Specifying the right district heating substation makes commercial sense

For heating, district heating and domestic hot water applications.

Brand: Danfoss

Image: A modern, well-lit industrial space showing a complex network of pipes connected to a black district heating substation unit mounted on a wall.

From flat stations to site-specific substations, Danfoss offers you a comprehensive range from a single supplier.

This brochure provides a clear, practical overview of the full range of Danfoss station solutions. For specific details and system design, Danfoss' technical support team is available to assist.

Choosing the right heat distribution system for a building or network depends on three key criteria:

Technical connection specifications
Heat requirements of the building
Comfort preferences of the building's occupants

Balancing these needs accurately leads to better service for end-users and improved energy efficiency, benefiting your business.

Specifying your system

System size is determined by the potential demand for heating and hot water. The temperature and pressure of the primary heat supply dictate whether a station operates directly or indirectly.

Technical criteria of the district heating network also influence the choice of control and heat transfer components. Equipment selection is further affected by the number and type of heating circuits, and the specific requirements for domestic hot water (DHW).

Complete solutions from a single supplier

Danfoss offers complete solutions covering flat stations and district heating substations, ranging from 2 kW to over 4 MW. These substations can be directly or indirectly operated, supporting one or more heating circuits, with DHW heating specified as flow, storage tank, or anti-legionella systems.

Key System Types:

Direct heating systems
Indirect heating systems
Indirect heating site-specific systems

Direct heating

Heating systems with directly connected substations

For decentralized domestic hot water (DHW) production and heat distribution.

Modern buildings often integrate renewable energy sources and must comply with strict DHW hygiene regulations. Central heating systems, utilizing buffer tanks for multiple energy sources, are often more financially sensible than individual systems for multiple apartments or houses.

Domestic hot water is produced on demand, without storing:

Buildings with decentralized DHW production require fewer supply lines, ensuring hygienically safe drinking water. If the volume of water between the heater and taps is less than 3 liters, regular hygienic testing is not required.

Each building or apartment features a directly connected substation or flat station with integrated DHW production. Heating circuits (radiator, floor heating) are supplied with heated water from the central heat source.

Diagram: Illustrates a simplified home heating system with a central heat source connected to radiators and a DHW tap.

DHW Systems

Products: EvoFlat 4.0 W, Termix Novi, Termix One, Akva Lux II

Description: Instantaneous water heaters with efficient Micro Plate™ heat exchangers. Suitable for single-family houses, apartments, and small multi-family buildings. Features stainless steel pipes and heat exchanger. DHW control options include pressure and/or thermostatic controllers.

Direct flat stations with DHW

Products: EvoFlat 4.0 M, EvoFlat 4.0 F

Description: For decentralized heating and instantaneous DHW production using an efficient Micro Plate™ heat exchanger. Applicable for multi-family houses and apartment buildings. Features stainless steel pipes and heat exchanger.

Direct house and flat stations with DHW storage tank

Product: Termix BTD

Description: District heating substation for direct heating of apartment buildings or single-family houses. Uses a cylinder with thermostatic or electronic control for domestic hot water preparation.

Diagram: Shows a direct heating system where the heat source directly supplies heating circuits (radiators/floor heating) and produces DHW instantaneously via a heat exchanger.

Indirect heating

Indirect substations

For networks with low-to-medium supply temperature and buildings with small-to-medium capacity requirements.

An indirect substation is used when district heating network conditions (pressure, temperature) do not permit direct connection. A heat exchanger provides energy-efficient heat transfer and safely separates the primary network supply from the secondary building installation.

This setup ensures the building application operates independently of network variations (hydronic balancing) and is protected from pipe breaks or leaks.

Danfoss indirect substations are self-contained, typically wall-mounted units. They can support single or multiple heating circuits, with or without DHW production on the primary or secondary side.

Advanced solutions include electronic controllers for weather compensation, ensuring easy, energy-efficient operation, central monitoring, and energy consumption transparency.

Diagram: Illustrates an indirect heating system where heat from the district heating network is transferred via a heat exchanger in the substation to the building's heating and DHW circuits.

Indirectly connected substations for heating and DHW

Products: VX Solo II, VXi Solo II, VXe Solo, Akva Lux VX, Akva Lux VXi, Akva Lux VXe, DSA1 MINI, Termix VX, Termix VVX, DSA WALL, DSA HOME, Unistat 1016.

Description: Indirect substations with efficient Micro Plate™ heat exchangers and variable connection possibilities for one or several circuits. Applicable for single-family houses, semi-detached, terraced, and multi-family buildings. These substations are wall-mounted.

