* M.Sc. Eng. KatarzynaNowak-Dzieszko,M.Sc. Eng.Małgorzata Rojewska-Warchał, Institute ofMaterialsandBuildingStructures,FacultyofCivilEngineering,CracowUniversityofTechnology.

TECHNICAL TRANSACTIONSCIVIL ENGINEERING

5-B/2014

CZASOPISMO TECHNICZNEBUDOWNICTWO

KATARZYNANOWAK-DZIESZKO,MAŁGORZATAROJEWSKA-WARCHAŁ*

MEASUREMENTSOFTHETHERMALCOMFORT INTHEW70PANELBUILDING

POMIARYKOMFORTUCIEPLNEGOWBUDYNKUWIELKOPŁYTOWYMWSYSTEMIEW70

A b s t r a c t

Itisestimatedthatabout4millionflatsinPolandaremadeofprefabricatedelementsindifferentsystems.Moreover,atpresentmorethan10millionPolesliveinsystembuildings.Despitethecommonnessofthosebuildingstheanalysesofthemicroclimateoftheinteriorspaceareveryrare.Thepaperpresentstheresultsofthethermalcomfortmeasurementsconductedindifferentflatsofmulti-familypanelbuildingmadeinW70system.Itappearsthereisaproblemwiththeoverheatingeffectduringthesummermonthsinallpartsofthebuilding.

Keywords: panel building, W70 system, thermal comfort measurements, PMV (Predicted Mean Vote), PPD (Predicted Percentage of Dissatisfied)

S t r e s z c z e n i e

Szacujesię,żewPolsceokoło4milionówmieszkańwykonanychjestwtechnologiwielkiejpłytywróżnychsystemach.Cowięcej,obecnieponad10milionówPolakówmieszkawbudyn-kachsystemowych.Pomimopowszechności tychżebudynkówanalizymikroklimatuwnętrzjest bardzo rzadkie.W artykule przedstawionowyniki pomiarów komfortu cieplnego prze-prowadzonychwróżnychmieszkaniachwielorodzinnegobudynkuwzniesionegowsystemieW70.Okazujesię,żewewszystkichanalizowanychmieszkaniachwystępujeproblemprze-grzaniawmiesiącachletnich.

Słowa kluczowe: budynek wielkopłytowy, system W70, pomiary komfortu cieplnego, PMV (Predicted Mean Vote), PPD (Predicted Percentage of Dissatisfied)

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1. Prefabricated panel buildings

In thefiftiesof the twentieth century the erectionofpanel systembuildingsbegan inPoland.Fortheseveraldozenyearsabout4millionsflatshavebeenadjustedtouse.Atpresentmorethan10millionPolesliveinsystembuildings.Itmakestheproblemsconnectedwiththeproperusageandthermalinsulationveryimportantandcommon.Thethermalinsulationofthosebuildingsislowandtheseasonalheatingenergydemandisusually50%higherthanthenationalrequirements[1].Themostimportantaspectistheimprovementofthebuildingenergycertificateofthosebuildings.Itisconnectedwiththethermalmodernizationofthebuildingenvelopeandchangeofwindows.

Unfortunatelyatthestageofconsideringanddesigningthethermalmodernizationno-onetakesintoaccountthethermalcomfortandoverheatingissuesinsummerwhichseemtobeveryimportantfromtheoccupants’pointofview.

TheW70Systemisthe”opened”systemusedfortheerectionofmulti-familybuildings,in which, contrary to the “closed” system, all construction walls within the flats wereeliminated.Itallowedthechangesofthepartitionwallpatternandatthesametimeenableddesigningofflatswithdifferentareasandroomarrangements.Itisestimatedthatabout15%ofallsystembuildingswereerectedthisway.

2. Thermal comfort

Thermal comfort is related to the thermal balance of the body which is affected bydifferentparameters:personalandenvironmental.Themicroclimateoftheinteriorspaceisthecombinedeffectofthedesignprocess,erectionandtheutilizationofparticularrooms.Thermalcomfort isaffectedbyhumanactivity,clothing insulationand theenvironmentalparameterssuchasairtemperature,averageradiationtemperature,airflowspeedandrelativehumidity.TheevaluationofthermalcomfortisbasedonthePMV(PredictedMeanVote)andPPD(PredictedPercentageofDissatisfied)indices.

TheinternationalstandardPN-ENISO7730”Ergonomicsofthethermalenvironment.AnalyticaldeterminationandinterpretationofthermalcomfortusingcalculationofthePMVandPPDindicesandlocalthermalcomfortcriteria”[4]usesFanger’smethodtoestimatethermalcomfort.

The Fanger’s PMV method combines the following environmental features: airtemperature,airvelocity,meanradianttemperatureandrelativehumidityandtwopersonalvariables:clothinginsulationandactivitylevelintotheindexthatcanbeusedtopredicttheaverage thermalsensationofa largegroupofpeople.The thermalsensation7-levelscalewithvaluesbetween–3and3describesthethermalsensationbetween“hot”and“cold”.

In thismodel, allmajormodes of energy losses from the humanbody are taken intoaccountandthepersonisassumedtobeatthesteadystatecondition.

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3. Flats analyzed

TheaimofthefieldmeasurementswastoanalyzethethermalcomfortintheparticularpartsoftheW70paneldwellingbuilding,builtin1974(Fig.1).Thetestswereconductedusingthedigitalthermalcomfortmeasurementdevice(Babuc),Fig.2Infogapprogramtoanalyzetestdata.

a)b)

Fig.1a)Southelevationoftheanalyzedbuilding, b)locationofflatsatbuildingfloor

Fig.2.BABUC–deviceusedtomeasurethermalcomfort

Buildingplanarea21.5×13.2m;usagebuildingarea–2279m2,25mhighwith11levels.Basementbelowtheentirebuilding,flatroof.

