Thermal Applications Category User Guide

Transcription

1 Thermal Applicatins Categry User Guide Versin 6.3 Integrated Envirnmental Slutins

2 Cntents 1. What is the Thermal Applicatins Categry? <Virtual Envirnment> Cmpliance View Apache Applicatin View ApacheHVAC Applicatin View MacrFl Applicatin View Vista Applicatin View Data Requirements fr Thermal Applicatins Site Lcatin and Weather Data Cnstructins Prfiles Internal Gains Infiltratin and Ventilatin Plant and Cntrls Heating and Cling Znes <Virtual Envirnment> Cmpliance Checks Industry-standard Thermal Calculatins (ApacheCalc) Heat Lss Heat Gain Industry-standard Thermal Calculatins (ASHRAE Lads) Heating Lads Cling Lads Thermal Simulatin (ApacheSim) HVAC System Simulatin (ApacheHVAC) Natural Ventilatin Simulatin (MacrFl) Viewing and Exprting Simulatin Results (Vista)... 14

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4 1. What is the Thermal Applicatins Categry? The Thermal Applicatins Categry f the Virtual Envirnment is a set f sftware facilities fr the thermal analysis f buildings, the capabilities f which are utlined in this dcument. Guidance n the views and applicatins cntained within this Categry and their calculatin methds is set ut in separate manuals. Applicatins in the Thermal Applicatins categry fall int three main grupings: <Virtual Envirnment> cmpliance checks Analysis t test cmpliance with Part L f the UK Building Regulatins (2010) England & Wales Analysis t test cmpliance with Part L f the UK Building Regulatins (2002) England & Wales Analysis t test cmpliance with Sectin 6 f the Building Regulatins (2007) - Sctland Industry-standard thermal calculatins CIBSE heat lss calculatins (ApacheCalc, Vista) CIBSE heat gain calculatins (ApacheCalc, Vista) ASHRAE heating lads calculatins (ASHRAELads, Vista) ASHRAE cling lads calculatins (ASHRAELads, Vista) Dynamic simulatin (ApacheSim & related prgrams) Building dynamic thermal simulatin (ApacheSim) Natural ventilatin simulatin (MacrFl) HVAC system simulatin (ApacheHVAC) Results viewing and analysis (Vista, OutView, PltView) These applicatins are accessed via Applicatin Views as fllws <Virtual Envirnment> Cmpliance View Preparatin f input data fr England & Wales Building Regulatins cmpliance. Preparatin f input data fr Scttish Building Regulatins cmpliance Apache Applicatin View Preparatin f input data fr ApacheCalc ASHRAELads and ApacheSim. Calculatins and simulatins using ApacheCalc, ApacheSim, ApacheHVAC and MacrFl.

5 1.3. ApacheHVAC Applicatin View Preparatin f input data fr ApacheHVAC MacrFl Applicatin View Preparatin f input data fr MacrFl 1.5. Vista Applicatin View Presentatin and analysis f results frm ApacheSim, ApacheHVAC and MacrFl 2. Data Requirements fr Thermal Applicatins In cmmn with ther Virtual Envirnment applicatins, the Thermal applicatins derive their gemetrical data frm the MdelBuilder. This is supplemented with applicatinspecific data prvided within the Thermal Applicatin Categry. The input data requirements f the thermal applicatins are summarised belw. The data is managed by utility prgrams invked frm the Applicatin Views. Where pssible, applicatins access cmmn data s that it is never necessary t re-enter values in rder t carry ut different types f analysis. The efficiency f data input is further enhanced by the use f bjects called Templates. Templates bring tgether grups f thermal input variables s that they can be assigned cllectively t sets f rms, building elements r ther bjects. Cnstructin Templates stre descriptins f cnstructins fr the varius categries f building element (walls, flrs, windws and s n). Rm Thermal Templates stre sets f casual gains, air exchanges, plant peratin parameters and zning infrmatin assciated with rms f a given type. After a Rm Thermal Template is assigned t a rm it may be verridden by subsequent ad hc changes. Templates can be transferred between prjects. They ffer a pwerful means fr impsing structure n the input data, maintaining data quality and saving the user time. The fllwing is a summary f the data required by the thermal applicatins and the utility prgrams that manage this data Site Lcatin and Weather Data Data n the glbal lcatin f the building and the climate t which it is expsed are specified using the prgram APlcate. The lcatin data includes the latitude and lngitude f the site, tgether with infrmatin abut the lcal time zne and any summertime clck adjustment. The weather data cvers the requirements f bth the heat lss and heat gains calculatins and the thermal simulatin prgram. Fr the heat lss calculatin the weather data takes the frm f a single utside winter

