Ventilated facades design in hot climate.pdf
Transcript of Ventilated facades design in hot climate.pdf
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Ventilated facade design in hot
and humid climate
Ventilated facade design in hotVentilated facade design in hot
and humid climateand humid climate
Matthias Haase
Dr. Alex Amato
Department of ArchitectureFaculty of Architecture
The Hong Kong UniversityPokfulamRoad, HK, China
September 2006
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Ventilated facade design in hotand humid climate
Ventilated facade design in hotVentilated facade design in hot
and humid climateand humid climate
Background Principles
Case studies
Simulation Analysis
Results
Conclusions
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BackgroundBackground
Need for sustainable development Key role of Building industry
Image credits: Behling, S. Sol power - Theev o lut io n o f So la r Arc hitec ture, 1996, Prestel
Energy consumption (world-wide)
Industry
Transport
Building
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BackgroundBackground
Energy responsible approach
Edited by Mat Haase, Image credit:http://www.emsd.gov.hk
Energy consumption (Hong Kong)
Industry
Transport
Building
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BackgroundBackground
Energy in buildings in HK
Edited by Mat Haase, Image credit:http://www.emsd.gov.hk
Ener gy consumption (Hong Kong)
Commerci
al
34%
Industry
12%
Transport36%
Residential
18%
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Energy consumption (Hong Kong)
Lighting
11%
Air -con
16%
Transport,
Sanitaryand
others 7% Industry
Transport
Residential
BackgroundBackground
Energy in buildings in HK
Edited by Mat Haase, Image credits:http://www.emsd.gov.hk andhttp://arch.hku.hk/research/BEER/besc.htm
Energy consumption in officeBuildings in HK
Transport,
Sanitary,others 21%
Air-con
47% Lighting32%
27% of energy in HK is consumed by Air-con and Lighting in commercial buildings
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Faade
technology
Sun protection/shadowing
Ventilation
Photo-voltaics
Heating/cooling
Passive solar
Daylight
Acousticprotection
Insulation
BackgroundBackground
Possible integrated functions
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BackgroundBackground
New concepts for sustainable buildings Double-skin facades for office buildings
left: Multimedia Center, Hamburg, Germany by Foster and Partnersright: Uni, Erlangen, Germany by UBA ErlangenImage credit: http://www.fosterandpartners.com
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BackgroundBackground
Why double-skin faades?
55.6%
Peak cooling load of
office building in HK
Lam, J . C. and Li, D. H. W. (1999) An analysis of daylighting and solar heat for cooling-dominated office buildings.Solar Energy, 65, 251-262.
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BackgroundBackground
Why double-skin faades?
Reduction of peak wind pressure
Improvement of energy efficiency of
faade by
passive solar heat gain in winter
reducing thermal losses in winter reducing overall solar heat gain
(in summer)
support of natural ventilation
(with the stack effect)
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BackgroundBackground
Why double-skin faades?
Improving comfort
Thermal: - predicted mean vote (PMV)
- percentage people dissatisfied (PPD)
- draft temperature
Visual: - daylight factor
- glare- view
Acoustic: - intrusive noise
Image credits: Thermal comfort, INNOVA AirTec instruments and MatHaase
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BackgroundBackground
Classification of double-skin faades (DSF)
Box windowfacade
Corridorfacade
Shaft-box windowfacade
Multi-storeyfacade
Cavityventilation
natural mechanical
Airflowconcept
External
air curtain
Supply air Exhaust
air
Internal
air curtain
Main Type
Static air
buffer
hybrid
Haase, M., Amato, A., (2005), Double-skin facades for Hong Kong, proceedings of the Fifth International Postgraduate ResearchConference in the Built and Human Environment, The University ofSalford, UK.
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Principles of DSFPrinciples of DSF
Principles of airflow in cavity
External
air curtain
Supply airExhaustair Internal
air curtain
Static air
buffer
ext.ext.int. int.
open notopen
int. int.int.ext.
