1Karime Marouf, Applied Thermodynamics and Solid Fuels, Mohammedia School of Engineering, University Mohammed V, Rabat Morocco.
3 NEW INSTALLATION
Karime MAROUF1, Said HACHIMI2
Abstract Faced with the challenges of the rapid increase in energy consumption in Morocco, where more than 95% of runninginstallatarticleswimmingmixedwithTosystems.variousthroughitselfconsumption.systemslatter,becomeenergyneedsareimportedfromoutside,energyefficiencyhasoneofthekeyissuesinallareasofactivity.InthetheenergyneedsareveryvariedandtheheatingrepresentasignificantpartoftheelectricityAccordingtotheAMEE[1],Moroccohassetthegoalofachievingenergysavingsof15%by2030,theimplementationofanenergyefficiencyplanintheeconomicsectors.Thisisparticularlytheheatingrespondtothissituation,wereplacedagasboilersystemgroundsourceVRF(variablerefrigerantflow)heatpumpwithaerothermalVRFforheatinganoutdoorpoolinRabat(Morocco).TheobjectiveofthisistoanalyzetheelectricalconsumptionofthenewionanddefinetherealROIbasedontwoyearsofthispilotsite
Over the past decade, the country's energy needs have increased significantly. This is mainly due to the industrialization of the country and the good global economicdynamics.
Mostoftheheatusedfornon electricheatingresultsfrom the combustion of hydrocarbons. The combustion of gas mainlyemitswatervaporandcarbondioxide(CO2).Thus, Morocconotesaweaknessofnon renewableresources.
The well is at 22 m, with a temperature of 15°C and a capacityof20m3/h
2Said Hachimi, Applied Thermodynamics and Solid Fuels, Mohammedia School of Engineering, University Mohammed V, Rabat Morocco. ***
Morocco is an energy importing country because it has virtuallynonaturalresourcestomeetitsenergyneeds.
A heat pump (VRF) is a thermal machine that uses mechanical energy (compressor pumps) to extract low temperatureheatfromanenvironmentandrestoreitata highertemperaturetomakeitusableforheatingneeds.
Wehaveinstalleda mixsystem between30%geothermal heatpumpand70%aerothermal heatpumptoguarantee energyperformance. Thesettemperatureis29°C
In view of these elements, the exploitation of geothermal resources in Morocco allows the production of thermal energy in a sustainable way for the heating of swimming pools.
Toestimatethecalorificpowertobeinstalled,aheatbalance mustbecarriedouttakingintoaccountthemostunfavorable externalconditionsoftheyear:
REPLACEMENT OF GAS BOILEIR BY GEOTHERMAL/AEROTHERMAL VRF-HEATPUMP FOR SWIMMING POOL HEATING IN MOROCCO.
Thepricepaidforoneyearis:1050000MAD(Moroccan dirham)
1. INTRODUCTION
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p ISSN: 2395 0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page255
Thermalbalanceduringthefillingphaseinordertodeduce thecalorificpowerrequiredduringfillingP1.
Thermal balance enabling the calorific power required to maintainthetemperatureofthepoolwaterat28°Cduring theoperatingperiodP2tobededuced. With: Estimation of the heating capacity during the filling phase: P1=Surfacelosses+Wallheatlosses+Waterandconcrete heating Solargains Surface losses = Losses by evaporation + losses by convection+lossesbyradiation
Key Words: Swimming pool heating, very low enthalpy geothermal energy, VRF, Geothermal, Aerothermal, Electricityconsumption,ROI.
