Advances in building energy simulation tools and integration of microclimate issues

Transcription

1 Advances in building energy simulation tools and integration of microclimate issues Les outils de simulation thermique en développement au sein de la recherche française et européenne Maxime DOYA, Emmanuel BOZONNET, Francis ALLARD, Adrien GROS 1

2 Building Energy Simulation (BES) tools Integration of surrounding urban environment Applications for Urban Heat Island (UHI) mitigation 2

3 Building environmentsystem: a conceptual model "Modeling is to replace visible simple thing with complex invisible thing" (J. Perrin) Lighting Information & Communication HVAC Occupants Fire & Safety Surrounding Environment Building Envelope Power & Energy Water Supply & Drainage : Flows of energy, mass, and information 3

4 Multi-disciplinary approach 4

5 Simulation tools for Integrated Design "It has been found that a host of factors, once not even considered, must be taken into account in the designing of buildings. And, with the advanced technology, knowledge, and living standards, their number is continually being augmented." B. A. Handler Systems approach to architecture 5

6 Tools adapted to different aims (.) Building Regulation BUILDING ENERGY SIMULATION (BES) - For real performance assessment -Necessary for High performance systems and buildings - Mandatory - For standardized and simplified situations - Not realistic especially for summer Labels and diagnostics - Validation of different levels - Simulation or regulation codes E. Bozonnet(2013) 6

7 Levels of expertise in existing softwares 7

8 Coupling numerical codes Energy : Thermal behavior zone temperatures Estimate of HVAC powers (heating and cooling systems) Airflows from infiltration or ventilation driven through rooms can be integrated as input parameters (not as variables) Airflow: describe the air movement Driven by a main variable : Pressure Accurate data are necessary to run precise simulations : Wall air permeability, ventilation systems, openings geometry and air temperature of each zone Coupled energy and airflow : union of the first two categories 8

9 Levels of accuracy Detailed Choice of a level of accuracy adapted to the case study Global CFD Zonal Multizone Monozone -R&D oriented -Fine decomposition of a particular element -Large computation time -R&D oriented -each room is decomposed in subvolumes -wall partition in connection with the air volume s one -the most used for BES -1 zone per occupancy type/ particular thermal/flow regime -description of envelope and zone interfaces -The most simplified (regulation or label) -1 well-mixed zone describing the whole building -description of envelope Unique room Temperature, Thermal comfort, powers Building 9

10 Occupant Multi-Scales: both spatial and temporal Spatial: 0-1 m 1-10 m m Micro O.A. Meso O.A ,000 m km Temporal: Seconds Minutes Hours Personal Days ventilation Smart furniture Micro- air conditioner Micro- Zone/ Multizone Outdoor Indoor Material Env. Room Building Airshed Selection Room conditioning Ventilation Multi-level Controls / Interface: Occupant Satisfaction: Goals: F. Allard & J. Zhang (2013) Envelope definition Material selection HVAC system ~100% >90% >80% (ISO, CEN, ASHRAE, National Standards,) IEQ Energy Safety & Security Urban planning Source control Energy sharing Solar potential 10

11 BES Modeling& Simulations a multi-scale problem Climate Environmental systems Internal zoning External enclosure Site & landscape Form, massing & orientation 11

12 Evolution of Building Energy Models 1960 s 1970 s 1980 s 1990 s 2000 s Energy loads Energy demand Energy supply & demand Energy sources Bldg & urban envir. Largely steady state heat flux model for envelope 1 st application of response factor method (Mitalaset al. 1960) Transient heat flux model for envelope Wide application of transfer function method (DOE1, DOE2, ESP-r) Air jets for room model ADPI 1 st CFD application (Nielsen 1974) Integrated consideration in heating/cooling supply & demand Whole building envelope and HVAC system model (Transys, ESP-r, DOE2, BLAST) 1 st try to couple multizoneairflow network model (COMIS, CONTAM, BREEZ, ) Zonal model CFD development Demand side management for peak load reduction Renewable energy source modeling (solar, wind & ground source heat pumps) Enhanced energy simulation capabilities (EnergyPlus, ESP-r) Wide application of CFD model Corse grid CFD, FFD and zonal models Coupling between BES and urban micro-env. Models Coupling with IAQ Models Coupling between different platforms (LNBL-BCVTB) CHAMPS Design-oriented model (Ecotech) Start of integration with BIM Reduced-order model development Séminaire AVITEM 16/10/

