Solar-Powered Waste Management

An overflowing waste bin in
a park: pizza boxes piled up,
coffee cups, napkins and beer
cans on the ground. Cities all
over Europe have been fighting against
such a deluge of waste for years. Corona
exacerbates the problem because
people spend more time outdoors.
“With classic rubbish bins, waste
management in most cities is now
reaching its limits. Many metropolitan
areas in Finland, for example, had
to empty public waste bins up to four
times a day even before the pandemic,”
said Antti Kinnunen, marketing manager
at Finbin.
The Finnish company’s answer: a
waste bin called CitySolar, which compresses
waste and thereby has a much higher capacity. A waste bin that is
connected to the Internet and triggers
an emptying before reaching the maximum
fill level.
“With CitySolar, we are making a
contribution to reducing disagreeable
waste scenes in cities and improving
the CO2 balance in waste management.
Up to four out of five trips can
be avoided with the networked waste
bin,” Kinnunen added.

Less emptying: solar-powered
compactor compresses waste
Visually, CitySolar is reminiscent of
the robot R2-D2 from Star Wars—only
somewhat larger, more angular and
less noisy. Its operation is simple: a
passer-by opens the waste flap by hand or by foot. Once the flap has closed, an
electric press compresses the waste.
It is done so effectively that a container
with a capacity of 240 liters can
hold 1,500 liters of waste—with a total
weight of up to 600 kilograms. The
waste bin can do this work anywhere,
independent of the public power grid.
Because the engineers have installed
solar panels on the roof. In addition, a
lithium-ion battery that stores power
for cloudy periods and the night. This
means that energy is available for the
waste compactor around the clock.
Indoors, CitySolar is not dependent
on solar energy. The waste bin can be
connected to the conventional power
grid here.

Maintenance-free components 

To increase the sustainability of the
novel waste bins further, the engineers
have made every effort to use components
that do not require maintenance.
After all, every maintenance operation
causes CO2 emissions—solely through
travel to the site. Finding such components
was not always easy. An example:
the plain bearings for the mechanics of
the press and the skirting board. Classic
bearings made of metal were out
of the question for the job. Why? First,
because there would be a risk of corrosion
with high humidity. Second, because
the lubrication of metal bearings
can lead to several problems. It would
combine with dust and dirt and, over
time, become a paste that reduces the
bearing’s sliding ability, making the
system less smooth and, in the worst
case, leading to failure.
To avoid these problems, the engineers
set out to find lubrication-free
plain bearings made of high-performance
plastic. “We looked at bearings
from different manufacturers thoroughly,”
Kinnunen recalled. “Durability
and reliability were the main criteria
and the reason why we chose plain
bearings from igus.