuchasystem.Regardlessofthesuccessfulsimulationsanddemonstrationsoftheeconomicbenefitsofthesystem,usersarelikelytobehesitanttopayforanewproductwithhighercapitalcoststhantheirexistingirrigationsystem.Thebestapproachestoensuringthegeneralacceptanceoftheproductistoreduceanybarrierstoentry.Thisincludesreducingthecapitalcostsoftheproject,providingfreeengineeringconsultations,andcontinuallydemonstratingthesuccessfulcostsavingsinamodelhome.Finally,asinceredemonstrationofthepotentialofoursystemtomitigateenvironmentalimpactscausebyAlbertahomeswouldalsohelptoincreasethewillingnessofconsumerstospendthemoneyonourproduct.

Movingontothetechnicalfeasibilityoftherainwatermanagementsystem,itisimportanttolookathowpracticalthesystemwouldbeandhowreadilyavailablethetechnicalresourcesandexpertisearetobuildandmaintainit.Becauseoursystemcontainsamajorityof‘offtheshelf’partsalongwithintelligentprogramming,ittakesadvantageofexistingstandardmaterialsinthefieldofagricultureandirrigation.Likewise,thereareamajorityofhouseholdsthatcurrentlyhavesomesortofanirrigationsysteminstalled.Itisforthesetworeasonsthatthetechnicalfeasibilityofthisdesignisexceptional.Installingtherainwatermanagementsystemwouldbesimilartotheinstallationofregulararegularirrigationsystemintoaresidentialhousehold,beingpracticallysimple.Therearetwodifferencespresentbetweentheinitialsetupoftheaforementionedsystems.Thefirstisthehigherinitialcapitaloftherainwatermanagement.Becausethesystemisintelligentinitsabilitytocontinuallymonitorsoilmoistureandprovidefeedbacktothedifferentzones,therearesomeadditionalpartsnotfoundintypicalirrigationsystems.Thisisthedrivingfactorforthehigherinitialcapitalinvestmentofimplementingourdesign.Secondly,thetuningofthecontrolsystemisrequiredpriortoitsautonomousoperation.Whatthatlookslikeissimple:theusermustenterthetypeofvegetationineachzoneoftheirgardensuchthatthesystemcanupdatethewaterrequirementsmeasuredbyeachsensor.Onceanappisdeveloped,thisprocesswillbeassimpleasopeningtheappandselectingthetypeofvegetationfromadrop-downmenu.

Schedulefeasibilitysimplyreferstothepracticalityofthetimelineassociatedwiththeprojectgiventhecurrentstateofdevelopmentaswellasthetimerequiredtocompleteanyremainingengineeringtasks.Uponbuildingaprototypeandtestingourproofofconcept,wewereabletovalidatethefunctionalityofthesystemanditsabilitytointelligentlydecidewhenaplantneedswaterbasedonthesoilmoisture.Basedonthecurrentprototype,thepossibilityforoptimizationhasbeenidentifiedandisnecessary.Totrulyensurethatthissystemisreadyfordeployment,thereisaschedulethatneedstoberespectedtoensureasuccessfulresult.First,weexpectthattheoptimizationphasewouldlastforapproximately2months.Whilethatistakingplace,thedevelopmentoftheappwouldbeinprocessandwouldcontinueforanothermonthortwoafterwards.Uponthecompletionoftheappandoptimizationprocesses,anadditional2monthswouldberequiredfortestingandcalibrationofthesystem’sparameters.Inthattime,supplychainfortherequiredpartswouldbeestablishedfordeploymentuponthesuccessfulconclusionoftesting.

Lastly,economicfeasibilityisthequantifiedmeasureofthecosteffectivenessofaproject.Theimplementationofthisproductdependsmostheavilyonitseconomicfeasibilityfromtheperspectiveof

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apotentialconsumer.Agivenhomeownerwouldrequirethatthelifetimecostsoftherainwatermanagementsystembelessthanthatofanirrigationsystemwithallofitsinefficiencies.Inparticular,theservicelifeofthesystemmustbeaccountablesuchthateconomically,itcostslessthantheamountofsavingsitisoffsettingfortheuser.Thisrequiresthatthereliabilityofthesystempartsandintegratedcomponentsbereliableforarelativelylongtimehorizon(ontheorderof10to20years).Withthepromiseofthesysteminmind–toeliminatetheinefficienciesofirrigationsystemsandsavethecustomermoneyandwater–thesystemiseconomicallyfeasibleifandonlyifthenetpresentvalueislessthanthefractionofmoneysavedbyoffsettingtypicalwaterconsumption.Ourgoalwasthereforetoincreasethelifetimeofthesystemearlyinourdesignprocessbyusingfewercomponents,andensuringthatasmanycomponentsofthesystemcouldbepurchased‘offtheshelf’.Thisgoalof‘designforsimplicity’hastheeffectofkeepingcapitalcostslow,andincreasingtheproductlifetime,bothofwhichincreasetheprobabilityofattractingconsumerstotheproductandoffsettingdirectenvironmentalimpacts.

Lastly,feasibilityfromthepointofviewofmarketadoptioniscrucial.Aswithanynewproduct,thereiscompetitionfromsimilarproductsaswellasthecompetitionoftheproductnotbeingadoptedbythemarket.Althoughnotpartoftheprojectrequirements,ourgroupfounditnecessarytoaddresstheissueofmarketadoptionthroughmarketresearch.UpongettingincontactwithLeafandLyre–aspinfarmingbusinessinCalgary–wewereabletoidentifyaninterestinourcurrentsystem.Inthesimplestofterms,spinfarmingisasustainablemovementthattakesproductivityandprofitabilityofahomegardenlottothenextlevel.Moreover,spinfarmersuseplotsofspaceinresidentialhomeowner’sgardenstogroworganicproduceforsalebacktothecommunity.Notonlydoesthismovementsupportthelocaleconomy,butitalsotacklestheissueofsustainabilityinarapidlygrowingpopulation.BasedonthemeetingwithLeafandLyre,wewereabletoreceivemarketvalidationwithregardstoourproduct.TheCEOofthisspinfarmingventureinCalgarywasintriguedbytheideaofthesystemandsawfullpotentialinitsbenefits.Hisinvolvementintheglobalspinfarmingmovementallowedhimtospeakonbehalfofthecommunitywhensayinghowusefulthesystemwouldbe.Notonlydoesitproduceoptimalvegetation(whichisoneoftheaimsofaspinfarmer),butitalsosaveswaterandfocusesontheglobalissueofsustainability.Thesignificanceofthismeetingisevident–ourgroupwasabletovalidatethedesignconceptoftherainwatermanagementsystemwhilefindingamarketfordeploymentinadditiontothetargetmarket(residentialhomeowners).

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VERIFICATIONANDPROTOTYPETESTING

IN-LINEFAN

Althoughthemajorityofourprototypetesting,simulationandscenariomodelingwerecompletedthroughmultipleiterationsratherthansequentially,thetestingresultsdiscussedinthefollowingsectionwillbepresentedlinearlyaccordingtothelevelofanalysis.First,fundamentalcomponenttestingwascompletedtoensurethateachpartofthesystemwascapableofmeetingourbasicdesignconstraintsandalsotoseehowmuchfurtherwecouldpushthecomponentsifnecessary.Forinstance,weneededtoensurethatthetemperaturesensorsprovidedatleast1-2degreesCelsiusofresolutioninpractice,butwealsohopedtohavemoretoimprovetheresponsivenessofthesystem.ThenextlevelofanalysiswastosimulatetheflowenvironmentinSolidWorkstoensureoursystemcouldreasonablychangethetemperatureofourtargetfloorpriortomodelingthatenvironmentwithaphysicalprototype.Wethenmeasuredtheabilityofthephysicalprototypein-linefansystemtomodifythetemperatureofthe1/20thscalemodelhomecomparedtonaturalconvectionandconductionheattransfer.ThetimeresponseresultsofthephysicalmodelwereusedtoprovideconstraintsontheresponsetimeofaSimulink-basedmodelofthehomeinordertomodelthepotentialenergysavingsofthesystemduringdifferentseasons.TheenergysavingswereusedtoestimatethepotentialcostsavingsinSimulink.Finally,scenariomodelingusingWhatIf?TechnologiesCanadianEnergySystemsSimluator(CanESS)wasusedtoderiveanestimateofthepotentialgreenhousegasemissionsreductionsasthesystemisdeployedtohomesacrossAlberta

COMPONENTTESTING:

ThefirsttestsoftheTMP36temperaturesensorassessedthevarianceinthetemperaturemeasurement,andqualitativelyassessedtheresponseofthetemperaturesensortosimplechangesinlocaltemperature(Figure3).Thetemperature'noise'wasroughly+/-0.5degreesCelsiusandisthereforeacceptableforuseinourapplicationwheretemperaturechangesareexpectedtobebetween1and20degreesCelsius.

