Bio-inspired Adaptive Building Skins - Biotechnologies and Biomimetics for Civil Engineering - page 125

5.3.2.4 Function: Whole Building
The last category in this overview concerns examples of bio-inspired envelopes
which involve not just the façade layer, but the whole building in three dimen-
sions. Heliotrop, as a member of the class of rotating buildings, is a widely known
and well-cited example in this group (Randl 2008 ). The building, located in
Freiburg and designed by Rolf Disch architects mimics the directional growth or
rotation in response to the sun in the same way as some plants species do (Spie-
gelhalter 2012 ). By choosing its orientation in a clever way, the building can
modulate view and privacy, take advantage of solar gains when needed, or protect
against overheating if there is an overheating risk.
The ''Earth, Wind & Fire'' building concept (Fig. 5.7 ) seeks analogy with the
natural renewable potential of geothermal, wind and solar energy (Bronsema
2013a ). In this climate-repsonsive, whole-building concept, the building skin plays
a key role in creating a comfortable indoor environment. The gist of the design
concept is in the thorough integration of building physics and HVAC functions,
with the aim of obviating the use fossil fuel for fans and cooling machines. ''Earth,
Wind & Fire'' consists of three main components for conditioning of ventilation
air and creating sufficient pressure differences: (i) a venturi-shaped roof for
enhancing the supply air flow potential for natural ventilation (Van Hooff et al.
2011 ), (ii) a gravity-actuated heat exchanging façade with mist spraying system for
evaporative cooling, named Climate Cascade and (iii) a solar chimney for har-
vesting solar energy and inducing a buoyancy-driven ventilation flow. When
integrated with appropriate thermal energy storage systems, a simulation study
shows that the ambition of net positive energy building operation is within reach
(Bronsema 2013a ).
5.4 Design Support Tools
Biomimicry as a discipline is growing in the field of construction and architecture.
As evidenced by the wide range of selected application examples presented in this
chapter, there is already a considerable number of bio-inspired adaptable facade
concepts making its way into practice. It is argued, however, that in many cases,
the label 'bio-inspiration' was attached to the building envelope design in a rather
ad-hoc and sometimes superficial way. Moreover, the bio-inspired premises on
which these design concepts are based are not always fully understood, or do not
always accurately reflect the biological principles. This mismatch is exemplified
by the case of the well-known Eastgate centre in Harare, Zimbabwe. The building
is said to be modeled after the climate-control features of termite mounds, but in
fact is based on a flawed interpretation of how the biological system actually works
(Turner and Soar 2008 ). Although not necessarily a bad thing in itself, this finding
can be thought of as exemplary for the gap in domain knowledge that exists
between building designers and biologists.