HVAC controller portfolio of Siemens – everything for energy-efficient HVAC control

Energy efficiency

Intelligent and integrated building and room automation can produce considerable energy savings without sacrificing comfort. The European Norm EN 15232 (“Energy performance of buildings – Impact of building automation“) subdivides building automation into four energy efficiency classes from A to D. Energy efficiency class A, for example, states that energy savings in office spaces can reach 30% in relation to the standard. Synco offers important prerequisites for ensuring compliance with energy efficiency class A.

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Demand-controlled ventilation

The fan and the air handling processes – heating, cooling, humidification and dehumidification – are the major energy users in ventilation and air conditioning plants. For this reason, the fan should be switched off when ever possible and operated only when there is demand for ventilation resulting from inadequate indoor comfort conditions, using the lowest possible fan speed.

Switching on and increase of the amount of outside air delivered to the space take place via demand-dependent control (by means of indoor air quality (IAQ) sensors for acquiring CO2/VOC), presence-dependent control (with the help of presence detectors) or resulting from the sustained mode function for controlled variables such as temperature, humidity, etc. The process runs until the required operating state is reached. Then, the plant is shut down again.

Heat recovery

Heat recovery equipment in ventilation systems can help save considerable amounts of energy. The heat recovery process is controlled in sequences. This means that, first, the maximum amount of heat is recovered and only then will the heating or cooling sequences be activated. In addition, the operating action of the heat recovery equipment is adapted on the basis of a comparison measurement of extract air and outside temperature. The efficiency of heat recovery is monitored to ensure that, in the event of a failure, the lack of supply by the heat recovery equipment will not be compensated for by the air heating or air cooling coil, which would lead to extra energy consumption. If the efficiency drops below a certain limit, a fault status message is delivered.

Night cooling

During the night when the rooms are not normally occupied, they are cooled down with cool outside air. Expensive generation of cooling energy during the day can thus be minimised. Night cooling is activated via a comparison measurement of outside and room temperature and remains in operation until the required switch-off temperature for the room is attained.

Optimisation of heating circuit control including optimum start / stop control

The objective of optimum start control is to reach the Comfort or Precomfort set point at the beginning of the scheduled occupancy period. For that purpose, the heating circuit is switched on a period of time before occupancy starts, depending on the outside temperature. If a room temperature sensor is installed, the controller also takes into consideration to the room temperature when calculating the forward shift. If no room temperature sensor is available, the optimisation functions make use of a room model, which calculates the required room temperature based on the outside temperature, the building time constant, and the rate of room temperature rise.

Optimum stop control switches the heating circuit off as early as possible to ensure that the room temperature will lie just below the Comfort or Precomfort setpoint when the change from Comfort or Precomfort to Economy mode is made. Optimum stop control can be provided only if a room temperature sensor is present.

Quick setback of heating circuit

When the room operating mode changes from Comfort or Precomfort to Economy or Protection, quick setback is activated, the heating circuit pump is switched off, and the mixing valve is closed. The heating circuit remains shut down until the required room temperature is reached. As a result, the pump’s number of operating hours are considerably reduced. The function is ended when the room temperature reaches the new setpoint, or when the room operating mode changes to Comfort or Precomfort.

Demand-based production of heating and cooling energy

A heating boiler or refrigeration machine should operate only when there is indeed a demand for heating or cooling energy. Based on the information received from the heating, cooling or domestic hot water (DHW) zones, the Synco™ controllers automatically exchange data via the KNX bus. Using this information from the zones, the controllers calculate the required setpoints and switch on the respective heating or cooling sources depending on the demand. This makes certain that aggregates or pumps do not constantly operate, thus minimising the number of operating hours.

Highlights at a glance

  • Energy savings thanks to intelligent building automation up to 30% compared with standard rooms

  • eu.bac-certified controllers ensure energy efficiency and generate up to 14% less energy consumption thanks to their high control accuracy

  • Comprehensive product range for all types of applications

  • Versatility and expandability for future use thanks a modular concept and backward-compatible communication

  • Straightforward operation and quick commissioning

  • Superior support and comprehensive documentation

  • Decades of experience and high quality standards