Presentation on theme: "DESIGN AND CALCULATION TOOLS"— Presentation transcript:
1 DESIGN AND CALCULATION TOOLS ENERGY EFFICIENCY ANDSUSTAINABILITY OF BUILDINGSDESIGN AND CALCULATION TOOLSProf. dr. Marija TodorovicDERES - DIVISION FOR ENERGY EFFICIENCY ANDRENEWABLE ENERGY SOURCESFaculty of Agriculture, University of Belgrade, Serbiath November
2 AIM OF THIS LECTUREIntroduction of the UNESCO E-Learning audience to the computational modeling techniques which are, as the most powerful current design and calculation tools, increasingly being used to successfully predict the internal and external conditions within and around buildings, as well as the buildings energy loads and consumption.Building services engineers, architects, developers and clients use the results to evaluate HVAC strategies to ensure specific project requirements are achieved on-site first time. Substantial savings can be made through low cost design and the avoidance of on-site re-design and re-commissioning.
3 DEFINITIONS - DYNAMIC THERMAL SIMULATION AND CFDA computer model of the energy processes within a building that are integrated to provide a thermally comfortable environment for the occupants (or contents) of a building - Building Performance Simulation (BPS) and BPS & prediction (BPSP).The external environment of a building changes permanently. Due to its thermal capacity, the structure and fabric of, a building responds to these changes. This in turn leads to a more gradual dynamic response of the interior climate and to HVAC’s, lighting’s and other technical systems loads and energy use variation.Prediction of dynamics of these changes is of crucial importance in the design of building’s energy efficient heating, cooling & air-conditioning strategies.
4 DYNAMIC THERMAL SIMULATION AND CFD -COMPUTATIONAL FLUID DYNAMICS Dynamic Thermal simulation can predict changing internal conditions over a time period of up to 1 year – TMY 8760 hours.The technique predicts zonal (or room) values for parameters such as air temperature.With ever improving computer technology, the use of CFD in Building Design and in the design of HVAC strategies is becoming more widespread.CFD is the only choice to obtain the important details of the internal climate which result from a particular HVAC design.The expertise necessary to fully utilise the latest CFD software for design issues, be they internal environment relevant (velocity, humidity, concentration field and air flows) or external (wind-driven) air flows.
5 BUILDINGS PERFORMANCE SIMULATION Describe the building- Physically- Mathematically- Focus on HVAC, lighting and energy supplyComputer programs- Whole building programs- Component-based, modular simulatorsInterpret and use the results
6 PURPOSE OF BUILDINGS PERFORMANCE SIMULATION Buildings use % of national energyImprove/optimize energy efficiencyEfficiently introduce RESReduce LCC - life cycle costsImprove comfort and habitabilityDevelop codes and standardsAddress special design problemsHistorical building renovationInnovative designLocal requirements, i.e., no A/C
7 WHO SHOULD PERFORM BP SIMULATIONS A & E firmsdesign/optimize EE issues, marketingLarge property ownersoperational policy/energy cost, retrofitGovernment agenciescode development & enforcementResearch labsimproving knowledge base, extending state- of-the-artUtility companiesmarketing, planning
8 WHOLE BUILDING SIMULATORS Model 5 to 50 and more thermal zonesDetailed description of constructionDetailed representation of load profiles of components and totalAnalyze HVAC systems and plant optionsSomewhat simplified/or optimized numerically – improved convergencePreviously: DOE-2, BLAST, AXCESS, TraceNow: EnergyPlus, PowerDOE, DesignBuilderESP-r, APACHE, lots of third party derived products
9 EFFECTIVENESS AND EFFICIENCY OF MODULAR SIMULATORS Difficulties in describing complex envelopes and structuresComplete flexibility/interoperabilityRigorous numerical methodsShorter solution timesCould be better suited to whole integrated building/HVAC simulationsTRNSYS, HVACSIM+, SPARK, IDA
10 CURRENT ISSUES- WHOLE INTEGRATED BUILDING DESIGN Flexibility- HVAC System & Plant- Building shell description- Usage patternsEase of use wider usageAccuracy- Integration: all-in-a-time step calcs.- Hi-tech: CFD, boundary conditions,contaminant tracking- ValidationCost effectiveness
11 FUTURE R&D TYPES FOR DIFFERENT USERS GROUPS Four principal future R&D types for different users can be distinguished, each of which have their own particular needs:building and its technical and HVAC systems designers and operators,building investors and users,local or regional government policy makers andbuilding/HVAC systems physics phenomena and construction HVAC engineering researchers.
