AS/NZS 4234:2008 Australian/New Zealand Standard Heated water systemsCalculation of energy consumption AS/NZS 4234:2008 AS/NZS 4234:2008 ThisJointAustralian/NewZealandStandardwaspreparedbyJointTechnical CommitteeCS-028,Solar WaterHeaters. Itwasapproved onbehalfoftheCouncil ofStandardsAustraliaon25July2008andonbehalfoftheCouncilofStandards New Zealand on 28 July 2008.This Standard was published on 21 August 2008. The following are represented on Committee CS-028: Australian Chamber of Commerce and Industry Australian Electrical and Electronic Manufacturers Association Australian Industry Group Australian and New Zealand Solar Energy Society Chartered Institution of Building Services Engineers Department of Energy, Utilities and Sustainability (NSW) Energy Efficiency and Conservation Authority of New Zealand Gas Appliance Manufacturers Association of Australia Institution of Professional Engineers New Zealand James Cook University Massey University Master Plumbers, Gasfitters and Drainlayers New Zealand New Zealand Solar Industries Association Office of the Renewable Energy Regulator Sustainability Victoria The University of New South Wales Waikato Institute of Technology Keeping Standards up-to-date Standardsarelivingdocumentswhichreflectprogressinscience,technologyand systems.Tomaintaintheircurrency,allStandardsareperiodicallyreviewed,and neweditionsarepublished.Betweeneditions,amendmentsmaybeissued. Standardsmayalsobewithdrawn.Itisimportantthatreadersassurethemselves theyareusingacurrentStandard,whichshouldincludeanyamendmentswhich may have been published since the Standard was purchased. Detailed information about joint Australian/New Zealand Standards can be found by visitingtheStandardsWebShopatwww.standards.com.auorStandardsNew Zealandwebsiteatwww.standards.co.nzandlookinguptherelevantStandardin the on-line catalogue. Alternatively,bothorganizationspublishanannualprintedCataloguewithfull detailsofallcurrentStandards.Formorefrequentlistingsornotificationof revisions,amendmentsandwithdrawals,StandardsAustraliaandStandardsNew Zealandofferanumberofupdateoptions.Forinformationabouttheseservices, users should contact their respective national Standards organization. WealsowelcomesuggestionsforimprovementinourStandards,andespecially encouragereaderstonotifyusimmediatelyofanyapparentinaccuraciesor ambiguities.PleaseaddressyourcommentstotheChiefExecutiveofeither StandardsAustraliaorStandardsNewZealandattheaddressshownontheback cover. This Standard was issued in draft form for comment as DR 07274. AS/NZS 4234:2008 Australian/New Zealand Standard Heated water systemsCalculation of energy consumption COPYRIGHT Standards Australia/Standards New Zealand All rights are reserved. No part of this work may be reproduced or copied in any form or by anymeans,electronicormechanical,includingphotocopying,withoutthewritten permission of the publisher. Jointly published by Standards Australia, GPO Box 476, Sydney, NSW 2001 and Standards New Zealand, Private Bag 2439, Wellington 6020 ISBN 0 7337 8872 6 Originated as AS 42341994. Jointly revised and designated AS/NZS 4234:2008. AS/NZS 4234:20082 PREFACE ThisStandardwaspreparedbytheStandardsAustraliaCommitteeCS-028,SolarWater Heaters to supersede AS 42341994. The performance evaluation procedure defined in this Standardhasbeendesignedtoprovideameansofevaluatingtheannualtaskperformance of heated water systems. Testingofsolarandheatpumpwaterheatingsystemsunderoutdoorconditionshasbeen definedinAS 2984,SolarwaterheatersMethodsoftestforthermalperformanceOutdoortestmethod.Outdoortestingrequiresalongtestperiod(810weeks)duetothe needtoobtainstableinputsforarangeofoperatingconditions.Themajordrawbackof outdoor testing is that the tests must be repeated for every variation of system configuration offered by the supplier. The procedure defined in this Standard overcomes the time and cost limitations of using the outdoor test standard AS 2984. Theperformanceevaluationsarebasedonmodellingannualperformanceinarangeof climaticconditionsusingtheTRNSYSsimulationprogram.TRNSYSisspecifiedasthe modellingpackagebecauseofitsflexibilityandcapacitytomodelthewiderangeof renewable energy water heaters used in Australia and New Zealand.Itisthecommittee'sintentionthatdeterminationofthestandardizedannualenergyusefor productssuchasair-sourceheatpumpsandintegralsolarwaterheaters(combinedsolar collectorandstoragetank)willbeaddedtothisStandardbyamendment.Interimtest procedures for these products may be accepted by rating authorities. ThetermsnormativeandinformativehavebeenusedinthisStandardtodefinethe application of the appendix to which they apply. A normative appendix is an integral part of a Standard, whereas an informative appendix is only for information and guidance. 3AS/NZS 4234:2008 CONTENTS Page SECTION 1SCOPE AND GENERAL 1.1SCOPE ........................................................................................................................ 4 1.2APPLICATION........................................................................................................... 4 1.3REFERENCED DOCUMENTS .................................................................................. 5 1.4DEFINITIONS ............................................................................................................ 6 1.5NOTATION ................................................................................................................ 8 SECTION 2INPUT PARAMETERS 2.1INTRODUCTION..................................................................................................... 10 2.2COMPONENT TESTING......................................................................................... 10 2.3COLLECTOR EFFICIENCY CORRECTION FOR SHADOWING DUE TO IMPACT GUARD..................................................................................................... 12 2.4WATER HEATER CONFIGURATION.................................................................... 13 SECTION 3PERFORMANCE EVALUATION 3.1STANDARDIZED ANNUAL TASK PERFORMANCE........................................... 14 3.2WEATHER DATA.................................................................................................... 14 3.3THERMAL ENERGY LOADS ................................................................................. 14 3.4MINIMUM SOLAR PERFORMANCE .................................................................... 14 3.5WATER TEMPERATURE........................................................................................ 15 3.6COLD WATER INLET TEMPERATURE................................................................ 15 3.7PUMPED CIRCULATION CONTROL IN SOLAR WATER HEATERS ................ 15 3.8TRNSYS DECK SETUP FOR MODELLING THERMAL STRATIFICATION IN STORAGE TANKS................................................................................................... 16 3.9PIPING CONFIGURATION FOR SOLAR WATER HEATERS.............................. 