Daylight A Gift of Nature

Transcription

1 Daylight A Gift of Nature Nick Baker University of Cambridge Daylight is a gift of Nature. As civilized man learns to use artificial light, which frees him from the total dependence on daylight, he also learns to appreciate the value of daylight and its special qualities Hopkinson 1966

2 Early man spent most of the daytime outdoors - buildings were for shelter and security. Windows were small or non-existent. Reconstruction of Iron-age house at West Stowe, Suffolk, UK

3 Many tasks which are now indoors were then done outdoors Fish gutting at Grimsby, 1893 Historical re-enactment of 16th C. house carpentry at Kentwell Hall

4 The word window originates from wind-eye and was more for ventilation than for daylight. Baytree Farmhouse, E Sussex mid 16th Century In some harsh climates, the association of daylight with unwanted solar gains results in no formal windows being provided Excavated cave dwelling in Tunisia

5 State-of-the-art glazing was reserved for churches and cathedrals. 16th century stained glass in Kings College Cambridge. A Flemish glazier, using French glass for an English King

6 Corbusier, a Modern Master of daylight. Ronchamp France (1954)

7 Indoor tasks Oxford lib Corpus Christi Library at Oxford 1604

8 Trinity Library Cambridge by Sir Christopher Wren 1673 A huge light-diffusing box above an area maximised for book shelving - a perfect technical solution.

9 The Industrialisation of glass manufacture cast glass crown glass cylindrical glass float glass A woodcut from the 17th century showing the pouring of plate glass onto wooden moulds

10 The love-affair with glass The architect s dream of transparency Tinted glass - the response to overglazing Office buildings from the 70s and 90s 20 th century technology allowed facades to be almost 100% glass

11 Indicative Luminous efficacies Lumens/Watt Candle 0.3 Argand oil 1 Incandescent gas 2 Tungsten 14 Fluorescent 60 White LED 100

12 The first great migration indoors began with the Industrial Revolution. Industry provided both the need and the means to move inside. The second migration was to move away from the window. Advertisement from 1960 for the all electric office. An improvement on the outdoor environment!

13 Energy end use in non-domestic buildings Comparable units: The proportion of lighting energy to the total was obscured by quoting delivered energy. Primary energy relates closely to CO 2 emission

14 Installed lighting power 7.3 W/m 2 DF varies from less than 4% to 30% from inner to outer workstations Daylight Factor nd DF floor 2nd Daylight floor Factor dist m Note: both rows of lighting are ON at time of photograph, but invisible due to low visible brightness luminaires. Squire Law Library, Cambridge

15 94% 73% Calculated saving 2 nd floor reading area by operation of photo sensitive switching ON/OFF control. Switching datum 150 lux Installed lighting power 7.3 W/m * 3285hrs*0.992kW = 2378 kwh 0.94 * 3285hrs*0.992kW = 3063 kwh total = 5441 kwh reduction 24 kwh/m 2 or 83% saving during daytime only Squire Library: potential daylight saving on 2 nd floor reading area

16 The huge variance of energy use in buildings Energy use in 92 UK offices

17 THE INTRINSIC VALUE OF DAYLIGHT The appalling conditions in crowded cities prompted urban planning regulations based on ensuring the availability of daylight and sunlight 19th Century London by Doré

18 LEICESTER WATERFRONT DEVELOPMENT: Sky View Factors used to test compliance with daylighting regulations in Sustainable Homes directive 0m SVF mapped from digital elevation data at different floor heights. Then by calculating Daylight Factor, glazing could be placed and dimensioned to comply with target

19 LEICESTER WATERFRONT DEVELOPMENT: Sky View Factors used to test compliance with daylighting regulations in Sustainable Homes directive 2m SVF mapped from digital elevation data at different floor heights. Then by calculating Daylight Factor, glazing could be placed and dimensioned to comply with target

20 LEICESTER WATERFRONT DEVELOPMENT: Sky View Factors used to test compliance with daylighting regulations in Sustainable Homes directive 5m SVF mapped from digital elevation data at different floor heights. Then by calculating Daylight Factor, glazing could be placed and dimensioned to comply with target

21 LEICESTER WATERFRONT DEVELOPMENT: Sky View Factors used to test compliance with daylighting regulations in Sustainable Homes directive 8m SVF mapped from digital elevation data at different floor heights. Then by calculating Daylight Factor, glazing could be placed and dimensioned to comply with target

22 LEICESTER WATERFRONT DEVELOPMENT: Sky View Factors used to test compliance with daylighting regulations in Sustainable Homes directive 11m SVF mapped from digital elevation data at different floor heights. Then by calculating Daylight Factor, glazing could be placed and dimensioned to comply with target

23 Daylight in schools Design for school window E R Robson School Architect to the Greater London Council in treatese on School Design It is well known that the rays of the sun. Are to a young child very much what they are to a flower E R Robson 1874 Capastrino, California Percentage effect Difference as % of District ave. improvement Reading Math Daylight min to max Openable windows 7 - Window area min to max Skylight type A Skylight type B Openable windows 8 7 Impact of Daylight on reading and maths performance Source: Heschong Mahone

24 Daylight in Hospitals St Mary s Low Energy Hospital, Isle of Wight 1992

25 Hospital healing study analgesic strength number of doses wall group tree group strong moderate weak Comparison of analgesic doses per patient for wall-view and tree-view patients R S Ulrich 46 patients between 2 and 5 days after surgery

26 Visual Comfort - comparative study of preferences by K Paparia Jesus College Library Cambridge Optimisation or opportunity? Darwin College Library Cambridge

27 Frank Loyd Wright house Falling Water REAL NATURE Roof garden at office block in Athens

28 VIRTUAL NATURE Reproducing images from nature Olaf Eliasson Weather Project Tate Modern Charles Bartlet The River

29 SYMBOLIC NATURE Forms inspired by nature but not necessarily having the same function Milwaukee Art Musem - Calatrava Fan vaulting at Kings College Chapel Cambridge

30 ARTIFICIAL NATURE Environmental variance that is arbitrary and does not attempt to mimic nature Variable colour LED ceiling installation City Council of Stevenage

31 Conclusions Daylight is probably the most wasted resource in building servicing. With good geometry and controls, huge amounts of CO 2 emission due to artificial lighting could be avoided. Although daylight is present in most buildings, the art and science of good daylight design is not commonly practiced as part of architecture. Daylight, and its source, are a powerful link with nature and the forces which formed us. The windows of the building, that facilitate this link, are of vital importance. Though daylight itself may have technical qualities, it is the whole package a window provides light, vision, sound, fresh air and smells, that together are more than the sum of the parts