2 EXISTING INSTALLATION
Thesystemisequippedwithtwopropanegasboilerswith anoutputof800kW. Annualpropaneconsumptionisapproximately81.4tonnes
TheaveragepriceofpropaneinMoroccoduringtheyearof operationis12.9MAD/kg
Outsidetemperaturewhenfilling:10°C Desiredwatertemperature(setpoint):28°C
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p ISSN: 2395 0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page256
Evaporation loss source ASHRAE 2019: Whenthevaporpressureoftheambientairislowerthanthe saturated vapor pressure at the surface of the water, evaporationofwateroccurs. In the literature, several scientific formulas deduced from experiments make it possible to quantify losses by Inevaporation.thisproject,IchosetousetheformulafromtheAmerican ASHRAE2019[2]: kW 0,0890,07820,5evapwaterwa PSPPV kPa % aw PHRP 0.5:With:isacoefficientlinkedtotheactivityinthebasin.During thefillingphase,thereisnoswimmer.Wethenmultiplybya coefficientof0.5,asshowninthefollowingtable. Thefollowingactivityfactorsshouldbeappliedtotheareas ofspecificfeatures,andnottotheentirewettedarea:
kW 310convwaterCwateramb PShTT
Ambientairspeedat1mfromthepoolsurface:V=1.2m/s Pw(saturatedvaporpressure):atT=28°C,Pw=3.783kPa Pa (saturation pressure): at T = 10 °C and for relative humidityRH=70%; kPa 0,71,2280,86a P Swater=340.12m2(Watersurface) kW 90,89evap P
Convection loss: Convectionisoneofthethermalheattransfermodes.Asthe airabovethepoolmovesatanyspeed,thewatermolecules alsomove,causingthermal heattransferintheevent that thereisatemperaturegradient. Also,severalscientificexperimentshavebeenmadeinthis direction,inordertopresentaformulaforquantifyingthe heatexchangecoefficient.Theformulausedinthisstudywas alsotakenfromtheASHRAE. W/m2.K 5,73,8c hV
ForawindspeedofV=1.2m/s kW 62,81conv P Radiation loss: Everything emits radiation of an electromagnetic nature, whatever its state: solid, liquid or gas. This emission of energycomesattheexpenseofthebody'sinternalenergy. Water exchanges with the environment by radiative heat Thistransfer.radiative exchange is expressed by the following kWrelation: 8443 5,6810(273)(273)10raywaterwaterwaterskyamb PSTT 0,0040,8skydew T DigitalApplication: ForTamb=10°CandRH=70%,Tdew=4.79°Ctherefore 0,82sky kW 49,04ray P Surfacelosses=202.74kW Losses through the walls of the basin: Heatlosses represent heatlossesthroughthe wallsofthe basin.Theyareallthemoreimportantwhenthewallsare poorlythermallyinsulated. Thethermallossesareexpressedasfollows: kW 310waterearthQUST
P1 = Estimation411.93kWof the heating capacity during the maintenance phase: P2 = Surface losses + Wall heat losses + Renewed water heater Solargains Surface losses = Losses by evaporation + losses by convection+lossesbyradiation
Evaporation loss source ASHRAE 2019: Asaresultoftheactivityofbathers,evaporationlossestend toincrease.Itisthereforenecessarytotakeintoaccountthe impactoftheactivityofbathersduringthisphase. AccordingtotheASHRAE2019,forpublicswimmingpools, the equation must be multiplied by the activity factor Fa (FactorActivity):1 kW 0,0890,07821PSPPV
Weusetheunfavorableclimaticconditions: Outdoortemperature:4°C Desiredwatertemperature(setpoint):28°C Ambientairspeedat1mfromthepoolsurface:V=1.2m/s Pw(saturatedvaporpressureathotwatertemperature):at T=28°C,Pw=3.783KPa Pa(saturationpressureatambientairtemperature):atT=4 °CandforrelativehumidityRH=88% kW 190,73evap P Losses by convection: Theunfavorableexternalconditionsbeingthesame;during thetemperaturemaintenancephase,convectionlossesare calculatedasfollows: kW 83,75conv P
evapwaterwa