17 3.10ENERGY CONSUMED FOR FREEZE PROTECTION OF SOLAR WATER HEATERS................................................................................................................. 18 3.11OVER-TEMPERATURE CONTROL....................................................................... 18 3.12MODELLING GAS STORAGE WATER HEATERS............................................... 19 3.13MODELLING INSTANTANEOUS GAS WATER HEATERS ................................ 19 3.14PRESENTATION OF RESULTS.............................................................................. 20 APPENDICES ASTANDARD OPERATING CONDITIONS FOR DOMESTIC WATER HEATING IN AUSTRALIA ....................................................................................................... 21 BSTANDARD OPERATING CONDITIONS FOR DOMESTIC WATER HEATING IN NEW ZEALAND................................... 27 CSTANDARD OPERATING CONDITIONS FOR DOMESTIC WATER HEATING IN NEW ZEALAND................................... 27 DCORRECTIONS FOR EFFECT OF HAIL GUARDS ON SOLAR COLLECTOR EFFICIENCY................................................................ 46 EWATER HEATER TASK PERFORMANCE EVALUATION.................................. 48 FPERFORMANCE RESULT...................................................................................... 52 GRENEWABLE ENERGY CERTIFICATES FOR GAS BOOSTED PRODUCTS..... 55 AS/NZS 4234:20084 COPYRIGHT STANDARDS AUSTRALIA/STANDARDS NEW ZEALAND Australian/New Zealand Standard Heated water systemsCalculation of energy consumption S E C T I O N 1 S C O P E A N D G E N E R A L1.1 SCOPE ThisStandardsetsoutamethodofevaluatingtheannualenergyperformanceofwater heatersusingacombinationoftestresultsforcomponentperformanceandamathematical modeltodeterminethestandardizedannualpurchasedenergyuse.Theprocedureis applicable to electric, gas and solar water heaters with integral boosting or preheating into a conventionalstorageorinstantaneouswaterheaterandtoheatpumpwaterheaters.For solarandheatpumpwaterheaters,displacedpurchasedenergyrelativetoreferencewater heaters is also calculated. Solar and solar boosted heat pump water heater types not covered intheapplicationofthisStandardcanbetestedunderAS 2984toobtainanannual performance assessment. TherearenoproductdesignoroperationrequirementsinthisStandard.Systemoperating parameters specified in this Standard are only for the purpose of performance modelling.1.2 APPLICATION TheprocedureinthisStandardusesamathematicalmodeltoassessannualenergy,hence theapplicationoftheprocedureisrestrictedbytheavailabilityofsuitablemathematical models.TheanalysisrequiredbythisStandardshallbebasedontheTRNSYSsimulation model (version 15 or later) with modifications to suit typical packaged solar and heat pump waterheaters.TheTRNSYSsoftwarepackageisavailablefromTheUniversityof Wisconsin (see Appendix E). Weather data and typical modelling data files (TRNSYS deck files)aresuppliedwiththisStandard.Theoperatingconditionsandproductconfigurations tobeusedforevaluatingtheenergyperformanceofawaterheaterarealsodefinedinthis Standard. This Standard may be applied to the following water heaters: (a)Electric and gas storage water heaters. (b)Electric and gas instantaneous heaters. (c)Solar water heaters with (i)flat plate, concentrating or evacuated tubular solar collectors; (ii)thermosiphon or pumped fluid circulation through the solar collectors;(iii)collector loop heat exchangers in a thermosiphon loop;(iv)horizontal or vertical water storage tanks;(v)storage tanks with single or dual electric element(s);(vi)storage tanks with internal gas boosting; and(vii)storage tanks with delivery side heat exchangers.(d)Solar preheaters in series with electric or gas storage or instantaneous boosters. 5AS/NZS 4234:2008 COPYRIGHT (e)Solar boosted heat pump water heaters with(i)solar collectors acting as the refrigerant evaporator; (ii)water cooled condenser; and(iii)in-tank electric booster. NOTE: Airsourceheatpumpwaterheaterswillbeaddedtothislistbyamendmenttothis Standard when the development method is completed. AninterimmethodologyisavailablefromOfficeoftheRenewableEnergyRegulator (ORER)inAustraliaandEnergyEfficiencyandConservationAuthority(EECA)inNew Zealand. Example deck files for the following systems are provided with this Standard. (A)Thermosiphon solar water heaters with in-tank supplementary boosting. (B)Pumped solar water heaters with in-tank supplementary boosting. (C)Thermosiphon solar pre-heater in series with an instantaneous gas booster. (D)Pumped solar pre-heater in series with an instantaneous gas booster. (E)Electric storage water heater. (F)Gas storage water heater. (G)Gas instantaneous water heater. NOTE: Sample decks are suitable for modelling both flat plate and evacuated tube collectors. Otherwaterheaterconfigurationsincorporatingtheabovecomponentsmayalsobe modelled.IfitisnotpossibletomodeltheproductusingtheTRNSYSsoftwarethenthe product may be rated using AS 2984. 1.3 REFERENCED DOCUMENTS The following documents are referred to in this Standard: AS 1056Storage water heaters 1056.1Part 1: General requirements 2984SolarwaterheatersMethodoftestforthermalperformanceOutdoortest method 3498AuthorizationrequirementsforplumbingproductsWaterheatersandhot-water storage tanks 4552Gas fired fuel water heaters for hot water supply and/or central heating AS/NZS 2535Test methods for solar collectors 2535.1Part 1:Thermalperformanceofglazedliquidheatingcollectorsincluding pressure drop (ISO 9806-1:1994, MOD) 2712Solar and heat pump water heatersDesign and construction 4692Electric water heaters 4692.1Part 1:Energy consumption, performance and general requirements NZS 4602Low pressure copper thermal storage electric water heaters 4606Storage water heaters 4606.1Part 1:General requirements AS/NZS 4234:20086 COPYRIGHT ISO 9806Test methods for solar collectors 9806-3Part 3:Thermalperformanceofunglazedliquidheatingcollectors(sensible heat transfer only) including pressure drop ASHRAE 23-93Methods of testing for rating positive displacement refrigerant compressors andcondensing units 1.4 DEFINITIONS For the purpose of this Standard, the definitions below apply. 1.4.1 Absorber Devicewithinacollectorforabsorbingradiantenergyandtransferringthisenergyasheat into a fluid. 1.4.2 Auxiliary equipment Thosepartsofasolarorheatpumpwaterheatersystemthatusepurchasedelectrical energy,otherthanresistiveheatingunitsorheatpumppackage(compressorandintegral controls, pumps and fans). 1.4.3 Collector Device containing an absorber and intended for installationeitheras aunit oraspart of an array of units. 1.4.4 Collector aperture Thenetareaavailablefortransmissionofsolarradiationthroughtheouterair/cover interface;forunglazedcollectors,thenetplanareaoftheabsorber.Theaperturewidthfor different collector types is illustrated in AS/NZS 2535.1. 1.4.5 Collector inclination Angle between aperture surface of the collector and the horizontal. 