13 Challenge : Coupling with environmental models In most cases, it is no more possible to consider that buildings are isolated and do not interact with their environment.(use of renewable energy, ventilation cooling, pollutant transport, Heat Island reduction strategies, ) Distribution of cooling load [kwh/m 3 ] in Athens 2004, for a set point of 26 C, (Santamouris et al,2004) 13

14 Meteo Model Region City Microclimate model Forest Canopee Street Urban Canopee Geostrophic Wind Troposphère Building Meteo Station Canyon street Calculated velocity Vitesse d'air [m/s] simulation mesure E. Bozonnet(2005) temps [h] Numerical Modeling of Heat and Mass Transfers in an Urban Canyon 14

15 Numerical simulation From building energy simulation (BES) to district scale Surface and volumetric Meshes adapted to BES surfaces : triangular faces 3500 canopy cells: hexaedra Refined meshes needed according to models (solar irradiation, wind airflows) Groset al. (2013) Efficient building models (reduced order) and database management (GIS, ) 15

16 Energyperformance of an urban district Housing(40) School(4) Technical(11) Sport(1) Sport (2) A. Gros(2013) 16

17 Microclimate Analysis Solar flux (kwh/m²/year) Flow patterns at Z=1,5 m A. Gros(2013) 17

18 Numerical simulation Coupling models for urban microclimate and BES North Number of degree-hours higher than 26 C for urban cell located between 3m and 6m height Gros et al. (2013) 18

19 Cool roofs and façades Cool roofs case studiesin Europe and in France atbuilding scale Reference roof Roof refurbishment Cool roof Local direct + indirect effects (envelope, systemsand ventilation cooling) M. Doya et al. (2011) Direct impact of cool roofs is efficient on building taking into account their inertia and combines well with other passive cooling solutions Lapisa et al Ground thermal inertia account for 59% of cool roof effect considering indoor comfort difference without inertia (DH - commercial building France) NV > 80% drop of summer discomfort NV + Cool roofs > 99% drop 19

20 Cool roofs and façades Cool façades and cool roofs effects combining direct + indirect Indirect effects are well evaluated with strongly coupled models UHI <-> BES Different approaches are possible considering timescales: Peak loads can be assessed for extreme and short periods Building energy and ambient temperatures and thermal comfort can be assessed for a whole season A. Gros(2013) 20

21 Impact of green roofs North North Reduction of degree hours above 26 C (%) ( 6m<Z<9m) Reduction of cooling needs (%) Réduction du nombre de degrés-heures supérieurs à 26 C (%) ( 0 m<z<3m) A. Gros(2013) 21

22 Coupling scales or integrated Models from component to building and district scale Envelope green component scale (vegetal canopy) Modeling hygro-thermal and mass transfer Dynamic of water content and transfer in the wall (substrate) Building detailed model (multizone) Street canyon interactions District scales with 3D models 22

23 Challenges: Improve the confidence in predictions Many sources of errors and/or uncertainties : Uncertainties on the data: geometry, construction data, physical characteristics of material, Quality of the physical model : radiation, convection, air flow patterns, coupling with different time constant phenomena (thermal bridges, ground, ), Quality of the meteodata used (Meteonorm, reference year, local measurements.) Non deterministic features (human interaction,.) A real demand of qualification of simulation results does exist (performance contract) A need to develop a more user centered modeling in order to take into account its behavior, exposure, overall comfort, 23

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