Modular or site-specific indirect substations

For all networks and for buildings with medium-to-high capacity requirements.

District heating and cooling networks vary in size, from micro-networks using biomass and renewables to large-scale systems utilizing waste heat from combined heat and power production, waste incineration, or industrial processes. Some systems may also be supplied with steam, subject to technical and safety regulations.

Danfoss' experience ensures solutions meet all applicable requirements, considering energy supplier criteria, operator/owner needs, safety, energy efficiency, installation, and ease of use.

Diagram: Shows a multi-story building with individual flat stations connected to a central indirect heating and DHW supply.

Suitability:

Universal use in larger buildings
Connection of three or more secondary circuits
Mixing loops
Primary connection for domestic hot water

Products: Termix Compact 28 VX, Termix Compact 28 VVX, DSP 1 MAXI, DSE, DSP MOD@, DSM (mixing loop), DSS (steam).

Note: 90% of technical connection conditions can be met by modular district heating stations.

Quality and reliability are built-in

Danfoss develops and produces key components for its heavy- and medium-duty substations, as well as light-duty flat stations, in-house.

Complete control of system performance

In-house manufacturing ensures optimized heat transfer and system control. Pressure, differential pressure, temperature, and flow are automatically controlled and integrated in nearly all Danfoss substations.

Self-acting controllers, electronic controllers, and motorized control valves provide maximum comfort and energy efficiency. JIP® ball valves and ultrasonic energy meters ensure reliable shut-off and accurate flow/energy consumption data. These components are also ready for integration with Leanheat® software or SCADA systems.

Image: A close-up of a Danfoss substation control panel with a person adjusting a setting.

Choosing the right heat exchanger

Heat exchangers are crucial for transferring thermal energy from the primary network to the building's heating system. Two common types are Brazed Plate Heat Exchangers (BPHEs) and Gasketed Plate Heat Exchangers (GPHEs).

Brazed Plate Heat Exchangers (BPHEs):

Compact, efficient, and maintenance-free.
Ideal for smaller substations or installations with space constraints.
Permanently sealed for leak-free operation and high thermal performance, especially for DHW and space heating.

Gasketed Plate Heat Exchangers (GPHEs):

Offer greater flexibility and serviceability.
Modular design allows easy maintenance, cleaning, and capacity adjustment.
Suitable for larger substations or systems with variable load conditions.
Provide high thermal efficiency with low approach temperatures.
Can be combined with temperature and flow control valves for optimal performance.

Both types ensure reliable, energy-efficient heat transfer while maintaining essential separation between the district heating water and the building's internal circuits for safety and performance.

Image: A red gasketed plate heat exchanger unit.

Leanheat® Monitor boosts network and building efficiency

Real-time monitoring of controllers is key to optimizing district energy systems and improving operational efficiency. Leanheat® Monitor connects devices within the system (substations, controllers, production units, meters, network measurements) and third-party sources (e.g., weather forecasts) into a secure system.

Use Leanheat® Monitor to reduce operation costs, improve efficiency, and manage operations while complying with GDPR and other regulations.

It can be paired with Leanheat® Network, Danfoss' thermo-hydraulic modeling tool, for planning, visualizing, and optimizing the entire district energy distribution system.

Remote system management

The Danfoss ECL Comfort 310 controller is purpose-designed for Danfoss substations, offering a simple way to control heating and hot water systems in one or several buildings. Management is possible via smartphone, Leanheat® Monitor, or the controller's intuitive interface.

Try it today - Go online and create your user account.

Image: A split image showing a person using a laptop displaying a network map, and another person using a smartphone with a similar interface.

Optimize your entire district energy system with Leanheat® Network

Creating a thermo-hydraulic model of your network enables planning, visualization, and optimization for improved sustainability. Leanheat® Network allows evaluation of "what-if" scenarios, such as adding new areas or sources, identifying bottlenecks, and calculating optimal pipe dimensions to simulate network changes before investment, saving costs and time.

Optimize temperatures and reduce electricity costs for pumps

Leanheat® Network can create a real-time digital twin of the network. This digital twin helps reduce annual supply temperature, heat losses, and production costs. It minimizes pump costs by automatically calculating optimal pump setpoints, ensuring sufficient differential pressure to all clients, and providing full transparency into hydraulic conditions (temperature, flow, pressure) across the network.

Learn more about Leanheat® Network

Image: A computer screen displaying a complex network model with color-coded data points, likely representing temperature or pressure.

Your overview