Buildingwiththenaturalventilation,centralheatingsystemwithconvectionheaters.Communicationarealocatedinthecenterpartofeachbuildinglevel.Fourflatsatevery

storylocatedinthecornersofthebuilding.Thefieldtestswereconductedinthreeflatsatdifferentlevelsandwithdifferentwindow

orientation:1)Flatnumber1–groundfloor,South-Eastorientation,2)Flatnumber2–fifthfloor,South-Westorientation,3)Flatnumber3–seventhfloor,North-Eastorientation.

Exteriorwallsmade of prefabricated panels inW70 system, insulatedwith 10 cmofstyrofoamwithplastersatbothsides:U=0.25[W/m2K],doubleglazingwindows:U = 1.7 [W/m2K].

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4. Test results

Themainaimofthefieldtestswastoanalyzethemicroclimateconditionsoftheparticularflatsatdifferentelevationsduringsummer.Measurementsallowedtodeterminetheinternaloperativetemperatures,andtherefore–basedonthemeasurementdata–calculatethevaluesofPMVindexandPPDindex.

Themeasurementswere conducted in three days between 29th July and 31st July, for24hoursineveryflatreferencedabove,startingatseventhfloor,nextofthefifthfloorandfinallyatgroundfloor. Ineachcase themeasuringdevicewas located in the living roomwherethepercentageofglazingatexteriorwallsisthehighest.

Theaverageexternal temperaturesduring thosedayswereevenabove30°Candweremeasuredcontinuously, the resultsarepresented inFig.3.Theelectronicdeviceusedfortemperaturemeasurementswaslocatedatthebalconyofeachflat.

Fig.3.Externaltemperaturebetween29thand31stJulyinCracow

Inalldwellingstheoperativetemperatureintheanalyzedperiodoftimeisconsiderablyhigher than 25°C. The dailymaximum interior operative temperature is 29.17°C. Thosenegativeflatconditionscontinuefortheentiredayanddonotchangesignificantlyatnight.Theflatscanbecooleddownduringthenightthroughtheopenwindows.However,incaseofsuchhighexternaltemperatures, itdoesn’tchangetheoperativetemperaturemuch.AlldataarepresentedinFig.4.

Fig.4.Internaloperativetemperaturesbetween29thand31stJulyintheanalyzedflats

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Thethermalcomfortconditionsarecloselyrelatedwiththehumanactivityandclothinginsulation.Theparameterclo=0.5describingclothing insulation,basedon standard [3],wasassumedinthecalculationsofPMVindex.Regardinghumanactivity,twocaseswerecalculated:firstoneforapersonhavinga restand thesecondoneforapersondoing thecleaning.

Figure5presentsthePMVvalueswiththeassumptionthatflatusershavearest.FormostofthetimethePMVvalueisbetween–0.5and0.5,fortherestofthetimeit’shigherthan0.5butnotmorethan1.

Fig.5.PMVindex–usershavingarest

Theresultsaremuchdifferentwhenweassumedifferentactivitylevelofpeoplestayinginside theflats. Figure 6 presents the results.ThePMVvalues aremuchhigher than1.5almostfortheentireperiodoftime.Thosearenotcomfortableconditionsforusers.

Thepredictedpercentageofdissatisfied,describedbyPPDindexintheanalyzedperiodoftimeisbetween50%and80%(Fig.7).

Fig.6.PMVindex–userscleaningtheroom

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Fig.7.PPDindex–userscleaningtheroom

5. Conclusions

Theresultsofconductedanalysisshowthattheoverheatingprobleminsummeroccursinallflatsofthepanelbuilding.Windowsintheprefabricatedpanelbuildingsinmostcasesarepoorly shaded from solar radiation.Glazing is the sourceof the excessiveheat gainsandresultsinoverheatingofthedwellings.Themicroclimateconditionsinallflatsareveryuncomfortableandtheparametersdescribingthermalcomfortexceedtheacceptablevalues.Theoperativetemperaturesaremuchhigherthan25°CandthePMVvaluesformostofthetimearebetween1.5and2andthepercentageofdissatisfiedpeopleforallthetimeishigherthan50%.

In case of all flats the internal or external shadings should be used to improve themicroclimateconditionsandreducetheinternaloperativetemperatures.

R e f e r e n c e s

[1] RozporządzenieMinistraInfrastrukturywsprawiewarunkówtechnicznych,jakimpo-winnyodpowiadaćbudynkiiichusytuowaniezdnia12kwietnia2002.

[2] Ostańska A., Wpływ dotychczasowych termomodernizacji budynków mieszkalnych na oszczędność energii i planowanie programów rewitalizacji na przykładzie jednego z lubelskich osiedliBudownictwoiArchitektura7,2010,89-103.

[3] PN-ENISO7730Ergonomicsofthethermalenvironment.Analyticaldeterminationandinterpretationof thermal comfort using calculationof thePMVandPPD indices andlocalthermalcomfortcriteria.

[4] NowakK.,Modernizacja budynków a komfort cieplny pomieszczeń,EnergiaiBudynek,11(54),2011.

[5] DębowskiJ.,Cała prawda o budynkach wielkopłytowych,Przeglądbudowlany9/2012.