1.4.6 Container Vesselincludingfittings,inwhichtheheatedwaterisstored;sometimesreferredtoasa storage container, cylinder or tank. 1.4.7 Dual elements Electricelementsatdifferentlevelsinthetank.Eachelementmaybeconnectedtoa different electric supply or be operated under local control. 1.4.8 Electricity supply options 1.4.8.1 Continuous Continuously available electricity supply. 1.4.8.2 Limited time of supply Electric supply available at limited times, as follows: (a)Nightrate Electricitysupplyatrestrictednighthours.(SeeAppendices AandBfor typical availability times.) (b)Extended off-peak Electricitysupply duringextended hours. (See Appendices Aand B for typical availability times.) 7AS/NZS 4234:2008 COPYRIGHT 1.4.9 Evacuated tubular collector Evacuatedcollectoremployingtransparenttubing(usuallyglass)withanevacuatedspace betweenthetubewallandtheabsorber.Theabsorbermayconsistofaninnertubeor another shape, with means for removal of the thermal energy. 1.4.10 Heat pump water heater Awaterheaterusingvapourcompressioncycleandincorporatingacompressor,an evaporator and a condenser that delivers heat to the water either directly or indirectly. 1.4.10.1 Heat pump water heatersolar boosted Aheatpumpwaterheaterwithanevaporatorcollectingenergyfromlatentandsensible heat of the atmosphere and solar radiation. 1.4.10.2 Heat pump water heaterair source Aheatpumpwaterheaterwithanevaporatorcollectingenergyfromlatentandsensible heat of the atmosphere. 1.4.11 Incidence angle Angle between the direct radiation and the outward normal from the plane considered (e.g., from the collector aperture). 1.4.12 Irradiance Power density of radiation incident on a surface, i.e. the quotient of the radiant flux incident on the surface and the area of that surface, or the rate at which radiant energy is incident on a surface per unit area of the surface (Unit: W/m2). 1.4.13 Irradiation Theincidentenergyperunitareaofasurface,foundbyintegrationofirradianceovera specified time interval, often an hour or a day (Unit: MJ/m2 per specified time interval). 1.4.14 Load Amount of thermal energy drawn from the system as hot water. Energy is computed relative to the cold-water inlet temperature. 1.4.15 One-shot boosting Operationofasupplementaryheatsourceforoneheatingcycle.Theheaterisreturnedto normal control after one heating cycle 1.4.16 Packaged system Asystemwithafixedconfiguration,soldasaready-to-installkitcontainingallsystem components. 1.4.17 Reference water heater Aconventionalwater heater used todefine annual purchased energyuse for thepurpose of computing energy savings of other products. 1.4.18 Standardized annual energy useTheannualpurchasedenergyuseofawaterheater,operatingunderspecifiedreference weather and load conditions. 1.4.19 Sidearm heat exchangerAheatexchangerexternaltothestoragetankthattransfersheatfromahydrauliccircuit including the solar collectors to a separate hydraulic circuit that includes the storage tank. AS/NZS 4234:20088 COPYRIGHT 1.4.20 Supplementary energy Gas or electrical energy used by a solar or heat pump water heater to directly heat the water by a gas burner, electrical resistive heating unit and/or heat pump package (compressor and integral controls, pumps and fans). 1.4.21Tank nodes Horizontalsectionsofastoragetankwherethefluidtemperatureisconsideredtobe constant. Used in the simulation program to model thermal stratification in the storage tank. 1.4.22 Tank modelling options 1.4.22.1 Fixed inlet position Fluidflowsintothestoragetankareconsideredtomixwiththecontentsofthetanknode immediately level with the inlet fitting. 1.4.22.2 Variable inlet position Fluidflowsintothestoragetankareconsideredtoriseorfalltothelevelofthetanknode with the closest temperature to the inlet flow. 1.4.23 TRNSYS deck Input data file for the TRNSYS software describing system components to be modelled and simulation parameters. 1.5 NOTATION Symbols used in this Standard are listed below. a,b,c=correlation coefficients for solar collector efficiency Br=annual purchased energy used by the reference water heater (MJ/y) Be=annual electrical energy used by auxiliary equipment (MJ/y) BS=annual supplementary energy for a solar or heat pump water heater (MJ/y) en=electrical power use during gas burner operation (W) esm=electrical power use during standby (W) E=thermal efficiency of gas water heater (%) fR=purchased energy savings relative to the reference water heater Gb=beam irradiance on the collector aperture (W/m2) GL=relative long wave irradiance ( > 3 m) = 4aT GS (W/m2) GS=long wave thermal irradiance ( > 3 m) (W/m2) GT=total solar irradiance on the collector aperture (W/m2) H=heat output of a gas water heater (kW) K=solar collector incident angle modifier KNS, KEW=bi-axial incidence angle modifiers M=maintenance rate (MJ/h) N=number of startup events in an instantaneous gas water heater P=Pilot flame gas consumption for instantaneous gas heater (MJ/h) R=determined gas consumption (MJ/h) 9AS/NZS 4234:2008 COPYRIGHT t=duration of test (h) T=collector fluid temperature (C) Ta=ambient temperature (C) Tdb=thermostat dead band (K) w T =mean temperature of water in the storage tank (C) T =mean collector fluid temperature (C) Tset=Thermostat setting (C) Tsky=Sky temperature (C) u=surrounding air speed over the solar collector (or evaporator) (m/s) UA=Tank heat loss coefficient tank inner core surface area (W/K) =unglazed collector hemispherical absorber absorptance, short wave =unglazed collector hemispherical absorber emittance, long wave =solar collector efficiency =incidence angle relative to the collector aperture normal (degrees.) =Stefan-Boltzmann constant (5.67 108 W/m2K4) AS/NZS 4234:200810 COPYRIGHT S E C T I O N 2 I N P U T P A R A M E T E R S2.1 INTRODUCTION ThisStandarddefinesameansofevaluatingthepurchasedenergyuseofwaterheaters operating under specified weather and load conditions. Forproductsthatconnecttoorincludeelectricorgasstoragewaterheatersactingas boosters the procedure builds on data obtained from Standards AS/NZS 4692.1, AS 1056.1, NZS 4602, NZS 4606.1 and AS 4552. Forlimitedtime-of-supplyelectricstoragewaterheatersthetemperaturestratificationin thestoragetankisevaluatedthroughoutthedayandusedtoquantifythevariationoftank heatlosswithtime,duetocoolingofthebottomofthetank.Mixingduringloaddrawoff andconductionbetweenthehotandcoldlayersinthetankisalsoincluded.Allelectric boostedandun-boostedstoragetanksshallberatedforstandingheatlossunder AS/NZS 4692.1,AS 1056.1,NZS4602orNZS4606.1.Allgasboostedstoragetanksshall beratedformaintenancerateunderAS 4552.Theoperationalheatlossdeterminedbythe annualperformance simulationmodel accounts fornon-uniforminsulation thickness on the top and sides of the tank and thermal stratification in the tank. For solar water heaters this Standard is limited to systems capable of being separated into a solarcollectorcomponentandastoragevesselcomponent.Theperformanceofthese componentsisevaluatedunderStandardsAS/NZS 2535.1,AS 4552,AS/NZS 4692.1and AS 1056.1. Theperformanceofheatpumpwaterheaterswithevaporatorsexposeddirectlytosolar radiationisevaluatedusingtestresultsfortheevaporatorevaluatedunderAS/NZS 2535.1 foraglazedevaporatororISO 9806-3foranunglazedevaporatorandperformanceofthe compressor evaluated under ASHRAE 23-93. 