DAYLIGHT AND ENERGY EFFICIENCYANOTHER ASSET OF DAYLIGHTING IS ITSPOTENTIAL FOR MINIMISING THE ENERGY CONSUMPTION OF BUILDINGS. LIGHTINGREPRESENTS ROUGHLY ONE QUARTER OF THE ANNUAL ENERGY DEMAND IN A TYPICALRESIDENTIAL BUILDING AND THREE QUARTERS IN A TYPICAL OFFICE BUILDING (WITHSTANDARD INSULATION AND NO ACTIVE COOLING SYSTEM). THE HEAT GENERATED BY LAMPS ANDOTHER FIXTURES ALSO RAISES THERMAL LOADS. CONSIDERING THAT BUILDINGS ARERESPONSIBLE FOR AROUND 47% OF CO2 EMISSIONS WITHIN THE EUROPEANUNION, ELECTRICAL LIGHTING HAS A DRASTIC IMPACT ON CLIMATECHANGE.THE ADVENT OF ELECTRICAL ENERGY AND THE DEVELOPMENTOF INDUSTRIALIZATION IN THE NINETEENTH AND TWENTIETH CENTURIES, PARTICULARLYTHE VAST USE OF FLUORESCENT TUBE LAMPS IN DEEP PLAN OFFICES, BROUGHT ABOUTA TYPE OF BUILDINGS EXTREMELY DEPENDENT ON ARTIFICIAL LIGHT. TODAY, DUE TO THEINCREASING AWARENESS OF THE BENEFITS OF DAYLIGHT, THE TREND OF THE GOODARCHITECTURE IS TOWARDS A SYNERGY OF NATURAL AND ARTIFICIAL LIGHTING. THEYSHOULD COMPLEMENT EACH OTHER, AS CALDAS AND ROCHA (2001, P. 256) REMARK: THEARTIFICIAL LIGHTING SYSTEM IS SUPPOSED TO BE CONTINUOUSLY DIMMABLE AND TOPROVIDE JUST ENOUGH LIGHT TO MAKE UP FOR THE DIFFERENCE BETWEEN AVAILABLEDAYLIGHT AND DESIRED SET POINTS. IMPROVING DAYLIGHT DOES NOT MEAN INCREASINGAS MUCH AS POSSIBLE ITS AMOUNT, MAXIMIZING THE SIZE AND PROPORTION OF GLAZING. TOGETHERWITH LIGHT, WINDOWS PROVIDE OTHER DESIRABLE ELEMENTS, LIKE SOLAR RADIATIONCONTRIBUTING TO PASSIVE SOLAR DESIGN, VIEWS OUT, VENTILATION AND SOUNDS, BUTALSO UNDESIRABLE ELEMENTS, LIKE EXCESSIVE HEAT GAINS OR HEAT LOSSES, GLARE,NOISE AND AIR POLLUTION, WHICH MUST BE CONTROLLED.SUCCESSFUL DAYLIGHTING DESIGN MEANSACHIEVING A BALANCE POINT BETWEEN SUCH STRENGTHS AND DRAWBACKS, THUS REDUCING THE ENERGY DEMAND OF NOT ONLY ELECTRICAL LIGHTINGBUT ALSO MECHANICAL SYSTEMS FOR COOLING AND HEATING, TO PRODUCE A TRULY ENERGYEFFICIENT BUILDING WITH LOW ENVIRONMENTAL IMPACT.ON THE WHOLE, ONE OF THE DESIGNERSCHALLENGES IS TO WORK WITH THE INTERDEPENDENCE OF THE EMOTIONAL, PHYSIOLOGICAL,FUNCTIONAL, AESTHETIC, ECONOMIC AND ENVIRONMENTAL ASPECTS OF DAYLIGHTING.REFERENCES Augustesen, Christina et al., Lighting Design:Principles, Implementation, Case studies, ed. by Nicola Kollmann andChristina Schulz (Basel: Birkhauser, 2006)Caldas, Luisa and Joao Rocha, 'A Generative DesignSystem Applied to Siza's School of Architecture at Oporto', Caadria, 3(2001) 253-264 <http://wwwfaculty.arch.usyd.edu.au/kcdc/journal/vol3/caadria/Caldas.pdf> [acessed 06 Nov 2009]Smith, Peter F., Architecture in a Climate ofChange, 2nd edn (Oxford: Architectural Press, 2001) Biblioteca Britanica: Londres, Reino Unido, 1997, por Colin St John WilsonBRITISH LIBRARY: LONDON, UNITED KINGDOM, 1997, BY COLIN ST JOHN WILSONBibliotheque Britannique: Londres, Royaume-Uni, 1997, par Colin St John Wilson NEAR ST.PANCRAS STATION (WHERE WE GET EUROSTAR TRAINS), THE BRITISH LIBRARY WORTHS TO BE VISITED NOT ONLY FOR ITS AMAZING COLLECTIONS, BUT ALSO FOR THE QUALITY OFITS ARCHITECTURE. THE PICTURES ABOVE SHOW THE TWO TYPES OF SKYLIGHTS COVERING ITS ATRIUM. COMPARED TOSIDELIGHTING, TOPLIGHTING INCREASES UNIFORMITY OF THE DISTRIBUTION OF LIGHT,BUT ALSO INCREASES SOLAR GAINS AND HEAT LOSSES DUE TO CONVECTION ANDCONDUCTION. CONSEQUENTLY, TOP FENESTRATION NEEDS TO BE EVEN MORE HIGHLYINSULATED THAN SIDE WINDOWS. DAYLIGHT AND HEALTH NATURALLIGHT IS UNDOUBTEDLY MORE PLEASANT AND DESIRABLE THAN ARTIFICIAL LIGHT. THISFIRST SECTION OF THE SERIES OF POSTS "THE IMPORTANCE OF DAYLIGHT"OUTLINES THE PHYSIOLOGICAL, PHYSICAL AND PSYCHOLOGICAL POSITIVE EFFECTS OF THEADEQUATE AND COMFORTABLE USE OF DAYLIGHT IN ARCHITECTURE.TOSTART WITH, THE CYCLICAL VARIETY OF LIGHT CONDITIONS (ALTERNATION OF DAY AND NIGHT)GIVES A SENSE OF TIME AND ORIENTATION TO HUMAN BEINGS, STIMULATING ANDREGULATING THEIR BIORHYTHM AND