Implementing the correct DALI Lighting Control Strategies for Smart Buildings can often mean the difference between an efficient and effective DALI lighting control system or one that fails.
These strategies are accumulative and not mutually exclusive. The more strategies which can be included the larger the energy and costs savings. However balance between work comfort and productivity and energy and costs savings will have the maximum positive impact.
Implementing too many DALI Lighting Control Strategies will increase energy and costs savings but will be detrimental to the occupants, reduce productivity and in some cases people have been known to try and defeat and disable systems. The net result will be negative.
Implementing too few DALI Lighting Control Strategies reduces the system’s ability to meet legislated building codes, the amount of energy saved and the comfort provided and extends the system payback periods to a stage where they are less financially viable.
Your goal when designing these systems is to find a balance whilst serving your client’s needs and adhering to the necessary standards.
DALI Lighting Control Strategies 1: Time Based Scheduling
If the assumption is that the lighting will remain on 24 hours unless controlled, then this is one of the most effective DALI Lighting Control Strategies which can be executed.
Of course in a real world today with energy awareness among employees and Smart Building’s systems, this assumption will not always hold true. Nonetheless, implementing simple chronological Time Based Scheduling strategies serves to save anywhere up to 50% of costs related to lighting energy.
Expanding on this base level of time base scheduling with sunrise sunset schedules, holidays and exception scheduling, this remains a key contributor to DALI Lighting Control Strategies for Smart Buildings.
This strategy depends on the lighting design greatly.
As the International Standard for Lighting Controls, DALI compliant drivers and ballasts (DALI control gear) allows a maximum level to be saved and recalled within the control gear itself.
This is a very simple, fast and effective way to save energy and reduce operating costs.
By setting the maximum output level below the maximum possible output, and thereby reducing the amount of energy required, a daily automatic energy savings can be realised. Of course if this top setting level is set too low to try and squeeze more energy savings, the required LUX may not be available to occupants which:
- May not meet building standards
- Could lead to poor productivity
- Possibly raise workplace safety concerns
This top setting strategy can also be achieved at a control system level, where the control system is instructed NEVER to call a 100% light output scene. One example may be where no user interfaces are programmed which allow a scene to be recalled which is equivalent to 100% output.
DALI Lighting Control Strategies 3: Day Lighting (a.k.a Daylight Harvesting)
This strategy requires use of sensors, in particular PE or Photo Electric cells, which can measure the level of reflected light in the space.
A typical open office application execution ensures PE sensors are mounted close to perimeter windows where most light ingress occurs. As the ambient reflected light levels increase and decrease the 2 rows of perimeter lighting are controlled up or down to maintain a predetermined LUX level in the space – typically on the work surface.
In a smaller, 1 person office application this Daylighting strategy can also inhibit the lighting from turning on at all if there is sufficient light in that office. Providing the ability for this to be overridden by the occupants as needed for task specific activity is recommended.
The energy savings contribution these DALI Lighting Control Strategies contribute to the overall energy savings of the Smart Building is challenging to determine in a broad sense and is better evaluated on a case by case basis.
One concern is contrast in-balances between the outdoors and indoors with this strategy.
Whilst it is common practice and ordinarily seen as more desirable to save energy with this strategy, making the inside potentially darker than outside effects an occupants connection with the environment outside.
This may have adverse effects on health and well being of the employees in extreme cases where the DALI Lighting control system may not have been commissioned correctly.
DALI Lighting Control Strategies 4: Occupancy/ Vacancy Control
Occupancy and vacancy control are 2 of the most effective DALI Lighting Control Strategies for saving energy.
Essentially these strategies provide light only when light is needed. When offices, meetings rooms or whole floors are not occupied there is no need to have light beyond the regulated requirements for safe egress. This equates to energy saved. Simple.
Occupancy strategies typically detect when someone enters a space – via a sensor technology – illuminates the space to a predetermined level, continues to monitor if the space is occupied, and when it no longer has occupants – and therefore light is not longer required – turns the lights either to a lower level or to off. Sometimes even both.
Vacancy control strategies typically require direct human interaction. Where a person enters a space and chooses to turn the lights on in that area. From that time on, the same sensor technologies search for occupancy and when none is detected activates an unoccupied lighting scene. This scene may have multiples levels or may switch the lights off.
DALI Lighting Control Strategies 5: Task Tuning
Having the ability to control ones lighting to match the task at hand has been shown in a number of studies since the early 1990’s, to improve employee productivity.
Its really common sense. When you have the ability to create and recreate the correct environment for the activity being undertaken increasing the output and the quality of the work done is achievable.
The opposite is also true and represents an opportunity cost to employers when considering overall strategies for increasing employee engagement.
DALI Lighting Control Strategies 6: Personalised Lighting Control
Leveraging the native functionality of a DALI Lighting Control System – individual address-ability and control-ability – makes Personalised Lighting Control strategies much simpler to implement.
Personalised Lighting Control means that each individual can potentially control the lighting in their work space to a level which is most comfortable to them. This ability provides the occupant a personally optimised work environment and has been shown to increase engagement, productivity and energy savings.
Using the mouse as an occupancy sensor, coupled with the observed trend of employees selecting lower light levels increases energy savings.
By utilising these 2 open and ubiquitous standards – Ethernet and DALI – providing control to individuals at their desks, office or flexible work spaces is streamlined.
These Six Smart DALI Lighting Control Strategies for Smart Buildings provide facility managers, occupants and developers a foundation for productive work places which are energy saving optimised.