An indirect substation is used when district heating network conditions, such as pressure and temperature, do not allow direct connection. When a substation is connected indirectly, a heat exchanger provides energy-efficient heat transfer. It also ensures that the primary network supply side and the secondary building installation side remain safely separated.
In this way, the building application works regardless of pressure or temperature variations in the district heating network (hydronic balancing) and is safe from pipe breaks or leaks.
Danfoss indirect substations are self-contained units that are generally wall-mounted. They can support single or multiple heating circuits, with or without domestic hot water production on the primary or secondary side.
These advanced solutions are also available with an electronic controller for weather compensation. This ensures easy and energy-efficient operation while simultaneously allowing central monitoring and energy consumption transparency.
Features and benefits
Advanced solutions available also with an electronic controller for weather compensation
Indirect substations with Micro Plate™ heat exchangers provide energy efficient heat transfer
District Heating Substations operating guide
Use this document for planning indirect heating / cooling, dhw production and other water based heating systems. Can be used for DSA; DPS; DSE; DSS; DSM; and DSC product types.
A substation for indirect heating has a heat exchanger separating the primary flow from the secondary flow. Indirect substations are recommended for PN16-networks and higher pressure classes. Substations in this category are normally supplied with connection pipes for a domestic hot water cylinder on the primary side for the fitted constructions, and on the secondary side for the welded constructions.
Indirect or direct heating and domestic hot water cylinder
Substations for indirect heating have a heat exchanger separating the primary flow from the secondary flow. Indirect substations are recommended for PN16 networks and higher pressure classes. Substations for direct heating have no heat exchanger separating the primary flow from the secondary flow and are recommended for maximum PN10 or PN6 networks. The domestic hot water is heated in a cylinder by the district heating water flow in a coil within the cylinder.
Tools and apps
Solar heating plant reduces CO2 emissions by 15,700 tonnes annually
The world’s largest solar heating plant in Silkeborg, Denmark harnesses energy to heat the homes and workplaces of 40,000 citizens. It supplies 18-20% of the annual heat consumption in the city of Silkeborg, Denmark, which has an ambitious target of CO2 neutrality in heat production by the year 2030.
Renovation of an apartment building with flat stations, Hamburg, Germany
Until 2014, the apartments in this multi-family building located in the Hamburg suburb of Bergedorf were heated using electrical water heaters and supplied with domestic hot water using electrical instantaneous water heaters. Now, after the renovation, a block heating station in the basement of the building provides heating distributed via flat stations installed in the stairwell and used for decentralized domestic hot water. Tenants were able to stay in their apartments throughout the renovation process.