Multiple mechanical and electrical installations (referred to as technical installations in this chapter) come together in one room. These typically are HVAC, lighting, and blinds. Each technical installation is automated and operated optimally from its perspective. For Desigo room automation, coordination of the individual technical installations must be optimized while considering that the same type of installation may exist several times in one room.
Room featuring:
- HVAC zone (blue)
- Lighting zones (yellow)
- Shading/blinds zones (green)
HVAC zone
The room typically is considered 1 HVAC zone influenced via a common automation and control strategy regardless of number and type of installed HVAC plant components (e.g., radiator, chilled ceiling, fan coil unit).
Lighting zone
All lamps operated/automated together are grouped into a lighting zone regardless of number and type of the installed lamps. A room typically has one or several lighting zones.
Shading zone
All shading products (blinds) operated/automated together are grouped into a shading zone regardless of number and type of the installed shading products. A room typically has one or several shading zones.
Desigo room automation and room coordination
Application function structure
Specific functionality is set up for each zone of each technical installation: The application functions. For Desigo room automation, this is supplemented by a room-wide function coordination called room coordination.
Room coordination basically has two application functions:
- Cross-technical installation coordination to ensure smooth functional interplay of the various installations
- Centralized, room-wide access point to operate and monitor a room
Cross-technical installation coordination
The application functions of the individual technical installations contain functionality required for technical installation-specific control. Additional functionality assuming coordination with other technical installations is part of room coordination. As a result, project-specific Desigo room automation requests and changes can be carried out without changes to technical installation-specific application functions.
Examples for coordination functions are coordination of HVAC and shading functions and coordination of shading and lighting functions.
Centralized, room-wide access point
Room coordination offers a centralized, room-wide access point to operate and monitor a room. This allows users to enter common data for several technical installations only once and retrieve them as a group.
Examples:
- Predefinition of the room operating mode (across all technical installations)
- Predefinition of a scene for the entire room
- Queries for general occupancy
- Common alarm for system alarms
The room coordination default solution influences the following functions:
Room operating mode
Various sources influence and determine the room operating mode:
- Centralized commands from scheduler programs or manual intervention
- Local commands from presence detectors or scheduler program override
Room coordination offers a centralized, room-wide access point to operate and monitor a room operating mode. The individual technical installations separately acquire all relevant information.
Scene
Scenes are defined to command several or all technical installations in a room via one single command, e.g., brightness of a lighting zone, or blinds positions in each shading zone can be defined for each scene. Room coordination:
- Controls a scene as per the predefined values
- Changes the predefined values
Both are carried out by the room user.
Thermal room load analysis
Room coordination supports room temperature control via blinds control. The various HVAC data is analyzed to determine the thermal room load and the associated signal definition for blinds control:
- Load if energy must be supplied to the room via the blinds position
- Unload if no additional energy must be supplied to the room via the blinds position
Blinds control determines the optimal blinds position in dependence of room occupancy and solar position (thermal radiation and glare).
Green Leaf (RoomOptiControl)
Manual room user manipulations (e.g., manual lighting and shading commands, or manual changes to the room temperature setpoint) can result in inefficient energy operation. Each zone and each technical installation is checked for inefficient definitions to be pointed out to the room user. Room coordination then summarizes the results and visualizes them on the room operator unit. The room user can then reset all manual entries (which lead to inefficient plant operation) by one single pressure of a button.
Room common alarm
One common alarm is set up for each room to keep down the number of set up system alarms. To this end, room coordination acquires status information (normal/alarm) for each zone and each technical installation, and determines the room-wide alarm state as a common alarm.
HVAC room control
HVAC plants and their HVAC devices in the room influence the climate in closed rooms.
HVAC plants in rooms are used to:
- Maintain a temperature range suitable for building occupancy
- Control other control variables such as humidity and air quality
- Efficiently operate HVAC plants in the room
HVAC plants in the room are grouped into plant families, radiators (right), Fan coil units (center), VAV (left), differentiated by mechanical design and functioning:
The members of the related HVAC family differ only marginally:
HVAC supply chain requirements
HVAC plants in a room consume energy. The supply chains outside the room supply air, water, or electricity to the room. Linked existing energy sources and consumers are called supply chain. An air supply chain or a water supply chain thus is an HVAC system with a supply/consumer relationship to the HVAC plant in the room.
