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F FPeople like natural light


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F F

Are you wasting 20% of your electricityusage?

Are Your lights on during daylighthours?

Lights on Blinds Down= Bad Design


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F FSummary of Presentation

• What is daylight design• Where does daylight design sit within

sustainable building design• Worked example of daylight design• Sunlight and daylight design products• Typical case studies• Conclusions


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F FThe Headlines

• Electric Lighting Currently consumes 19% ofcurrent total global electricity production thisequates to 1.9 Gt of CO2/yr. If currentenergy efficiency polices do not changeelectric lighting will increase to consume 3 Gtof CO2/yr by 2030

IEA/OECD Lights Labours Lost 2006

• There is no viable alternative to electriclighting during darkness hours that meetscurrent design standards.


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F FGraphs 1

According to the International Energy Agency the savings in electrical energy could reach2380 TWh per annum against the current projected lighting electrical load of which gooduse daylight represents approximately 50% of the possible savings.

IEA/OECD lights labours lost 2006


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F FRegulations, Standards and Guides

Regulations• European workplace directive - Access to daylight required• Building Regulations - No minimum daylight standards

Standards• BS 8206-2 2008 Code of Practice for daylighting. 2-5% DF ave Uo 0.7• BREEAM 2008 HW 1 2% DF (1pt) Exemplar 3% DF (1pt) HW 2

view out (1pt) Glare control (1pt).• Building Bulletin 87 Guidelines for environmental design in schools

3-4% DF ave Uo 0.3-0.4 and 0.7 for rooflights• Lighting design for schools Building Bulletin 90

2-5% DF ave Uo 0.3-0.4 and 0.7 for rooflights• Designing schools for the future Building Bulletin 95

3-4% DF ave Uo 0.3-0.4 and 0.7 for rooflights.• CIBSE LG2 Lighting for Healthcare buildings

Guides• CIBSE SLL Daylighting and window design LG10 1999• BRE Designing buildings for daylight.• BRE Designing with innovative daylighting


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F FDaylit architecture


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F FDaylight design 1

• What is Natural Light? There are two components to natural light,direct solar radiation (sunlight) and diffuse sky radiation (skylight). We useskylight predominantly in design

• What are the differences between artificial light andnatural light ? The properties of natural light, full electromagneticspectrum, Dynamic with changes in colour, direction and intensity.

• How do we achieve optimal daylight design? Buildingsfacades are modelled so as to perform optimally with the ambient natural light as wellas thermally

• How does building layout affect daylight? The buildingmass and the internal layout has to maximise the use of natural light. Shallow planbuildings are preferred ( 15m wide). Deep plan buildings require careful design

• Does it matter which way the building faces? BuildingOrientation is not critical on an open site but adjacent buildings must be consideredon an enclosed site


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F FDaylight design 2

• What are the health benefits of daylight? Daylight relievesSeasonal Affected Disorder SAD and regulation of Circadian rhythms andpsychological mood.

• How do we calculate daylight? The historical method of calculatingdaylight has been average daylight factor (DF) there is also now the usabledaylight illuminance (UDI). Which has growing support amongst daylightpractitioners but is not yet part of the recognised standards.

• How Much daylight do we need? To supplement the need forartificial lighting 2% DF to replace artificial lighting to 5% DF

• What are the constraints on daylight? Daylight usage isconstrained by thermal performance of the overall façade, direct solar glare andlimiting variance in uniformity.

• Where and which business sectors is appropriatedaylight design? Almost all business sectors can benefit from daylightdesign in some aspect is applied to all buildings if you have openings in the buildingfabric someone has done some level of daylight design.


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F FWhere does daylight sit with sustainability &

sustainable design

• Daylight like all sustainability techniques needs to deliverthe triple bottom line of social, economic andenvironmental benefit.

• All project team members need to be involved and agreeto the decision to procure a daylight design by the end ofstage B and relevant costs, programme implications andfees advised and agreed.

• To achieve optimal daylight design the all key decisionsneed to be complete by the end of RIBA stage C.

• Contractual methods need to be carefully chosen as itunlikely that optimal sustainable designs can be achievedthrough design and build, PFI, and PPP procurementmethods


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F FDaylight for health

• Daylight has been proven to aid recovery inpost operative situations.

• Daylight alleviates Seasonal Affected Disorder(SAD) and the milder form S-SAD.

• Daylight helps the regulation of Circadianrhythms.

• Psychological mood• Daylight improves attentiveness especially in

children.


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F FCircadian Rhythms

Levels of Attentiveness over a 24 Hour period

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5

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12 15 18 21 24 3 6 9 12

daytime in hours (24)

Atte

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s (t

ime

in m

inut

es to

fall

asle

ep)

dangerous need for sleep

reduced attentiveness

slightly reduced

highest attentiveness

Photobiological Effects

0

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400 450 500 550 600 650 700Wavelength (nm)

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Sleep patterns

Hormone Production

Eye’s response to light


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F FThe secret to delivering savings

• Daylight needs to be designed in conjunctionwith the HVAC electrical and Architecturaldesign.

