Sewage Heat Recovery in Cologne Sewer Systems ......17th International EWA Symposium “Water,...

17th International EWA Symposium “Water, Energy and Resources: Innovative Options and Sustainable Solutions”

Munich, Germany, 6-7 May 2014

Sewage Heat Recovery

in Cologne Sewer Systems –

Experiences of a Sewerage Company

Dipl.-Ing. Michael Knippenberg

Cologne Sewerage Company

Planning and Construction Sewer Systems

1



2

Overview

» Demonstration projects

» Mapping heat resources

» Wastewater disposal in Cologne

» EU Project CELSIUS

» Lessons learned



3

» Combined Efficient Large-Scale Integrated

Urban Systems

EU project CELSIUS

http://www.celsiuscity.eu

Ph

oto

by Ild

ar S

ag

de

jev

» „ …will enable the capture and utilization of the

secondary energy that is generated within cities every

day and that is otherwise lost to the atmosphere”



4

CELSIUS partners

» Gothenburg, Sweden

» Cologne, Germany

» Genoa, Italy

» London, United Kingdom

» Rotterdam, Netherlands So

urc

e: c

om

mo

ns.w

ikim

ed

ia.o

rg

“ …CELSIUS demonstrates

and promotes integration of

smart district heating and

smart district cooling.” (www.celsiuscity.eu)



5

Examples of demonstrators

» “…a package of innovative state-of-the-art energy

efficient technologies, systems and practices.” (www.celsiuscity.eu)



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Wastewater disposal in Cologne

WWTP

WWTP

WWTP

WWTP

WWTP

» 94 % combined sewers

» 155 km2 drained area

» 5 treatment plants

» 1 million inhabitants

» 2,400 km sewers in total

» 153 pumping stations



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Wastewater temperature (yearly average)

10,0

12,0

14,0

16,0

18,0

20,0

22,0

24,0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan

Waste

wate

r te

mp

era

ture

[°C

]

Time

2011

2012

2013



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Mapping heat resources

min. flowrate 10 l/s

min. width 600 mm



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Mapping heat resources



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Project partners in Cologne

Photo by Andreas Tille



• Many types of

buildings

• Various kinds of usage

• Heat from various

fluids

• Heating and cooling

Phase 3:

Integration

• Further types of

buildings

• Various kinds of

usage

• Heat from sewage

• Heating and

possibly cooling

Phase 2:

Expansion

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Objective for CELSIUS in Cologne

time

sta

ges o

f d

evelo

pm

en

t

Source: derived from RheinEnergie 2012

• Homogenous

types and usage

of buildings

• Heat from sewage

• Heating

Phase 1:

Innovation

we are here now



12

Heat utilisation

Source: Advisory Guideline DWA-M 114E



13

» Monovalent system

Covers the whole heat output requirement

Has to be approx. 5-10 times bigger than a…

Bivalent plants: economic and safe

» …Bivalent system

Heat pump provides the base load

Gas boiler is installed for peak requirements



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First CELSIUS sites in Cologne (March 2014)

District of Wahn

Area: 21,650 m2

Heat pump: 200 kW

Gas boiler: 1,000 kW

District of Mülheim

Area: 12,800 m2

Heat pump: 150 kW

Gas boiler: 850 kW

District of Nippes

Area: 28,200 m2

Heat pump: 400 kW

Gas boiler: 2,100 kW

District of

Weidenpesch

Negotiation with the

Cologne fire department



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» Up to 38 percent

Expected savings of primary energy

for the first three locations in Cologne

» Corresponding CO2-reduction:

about 540 tonnes p.a. So

urc

e: c

om

mo

ns.w

ikim

ed

ia.o

rg



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Construction site (secondary school in Wahn)

Location of the

heat exchanger

Location of the

heat pump



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Inlet and return flow positioned in a manhole



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Construction site (near high school in Mülheim)



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Perfectly designed for dry weather flow



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Sewage out of a pumping station („off-line“)

Major pumping

station

Heat recovery

plant



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Lessons learned (I)

» A feasibility study is indispensable

» Designing a heat exchanger needs flow measurement

» Pipes of less than 800 mm can be considered

» Mapping heat resources enables spatial analysis

» Approval of the water authority takes time



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Lessons learned (II)

» Special requirements for sewer cleaning

» Sewer rehabilitation has always to be possible

» Use simple water as heat transfer medium

» Sharing of information accelerates planning

» For accident prevention a railing is recommended



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Thank you for your attention!

Source: Gemeinnützige Gesellschaft des Kölner Karnevals mbH

gas – heat -

exchanger

Sewage Heat Recovery in Cologne Sewer Systems ......17th International EWA Symposium “Water,...

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