X-AIR-ZMO-MOD

Functional description

Zone modules are electronic control components for single room control. They control temperature, air quality and humidity, based on demand and based on occupancy.
A zone module controls the air terminal units for supply air and extract air, and a heating valve and a cooling valve.
A room control panel is used to operate a zone module.
A single room control system can be expanded by centralised functions if a zone master is used. One zone master module and up to 25 zone modules form a segment. Up to 5 cascading zone master modules form a section with up to 125 zone modules.

There are two ways to configure and operate the system:

• Using the zone master module
• Using the X-AIR-CP-2T room control panel with touchscreen

Volume flow control

The X-AIR-ZMO-MOD zone module activates up to 3 electronic air terminal units (2 for supply air, 1 for extract air) and provides the volume flow rate setpoint value. The actual volume flow control is handled by a volume flow controller.
The volume flow rate setpoint value depends on the operating mode, the number of air terminal units and the respective nominal volume flow rates. Parameters that are stored in the volume flow controller, e.g. q_Vmin and q_Vmax, are automatically read and evaluated by a zone module.
The operating mode default can be set either on the zone master module (i.e. centrally) or on the room control panel.
Operating modes

• Automatic mode
• Increased operation (q_Vmax)
• Reduced operation (q_Vmin)
• Shut-off
  
  

Operating modes set on the X-AIR-CP-2T control panel apply only for a defined period of time. After this period has elapsed, the zone returns to Automatic mode. Shut-off remains active until a user changes the operating mode again.
Damper blade positions and volume flow rate actual values of the air terminal units are signalled to the zone module and then forwarded to higher-level systems; the purpose is energy-efficient fan control.

Temperature control

A sensor measures the room temperature or extract air temperature, which is constantly compared to the setpoint value. In case of any deviation, the system controls airflows and/or water flows in such a way that the required room temperature is achieved (again). Variants:

• All-air system: Cooling is achieved by increasing the volume flow rate
• All-water system: Heating valve and cooling valve are actuated
• Air-water system: Variable volume flow, followed by valve control if necessary
• Air-water system: Valve control followed by variable volume flow control if necessary
  
  

It is also possible to combine room temperature control and supply air temperature control (cascade). With this type of control, the deviation from the room temperature is used to determine the supply air temperature setpoint. In addition, the supply air temperature is limited by a minimum value and a maximum value (can be configured).
Larger zones can be equipped with another 2 temperature sensors. The target value will then be the average value.

Air quality control

The air quality is measured with an air quality sensor (VOC or CO₂) placed in the room or in the extract air. If the measured contaminant content exceeds a certain value, the system keeps increasing the supply and extract air flows until the air quality improves. If a zone is fitted with heating or cooling valves, the system activates these valves in order to control the room temperature.

Humidity control

A sensor measures the relative humidity of the extract air; the value is then compared to a threshold value. If the relative humidity exceeds the threshold value, the system keeps increasing the supply and extract air flows in order to decrease the humidity in the room.
If a zone is fitted with heating or cooling valves, the system activates these valves in order to control the room temperature.

Window contact and frost protection

The zone module has a volt-free digital input for the connection of a window contact or a frost protection sensor. It is possible to connect a dew point sensor instead of a window contact. Users can choose how to use the digital input:

• Window contact:

The damper blades of the air terminal units, the heating valve and the cooling valve close.

• Dew point monitor

The cooling valve closes so that condensation is prevented. Volume flow control remains unaffected.

• Frost protection sensor

The heating valve opens fully to protect the heat exchangers. Volume flow control remains unaffected.

Motion detector

Another volt-free digital input is available for the connection of a motion detector (X-SENS-PIR-SM, X-SENS-PIR-FM). The volume flow rate is controlled as long as a room is occupied. If the room becomes unoccupied, volume flow control ends after a set switch-off delay, which can be configured.

Heating or cooling request

2 digital outputs on the zone module can signal a heating or cooling request and activate a heating or cooling system.

Operating modes

• Automatic: Demand-based zone control
  
  
• Minimum volume flow rate: All volume flow controllers are set to q_Vmin, temperature control and signalling to heating and cooling valves remain active
  
  
• Maximum volume flow rate: All volume flow controllers are set to q_Vmax, temperature control and signalling to heating and cooling valves remain active
  
  
• Fire alarm: Supply air q_Vmax or shut-off, extract air q_Vmax or shut-off
  
  
• Standby: All volume flow controllers are shut off, heating and cooling valves are closed

Application

Increasing requirements on the energy efficiency of ventilation and air conditioning systems as well as EU regulations can be fulfilled with intelligent control engineering solutions. 
X-AIRCONTROL is a control system that uses information from sensors and actuating elements to optimise ventilation and air conditioning systems. It calculates what all is required to achieve a comfortable room climate, and controls fans, pumps and valves accordingly.

X-AIRCONTROL is a modular system that can be used to optimise individual functions or a whole range of functions for a project.

