Skylight The light received from the whole vault of the sky as modified
by the weather and time of day, ignoring sunlight.
Solar gain Heat derived from the sun; whilst generally therapeutic, it
may require control by forms of blind, louvre or solar glass.
Solar glass Glass designed to reflect a percentage of direct heat (infra
red) from the sun.
Solar panels Panels applied mostly to south facing fac ̧ades of buildings
designed to generate electricity from the sun. This can be used for heating
water or for lighting.
Solar shading The mechanical means by louvre, blind or special glaz-
ing, to eliminate glare from the sun. External means are the most efficient,
but can suffer from long term maintenance.
Sunlight The light received directly from the sun, as opposed to that
derived from the sky.
Sunpath The sun’s orbit. As the earth travels around the sun, variations
occur both throughout the day and the seasons; these changes in position
are known as the ‘Sunpath’. This can be accurately predicted.
Sustainability Applied to development which meets the needs of the
present, and is at least as valuable to future generations, as the value of
the environmental exploitation that results. This can be applied to the
concept of nett zero energy demand.
View The scene beyond a window which can be enjoyed from within a
space. The importance of this should not be underestimated.
Window ‘Wind-eyes’ take many forms, to provide daylight to an inter-
ior.
- LIGHT SOURCES OTHER THAN DAYLIGHT/
ARTIFICIAL
Arc light The first form of electric light derived by passing an electric
current between two electrodes. Developed by Sir Humphery Davy in
1809.
Candles Candles are made by moulding wax or other flammable mate-
rial around a wick, which sustains a flame to give light. Modern candles
are clean, do not ‘gutter’, and provide light of a particular quality suitable
for social occasions. There have been many light sources which attempt
to imitate the quality of ‘candle light’; most fail completely, while one or
two later versions achieve some success.
Electric light The development by Edison and Swan of the ‘incandes-
cent’ lamp in the nineteenth century and the arc lamp, providing the
foundation of all modern forms of light derived from electricity.
Electric light sources These lamps are described in detail in Chapter 5,
and are listed here.
Incandescent sources
tungsten filament
tungsten halogen
low voltage tungsten halogen
202 Daylighting: Natural Light in Architecture