2.2 COMPONENT TESTING 2.2.1 Electric boosted, un-boosted and heat pump storage tanksForelectricboosted,un-boostedandheatpumpstoragetanksthefollowingperformance factors shall be evaluated: (a)The standing heat loss, using AS 1056.1, AS/NZS 4692.1, NZS 4602 or NZS 4606.1. (b)The volumetric capacity.(c)Fordisplacementtypewaterheaters,thehotwaterdeliveryusingAS 1056.1or AS/NZS 4692.1. Toseparatethefunctionsofsolarheatingandsupplementaryboosting,boostersinwater heater storage tanks may be located above the bottom of the tank or tanks may be designed withnointernalboosting.Evaluationofthestandinglossandhotwaterdeliveryofsuch tanks requires a test with a special electric element fitted in the bottom of the tank to ensure heating of the entire contents of the tank as specified in AS/NZS 4692.1. 2.2.2 Gas boosted storage vessels The following performance factors shall be evaluated using the test methods in AS 4552: (a)Thermal efficiency (%). (b)Heat output (kW). (c)Maintenance rate (MJ/h). 11AS/NZS 4234:2008 COPYRIGHT (d)Electric power usage during standby (W). (e)Electric power usage during burner operation (W). (f)Tank volumetric capacity (L).Heat loss from storage tanks incorporating raised level gas boosting from either an internal orexternalburnershallbedeterminedbydirectmeasurementusingaspeciallyconfigured tankthatismaintainedatuniformtemperatureduringheatlosstesting.Aspecialelectric elementinstalledforthepurposeoftheheatlosstestasspecifiedinAS/NZS 4692.1shall be an acceptable method. 2.2.3 Instantaneous gas water heaters The following performance factors shall be evaluated using the test methods in AS 4552. (a)Thermal efficiency (%). (b)Heat output (kW). (c)Pilot gas consumption (MJ/h). (d)Start-up heat capacity (MJ/event). (e)Electric power usage during standby (W). (f)Electric power usage during burner operation (W). 2.2.4 Solar boosted heat pump storage water heaters Theheatpumpcompressorthermalcapacityandpowerconsumption shallbeevaluatedfor evaporatorrefrigeranttemperaturescoveringtherangefrom5Cto30C(atleastfour temperatures) and condenser refrigerant temperatures covering the range from 30C to 70C (at least four temperatures) using the test procedure in ASHRAE 23-93. 2.2.5 Flow rate in pumped collector-loops 2.2.5.1 Constant speed pumps The flow rate in pumped circulation systems shall be measured in a systemassembled with 10 mofpipelengthofthemanufacturersspecifieddiametereachwaybetweenthetank andthecollectorarray.Forsystemswithsitespecificflowadjustment,theflowcontrol device specified by the manufacturer for this piping length shall be installed. 2.2.5.2 Variable speed pumpsThe flow rate in pumped circulation systems incorporating a pump speed controller shall be measured over the complete range of the control parameter variation in a system assembled with10 mofpipelengthofthemanufacturersspecifieddiametereachwaybetweenthe tank and the collector array. 2.2.6 Solar collector efficiency TheefficiencyofglazedsolarcollectorsshallbeevaluatedusingAS/NZS 2535.1.The efficiencyofunglazedsolarcollectors(orsolarboostedheatpumpevaporators)shallbe evaluated using ISO 9806-3. The collector efficiency shall be characterized using the following equations: Glazed flat plate collectors: = T T) (GT TaGT Ta a23 2 1a a. . . 2.1AS/NZS 4234:200812 COPYRIGHT Concentrating collectors: = b2a3ba2 1) (GT TaGT Ta a . . . 2.2Evacuated collectors: = ( )T4a43Ta2 1) 273 ( ) 273 (GT TbGT Tb b+ + . . . 2.3Unglazed collectors: = L Ta3 2 1) (G GT Tu c c c++ . . . 2.4ThecoefficientsinEquations 2.1,2.2,2.3and2.4havepositivevalues.Negative coefficients shall not be accepted in the calculations in this Standard. ThesolarcollectorareausedwithEquations 2.1,2.2,2.3or2.4shallbethevalueusedin determination of the coefficients by the solar collector test laboratory. Equation 2.3isthepreferredfunctionforevacuatedtubularcollectors,however, Equation 2.1 is acceptable if the test data from the solar collector test report is not available for the purpose of computing the coefficients in Equation 2.3. 2.2.7 Incidence angle modifier 2.2.7.1 General The incidence angle modifier shall be measured as specified in AS/NZS 2535.1. 2.2.7.2 Flat plate collectorsFlatplatecollectorswithasingleglasscoverandcovertoabsorberspacinglessthan 40 mm may use a default incidence angle modifier of d = 0.06 in Equation 2.5. K= 1cos11d . . . 2.5where =incidence angle relative to the collector aperture normal 2.2.7.3 Evacuated tubular collectors Biaxialincidenceanglemodifiersforevacuatedtubecollectorsshallbeused.Valuesfor bothtransverseandlongitudinalincidenceanglemodifiersshallcovertheincidenceangle rangefrom0to90.Bothmodifiersshallbe1at0and0at90.Ifmeasuredbiaxial opticaldataforanevacuatedtubearrayisnotavailablethenthedefaultincidenceangle coefficient (d = 0.06) in equation 2.5 shall be used. NOTE: Incidenceangleeffectsforflatplatecollectorsreducethedailyoutputasindicatedby Equation 2.5. Incidence angle effects for some evacuated tube collectors increase the daily output, henceapplicationofthedefaultincidencemodifier(Equation 2.5withd = 0.06)toanevacuated tube collector may result in a performance penalty. 2.3 COLLECTOREFFICIENCYCORRECTIONFORSHADOWINGDUETO IMPACT GUARD If an impact guard is added to a collector after the collector efficiency test then the collector efficiency shall be corrected for 13AS/NZS 4234:2008 COPYRIGHT (a)normal incidence shadowing due to the impact guard; and (b)incidence angle modifier of impact guard as specified in Appendix D. 2.4 WATER HEATER CONFIGURATION ThesystemconfigurationdatalistedinAppendix Cshallbeusedinthemodelling.Additional data may be needed for some systems. ThesolarcollectorinclinationandazimuthshallbeasspecifiedinAppendix Afor Australia or as in Appendix B for New Zealand. Oneofthefollowingsupplementaryboostsupplyandcontroloptionsshallbespecifiedin the performance model: (a)Electricin-tankboosting(continuousortimelimitedsupply)includingdualelectric elements with each element operated on different electric supply options. (b)Gas in-tank boosting. (c)Gas or electric storage water heater in series with solar or heat pump preheater. (d)Series instantaneous booster with the solar heater operating as a preheater. NOTE: Thetimingofelectricalsupplementaryboostingmaybesettonightratetarifftimes, extendedoff-peaktimes,continuousboostingorsetbyalocalcontroller.Thesupplementary boostcontrollermayvarysupplementaryinputtothetankinresponsetosolarradiation conditions, stored energy level in the tank, load demand and other conditions. Iftheelectricsupplyutilityallowsuseractivationofone-shotboostingintimelimitedelectric tanks then the effect of this may be modelled as part of the annual performance evaluation. User over-ride of supplementary boosting shall not be included in the modelling. AS/NZS 4234:200814 COPYRIGHT S E C T I O N 3 P E R F O R M A N C E E V A L U A T I O N3.1 STANDARDIZED ANNUAL TASK PERFORMANCE The mathematical model to be used for the standardized annual energy use evaluation shall betheTRNSYSsimulationprogram(version15orlater)withmodificationsoutlinedin Appendix D. The standardized annual energy use of water heaters shall be determined using the TRNSYS simulationprogramwithacomputationaltimestepof0.1 hoursorlesstodeterminethe annual purchased energy use for the specified load and environmental conditions. 