Controlling temperature and ventilation with KNX for energy saving and high comfort

0-10 V control signal for fancoils with brushless motors and inverter board offer an efficient control and a noiseless fan operation.

Fancoil units are a very common and successful solution for room heating and cooling in functional buildings. In order to save energy and reduce the noise at working places there is a growing demand of units equipped with brushless electronic motors and inverter boards. This kind of devices needs to be controlled by actuators which generate a 0-10 V control signal in order to allow a continuous air flow. In this project KNX was chosen for its native interoperability and the availability of a new ekinex® solution for the 0-10V control of fancoil units made much easier the integration of heating, cooling and ventilation in the building automation overall concept.

The office building, whose project was focused on comfort and energy saving, was equipped with a building automation system based on KNX. It is located in the north west of Italy and has demanding heating and cooling requirements, due to the external temperatures ranging from –10°C in winter to over 35°C in summer. The HVAC solution includes the temperature regulation for the conveying fluids and the single-room air temperature control.

Right temperatures for conveying fluids

The production of hot and cold fluids occurs in the boiler room where a chiller and a boiler are installed; the correct temperature of the conveying fluid in winter is ensured by an ekinex® KNX mixing actuator. The device allows a climatic compensation based on the external air temperature; the value used by the mixing actuator is measured by a KNX weather station that sends on the bus also further information.

Single-room control

The control of the air temperature is achieved with the ekinex® fancoil actuators installed in the fancoil cabinets and ekinex® wall-mounted room temperature controllers. In some large rooms the setpoint value for the regulation is obtained as weighted average between the temperatures measured by the room temperature controller and the sensor integrated in an ekinex® KNX pushbutton used for the light switching. In service rooms, where no room temperature controllers are installed, the fancoil actuators work also as controllers, receiving the room temperature by a KNX temperature sensor. In this case setpoints and change of operating modes are received via KNX by the building supervision system.

Easy-to-use with the App

An ekinex® delégo supervision system allows users with iOS and Android smartphones to control individually room functions such as lighting and heating / cooling / ventilation with a simple and user-friendly App. 

Comfort and energy saving

The ekinex® KNX fancoil actuators / controllers offer several functions to save energy, obtain a higher comfort and make easier the maintenance. A temperature sensor measures the coil temperature and is connected to an input of the device, configured as analogic; in the heating season the fan start is delayed until the conveying fluid temperature at the coil reaches the configured threshold, in order to avoid an air flow at a discomfortable temperature toward the occupants. A window contact is connected to a second input, configured as digital, to switch automatically the operating mode each time a window is opened. In cooling mode a third input is used to detect the status of the floating sensor in the drip tray, starting the condensate pump when necessary. A dedicated counter triggers a warning when the configured threshold for the total operation hours is reached, informing about the need to clean or replace the air filter.

 

 

ekinex® KNX fancoil actuator / controller mounted on a fancoil unit. A 0-10 V signal is generated to control the brushless motor with inverter board.

 

 

The room control with the App delégo for mobile devices offers great user friendliness.