The supply equipment typically supplies more than one room, and the HVAC plant in the room often is a consumer of multiple supply chains.
HVAC control basically has the same objectives as the entire HVAC plant:
- Maintain the room temperature in the selected comfort range
- Adapt the room temperature range to room user needs
- Supply, extract, and recirculated air to satisfy air quality and comfort needs
- Adapt the air flows to room user needs
Energy saving requirements:
- Devices for sequential control of a heating and cooling sequence and thus:
- Preventing sequence overlap (simultaneous heating and cooling)
- Using the most efficient energy source
- Reducing the temperature as soon as comfort mode no longer is needed
- Reducing ventilation as soon as it is no longer needed
Coordination of the HVAC supply chain:
- Operation of supply chain equipment as per user demand
- Optimization of operating levels (temperature, pressure) of the supply plant
- Prevention of damages to HVAC equipment
HVAC control structure
An HVAC control application in the room is connected to the following:
- HVAC plant in the room via sensors and actuators
- Room coordination application
- Centralized coordination application for HVAC supply chain(s)
- Building operator via BAC workstations
- Building automation and control functions for scheduling
- Room user
The HVAC control application in the room consists of two parts:
- Application function for user requirements
- Application function for HVAC plant control
The HVAC plant control contains a control module (CFC) that implements the control functions associated with the HVAC device.
Control concepts
The physical room conditions are controlled by a combination of control methods (setpoints by operating mode).
Sequence control
Algorithms for room temperature sequence control operate the heating and cooling equipment within applicable limits. The algorithm for one single heating element is as follows (e.g., radiator):
Below is an illustration of the temperature control sequence for a more complex HVAC plant in the room. The charts show the segregation of heating and cooling control sequences and associated setpoints and sequencing of heat convection by fan air flow or associated switching stages.
Individual temperature sequence controllers are assigned to each heating and cooling element. They intercommunicate to achieve required sequencing.
Open-loop control
Additional interactions between HVAC devices implemented via open-loop control functions are required in an HVAC plant in the room. The open-loop control functions feature two basic interactions:
- Support: Heating coil and cooling coil require the fan to run on the stage/speed required for their operation.
- Lock: The electric heating coil is locked to ensure that it cannot be operated without air flow.
Open-loop control and sequence controller are used together to implement the above, typical control sequence.
The following image shows the connection between controller and actuating devices (this does not correspond to the actual program structure).
Operating modes
The HVAC plants in the room adapt to the room's comfort requirements, e.g., ventilation is:
Active while the room is occupied
Off, as soon as the room no longer is occupied
The following illustrations show sequence control for an HVAC plant in the room for operating modes Comfort and Economy. Sequence control acts on heating and cooling equipment and a multi-speed fan.
Control sequences in the Comfort operating mode:
Control sequences in the Economy operating mode:
The available operating modes determine both operation and basic control strategy in the automation and control system at three different levels:
- The room operating modes determine the operation of HVAC equipment in a room in terms of current use by the user. The room operating modes defined for the room are available in all HVAC control applications in the room.
- The HVAC plant operating modes determine the operation the HVAC plant in the room with regard to existing, physical plant processes. The HVAC plant operating modes are defined specifically for 1 HVAC plant in the room.
- The device operating modes determine the operation of the HVAC devices in a room by predefining their tasks and implementation method. The device operating modes are defined specifically for each individual HVAC device.
Plant and device operating modes of a plant with heating coil, cooling coil, and fan
Project-specific adaptations of both plant and device operating modes can be implemented by adapting the operating mode table.
