Presentation is loading. Please wait.

Presentation is loading. Please wait.

Reduced-Order Models for Building Interzonal Transport EPA04 T3.2

Similar presentations


Presentation on theme: "Reduced-Order Models for Building Interzonal Transport EPA04 T3.2"— Presentation transcript:

1 Reduced-Order Models for Building Interzonal Transport EPA04 T3.2
Jensen Zhang, John Grunewald, Andreas Nicolai, Hui Li, H. Ezzat Khalifa, Basman Elhadidi, and John Dannenhoffer, III Syracuse University

2 Envisioned i-BES Occupant Satisfaction: ~100% >90% >80%
Envelope system Material selection HVAC system Room air cleaner Room ventilation Personal ventilation Smart furniture Wearable air purifier Occupant Satisfaction: ~100% >90% >80% 80% (ASHRAE Standards) Occupant Personal Env. Zone/ Room Multizone Building Outdoor Airshed Multi-level Controls: 3 2 1 IEQ Building Security Energy Efficiency Goals:

3 The Problem and Research Needs
i-BES control requires real/near real time prediction of pollutant transport Reduced-order models Efficient coupling of different component models Need-based multi-level/scale modeling Integrated BES design and optimization IEQ Energy Cost-effectiveness Exposure/performance prediction at different stages of building system design Single zone 2-5 zones Detailed multizone analysis Spatial distribution analysis (CFD)

4 Interactions between CHAMPS Component Models
CHAMPS-BES/simplified & EnergyPlus POD/CFD EnergyPlus/simplified CHAMPS-Multizone (CONTAM +) Heating, cooling & pollutant loads Envelope Model HVAC Model Rates of H. A. M. P. through structures via the source terms Q, T, and RH of supply air Interior pressure Multi- zone Model B.C.’s on Room surfaces Q, T, and RH of supply air Mixing level and zone dynamics Room Model *Databases: Material Properties; Pollutant Properties; Sources & Sinks; Weather

5 Research Objectives The Ultimate Goal:
Develop reduced-order models that can be used for BES analysis, optimization and control (T5). Specific Objectives for EPA04 Project (3 years): CHAMPS-Multizone (EPA04) Pollutant and thermally-induced airflows Multizone and envelope model coupling Multizone and room model coupling Reduced-order room model Model validation: a case study

6 Development and applications of CHAMPS
Roadmap EPA03 EPA04 2004 2005 2006 2007 2008 Development and applications of CHAMPS New emphases: Pollutant flows Simpler models Coupling CHAMPS-BES 1.0 Material & VOC database procedure Delphin (7+ years) Material & VOC database CHAMPS-Multizone CHAMPS/e+ coupling CHAMPS/POD coupling Case study

7 In response to the SAC06 review
SAC comments CHAMPS model is too complex and overkill How different is this effort from the others? Actions Build upon well-known existing models Focus on knowledge gaps Effects on pollutant flows Reduced-order/simpler models Efficient coupling between models Enhance networking with other key players CHAMPS workshop in June 2006 E+ developers, educator’s workshop, July 2007 CHAMPS forum in BS07, Beijing, China, September 2007

8 Presentations in this Review
Overview (5 minutes) CHAMPS Multizone Development Roadmap and Preliminary Results (10 minutes) Application of Proper Orthogonal Decomposition to Indoor Airflows (5 minutes) Posters: CHAMPS-Multizone model development and applications (by J. Grunewald, A. Nicolai and J. Zhang) POD model development and applications (by E. Khalifa, B. Elhadidi and J. Dannenhoffer)

9 CHAMPS Multizone Development Roadmap and Preliminary Results
John Grunewald, Andreas Nicolai, Jensen Zhang, H. Ezzat Khalifa, Basman Elhadidi and John Dannenhoffer, III Syracuse University

10 Definition of the Challenge
Air Spaces VOC emissions from interior sources (furniture, equipment,…) Air change rate (indoor-outdoor) in zones Pollution of outdoor air Interzonal air flows Zonal air flow (forced convection, buoyancy) VOC emissions from Building Envelope Systems (BES) Heat and moisture transmission through BES Air flows through BES (leakage, flux in small air spaces) BES Challenge: Coupling of heat and mass transport in Air Spaces and in Building Envelope Systems (porous materials)

11 About Air Flows How do different programs handle air flow calculation?
Air flux input Pressure field calculation Air flow implementation types How do different programs handle air flow calculation? (EnergyPlus, CHAMPS) air change rate, air tightness of BES Interzonal airflow, non- geometric models (CONTAM) Zonal airflow, geometric models, buoyancy (CFD) Airflow in BES, simplified Navier-Stokes, buoyancy (CHAMPS)

12 Model Features Comparison
Indoor air quality = f(VOC, RH and T conditions in zones …) EnergyPlus CONTAM CHAMPS Balances T in zones x - - RH in zones x x x VOC in zones - x x Result: No model can handle all processes! Conclusions: Need to bridge the gaps between the models! 1. EnergyPlus is the model to start with. 2. CONTAM + CHAMPS features need to be combined.

