shading may be the solar strategy with the most
immediate benefit because it can greatly reduce
air-conditioning needs — an issue even in far-north climates. The chiswick Park office complex in
London makes extensive use of shading systems.
In hot and humid climates, where most of the
world’s people live, shading can reduce both
the need for cooling equipment and the ener-
gy needed to run the equipment. even places
fairly far north get hot. In cloudy London, at 51
degrees north latitude, shading devices are used
to minimize the use of air-conditioning systems
(see photos above). Germany, at 51 degrees
north latitude, may be the developed country
with the most use of shading devices, a strategy
Germans use to avoid the environmental conse-
quences of air conditioning.
not only would shading benefit most people
in the world, but it also provides benefits when
solar radiation is most plentiful. Passive solar,
on the other hand, is needed by fewer people
on earth and is collected when solar radiation is
at its minimum. This point is not an argument
against passive solar but in favor of using all solar
strategies, and especially shading.
Who promotes the low-hanging solar strate-
gies? because orientation, color of roof and walls,
some shading strategies and so on are ideas that
cannot be sold for money, they tend not to be
promoted by the market. Instead, they must be
promoted by nonprofit organizations such as the
American Solar energy Society (ASeS).
new and “cool” ideas are usually more popular than tried-and-true ones. but new ideas typically can’t beat the time-tested ones, and more
often they complement rather than replace existing ideas. For example, Pv should be seen as
a complementary solar strategy rather one that
displaces the existing solar strategies.
This school in London uses dynamic awnings to maximize shading, daylighting and passive solar heating.
n ORBERt LEChnER
Figure 2: Some low-hanging-fruit strategies are free or can even save money by reducing the initial cost
of a building. For instance, in certain cases, rotating a building 90 degrees can reduce the energy
required for heating, cooling and lighting by up to 50 percent.
Countering “What You know
For Sure that Just ain’t So”
Some may believe that these solar-responsive
design strategies are well-known, understood
and have been thoroughly investigated. by
looking at what is being built, including Leed
buildings, it is clear that these strategies are
neither well-known nor understood. Further-
more, much more research and good informa-
tion is needed. For example, the International
energy code requires low-solar-gain glazing
in all windows, thus preventing passive solar
heating benefits. Also, as mark Twain said, “It
ain’t what you know that gets you into trouble.
It’s what you know for sure that just ain’t so.”
For example, fixed-south-facing overhangs are
widely promoted in the architectural literature
even though they perform poorly in climates
that require summer shade and winter sun. Sky-
lights are also widely promoted even though
they collect the most sun in the summer and
least sun in the winter, which is the exact oppo-
site of what is required. And the literature pro-
motes vertical fins on the east and west, even
though they don’t work well and are terrible
for daylighting.
