ReportAir Magazine

Introducing our new ControlAir CA-L3 controller

Connecting the dots – Fusing physical and digital

Airvent engineers have been developing automation solutions for ventilation systems since 2007. Our first successful project took place in Sweden in 2010, where we delivered and commissioned 250 chilled beams with the first-generation ControlAir control unit and the associated monitoring system. Now the CA-L3 represents the third generation of ControlAir control units optimized for demand-controlled solutions, such as VAV (variable air volume) and chilled beams.

 

The primary function of the third-generation control unit in the Airvent CA-CB (ControlAir Chilled Beam) product package is to keep the room temperature at the predetermined value based on the connected room temperature sensors and water-side control valves. The Airvent CA-CB (ControlAir Chilled Beam) product package includes the CA-L3 control unit and sensors for control, and is mainly intended for demand-controlled capabilities of the locally or zone-controlled chilled beams.

What's new in the 3rd generation control unit

Plastic cover for the controller

The CA-L3's plastic housing can be positioned anywhere on the chilled beam or near it (depending on the installation characteristics) within a distance of one meter - eliminating issues with difficult to access electronics.

Preventive condensation protection

The CA-L3 controller is equipped with a preventive condensation guard, based on the room temperature and humidity sensors built into the chilled beam and the thermometer placed on the water circuit of the chilled beam. The dew point temperature of the room is constantly compared with the chilled water temperature, and if the chilled water temperature is close to the dew point, the immediate disabling of the cooling mode is followed by a condensation danger alarm (flashing blue LED and building supervision alarm).

Modbus RTU-connection

The communication between the CA-L3 and the sensors is performed through an internal BUS. The Modbus RTU connection allows the setpoints to be set via a BMS (building management system).

CA-L3 chilled beam controller

What are the components of demand-controlled regulation and how do they operate?


1

 CA-L3 controller

The control unit, together with its own 24VDC power supply, is housed in a plastic capsule that is connected to the sensors on the chilled beams. The housing can be placed freely on or near the chilled beam, depending on the installation characteristics (avoiding the ceiling service opening and other obstacles).

2/a Integrated temperature and humidity sensors, built into the front panel of the chilled beam

The CA-CB controller has room temperature and humidity sensors built into the perforated front panel of the chilled beam. The desired temperature can be set via a Modbus RTU-related BMS.

2/b Wall temperature and humidity sensor with setpoint adjuster

The Produal Proxima® RU-D-RH wall control unit has a built-in temperature and humidity sensor, as well as a setpoint adjuster and a digital display.

2/c Temperature and humidity sensor built into the front panel of the chilled beam with a simple wall setpoint adjuster

The CA-CB controller has room temperature and humidity sensors built into the perforated front panel of the chilled beam. The desired temperature can be controlled with the Produal Proxima® RU simple wall setpoint adjuster. Recommended for rooms where individual fine-tuning of the desired temperature value is required.

3 Pressure independent control valve for the water circuit

The CA-L3 controls the performance throught the water-side control valves, based on the temperature sensor and the pre-set temperature value. As a result of the Belimo® pressure-independent control valves, real-time cooling or heating capacity control can be achieved by properly pre-setting the minimum water flow required for efficient heat exchange.

4/a Integrated motion sensors

In addition to the room temperature and humidity sensor built into the perforated front panel of the chilled beam, an optional 360° angle-sensing motion sensor with downward motion can also be integrated to distinguish between presence and absence modes. This option is ideal for presence-based ventilation of small office spaces (with chilled beams installed).

4/b External motion sensor

For larger rooms, an additional Regin® IR24-P external motion sensor can also be connected to the CA-L3 for visibility of the entire space.

5 Open/close airflow control valve for chilled beams

DUO is an airflow control valve with a unique damper blade, equipped with an on/off actuator as standard. When receiving a signal from a CA-L3 controller, the damper blade either opens completely when the zone or room is occupied, or closes in absent mode. When closed, the valve – through the special nozzle perforations on the blade – is still able to ensure very accurate and easily calculated airflows (depending on the chosen perforation type: A=10%, B=15%, C=20%, D=25% of the designed airflow), while securing low noise levels.

6 Window opening sensor

To save energy, the CA-L3 control unit can also be connected to a window opening sensor, which is set to disable cooling, heating or fresh air supply, if a window is opened.

7 Lighting control

Based on the signal of the motion sensor, we can distinguish between presence and absence modes, thus providing presence-based lighting control.