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



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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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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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


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


Possible integrated functions


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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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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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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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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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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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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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33

22

11


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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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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Dry bulb temperature [C]


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Abs.Humidity[AH]


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Abs.Humidity[AH]

Rel.humidity

[rel.hum]


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Abs.Humidity[AH]

Enthalpy

[h]


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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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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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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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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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Example of DSF with EAC:

Science Park (Phase 1) by Simon Kwan

Building here: with PV integrated


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Example of DSF with EAC:

Kadoorie Biological Science building by Leigh & Orange

Building here: with HVAC system components in cavity


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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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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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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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double-skin facadesbasecase DSF AFW

Internalglasslayer

Externalglasslayer

Internalmovableblinds

Spandrel

panel

AHU

Internalglasslayer

External

glasslayer


External

glasslayer



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Si l tiSi l tiSi l ti


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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


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.



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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


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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Results

Simula tion re sults for ba sec a se , DSF a nd AFW


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



Background

Simulation Analysis

Results

Conclusions

Thankyou

ThankThank

youyouQs?Qs?

http://thegreenroom.arch.hku.hk

Ventilated facades design in hot climate.pdf

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