13 Model Features Comparison
EnergyPlus CONTAM CHAMPS Emissions Internal VOC sources - x x (multilayer) x VOC emission from BES x (influence of T, RH) x Pollution from outdoor - x x VOC database - x ? Research needed VOC database with sorption/emission characteristics

14 Model Features Comparison
EnergyPlus CONTAM CHAMPS Airflows Air change rate x x x Air tightness of BES x x x Interzonal air flow x x x Interzonal pollutant flow - x ? Airflow in BES x Airflow in large spaces ? Research needed VOC database with sorption/emission characteristics Couple multizone interzonal airflow with BES Air flows in large spaces Research needed VOC database with sorption/emission characteristics

15 CHAMPS Development Milestones
BES CHAMPS Coupled Heat, Air, Moisture, and Pollutant Simulation 2004 2005 Heat and moisture basis module 2D Air leakage and VOC extension modules EPA03 Multizone CHAMPS Coupled Heat, Air, Moisture, and Pollutant Simulation 2006 EPA04 Heat, moisture and VOC in well mixed zones Coupling to CHAMPS-BES constructions 2007 Zone - outdoor connections (Air flows + T, RH and VOC) Interzonal connections (Air flows + T, RH and VOC) Interface to EnergyPlus / DesignBuilder 2008 Zone discretisation (no well-mixed assumption)

16 CHAMPS-BES Application Example
Example construction to study air flow & VOC effects upward infiltration airflow Release of VOC (Toluene) Infiltration Airflow OSB Board (20 mm) OSB Board (20 mm) © Reprinted with permission from

17 CHAMPS-BES Application Example
CHAMPS run with full BES models VOC-field in log10(mg/m3) BES Air + VOC convection Air + VOC diffusion Air flow Zone

18 CHAMPS-Multizone Application Example
Dual chamber moisture & VOC diffusion (experiment & modeling) Injection air flow (high RH, VOC) Clean air flow (low RH, no VOC) Chamber A B T const Calcium silicate Moisture and VOC diffusion

19 Overview Need for an efficient means to couple the multizone and CFD calculations. Objective: To model, in near-real-time, contaminant distribution in a building consisting of a large number of interconnected zones: Small, well-mixed spaces (offices) Non-uniform open spaces (NOS). Challenge: Network Flow Zonal (NFZ) models (e.g., CONTAMW), are very fast (seconds), but assume that each zone is well-mixed (lumped parameter). Reasonable for small well-mixed rooms; not realistic for large non-uniform spaces. CFD is time consuming (hours to days) and requires considerable computing resources. Provides spatial resolution, but unsuitable for optimization or real-time control. It is not feasible to run both simultaneously in near-real-time for control purposes, or for the large number of iterations needed for design optimization of a complex system.

20 Approach See: Elhadidi & Khalifa, ASHRAE Trans. 111(1), 2005; and Khalifa & Elhadidi, ASHRAE Trans. 113(2), 2007; and the poster later today. Run the CFD simulations offline before-hand over the expected parameter space (generate snapshots). Use Proper Orthogonal Decomposition (POD) to generate a fast-executing, reduced-order representation of the CFD snapshot results: Extract eigen-modes from CFD snapshots; Reconstruct high-fidelity representations of the flow, temperature and concentration fields from these eigen-modes (in seconds). Develop a method for coupling the POD modes with the NFZ model in near-real-time dynamic simulations, or in system design optimization.

21 Original and Reconstructed Concentration Field

22 Results and Conclusions
POD can be used to reconstruct CFD or experimental spatial and temporal results quickly and accurately. The POD-reconstructed CFD results can be efficiently integrated with multi-zone, network-flow models. The integrated POD/CFD and NFZ approach allows efficient optimization and near-real-time control of more complex indoor environments. Ongoing work is addressing transient contaminant dispersion and coupling of temperature fields. At 1.5 m height


Download ppt "Reduced-Order Models for Building Interzonal Transport EPA04 T3.2"

Similar presentations


Ads by Google