3.2 WEATHER DATA TheweatherdatausedforthesimulationshallbeTypicalMeteorologicalYearrecordsfor thelocationsspecifiedinAppendix AorB.Theperformanceshallbebasedonhourly values for the following variables: Ambient temperature(all systems) Global horizontal irradiation(solar water heaters and solar-boosted heat pumps) Beam irradiation(solar water heaters and solar-boosted heat pumps) Wet bulb temperature(heat pumps only) Wind speed(solar-boostedheatpumpsandsolarwaterheaters incorporating unglazed collectors) Cloud cover(solar-boostedheatpumpsandsolarwaterheaters incorporating unglazed collectors) 3.3 THERMAL ENERGY LOADS Thepeakdailythermalenergyloadsandseasonalanddailyvariationsofloadspecifiedin Appendix A or B shall be used for the annual energy use evaluation. The load is distributed withineachdayusingthedailyloadpatternandtheloadisvariedeachmonthusingthe seasonal loadpattern. The TRNSYS simulation deckshallbe configured sothat the load is specifiedintermsofenergywithdrawnafterthetemperingvalveinthemannershownin the example TRNSYS simulation deck files (Appendix E). Themanufacturershallselectaloadsuchthatthesystemperformancesatisfies Clauses 3.5.2 and 3.4. 3.4 MINIMUM SOLAR PERFORMANCEForallzonesinAustralia,ifalargeormediumloadisselectedfromTableA3,when modelledinzone3thesystemshallachieveaminimumof60%annualenergysaving relative to reference water heater of same boost fuel type supplying the same specified load.For allzones inNewZealand, if amediumload isselected from TableB3, whenmodelled inzone5thesystemshallachieveaminimumof50%annualenergysavingrelativeto reference water heater of same boost fuel type supplying the same specified load . If a large loadisselectedfromTableB3whenmodelledinzone5thesystemshallachievea minimum of 60% annual energy saving relative to reference water heater of same boost fuel type supplying the same specified load. NOTE: Small systems are not required to meet these requirements. 15AS/NZS 4234:2008 COPYRIGHT 3.5 WATER TEMPERATURE 3.5.1Control of temperature Themodelshallsimulatethetemperaturecontrolstrategythatisprogrammedintoany controller and/or recommended in manufacturers instructions. NOTE: Thetemperaturecontrolstrategyofasolarwaterheatersystemshouldcomplywith AS 3498, when the system is intended to be installed in Australia and with clause G12 of the New Zealand Building Code, when the system is intended to be installed in New Zealand. 3.5.2 Minimum delivery temperature Thesystemshallbecapableofsatisfyingaminimumdeliverytemperatureof45Cduring thesimulationtocalculatethestandardizedannualenergyuseattheselectedloadforall selected zones. Asystemthat satisfies theminimumdelivery temperature requirement inzone4 isdeemed to satisfy the requirement in all Australian zones.Asystemthat satisfies theminimumdelivery temperature requirement inzone6 isdeemed to satisfy the requirement in both New Zealand zones. NOTE: Ifasystemfailstomeettheminimumdeliverytemperature of45Cthenitmayberated foralowerloadprovideditcansatisfytheminimumdeliverytemperaturerequirementforthe lower load. 3.6 COLD WATER INLET TEMPERATURE Themonthlycold-waterinlettemperatureprofilesspecifiedinAppendix AorBshallbe used. 3.7 PUMPED CIRCULATION CONTROL IN SOLAR WATER HEATERS 3.7.1 General Ifthestoredpotablewaterispumpedthroughthesolarcollectororanexternalheat exchangerthenthecirculationflowratemayhaveasignificanteffectonthermal stratificationinthestoragetank.Stratificationimprovesperformancebymaximizingthe deliverytemperatureandminimisingthecollectorinlettemperature.Theeffectofahigh flow-ratemaybeparticularlysignificantinsingletanksystemswhereasupplementary boosterheatsthetopsectionofthetank.Ifthepumpedloopreturnleveltothetankis belowthelevelofthein-tanksupplementaryheaterthendisturbanceofthermal stratification due to pumped circulation through the storage tank can be minimized by using a low flow rate. 3.7.2 Low-flow criteria For pumped circulation solar water heaters, low-flow criteria shall be as follows: (a)The flow rate through the collectors is less than 0.75 L/min/m2 of collector aperture. (b)Thecollectorflowreturnleveltothetankisbelowthelevelofthesupplementary booster where fitted. (c)The pump control or pressure drop is adjusted to suit the suit the collector array size, pipe lengths and fittings for each installation. Criteria (c) may be achieved by one of the following methods: (i)Installationofaflowindicatorandvalvesothattheflowratecanbeadjustedonsite for each installation (depending on piping lengths and collector size). (ii)Installation of a pre-sized orifice restrictor to suit the pump, pipe length and collector area of the particular installation. AS/NZS 4234:200816 COPYRIGHT (iii)Installationofaprogrammablecontrollerthatsetstheflowrateortemperaturerise across the collectors to suit the installation and operating conditions. (iv)Some other equivalent site-specific flow control method. 3.7.3 Controlled-flow pumped-circulation Pumpedcirculationsolarwaterheatersthatsatisfythelow-flowcriteriashallusethe controlled-flowthermalstratificationrequirementsinClause 3.8.2fortheannual performance simulation. 3.7.4 Uncontrolled-flow pumped circulation Pumpedcirculationsolarwaterheatersthatdonothavesitespecificadjustmentorcontrol ofcollectorloopflowrateshallusetheuncontrolled-flowthermalstratification requirements in Clause 3.8.4 for the annual performance simulation. 3.7.5 External collector loop heat exchanger systems Solarwaterheatersusingapumpedcollectorloopworkingthroughasidearmheat exchangerwithathermosiphonlooponthetanksideoftheheatexchangershallusethe thermosiphoncirculationthermalstratificationrequirementsinClause 3.8.3fortheannual performance simulation. 3.7.6 Pump controllers TheTRNSYSdeckshallmodeltheoperationofpumpcontrollersthatsenseflowrate, collectortemperatureriseorotherreal-timevariablesinordertosettheflowrateinthe collector-loop or sidearm-loop. 3.8 TRNSYSDECKSETUPFORMODELLINGTHERMALSTRATIFICATIONIN STORAGE TANKS 3.8.1 General Thermalstratificationinasolarheatedstoragetankdependsontheflowratebetweenthe tankandthesolarcollectororcollectorloopheatexchanger.Thermalstratificationinthe storagetankshallbemodelledasmixedfloworstratifiedflowusingthefollowingsystem classifications. 