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FIGURE7CHARACTERIZATIONOFTMP-36TEMPERATURESENSORPERFORMANCE

Totestthestabilityofthetemperaturesensor,temperaturedatawascollectedwhilebeingsubjectedtolowfrequency(10Hz)vibrationaswellashighairflowconditions(~20cubicfeetperminute;Figure8).Thedatawerereplicated(n=7)andwereanalyzedusinga2x2ANOVAwithTukey’s‘honestlysignificantdifference’post-hocmultiplecomparisontests.Vibrationcausedasignificantdropinthetemperaturerecordedbythesensor.However,aneffectofincreasedairflowwasnotobserved,norwasaninteractionbetweenthetwofactorsobserved.

FIGURE8EFFECTOFAIRFLOWANDVIBRATIONOFTMP-36RELIABILITY

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CONTROLSYSTEMLAYOUTANDDESIGN

Abasiccontrolsystemforoperatingthein-linefanwasdesigned(Figure9,10,12)toreadthetemperaturefromthreelocations:1)thetopfloorwhereheatfluxintothesystemgeneratedbyahotairsourcewillbereadbythetopfloorsensor,2)themainfloor,and3)thebasement,wherecoolertemperaturesgeneratedusingdryice(~100gramspertrial)wouldresultinheatfluxoutofthesystem,simulatingaheatsinkforthehome.Theusercouldsetthetemperatureonanyfloor.ThecontrolboardisanArduinoUnoplatformcontrolledbyandprogrammedusingtheMATLAB'ArduinoIOpackage'.Thephysicalcontrolsystemaspresent(Figure9,appliedtoprototypeinFigure11)consistsoftheArduinoUnoPCBwhichreadstheanalogtemperature-dependentvoltagefromthreeTMP36analogtemperaturesensors,eachofwhichiscalibratedpriortouseinthecompletedcontrolsystem.TheArduinodisplaysthetemperaturesinthePC-baseduserinterface(Figure12).Thethermostatsystemthendecidesontheappropriatefansettings(power,fanspeed,anddirection),whichwouldmosteffectivelyandinexpensivelyprovidethedesiredhomeenvironmentconditions,andappliesthosesettingstotheappropriatelydirectedfan(Figure10,11,14)

FIGURE9.CONCEPTUAL(LEFT)ANDPHYSICAL(RIGHT;ARDUINOUNO)LAYOUTSOFINLINEFANCONTROLSYSTEM

ThesystemconsistedofthreeinputTMP36sensors(smallblackunitsmountedinparallelonthebreadboard)whichsendanalogvoltagesignalsreadbytheArduinoUnoboard,anAdafruitV2.3MotorShieldconnectingtworeversiblePCfanstotheUnoboard.RealtimetemperaturedataandDCmotorstatuscanbeoutputandcontrolledthroughaMATLAB-basedinterfacedesignedusingMATLAB’sgraphicaluserinterfacedesignenvironment(Figure12).

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FIGURE10.CONCEPTUALDIAGRAMOFTHECOMPLETECONTROLSYSTEMOFTHEINLINEFANSYSTEM

FIGURE11.BASICTHERMALMODELOFASTANDARDHOMEWITHANINTEGRATEDINLINEFANSYSTEM.

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Figure11demonstratesabasicthermalmodelofastandardthree-storeysingledetachedhomewithanintegratedpassivesolarandgeothermalinlinefansystem.ThismodelwasbasedonthesamehomemodeldevelopedforuseintheSolidWorksflowandtemperaturemodelingsystem,andwasthebasisfortheconstructionofthephysicalprototype,andthethermalmodelsofthesamehomeintheSimulinkmodel.Ontheleft-handsideofthefigure,thebasicheattransferpathwaysaredefinedforthethermalmodelofthehomeandeachfloor,withheatdefinedasflowingintothehomethroughtheroof,fromhigherfloorstolowerfloors,andoutthroughthebasementfloor.Heatisalsolostthroughtheinsulatedwallsoneachfloor.Thisestablishesadiscretetemperatureateachfloorandathermalgradientbetweenfloors(suchthatT3>T2>T1).Aswell,thermalmasses(Cth1,2,3)arepresentoneachfloor.Theinlinefansystemisshownasacolumnwithinletsandoutletsandacentralizedfan.Inthisinstance,theairflowisshownasbeingdrawnfromthefloor1(thebasement)anddirectedtothetopfloor.Thermostatsmaybesetselectivelyoneachfloor(shownontherighthandside)withthesettemperatureoneachbeingsetbytheuser.Ourbenchmarksettemperaturewassetat20+/-1degreeCelsiusforalltestingascloselyaspossible.Outputs(inheavyarrowsleavingthehome)areshownontherightside,andconsistofthetemperaturemeasuredforeachflooraswellasthesettemperaturedesiredbytheuser.

Formal‘testing’ofthissystemhasconsistedofestablishingaseriesoffunctionalprototypeseachmorecomplexthantheprevious.Priortobuildingacontrolsystem,whichcouldeasilycontrolaductfanbasedonenvironmentaltemperatures,theconnectionandoperationofeachcomponenttothecontrolboardthroughsoftwarehadtobeestablished.First,theconnectionofthetemperaturesensorswasperformedandusedtoreadthetemperatureinrealtime.Earlytestingofthissystemwasdirectedtowardsdecreasingthecomputationtimeofeachcontrolsystemloopinordertoincreasetheeffectivesamplingrateofthetemperatureonthesoftwareside.Next,aplotdisplaywasdevelopedtocontinuouslydisplaythetemperaturesimilartothestyleofanoscilloscopeinone-minutesweeps.Followingdebuggingatthisstage,theabilityofMATLABtocontrolatwo-wayvariablespeedDCmotorwasestablished.First,themotorwasattachedthecircuitboardprotectedwithaMOSFET-basedsystemtopreventvoltagefromtheback-emfofthemotordamagingthecontrolboard.FollowinganumberofMOSFETfailures,anofficial‘motorshield’designedbythethird-partyArduinodeveloper‘Adafruit’waspurchasedandwasabletoprovidestableconnectivity.Next,additionaltemperaturesensorswereintegratedintothedesignandprogrammedintothecontrolsoftware.

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FIGURE12USERINTERFACEANDSYSTEMDISPLAY

Figure12illustratesascreencaptureofthesystemdisplayandcontrolinterfacedesignedusingMATLAB’sgraphicaluserinterface(GUI)designenvironment(GUIDE).TheGUIconsistsofthermostatcontrolsintheleft-handpanelwithpowerswitches,settemperatureinputs,andmasterfancontrols('off','manual',and'automated').Intheright-handpanelisarepeatingminute-longchartoftemperaturereadingsalongwithalegenddisplayingthecurrenttemperature,aswellasthe‘power’,‘direction’and‘speed’statusofthein-linefansinthebottomleftcorner.

Oncethesecomponentswereshowntobeabletostablyreadtemperaturesoverareasonableoperationalrangeandusethatinformationtoacontrolafan(thecontrolsystem‘backend’),amorepolishedgraphicaluserinterface(GUI)wasdesignedtoallowmoresimplecontrolofthesystem(Figure6).FunctionswereprogressivelyaddedtotheGUIonceastable,functionalversionhadbeendebuggedandtestedateachstage.OncetheGUIhadbeensufficientlyrefined,aprogramdesignedtorunindependentlyontheArduinowithoutconnectiontothePCwasdesignedusingfirsttheMATLAB-basedenvironment,andtheninthelower-levellanguageoftheArduinointegrateddevelopmentenvironment(IDE)inordertoprovideseveraloptionswithwhichtoprogramthefinalversionofthecontrolsystem.

PHYSICALPROTOTYPETESTING

Inordertoensuretheprototypein-linefansystemwascapableofusingthenaturallyavailableheatsourcesandsinkstocontrolthetemperatureofthehome,wecompleted'proof-of-concept'experimentstodemonstratethatpotential.Asaninitialbenchmark,weassumedtheuserwouldsetthetemperatureofthetopfloorofthehometo20+/-1degreesCelsius.Thebottomfloorwasinitiallycooledto11degreeswhilethetopfloorwasheatedto35degreesusing45secondsofhotairflowdeliveredwithahairdryeron'High'.Wemeasuredtheabilityofthein-linefantomodifythetemperatureintwomodes:an'AB'experimentalmode,anda'BA'mode.IntheABmode,thefloorwasallowedtocoolnaturally('A')andthetimeconstantofthesystemtoreachitssteadystatewasmeasured,thenthein-linefansystemwassetto'automatic'andallowedtocoolthetopfloor(Figure11,12).Thenaturalcoolingofthefloortook335secondstodrivethetemperaturedown63%measured

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fromitinitialstatetothesteadystate(user-set)value(Figure11,'FanOff')andthein-linefansystemprovidedadditionalcoolingpowerevenasthetopfloorslowlyreachtheasymptoticsteadystatevalue.IntheBAmode,thein-linefansystemwasinitiallysetto'automatic'andallowedtocoolthefloor,andthetimeconstantofthesystemtoreachitssteadystatewasmeasured,thenthein-linefansystemwasturnedoffandthetopfloorallowedtotransferheatnaturally(Figure13).Thein-linefansystemdroppedthetimeconstantmeasuredbyroughly50%to160seconds(Figure13,'FanOn'),andthethermalmassofthesystemcanbeseenreleasingheatbackintothetopflooroncethefansystemwasturnedoff(Figure13,'FanSystemOff').Thisdemonstratesthatthein-linefansystemisabletooperatemuchbetterthannaturalheattransferprocessesandcompareswellwithstandardHVACresponsiveness.Thus,thein-linefansystemwouldbeexpectedtoreliablyprovideheatingandcoolinginthepresenceofsufficientnaturalheatsourcesandsinks.