Water and walls heating: Toreachthesettemperatureinthebasin,itisnecessaryto raise the temperature of the water and the walls of the concretebasin,fromtheirinitialtemperaturestothedesired temperature. Water heating: According to the calorimetry relationship, the capacity required to heat the volume of water in 72 hours is as kWfollows: 3600 w wwPfinalwaterinitialwt wat aer er P VCTT h kW 197,38waterP Heating of the walls: According to the calorimetry relationship, the capacity required to heat the walls of the basin made especially of concreteforaperiodof48hoursisasfollows: kW 3600 c ccPfinalconcreteinitialconcrete wallP VCTT h Digital ConcreteApplication:volume:Sconcretexconcretethickness=57.2m3, withconcretethickness=0.4m ConcreteCp:0.837KJ/Kg.K Concretedensity=2500kg/m3 InitialconcreteT(average):9.5°C Tfinalconcrete(average)=((Hotwatertemperature+earth temperature)/2) kW 250057,20,83721,510 723600wallP kW 5,31wallP PHeating =Pwater+Pwalls PHeating =202.69Kw Solar gains (inwinter)=0W
DigitalApplication: Thesurfaceoftheconcretewalls:143m2 Tearth:15°C,temperatureoftheearthinwinter. Twater:28°C U:thetransmissioncoefficientofconcreteisaround2.5W/ m2.K,butforsafetymargin,wetakeacoefficientof3.5W/ kWm2.K 6,5Q
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p ISSN: 2395 0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | 257
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International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p ISSN: 2395 0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page258
Water heating renewed: Topreservethequalityandvolumeofwateroverthelong term,watermustbeconstantlyrecycled.Accordingtoarticle D1332 6ofthepublichealthcodeinFrance,anintakeof30 litersperdayandperbathermustberespected.Thisruleis alsorequiredinMorocco. Waterrenewalrateperday:30litersperbather. Estimatednumberofpeopleperday:90people. Volumeofwatertoberenewed:RenewalratexNumberof Calculationpeople.ofthevolumeofwatertoberenewedperday: l Volume of water renewed = Renewal rate x Number of lpeopleVolumeofwaterrenewed=30litersx90 lVolumeofwaterrenewed=2700liters m3Volumeofwaterrenewed=2.7m3
The capacity needed to heat the pool in 72 hours is P1 = 411.93kW,whilethetemperaturemaintenancecapacityis P2 = 341.99 kW. The largest capacity is used to select the equipmenttobeinstalled.Therefore,weinstalledacapacity ofP=441 InstallationkWdiagram:
Theentirefacilitycontained: 2geothermalunittomaketheexchangewiththeexchanger throughsoftenedwater,andwiththehydrokitsthroughthe refrigerant.Thecapacityofeachoutdoorunitis63kW. 5 aeraulic units to make the heat exchange with air and with the hydro kits through the refrigerant. The calorific powerforeachgroupis63kW.
An exchanger to exchange heat between the geothermal groupsandthewells.
14 hydro kits for the exchange between hot water and refrigerant.Asubmersible pump designed to fetch hot water from a depthwhereitisimpossibletosuckitfromthesurface.
The safety valves for pressure release in case of overheatingoftheinstallation. Themanometerstomeasurethepressure.
Radiation losses: Theunfavorableexternalconditionsbeingthesame;during the temperature maintenance phase, radiation losses are calculatedasfollows: kW 58,66ray P Surfacelosses=333.14kW Losses through the walls of the basin: kW 6,5Q
Thethermometerstomeasurethetemperature. The automatic air vents that allow the installation to operateinthebestconditions.Iteliminatesair,thepresence of which disrupts heat exchange, which causes noise and promotescircuitcorrosion Expansion tanks to absorb variations in the volume of waterduetotemperaturechangesintheinstallation.
Acirculationpumpstofloathotwaterinthepipes. Theflowswitchesmakeitpossibletocheckthepresenceof aminimumflowintheinstallation
Anti vibration sleeves for absorbing the vibration of circuitsandpumps.
Thecapacityrequiredforheatingtherenewedwater: kW 3600 w wwrPfinalwateril r nitiawate end r ewe P VCTT h kW 2,35renewedP Solar gains (inwinter)=0W P2 = 341.99 kW
Hydrokit WaterPipinginstallation:
In each zone, we recommend to add a pump. During maintenance,thepumpcanallowtheoperation. Werecommendtousewaterpipingexpertizeinorderto maintaininstallationquality.
