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
Copyright © 2010 Engys Ltd. All rights reserved.
Contributors
• Engys Ltd., London, UK
Dr. Eugene de Villiers, [email protected]
Dr. Andrew P. Jackson, [email protected]
Francisco Campos, [email protected]
• Engys UG, Rostock, Germany
Thomas Schumacher, [email protected]
• Beuth Hochschule für Technik Berlin, Germany
Thomas Tian, [email protected]
Copyright © 2010 Engys Ltd. All rights reserved.
Content
• Introduction to Engys
• CFD for HVAC
• HVAC with OPENFOAM®
Basic approach
Validation cases
Examples
• Future Work
Copyright © 2010 Engys Ltd. All rights reserved.
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
Copyright © 2010 Engys Ltd. All rights reserved.
CFD for HVAC
Copyright © 2010 Engys Ltd. All rights reserved.
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
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xgpPp
TTTgS
mref
mmmmb
r
rrrr
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
Copyright © 2010 Engys Ltd. All rights reserved.
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
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Validation | Natural Convection
• Experiments by Betts and Bokhari (2000)
• 2D closed vertical cavity
• Ra = 8.6 ∙ 105
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x
yW=0.076m
H=
2.1
8m
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
Copyright © 2010 Engys Ltd. All rights reserved.
x
yW=0.076m
H=
2.1
8m
HOT WALL
T = 34.7ºC
COLD WALL
T = 15.1ºC
Temperature: T
• Experiments by Restivo(1979)
• 2D rectangular cavity
• Reh = 5000
Validation | Forced Convection
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INLET→ U0 = 0.455m/s
h = 0.168m
OUTLET
t = 0.48m
L=9m
H=3m
x
y
Ux/U0 @ X=3m
• Experiments by Restivo(1979)
• 2D rectangular cavity
• Reh = 5000
Validation | Forced Convection (cont.)
Copyright © 2010 Engys Ltd. All rights reserved.
INLET→ U0 = 0.455m/s
h = 0.168m
OUTLET
t = 0.48m
L=9m
H=3m
x
y
Ux/U0 @ X=6m
• Experiments by Restivo(1979)
• 2D rectangular cavity
• Reh = 5000
Validation | Forced Convection (cont.)
Copyright © 2010 Engys Ltd. All rights reserved.
Y = 0.084m
Y = 2.916m
INLET→ U0 = 0.455m/s
h = 0.168m
OUTLET
t = 0.48m
L=9m
H=3m
x
y
• Experiments by Blayet.al (1992)
• 2D square cavity
Validation | Mixed Convection
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INLET
U = 0.57m/s
T = 15ºC
h = 0.018m
OUTLET
t = 0.024m
H = L = 1.04m
x
y
FLOOR
T = 35.5ºC
WALLS
T = 15ºC
Temperature @ X=L/2
• Experiments by Blayet.al (1992)
• 2D square cavity
Validation | Mixed Convection (cont.)
Copyright © 2010 Engys Ltd. All rights reserved.
Y = H/2
INLET
U = 0.57m/s
T = 15ºC
h = 0.018m
OUTLET
t = 0.024m
H = L = 1.04m
x
y
FLOOR
T = 35.5ºC
WALLS
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
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Validation | Standing Manikin (cont.)
• Air temperature profiles
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Validation | Standing Manikin (cont.)
• Thermal radiation effects
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Radiation OFFRadiation ON
Example | Aircraft Cabin and Cockpit
• Mixed ventilation
• Buoyancy
• Thermal Radiation
• Solar radiation
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Example | Generic Aircraft Cockpit
• Windshield defogging
Initial liquid water content on windshield evaporated by dry, hot air from windshield air inlet
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Example | Generic Aircraft Cockpit (cont.)
• Smoke evacuation
Transient flow, passive scalar for smoke
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Example | Classroom Ventilation
• Comfort assessment → PMV, PPD
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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
Copyright © 2010 Engys Ltd. All rights reserved.
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
Copyright © 2010 Engys Ltd. All rights reserved.
Disclosure
Copyright © 2010 Engys Ltd. All rights reserved.
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.