FIGURE13RESULTSOFOPERATINGIN-LINEFANSYSTEM

Figure13demonstratesthebasicabilityofthefansystemtocontrolroomtemperatureinthephysicalprototypebydirectingairfromtheheatsink(thebottomfloorwithdryice)totheheatsource(thetopfloorwithheatedair)testedempiricallyintwomodes.(a)First,thehomewasheatedto35degreeandfirstallowedtocoolnaturally,andthenthefansystemturnedontoimprovetemperaturecontrol.(b)Secondandconversely,thehomewasagainheatedandthefansystemturnedontocoolthehome,thenthehomewasallowedtocoolnaturally.Thetimeconstantofthetemperatureresponse(measuredasthetimetoreach63%ofthesteadystatecondition)decreasedsignificantlybyhalfwhenthefansystemwasengaged.

SIMULATIONS–SIMULINKANDSOLIDWORKS

FIGURE14SOLIDWORKSMODELSIMULATIONS

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Theconvectiveflowmodelofafull-sizedhomewasdevelopedinordertodeterminetheflowcharacteristicsofastandardhomeandrationalizewhetherthein-linefansystemwassufficienttogeneratetherequiredinternalflowandachievethenecessaryenvironmentalconditions(Figure12).Itwasdeterminedthatafullscale10”fanwithstandardvolumetricflowrateswassufficienttogeneratecirculationinthehomeinwellunder30minutesbasedonthefan'sflowrateandthehouse'stotalvolume.Thiscouldbeachieveddespitetheeffectsofnaturallyoccurringconvectiveflowinducedbytemperaturegradientswithinthehome.TheSolidWorksmodelwasalsoscaledappropriatelyusingthismodelfromafullsizemodelwith8and9-footceilings(Figure13),toa1/20thscalemodelwith0.4ft.and0.45ft.ceilings(Figure14).

FIGURE15FULLSCALEHOME-SOLIDWORKSMODEL

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FIGURE16CUT-AWAYOFDUCTAT1/20OFSCALE

Thehousewasmodeledbasedonstandardmeasurementsofthemodernhome.Thisincludedwallthicknesses,ceilingheight,androomsizesforexample.Withanactualhouse,wecouldsimulateflowpatternsandthermaldistributionsusingSolidWorks.Thispreliminarytestingallowedustodeterminewhatdimensionswerefeasibleforourin-lineductingtohave.Thesimulationalsoshoweduswhatvelocitiesofairwecouldexpectwithinthehomewhilethesystemisrunning.Thiswasimportantsinceairflowsthataretoohighcancausediscomfortfortheresident,butairflowsthataretoolowdonotofferanycirculatory/airexchangeeffects.Thesimulationallowedustotweakourduct-openings,aswellastheorientationoftheduct'slocationinordertooptimizebothair-exchangeandair-velocityinthehome.Theresultswerepromisingaswecoulddemonstratethatthetopfloor'stemperaturecouldbedroppedby~8degreesCelsiusinlessthan25minuteswhenairispulledfromthebasement.Thissimulatedmodelwasaspringboardfromwhichwecouldcompleteadditionaltasksdowntheline.

Two'Simulink'-basedthermalmodelsofstandardAlbertahomes(onewithastandardHVACsystem,andonesupplementedwiththein-linefansystem)wereconstructedusingthetimeresponsivenessderivedfromthephysicalprototypeinordertodeterminetheenergyandcostsavingspotentialofthesystemfortypicalhomeownersinAlberta.Thetemperaturemodelsofbothsystemswerebasedonasinusoidaltemperatureinputwithanoffsetof16degreesCelsius(theaveragetemperatureforourbenchmarkmid-SummerdayinAlbertabasedondatafromRETScreen'shistoricaldatainAlbertain2014),a24-hourperiod,andpeak-to-peakamplitudeof20degreesCelsius.Bothhomemodelsconsistedofthermalmodelsofthetop,main,andbottomfloor(Figure17,middlegraphsofbothpanels),basedonthetemperatureinputs,athermostat/relaycontrolsystem,thehome/furnace/ACactingastheplantandthemainflooractingasthesystem.Temperatureswerereadusingideal

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thermocoupleswithnointernalfirstorderdynamics.Thestandardhomeoperatesnormally,providingheatintheeveningwhenthefloortemperaturedropsbelowthesetpoint,andairconditioningwhenitgoesabove(Figure17,leftpanel).Thetotalenergycostsforthestandardhomeusinganaturalgascostof$2.50permmBTUandanelectricitycostof$0.15/kWhtotalledapproximately$6.25/2daysoffunctioningnormally(equivalenttoroughly$1,000.00to$1,200.00forhomeheatingandcoolingenergyannually).

Thealternativemodelofthehomeincludedathermostatwhichwoulddecidewhentousethein-linefansystem,shuttingofftheexistingHVACsystemtodrawonlyonpoweravailablefromthenaturalheatsourceorsink,asrequiredifavailable.Atleast4degreesoftemperaturedifferenceisrequiredbetweenthesourceorsinkandthefloorwiththesettemperatureinordertodrivethetemperaturetoitssetpointinareasonableperiodoftime.Thetotalenergycostsforthealternativehomeusedthesamepowercostsasthestandardhome,totalingapproximately$4.10/2daysoffunctioningnormally(theequivalentofroughly$750.00-$850.00forhomeheatingandcoolingenergyannually).Additionally,therequiredairconditioningpowerwasalmostentirelyeliminatedinthisscenario.

Figure17showsresultsfromtheSimulink-basedmodelofastandardAlbertahomes(left)andahomewithanin-linefansystemsupplementingastandardHVACsystemoveratwo-dayperiod(right).Topgraphsshowtheon/offstateofthefurnace/ACforthetopfloorandbottomfloorflow.Middlegraphsshoweachfloor'stemperature(topfloorinred,mainflooringreen,basementfloorinblue).Bottomgraphsshowtheinputenergycosts(naturalgasinred,electricityinblue,andthetotalinblack).

PROTOTYPEDESIGNANDMANUFACTURING

Theinitialprototypedesignconsistedofa6ft.tall,6in.diameterductwithareversiblefanhousedinside.Thermocouplesweretobeplacedateachendoftheducttocapturetemperaturedataasairenteredandexitedtheduct.Acontrolsystemverysimilartotheoneactuallycreatedwouldreceivevoltagereadingsfromthermocouples,thenapplyavoltagetothereversiblefanmovetheairasneeded.Toproperlyscalethisprototype,itwassuggestedthatthe6in.fanbeoperatedatsuchaflowrateastokeeptheReynolds’snumberidenticaltothefull-scalesystem(10in.fan).Thispreliminaryprototypedesignwouldeffectivelyshowcasethecontrolsystemsincethetemperaturedatacollectedwouldresultinthefanmovinginadesireddirection.However,itwasdeterminedthatotherusefultestingdatamay

FIGURE17RESULTSFORSUPPLEMENTATIONOFANHVACSYSTEMWITHTHEIN-LINEFAN

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notbesuccessfullyrecoveredfromsuchamodel.Forthatreason,amoreholisticprototypewasconceptualizedandimplemented.

Itwasacknowledgedthatasuccessfulprototypewoulddisplaynotonlyeffectivecontrolsystemimplementation,butalsoeffectiveairflowandtemperaturedistributioncapabilities.Forthesereasons,theprototypeapproachchosenwastobeascaleddownversionofthehousesimulationbuiltinSolidWorks.Thisclosedsystemwouldallowairexchangetooccurandmeaningfultemperaturevaluestobecollected,whilebeinganaccuraterepresentationofthefullsizesystem.Aftercarefulconsiderationandplanning,thehouse-scalingfactorwasdeterminedtobe1:20;thismadetheprototype'ssizeroughly2ft.widex1.5ft.deepx2ft.tall.Sincetheprototypewasascaledreplicaofthesimulationmodel,datacollectedduringtestingcouldbedirectlycomparedwiththesimulationresults.

