What is a heat network?

In an era where sustainability and energy efficiency are increasingly in the spotlight, heating and cooling networks are crucial in delivering heat and cooling to neighborhoods, buildings, and industrial complexes. These networks represent an advanced system that transports heat and cold from central energy sources to end users, aiming to reduce energy waste and greenhouse gas emissions. By connecting these networks to sustainable sources, we can also avoid burning fossil fuels.

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What are heating networks and how do they work?

Heating networks are an innovative and sustainable solution for providing heat to homes, buildings, and even entire neighborhoods (known as district heating in this context). Instead of each building being heated by individual heating systems, heating networks use a centralized system to supply hot water to multiple buildings.

Heating networks can serve both B2B markets (like in France, where heat is delivered to the building entrance) and B2C markets (like in the Netherlands and Flanders, where heat is delivered to each individual home).

A heating network consists of a network of insulated pipes that transport hot water from a heat source, such as a combined heat and power (CHP) plant, biomass plant, waste incineration like IVBO, industrial waste heat, or geothermal energy, to end users. In the end-user buildings, this hot water is then used for heating, hot water for sanitary use, and sometimes even for cooling via heat pumps.

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Communal heating: mini heating networks within buildings

In addition to large-scale heating networks for entire neighborhoods or cities, there are also mini-heating networks within buildings, known as ‘communal heating.’ In communal heating, multiple apartments or spaces within a building are heated by a single central source in a boiler room. This boiler room contains a heat source, such as a boiler or a heat pump, that delivers hot water to radiators or underfloor heating systems in individual units.

Communal heating offers various advantages, including more efficient use of space and energy resources, lower maintenance costs, and reduced CO2 emissions. Additionally, it ensures even heat distribution and better control over energy consumption within the building.

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Generations of heating networks

Heating networks have evolved through various generations, each with its own characteristics and benefits:

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1. First generation: High-temperature networks (130-150°C) with steam, now less common.
2. Second generation: Medium-temperature networks (90-130°C) with hot water.
3. Third generation: Low-temperature networks (60-90°C) that are more efficient and better insulated.
4. Fourth generation: Ultra-low temperature networks (30-60°C), often linked to renewable energy sources. The Wonen in Limburg case study is a good example of this type of network.
5. Fifth generation: Bidirectional networks providing both heating and cooling with advanced storage methods.

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Seasonal Storage

Seasonal storage is crucial for optimizing heating networks. Heat can be stored in underground reservoirs in the summer and used in the winter, while cold can be stored in the winter and used in the summer. This increases efficiency and makes use of seasonal surpluses of renewable energy.

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Technical aspects of heating and cooling networks

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1. Central generation sources: Heating and cooling networks start at central generation sources where thermal energy is produced. This can be through various methods such as combined heat and power, biomass combustion, geothermal energy, or industrial waste heat.
2. Transport pipes: The core of the heating and cooling network consists of transport pipes. These pipes, made from materials such as steel or plastic, transport hot or cold water from the generation units to the end users. The pipes are carefully insulated to minimize heat loss or unwanted heating of the surroundings.
3. Control and distribution stations: Strategic points in the network house control and distribution stations. These stations regulate the flow and temperature of the thermal medium and distribute the heat or cold to different branches of the network.
4. Heat exchangers: In each building or apartment, a heat exchanger is used to transfer heat or cold from the network to the internal system without direct contact between the water streams. This prevents contamination and ensures efficient heat transfer.
5. End users: End users of heating and cooling networks are the recipients of the heat or cold from the pipes. These can be residents of houses or apartments, but also tertiary buildings like residential areas, commercial buildings, hospitals, industrial complexes, and other facilities. These buildings are connected to the network via heat exchangers, which transfer the heat or cold from the thermal medium to the internal heating or cooling system of the building.

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By combining efficiency, reliability, and environmental friendliness, heating and cooling networks contribute to a world where affordable, reliable, and sustainable energy is accessible to all. Technological advancements and increasing investments indicate a positive future, where these networks will provide more communities with sustainable energy.

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