We have for many years associated controls with a reduction in energy, but I want to expand this discussion to look at the other gains associated with a good lighting control system, especially when connected to a smart infra structure.
We have to understand that in the world of lighting and control, we are often only given the briefest of specification. This might be the light level and potentially the switching delays for the sensors. Meeting rooms will have pre-set scenes and where we have colour or Human centric lighting then cross fades and absolute values will be requested.
Often the use of the building may not be totally agreed and the desk locations or work spaces not clearly defined. In addition, we have to remember that as an industry we must consider maintenance factors and so by default we over light the space from day one. Obviously a correctly programmed multi sensor will regulate the connected load and dim accordingly thus saving the wasted light and energy.
There is a caveat here in that not all LED drivers respond in the same way and the lower cost option may have inefficiencies that only become apparent when dimmed. I have heard horror stories where a driver was dimmed by 20% to 80% of output and yet the power consumption rose. This is not a new phenomenon as many years ago mains filtering systems that were designed to reduce the onsite voltage and deliver saving came unstuck when the site had electronic ballasts. The ballasts were designed to compensate for voltage variation and therefore compensated for the voltage reduction. The net result was a very expensive system that saved zero energy.
It’s therefore critical that each component of an efficient lighting and control system is matched to the appropriate standards and that its characteristics are known and where ever possible certified as per the DiiA certification program.
I mentioned that we often don’t know the final use of the building if we don’t have an end client involved so must commission to a general value across the floor plate.
BS EN 12464-1:2011 Light and lighting. Lighting of work places, defines three key areas within a typical office denoted as the Task, Immediate surround and Background. The task as its name implies is the area where you need to focus and should be lit accordingly. The immediate surround is the area adjacent to the task area and can be lit at a lower value with the background being the area between desks/work spaces If we make the assumption that the background area is 60% of the floor plate then why should we light this area to the same level as the task?
Instantly a saving can be achieved by adjusting the lighting to focus on the task and not the background, however sometimes this can only be achieved once the building is occupied if desk location aren’t known at the time of commissioning. I would urge everyone to read up on BSRIA’s Soft Landings scheme which has a term called Post Occupancy Evaluation (POE) that provides a framework for this process.
We should also not forget that a degree of common sense must apply here as defined corridors should be maintained and correctly lit margins can improve the overall visual effect.
We are designing for the people that use or occupy that space and therefore improving the lit environment should be key.
Analytics are a key feature of connected lighting control and I will bring in the concept of the Internet of Things into this general discussion as there is a great deal of confusion on how best to integrate lighting into the world of IoT.
As an industry we have a defined standard for sensors based on the international standard IEC 62386 Parts103 & 104. This covers both wired and wireless input / output devices and provides a series of commands that are standardised across a number of manufacturers. In simple terms you ask a sensor a question and regardless of manufacture you get the same answer. Once you have that question answered then you can decide on a course of action and monitor the sensors and inputs to confirm the action or advise you of a change in circumstances.
The sensor can record how the space is used and for how long. It can provide data on a number of variables which can be reported back to a head end that provides a graphical overview of how the space is being used or in certain applications the number of individuals in that space.
Again, using the approach adopted by IEC 62386 this data can be published via the Application controller to another management software such as the BMS.
A DALI-2 sensor could therefore be considered an IoT device in its our right and if reporting to the BMS or Building management software then we have a connected device, or do we?
While the growth of wireless controls will certainly try and embrace this approach, we are perhaps losing sight of what a sensors prime function is and that is to switch and regulate lighting. As a subnet DALI does a great job in regulating lighting and an even better job of transmitting that data to a Cloud, be this a dedicated Lighting control Cloud or the clients IoT Cloud.
Resilience and Redundancy must be a prime feature of a smart system and I am concerned that attempting to define IoT as a component may undermine the functionality of the system as there is no defined set of rules for a grouping of components. Data is available today in a format that can be read by many different manufacturers and once Part 104 has been fully ratified then this information can be transmitted over a wireless protocol to more than one location.
At its core lighting control will always function in the event of a network failure as the connection to the Application controller ensures local command override. IoT is about data and although we can combine disparate systems to help fine tune and improve the functionality of the system, we should always maintain the integrity of the core system. This doesn’t detract from the connectivity as smart devices can connect locally and with the appropriate approvals tracking can record movement as well as the local temperature and other inputs. Smart devices such as mobile phones and wearables will play a part in this and if correctly configured will provide opportunities to improve the working experience. Booking meeting rooms can link to your diary and log you into the room once your phone or wearable device has located you in that room.
Air conditioning can be switched on or off and where appropriate presentation material be uploaded to the local device for your meeting. In managed spaces where meeting rooms are charged for then invoices raised, and emailed once the meeting has finished.
Safety can be improved by the use of IoT but only if the base system operates on known and approved protocols and it has been configured with Resilience and Redundancy in mind.
Being smart can provide significant energy savings with claims that some areas can see savings of up to 70% if they are not frequently used. Better planning will result in better use of space and could have a dramatic impact on the business by reducing their overall floorspace.
Simply empowering individuals within their own work space through local controls via mobile phone or by making them aware of the energy being saved, has a real positive benefit. Information is key and affects such as the Hawthorn effect show that sharing data and involving your staff in the operation of their building can deliver greater savings through an increase in productivity.
Efficiencies through technology are not always obvious and because we can do something doesn’t always imply that we should. The term IoT has many levels of integration and it’s critical that we balance the savings again the cost of ownership. I am a huge fan of cutting-edge technology and for me it’s get the infrastructure right and then add the technology in the areas where you will get the most benefit.
Stewart B Langdown FSLL
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