3.8.2 Controlled flow-rate pumped circulation Forstoragetankswithpumpedcirculationthatsatisfiesthelow-flowcriteriathermal stratification shall be modelled using the following options in the TRNSYS deck: (a)Site specific flow rate specified by the manufacturer or set by the controller. (b)Variable inlet position mixing option in the software model of the tank. (c)20ormoretanknodesinafixednodetankmodelortheautomaticnodeTYPE138 model. NOTE: Toaccuratelymodelthermalstratificationincontrolledflowpumpedsystems,20tank nodes is normally sufficient. 3.8.3 Thermosiphon circulation For storagetanks with thermosiphon circulation fromthe collectorsor fromasidearmheat exchangerthermalstratificationshallbemodelledusingthefollowingoptionsinthe TRNSYS deck: (a)Variable inlet position mixing option in the software model of the tank. (b)Twentyormoretanknodesinafixednodetankmodelortheautomaticnode TYPE145 thermosiphon system model. 17AS/NZS 4234:2008 COPYRIGHT 3.8.4 Uncontrolled flow-rate pumped circulation For storage tanks with pumped circulation that does not satisfy the low-flow criteria (either directlyfromthecollectorsorfromaside-armheatexchanger)mixingshallbemodelled using the following options in the TRNSYS deck: (a)Measuredcollectorloopflowrateor1.0 L/min/m2ofcollectoraperturearea,which ever is larger. (b)Fixed inlet position mixing option in the software model of the tank. (c)Maximumof10 tanknodesinafixednodetankmodelortheautomaticnode TYPE138 tank model. NOTE: Uncontrolled flow pumped systems may not achieve good thermal stratification, hence the number of nodes is limited to 10. 3.8.5 Heat exchanger tanks Forstoragetankswithinternal,wrap-around,ormantle(tank-in-tank)heatexchangers thermal stratification shall be modelled using the following options in the TRNSYS deck: (a)Variable inlet position mixing option for the tank. (b)20ormoretanknodesinafixednodetankmodelortheautomaticnodeTYPE138 tank model. 3.9 PIPING CONFIGURATION FOR SOLAR WATER HEATERS 3.9.1 Collector loop piping The length of piping between the storage tank and solar collectors shall be: (a)Pumpedcirculationsystemorremotethermosiphonsystem Pipelengthof10 m (each way) and the manufacturers recommended diameter. (b)Packaged thermosiphon circulation system Manufacturers pipe length and diameter specifications. 3.9.2 Collector loop piping insulation Heat loss from the piping shall be computed for (a)manufacturers specified insulation jacket diameter; (b)thermal conductivity of specified insulation material; (c)external convective heat transfer coefficient (ho) of 20 W/(m2K); and (d)internal convective heat transfer coefficient (hi) of 1000 W/(m2K). Thepipeheatlosscoefficient(Upipe)foraninsulatedpipe,basedonthepipediameter,is given by: Upipe= oio1)i/o( n 12ii11ddhd dkdh+ + (W/m2K). . . 3.1where di=pipe diameter (m) do=outer diameter of the insulation di + twice thickness of insulation (m) k= thermal conductivity of the insulation material (W/m.K) For a metal pipe without insulation the pipe heat loss coefficient Upipe is 20 W/m2K. AS/NZS 4234:200818 COPYRIGHT 3.9.3 Piping between primary storage tank and a series booster 3.9.3.1 Pumped system Ifaseriessupplementaryheaterisnotintegralwiththeprimarystoragetankthepiping betweenapumpedcirculationsolarpreheattankandaseparateseriesconnected supplementary booster shall be modelled as (a)manufacturers maximum length specification or 5 m, whichever is larger; (b)manufacturersmaximumpipediameterspecificationor16 mminternaldiameter when not specified; and (c)manufacturers specified insulation thickness and material. 3.9.3.2 Thermosiphon system Ifthe series boosteris not integralwiththe thermosiphontankthen thepipingbetween the thermosiphon solar preheaterand a separate seriessupplementary boostershallbemodeled as (a)pipe length of 10 m; (b)manufacturersmaximumpipediameterspecificationor16 mminternaldiameter when not specified; and (c)manufacturers specified insulation thickness and material. 3.10 ENERGYCONSUMEDFORFREEZEPROTECTIONOFSOLARWATER HEATERS 3.10.1 Active pumped freeze protection Pumpedcirculationfreezeprotectioninopencircuitsystemsshallbemodelledusingthe same modelling procedure as for day time circulation (Clause 3.8). Thermal energy removed from the tank and electrical energy used by the pump for pumped direct circulation freeze protection of solar collectors shall be included in the calculation of standardizedannual energyuse. Thenight time effective airtemperature used todetermine solarcollectorandpipingheatlossshallbetakenastheaverageofthegroundlevelair temperature (Ta) and the sky temperature Tsky given in Equation 3.2:Tsky=(0.711+0.0056Tdp+0.73 10-4 2dpT )0.25 (Ta+273.15)273.15 (C) . . . 3.2where Tdp=dew point temperature (C) 3.10.2 Electric heater freeze protection Energy used by electric heaters in the collector loop circuit for freeze protection of the solar collectors shall be included in the task performance analysis. 3.11 OVER-TEMPERATURE CONTROL 3.11.1 General Theannualtaskperformanceprogramshallmodelstagnationcontroldeviceswith temperaturesettingsusedtosatisfytheno-loadwaterdumpingrequirementof AS/NZS 2712. 3.11.2 Hot water discharge due to over temperature Temperature-pressurereliefvalveopeningandclosingtemperaturesshallbemodelledas 95C and 88C respectively. 19AS/NZS 4234:2008 COPYRIGHT 3.11.3 Vented system energy dumping Energy loss due to boil-off from vented storage tanks shall be modelled as energy dumping at 100C. 3.12 MODELLING GAS STORAGE WATER HEATERS The efficiency and heat loss from a conventional gas storage water heater shall be modelled using the parameters specified in Clause 2.2.2. The factors required for annual task performance simulation in TRNSYS shall be computed as follows: Tank heat loss rate coefficient UA = 1100EMT . . . 3.3where M =maintenance rate, in MJ/h E =thermal efficiency, percent T =temperature difference during maintenance rate test, in K = 45 K in AS 4552 maintenance rate test 3.13 MODELLING INSTANTANEOUS GAS WATER HEATERS Theefficiencyandstart-upheatcapacityforaninstantaneousgaswaterheatershallbe modelled using the parameters specified in Clause 2.2.3. Thefactorsrequiredforannualtaskperformancesimulationinsimulationdeckshallbe computed as follows Theperformanceofinstantaneousgaswaterheatersisinfluencedbystartupcapacity.The numberofstartupevents(N)tobeusedeachdayforannualperformancesimulationshall be: TABLE 3.13 START-UP HEAT CAPACITY DAILY NUMBER OF STARTUP EVENTS Small load system13 Medium load system19 Large load system26 The number of startup events (N) shall be distributed evenly over all load events. Therefore the number of start up events to be included at each load event shall be N/8 for Australia (8 loadeventsspecifiedinAppendix A)andN/10forNewZealand(10loadeventsspecified in Appendix B). AS/NZS 4234:200820 COPYRIGHT The following energy consumption factors shall be computed: (a)Gas energy consumption rate during burner operation = EE100g(MJ/h). . . 3.4where Eg= energy transfer rate to water from gas combustion (MJ/h) (b)Gas energy consumption rate during standby = P(MJ/h). . . 3.5(c)Additional gas energy consumption rate at each load draw-off event to allow for start-up loss = N/8 S max((TsetTpre)/45.0)(MJ/h)(for zones 1 to 4). . . 