climate control and hvac simulation for occupied...

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Climate control and HVAC simulation for occupied spaces Implementation and validation

Eugene de Villiers

22.06.2010

5th OpenFOAM Workshop, Chalmers, Gothenburg, Sweden, June 21-24, 2010

Contributors

• Engys Ltd., London, UK

Dr. Eugene de Villiers, e.devilliers@engys.eu

Dr. Andrew P. Jackson, a.jackson@engys.eu

Francisco Campos, f.campos@engys.eu

• Engys UG, Rostock, Germany

Thomas Schumacher, t.schumacher@engys.eu

• Beuth Hochschule für Technik Berlin, Germany

Thomas Tian, tian@beuth-hochschule.de

Content

• Introduction to Engys

• CFD for HVAC

• HVAC with OPENFOAM®

Basic approach

Validation cases

Examples

• Future Work

OPENFOAM® is registered trade mark of OpenCFD Ltd.

Company Details

• Offices: UK and Germany

• Open Source software for industrial application

• Offering OPENFOAM related services

Consultancy

Training

Support

Custom development

CFD for HVAC

Turbulent flowConvective heat transfer

BuoyancyThermal radiation

Solar radiationHumidity / CondensationContaminant transport

Comfort predictionPhysiological modellingConjugate heat transfer

Built environment

Transportation

Component cooling

Manufacturing

HVAC in FOAM | Basic Approach

• Incompressible flow solver

RANS, URANS, LES

• Integrated properties for incompressible

• r, a, Prt, Cp,

Temperature transport

• Thermal wall functions

• Kader, Jayatilleke

Boussinesq approximation for buoyancy

HVAC in FOAM | Basic Approach (cont.)

• Radiation

Customised non-participating grey FVDOM

• Implemented as function object

• Reduced memory consumption by ~30%

• 1st order explicit marching-front solver

• 5 -10x faster

Solar radiation function object

Temperature coupled boundaries

• Iterative solution of Tw ,Tw

Qconv + Qrad-e = Qsolid + Qrad-a + Qlatent + Qsolar

HVAC in FOAM | Basic Approach (cont.)

• Passive scalar transport

Humidity, smoke, contaminants

Surface condensation/evaporation

• Droplet area model

• Latent heat thermal coupling

• Comfort assessment

ISO 7730 → PMV, PPD, DR, PD

Age of air

ISO 14505-2 → Equivalent temperature

16 zones human model

Validation | Natural Convection

• Experiments by Betts and Bokhari (2000)

• 2D closed vertical cavity

• Ra = 8.6 ∙ 105

yW=0.076m

HOT WALL

T = 34.7ºC

COLD WALL

T = 15.1ºC

Vertical velocity: Uy

Validation | Natural Convection (cont.)

• Experiments by Betts and Bokhari (2000)

• 2D closed vertical cavity

• Ra = 8.6 ∙ 105

yW=0.076m

HOT WALL

T = 34.7ºC

COLD WALL

T = 15.1ºC

Temperature: T

• Experiments by Restivo(1979)

• 2D rectangular cavity

• Reh = 5000

Validation | Forced Convection

INLET→ U0 = 0.455m/s

h = 0.168m

OUTLET

t = 0.48m

Ux/U0 @ X=3m

• Reh = 5000

Validation | Forced Convection (cont.)

h = 0.168m

OUTLET

t = 0.48m

Ux/U0 @ X=6m

• Reh = 5000

Validation | Forced Convection (cont.)

Y = 0.084m

Y = 2.916m

h = 0.168m

OUTLET

t = 0.48m

• Experiments by Blayet.al (1992)

• 2D square cavity

Validation | Mixed Convection

U = 0.57m/s

T = 15ºC

h = 0.018m

OUTLET

t = 0.024m

H = L = 1.04m

T = 35.5ºC

T = 15ºC

Temperature @ X=L/2

• Experiments by Blayet.al (1992)

• 2D square cavity

Validation | Mixed Convection (cont.)

Y = H/2

U = 0.57m/s

T = 15ºC

h = 0.018m

OUTLET

t = 0.024m

H = L = 1.04m

T = 35.5ºC

T = 15ºC

Temperature @ Y=H/2

Validation | Standing Manikin

• Experiments by Nielsen, Kato, Yang et.al (2003)

• Displacement ventilation

• Supply → U = 0.182m/sT = 21.8 °C

• Manikin → Q = 76W

Validation | Standing Manikin (cont.)

• Air temperature profiles

Validation | Standing Manikin (cont.)

• Thermal radiation effects

Radiation OFFRadiation ON

Example | Aircraft Cabin and Cockpit

• Mixed ventilation

• Buoyancy

• Thermal Radiation

• Solar radiation

Example | Generic Aircraft Cockpit

• Windshield defogging

Initial liquid water content on windshield evaporated by dry, hot air from windshield air inlet

Example | Generic Aircraft Cockpit (cont.)

• Smoke evacuation

Transient flow, passive scalar for smoke

Example | Classroom Ventilation

• Comfort assessment → PMV, PPD

Future

• Transient conjugate heat transfer

Face based 1D solid modelling

Automatic 3D thin-solid modelling

• Self-scaling surface-to-surface radiation

• Human physiological models

Coupled multi-node, sweating/shivering

• Smoke

Source modelling

Visibility index

Acknowledgements

• Thanks to Dr. J-H Yang (Yeungnam University) for providing the standing manikin geometry

• Thanks to Dr. A Musser and Dr. K McGrattan for providing experimental results for Blay’s 2D cavity

Disclosure

The contents of this document may not be copied, reproduced,translated, transferred, or reduced to any form, in whole or in part,including electronic medium or machine-readable form, ortransmitted or publicly performed by any means, electronic orotherwise, without written authorisation issued by Engys.Unauthorised distribution or use may give rise to a claim fordamages and/or be a criminal offence as subjected to the laws ofEngland, Scotland and Wales.

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