Plant operating mode | Fan operating mode | Heating coil operating mode | Cooling coil operating mode |
|---|---|---|---|
Off | Off | Off | Off |
Comfort | Modulating | Modulating | Modulating |
PreComfort | Modulating | Modulating | Modulating |
Economy | Modulating | Two-position | Two-position |
Protection | Modulating | Two-position | Off |
Heat up | Modulating | Two-position | Off |
Cool down | Modulating | Off | Two-position |
In addition, setpoints and setpoint limits define room and device operating modes. They can vary depending on the selected HVAC plant operating mode. Four different setpoints are provided for heating and cooling in the room.
The HVAC control applications in the room dynamically enable and disable the setpoints to achieve the desired combination of energy-saving Economy and demand-based Comfort operating mode.
Command priorities
An HVAC control application simultaneously achieves several goals. Functions with different objects may conflict when they are implemented. In this case, the command priority determines which command value has priority in the priority array of the BACnet objects.
HVAC control applications in a room are programmed to accept commands at many different levels, including operating mode variable level. As a result, HVAC control applications control the controlled output objects at a priority commensurate with the active priority of the operating mode variable. The following figure shows how commands and priorities are passed in the application.
The BACnet objects in the system support 16 priority levels. The HVAC control applications apply these levels as follows:
Priority | Purpose assigned to the level | Use in HVAC library |
|---|---|---|
Emergency mode 1 | Manual commands related personal safety | None |
Emergency mode 2 | Automatic commands related to personal safety | Propagated response to Emergency mode commands |
Emergency mode 3 | Unassigned - additional level for commands related to personal safety | None |
Protection mode 4 | Manual commands to avoid damage to equipment | None |
Protection mode 5 | Automatic commands to avoid damage to equipment | Programmed response to equipment safety conditions |
Minimum On/Off 6 | Commands to avoid damage by short cycling equipment | None |
Manual operating 7 | Manual commands through switches on equipment | None |
Manual operating 8 | Manual commands through BAS workstation | None |
Automatic control 9 | Unassigned - commands for comfort and energy conservation | None |
Automatic control 10 | Unassigned - commands for comfort and energy conservation | None |
Automatic control 11 | Unassigned - commands for comfort and energy conservation | None |
Automatic control 12 | Unassigned - commands for comfort and energy conservation | None |
Manual operating 13 | Manual commands through room unit | Programmed response to inputs from occupants |
Automatic control 14 | Unassigned - commands for comfort and energy conservation | None |
Automatic control 15 | Typical automatic commands for comfort and energy conservation | Typical automatic commands |
Automatic control 16 | Unassigned - commands for comfort and energy conservation | None |
Adaptation to another HVAC plant
An HVAC control application comprises several different members of an HVAC room family. It contains application-specific components (CFC) matching existing HVAC devices in the room. Components no longer matching existing HVAC devices in the room are either added, removed, or replaced to control a slightly different HVAC plant with different HVAC devices.
Often, more must be done than merely adding or removing components (CFCs). If, an HVAC device, e.g., is to be added, the following must be added or removed:
- Information in the operating mode table
- Corresponding BACnet objects to operate the new device
Shading control
Products and requirements
Suitable façade products and intelligent control allow for optimum satisfaction of various requirements for shading.
Façade products and their control required to protect against environmental influences or to make use of the same are the primary issue:
- Shading to protect against glare
- Using daylight
- Using solar energy for heating
- Shading to protect against overheating
- Protection against rain
Other requirements may be:
- Intrusion protection
- Protection of privacy
Façade product control in addition must protect persons and equipment against the façade products themselves. Examples:
- Drive up blinds in case of fire to open an escape route
- Protect against collision (e.g., in the event of outward-opening doors)
Façade control protects the façade products and their functionality against environmental damages caused, e.g., by rain, wind, or frost.
The market knows many different façade products such as roller shutters, blinds, awnings, etc. to satisfy the various requirements. The different properties of the products are included in the respective control functions. The following figure shows a few typical façade products (from left to right):
- Horizontal blinds
- Roller shutter
- Vertical blinds
- Drop-arm awning
- Vertical awning
- Sliding-arm awning
Influences on blinds control
Blinds control requires much information on environmental influences and user interactions to be able to best satisfy requirements.