• Evaluation of the damper blade positions of all air terminal units (not with zone module X-AIR-ZMO-ANA)
  
  
• Optimisation of fan speed control (optimiser function)
  
  
• Evaluation of the heating and cooling required for a zone
  
  
• Calculation of the supply air temperature setpoint value for the central air handling unit
  
  
• Configuration of the system, display of the system configuration, management of alarms – all from a central point
  
  
  

X-AIRCONTROL zone

An X-AIRCONTROL zone is an area where air conditioning parameters such as temperature and humidity are controlled based on demand and on the occupancy. These are usually individual rooms, but larger areas, e.g. open-plan offices, can also be divided into zones.

• Each zone is controlled by a zone module
  
  
• Sensors detect various air conditioning parameters as well as occupancy
  
  
• Actuators control these conditions
  
  
• Room occupants can use control panels to adapt the system to their own comfort requirements
  
  
• A zone module can be used either as a stand-alone unit or as part of a larger system

Stand-alone solution for a zone

A single zone module and a room control panel can be used to control a single room.

• Integration of air terminal units (maximum of 2 × supply air and 1 × extract air)
  
  
• Activate valves for cooling and heating
  
  
• Measure the temperature and configure the zone with the X-AIR-CP-2T control panel (required)
  
  
• Define schedules independent of the central BMS
  
  
• Simple wiring
  
  
• Plug and play connection of components
  
  

Use additional sensors (optional) to include other parameters.

• Occupancy
  
  
• Air quality
  
  
• Humidity

Interconnecting zones for multi-zone operation

Up to 25 zone modules and another 4 zone master modules can be connected to a zone master module so that a system of up to 125 zones is achieved. Different zone modules (Modbus, MP bus or Analogue) can be combined and connected with plug and play.

• Up to 25 zone modules per zone master module (segment)
  
  
• Up to 5 zone master modules (section)
  
  
• Up to 125 zone modules in a section
  
  

Each zone module controls and maintains the required conditions for the particular zone (single room) for which it is used. The zone modules are connected in series; 100 m cables (module to module) allow for linking even large areas or different buildings. Each zone master module and each zone module is automatically assigned a unique address (plug and play), which simplifies commissioning.

Advantages of a zone master module

• Central access for displaying and setting zone parameters with the integral web server
  
  
• Ethernet connection allows for easy integration with higher-level systems and for remote maintenance via the internet
  
  
• Option to connect a WiFi router (WLAN)

X-AIRCONTROL segment

A segment is a group of up to 25 zone modules; the entire segment is controlled as a unit, i.e. the same conditions apply to the entire segment. Grouping zones into segments is necessary when these zones are to be controlled centrally and when data from these zones are to be evaluated. A segment may be a floor in a building, the wing of a building or simply areas that are used differently from adjacent areas.

• A segment is controlled by a zone master module.
  
  
• Sensors detect various air conditioning parameters that are relevant to the segment, e.g. the outdoor air temperature
  
  
• Digital inputs and outputs are used to activate functions for a segment, e.g. to activate a fire alarm
  
  
• A web server (integral part of the zone master module) is used to configure the entire segment, to display the segment configuration, to monitor all segment functions and to manage alarms
  
  
• Modbus TCP and BACnet IP interfaces allow for integration with higher-level systems
  
  
• A segment can be run in stand-alone operation or it can be combined with other segments to form a section

X-AIRCONTROL section

A section is a group of up to 5 segments. A section may consist of up to 5 zone master modules and 125 zone modules.

• A section is controlled by the first zone master module
  
  
• If the first zone master module is connected to the control system of an air handling unit, the system can be operated most efficiently
  
  
• It is possible to have several, independent sections and hence create larger structures; there are virtually no limits to the size of the overall system

System solution with X-CUBE Compact

If a project is to include X-CUBE Compact air handling units, zone control with X-AIRCONTROL is the ideal system solution. With such a solution, the air handling unit's X-CUBE Control system not only activates fans, dampers and other components of the air handling unit, it also acts as the zone master.
The X-CUBE Compact air handling unit can serve up to 4 zones. If up to 4 zone modules are connected to the X-CUBE Compact, no additional zone master module is required.
X-CUBE Control includes an Ethernet interface and a web server for the configuration of the air handling unit, yet it can also be used to configure the connected zone modules.

• The zone master function is included in X-CUBE Control
  
  
• Up to 4 zone modules per X-CUBE Compact air handling unit, including variants (Modbus, MP bus or Analogue)
  
  
• Integral web server for configuring the air handling unit and the zone modules
  
  
• Remote maintenance is possible
  
  
• Expansion option: Up to 25 zone modules per air handling unit if an additional zone master module is used

System solution with X-CUBE

X-CUBE air handling unit can be optimised if one or several zone masters (integrated, multi-zone operation) are used. Using the following functions, a simple energy-efficient optimisation of the entire system is possible:

• Fan control based on damper blade positions of VAV terminal units
  
  
• Centralised air conditioning (heating/cooling) based on actual room temperatures and VAV terminal units

Design information

• Design and select sensors depending on the required zone functions
  
  
• Ensure that the zone module variants (Modbus, MP bus, Analogue) and actuators (volume flow controllers and valve actuators) you select are compatible
  
  
• For optimum energy efficiency, select zone modules with bus compatible actuators (Modbus, MP bus) as only these will signal information on valve and damper blade positions
  
  
• If you use an X-CUBE Compact air handling unit, you may connect up to 4 zone modules without the need for an additional zone master module