Theprototypeconsistsofthreestories,eachidenticaltotheSolidWorksmodel.Theinteriorwallsandstaircaseswereincludedtohelpreplicatetheexactflowdistributionsproducedinthesimulations.Allwalls,floors,andstairsweremadeof3/4in.Plexiglassincethismaterialwaslightweightandallowedustoviewtheinsideofthehouse.Thisfeaturecomesinhandywhentryingtovisualizetheairflowwiththeassistanceofdryice.Also,thePlexiglascreatesamoreatheisticallypleasingprototypefortheaudience,andmakesexplainingthefunctionalityoftheprototypeeasier.Tosimulatetheductairflow,2in.PVCpipingconnectsthetopandbottomfloorswiththeassistanceoftwo90-degreeelbows.Twosmallfansarelocatedhalfwayuptheductandareplacedbacktobacktosimulatereversibleflow.Initiallyonlyonefanwastobeused,andreversibleflowtobesimulatedbyinvertingthevoltagesonthefan.However,thefanburnedoutafterrunningintheoppositedirectionsothisoptionwaseliminated.Thefansareheldin-linewiththeductusingtwocustommadeadapters.Theadaptershouseandsandwichthefansbacktoback,andaremechanicallymatedthroughtheuseoffournutsandbolts.

Mountedtothefanhousingisthecontrolsystem.TheheartofthesystemistheaforementionedArduinoUnoboard.TemperaturesensorsoneachlevelrundirectlytotheArduinoinputpins,whereMatlablogicinterpretstheinputvoltagesandoutputsadesiredvoltagetotherequiredfan.Tomaketheprototypemorerealistic,thermalmasseswereaddedonthetopandbottomfloors.Thesemasses(sheetsofmarbletile)absorbenergysimilartofurnitureandotherhouseholdbelongings.Thisenergycanthenbereleasedtothesurroundingswhentemperatureschangeinthevicinity.Alltogethertheprototypesuccessfullyredistributesairwithinthehomewhenatemperaturesinkandtemperaturesourcearepresent.

PROTOTYPETESTING

Withafullyfunctionalprototype,thenextstepwastestingthemodel.Acrucialaspecttotestingthein-linefansystemwascreatingalargetemperaturedifferencebetweenthetopfloorandthebottomfloor.Thisneededtobedonetosimulatethenaturaltemperaturegradientthatformsineveryhome;thewarmairtrappedupstairsandthecoolairresidinginthebasement.Thelargestproblemwasfiguringoutexactlyhowtocreatesuchalargetemperaturedifferenceinsuchasmallspace.Theteamsuggestedperhapsconductivelyheatingthetopfloorwithaheatingpad,andconvectivelycoolingthebottomfloorwithcoolair.Thiswasagoodstartingpoint,butitwaseasytoseethetimerequiredforbothoftheseprocessestoeffectivelyaddandremoveenergyfromthesystemwouldtakefartoolong.Thenextlogicalstepwastoblowwarmairintothetopfloorandtosubmergethebasementintoanicebath.Boththeseapproachessignificantlyreducedthetimeittooktoincreasetheupstairstemperatureandto

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decreasethebasementtemperature.However,blowingwarmairdirectlyintothesystemwasmuchfasteratreachingthedesiredtopfloortemperatureincomparisontothetimeittooktheicebathtoreachthedesiredbasementtemperature.Tobeprecise,ittookmerely45secondstowarmtheupstairsfloorto35degreeswhereasittookcloseto15minutesfortheicebathtoreducethebasementto10degrees.

Itwasn’tuntildryicewaspurchasedtoshowflowdistribution,thatitscoolingpotentialwasrealized.Theendothermicreactionabsorbedenergyveryquicklyfromthebasementenvironment.Usingroughly100gofdryicedroppedthetemperaturedownto10degreesinminutesandkeptitsteadythroughoutthetesting.Withtheabilitytoestablishalargetemperaturedifferenceeasily,multipletestscouldberunefficientlyandeffectively.Tophysicallytestthesystem,twotrialswererun.First,theupstairsfloorwasheatedto35degrees,thebasementwascooledto10degreesandthesystemwaslefttoredistributethetemperaturedifferenceonitsown.Temperaturedatawascollectedevery30secondsfromboththetopfloorthermocoupleaswellasthebottom.Ittookthesystem12minutestoreach23degreesupstairs,afterwhichthetemperatureplateaued.Oncethisplateauwasreached,thesystemwasturnedontoseeifithadanyadverseeffect.Withthesystemturnedon,thetopfloortemperatureimmediatelybegantodecreasewhilethebottomfloorbegantoincreaseshowingacleartransferofenergyoccurring.Afterthistrial,thetopandbottomfloorswereonceagainsetto35degreesand10degreesrespectively,butthistimethefanwasrunimmediately.Withthefandrawingcoolairfromthebasementupstairs,thetemperaturereached23degreesinonly5minutes.Thiswasadramaticdifferenceincomparisontothehouseattemptingtoreachequilibriumonitsown.Oncethe23-degreetemperaturewasachieved,thefanwasturnedofftoseewhatwouldhappen.Theupstairstemperatureimmediatelybegantoincreasewhilethebasementbegantodecreaseduetothethermalmassesreleasing/absorbingenergy.

Thesetestswererunatthemaximumfanspeedof8cfmtodemonstrateproofofconcept.However,inthenexttrial,thefanwasrunatitsminimumspeedof2cfm.Atthisflowrate,thetemperatureredistributionoccurredjustasquicklyaswhenthefanwasrunat8cfm.Thisdemonstratesthatathighflowratevalues,coolingcapabilitybecomesindependentofflowrate.Ideallythesetestswouldberunatmuchlowerflowratestomorecloselyreplicatethevolumeofairredistributedinanactualhome,butflowratesthatlowarenotpossibletoachieve.Withaflowrateofapproximately400cfmfoundintheactualhome,andruninthesimulation,wewouldbeleftwithaflowrateof0.05cfmafterapplyingour1:20scaleonallthreedimensionsoftheprototype.

RAINWATERMANAGEMENT

SENSORCALIBRATION

Oneofthemostcrucialcomponentstowardshavingasystemthatworkseffectivelyandreliablyistheinstallationofthemoisturesensorunderthesoil.Afterperformingplentyofproductresearch,weconsideredcheapsensorsandexpensivesensors.Thedrawbacktohavingacheapsensorinstalledonourprototypewouldhavetodealwithlargeerrortolerancesanddatathatcontainedalargeamountofnoise.Withamoreexpensivesensor,thedatareceivedwouldbecleanandextremelyeasytouseandtune.Forthepurposeofourprototype,wedidnotneedmanyofthefeaturesthatarereceivedwith

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moreexpensivesensors,suchastemperatureandhumidityreadings.Afterconsideration,wesettledontheEC-5sensorfromdecagondevices(DecagonDevices,2015),whichismodestlypriced.Thisisananalog,volumetricwatercontent(VWC)sensorthatusesthedielectricconstantofthesensedmediausingcapacitanceandfrequencydomaintechnology.Itallowsfortheaccuratemeasurementofallsaturatedsoilsbetween40-60%water.

FIGURE18PICTUREOFTHEEC-5SENSOR(DECAGONDEVICES,2015)

VOLUMETRICWATERCONTENT

Thevolumetricwatercontentinamaterialistheamountofwaterwithinthehostmaterial.Inourcase,thehostmaterialispottingsoil.Itisdescribedmathematicallybelow(Wikipedia,2016).

!"# = !!!!"#

Where!!isthevolumeofwaterand!!"# isequaltothetotalvolumeofthewetmaterial.Thewetvolumecanbeexpandedas,!!"# = !! + !! + !!.Where!!isthevolumeofthehostmaterialand!!isthevolumeofair.

EQUATIONS

Forappropriatecalibrationofthesensor,youmustchooseanequationdependingontwoimportantinputvariables.First,thesoiltypeyouareusingandsecond,theinputexcitationvoltageofthesensordependingonyoursensorpoweringmethod.Inourapplication,weusepottingsoilforthepurposesofprototypetestinganddesignfairviewing.Thesecondinput,whichisexcitationvoltage,is3.3Vpowered

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directlyfromthebreadboardconnectedtotheWandboard.Thefollowingistheequationweusedforthecontrolsystem;weobtaineditdirectlyfromDecagonDevices(DecagonDevices,2015)forpottingsoilanda3.3Vexcitationvoltage:

!"# = 0.00992 ∗!!!"#!$% − 0.45

TheEC-5sensorislesssensitivetovariationintextureandelectricalconductivitythanothermoisturesensorsbecauseitrunsalowmeasurementtimeof10ms.Thisisbeneficialforeasyapplicationtomanymineralsoils,withthecalibrationequationsnotchangingsubstantiallyfromonesoiltoanother.Unfortunately,anappropriatecalibrationequationmustbeobtainedfortheexcitationvoltageused,sincethiscancausealotofvariation.Forinstance,thefollowingistheequationforpottingsoilatanexcitationvoltageof2.5V:

!"# = 0.00211 ∗!!!"#!$% − 0.675

Testswereruninordertodeterminethedifferencebetweentheseequations.Wewantedtoensurethatthedatareceivedandtransformedfromtheseequationswasclearlybetterandmorereliable.Thefollowinggraphdemonstratesthistest:

FIGURE19SENSORCALIBRATIONEQUATIONSCOMPARED

Asseenfromthefigure,thedatastreamsfromtheappropriate3.3Vexcitationvoltageequation(foundinpurpleandyellow)haveasmallerstandarddeviationof1.06onaverage.Thestandarddeviationfrom

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the2.5Vequationsyieldedanaveragestandarddeviationof1.39,whichis30%higherthantheappropriateequation.Withtheuseofanappropriateequation,thesesensorscanobtainanadvertised0.25%resolution.Onemustensurethattheappropriateequationisusedaccordingtotheexcitationvoltage,withalotofflexibilitylyingamongstthetypeofsoilused.