6 design temperature. Fr the heat gains calculatin the data prvides hurly dry-bulb temperatures, wetbulb temperatures and slar data fr ne design day per mnth. Fr thermal simulatin the weather data is mre extensive and is stred n a simulatin weather file. This file cntains the values f the fllwing weather variables measured at hurly intervals ver a year: Dry-bulb temperature Wet-bulb temperature Direct beam slar radiatin Diffuse slar radiatin Wind speed Wind directin Clud cver Weather data in these frmats is available fr a large number f sites wrld-wide Cnstructins The material cmpsitin f the walls, windws and ther elements f the building fabric are described using the prgram APcdb (Apache cnstructins database manager). APcdb prvides databases f materials and cnstructins which may be imprted int the building and edited as necessary. Cnstructins are built up frm layers with specified thermphysical prperties and widths. In the case f glazing cnstructins the layer prperties include slar transmittance, absrptance and reflectance characteristics. Cnstructin details may be passed between prjects using a Cnstructin Template. The fllwing utilities are als prvided: Calculatin f U-values and admittance parameters Calculatin f glazing angular slar transmissin prperties Cndensatin analysis 2.3. Prfiles Prfiles prvide the means fr describing the time variatin f input variables. They are used t specify hw quantities such as casual gains, ventilatin rates and setpints vary ver the hurs f the day, the days f the week and the mnths f the year. Frmula prfiles allw inputs t vary in respnse t rm r external cnditins arising during simulatins. Prfiles are managed by the prgram APpr Internal Gains Infrmatin n heat gains frm ccupants, lights and equipment is required as input t

7 heat gain calculatins and thermal simulatin. Heat gains may be sensible r latent, and sensible gains are characterised by a radiant fractin. The magnitude and types f these casual gains, tgether with prfiles t indicate their time variatin, may be specified individually fr each rm r incrprated within a Rm Thermal Template Infiltratin and Ventilatin Infiltratin and ventilatin rates fr rms are specified by assigning them a maximum value and a prfile. Ventilatin rates can represent either mechanical r natural ventilatin. The surce f the ventilatin may be utside air, air frm anther rm r air at a specified (pssibly time-varying) temperature. Like casual gains, air exchanges may be incrprated within a Rm Thermal Template. These pre-specified air exchanges may be supplemented by natural and mechanical ventilatin air flws calculated dynamically at simulatin time by the prgrams MacrFl and ApacheHVAC Plant and Cntrls Where rms are cnditined by heating, cling, humidificatin r dehumidificatin systems the characteristics f these systems must be specified. The specificatins fr rm cntrl include set-pints, heating and cling capacities and radiant fractins, tgether with prfiles defining perids f plant peratin. These parameters frm part f the Rm Thermal Template data. In the case f thermal simulatin, these idealised rm cntrl parameters may be verridden by detailed HVAC system mdels cnstructed in ApacheHVAC Heating and Cling Znes In the Thermal view, rms may be gruped tgether int Heating Znes and Cling Znes fr the purpse f aggregating results frm a calculatin r simulatin. 3. <Virtual Envirnment> Cmpliance Checks The <Virtual Envirnment> cmpliance prgrams assess regulatry cmpliance fr fur building regulatin methdlgies: Analysis t test cmpliance with Part L1 (SAP 9.80) f the UK Building Regulatins (2006) England & Wales Analysis t test cmpliance with Part L1 (UK Dwellings) Analysis t test cmpliance with Part L2 (Nn-dmestic buildings) f the UK Building Regulatins (2010) England & Wales Analysis t test cmpliance with Sectin 6 f the Building Regulatins (2010) Sctland