Haase, M., Amato, A., (2005), Double-skin facades for Hong Kong, proceedings of the Fifth International Postgraduate ResearchConference in the Built and Human Environment, The University ofSalford, UK.
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BackgroundBackground
Heat transfer
Radiation Q12 = A1 12 T14 - T24)
Conduction Q = A ( T1 - T2 ) / t
Convection
Q = hc A T
Traditional performance criteria U-value, SHGC, meaningless
Reflexion
Conduction and ConvectionConduction and Convection
Second glass layerprimary facade
Qin
Qout
Absorption
Transmission
Transmission
NN11NN22
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22
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BackgroundBackground
Building design concept
Haase, M. and Amato, A., (2005), Development of a double-skin facade system that combines airflow windows with solar chimneys,proceedings of Sustainable Building Conference (SB05), Poster session, Tokyo, J apan.
Energyconservation
Increasingefficiency
Utilization of renewableenergy resources
Building energy consumption
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BackgroundBackground
Energy conservation
0
5
10
15
20
25
30
35
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
degrees
0
1000
2000
3000
4000
5000
6000
7000
8000
degreehou
rs
min/max temperature heating degree hours
solar excess degree hours cooling degree hours
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Climate analysisClimate analysisClimate analysis
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Climate analysisClimate analysisClimate analysis
Dry bulb temperature [C]
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Climate analysisClimate analysisClimate analysis
Dry bulb temperature [C]
Abs.Humidity[AH]
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Climate analysisClimate analysisClimate analysis
Dry bulb temperature [C]
Abs.Humidity[AH]
Rel.humidity
[rel.hum]
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Climate analysisClimate analysisClimate analysis
Dry bulb temperature [C]
Abs.Humidity[AH]
Enthalpy
[h]
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Climate analysisClimate analysisClimate analysis
Dry bulb temperature [C]
Abs.Humidity[AH]
DBT(C) 5 10 15 20 25 30 35 40 45 50
AH
5
10
15
20
25
30
Comfort
Psychrometric ChartLocation: Hong Kong, ChinaFrequency: 1st January to 31st December
Weekday Times: 00:00-24:00 HrsWeekend Times: 00:00-24:00 HrsBarometric Pressure: 101.36 kPa
A.J.Marsh '00
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Climate analysisClimate analysisClimate analysis
DBT(C) 5 10 15 20 25 30 35 40 45 50
AH
5
10
15
20
25
30
Comfort
Psychrometric ChartLocation: Hong Kong, ChinaFrequency: 1st January to 31st DecemberWeekday Times: 00:00-24:00 Hrs
Weekend Times: 00:00-24:00 HrsBarometric Pressure: 101.36 kPa A.J.Marsh '00
SELECTED DESIGN TECHNIQUES:1. exposed mass + night-purge ventilation2. natural ventilation3. direct evaporative cooling
4. indirect evaporative cooling
Selected energySelected energyconservationconservation
designdesign
strategiesstrategies
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Climate analysisClimate analysisClimate analysis
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Case studiesCase studies
Case studies of existing DSF in Hong Kong:
1. Dragon Air office building, Lantau
2. Kadoorie Biological Science Building, HKU
3. Science Park (Phase 1), Pak Shek Kok
4. Governmental offices, Shatin
5. No. 1 Peking Road, Kowloon
6. New emsd hq, Kai Tak
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Case studiesCase studies
Double-skin faade(external air curtain)
Double-skin cavity actsas external shadingdevice
Sealed faade withcavity externallynaturally vented
Image c redit: Meinhardt FacadeTechnology
(as in Dragon Air office andin Science Park)
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Case studiesCase studies
Example of DSF with EAC:
Science Park (Phase 1) by Simon Kwan
Building here: with PV integrated
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Case studiesCase studies
Example of DSF with EAC:
Kadoorie Biological Science building by Leigh & Orange
Building here: with HVAC system components in cavity
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Case studiesCase studies
Airflow window(internal air curtain)
ShatinGovermental Offices
No. 1 Peking Road
New emsd hq
Image c redit: Meinhardt FacadeTechnology
