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DAYLIGHT AND ENERGY EFFICIENCY

ANOTHER ASSET OF DAYLIGHTING IS ITS POTENTIAL FOR MINIMISING THE ENERGY CONSUMPTION OF BUILDINGS. LIGHTING REPRESENTS ROUGHLY ONE QUARTER OF THE ANNUAL ENERGY DEMAND IN A TYPICAL RESIDENTIAL BUILDING AND THREE QUARTERS IN A TYPICAL OFFICE BUILDING (WITH STANDARD INSULATION AND NO ACTIVE COOLING SYSTEM). THE HEAT GENERATED BY LAMPS AND OTHER FIXTURES ALSO RAISES THERMAL LOADS. CONSIDERING THAT BUILDINGS ARE RESPONSIBLE FOR AROUND 47% OF CO₂ EMISSIONS WITHIN THE EUROPEAN UNION, ELECTRICAL LIGHTING HAS A DRASTIC IMPACT ON CLIMATE CHANGE.

THE ADVENT OF ELECTRICAL ENERGY AND THE DEVELOPMENT OF INDUSTRIALIZATION IN THE NINETEENTH AND TWENTIETH CENTURIES, PARTICULARLY THE VAST USE OF FLUORESCENT TUBE LAMPS IN DEEP PLAN OFFICES, BROUGHT ABOUT A TYPE OF BUILDINGS EXTREMELY DEPENDENT ON ARTIFICIAL LIGHT. TODAY, DUE TO THE INCREASING AWARENESS OF THE BENEFITS OF DAYLIGHT, THE TREND OF THE GOOD ARCHITECTURE IS TOWARDS A SYNERGY OF NATURAL AND ARTIFICIAL LIGHTING. THEY SHOULD COMPLEMENT EACH OTHER, AS CALDAS AND ROCHA (2001, P. 256) REMARK: “THE ARTIFICIAL LIGHTING SYSTEM IS SUPPOSED TO BE CONTINUOUSLY DIMMABLE AND TO PROVIDE JUST ENOUGH LIGHT TO MAKE UP FOR THE DIFFERENCE BETWEEN AVAILABLE DAYLIGHT AND DESIRED SET POINTS”.

IMPROVING DAYLIGHT DOES NOT MEAN INCREASING AS MUCH AS POSSIBLE ITS AMOUNT, MAXIMIZING THE SIZE AND PROPORTION OF GLAZING. TOGETHER WITH LIGHT, WINDOWS PROVIDE OTHER DESIRABLE ELEMENTS, LIKE SOLAR RADIATION CONTRIBUTING TO PASSIVE SOLAR DESIGN, VIEWS OUT, VENTILATION AND SOUNDS, BUT ALSO UNDESIRABLE ELEMENTS, LIKE EXCESSIVE HEAT GAINS OR HEAT LOSSES, GLARE, NOISE AND AIR POLLUTION, WHICH MUST BE CONTROLLED.

SUCCESSFUL DAYLIGHTING DESIGN MEANS ACHIEVING A BALANCE POINT BETWEEN SUCH STRENGTHS AND DRAWBACKS, THUS REDUCING THE ENERGY DEMAND OF NOT ONLY ELECTRICAL LIGHTING BUT ALSO MECHANICAL SYSTEMS FOR COOLING AND HEATING, TO PRODUCE A TRULY ENERGY EFFICIENT BUILDING WITH LOW ENVIRONMENTAL IMPACT.

ON THE WHOLE, ONE OF THE DESIGNERS’ CHALLENGES 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 and Christina Schulz (Basel: Birkhauser, 2006)

Caldas, Luisa and Joao Rocha, 'A Generative Design System 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 of Change, 2nd edn (Oxford: Architectural Press, 2001)

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DAYLIGHT AND AESTHETICS

FROM THE NARROW BEAMS OF LIGHT ILLUMINATING THE STATUES IN ANCIENT GREEK TEMPLES, THE DRAMATIC CONTRASTS OF LIGHT AND SHADOWS IN THE BAROQUE CHURCHES, TO THE INFUSION OF LIGHT IN THE RONCHAMP CHAPEL, DAYLIGHT HAS ALWAYS BEEN USED AS A FUNDAMENTAL ELEMENT OF ARCHITECTURE, ACTING AS PLASTIC COMPOSITIONAL MATERIAL. APART FROM SATISFYING OTHER HUMAN NEEDS, BUILDINGS SHOULD SATISFY EMOTIONAL NEEDS, AFFORDING SENSORIAL PLEASURE AND THE SKILFUL PLAY WITH LIGHT IS ONE OF THE MOST EFFECTIVE MEANS BY WHICH SUCH A PURPOSE CAN BE ACHIEVED.

THE ROLE OF DAYLIGHT TRANSCENDS THE FUNCTION OF ILLUMINATION. IT HAS ALSO BEEN A SYMBOL OF “CLEANLINESS, PURITY, KNOWLEDGE AND HEAVEN” (MOORE, 1985). RELIGIOUS BUILDINGS HAVE HISTORICALLY EMPLOYED LIGHT “TO AROUSE FEELINGS OF MYSTICISM AND TO CONVEY THE SACREDNESS OF A PLACE” (PLUMMER, 2009). 

MOREOVER, SHADOWS INTENSIFY THE EXPRESSIVENESS OF LIGHT AND THE PLAY OF BOTH CAN BE USED TO EMPHASISE THE COMPLEXITY OF THE SPATIAL COMPOSITION, ARTICULATING SPACES. IT CAN ALSO DEFINE SPACES, PUTTING IN RELIEF A PARTICULAR AREA OR REVEALING A PARTICULAR OBJECT.