3.6= N/10 S max((TsetTpre)/45.0)(MJ/h)(for zones 5 & 6). . . 3.7where Tpre= temperature delivered by the solar pre heater. 3.14 PRESENTATION OF RESULTS 3.14.1 Purchased energy savings relative to reference water heaters The water heater purchased energy saving relative to the reference water heater is: fR= ( ) ( )re S rBB B B + . . . 3.8where Br=annualpurchasedenergyuseofthereferencewaterheaterasspecifiedin Appendix A or B, using the same fuel type and supplying the same load in thesame zone. BS=annual supplementary energy use, for the system being rated. Be=annualelectricalenergyusedbyauxiliaryequipment,forthesystembeing rated. Theannualdisplacedenergy(Br (BS+Be))andtheannualenergysavings(fR)shallbe reported as shown in Appendix F Table F2. 3.14.2 Documentation of simulation model inputs and outputs The report of the simulation results shall include (a)theproduct characteristics and component test results, using theappropriate tables in Appendix C; including test report number, date and test agency; (b)the annual system performance results, in the manner shown in Appendix F; and (c)theTRNSYSdeckfile,outputfileandanycomponentdatafiles(suchasincidence angle modifier data) used in the simulation.21AS/NZS 4234:2008 COPYRIGHT APPENDIX A STANDARD OPERATING CONDITIONS FOR DOMESTIC WATER HEATING IN AUSTRALIA (Normative) A1 SCOPE ThisAppendixspecifiestheenvironmentalandloadconditionstobeusedforthe simulation of domestic hot water demand in Australia. A2 TIME-LIMITED ELECTRIC SUPPLY The following electric boost availability times shall be used: (a)Continuous supply 24 h availability of electricity. (b)Night rate Hours of supply 10 pm to 7 am (a period of 9 h). (c)Extended off-peak Hours of supply 10 pm to 5 pm (a period of 19 h). (d)Locally controlled Electric boosting set by controller supplied by manufacturer. A3 SOLAR COLLECTOR INCLINATION AND ORIENTATION ForAustralianapplicationsTableA1definestwostandardizedcollectorinstallation conditions either of which shall be used to quantify annual performance.TABLE A1 COLLECTOR INCLINATION AND ORIENTATION North orientationRepresentative average installationZone Collector inclination (degrees to horizontal) Collector azimuth (degrees from North) Collector inclination (degrees to horizontal) Collector azimuth (degrees west of North) 1 to 42502045A4 CLIMATE DATA For each zone the Typical Meteorological Year (TMY) data used for the simulation shall be for the location listed in Table A2.TABLE A2 CLIMATE ZONES ZoneTMY data source Latitude degrees Longitude shift from local time longitude degrees Time datumTime at end of first record h 1Rockhampton23.40.48Mean solar time1.5 2Alice Springs23.58.6Mean solar time1.0 3Sydney33.41.2Eastern standard time 1.0 4Melbourne37.85.03Mean solar time1.0 AS/NZS 4234:200822 COPYRIGHT FIGUREA1 CLIMATE ZONES FOR AUSTRALIA A5 HOT WATER THERMAL ENERGY LOADS A5.1 Daily thermal load Peak daily thermal loads in winter are shown in Table A3.TABLE A3 PEAK DAILY THERMAL ENERGY LOADS FOR AUSTRALIA ZoneLarge system peak load MJ/d Medium system peak load MJ/d Small system peak load MJ/d 1453018 2453018 3573822.5 46342 25.2 A5.2 Hourly loads The daily load profiles given in Table A4 shall be used. Each load draw-off shall be applied over a period of 0.1 h. NOTE: This profile is consistent with AS 2984. 23AS/NZS 4234:2008 COPYRIGHT TABLE A4 DAILY LOAD PROFILE FOR AUSTRALIA TimeLoad multiplier Zones 1 to 4 07000.15 08000.15 11000.10 13000.10 15000.125 16000.125 17000.125 18000.125 A5.3 Seasonal load profile The seasonal energy load profiles shown in Table A5 shall be used. TABLE A5 SEASONAL LOAD PROFILE MonthLoad multiplier Zones 1 to 4 January0.70 February0.80 March0.85 April0.90 May0.95 June1.0 July1.0 August1.0 September1.0 October0.95 November0.90 December0.80 Hourly load = Peak daily load seasonal load multiplier daily load multiplier A6 COLD WATER INLET TEMPERATURE Cold-watertemperaturesforeachclimatezoneshowninTable A6shallbeusedasthe water inlet temperature to the storage tank. NOTE: These temperatures are consistent with AS 2984. AS/NZS 4234:200824 COPYRIGHT TABLE A6 COLD WATER TEMPERATURE (C) MonthZone 1Zone 2Zone 3Zone 4 January28292320 February28272320 March27242118 April25201815 May23141511 June2011129 July209118 August21121210 September24181512 October26231915 November28262117 December28282219 A7 CHARACTERISTICS OF REFERENCE WATER HEATERS IN ZONES 1 TO 4 ThecharacteristicsofreferencewaterheatersinAustraliaareshowninTables A7toA9. ThestandingheatlossforelectricstoragesystemsistakenastheMinimumEnergy Performance requirement of AS/NZS 4692.1. TABLE A7 SMALL LOAD REFERENCE ELECTRIC WATER HEATER(CONTINUOUS BOOST)Tank size L Tank heat loss kWh/d Thermostat temperature C Thermostat differential K 801.736510 TABLE A8 MEDIUM AND LARGE LOADS REFERENCE ELECTRICWATER HEATER (NIGHT RATE)Tank size L Tank heat loss kWh/d Thermostat temperature C Thermostat differential K 3152.927510 25AS/NZS 4234:2008 COPYRIGHT TABLE A9 REFERENCE GASWATER HEATER IN AUSTRALIA Product class Tank size L Gas consumption MJ/h Thermal efficiency % Maintenance gas consumption MJ/h Thermostat temperature C Thermostat differential K 3 Star storage 1702878.80.886510 A8 PURCHASEDENERGYOFREFERENCEWATERHEATERSIN ZONES 1 TO 4 TheannualenergyconsumptionofthereferencewaterheatersinAustraliasupplyingthe loadsandloadprofilesdefinedinTables A3,A4,A5andA6isgiveninTable A11.The annualenergyconsumptionwasdeterminedusingthesimulationmethodsoutlinedinthis standard applied to the reference water heaters specified in Tables A7 to A10. TABLE A10 ANNUAL PURCHASED ENERGY CONSUMPTION OF REFERENCE WATER HEATERS IN AUSTRALIA Peak winter daily load MJ/dPurchased energy used MJ/yWater heater type Zones 1 & 2Zone 3Zone 4Zone 1Zone 2Zone 3Zone 4 Electric large load 45576317 18017 26021 10023 140 Electric medium load 30384212 56012 64015 26016 670 Electric small load 1822.525.27 6207 6909 27010 280 Gas large load45576324 99025 21030 40033 240 Gas medium load 30384218 89019 11022 69024 720 Gas small load1822.525.213 69014 19016 41017 930 NOTE: Gas systems use primary energy, whereas electric systems generally use secondary energy. A9 DISPLACED ENERGYA9.1 Electric boosted products Thedisplacedenergyforasolarorheatpumpwaterheatershallbecomputedasshownin Equation A9.1. Displaced energy = [Br (BS + Be)] (MJ) . . . A9.1where Br=annual electrical energy use of reference electric water heater (MJ/y) BS=annualsupplementaryelectricalenergyuseforasolarorheatpumpwater heater (MJ/y) Be=annual electrical energy use by auxiliary equipment (MJ/y) AS/NZS 4234:200826 COPYRIGHT A9.2 Gas boosted products The displaced energy for a solar or heat pump water heater with gas supplementary heating shall be computed as shown in Equation A9.2. Displaced energy = [Br (BS + Be)](MJ). . . A9.2where Br=annual gas energy use of reference gas storage water heater (MJ/y) BS=annualsupplementarygasenergyuseforasolarorheatpumpwaterheater(MJ/y) Be=annual