CONSTANTSANDTHRESHOLDS

Inordertoformulateacontrolsystemlogicthatisreliableandeffective,wemustbaseitfromconfidenceinwateringconstantsandthresholdvalues.Thesevaluesdescribeapointinwhichwedeemthesoiltobeadequatelywatered;thisisbasedontestingandresearchedvalues.Below,thereisafiguredescribinginputdatafromasensorwhileaplantiswatered.

FIGURE20SENSORTHRESHOLD-WATERINGSOIL

Note:Thedataforthisfigurewasrecordedwiththe2.5Vexcitationvoltageequation.

Inthefigureyouwillfindthethresholdvalue(horizontalline)withdatasectionsaboveitandbelowit.Thedatafoundfarabovethelineisthesensorindrysoil.Whenthebluelinedropsbelowthethresholdvalue,youcanseethatthedatabecomesscatteredforapproximately1secondbeforeitsettlesatavaluebelowthethreshold.Thesoilisnowconsideredadequatelywatered.

Withtheinclusionoftheappropriatecalibrationequationasstatedabove,thefinalthresholdvalueforthepottingsoilusedwas430.Onemightexpectthatasthesoiliswateredthevaluewouldincrease,butinreality,therelationshipisreversed.Asthesoiliswatered,thevaluesofincomingdatawilldrop.Thisrelationshipisstrictlyareflectionofthemethodonwhichthesesensorsfunction,andthatisthedielectricconstantofthemeasuredmediausingcapacitanceandfrequencydomaintechnology.

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NOISEFILTERING

Duringtesting,therewasnoisethathadtobedealtwith.Thegraphbelowdepictsthisnoiseanditsinherentproblemsduringimplementationinourcontrolsystem.

FIGURE21NOISEFOUNDINSENSOR2

Theorangelineshowsthattheincomingdatafluctuatesbetweentwomeanswhilethebluelinesitsconstantlyononemean.Thisfluctuationwasofgreatsurpriseintestingbecausebothsensorsareinthesamesoilcup.Aftermuchinvestigation,thefluctuationsweretiedtoanairpocketinthesoilbeingsituatedbesidethesensor.Methodsonhowtopreventthisfromhappeningaredescribedinthefollowingsection.

SENSORPLACEMENT&BESTPRACTICES

InordertoobtainconsistentdatafromtheEC-5sensor,timemustbetakentoensurethatitisinstalledcorrectly.Toretrievethebestdatapossible,itisbesttomaximizethecontactbetweenthesensorandthesoil(Devices,2015).Notonlyshouldtheprongsofthesensorbeburied,butalsotheblackovermoulding.Themostimportantaspectofinstallingthesensoristoensurethattherearenoairgapsinthesoilaroundthesensor.Topreventthis,wefoundthatiswasmosteffectivepressdownthesoilthoroughlyaroundthesensorafterthesensoriscompletelysubmergedinthesoil.Itisimportanttobeverygentlewiththeprongsonthesensortokeepthemintact,aswellasnottobendtheblackovermouldingtopreventanyinternalconnectionfailures.

SENSORERROR

Whenmoisturevalueswereretrievedfromtwosensorsinthesamemoisturecontent,therewasalwaysdiscrepancyamongmeanmoisturevalues.SinceDecagonguaranteescertainaccuracyinitssensors

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(DecagonDevices,2015),thediscrepancymustresidewithinthebuildofourprototype.Thedatareceivedfromthesensorsistransferredthroughsolderedconnections.Underthebudgetwewereunder,thesolderedconnectionsweredonein-house.Sincetherewasnowaytoguaranteecompleteuniformityintheseconnectionswiththeequipmentwehadavailable,thiserrormustresidewithinthispartoftheprototype.Thefigurebelowdemonstratesthedifferenceamongincomingdatameans.

FIGURE22DISCREPANCYAMONGSENSORMEANS

Note:Thedataforthisfigurewasrecordedwiththe2.5Vexcitationvoltageequation.Thesediscrepancieswerestillfoundwiththeproper3.3Vequation.

Withtheapplicationsofourprototype,thesediscrepancieswerenotdetrimentaltothelogicofourfinalcontrolsystem.Thediscrepancyusuallysataround5unitsofvolumetricwatercontent,whichtranslatestoapproximatelya1%difference.Decagonguaranteesanerrorof0.25%fromitssensors(DecagonDevices,2015),thereforeatleast0.75%ofthiserrorresideswithinourprototypesetup.

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FIGURE23LOCATIONOFSOLDEREDCONNECTIONS

DATAINTERPRETATIONS

Adifficulttaskofanyprojectistotakeindatafromapurchaseddeviceandtranslateitintoaformthatisusefultotheproduct.Inourcase,theEC-5sensorproduceddatathatwasinitiallynoisefilledwithvaluesthatseeminglyhadnorelationtounitsofvolumetricwatercontent.Asdiscussedinprevioussections,weappliedappropriatecalibrationequationsandderivedbestpracticesforoptimalsensorplacement.Thisresultedindatathatwasfarmorereliableandmeaningful.Thissectionaimstooutlinethetestsweusedtodevelopconfidenceinourdataaswellasoutlineimportantsensorcharacteristics.

TESTTYPES

InordertoensurethattheEC-5sensorswereworkingtotheirfullpotentialinourproduct,werandifferentteststomitigatetheeffectofhumanerrorsandprototypebuildinconsistencies.Theinitialtestweraninvolvedfillingupcupswithequalamountsofsoilandplacingtwosensorswithineachconsecutivecup.Thepurposeofdoingthiswastoensurethateachsensorwasrecordingasimilarmeanmoisturelevel.Thefollowingfigureshowsoneofthesetests,wherethesensorsareplacedinthecupat

Locationofsolderedconnections.

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thebeginning.

FIGURE24SENSORCALIBRATIONTEST-2SENSORSINONECUP

Thesecondtestweranwaswithbothsensorsinthesamecupagain.Duringthesecondtesttypeweaddedasmallamountofwaterinanattempttorecordatrendofincreasingdatavalues.Theresultsofoneofthesetestscanbeseeninthefollowingfigure.

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FIGURE25SENSORCALIBRATIONTEST–2SENSORSINONECUPWITHWATERADDED

Itshouldbenotedthatthedownwardtrendoftheresultingdatawasnotassignificantaswewouldhaveliked.SincethetestwasrunintheearlystagesofhavingtheEC-5sensor,wehadnotyetdevelopedbestpracticesfortheirinstallation.Oncethesebestpracticeswerediscovered,thetrendwasmuchmoredrasticandreflectedmuchmoreusabledata.Thedatawasfurthertunedwiththeimplementationofthecorrectcalibrationequation.

SYSTEMPARAMETERS

Aftertesting,importantsystemparameterswererealized.Inanyelectromechanicalsystem,thephysicalnatureoftheseparametersmustbedeterminedandaccommodatedinthedesignofthecontrolsystem.Inoursystem,theseparametersrelatetoeachotherthroughtheinputofsensorvalueandtheoutputofpumppowerandvalveorientation.Themostimportantaspecttokeepinmindisthesettlingtime,whichisthetimeistakesforasystemtosettleclosetoitssteadystatevalue.Withoutbeingawareofsettlingtime,oursystemwillcorrespondinglybeoverwateredwhichwillresultinwastage.Ifwateriswasted,itwilldefeatthefundamentalpurposeofthesystem!

Throughexperimentation,thesettlingtimewasdeterminedtobeapproximately30seconds.Thereasonitissolongisduetothesoil,andthetimeittakesforfreshlyappliedwatertosoakintoit.Oncethewaterhassoakedin,thatisthemoisturevalueweareinterestedinmonitoringwhilethecontrolsystemisrunning.Anotherimportantsystemparameterinoursystemistherisetime,whichisthetimeistakesforasystemtorisefrom10%to90%ofitssteadystatevalue.Inoursystemthisdirectlyappliestotherateatwhichwaterisappliedtothesoil.Thisrateistunedbywaterdivertingvalvesandpowertothepump.Thisisadifficultparametertotuneperfectlyduetotheinconsistencieswiththetimeittakes

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fordifferentsoildensitiestobecomesaturatedwithwater.Overthecourseofourtesting,wewerenotabletorunenoughteststoinstiladequateconfidencewithinourselvestosettleonanexactrisetime.Theparametersthatadjustrisetimecanbesolidifiedafterrunningmoretests.

PROTOTYPEDEMONSTRATIONS

Forpurposesofdemonstratingthesystematthedesignfair,weimplementedacontrollogicthatcommunicatedthefundamentaldecisionmakingpowerofthesysteminthesimplestwaypossible.Asseeninthefigurebelow,theprototypewassetupwithtwosoilcupseachhavingonesensorplacedwithinthemandanirrigationlineplacedabovethem.Thevalvescontrolledtheirrigationlinesindependently.