PLUMMER (2009) MAKES A BRILLIANT ANALOGY SAYING THAT, FOR A MUSICIAN, THE VALUE OF A VIOLIN OR A PIANO LIES IN THE SOUNDS IT GENERATES AND SIMILARLY, FOR A VIRTUOSO ARCHITECT, A BUILDING IS AN INSTRUMENT WITH WHICH SUBLIME EFFECTS ARE CREATED OUT OF NATURAL LIGHT. 

REFERENCES  

Moore, Fuller, Concepts and Practice of Architectural Daylighting (New York: Van Nostrand Reinhold Company, 1985) 

Plummer, Henry, The Architecture of Natural Light (London: Thames & Hudson, 2009)

the importance of daylight 1

DAYLIGHT AND HEALTH

NATURAL LIGHT IS UNDOUBTEDLY MORE PLEASANT AND DESIRABLE THAN ARTIFICIAL LIGHT. THIS FIRST SECTION OF THE SERIES OF POSTS "THE IMPORTANCE OF DAYLIGHT" OUTLINES THE PHYSIOLOGICAL, PHYSICAL AND PSYCHOLOGICAL POSITIVE EFFECTS OF THE ADEQUATE AND COMFORTABLE USE OF DAYLIGHT IN ARCHITECTURE.

TO START WITH, THE CYCLICAL VARIETY OF LIGHT CONDITIONS (ALTERNATION OF DAY AND NIGHT) GIVES A SENSE OF TIME AND ORIENTATION TO HUMAN BEINGS, STIMULATING AND REGULATING THEIR BIORHYTHM AND HORMONAL DISTRIBUTION. FOR INSTANCE, THE ILLUMINATION LEVEL, THE EXTENT OF EXPOSURE AND THE SPECTRAL COMPOSITION OF THE LIGHT STRIKING THE RETINA, ALL OF WHICH CHANGE THROUGHOUT THE DAY, DETERMINE THE SECRETION OF MELATONIN (SLEEP HORMONE). ANOTHER BENEFIT FOR HUMAN PHYSIOLOGY IS THAT ULTRAVIOLET SUNLIGHT ACTIVATES THE SKIN’S PRODUCTION OF VITAMIN D.

EXPOSURE TO NATURAL LIGHT INCREASES HUMAN PHYSICAL ACTIVITY AND HENCE CONTRIBUTES TO IMPROVE PERFORMANCE, MOTIVATION AND PRODUCTIVITY, CRUCIAL IN WORK AND STUDY ENVIRONMENTS. BOTH POORLY LIT AND EXCESSIVELY LIT SPACES, ON THE OTHER HAND, LEAD TO FATIGUE OF THE EYES AND BRAIN, CAUSING FREQUENT ACCIDENTS AND ERRORS.

NOT ONLY THE AMOUNT OF LIGHT, BUT ALSO ITS QUALITY, AFFECTS VISUAL AND GENERAL PERFORMANCE, AND HERE LIES ONE OF THE GREATEST ADVANTAGES OF DAYLIGHT IN RELATION TO ELECTRICAL LIGHT. THE LATTER’S CONSTANCY AND UNIFORMITY CAN ALSO RESULT IN TIREDNESS AND LACK OF ATTENTION. IT IS VERY HARD TO REPRODUCE THE QUALITY OF DAYLIGHT WITH ARTIFICIAL SOURCES, MAINLY ITS WIDE SPECTRAL COMPOSITION AND VARYING COLOUR TEMPERATURES.

LAST BUT NOT LEAST, NATURAL LIGHT HAS THERAPEUTIC PROPERTIES, REDUCING STRESS AND FEAR. SPECIALLY IF ASSOCIATED WITH VIEWS OUT, ALLOWING PEOPLE TO KEEP IN TOUCH WITH NATURE AND THE CITYSCAPE, THE OPTIMIZED PROVISION OF DAYLIGHT INTO BUILDINGS IS A POWERFUL STRATEGY TO HELP HEALING PATIENTS IN HOSPITALS OR, IN GENERAL BUILDINGS, JUST MAINTAIN A HEALTHY PSYCHOLOGICAL STATE OF THE OCCUPANTS. 

THE IMPORTANCE OF SUNLIGHT FOR GENERAL WELL-BEING BECOMES EVIDENT WHERE PEOPLE ARE DEPRIVED OF IT. IN CONTRAST TO TROPICAL COUNTRIES, IN HIGHER LATITUDES APPROXIMATELY 70% OF THE POPULATION ARE AFFECTED BY MINOR DEPRESSIVE MOOD VARIATIONS AND AROUND 3% OF THE POPULATION SUFFER FROM SEASONAL AFFECTIVE DISORDER - SAD, A CHRONIC DEPRESSION, DURING WINTER. REGARDLESS OF THE LATITUDE, SPACES WITH INSUFFICIENT NATURAL LIGHT HAVE BROUGHT CONSEQUENCES FOR PUBLIC HEALTH: FOR EXAMPLE, LACK OF DAYLIGHT IS THE SECOND MAIN CAUSE OF SICK BUILDING SYNDROME - SBS.

REFERENCES

ANDER, GREGG D, DAYLIGHTING PERFORMANCE AND DESIGN (NEW YORK: VAN NOSTRAND REINHOLD, 1995)

   

AUGUSTESEN, CHRISTINA ET AL., LIGHTING DESIGN: PRINCIPLES, IMPLEMENTATION, CASE STUDIES, ED. BY NICOLA KOLLMANN AND CHRISTINA SCHULZ (BASEL: BIRKHAUSER, 2006) 

FURTHER READING

"DESIGNING FOR AUTISM: LIGHTING" IN ARCHDAILY.COM