Post on 22-Mar-2016
description
EvaluatingLowCarbonStrategies.
CaseStudy:Chalbury.Poole.
AndreaLuiseSchrader.
06098672@brookes.ac.uk
OxfordBrookesUniversity.
Abstract.
Inthispapertheauthorexplorestheenergyuseandlowcarbontechnologiesofthecasestudy:Chalbury, Poole, with focus on a single residential unit. The annual energy use is calculatedfromactualenergydataandaratingofCSH5isdefinedfor itsannualpoweruse.Analysisofthequalityofarchitectural fittingsandappliances, lightandthermaldelightwithintheunit isundertaken,withfurtherreflectiononcommunalspaceswithinthebuilding.Finallycomparisonismadetoanotherunit,toinvestigateanychangesinspatialqualitythatarisefromadifferingorientationwithin thebuilding.Conclusion isdrawnon theoverall successof the lowcarbonfeaturesofthecasestudy.
Chalbury. Planning Documentation. Whitelock Architects. Bournemouth. UK.
SummaryofDevelopment.
Location:
Chalbury.34TheAvenue.Dorset.Poole.
Chalbury issituatedonthesoutherncoastofEngland inBranksomePark,Poole.Thisarea isadenseresidentialdistrictwithmaturevegetationandgreenlandscapingthroughout.Therearemanyprotectedtreeswithinthearea
(andtheChalburysiteitself)whichcanbeupto80/100ft.
TheChalburysitestemsoffTheAvenue,abusyarterialroadthatrunsfromBournemouth,throughBranksomeParktowardsSandBanksandtheBranksomeBaybeach.
Aerial Photographs taken from Google Maps (2008).
CaseStudyUnit.5Chalbury.
NetInternalArea(i.e.excludingterrace):1369sqft/127.184sqm
TheflatissituatedonthefirstfloorandpredominantlyconnectswiththeNorthfaçadeofthebuilding.
Plans courtesy of The Whitelock Group (2008) www.whitelock.co.uk.Bournemouth,UK.
BuildingInformation.
Architect:TheWhitelockGroup.
DateOfCompletion:June2007.BuildingUse:Residential.
LG:CarParkingFacility.GF:ReceptionArea/Residential.
Floors01–05:Residential.BuildingMass:5storeysandBasement.TotalNetInternalArea:21270sqft.CarGarageSpace. 3954sqft.CirculatorySpace.(incl.riser/plant/cleaningstore) 3440sqft.UnitSpace. 13876sqft.Thisiscomprisedof16unitswithnetinternalfloorareas:
Type1:8X1050sqft.Type2:4X1369sqft.Type3:2X1420sqft.
EnergyDataAnalysis.
Assesmentofenergyperformanceinreferencetobenchmark.
So to improveaccuracy Iwillnowcompare tomoreconventionallyusedbenchmarks.TheCodeForSustainableHomes benchmarks on total energy consumption per squaremeter states that a usage of 73.943 kWh/sqm is
categorizedasCode5CSH.
FuelConsumptionFiguresfor5Chalbury(CaseStudyUnit):
SeparateEnergyCostsAndData=
AnnualElectricityBill=£534perannum(SouthernElectricrates,HistoricalFigures:2007/8)
5.75pperkWh:9286.957kWhperannum
0.550Kg/CO2/kWh:5107.826Kg/CO2/kWhperannum
AnnualGasBill=£452perannum(BritishGasDomestic,HistoricalFigures:2007/8)
10.52pperkWh:4296.578kWhperannum
0.190Kg/CO2/kWh:816.350Kg/CO2/kWhperannum
TotalEnergyConsumption=
9404.404kWhperannum
73.943kWh/sqmperannum
TotalCarbonFootprint=
5924.176Kg/CO2/kWhperannum/5.912metrictonnes/CO2/kWhperannum
=4.327Kg/CO2/sq.ftperannum
ClimaticContextAndNicolGraph.
TheNicolgraphshowsthatbetweenthemonthsofApriltoAugusttherearehighsolargainsthathavepotentialto
beutilizedinmaintainingTc,andapassivelyheatedenvironment.
Nicol Graph showing climatic data from the Evesham area, closest weather station to the site. Historical data collated from the online database, Met Office. UK. (2006)
According to theNicolGraph, thecomfort temperature foran internal spacewithin theBournemouth/Poole/
Eveshamarea fluctuatesbetween14and21degrees (peakingonlyat this temperature in JulyandAugust).Theproprietor of 5 Chalbury heats the flat to the peak of this at an estimated 21 degrees between themonths of
SeptemberandMay.