electrical energy use by auxiliary equipment (MJ/y) 27AS/NZS 4234:2008 COPYRIGHT APPENDIX B STANDARD OPERATING CONDITIONS FOR DOMESTIC WATER HEATING IN NEW ZEALAND (Normative) B1 SCOPE ThisAppendixspecifiestheenvironmentalandloadconditionstobeusedforthe simulation for New Zealand. B2 TIME-LIMITED ELECTRIC SUPPLY The following electric boost availability times shall be used: (a)Continuous supply 24 h availability of electricity. (b)Night rate Hours of supply 10 pm to 7 am (a period of 9 h). (c)Extended Off-peak Hours of supply 10 pm to 5 pm (a period of 19 h). (d)Locally controlled Electric boosting set by controller supplied by manufacturer. B3 SOLAR COLLECTOR INCLINATION AND ORIENTATION ForNewZealandapplicationcollectorinstallationshallbefacingnorthwithclimatezone dependent inclination shown in Table B1. TABLE B1 COLLECTOR INCLINATION AND ORIENTATION ZoneCollector inclination, degrees to horizontal Collector azimuth,degrees from North 5400 6450 B4 CLIMATE DATA ThezonesshowninFigure B1arebasedonradiationdata.TypicalMeteorologicalYear (TMY)datarepresentativeofeachclimatezoneareshowninTable B2.TheNewZealand climatedataisavailablefromtheEnergyEfficiencyandConservationAuthorityofNew Zealand. TABLE B2 CLIMATE ZONES Zone TMY data source Latitude, degrees Longitude shift from standard time longitude, degrees Time datum Time at end of first record,h 5Auckland375.5New Zealand standard time 1.0 6Dunedin45.89.5New Zealand standard time 1.0 AS/NZS 4234:200828 COPYRIGHT FIGUREB2 CLIMATE ZONES FOR NEW ZEALAND B5 HOT WATER THERMAL ENERGY LOADS B5.1 Daily thermal load Peak daily thermal loads in winter are shown in Table B3. TABLE B3 NEW ZEALAND PEAK DAILY THERMAL ENERGY LOADS ZoneLarge system (6 occupants)MJ/d Medium system(4-5 occupants)MJ/d Small system (3 occupants) MJ/d 5523925.6 6523925.6 B5.2 Daily load profile ThedailyloadprofilesgiveninTables B4shallbeused.Eachloaddraw-offshallbe applied over a period of 0.1 h. 29AS/NZS 4234:2008 COPYRIGHT TABLE B4 DAILY LOAD PROFILE FOR NEW ZEALAND TimeDaily load multiplier Zones 5 and 6 06000.05 08000.16 10000.15 12000.11 14000.08 16000.07 18000.11 20000.13 22000.11 23000.03 B5.3 Seasonal load profile The seasonal energy load profiles shown in Table B5 shall be used. TABLE B5 SEASONAL LOAD PROFILE MonthSeasonal load multiplier Zones 5 and 6 January0.51 February0.58 March0.60 April0.72 May0.83 June0.89 July0.99 August1.00 September0.90 October0.83 November0.76 December0.65 B5.4 Hourly load The hourly load shall be calculated from the following equation: Hourly load = Peak daily load seasonal load multiplier daily load multiplier B6 COLD WATER INLET TEMPERATURE Cold-watertemperaturesforeachclimatezoneshowninTable B6shallbeusedasthe water inlet temperature to the storage tank. AS/NZS 4234:200830 COPYRIGHT TABLE B6 COLD WATER TEMPERATURE (C) MonthZone 5Zone 6 January2016 February2116 March1915 April1711 May159 June126 July115 August116 September138 October1511 November1713 December1915 B7 CHARACTERISTICS OF REFERENCE WATER HEATERS IN ZONES 5 AND 6 ThecharacteristicsofthereferencewaterheatersinNewZealandareshowninTables B7 and B8. TABLE B7 REFERENCE ELECTRIC WATER HEATER (CONTINUOUS BOOST) Tank size L Tank heat loss kWh/d Thermostat temperature C Thermostat differential K 1801.766510 TABLE B8 REFERENCE GAS WATER HEATERProduct class Tank size L Gas consumption MJ/h Thermal efficiency % Maintenance rate MJ/h Thermostat temperature C Thermostat differential K 3 star storage1702878.80.886510 B8 PURCHASEDENERGYFORREFERENCEWATERHEATERSIN ZONES 5 TO 6 TheannualenergyconsumptionofreferencewaterheatersinNewZealandsupplyingthe loads and load profiles defined in Tables B3, B4, B5 and B6 is given in Table B9. 31AS/NZS 4234:2008 COPYRIGHT TABLE B9 ANNUAL PURCHASED ENERGY CONSUMPTION OF REFERENCE WATER HEATERS IN NEW ZEALAND Peak winter daily load, MJ/dPurchased energy used MJ/y Water heater type Zone 5Zone 6Zone 5Zone 6 Electric large load525216 71016 900 Electric medium load393913 05013 240 Electric small load25.625.69 2809 460 Gas storage 3 star large load525225 73026 350 Gas storage 3 star medium load 393921 23021 870 Gas storage 3 star small load25.625.616 60017 240 NOTE: Gassystemenergyusedisprimaryenergyinput,whereaselectricsystemsgenerallyusesecondary energy. B9 DISPLACED ENERGYB9.1 Electric boosted products Thedisplacedenergyforasolarorheatpumpwaterheatershallbecomputedasshownin Equation B9.1. Displaced energy = [Br (BS+ Be)](MJ). . . B9.1where Br=annual electrical energy use of reference electric water heater (MJ/y) BS=annualsupplementaryelectricalenergyuseforasolarorheatpumpwater heater (MJ/y) Be=annual electrical energy use by auxiliary equipment (MJ/y) B9.2 Gas boosted products The displaced energy for a solar or heat pump water heater with gas supplementary heating shall be computed as shown in Equation B9.2. Displaced energy = [Br (BS + Be)](MJ). . . B9.2Where Br=annual gas energy use of reference gas storage water heater (MJ/y) BS=annualsupplementarygasenergyuseforasolarorheatpumpwaterheater(MJ/y) Be=annual electrical energy use by auxiliary equipment (MJ/y) AS/NZS 4234:200832 COPYRIGHT APPENDIX C WATER HEATER PARAMETERS (Normative) C1 GENERAL Thesystemparametersrequiredasinputstothesimulationdeckareoutlinedbelowfor thermosiphon, pumped solar water heaters and solar boosted heat pump water heaters. Some systems may require other parameters to be specified. NOTE: The units system used in TRNSYS is m, kg, h and kJ.All energy transfer rate parameters must be converted from W to kJ/h. C2 THERMOSIPHON SOLAR WATER HEATERS (Provide diagram showing relative position of tank and collector) Company Phone No. E-mail address Company officer reporting system characteristics Date Parameter Model number Tank ValueUnitsParameter name in example decks Tank model Tank inner diametermmdia Tank volume (physical not delivery) Lvoltot Tank configuration Vertical or horizontal Tkmode 1=vertical 2 = horizontal Tank wall thicknessmmt_wall Thermal conductivity of tank wall material W/m KK_wall Ratio of insulation thickness at top to bottom of horizontal tank IR 33AS/NZS 4234:2008 COPYRIGHT Ratio of insulation thickness at the top of the tank to the side of the tank for a vertical tank IR Volume of water above collector flow input to tank: volcol Tank heat loss (electric) Tank standing heat loss (AS/NZS 4692.1 conditions with element in the bottom of the tank) kWh/d for T = 55K Tnk_loss Test laboratory Date of test Test report number Tank heat loss (gas storage) Tank maintenance rate (AS 4552 conditions with gas booster in the bottom of the tank) MJ/h Temperature difference during maintenance rate testing K Test laboratory Date of test Test report number Supplementary boosting Electric boosting Volume of water above the electric element. For sickle elements the volume above the level with 50% of the active length of the element above and below. LVolaux Volume of water above the thermostat L Volhth Note: volhth