FIGURE26PROTOTYPEATDESIGNFAIR

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Differentdemonstrationswererunatthedesignfairtocommunicatethatthesystemwasintelligentenoughtodecidewhich‘zone’orcupneededwatering,andforhowlong.Themostcommondemonstrationwastheplacementoftwosoilcupswithslightlydifferentmoisturelevels.Duringthedemonstration,bothcupswouldinitiallybecomewateredbythepumpbuttheywouldbothpassthethresholdmoisturevaluesatadifferenttime.Thiscommunicatedhoweach‘zone’isindependentofoneanother.

Otherrunsweresetuptodemonstratethatthesystemcouldimmediatelyrecognizeaproperlywateredzone.Thiswasdonebyplacingasensorinapreviouslywateredcup,whichresultedinthesystemhavingknowledgeofthewateredstatusandsimplymonitoringituntilthesoildriedup.Overall,thedesignfairdemonstrationsworkedeffectivelyandcommunicatedthedesignconceptwell.

PROTOTYPEROADBLOCKS

Aswithanydesignproject,thereareinevitableproblemsanddesignchallengesthatyoumustovercome.Withinourproject,thereweresomethatwerehardertosolvethanothers.Fortunately,wewereabletosolvealltheproblemswefaced,allowingustodeliverallaspectsoftheinitialscopeoftheproject.Belowthereisanoutlineoftheproblemsweencountered.

VALVEOPENINGANDCLOSING

WiththedecisiontomoveforwardwiththeWandboardmicrocontroller,welimitedourselvestocertainpowerlevels.Thesepowerlevelswereneededtoactuatethevalvesthatcontrolflowtodifferentzonesinoursystem.Inordertogreatlysimplifythesystem,welookedforvalvesthatcouldbeactuatedbya5vsourcebuiltdirectlyontotheboard.Thisremovedtheneedforexternalpowersourcesandmoreelectricalswitchesaddedtothephysicalcontrolcircuit.

TheonlyvalveswewereabletofindwereonesavailablethroughAliExpress(AliExpress,2016).Thesevalvesseemedverypromisinguntiltheyarrived.Wequicklydiscoveredthattheyrequiredapositivevoltagepulsetoopen,andanegativevoltagepulsetoclose.Thisisquitedifferentfromourexpectationofhavingtosimplyapplyconstantpowertoopenthevalve.Thisproblemwasoneofthelargestinourproject,andwaseventuallysolvedusingacombinationofelectricalswitches(transistors)aswellasmechanicalrelaysthathadtwoinputsaswellasoutputs.Asmentioned,theproblemwassolvedusingtheresourceswehadaccesstoo,butinfuturerevisionsofthisproduct,avalveshouldbechosenwithmorestandardizedcontrollogic.

CODINGLANGUAGEDISCREPANCIES

Sincethisproduct’sprimarysellingfeatureisitsabilitytorunautonomously,weneededtocodethecontrolsysteminalanguagethatisnotveryCPUintensive.ThisimmediatelyclosedoutthepossibilityofitbeingcodedingraphicalcodinglanguagessuchasLabvieworMatlab’sSimulink.Inlightofthis,ourteamdecidedtocodeinPython,becauseofitslargefunctionlibrary,simplemathematicaloperationsandbecauseofitsquicklearningcurve.

SincetheoperatingsystemweloadedontotheWandboardisUNIXbased,theeasiestwaytoaccessincomingdatafromoursystemwaswithsimpleBashcommands.Unfortunately,Python’sabilitytoreadandwritedatathroughtheuseofBashcommandsisanythingbutsimpleforagroupofmechanicalengineers.Throughtheuseofbackgroundresearch,wewereabletomakethecodereadandwriteto

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oursystemusingPython’sOpen/Write/Closecommands.ThisroadblockmadeourgroupquestionthedecisiontocodeinPythonmanytimes,butitwaseventuallysolvedwiththeuseofthecorrectPythonfunctions.

PUMPFAILURE

Asdiscussedinanearliersection,thedesignfairdemonstrationswereperformedinawaytoshowasmanypeopleaspossibleoursystemworking.Withthisconstantresettingofthecontrolsystem,thepumpwasforcedtopowercyclerepeatedlyforhoursatatime.Withthispowercycling,thepump’sinternaloverheatswitchwastriggeredandthepumpfailedtoproducesufficientpressureforoursystemcorrectly.Fortunately,thisfailureoccurredwithahalfanhourleftinthefair.

Thisfailurewasnotedandanalyzedasapotentiallong-termissueforoursystem.Weconcludedthatitwouldnotbeaproblemforthissystemifitweredeployedtothefield.Thereasonbeingisthatthepumpwouldneverhavetopowercyclerepeatedlyinthesettingofagarden.Itwouldbepoweredononceortwiceadaytoprovidethesufficientamountofwaterfortherequiredzones.Oncethezoneshavebeensufficientlywatered,thepumpwouldlayinanidlestatewaitingforthesoiltodryoutonceagain.Asmentioned,thisfailurewasnotoverlyconcerninginthecontextofactualproductfunctionality.Inordertoensurethehighestlevelofconfidence,wewouldimplementapumpthatwehavetestedextensivelyandweknowcanhandlealloperatingmodesofthesystem.

PRESSUREISSUES

Thepumpusedinoursystemworkedverywellfortheapplicationofthisprototype(asidefromtheproblemmentionedabove).Theonlydrawbackwithitsapplicationtoourcontrolsystemwasitslackofpowervariability.Whenthepumpisconnectedtoa110VACwalloutletitwouldsimplyturnonandprovideitsspecifiedoperatingpressure.Inthecontextofthedripirrigationtubingusedinourprototype,andpotentiallywiththeproduct’sfieldimplementation,thispressureissimplytoomuch.Itprovidesfartoomuchwaterintoshortofatime.

Thesolutiontothisproblemtookplaceintwostages.Thefirststagewaswiththeacquisitionofapressurereducerthatprovidedaconstantoutputpressureequaltothestandardoperatingpressurefordripirrigation(25PSI,(Smeal),(TheHomeDepot,2016)).Withthisaddition,thewaterreceivedattheoutletofthedripirrigationlineswasmuchsmallerandfareasiertoworkwithduringthecodingofourcontrolsystem.Adrawbacktothisadditionwasthatthebackpressurenowplacedonthepumpwasmorethantheratedamountforthegasketsealingtheplatearoundthepumpsimpeller,whicheventuallycausedacatastrophicleak.Afterthegasketwasreinstalled,awaterdiverterwasaddedtotheoutletofthepump,whichallowedthemajorityofthewatertoberecycledtothewaterholdingbin.Thewaterdiverterhadbuiltinvalves,whichallowedforeasytuningofvolumetricflowratesineachdirection(TheHomeDepot,2016)(i.e.eithertothedripirrigationlinesorbacktotheholdingtank).Withtheadditionofboththepressurereducerandthewaterdiverter,wewereabletoobtainthecorrectoperatingpressureforthesystemwhilealsopreventingpumpleaks.

COMMERCIALIZATIONOFTHEPRODUCT

Movingforward,thisproductwouldbemarketedtowardsindividualslookingforanautonomouswaytoensureahealthylawnwhilealsosavingwater.Inordertogettheproducttothiscommercializedlevel,wemustelicitthehelpofelectricalengineerswhocanredesignthephysicalnatureofthecontrol

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systemontoaprintedcircuitboardaswellaswriterobustfirmwarelogicforembeddedoperationsinthemicrocontroller.Aftertheprintedcircuitboardisconstructed,theuserwouldsimplyconnecttherequiredamountofsensorsfortheirapplicationandinterfacewithapumpandvalves.

Inordertomakethisproductuserinstallable,aswellasuserconfigurable,wewouldworktoeitherintegrateamobileapplicationorwebsitethateasilyconnectsthemtoimportantsystemparameters.Thebenefittomakingthesystemsoconfigurableisthatisallowstheusertoeasilychangezonerequirementsandwateringguidelines.Withabuiltindatabaseofwateringrequirementsformanycommonplants,thesystemwouldhaveexistingknowledgeofall-importantparameters.Thismakessetuptimeverysmallwhilealsoensuringstressfreesystemchangesinthefuture.

SCENARIOMODELING

InordertoderiveanestimateofthepotentialGHGemissionssavingsaffordedbythereasonably-expecteddeploymentofthein-linefanandrainwatermanagementsystems,wemodelledtheenvironmentalimpactsexpectedundertwoseparatescenarios:1)thebusiness-as-usual(BAU)scenariobasedontheemissionsofastandardAlbertahome,and2)thealternativescenariobasedonanAlbertahomesupplementedwiththein-linefansystemortherainwatermanagementsystem.Thegrowthofsingle-detachedhomesinAlbertawasestimatedusingtheCanESSmodelforaenergy-basedeconomyassumingalow-oil-sandsgrowthscenario.Ofthesehomes,thenumberofexpectedsingledetachedhomeseachyearbetween10and30yearsoldwasestimated.Weassumedourproductcouldbedeployedtoamaximumof5%ofnewlyavailablesingle-detachedhomesoftherequiredagerangeeachyearwithintenyearsofstartingupaprospectivebusinesstosellthesystem.

