SOLAR
There are two distinct aspects to the question of the relationship of
energy to the power of the sun. First there is the heat gain from the sun to
those surfaces of the building which are insolated, for the most part on
the south elevation but with some additions to east and west. This can be
a useful addition to the heating of the building in the winter, but on the
obverse side can produce overheating in the summer, which must be
dealt with.
This however is not a matter to be dealt with under the heading of
daylighting, it being more concerned with the heating and ventilation
equation.
The second aspect, is very much one of daylighting; that of the use of
the sun to generate power by means of solar panels or photovoltaics, this
is an aspect of the relationship of the sun to energy, and a growing
technology.
Despite the fact that we lack the climate to provide large quantities of
solar power (as for example in Israel, where solar panels generating
power are the rule on properties rather than the exception) the
conversion of the sun’s energy into useful power has been shown to be
effective.
The building industry has a long way to go before the technology
already available makes a substantial impact, but as the energy crisis
becomes closer the means will be found (seeLighting Modern Buildings,
Case Study No. 11. The Solar Office at Doxford International Business
Park). It has been shown that some 30 per cent of the energy required for
an office building can be provided by means of photovoltaic panels,
provided that the orientation and construction of the building has been
planned for it.
LEGISLATION
Up to the twenty-first century little effort had been made to limit the
amount of energy used for the lighting of buildings by legislation; but a
start was made by Part L of the Building Regulations of 1995, dealing with
the conservation of fuel and power; this was a start to limiting the
amount of energy used for lighting in buildings, and this coupled with
the increased efficacy of the lamps and light fittings available from the
lighting industry, had a material effect upon the energy demand.
In 2002, revisions to Part L made it a requirement to consider the need
for ‘energy efficient lighting’ more seriously, and architects should be
aware of the current regulations, which in themselves will no doubt be
further updated and modified, to increase the need for further energy
savings for the future.
The new Part L requires that ‘Reasonable provision shall be made for
the conservation of fuel and power in buildings other than dwellings, by
... installing in buildings artificial lighting systems which are designed
and constructed to use no more fuel and power than is reasonable in the
circumstances and making reasonable provision for controlling such
systems’. There is some flexibility for lighting designers to comply with
the regulations, and there is every reason for the spirit of the regulations
to be wholeheartedly adopted.
The regulations are divided into two parts, the first (Part L1) dealing
with dwellings, and the second (Part L2) with non-domestic buildings.
42 Daylighting: Natural Light in Architecture