AKOESTIEK LAWAAIBEHEERSING BOUWFYSICA MILIEUTECHNOLOGIE

Advances in combined building thermal simulation and prediction of air-flows with Phoenics

Eindhoven 24th May 2005 Zoetermeer (NL) Mook (NL) Düsseldorf (D) Paris (F) www.peutz.nl

Auteur/spreker Ir. Marcel van Uffelen

Introduction

 Evermore large glazed spaces like atria  Atria complex shaped and laid out with a sophisticated HVAC concept  High demands on interior climate posed throughout the whole year  Overheating during significant part of year  Cold downdraughts during winter

Advances in combined building thermal simulation and prediction of air-flows with Phoenics

Introduction

 To compute and analyse these effects Peutz BV in the Netherlands have developed a special software program that makes it possible to perform dynamical thermal building simulations combined with an integrated air-flow computation with Phoenics 3.5

Advances in combined building thermal simulation and prediction of air-flows with Phoenics

Introduction

 For offices, atria and coupled spaces  Advantages to TRNSYS/TAS etc: detailed solution of vertical temperature gradients for instance  Advantages to traditional CFD computation: ease of automatic control of varying solar irradiation, internal and external shading by buildings and constructions, HVAC control and varying internal heat gains

Advances in combined building thermal simulation and prediction of air-flows with Phoenics

Approach of simulation

 Phoenics model of the entire building or atrium  Transient model, to properly deal with floor and wall temperatures (taking into account inert masses  Several dedicated input screens for input data concerning HVAC control, g-values and internal heat gains

Advances in combined building thermal simulation and prediction of air-flows with Phoenics

Technics

 ‘surface-to-surface radiation’ model automatically computes view-factors etc. in building or atrium  Internal and external shading discerning windows, diffuse and direct solar radiation and sun-blinds. For that purpose the ray tracing method is applied.

 Heat transfer coefficients by empirical formulas. Computations more reliable, stable and faster in this manner

Advances in combined building thermal simulation and prediction of air-flows with Phoenics

Validation

 Differences ½ K  Larger vertical temperature gradient predicted by the CFD model  Less mixing of cold and hot air  Hot air shows a tendency towards streaming directly upwards in the shape of a plume, creating a layer under the ceiling  Risk of overheating on foot-bridges or galeries at the highest floors

Advances in combined building thermal simulation and prediction of air-flows with Phoenics

Projects

 New Sittard headquarters Sabic  six office floors and central void  glazed facade with solar glazing combined with interior sun-blinds as well as a glazed atrium roof  prevent large-scale air-movements  vertical temperature gradient be limited  increase cooling capacity upper floors close the boardrooms at the sixth level along the north west facade increase cooling capacity

Advances in combined building thermal simulation and prediction of air-flows with Phoenics

Projects

 Atria headquarters CC Bank M’gladbach  atria interconnected by wide and high corridor  purpose to minimise draught phenomena  study different shading devices facade lay-outs solar  effect of a chilled ceilings underneath the galeries around the atria and chilled floor subject of research  during winter sufficient reduction of the cold down-draughts by means of heated ribbed tubes

Advances in combined building thermal simulation and prediction of air-flows with Phoenics

Projects

Glazed gallery Antwerp ‘Museum Aan de Stroom’   nine level glazed gallery surrounding the museum in the shape of a helix ‘half-climate’  single pane glazing in the facades of the gallery  exhaust of spill air from exhibition spaces  chilled floors  half-transparent highly reflective automatic interior sun-screens  night-ventilation  under-pressure in the exhibition spaces

Advances in combined building thermal simulation and prediction of air-flows with Phoenics

Projects

 natural ventilation through operable windows, exhaust through automatically controlled louvers in the roof  atrium rises several meters above roof to augment thermal stack-effect and avoid stagnant hot air at upper laboratory floors  thermally open ceilings, night-ventilation, fixed wooden outside sun-blinds   automatically close windward louvers top atrium atrium no operable louvers to avoid ‘short-circuit’

Advances in combined building thermal simulation and prediction of air-flows with Phoenics

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Conclusions

Striking features:  solar glazing, sun-blinds, local chilled ceiling or floor, shifting air supply quantities or density of chilled ceilings, often will do  Nevertheless, considerable improvement of thermal comfort  program significantly extents range of spaces and HVAC-concepts that can be properly modelled and simulated  substantial gain in quality and confidence at reasonable costs  automation and quality control result in complete thermal building simulations with CFD at reasonable prices

Advances in combined building thermal simulation and prediction of air-flows with Phoenics