8 Infrmatin required fr these cmpliance checks is explained in the fllwing dcuments that can all be fund in the manuals directry f the IES <Virtual Envirnment> installatin: <Virtual Envirnment> Cmpliance View User Guide Part L1 (2002) Methds Part L2 (2002) Methds 4. Industry-standard Thermal Calculatins (ApacheCalc) The prgram CIBSE Heat Lss & Heat Gain (ApacheCalc) perfrms heat lss and heat gain calculatins accrding t the prcedures laid dwn in CIBSE Guide A (1995, 1999, 2001) Heat Lss Heat Lss prvides fr the calculatin f rm heating requirements and the sizing f heating plant. Steady-state rm heat lsses are calculated in the absence f casual and slar heat gains. The calculatin ptinally includes cnductin heat gains frm adjacent rms and the effects f mechanical and natural ventilatin air exchanges. Results are presented (in the prgram Vista) as tables r histgrams f rm r zne heat lss, brken dwn by heat lss mechanism. Lsses can be expressed n a flr area r rm vlume basis. Rm temperatures are als displayed. The data may be exprted t ther applicatins such as spreadsheets and wrd prcessrs. Pst-prcessing ptins include the fllwing: 4.2. Heat Gain Inclusin f a factr fr intermittent plant peratin Radiatr selectin Heat Gain calculates rm cling requirements and summertime temperatures. Rm cling lads and free-flating temperatures are calculated using the CIBSE admittance prcedure. The calculatin is carried ut fr a user-selected range f mnths using weather data prvided in APlcate. The calculatin takes int accunt the timing and nature f each gain, applying the apprpriate radiant fractin t all surces f heat and cling. Inter-rm dynamic cnductin and ventilatin heat transfer is accunted fr. Glazing slar transmissin prperties are treated using an analysis based n the Fresnel equatins. At the user s ptin the effects f ventilatin air exchanges and external slar shading, as calculated by SunCast, may be incrprated.

9 The prgram Vista presents the results in tabular r graphical frm in a variety f frmats. Gains are brken dwn by heat transfer mechanism and by type (sensible r latent). Results may be displayed by rm, by zne r ttalled ver the building and peak lads are identified. Varius measures f rm temperature are displayed, tgether with rm relative humidity. Data may be exprted t ther applicatins. Pst-prcessing facilities are prvided as fllws: Calculatin f ventilatin supply cnditins that will meet the calculated cling lads User-definable tables f lads 5. Industry-standard Thermal Calculatins (ASHRAE Lads) The prgram ASHRAE Heating and Cling Lads (ASHRAELads) perfrms heating and cling lad calculatins accrding using the ASHRAE Heat Balance Methd 5.1. Heating Lads Heating Lads prvides fr the calculatin f rm heating requirements and the sizing f heating plant. Steady-state rm heat lsses are calculated in the absence f casual and slar heat gains. The calculatin ptinally includes cnductin heat gains frm adjacent rms and the effects f mechanical and natural ventilatin air exchanges. Results are presented (in the prgram Vista) as tables r histgrams f rm r zne heat lss, brken dwn by heat lss mechanism. Lsses can be expressed n a flr area r rm vlume basis. Rm temperatures are als displayed. The data may be exprted t ther applicatins such as spreadsheets and wrd prcessrs. Pst-prcessing ptins include the fllwing: Inclusin f a factr fr intermittent plant peratin Radiatr selectin 5.2. Cling Lads Cling Lads calculates rm cling requirements and summertime temperatures. Rm cling lads and free-flating temperatures are calculated using the ASHRAE Heat Balance Methd. The calculatin is carried ut fr a user-selected range f mnths using weather data prvided in APlcate. The calculatin takes int accunt the timing and nature f each gain, applying the apprpriate radiant fractin t all surces f heat and cling. Inter-rm dynamic cnductin and ventilatin heat transfer is accunted fr. Glazing slar transmissin prperties are treated using an analysis based n the Fresnel equatins. At the user s ptin the effects f ventilatin air exchanges and external slar shading, as calculated by SunCast, may be incrprated. The prgram Vista presents the results in tabular r graphical frm in a variety f