ThegrowthinthenumberofresidenceinAlbertafortheBAUscenario(Figure20a–bluearea)isexpectedgrowbutdeclineintherateofgrowthduetothedeclineinoilsandseconomicactivitypredictedbythelowoilsandsgrowth.ThisscenarioassumesanddemonstratesthatoilsandseconomicactivityisasignificantdriverofimmigrationandresidencegrowththroughoutAlberta.ThegreenhousegasemissionsestimatedforallAlbertaresidencesunderthisscenario(Figure20b–reddashedline)isthesumoftheemissionsfromconsumingnaturalgasinhighefficiencyfurnaces,andthosederivedfromtheAlbertaelectricalgridbasedondemandforelectricitypredictedfortypicalACunits(200BTUspersquaremeter,and0.15W/BTUpowerrequiredforheatclearance)standardizedtotheaverageexpectedhomeareaeachyear.ThewaterusageestimatedforallAlbertaresidences(Figure20c–reddashedline)istheexpectedaverageAlbertaresidentialoutdoorwaterusagemultipliedbythetotalnumberofresidenceswithlawns,whichwouldexperiencesuchdemand.

Inordertoconstructthealternativemodelanumberofcriticalassumptionsconcerningthedeploymentandintegrationofthein-linefanandwatermanagementsystemswererequired.First,thepotentialutilizationofthein-linefansystemwasestimatedbasedontheresultsfromtheSimulinkmodels.Althoughthemodelspredictedapotential1/3utilizationfactorforthein-linefan,aconservativeestimateof1/4wasusedtoaccountfornon-idealclimateconditions.TheACadoptionratewasconsideredstaticforAlbertathrough2060andwassetat27%(REFERENCE?).Theadoptionofnaturalgas-basedheatinginhomesinAlbertawasalsoassumedtobestaticanduniversalforallhometypes,andwassetthrough2060to90%.Theaverageefficiencyofthesefurnaceswasestimatedat90%(asmustareeitherhighormediumefficiencyat95%and85%,respectively.Theutilizationoftherainwatermanagementsystemwasestimatedat90%ascapacity-basedcalculationsdemonstratedthatasuitably

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constructedrainwatercollectionsystemhadthepotentialtooffsetnearlyallofthehome'swaterdemand.

Giventheseassumptions,weestimatedthatwithin20yearsofdeployment(by2037),thein-linefansystemcouldcutemissionsfromAlbertahomesby16MtCO2eperyear(foracumulativetotalof157MtCO2e),andtherainwatermanagementsystemcouldlowerAlbertawaterusageby11millionm3peryear(foracumulativetotalof26millionm3).Thein-linefansystemisparticularlyusefulforavoidingAC-derivedemissionsduringthesummermonths,asourSimulinkmodelsuggestedthatarelativelycoolbasementfloorhasthepotentialtosufficientlycoolahomeandalmostcompletelydisplaceACusage.Thisisparticularbeneficialasairconditioningreliesonrelativelycarbon-intenseelectricityfromtheAlbertagrid.TheAlbertagridreliesoncoal-basedpowerfornearlyhalfofalldemandgenerationwhichemits1020kgCO2e/kWh,whereasnaturalgasemitsapproximately400kgCO2e/kWh.However,ascanbeseeninFigure20b,thecarbonfootprintofthegridisexpectedtodeclinerapidlythroughto2050duetothegradualretirementofcoal-firedpowerplantsinAlbertaandtheirreplacementwithacombinationofnaturalgas-basedpowerandalternativepowergenerationsourcessuchaswindandsolarphotovoltaic.

TherainwatermanagementsystemhasthepotentialtobeaveryeffectivetoolinmitigatingwaterusageinAlberta.Someestimatessuggestthatsimplyapplyingawatermetertoahomecanreducetheburdenonwatertreatmentfacilitiesbyreducinghomewaterconsumptionbyupto50%.Thiscurrentsystemisabletocompletelydisplaceahome'sdemandfortreatedwaterforoutdoorwateruse,offeringtofurthersuppresstotaldemand.ThemainbarriertoincreasingthetotalresidentialwaterusageseeninFigure20cistheadoptionofthesystembyconsumers.

Figure25illustratestheprojecteddeploymenttosingle-detachedhomesinAlbertabeginningin2016andprojectedto2060.b)Within20years,thepassiveheatingandcoolingsystemcouldcutemissionsby16MtCO2-eqannually(157MtCO2-eqcumulative),whilec)therainwatermanagementsystemcouldlowerAlbertawaterusageby11millionm3annually(26millionm3cumulative).

FIGURE27PROJECTEDDEPLOYMENTOFSYSTEMS

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RECOMMENDATIONS

IN-LINEFAN

Recommendationsforthefuturedevelopmentoftheinlinefansystemarebasedonthecurrentresultsandbestunderstandingofthesystemandwillbebrokendowninto3majorcategories:

1) Recommendationsforadditionalphysicalandcomputermodeltesting2) Marketanalysisanddeploymentstrategies3) Nearterm(10year)potentialandscheduleforcontinuedproductdevelopment.

TESTINGRECOMMENDATIONS

Forfurtherengineeringdesignanalysisandtesting,werecommend:1)completephysicaltestingoftheprototypeinconditionssimilartotheextremeseason(winterandsummer),2)testingthecapacitytocontroltheremainingfloorsofthemodelhome,3)developingamethodtooptimizethecontrolsystemforavarietyofdifferenthomeconfigurations,and4)developingavarietyofrepresentativehometypesforsimulationinSimulink.

First,completingasecondstageofphysicaltestingofthemodeltobettercharacterizeitsperformanceindifferentphysically-simulatedenvironmentalconditionscouldhelptobetterunderstandtheparticularadvantagesthesystemoffersindifferentseasons.While‘summercondition’testingindicatedthattheairconditioningsystemsthatarestandardinroughly27%ofhomescouldbealmostentirelyoffset,itwouldbeinterestingtoknowhowthesystemperformsinwinterconditions.Theseresultscouldhelpinformadeploymentstrategy.Forinstance,iftheairconditioningfunctionappealstomanyhomeowners,thiscouldencourageearlyadoptionandcouldbestrategicallypursuedinordertogaininsightintothefunctionofthesysteminmanyhomes.Next,testingofthemodelonthemainandbasementfloorsareclearlyessentialinordertoensurethattheproof-of-conceptresultsaregeneralizableacrosstheentirestandardhome.

AgeneralizedmethodforoptimizingthecontrolsystemsettingsinordertoreducetheHVACenergyusageofabroadvarietyofAlbertahomeswouldbeanessentialsteptodecreasingengineeringcostsinfuture.Ashasbeenstatedpreviously,theengineeringcostsforsuchaprojectareexpectedtoberelativelyhighduetothecustomizednatureoftheretrofit.Reducingthiscostmayhelptomitigateaprimarybarriertoentryforconsumers.Thiswouldalsopermitourgrouptounderstandthepotentialofthistechnologywhendeployedtoabroadervarietyofhomes.Finally,thesedatacouldhelpustodevelopadditional‘non-standard’thermalmodelsofhomestodeterminetheirsuitabilityforsystemdeployment.

MARKETANDDEPLOYMENTRECOMMENDATIONS

Inordertobetterappealtoabroaderconsumerbaseandtounderstandthepotentialimpactofthesystemonenvironmentalimpacts,werecommend:1)conductingbriefsurveystoassesspotentialconsumers’willingnesstopayforasystemsuchasthein-linefanbasedonperception,cost,environmentalbenefitsandpotentialgovernmentsubsidies,2)marketingthesystemasatoolforimprovedairconditioning,and3)establishingasupplychainforthecriticalcomponents.

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Consumersurveyswouldbeessentialinallowingustostrategicallymarketoursystemtotheconsumersmostlikelytobewillingtopurchase.Itwouldalsogiveinsightintowhatconsumersfeelismostattractiveaboutoursystem(environmentalwell-being,costsavings,etc.)whichwillhelpustodirectourtechnicaltestingeffortstowardssolutionswhichwouldofferthegreatestappealtothesemarkets.Forinstance,testingindicatesthatthissystemmayuniquelybeabletooffsetaverylargeproportionofhomecoolingneeds.Ifthisprovedtobeanattractivefeaturetoconsumers,wecouldstrategicallypursuegainsincoolingpowerandperformancefirstinordergainagreatermarketshareearlier.Finally,thepursuitofagreatermarketsharerequiresthatasupplychainfortherequiredpartsformthemicrocontrollerstothestandardductingandwiringbeestablished.Thefundamentalabilitytodeploythesystemondemandtowaitingconsumersiscriticaltotheearlysuccessofthissystem.Theearlierthesuccessisinproductdeployment,thegreaterthereductionsinenvironmentalimpacts,whichbenefitseveryone.

