O
TOMORROW
ver half the world’s seven billion
inhabitants live in cities, by the year
2050 the number will grow to almost
ten billion. In order to avoid a climatic
collapse in the metropolises, there
is no other alternative to energyefficient buildings. Glass façades,
which produce eco-electricity, provide
heat insulation and sun protection and
also automatically adapt to the light
conditions, help when it comes to climate protection.
by the façade on bright days. It is fed into the local
heating network or stored in geothermal probes.
In winter, when the bio reactor produces less heat
energy, the BIQ draws the required energy from
these storage facilities.
Smart glass the key to the urban energy turnaround.
Wilhelmsburg used to be a no-no for visitors to
Hamburg. The neighbourhood is regarded as dull and
short of attractions. But its image is changing: it has
now become the location of the “greenest house” in the
Hanseatic City. With its so-called bio-reactor façade, the
five-storey BIQ – the abbreviation stands for “House
with Bio Intelligent Quotient” – is a trailblazer for
sustainable buildings and construction.
Algae grow in between the glass panels on the façade
and produce bio mass and heat from the combination
of light and carbon dioxide. The heat is directly fed
to the 15 apartments for heating purposes via heat
exchangers, while the bio mass is skimmed off. It is
used to produce bio gas, which a fuel cell converts into
electricity and heat.
A control system distributes the energy and
simultaneously regulates the growth of the algae, by
always feeding it with the exact amount of carbon
dioxide (CO2) from the fuel cell it requires for the
photosynthesis process. Each year the organisms
produce 4,500 kilowatt hours of electricity – that is
sufficient for two households. In the demonstration
project the remaining electricity requirements are met
by the public grid. In contrast, surplus heat is produced
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The algae house could assume a pioneering role
for future construction projects. Cities are absolute
CO2 producers: in global terms they consume
75% of the primary energy used and cause 80% of
greenhouse gas emissions, a rising tendency coupled