12 INTEGRATED BUILDING DESIGN Need for wider implementation and DisseminationNew technological approachin designingSUSTAINABLE “GREEN” BUILDINGSconsidering energy efficiency,renewable energy and renewable raw materials utilization and environmental technologies implementation.
13 CFD – PHOENICS, CFX, FLUENT Multimodel approach in Integrated Building Design – Energy Efficiency OptimisationTRNSYSDOE2 SERIESVISUAL DOEENERGY PLUS, ESP-rAPACHEGen OptADELINE – RADIANCESPARK, IDA ICECFD – PHOENICS, CFX, FLUENT
14 GenOpt A GENERIC MULTI-PARAMETER PROGRAM FOR SYSTEM OPTIMIZATION. Automatically determines the values of user-selected design parameters that lead to the best operation of a given system.Optimizes a user-selected objective function, such as a building's calculated annual energy use.Offers an interface for implementing own optimization algorithms into its library, and has an open interface on both the simulation program side and the optimization algorithm side.By modifying a configuration file, it allows users to easily couple any external program (like DOE-2, SPARK, BLAST, EnergyPlus, TRACE, TRNSYS, etc., or any user-written program).GenOpt is written entirely in Java so that it is platform independent. An interface for coupling external simulation programs and adding custom optimization algorithms is available.
15 Domain specific Common Framework Envelope & ZoneHeat BalanceModels & SolutionClimate &RadiationModels & SolutionHVACModels & SolutionMultizone AirModels & SolutionDomain specificTypical architecture of a simulator in the traditional approach
16 GUI Equation Based Framework Domain independent Domain specific Envelope & ZoneHeat BalanceModelsClimate &Radiation ModelsShadingModelsNumericalSolver 1NumericalSolver 2SymbolicProcessorLanguageParserHVACModelsDomain independentDomain specificBasic architecture of an equation based building simulator
17 MODELED TO SOME EXTENT TO FORM A MEANINGFUL SIMULATION MODEL AREOutdoor climate conditions, includingtemperature and incident solar radiationDynamic heat flux through the buildingenvelope and internal structureHeat balance of each room (or ventilated zone)Air, water flows andHeat flow through the primary andSecondary HVAC system
18 Windows and daylighting Thermal BridgesWindow simuation studyTherm Series
19 MANY TOOLS ALSO MODEL A SERIES OF THE CLOSELY COUPLED QUANTITIES Moisture transport within the buildingCost of supplied energyThermal sensation (comfort) of buildingoccupantsDaylightingNaturally occurring air-flows between andwithin zonesIndoor Air QualityPerformance of ground-coupled systems
20 Three typical purposes and corresponding time-scales of building performance simulations Prediction of extreme conditions (design day or design period of year) Prediction of the energy consumption (per year) Prediction of controller action (1/100- seconds) Typical Meteorological Year
21 Buildings Energy Tools Software by Subject Whole Building AnalysisEnergy SimulationLoad CalculationRenewable EnergyRetrofit AnalysisSustainability/Green BuildingsCodes & StandardsMaterials, Components, Equipment, & SystemsEnvelope SystemsHVAC Equipment and SystemsLighting SystemsOther ApplicationsAtmospheric PollutionEnergy EconomicsIndoor Air QualitySolar/Climate AnalysisTrainingUtility EvaluationValidation ToolsVentilation/AirflowWater ConservationMisc. Applications
22 AAMASKY skylights, daylighting, commercial buildings Total number 335 ABACODE Residential code compliance, IECCACOUSALE acoustics, codes and standardsAcoustic Program HVAC acoustics, sound level prediction, noise levelADELINE daylighting, lighting, commercial buildings buildingsAFT Fathom design, pump selection, pipe analysis, duct design, duct sizing, chilled water systems, hot water systemAFT Mercury optimization, pipe optimization, pump selection, duct design, duct sizing, chilled water systems, hot water systemsAGI32 lighting, daylighting, rendering, roadwayAIRPAK airflow modeling, contaminant transport, room air distribution, temperature and humidity distribution, thermal comfort, computational fluid dynamics (CFD)AkWarm home energy rating systems, home energy, residential modeling, weatherizationAnalysis Platform heating, cooling, and SWH equipment, commercial buildingsAnimate animated visualization of data, XY graphs, energy-use dataAnTherm thermal bridges, heat flow, steady state, transfer coefficients, temperature distributionApache thermal design, thernal analysis, energy simulation, dynamic simulation, system simulation
24 MODELS IN BUILDING ENERGY PERFORMANCE SIMULATION CLASSIFICATION Dynamic- Uniform time unitDiscrete- Continous change captured at “discrete moments”Deterministic- Decisions based on certaintyModels for (comparative) analysis
25 KNOW AND UNDERSTAND ASSUMPTIONS Explicitly stated/documented assumptionsImplicit assumptionsAssumptions based on (scientific) factAssumptions based on conventionaal wisdomAssumptions based on educated guessesAssumptions based on wild guesses
