What are district heating and cooling networks?
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 CLIMESPACE, a subsidiary of the ENGIE group, cuts CO2 emissions by up to 50% compared to stand-alone installations.
How does it work?
Video of a cooling system in action
Video of a heating system in action
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 the heating network uses biomass as a fuel. 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 ground and 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, 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)