TheNicolGraphalsoshowsthereisconsiderablechanceforutilizingsolarheatgainswithinthemonthsofMay–
August. The proprietor stated that he defines the period at which he heats the unit by his perceived thermalcomfort. In it’syearofoccupation,theproprietorswitchedoffheating inMaydue internalconditionsbecoming
toohot.Itshouldbenotedthatthiscoincideswiththemonthsshownwithconsiderablyincreasedsolarirradiance.
Theproprietor claimed tobehappyat this constant21degree temperaturewithin theheatedmonths, butdidtakeinterestintheNicolGraphshown,andhasconsideredtestinglowertemperaturesofspaceheatingfromit’s
indicationofalowerTc.
CriticalEvaluationOfPassiveDesignFeatures.
Heating/Cooling.
Heatingwithintheflatunits isunderfloor.Hotwater isprovidedbyaVokeraMynutehighefficiencycondensingboiler category II2H3P.Hotwater is circulatedunderfloor in piped circuits to each room,which have individual
thermostaticcontrols.Therearesevenzoneswithinthecasestudyflat,andcanbepresumedmuchthesameintheotherunits.
Allowing each zone to be controlled separately reduces unnecessary heating and consequent energy use. The
authornotedthattheproprietorof5Chalburyheatedroomsoffrequentuseatahighertemperaturethanroomslessoccupied.
Thesystemisonatimerallowingthehousetobeheatedattimessuitingitsoccupancy.Theproprietorheatedthe
flatfrom4.30–8.00and16.30–20.00whichkeptitatacomfortabletemperaturethroughouttheday,withit’swarmestperiods(midmorningandearlyevening)attimesofgreatestoccupancy.
Underfloor heating allows greater user comfort at lower intensities of space heating. Unlike common radiator
systems, underfloor heating, starts heating at the lowest point, utilizing the convection of heat upwards topermeate thespacevolumequicker.Thisallowsheat to reachutilized (lower,andmorecentral) spacesquicker
andtheuserfeelswarmeratlowerheatsettings.
The communal spaces within the building core are unheated, relying on the thermal mass of the building to
maintainacomfortabletemperature.Thecirculationspaceiscentralintheplanandissurroundedbytheheatedunitsfurtherreducingheatlossestotheexternalandutilizesresidualheatgainsfromtheunits.Theauthornoted
thatthesespaceswereatanacceptablecomforttemperature(allyearincludingwintermonths)suitingthebrieftimetheyarewalkedthroughtoenter/exitflatunits.
ThermalMass/Insulation/Acoustics.
Theexternalwallsarecomposedofthefollowing:
StandardStone>100mlCavity>50mlKingspanThermal>100mlDenseConcrete>DryLining
Faces Insulation Block
AtfloorlevelthecavityisclosedoffbyRockwallfireseparatorandalsoatthepartywall.
AllwindowsandexternaldoorsarePVCdoubleglazed.Thisprovidespremiumthermalandsoundinsulation.The
authornotedthattherewassomeexternaltrafficnoiseheardinthemasterbedroom.Thermally,bothauthorandoccupantagreedthebuildingperformedwell.
Theoccupantinstalledshuttersinthelivingarea,inreplacementofcurtains.Theseareclosedintheevenings,and
theAuthornotedthatthisdoeshelpreduceheatlossesthroughtheglazing.
AppliancesAndPlugLoads.
Energydemandfromplugloadsisreducedbyfittingenergyefficientappliancesinthekitchenandbathroomsoftheunits.Thekitchenswerefittedtothearchitect/developersrequiredspecification.Allappliances;dishwasher,
washingmachineandfridgefreezer,areAorAAratedenergyefficient.ThehobisaBoschelectricinduction(thatuses soundwaves to provide instant heat and cooling) and the 2 ovens are Bosch thermo fan energy efficient
appliances. Showerheads, althoughoffering a “power shower” setting, canbe set to a reduced flow. Bathroomtapshaveanaeratedstream,furtherreducingwaterconsumption.
ArtificialLighting.
Lighting in the apartment is provided by low energy compact fluorescent, low voltage halogen and LED (latest
technologylightemittingdiode)lightbulbs.Lumens/wattforLEDlightsourcesareincrediblyefficientandcanlastmanyyearswithoutreplacement.
Commonareashavelowenergycompactfluorescent,lowvoltagehalogenandLEDinternallightingsystems.LEDlight sourcesprovidecontinuous low level lighting in corridors,whereasallother lighting is switchedbymotion
detectionsensorsthroughoutthebuilding.Outdooranddrivewaylightingislitbyhighpressuresodiumbollardsonalightsensorswitch.
