Solar shading REHVA Guidebook 12 presentation at 12th Annual

Solar shading REHVA Guidebook 12 presentation at 12th Annual Engineers Association workshop Lisboa on Oct 25th

Originally prepared by Wouter Beck, Hunter Douglas, editor of the Guidebook Presented by Olli Seppänen Member of the Solar Shading Task Force

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Author affiliations • Wouter Beck, Hunter Douglas, NL • Dick Dolmans, ES-SO, Belgium • Gonzague Dutoo, Dickson Constant, France • Anders Hall, Somfy Nordic, Sweden • Olli Seppänen, Finland, (REHVA)

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Task force Solar Shading started 2008

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Table of Contents • • • • • • • • • • •

Terminology Solar radiation Effect of windows on indoor environment Window systems Energy effects of solar shading How to choose a shading solution Automating and integrating solar shading Existing buildings Double-skin facades Maintenance of solar shading systems Cases

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Solar radiation

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Solar radiation

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Solar angles Lisboa 39, Porto 41degrees N

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Solar irradiance on a façade (lat. 50 N, clear sky)

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Solar irradiance on a façade (lat. 50 N, clear sky)

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Solar irradiance on a façade (lat. 50 N, clear sky)

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Effect of windows on indoor environment

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Effect of windows on indoor environment • Thermal comfort • Visual comfort • Acoustic comfort • Indoor air quality • Daylighting • Impact of productivity

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Thermal comfort • Air temperature

• Radiant temperature • Operative temperature • Relation to office worker productivity Federation of European Heating, Ventilation and Air Conditioning Associations

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Visual comfort • Contact with the outdoors

• Absolute brightness • Luminance ratios

• Color rendition

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Effect of good visual comfort • 3.75% median productivity increase [CMU]

• 20 to 25% less health complaints [Hartkopf] • 15% reduced absenteeism [Thayer] • 10 to 25% better performance on test of mental function • 20 to 26% faster progress of students [Heshong]

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Too high difference in luminance

Photo Somfy

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Solar shading reduces the differences aceptable

Photo Somfy

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The economic impact of productivity

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Window systems

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Energy flows

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Glazing properties depend on the wave lenght • Thermal transmittance

U

[W/m2K]

• Light transmittance

Tv

[-]

• g-value

[-]

• T=transmittance, R=reflectance, A= absorbtance

Standard double galazing

Solar control glazing

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Indicative properties convection loads

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Cooling loads – no shading

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Cooling load – exterior shading

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Surface temperature interior window pane under peak load conditions – no shading

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Surface temperature interior window pane under peak load conditions – exterior shading

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Energy effects

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Energy effects of solar shading • • • •

Orientation dependent energy balance of an office for Stockholm Amsterdam Madrid

• • • •

Three glazing types Standard double glazing Low-e Solar control glazing

(U = 2.9 W/m2K) (U = 1.2 W/m2K) (U = 1.1 W/m2K)

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Standard office • • • • • • • • • •

dimension ventilation infiltration daylight dependent lighting max. internal load art. lighting internal loads people internal loads equipment thermostat cooling thermostat heating shading set point

3.6 x 5 x 3 m 1.5 dm3/m2s 0.1 ACH 500 lx 12 W/m2 10 W/m2 15 W/m2 25/30 ºC (8-18/otherwise) 21/15 ºC (8-18/otherwise) 200 W/m2

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Effect of solar shading on energy use, Madrid weather data

Green=primary energy, blue=heat removed from room, red=heating of room, yellow=elctricity for lighting

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Cooling load reduction by solar glazing and shading

Cooling load for a model office in Madrid, Spain (latitude 40 degrees north ) depending on window orientation. Solid lines represent cooling loads without shading and the broken lines with external venetian blind shading. Red lines represent clear double glazing (g=0.75), yellow low-e glazing (g=0.64) and blue solar control glazing (g=0.32).

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Reduction in primary energy use for heating, cooling and lighting through shading, Madrid

std. double low-e solar ctrl

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Cost benefit analysis of solar shading, Madrid weather

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Cases

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Trafalgar House, Croydon Rain Screen Cladding

Concrete Walls

Extract Duct

Anti-Glare Blinds Internally

Exposed Concrete Slab

Aerofoils

Automatic opening window

Automatic opening vent behind louvres

Radiators

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Supply Duct

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Appendices • EU standards concerning shutters and blinds • Specification example

• Matrix of responsibilities

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Reviewers • Prof. Jan Hensen, Eindhoven University of Technology, The Netherlands • Prof. Mat Santamouris, University of Athens, Greece

• Hervé Lamy, SNFPSA, Paris, France • Prof. Michael G Hutchins, Sonnergy Ltd, Abingdon, UK • Dr. Thanos Tzempelikos, Purdue University, West Lafayette, IN, USA

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Acknowledgements • Ellen Kohl (Warema), • Maaike Berckmoes (Scheldebouw-Permasteelisa), • Risto Kosonen (Halton), • Bernard Gilmont (European Aluminium Association), • Maija Virta (Halton),

• Prof. Dirk Saelens (Catholic University of Leuven, Belgium • Prof. Zoltan Magyar (University of Pécs, Hungary)

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