Direct heating systems

  • Overview
  • Product range
  • Documents
  • Tools and apps
  • Case studies

Conventional heating systems in single-family houses and apartment buildings consist of a central heat source and central DHW production. Today, renovated or new buildings are obliged to make at least partial use of renewable energy sources. All buildings must comply with strict DHW hygiene regulations.

In nearly all cases, it makes financial sense to heat multiple apartments, buildings or houses via a central system rather than individually. Modern central heating systems can use buffer tanks to combine different energy sources.

Buildings with decentralized DHW production need only three rather than the usual five supply lines to provide hygienically safe drinking water. If the volume of water held between the water heater and the taps is less than 3 liters, no regular hygienic testing is required.

Each building and apartment has a directly connected substation or flat station with integrated production of domestic hot water. Single or multiple heating circuits (e.g. radiator, floor heating system) are supplied with heated water from the central heat source.

Features and benefits

Domestic hot water is produced on demand, without storing

Heating systems can combine different energy sources

Product range

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    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.

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    Direct heating and domestic hot water

    Substations for direct heating have no heat exchanger separating the primary flow from the secondary flow. Therefore the supply from the network or the central oil-/gas boiler will flow directly into the network in each flat. Direct substations are recommended for maximum PN10 or PN6 networks.

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    Direct heating with mixing loop and domestic hot water

    Substations for direct heating have no heat exchanger separating the primary flow from the secondary flow. Therefore the supply from the network or the central oil-/gas boiler will flow directly into the network in each flat. Direct substations are recommended for maximum PN10 or PN6 networks.

Documents

Documents
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Tools and apps

Case studies

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    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.

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    District energy as the heating and cooling solution in Teknopark Istanbul, Turkey

    Building: Office
    Application: Production of heating, cooling and domestic hot water
    Challenge: Design and construct customized district energy solutions for all buildings on the park
    Solution: Danfoss  designed and constructed 3 pre-assembled DSE substations containing control valves for the heating, cooling and domestic hot water, heat meters, self-acting controllers and electronic controllers connected to a central Building Management System. 

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    District heating compact stations in Mikado House, Orestaden, Denmark
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    Modernized district heating in a hospital, Belgrade, Serbia

    Building: Hospital
    Application: Heating + Domestic Hot Water production by district heating substations
    Challenge: Modernize old and inefficient heat and hot water system
    Solution: 58 fully equipped prefabricated substations

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    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.

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    Flat stations in apartment building in Hamburg, Germany

    Visitors to Hamburg’s Henriette-Herz-Ring who let their gaze drift upward will discover two shipping containers on the roof of the apartment building. They are the visible result of an innovative planning initiative to replace inefficient gas boilers with Danfoss flat stations. The highlight of this renovation: residents did not have to vacate their apartments.