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hksaato@hksaato.fi

HK-Säätö

District heating hybrid connections: heat recovery alongside district heating

In a hybrid connection, a heat recovery unit — most often an exhaust air heat pump — is connected to the housing company's district heating equipment. The whole is controlled by a single automation system. District heating remains the main form of heating and the reserve for peak loads. Part of the purchased energy is replaced by heat that would otherwise be blown out through the roof. HK-Säätö implements the automation and control of the connection so that both heat sources work together and not against each other.

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Why automation decides whether a hybrid pays off

Heat recovery and district heating compete for the same heating demand. If they are controlled by separate controllers, the heat pump and the district heating control valve can work against each other: the pump produces heat that district heating would have produced more cheaply, or district heating tops up the heating at a moment when the pump would have had capacity.

When a single automation system has the data on both heat sources, the outdoor temperature and the price of energy, it chooses at every moment which one heats. That is the part HK-Säätö does.

What the delivery includes

  • A survey. The condition of the current heat distribution centre, ventilation and automation, and an estimate of the recoverable heat based on exhaust air volumes.
  • A connection plan. How the heat recovery unit is connected to the heating and domestic water networks and on what conditions district heating tops up.
  • Automation and control. A shared controller for both heat sources, measuring points in the supply water, the return water and the heat recovery temperatures, and control logic that selects the heat source according to price and output.
  • Additional measuring points. We add measuring points for heating, ventilation, water systems and electricity consumption so that the output and the saving of the hybrid can be verified in Kiinteistöpilvi.
  • Cooperation with the HVAC contractor. The heat recovery unit and the pipework are installed by an HVAC contractor; we are responsible for the automation, the control and the commissioning. We deliver the whole together with our partner network.

When a hybrid is worthwhile

  • The building has mechanical exhaust ventilation without heat recovery. The heat in the exhaust air is currently lost entirely.
  • The heat distribution centre is due for renewal, so heat recovery is worth designing into the same project.
  • The price of district heating has risen and the housing company does not want to change the form of heating altogether.
  • The housing company wants to reduce purchased energy but keep district heating as a backup system.

Who we serve

  • For a housing company board comparing the options for a heating renovation and wanting to know what the saving really is.

  • For a property manager putting together the HVAC contractor and the automation supplier for a project.

  • For an HVAC contractor who needs an automation partner for a hybrid project.

  • For a property owner comparing the options for a heating renovation across several buildings.

Frequently asked questions

How much does a hybrid save?

An exhaust air heat pump replaces a significant part of the district heating purchased in an apartment building with mechanical exhaust ventilation. The exact figure depends on the exhaust air volume, the temperatures of the heating network and how well the automation controls the heat sources. In the survey we calculate an estimate from the building's own figures.

Does the district heating contract have to be changed?

District heating stays, but the contracted water flow or contracted power can often be reduced when part of the load moves to heat recovery. We advise on what to report to the district heating company.

Can a hybrid be added later if HK-Säätö already provides the automation?

Yes. Control of the heat recovery and the measuring points are added to the current controller, and the control logic is updated. A new controller is usually not needed.

Who is responsible for the whole?

This is agreed project by project. The most common model is that the HVAC contractor is responsible for the devices and the pipework and HK-Säätö for the automation, the control and the commissioning, and the whole project is handed over together.

Contact us

In the survey we look at the exhaust air volumes and the condition of the heat distribution centre, and calculate an estimate from your building's own figures.

Request a survey Submit a work order

See also