May 22, 2012

Moving Towards Sustainable Fenestrations in Kuwait

Essam O. AssemAssociate Research Scientist

Building Energy Technologies Dept.Kuwait Institute for Scientific Research

Outline

• Fenestration facts• Common fenestration parameters• Fenestration elements• Areas influencing fenestration performance• Manufacturing cycle• Requirements for sustainable fenestrations• How to move towards sustainable fenestrations in Kuwait

Fenestration Facts

⇑ They connect the inside with the outside and provide ‘‘life’’ to the building which could increase productivity

⇑ Allow day light to the interior spaces of the building and will reduce if not replace the need for artificial lighting resulting in reductions in energy consumption

⇑ Glazing covers a large area of the façade of tall buildings because of aesthetics and short installation time

⇓ Up to 25% of the peak cooling load is attributed to solar heat gain through fenestrations. This could be higher if air leakage is accounted for

Common Fenestration Parameters

• Thermal transmittance (U-value)• Solar heat gain coefficient (SHGC)• Visible transmittance (VT)

• Air and water permeability• Wind resistance (deflection)• Noise reduction (NR)

Fenestration Elements

Spacer

Glass

Primary Seal

Secondary Seal

Thermal Break

Frame

Gas Fill

Outside Inside

Frames

AluminumAluminum with thermal breaksWoodUPVCVinylFiberglass

Spacer

Spacers

AluminumStainless SteelInsulating silicon foamExtruded vinylFiberglass

Spacer

Glass Panes

Configuration

Single

Double

Triple

Double with suspended

films

Glass Optical Properties

Clear

Tint

Reflective

Low-e

Switchable

Glass Processing

Annealed

Laminated

Toughened

02468

101214161820

Tot

al E

nerg

y (K

Wh)

0.5 1.5 6

Window Area (m2)

clear- double

tinted- double

reflective- double

Gas Fills

Gap widthAirArgonKryptonXenonNone (vacuum)

Air Argon Krypton Xenon1.65

1.7

1.75

1.8

1.85

1.9

1.95

U-F

acto

r (W

/m2.

K)

0 5 10 15 20 25 30 351.75

1.8

1.85

1.9

1.95

2

2.05

2.1

2.15

2.2

Gap Spacing, (mm)

U-f

acto

r, (

W/m

2.K

)

Shading Devices

FixedManualAutomatedBetween the panes of glassExternalInternal

instantaneous blind and lighting control based on

day-lighting intensity

Sash Frames and Weather Striping

Openable windows and doors should be designed to minimize air and water permeability as much as possible

Assumptions:Ten 2m2 sliding windows

Outside: 46C DB

28C WB

Inside: 24C DB

50% RH

0.6 tonref

3.8 tonrefANSI/AAMA standardBased on field

study findings carried out by KISR

Effect of air leakage on cooling load

Sash Frames and Weather Striping … contd.

0

50

100

150

200

250

300

0 5 10 15

Air Infiltration (m3/h/m)D

ust

Co

nte

nt

*10-

6 (g

/m^

3)

International limit

Field measurement from KISR study

Air-tightness of fenestrations can also affect human health particularly in dusty weather conditions

Acoustics

• Maintaining acceptable sound levels within the spaces of the building is essential to minimize occupants stress levels associated with external sources of noise.

• The fenestration performance should also account for noise reduction (NR).

• ANSI S12.40 recommends a yearly day-night average sound level of 45 dB.

Areas Influencing Fenestrations Performance

Fenestration Performance

Comfort

Thermal Visual Acoustic

Thermal

Transmission Solar heat gains

Structural

Air/water permeability Safety/security Condensation Durability

Manufacturing Cycle

Float Glass PlantGlass Coating

(i.e. Low-e)

Glass Processing(cutting, edging,

drilling, tempering, IGU, etc.)

Assembly (i.e frames, sash and weather stripping)

Building Site

High quality silica sand

Average embodied

energy 16 MJ/kg

AluminumSteel

Average embodied

energy220 MJ/kg

Average embodied

energy35 MJ/kg

Requirements for Sustainable Fenestrations

Issues to consider for sustainability:

Social impact: Thermal comfort Visual comfort Health

Economic impact: Direct fuel cost Life cycle of fenestrations

Environmental impact: Float glass Aluminum/Steel etc. Energy consumption Recycling

Optimum Design

Heat Gain

Thermal Comfort

Day Light/visual

comfort

DurabilityCost

Materials

Health &

Safety

How to Move Towards Sustainable Fenestrations in Kuwait

State-of-the-art simulation tools must be used to arrive at the optimum design

Social impact issues must be accounted for through specific codes and standards

Fenestration rating labs must be established to verify their performance (air & water leakage, U-value, SHGC, durability, etc.) and hence improve quality

High performance fenestrations should be a pre-requisite To make use of locally and regionally manufactured fenestrations

(float, coating and processing) vis-à-vis LEED 500 miles To have in place the infrastructure to support recycling of

fenestration materials

Thank You