10 frmats. Gains are brken dwn by heat transfer mechanism and by type (sensible r latent). Results may be displayed by rm, by zne r ttalled ver the building and peak lads are identified. Varius measures f rm temperature are displayed, tgether with rm relative humidity. Data may be exprted t ther applicatins. Pst-prcessing facilities are prvided as fllws: Calculatin f ventilatin supply cnditins that will meet the calculated cling lads User-definable tables f lads 6. Thermal Simulatin (ApacheSim) ApacheSim is a dynamic thermal simulatin prgram based n first-principles mathematical mdelling f the heat transfer prcesses ccurring in and arund a building. ApacheSim qualifies as a Dynamic Mdel in the CIBSE system f mdel classificatin, and exceeds the requirements f such a mdel in many areas. The prgram prvides an envirnment fr the detailed evaluatin f building and system designs, allwing them t be ptimised with regard t cmfrt criteria and energy use. Within ApacheSim, cnductin, cnvectin and radiatin heat transfer prcesses fr each element f the building fabric are individually mdelled and integrated with mdels f rm heat gains, air exchanges and plant. The simulatin is driven by real weather data and may cver any perid frm a day t a year. The time-evlutin f the building s thermal cnditins is traced at intervals as small as ne minute. Results utput by the simulatin include: Cmfrt statistics Energy cnsumptin data CO 2 emissin data Rm lad statistics Plant sizes Detailed perfrmance measures including hurly rm temperatures (air, mean radiant and dry resultant), humidities, plant lads, casual gains and air exchanges Surface temperatures fr cmfrt studies r CFD bundary cnditins The simulatin engine has the fllwing features: Finite difference dynamic heat cnductin mdelling Dynamically calculated surface cnvectin characteristics Air temperature, surface temperature and rm humidity mdelling Advanced slar and lng-wave radiatin exchange mdels External slar shading using data frm SunCast

11 Slar tracking thrugh an arbitrary number f transparent internal partitins using data frm SunCast Angle-dependent glazing transmissin, reflectin and absrptin characteristics Accurate accunting fr the radiant/cnvective characteristics f casual gains and plant heat inputs Rm plant and cntrl mdels allwing fr limited heating r cling capacity Simultaneus slutin f sensible and latent heat balance equatins fr the whle building Optinal integratin with natural ventilatin air flw simulatin (MacrFl) r HVAC system simulatin (ApacheHVAC) Simultaneus integratin with bth MacrFl and ApacheHVAC fr the simulatin f mixed-mde systems 7. HVAC System Simulatin (ApacheHVAC) ApacheHVAC simulates the perfrmance f heating, ventilatin and air cnditining systems. It links dynamically t the building simulatin prgram ApacheSim, and ptinally t MacrFl. ApacheHVAC extends the capabilities f ApacheSim by prviding a detailed representatin f rm heating and cling units, air handling systems, central plant cmpnents and cntrls. These capabilities give the user a means f accurately assessing issues such as: Cntrl peratin and its impact n cmfrt perfrmance Energy use Fresh air lads Free cling Heat recvery Cmpnent sizing Sizing f mechanical air flws System psychrmetrics Distributin efficiency Biler and chiller perfrmance Fan and pump energy Mixed-mde peratin Wrking thrugh a graphical interface the user assembles a system schematic n screen and sets peratinal parameters fr its cmpnents. Editing features facilitate peratins such as cpying and mving grups f cmpnents. The list f available cmpnent building blcks includes:

12 Rms Radiatrs Direct-acting heaters and clers Chilled ceilings Heating and cling cils Ducts Fans Humidifiers Heat recvery devices Cntrllers Bilers Chillers Cntrllers may be cnfigured fr bth n-ff and prprtinal cntrl, and may be cascaded t simulate cmplex cntrl functins. Time variatin f peratinal parameters is handled with prfiles, and frmula prfiles ffer additinal flexibility in cntrl specificatins. The cmpnent-based nature f the interface makes pssible an almst unlimited range f system types, f which the fllwing are examples: Variable air vlume (VAV) Cnstant air vlume (CAV) Fan-cil Displacement ventilatin Chilled beams Radiatrs Underflr heating If the MacrFl check bx is ticked at run-time the simulatin will include natural ventilatin analysis. MacrFl will then incrprate in its calculatins any flw imbalances arising in the system simulatin, prviding a rute fr the simulatin f mixed-mde systems. ApacheHVAC generates an extensive range f utputs. At the detailed level it is pssible t trace individual psychrmetric and cntrl prcesses ccurring within a system. At the ppsite extreme the prgram can supply aggregated mnthly energy lads and cnsumptin ttals, ptinally brken dwn by fuel r cmpnent type.

13 8. Natural Ventilatin Simulatin (MacrFl) MacrFl is a simulatin prgram fr the design and appraisal f naturally ventilated and mixed-mde buildings. MacrFl runs as an adjunct t ApacheSim, exchanging data at run-time t achieve a fully integrated simulatin f air and thermal exchanges. The fllwing issues may be addressed with MacrFl: Infiltratin Single-sided ventilatin Crss-ventilatin Natural ventilatin as a whle-building strategy Temperature-cntrlled windw pening Mixed-mde slutins (used in cnjunctin with ApacheHVAC) MacrFl simulates the flw f air thrugh penings in the building envelpe. Openings are assciated with windws, drs and hles created in the gemetry mdel and may take the frm f cracks r larger apertures. Air flw is driven by pressures arising frm wind and buyancy frces (stack effect). It als takes accunt f mechanical air flws set up in ApacheHVAC. Wind pressures n the building exterir are calculated at each simulatin time step frm data read frm the weather file. Wind speed and directin data is cmbined with infrmatin n pening rientatins and wind expsures t generate wind pressures n each external pening. The calculatin invlves wind pressure cefficients derived frm wind tunnel experiments. Buyancy pressures, varying with height in accrdance with temperature-dependent air densities, are then superimpsed. The flw thrugh each pening is calculated as a functin f the impsed pressure difference and the characteristics f the pening. The height dependence f the buyancy pressures means that tw-way flw can ccur thrugh a single pening either side f a neutral pressure plane. Special situatins such as the Rayleigh instability are detected and mdelled apprpriately. A netwrk f pressure-flw relatinships is slved t balance the flws in and ut f each rm. MacrFl exchanges data with ApacheSim and ApacheHVAC dynamically t achieve the simultaneus slutin f the inter-dependent thermal and air flw balances. Input data fr MacrFl is prepared in the MacrFl applicatin. Wrking frm an editable database f Opening Types the user assigns pening prperties t windws and drs in the mdel. This prcess fllws the same pattern as the assignment f cnstructin types fr the thermal analysis. Opening Type prperties allw fr the specificatin f crack characteristics, the degree and timing f windw pening and (as apprpriate) its dependence n rm temperature. Opening Types may be stred in a Template.

14 9. Viewing and Exprting Simulatin Results (Vista) The Vista prgram prvides facilities fr the display, cllatin and exprt f data generated by the Virtual Envirnment s thermal simulatin applicatins. Vista is itself a cmpnent f the Virtual Envirnment and as such has access t the gemetry mdel stred in the MdelBuilder view. The gemetry mdel prvides a natural framewrk fr brwsing simulatin utput datasets. By pinting t rms n the mdel image yu can instantly call up graphs r tables f rm temperatures, plant lads, casual gains and ther simulatin variables. Results fr different rms can be displayed n the same axes r juxtapsed, and similar cmparisns can be made between results datasets derived frm alternative design ptins. Results frm MacrFl may be displayed at either the rm level r the pening level. T btain a detailed picture f natural ventilatin flws the user can pint t an pening t view graphs f in-flws, ut-flws and the degree f pening. Energy and lad ttals frm ApacheHVAC can be displayed as hurly time series r mnthly ttals.