Both author and proprietor agreed that lighting was pleasant and sufficient. Whilst lighting in the communal
spacesisdimmer,duetotheLED’sused,theygavesufficientlightforthepurposeofabrieflyoccupiedhallspace.
Theauthoralsonotedthattheproprietormaintainedastrictlightusepolicywithintheunit,onlyhavinglightsonintheroomsoccupiedatthetime.Thiswouldhaveaconsiderableaffectonenergyuse.
NaturalLighting.
Thesungetsconsiderablenaturallightthroughouttheday.Therearelargeglazedpanels(2100x1800withJuliettebalconies)fromthebedroom(Easternelevation),secondbedroomandofftheloungespace(Westernelevation).
Theauthornotedthesunpaththroughouttheday.Areasofconsiderablenaturalday‐lightingareasfollows:
Morning:
Midday:
Afternoon:
Entireterracewithsomeshadingfromnearbytrees.Livingspace.
Living/Diningspace.
Easternsideofterrace.Masterbedroom.
Theshuttersintheliving/diningareaareusedforsolarshadingwithintheday(ifnecessary),reducingglareand
improvingthermalcomfort.
Annotationforfigures:Fromtoplefttobottomright.
Fig.1:Afternoonsunlightinthemasterbedroom.
Fig.2:Thermostaticcontrolforunderfloorheating.Zonespecific.
Fig.3:LargeglazedwindowwithJuliettebalcony,inthesecondbedroom.
Fig.4:Kitchenspace,withlowenergylightfittings.(turnedonforpurposeofphotograph).
Fig.5:EnergyEfficientkitchenappliances:Hobtospec.asstatedintext..
Annotationforfigures:Fromtoplefttobottomright.
Fig.6:Boilerservicingtheunit.
Fig.7:OvenswithAAenergyrating.
Fig.8:LEDlowlevelcontinuouslightingincommunalspaces.
Fig.9:Passagetowindow/AOVallowingnaturallightintothecommunalcirculationcore.
Fig,10:LEDlowlevelcontinuouslightinginreception.
Fig.11:Morningsunenteringlivingspace.Notealsotheshuttersinstalledforsolarshading,privacyandinsulation.
Ventillation.
The windows in the living / dining space, master and second bedroom are 2100x1800 with Juliette balconiesprovidingoptimumventilation(largestpossibleconventionalwindowsize)andallowinguserstosustainagoodair
quality/CO2levelwithintheunit,abstainingissuesrelatedtoSickBuildingSyndrome.
There is however, minimal ventilation within the stair core / circulation spaces. The only connection wit theexternalenvironmentisthroughtheAOV(whichcanbeopenedmanuallybuttendtoremainclosed,onlyusedin
eventofafire)andGFreceptiondoors.Thisreductioninventilationisnecessarytomaintainthepassivethermalheating of this space from surrounding units and thermal mass. However, ventilation could be improved by
including a double glazed roof light for ventilation on the 5th floor roof level. This would allow “Stack Effect”naturalventilationwhilstutilizingasmallamountofsolargainonthisupperfloor.
ComparisonOfCaseStudyAndUnitOfOpposingOrientation.
Afterbriefinspectionofunit7,(secondfloorwithsouthwesterlyorientation)theauthornotedthatbothflatsgot
considerablesolargain.TheproprietorsofUnit7hadinstalledblindstocombatexcessivegainsinsummermonths.Theauthorfoundtheflat,atthetimeofthevisitinNovember,thermallycomfortable,contributedto
greatlybysolargains.
Fig.12:(left)Blindsaddedtoreducesolarglare
/improvethermalcomfort.
Fig.13:(below)Living/diningspaceofUnit7.Bothflatshadconsiderablenaturallight
throughoutthedayinthisarea.
Conclusions.
Theunitstudiedhasproventoperformwellagainstcontemporarybenchmarksoflowenergyuse.Ananalysisofitslowcarbontechnologiesshowsthatit’slowenergyuseiscontributedtogreatlyfromthearchitecturalfeaturesandfittings.
However,itshouldalsobetakenintoaccountthatthelowenergyconsumptionwillhavebeencontributedtobythereducedoccupancyoftheunit(2personaswithina3bedroomflat).Theproprietor’s use of communal spaces and consequential resultant energy use has not beenconsideredandmayhaveaneffectonthekWh/sqmfigurerecorded.
Fromobservationoftheflatusageoveraprolongedperiodoftime,theauthoralsoconcludesthat reductions in energy costs is contributed to considerably by the efficient energymanagementsustainedbyit’soccupants.