26 GOALS OF BUILDING THERMAL SIMULATION Load Calculations- Generally used for determining sizing of equipment such as fans, chillers, biolers, etc.Energy Performance Analysis- Helps evaluate the energy cost of the building over longer periods of time
27 SIMULATIONS DO ENERGY SAVING Building thermal simulation allows one to model a building before it is built or before renovations are startedSimulation allows various energy alternatives to be investigated and options compared to one anotherSimulation can lead to an energy-optimized building or to a more informated design processSimulation is much less expensive and less time consuming than experimentation – every building is unique
28 EVERY BUILDING IS UNIQUE Every building is different in many ways:- Location and exterior thermal environment- Construction/building envelope- Space usage/interior environment- HVAC systemExterior thermal environment is a driving force that determines how a building will respondEnergy efficient design requires an understanding of and a response to the exterior thermal environmentThermal simulation requires information on the exterior thermal environment to properly analyze the building from an energy perspective
29 ADDITIONAL FORECASTSBuilding performance analysis and evaluation through computer modeling and simulation will likely become increasingly important- Encourages product innovation- Fits the entrepreneurial market- Allows design flexibility- Provides for cost optimizationThere will be increasing market pressure to verify, certify and accredit building energy performance software tools.
30 MORE CONTEXTAs little as 10 years ago, detailed building energy simulation and analysis was effectively limited to “research institutes”Significant computational power (memory and speed) neededSignificant user knowledge (thermodynamics, materials, algorithms, etc.) neededToday’s powerful PCs, databases and GUIs have changed our worldNow “dumb” users plus “smart” interfaces can achieve acceptable results.
31 Performance-based codes and standards “Beyond code” programs SOME OF THE INCENTIVESPerformance-based codes and standards“Beyond code” programsDOE Building America programEPA ENERGY STAR® program“Green building” programs (LEED, etc.)Utility & “public benefits fund” incentivesProposed federal tax incentivesPollution and “Carbon” programsEPA non-attainment program (Texas)European Union’s “Energy Performance of Buildings Directive” (EPBD) – mandatory!
32 EU EPBD PROGRAMMandatory across EU for all buildings (existing and new) starting in January 2006!Requires each country to introduce a standard energy calculation methodologyFor all but simple buildings, requirement is being interpreted as a detailed simulation toolQuestions about software standards, testing and verification.
33 NEW CHALLENGING GOALSGoal is dramatic improvement in residential purchased energy use40% - 70% more efficiency byUltimate goal: Zero-Energy Homes70% efficiency improvement plus on-site PV power production for remainder (net zero)Design, analysis, accounting and reporting based on detailed simulation analysis.
34 PERFORMANCE STANDARDS ChallengesBasic principles are poorly understood by many (most building officials)Confusing lingo: Standard design, Reference home, Baseline home, Benchmark homeMistrust by building officials (“black box”)Consensus-based decision makingMyth is more widespread than you thinkScience is often difficult to explainThere are often unintended consequences (scientists do this a lot)!
36 Algorithm Differences Reference results can vary widely!
37 COMPONENTS SPECIFIED Above grade walls Basements and crawlspace walls Above grade floorsCeilingsRoofsAtticsFoundationsDoorsGlazingSkylightsSunroomsAir exchange ratesMechanical ventilationInternal gainsInternal massStructural massHeating systemsCooling systemsService hot waterThermal distribution systems
38 OTHER IECC* REQUIREMENTS Computer generation of standard reference design – no user modification allowedCalculation of equipment sizing for standard reference designGeneration of official inspection checklist listing each of the proposed design component characteristicsCalculations that account for effects of climate and equipment sizing on system performance.*International Energy Conservation Code
39 IBPSA CHALLENGESParticipate actively in efforts to develop software verification methods and test suitsSeek methods to reduce real differences in software results due to algorithm differencesHelp all of us walk that fine line between the most advanced simulation models and techniques the CEFAPP needs of the marketplace.
40 BUILDING’S EXPERIMENTING Repeatable physical experiments on buildings are often difficult to perform.Many building systems are too bulky for laboratory measurements and long term measurement on real buildings are either expensive, due to the cost of an unoccupied building, or disturbed by building utilization.This makes computer based experimentation onbuilding models attractive.
