Optimisation example 3 Heating, ventilation, cooling
The technical systems for controlling room temperature and air quality consume the largest share of energy in a building. Accordingly, the largest savings can be made here. Incorrect operation can lead to an expensive waste of energy. Energy consumption can be greatly reduced by optimisation of a building with regard to the architecture, construction and installation engineering.
On a room level, ABB i-bus® KNX intelligent building control supports the user in optimisation of the energy consumption and provides information to the installation engineering or the building control engineering for optimisation of the setting parameters. A presence detector used for control of the room lighting can simultaneously switch the room thermostat to absent mode as soon as the room is unoccupied for an extended period. Heating or cooling energy can be conserved in this way.
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Practical experience has shown that the reduction of the room temperature by 1 °C can reduce the consumption of heating energy by 6 %. If the room temperature is reduced by 3 °C during absence, 18 % of the heating energy can be saved in a non-occupied room. As the temperature level typically reacts slowly, this form of control is only useful for prolonged absences.
Linking the control to a seasonal blind control provides further savings in energy, as described in the optimisation example for blind control (see pages 16 and 17).
Electrical control valves – such as Electromotor Valve Drives (ST/K) with direct KNX connection or Electrothermal Valve Drives (TSA/K), which are controlled noiselessly via Electronic Switch Actuators (ES/S) – are used as control elements for automatic adjustment of the room temperature to the required temperature level. To avoid unnecessary energy consumption during ventilation, the control valves are closed automatically as long as a window is opened. The position of the valves can be used for feedback purposes as an indication of heating or cooling requirement in the building. The relevant systems can set their output to suit the current requirements.
IS SOMEONE IN THE ROOM?
Constant lighting control
Automatic blind control with louvre adjustment dependent on the position of sun
Room temperature control
in occupancy mode
Switch off lighting
Automatic heating /
cooling for blind control
Room temperature control
in absence mode