• The correct artificial lighting design needs to beconsidered in conjunction with the daylightdesign.

• Intelligent lighting controls are an essentialcomponent of daylight design.

• The correct contractual procurement methodneeds to be entered into to deliver the optimaldesign.


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F FGraphs 2

Fluorescent digital dimming ballasts such as DALI or DSIcan save up to 95% electrical energy.It is proven that 5% DF is needed for occupants not to wantto switch on the artificial lighting.

CIBSE LG10IEA/OECD light’s labours lost


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F FWorked example of good practice daylight design

• The model is a typical open plan office.• The building is shallow plan with a 15m width.• The example evaluates changes in the design criteria and their relative affect.• The example assumes a glazing type that is analogous with the latest sealed triple

glazed windows which comply with the forthcoming upgrade to Part L of thebuilding regulations.


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F F

63.73.9271.1216.173.927

POINTS => 2%MIN/AVEMINMAXAVE

DAYLIGHT FACTOR SUMMARY

Room Dimensions 30x15mCeiling height 2.8mWindow head height 1.8m

81.000.311.6518.835.25



Room Dimensions 30x15mCeiling height 3.2mWindow head height 2.2m

Worked example: Variance in room height


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42.120.270.7513.732.83



Room Dimensions 30x 15mCeiling height 2.8mWindow height 1m

24.000.140.3023.102.10



Room Dimensions 30x30mCeiling height 2.8mWindow height 1.8m

Worked example : Variance of room depth


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F FWorked example: summary

• Model 1 indicates that a good level of savings could be achieved but artificial lighting would always be required forthe majority of the year.

• Model 2 would save in the order of 8153 kWh/yr which equates to 3441 kg of CO2/yr. This represents 80% of theartificial lighting load(based on artificial lighting load of 11w/m2 and 8hrs/day daylight)

• Model 3 indicates that a window area of around 30% for minimal daylight conditions to be useful in offsettingartificial lighting usage.

• Model 4 indicates that room depth/height ratio is key and a rule of thumb of 2:1 should be targeted in early designappraisals.

As electric lighting is normally a base cooling load consequential savings in cooling plant sizes maybe achievable.

42%0.270.7513.732.8328%4 DEEP PLAN

24%0.140.3023.102.1021%3 LOW WINDOWS

81%0.311.6518.835.2540%2 HIGH WINDOWS

64%0.291.2017.334.2137%1 TYPICAL

DF POINTS => 2%Uo MIN/AVEDFMINDF MAXDF

AVE% WALL AREA GLAZEDMODEL



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F FSupplementing natural light with artificial light


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F FSunlight and daylight products 1

Sun pipes Heliostats

Light guides Solar harvesting blinds


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F FSunlight and daylight products 2

Light shelves Solar hybrid Lighting

Solar Chandeliers Solar hybrid Lighting


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F F

Case studies

S&SE HavantCribbs Causeway RSC

Kunsthaus BregenzMuseum of High Art Atlanta

Case studies

SAR-H


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F FScottish & Southern Energy, Havant

Additional rooflights

Viewing Position forDaylight modelViewing Position forDaylight model


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F FScottish and Southern Energy Penner Rd


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F FCribbs Causeway RSC

This building utilised shading to allow enough daylight toenter this 2 storey shopping mall whilst restricting the needfor comfort cooling and allowing uplighting in the wintermonths to create a virtual ceiling.


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F FKunsthaus Bregenz

Peter Zumthor’s Art Gallery works not only as asuperb Daylight building but also uses groundsource cooling to be a true leader in green design.


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F FMuseum of High Art Atlanta

This building utilised solar bracelet design in thedesign of the roof to maximise skylight penetrationwhilst shading direct sunlight and ultra violetradiation


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F FSAR-H Hanger Options

Rooflights improve daylight distributionInto a viable alternative to artificial light

Hanger standard side windowsdesign


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F FConclusions

• Daylight is a renewable source it is carbon neutral.• Daylight can replace up to 80% of lighting energy

consumption during daytime hours.• Daylight design needs to be combined with intelligent

lighting control.• Increased regulation will limit lighting energy usage.

good daylight design will become essential.• The UK should incorporate minimum daylight

standards to access carbon savings.• Daylight improves health, wellbeing and attentiveness

of occupants• Lights on blinds down = bad design


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F FPeople like natural light


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F FContact details

David MooneyBSc ACIBSE MSLL Dip LtgRegional Associate, Communities

Parsons Brinckerhoff6 Devonshire Square, London EC2M 4YE, UK44-(0)20-7337-1700; mobile 44-(0)7917-556814;

fax 44-(0)[email protected]; www.pbworld.com/ea

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