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WASTE TO ENERGY
Passive Heat from City Sewer
Used to Heat and Cool Museum
Through a cutting-edge heat exchange system, the Museum of Bavarian History
in Regensburg, Germany, efficiently heats and cools its building, showcasing a
promising solution for urban decarbonization and clean energy strategies.
Nathan Madding
S
ustainable design and renewable
energy are key to helping municipalities
reach ambitious decarbonization
goals, and resilient cities are
turning over every stone in the hunt for
innovative, clean energy technologies.
One newly tapped source of low-carbon
energy in large cities is the steady temperature
of the cities' own wastewater,
which can be used as a source of energy
for both heating and cooling.
A Shining Example of Advanced
Energy Efficiency
The city of Regensburg, Germany, has
aggressive climate protection goals to
reduce carbon emissions and increase
energy efficiency. The city heavily promotes
the use of renewable energy
sources and energy-efficient building
practices. The Museum of Bavarian History
is an example of this commitment,
showcasing the implementation of a
heat exchange system that uses the
passive heat from city wastewater as
a renewable energy source for building
heating and cooling.
Completed in 2018, the Museum of
Bavarian History is a symbol of Bavaria's
rich cultural heritage, and its construction
was a significant milestone in the
state's history. Located in the historic
city center of Regensburg, this project
presented unique challenges, including
space constraints, a tight construction
schedule that needed to culminate with
Bavaria's bicentennial constitution and
centennial statehood anniversary, and
energy-efficient goals that depended on
advanced energy innovations.
Wastewater Provides Clean Energy
The museum turned to a hidden and surprising
source of energy flowing beneath
the city streets: the sewer system. Municipal
wastewater typically maintains a
temperature of between 50F and 68F
(10C and 20C), even in the winter. This
stable temperature range makes wasteJanuary
2025 | POWER
water an excellent energy source for operating
a heat pump that can be used for
both heating and cooling.
To take advantage of the wastewater
heat, an inlet structure extracts 70 liters
per second of wastewater from the
sewer. The coarse solids are removed
from the wastewater and the screened
water is pumped to two HUBER RoWin
Heat Exchanger units. Here, facilitated
by heat pumps, the heat exchange process
enables either heating or cooling
of the museum building as per seasonal
requirements. The self-cleaning feature
of the heat exchangers ensures sustained
performance, further enhancing
operational reliability.
Due to the heat exchanger operation
in combination with the heat pump, heat
is either extracted from the wastewater
and introduced into the building (for heating)
or heat is extracted from the building
and introduced into the wastewater
(for cooling). The wastewater is finally
returned to the sewer together with the
previously separated solids. HUBER supplied
the self-cleaning ThermWin system
with a heat output of 560 kW and a cooling
capacity of 1,000 kW.
A Model for Sustainable
Development in Cities
The significance of ThermWin extends
beyond its application in the Museum of
Bavarian History. Recognizing its potential
as a future-oriented solution amidst energy
crises and climate change, Bavaria's
Minister of Finance and Home Affairs,
Albert Füracker, lauded the system as a
model for sustainable development (Figure
1). The success of this project paves
the way for broader adoption, inspiring
similar initiatives globally. In Toronto,
Canada, for example, HUBER supplied 16
RoWin wastewater heat exchangers (size
8) in 2023 for what was at the time the
largest project of its kind in the world.
" In Bavaria, tradition and innovation
go hand in hand. This is impressively
demonstrated in the House of Bavarian
www.powermag.com
1. Pictured here in front of the Museum of
Bavarian History's two HUBER RoWin Heat
Exchanger units are Museum Director Dr.
Richard Loibl, Bavaria's Minister of Finance
and Home Affairs Albert Füracker, Regensburg
Mayor Gertrud Maltz-Schwarzfischer, HUBER
SE CEO Georg Huber, and HUBER Industrial
Sector Manager Wolfgang Schnabl. Courtesy:
HUBER Technology Inc.
History. The HUBER ThermWin system
installed in the state-of-the-art building
does justice to this idea of progress: It
uses wastewater for heating and cooling
and is a future-oriented showcase
model in times of energy crisis and climate
change. It is impressive to see that
what once seemed like a dream of the
future is now technically feasible. I hope
for many others to follow suit and be inspired
by this example, " Bavaria's Minister
of Finance and Home Affairs Albert
Füracker said.
The integration of HUBER's ThermWin
technology in the Museum of Bavarian
History exemplifies a paradigm shift in
building operations toward sustainability
and decarbonization. By harnessing the
latent energy in wastewater, this innovative
solution reduces environmental
impact and sets a precedent for futurecentric
infrastructure development. As
architects, engineers, and building owners
seek decarbonization solutions, HUBER's
ThermWin emerges as a beacon
of sustainable progress, bridging tradition
with innovation in the pursuit of a
greener future. ■
-Nathan Madding is director of
Green Building Solutions with
HUBER Technology Inc.
29
http://www.powermag.com
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