The blinds control can be influenced by, e.g.:
- Smoke, fire alarm
- Maintenance switch
- Wind, rain, humidity, temperature
- Intrusion alarm
- Date/Time
- Solar radiation
- Geographical position
- Horizon limitation
- Presence detector
- Local operator
- Saving and retrieving scenes
- Central operation (operation, scenes, override)
- Desigo CC
- Commissioning/Test
Blinds position on a building, room purpose, and allocation of rooms to an organizational unit determine the type of information acting on blinds control. Example:
- Wind speed monitoring acts on all blinds of a building or building wing
- Automatic shading acts on all blinds of façade or part of a facade
- A scheduler program acts on all rooms of a renter
- Local manual operation acts on all blinds of a room, or on a single blind
Color key:
- Gray: Complete building
- Blue: Façade or part of a facade
- Green: Rooms of a renter, e.g., one floor
- Orange, red: Local, manual operation
The functions are grouped into local and central functions depending on whether the function acts on one or multiple blinds in a room, or on an entire group of blinds, e.g., on all blinds of a facade.
Grouping by local and central functions for the examples from the figure above
| Local manual operation | Automatic shading | Wind speed monitoring | Scheduler program |
|---|---|---|---|---|
Central function | n/a | Determination of optimal shading position in dependence of sun position | Measuring of wind speed Monitoring of wind speed Commanding of wind protection position | Commanding of a position in dependence of daytime |
Local function | Commanding of manual position Positioning of blinds | Decision on which position is commanded automatically Positioning of blinds | Positioning of blinds | Positioning of blinds |
Control concept
The control concept is based on the following:
- Grouping into autonomous functions determining a set position for the blinds
- Priority assignment to individual functions
- Evaluation of all functions and decision in favor of specific blinds position based on priorities
Overview of autonomous functions to control blinds
Priorities depend on plant requirements. The table shows the typical priorities in ascending format.
Function | Description |
|---|---|
Automatic shading
| Automatic determination of optimum blinds position based on current room use, solar radiation, outdoor brightness, solar position, and HVAC status. In simple terms, this function prevents glare in occupied rooms and uses solar energy for heating in unoccupied rooms, or protects the building against undesired heat-up. |
Manual operation (room, central) | Manual operation allows users to themselves determine the blinds position via buttons. If manual operation overrides a lower-priority function, a scheduler program or local presence information will reactivate the function. |
Presence-based influence (room) | Locking of automatic operation upon entering a room, and activation of automatic operation upon leaving a room. The presence-based function generally acts on the same priority as manual operation. |
Scheduler program
| A scheduler program opens, closes blinds at specific times, or commands them to a specific shading position. Furthermore, automatic operation can be activated or deactivated via scheduler program. Another priority may need to be commanded depending on purpose. If, e.g., automatic operation should be activated at noon, manual operation must be overridden by allowing the scheduler program to act on the priority for manual operation. If the blinds are to be closed at night without allowing for manual operation, a higher priority must be commanded. |
Automatic shading at high priority | For example, to prevent overheating it may be necessary to use automatic shading at higher priority, which limits or prevents manual operation in certain situations. |
Manual operation at high priority (room, central) | Manual operation at high priority allows for positioning blinds and overriding low-priority functions. For example, local operation can be overridden during, e.g., a presentation. Or it can be ensured that neither automatic shading nor a scheduler will drive the blinds up or down at an undesired time. |
Product protection, local
| Risks impacting a blind only, e.g., protection against collision with a service door opening outward, are included in local product protection. |
Product protection, central
| Environmental influences impacting a group of blinds are included in the central functions for product protection. A common function in this category is protection of blinds against damage from strong winds. |
Maintenance position, central | For maintenance or cleaning, blinds are commanded or blocked to a specific position at high priority enabling staff to carry out all required work without risking injury due to moving blinds. |
Protection, central | Blinds can be moved/driven up to provide escape or access routes for emergency personnel in the event of a fire. |
A very simple control contains just one or two functions; a complex plant may use many or all available functions. In addition, the response of individual functions may require parameterization depending on the requirements. The following figure shows an example of a plant including all functions.
