Thus, when analysing the sustainability of a
construction system we tend to start with what
energy can be saved in different aspects of
habitability where energy is needed and how the
building influences its use. And this saving can be
seen from different view points:
a) Saving on interior lighting
Most membranes used in tensile structures
(above all white ones) tend to be translucent or
even transparent, as in the case of ETFE. So, the
amount of sun light inside a building covered by
membranes can be such that artificial lighting
is completely unnecessary. Not only this, in the
case of translucent membranes, interior lighting
is diffused so that there is no direct radiation or
glare. This can prove to be a very important factor
for sporting activities.
b) Saving on interior heating
In the same way that the membrane allows light
to pass through it, so does most of the infrared
radiation, be it by direct transmission or by
interior emission of the energy, absorbed by the
membrane. This energy, which penetrates the
inside of a space covered by membranes can
help to reduce heating costs in cold but sunny
climates such as the Mediterranean winter. In
some cases where the space is only used during
the day (e.g. a sports centre) the whole heating
system can be substituted. It is true, however,
that some heating may be needed on cloudy days
to create a warmer atmosphere. The same thing
would happen at night given that the membrane
wouldn’t give off thermal inertia owing to its light
weight. In any case this should come from the
floors or walls.
c) Saving on interior cooling
As in the previous section it might seem that this
is impossible. How can refrigeration be saved
inside a structure that lets in solar energy?
Simply by stopping it getting in using glass
enclosures. In fact, membrane manufacturers
created commercial departments for architectonic
tensile elements years ago. It mainly meant
correcting mistakes that many architects and
promoters had made in buildings with glass
enclosures in hot or temperate climates
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ninguna radiación directa o deslumbramiento, lo
que puede llegara a ser un factor importante en
las actividades deportivas.
b) Ahorro en calefacción interior
De la misma forma en que la membrana permite
el paso de la luz, también permite el paso de gran
parte de radiación infrarroja. Sea por transmisión
directa o bien por emisión interior de la energía
absorbida por la membrana. Esta energía que
penetra al interior del espacio cubierto con
membranas puede ayudar a economizar en
gastos de calefacción en aquellos climas fríos
pero soleados, como el invierno mediterráneo.
En algunos caso de uso del espacio solamente
diurno, (como las instalaciones deportivas)
podremos incluso eliminar totalmente la
calefacción del espacio. Es cierto, sin embargo,
que los en los días nublados deberemos recurrir
a algún método de calefacción, si queremos un
cierto confort en el interior. Lo mismo sucedería
por la noche, ya que la membrana, al tener tan
poco peso no proporciona inercia térmica al
espacio interior. En cualquier caso la inercia la
deberían proporcionar el suelo o las paredes.
b) Ahorro en refrigeración interior
De acuerdo con el apartado anterior, podría parecer que este apartado es imposible. ¿Cómo podemos ahorrar refrigeración i