one room
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Case studiesCase studies
Airflow window(internal air curtain)
Heat is concentrated in cavity
10% exhaust air: savings in overall
cooling energy possible
Improving thermal comfort
AHU
Exhaust air
Second
glass layer
Visibleglass
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Case studiesCase studies
Example of AFW with IAC: ShatinGovernmental Office by ASD Active window (developed by MeinhardtFaade Technology)
Image credits: HK Construction Ltdhttp://202.66.146.82/listco/hk/hkconstruction/
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i l iSi l i
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SimulationSimulationSimulation
double-skin facadesbasecase DSF AFW
Si l iSi l iSi l ti
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SimulationSimulationSimulation
double-skin facadesbasecase DSF AFW
Internalglasslayer
Externalglasslayer
Internalmovableblinds
Spandrel
panel
AHU
Internalglasslayer
External
glasslayer
Internalmovableblinds
External
glasslayer
Internalmovableblinds
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Si l tiSi l tiSi l ti
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SimulationSimulationSimulation
Thermalbuilding simulation coupled withairflow
simulation
AFW
Si l tiSi l tiSimulationFaade 3
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facade 1
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
12 18 30 42 54 66 78 90 102 108
height
Cp
0
45
90
135
180
225
270315
Cp over height
winddirection
SimulationSimulationSimulation
Faade 1
Faade 2
Faade 4
DSF2DSF2--22DSF2DSF2--33 DSF2DSF2--44
SimulationSimulationSimulation 0 200 400 600 800 1000
cooling load (kWh)
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Results
Monthly results for simula tion o f DSF a t
d i fferent he ights
SimulationSimulationSimulation JanFeb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
basecase with reflective glass basecase solar control glass
DSF1 DSF2-1DSF2-2 DSF2-3
DSF2-4
Control strategiesControl strategiesControl strategies
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Control strategiesControl strategiesControl strategies
Controlling solar radiation
Controlling HVAC
Controlling exhaust airflow using
a climate sensitive regulator
Movable
louvres
Visibleglass
AHU
>200W/m>200W/m
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Climate sensitive regulatorClimate sensitive regulatorClimate sensitive regulator
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Climate sensitive regulatorClimate sensitive regulatorClimate sensitive regulator
AA
BB
CC
DD
Enthalpy balance
Haase, M. and Amato, A., (2005), Double-skin facades for Hong Kong, proceedings of the Fifth InternationalPostgraduate Research Conference in the Built and Human Environment, The University of Salford, UK.
SimulationSimulationSimulation
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Results
Monthly sim ula tio n results for DSF a nd AFW with a nd
wi thout c lim ate c ont ro l
SimulationSimulationSimulation
0
100
200
300
400
500
600
700
800
900
1000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
coolingload(kWh)
bas ecas e DSF1 DSF2
AFW1 AFW2
with climate control
without climate control
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SimulationSimulationSimulation
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Results
Simula tion re sults for ba sec a se , DSF a nd AFW
SimulationSimulationSimulation
0%
5%
10%
15%
20%
25%
30%
baseca
se(internals
hading)
baseca
sewith
refle
ctive
glass
basecases
olar
controlg
lass
DSF1-1
DSF1-2
DSF2-1
DSF2-2
annual
3 hottest months
hottest month
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ConclusionsConclusionsConclusions
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ConclusionsConclusionsConclusions
Planned future work
Validation with measured data
Detailed daylight analysis
Solar assisted extract air device
LCA of different faade systems
Ventilated facade design inhotVentilated facade design in hotVentilated facade design inhot
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Ventilated facade design in hot
and humid climate
Ventilated facade design in hotVentilated facade design in hot
and humid climateand humid climate
Background
Simulation Analysis
Results
Conclusions
Thankyou
ThankThank
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http://thegreenroom.arch.hku.hk