All about... District heating and cooling networks

By ENGIE - 30 January 2023 - 15:36

Have you ever heard of these networks that heat and cool buildings in your district ? Some of them may even take advantage of river water ! But do you know how it works ? Here is the why and the how.


Heating networks produce and transport heat in the form of hot water or steam for heating or domestic water use (hot water). 
Cooling networks produce and distribute cooling energy through a chilled water network to cool buildings. Reflecting a perfect balance between industrial and operational performance, they integrate advanced digital technologies and solutions to manage the networks.
For example, the City of Paris' district cooling network, developed and operated by Fraîcheur de Paris, a subsidiary owned at 85% by ENGIE and the RATP, the historical metropolitan operator of Paris, cuts CO2 emissions by up to 50% compared to stand-alone installations.

District heating and cooling networks to promote energy sobriety

District heating and cooling networks play a major role in reducing greenhouse gases and in the transition to carbon neutrality. 
Heating and cooling networks offer several modes of production capable of promoting energy sobriety. That is particularly the case when the cooling network directly uses the coldness of a local water source to cool the water in its network (a method known as free-cooling), or when recovered energy is used by a heating network. Other processes exist, such as geothermal wells or fatal heat recovery from a cooling network located near a heating network. 


A key role in the circular economy

Based on the circular economy principle, district heating and cooling networks play a key role in integrating and pooling the resources of the various available energy sources. First and foremost, they use local energy by exploiting a variety of resources such as fatal heat, energy from the subsoil with geothermal power, local forest resources managed on a sustainable basis, heat co-generated by local methanisation units or solar power with solar thermal energy. These district heating and cooling networks significantly promote energy efficiency and sobriety.

Heat or cold can be produced from all energy sources that can be harnessed:

  • Free-cooling (air, rivers, lakes or sea)
  • Recovered heat (from industrial processes, household waste incineration, data centers, metro, wastewater, etc.)
  • Renewable energy sources (biomass, geothermal, solar thermal, wood energy, biogas, and green hydrogen)
  • Cogeneration - much more efficient - that produces highly efficient heat and electricity (or heat, cold and electricity for tri-generation, also known as combined cooling, heat and power (CCHP))
  • Conventional fossil sources (gas)