NEARTERMSCHEDULERECOMMENDATIONS

Apredictionofthescheduleforpotentialneartermdeploymentisusefulforpredictingincomeandtoencouragethetimelycompletionofengineeringtasks.Assuch,werecommend:1)establishingafinalfullscaleprototypewhichcanbedeployedtoanumberofhomestocollectrelevantperformancedatawithinthefirstyear,2)basedonmarketdata,seekoutthebroadestpossibleconsumerbaseofpeoplewillingtodeploythesystemintheirhomeswithinthefirst5years,and3)attempttomarkettheearlysuccessesandbenefitsofoursystemtoabroaderconsumerbasewithinthefirst10years.

RAINWATERMANAGEMENT

Basedontheresultsobtainedfromourprototypeandtheresearchputintoourproject,thefollowingrecommendationsweredevisedinordertoprogressthisproject’sfuturedevelopmentintoaneventuallymarketableproduct.

TESTINGRECOMMENDATIONS

Inordertoimproveontheprototypescurrentsuccessfurthertestingwillberequiredsothatahigherlevelofeffectivenesscanbeobtained.Suchtestingincludes1)furthertestingofthesensorsaccuracywithreadingvolumetricwatercontent,2)testingthesystemsperformancewithdifferentsoilconditions,3)testsystemsabilitytointerpretdatafromseveralsensorsinfieldapplications.

Currentlyoursystemisabletoadequatelycontrolthedistributionofwaterbetweentwozonesofthesamesoiltype,arelativelysimpleapplication.Moreintensivetestswiththedataobtainedfromthesensorscouldpotentiallyimprovetheaccuracyofthesystembytweakingtheequationsusedforinterpretingthedata.Also,testingthesensorsindifferentsoilconditionswouldestablishtheparametersnecessaryforproperlycalibratingthesensorsindifferentsoiltypes.Accountingforadelayinthetimeittakesforthewatertoreachthesensordependingonthesoilsporosityisanadditionalrequiredexperiment.Thesetestswouldensurethatonlythecorrectamountofrequiredwaterwouldbedistributedtoeachzoneandwouldallowthesystemtobeeasilyretrofittedintoanyyard.Sinceourprototypeonlyneededtointerpretdatafromtwosensorstheamountofdataitcollectedwasrelativelylow.Infieldapplicationsthenumberofsensorsrelayingdatawillbemuchlarger,thereforethecontrolsystemwillhavetobefastenoughtoefficientlyprocesstheselargeamountsofdata.

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MARKETANDDEPLOYMENTRECOMMENDATIONS

Inordertomakeourproductappealingtoconsumersthereareafewareasthatneedtobeimproveduponbeforemakingitamarketableproduct:1)inquiretheskillsofanelectrical/softwareengineertodevelopauserinterfaceand2)createaproductwithsimplepartsforeasyintegration.

Thepotentialforthisprojectishugeintermsofuserinteractionwiththesystem.Ifweweretogetanelectrical/softwareengineerinvolvedwithdevelopingasimpleuserinterfacethenourproductappealgreatlyincreases.Theuserinputwouldsimplyneedtoprompttheuserforpertinentinformationregardingtheyardthatitisbeingimplementedinto.Also,futuredevelopmentswouldincludecreatinganappthatcouldbeinstalledontheuser’smobiledevice.ThenbyusingtheWi-FicapabilitiesoftheWandboard,theuserwouldbeabletointeractwiththecontrolsystemtherebybeingmoreinvolvedwiththesystemsoperations.Alongwithdevelopinganapp,simplifyingtheproductionofthecontrolsystemandthesensorswouldreduceconsumercostsandpotentiallyincreasingitsdemandandeaseofuse.

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CONCLUSION

Wesetoutwiththeintentiontodevelopsystemsthatreducetheenvironmentalimpactsofmodernhomeswithsimpleandaccessiblemechanicalengineeringsolutions.Thephilosophybehindthisgoalisthat,inadditiontotheappealofenvironmentallysustainabletechnologiestoconsumers,thesystemsthatcouldofferthegreatestpotentialforenvironmentalimpactreductionarethosethatarecost-effective,andthereforemechanicallysimple.Wesetouttodeterminethepotentialoftwosystemsaffectingtwocandidateproblems:1)anin-linefansystemworkinginparallelwithastandardHVACsystemtoreducetheenergyrequirementsandthereforeGHGemissionsofmodernhomesand2)arainwatercollectionandautomateddistributionsystemwhichcoulddecreasethedemandofmodernhomesfortreatedwater.Weconstructedphysicalprototypes,aswellascomputermodelsandsimulationsinordertodeterminethefeasibilityofthesesystems,andtheirpotentialimpact.OurresultsdemonstratethatsimplemechanicalsystemscantakeadvantageofindoorandoutdoorenvironmentalconditionstoofferdirectbenefitstoAlbertahomeowners,aswellastotheglobalmarket.

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TheHomeDepot.(2016).BrassHoseYW/shut-off.FromTheHomeDepot:https://www.homedepot.ca/en/home/p.brass-hose-y-wshut-off.1000121297.html

Wikipedia.(2016,March21).Watercontent.FromWikipedia:https://en.wikipedia.org/wiki/Water_content

APPENDICES

APPENDIXA–RAINWATERMANAGEMENTEXPENSEREPORT

Itemname Quantity Description PlaceofPurchase

Purchaser Price

24BITADC 5Analogtodigitalconverter-necessarytointegratesensorsintosystem

DigikeyElectronics

DanCojocariu $16.80

Solderlessbreadboard

1Breadboardisusedtointegrateallinputsandoutputstothemicrocontroller

DigikeyElectronics

DanCojocariu $6.88

Jumperwirebundle

1Wiresusedtoconnectinputs/outputsfromthebreadboardtothemicrocontroller

DigikeyElectronics

DanCojocariu $7.91

Shippingcost - - - - $8.00

Tax - - - - $1.58

TOTAL $41.17

WBDUAL-Wandboard

1Microcontrollerusedtoprogramcontrolsystem.Thisisthebrainsoftheoperationthatcontrolstheentiresystem

MouserElectronics

DanCojocariu $149.35

TOTAL $149.35

66

SoilmoistureEC-5sensors

3Soilmoisturesensorsusedtocollectdataforsystemtodeterminewhenplantsneedwatering

HoskinScientificLimited

DanCojocariu $390.00

Tax - - - - $20.66

UPSFreightCharge

- - - - $23.24

TOTAL $433.90

3.5mmStereoexternalcable

M/F4

Thesecablesareusedtoconnectandintegratethesensorsintothesystemduetotheconnectionrequirementsofthesensors

MemoryExpress DanCojocariu $27.96

FullyratedUSBcableA-a

1Thiscableisusedtoconnectthewandboard(microcontroller)tothecomputertoprogram


16GBmicroSDcard

1Usedforthemappingofthewandboard.Theinterface/programiswrittenontotheSDcardandpluggedintothewandboard


USBtotypeN5V 1Thiscableisusedtoconnectthewandboardtopowersothatitturnsonandoperates


Tax - - - - $2.65

TOTAL $55.58

SolenoidValve 3

Thesevalvesareusedtocontroltheflowofwatertotheindividualzones

AliExpress DanCojocariu $50.37

Customs/Duties - - - - $17.48

TOTAL $67.85

67

RelaySSR3A 1 Thisrelayisusedtooperatethepump,turningitonandoffDigikey

ElectronicsDanCojocariu $30.77

TOTAL $30.77

TransistorNPN,400V,3A

6Thetransistorsareusedinthecircuittoaidtheoperationofthevalves

DigikeyElectronics

DanCojocariu $5.58

Transistor,NPN,80V,15A

6Thetransistorsareusedinthecircuittoaidtheoperationofthevalves

DigikeyElectronics

DanCojocariu $7.74

Tax - - - - $0.67

Shippingcost - - - - $8.00

TOTAL $21.99

Variousirrigationsupplies

-Thisbundleofitemswasboughttobuildtheprototype.Therearemanylittleparts,listingeachwouldbetediousandunneccesary

HomeDepot DanCojocariu $116.41


-Thisbundleofitemswasboughttobuildtheprototype.Therearemanylittleparts,listingeachwouldbetediousandunneccesary


LawnSoil 1 Boughtadditionallawnsoilusedforthetestingoftheprototype HomeDepot DanCojocariu $6.28

BrasshoseYconnector

1Usedtooptimizethepressureonthepump,andintroduceawaterrecycleintothesystem(prototypeoptimization)



-Additionalirrigationsuppliestooptimizetheprototype.Aftertestingwasdoneandissuesidentified,thiswasdeemednecessary


68


-Additionalirrigationsuppliestooptimizetheprototype.Aftertestingwasdoneandissuesidentified,thiswasdeemednecessary


GasketSealer 1 Usedtosealthepumpandensurenoleakage CanadianTire DanCojocariu $7.34

TOTAL $224.48

RUNNINGTOTAL

$1,025.09

Robinson, J et al. - Sustainable Control Systems in the Modern Home - ENME 538

Documents

Transcript of Robinson, J et al. - Sustainable Control Systems in the Modern Home - ENME 538