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p ISSN: 2395 0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | 259
Non returnvalvestocontrolthedirectionofcirculation. Balancingvalvestocontroltheflowandpressure.
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Forthedrainpipesize,weusedthesamediameterasthe productconnectedorlarger. Weinstalledanaturaldrainagesothatthedrainedwater doesnotbackflows. To replace the connected device easily, we installed the unionjoint. Weinstalledtheserviceporttocleantheheatexchangerat eachinletandoutletofthewaterpipe. Weinstalledthestraineronthehorizontalpipe.(Whendirt, trash, rusted pieces get into the water pipe system, it can cause problems to the product by corroding the metallic material.)Weinstalledtheairventatthetopofthewaterpipe.Ifthe airventis not installed atthetopof thewater pipe, there wouldbealotofbubbleinthewaterpipe.Soa plateheat exchanger burst may happen because of the reduction of waterflowrate(CH14isdisplayedintheremotecontroller) causedbyalotofbubbleinthewaterpipe.
Weinstalledathermometerandpressuregaugeattheinlet andoutletofthewaterpipe. Weinstalledthedrainvalvethatcanbeusedfordraining the water inside when replacing the part or providing service.Weinstalledtheshut offvalvetoblockthewaterbyclosing thevalvewhenreplacingthepartorcleaning.
Weinstalledexcessivepressuresafetyvalvethatmeetsthe designwaterpressuretopreventunitorwaterpipedamage atthepressureincreaseinsidethewaterpipesystem.
Drainvalves. Shut offvalvestoisolatethecircuit. Thecollectorstoaccumulateanddistributewater.
Afterstudyingthesystemfortwoyears,thediagrambelow clearly defines additional guidelines to optimize the performanceoftheentiresystem.
Expansiontankneedstobedesignedbasedontotalpiping lengthandwatervolume. Itisnotnecessarytoinstallexcessivepressuresafetyvalve ineachpipe.Werecommendtoinstallinmainline.
2 Heat exchangers are recommended nearby swimming pool.Duringmaintenance,2ndheatexchangercanallowthe operation.Werecommendtodesignheatexchangernearswimming poolbasedon40℃ inlettemp.(Originally,inlettemp.was 38℃)
Forthewaterpipesystem,weusedaclosedlooptype.
REFERENCES [1] TheThermalRegulationofConstructionin tisation.pdffiles/guide%20chaffage%20ventilation%20et%20cilmahttps://www.amee.ma/sites/default/files/inlineMorocco [2] 2019ASHRAEHANDBOOKHeating,Ventilating,andAir ConditioningApplications [3] LGMULTIVWaterproductDatabook [4] LGMULTIVproductDatabook
4. ROI calculation
The annual average consumption during two years is approximately204,262kW
5. CONCLUSION
Verylow temperaturegeothermalenergyinMoroccoallows the production of thermal energy in a sustainable way. Indeed,theinstallationofgeothermalheatpumpsinsteadof boilersgivesusareturnoninvestmenttimegenerallyless than2years.
Theair waterheatpumpisasystemthatreliesontheuse ofcaloriescontainedintheoutsideairtoheatthewaterthat ispresentintheheatingnetwork. Wehave5outdoorunits,theheatoutputofeachoutdoor unitis63kW.[4]
The investment cost including equipment, installation andmaintenanceis:2000000MAD Thegainininvoicein1year:1049775.31MAD/year Paybacktime(ROI)isapproximately1.9years(22.86 months)
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p ISSN: 2395 0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page260
For the ground heat source heat pumps, the heat is taken fromawell,thisheatisthentransferredbytheheatpump tothehotwatercircuitoftheheatinginstallation. We have2 outdoor units,theheatoutputof eachoutdoor unitis63kW.[3]
TheaveragepriceofelectricityinMoroccoisabout1.1 MAD/kWh Thepricepaidforoneyearis:224688.2MAD