Heat pumps

Turning wastewater into a reliable heat source for district heating

23. February 2023
Turning wastewater into a reliable heat source for district heating

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A 2.5 MW wastewater heat pump system for E.ON Denmark demonstrates how treated wastewater can be integrated as a stable heat source in district heating networks.

OUR IMPACT

A 2.5 MW wastewater heat pump system is being delivered for E.ON Denmark in Frederikssund, designed to recover energy from treated wastewater and supply it directly to the district heating network.

The project includes full system design and EPC delivery, covering heat pump units, heat exchangers, piping, filtration and integration into the existing infrastructure. The system is engineered to operate under real conditions where wastewater temperature and flow vary over time.

In operation, heat is extracted from treated wastewater before discharge and upgraded to district heating temperature. The system uses ammonia as refrigerant and is configured to achieve high heat output relative to electricity input while maintaining stable performance.

A key engineering aspect is the handling of fluctuating source conditions. The design ensures continuous operation even when wastewater temperatures drop, enabling predictable heat supply across seasons.

The solution is also prepared for flexibility. If required, the system can be adapted to alternative heat sources, supporting long-term resilience of the district heating setup.

WHY IT MATTERS

Wastewater offers a continuous and local heat source.
 Well-designed systems can turn it into reliable capacity — even under variable conditions.

 

This article was originally published under Aalborg CSP and has been editorially adapted for aalborg hc systems.

WHAT WE DID

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delivered worldwide

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ANY QUESTIONS?

FAQ

What does aalborg hc systems deliver?

aalborg hc systems designs and delivers integrated heating and cooling systems in new and existing networks.

This includes:

  • large-scale heat pumps
  • thermal energy storage (TES and PTES)
  • integration of multiple heat sources

The focus is on complete system solutions, not standalone technologies.

Can you integrate into existing district heating plants?

Yes. Most projects involve integration into existing infrastructure. aalborg hc systems connects new technologies to:

  • existing networks
  • boilers and CHP units
  • available heat sources

The result is a coordinated system upgrade, not a replacement of existing assets.

Do you act as EPC contractor?

Yes. aalborg hc systems delivers projects on an EPC basis.

This covers:

  • engineering and system design
  • procurement and supplier coordination
  • construction and commissioning

The responsibility remains with one party from concept to operation.

Which heat sources can you integrate?

aalborg hc systems integrates multiple heat sources within one system, including:

  • wastewater
  • geothermal energy
  • ambient air
  • industrial excess heat

Solutions are designed as source-agnostic systems, optimised for local conditions.

What do you need to get started?

A project can start with a limited set of data:

  • heat demand profile (load curve)
  • supply and return temperatures

Based on this, aalborg hc systems defines a first system concept and integration approach.