upon which the world relied, the coal and oil, had a finite life and once
used were not replaceable. No doubt this would have been ignored apart
from the further factor of a greater understanding of the greenhouse
effect due to the release of carbon dioxide by the burning of those same
fossil fuels. Finally there was the destruction of the ozone layer and the
increasing danger of global warming.
For these reasons some nations took account of the need for an intense
look at alternative means of energy, by means of wind and wave, and the
use of hydroelectric power where this was possible.
This was all taking place at a time when the amount of energy in
buildings was increasing, by means of the greater introduction of air-
conditioning to a point when it was apparent that buildings had become
the greatest single form of atmospheric pollution. Whilst this was clearly
the prime mover in calling a pause to the rise in the use of energy in
buildings, the role of the historic advantages of daylight were not
insignificant, the human factors demanding a closer look.
The historic result of this was that buildings, analysed as the greatest
cause of the problem, came under intense scrutiny; the words ‘passive
building’ and ‘sustainable architecture’ became of greater importance.
People began to seek ways to reduce the use of energy in buildings, and
the prime suspect became the energy used for lighting.
Passive architecture, is where the structure of the building is designed
in such a manner as to reduce the need for mechanical controls of heat,
light and sound to a minimum: the term ‘Net Zero Energy Demand’ or a
situation where ‘the energy consumed equals the energy harvested.’
Daylight and sunlight are at the heart of this new philosophy; they arrive
every day in greater or lesser quantity, and provide power for lighting in
two ways. First they enter the building through openings as ‘light’ to the
interior spaces and second they impact with the exterior building surfaces,
and can be translated into energy by means of solar conversion.
What it does mean is that daylight must be at the centre of the
architect’s strategy by the orientation of the building, by the nature of the
apertures, indeed the whole structure of the building.
This brings us back to the question of the infill of the apertures, at the
building’s perimeter... this is no longer glass just to keep out the
weather, but a very sophisticated window element which may be
designed to restrict or harvest the exterior energy, by means of selected
coatings, photovoltaics, cavity fills and advanced blind systems and
controls. It is in such ways that the amount of energy used for lighting
can be substantially reduced, contributing towards the ideal suggested of
‘net zero energy demand’.
It is clear that daylighting is at the heart of the equation, requiring a
holistic approach to design, in which the human factors outlined above
can now be placed in the correct order of priority; it is no longer true (if it
ever was) that daylight is a luxury concerned with the view out of the
window, although the view out of the window is an essential part of the
role that daylight must play.
In David Lloyd Jones’s thoughtful book Architecture and the
Environment, he defines sustainability in architecture as
‘development that meets the needs of the present, and is at least as
valuable to future generations as the value of the environmental
exploitation that results... a sustainable building (in energy
terms) is one that over its life breaks even or is in credit in respect
of energy consumption.’History 7