Lighting control
Products and requirements
Suitable lighting products and intelligent control allow for optimum satisfaction of various requirements.
Lighting products and their control are the primary means to create optimum lighting conditions for building users:
- Optimum workspace conditions (bright or darkened rooms)
- Optimum lecturing/teaching conditions (presentation)
- Comfort in living spaces
- Mood lighting in entertainment spaces (restaurants, bars, etc.)
Other requirements may be:
- Energy savings
- Lighting of objects, products
- Façade lighting
- Intrusion protection
Lighting products control in addition must ensure the safety of persons. Examples:
- Switching on lights in case of fire
- Escape route lighting
A multitude of different lamps exists to satisfy the various needs, such as:
- Incandescent light bulbs
- Halogen lamps
- Fluorescent tube lamps
- Compact fluorescent tube lamps
- Metal halide lamps
- LEDs
For comprehensive information on lighting products and their application, see the e-learning module Lighting basics (B_B01RA).
Influences on lighting control
Blinds control requires much information on external influences and user interactions to be able to best satisfy requirements. The following figure shows an overview of the influences that may be considered as part of lighting control.
Lighting product positioning in a building, room purpose, and allocation of rooms to an organizational unit determine the type of information acting on lamp control. Example:
- A fire alarm acts on the entire building
- A scheduler program acts on all rooms of a renter
- Local manual operation acts on all lighting of a room, or on individual lamps
Gray: Complete building
Green/yellow: Rooms of a renter, e.g., one floor
Orange: Local, manual operation
The functions are grouped into local and central functions depending on whether the function acts on one or multiple lamps in a room, or on an entire group of lamps, e.g., on all lamps of a renter.
Grouping by local and central functions for the examples from the figure above
| Local manual operation | Fir alarm | Scheduler program |
|---|---|---|---|
Central function | n/a | Fire alarm reception Commanding of On-command | Commanding of On/Off command in dependence of time |
Local function | Commanding of manual brightness Adapting lighting | Switching on lighting | Switch on/off lighting |
Control concept
The control concept is based on the following:
- Grouping into autonomous functions determining a command for lighting
- Priority assignment to individual functions
- Evaluation of all functions and decision on the state of lighting based on priorities
Autonomous functions to control lighting
Priorities depend on plant requirements. The table shows the typical priorities in ascending format.
Function | Description |
|---|---|
Automatic control | Automatic switch-on/switch-off based on brightness, constant lighting control. In simply terms, this function achieves optimum lighting conditions automatically in occupied rooms, and switches off lighting when rooms are unoccupied. |
Manual operation (room, central) | Manual operation allows users to themselves determine brightness via buttons. If manual operation overrides a lower-priority function, a scheduler program or local presence information will reactivate the function. |
Presence-based influence (room) | Automatic switch-on when dark upon entering a room, and automatic switch-off when leaving a room. The presence-based function generally acts on the same priority as manual operation. |
Scheduler program
| Lighting can be switched on/off at specific times using a scheduler program. Furthermore, automatic control can be activated or deactivated via scheduler program. Another priority may need to be commanded depending on purpose. If, e.g., automatic control should be activated at noon, manual operation must be overridden by allowing the scheduler program to act on the priority for manual operation. If lighting is to be switched off at night without allowing for manual operation, a higher priority must be commanded. |
Manual operation at high priority (room, central) | Manual operation at high priority allows for influencing lighting blinds and overriding low-priority functions. For example, this function allows for ensuring that neither motion detectors nor scheduler programs can switch on/off lighting at the wrong time during a lecture/presentation. |
Maintenance, central | For maintenance or cleaning, lighting is switched on/off at high priority enabling staff to carry out all required work without risk of injury or being interrupted. |
Protection, central | Lighting can be switched on in the event of a fire alarm to light escape routes or support emergency crew access. |
A very simple control contains just one or two functions, A complex plant may use many or all available functions. In addition, the response of individual functions may require parameterization depending on the requirements. The following figure shows an example of a plant including all functions.