42 INNOVATIONS IN CONSTRUCTION INDUSTRY The building industry is oriented towards one-of-a-kind production, with a low relative investment in engineering.Coupled with the difficulty of in situ measurements, this creates unfavorable conditions for innovation and performance feedback.The process of natural refinement of engineering solutions is therefore slow.Ability to experiment with new solutions in the design office by simulation is bound to improve this situation, if the right tools are available.
43 EXPERIMENTING BY SIMULATIONS Furthermore, since malfunctions in the delivered product are difficult to detect andquantify, designs that do not perform correctly, even theoretically, are sometimes realized.If design offices were obliged to demonstrate intended functionality on a computer model prior to realization, many such problems could be avoided.
44 SUCCESSFUL DEVELOPMENT HISTORY Whole-Building Simulators Under Floor Air Distribution System (versions 1.01, 1.1)Have the supply plenum, slab coupling, need better zone modelGround Coupling (version 1.01)Photovoltaics, TRNSYS link (versions 1.01, 1.1)Cooled beams, cooled ceiling panels (version 1.1)Equipment sizing (versions 1.01, 1.1)Heat recovery: more types, controls (versions 1.01, 1.1)Missing old stuffair-to-air, water loop, ground source heat pumps (version 1.01)
45 Energy Plus SIMULATION FLEXIBILITY VS. SIMPLICITYHVAC Simulation Based on Configurable Input Template SystemsCode Allows Connection FlexibilityInput Defines Specific System Configurations - Connections are in the InputCompletely Modular Systems and Real-Time Controls Handled by Links to SPARK and TRNSYS
46 30+YEARS OF BUILDING SIMULATION User interface advanced from:Numbers (NBSLD) toTextual languages (DOE-2, BLAST) toGUIs (PowerDOE, DOE-2 add-ons)Perhaps we are nearing “user friendly” and ready for the practitioner?
47 30+YEARS OF BUILDING SIMULATION Modeling paradigm shifted from:Procedural languages (NBSLD*) toMonolithic programs (DOE-2, BLAST) toModular simulators (TRNSYS, HVACSIM+) toObject oriented simulators (SPARK, IDA)Still need to merge this technology with the whole building programs.*National Bureau of Standards Load Determination
48 30+YEARS OF BUILDING SIMULATION Solving method shifted from:Hour-by-hour solving without iteration (DOE-2, BLAST) toSub-hourly time step with iteration (EnergyPlus) toProper error controlled numerical solving of differential algebraic systems (SPARK, IDA)Still need to integrated all this into the whole building codes.
49 NEW ADDITIONS in Energy Plus Fully Integrated Loads & HVAC SimulationExample: chiller capacity exceededOccupant ComfortMoisture storage and releaseMix and Match systemsGreen BuildingsExample: natural ventilation, COMISLots moreLow and high temperature radiant heatingsupply air plenums
50 Mathematical modeling Application development Model use measurement specificationMathematicalmodelingFormallyDescribedmodelsLibrary modelsresearchersApplicationdevelopmentReady madeapplicationsSoftwareengineersspecificationModeluseSimulationresults. Mathematics. Physics. Signal processing. Experimentationconsultants. Software development. Customer support. Market awareness. Other primary competence
51 CREATING SUSTAINABLE, ENERGY EFFICIENT BUILDINGS FOR THE FUTURE An energy concept is a complete combined solution to energy efficiency in buildings and energy supply incl.– Demands on building design andinstallations– Energy storage and local energyproductionThe aim is to find the optimal solutions
52 WHAT IS NECESSARY TO OPTIMIZE AN ENERGY EFFICIENCY? Considerable efforts from project startGood co-operation between architects and engineers and adedicated clientSpecialist knowledge, inventiveness, and information on new solutionsFollow-up on the preconditions of the buildingAnalysis of a number of innovative solutionsSelection of a solution with good indoor climate and asenvironmental friendlyOptimisation with the reference to the cost effectivenessand overall economy
53 WHAT IS THE PRICE? NO extra investment costs are needed! In case of an optimal combination, theconstruction costs will be cheaperAdd to this operational savings for energyand maintenance!
54 INEXTRICABLE LINKAGERES, REM, EnEfficiency and Sustainable DevelopmentAll level regular and vacational Education, Engineering Experience (Designing, Construction, LCCommisioning and Operation)Most current knowledge and technologies and Mental awarness/Ethics of SustainabilityCost effectiveness/harmonization of- Dynamics of final energy user’s loads- Dynamics of Co/Trigeneration efficiency- Dynamics of technically available RES fluxesSmall specific energy fluxes and Distributed character of RES versus Distributed Co/Trigeneration