I have already spoken about the impact LED’s have had in lighting and the considerable energy savings that have been realised through the so called “Ledification” of lighting. Dramatic energy savings have been achieved and we have seen projects where the overall consumption of energy has halved and, in some cases, more than halved.
There are obviously some challenges and amongst these are the wiring challenges with increased inrush currents, as well as Flicker and Glare. In certain applications EMC may also feature as a major challenge for the lower cost LED solutions.
Controls do provide some additional energy saving but it would be wrong to assume that this is the only benefit of control as clearly this isn’t the case.
Obviously the most efficient luminaire is one that is switched off and to that end depending on the occupancy of the space then significant savings can still be made. A study undertaken many years ago in a warehouse demonstrated that an area of the warehouse was only visited a handful of times per year and yet the whole building was lit to a fixed value. As such, significant savings were made through the introduction of a Passive Infrared sensor, but this was an exceptional project. In most applications additional savings in energy can only be achieved if there is daylight and periods when the space isn’t occupied.
In most applications the additional savings in energy are at the lower end of the scale and will make a nominal impact on the energy consumed if the lighting is well designed. The benefit in these applications if therefore focused more on the user and how controls can improve the lit environment and generally improve the efficiency of that individual.
Lighting a space to the correct level saves energy but also aids comfort and ensures the task can be carried out efficiently and safely. In addition, controls simplify the switching and management of the space and as such reduce cost by minimising infrastructure.
Straightaway we have benefits that equate to a value, firstly fine tuning the lighting to achieve the correct light level and colour to suit the task. We still have maintenance factors so we over light the space from day one and unless we factor in some level of control, we are wasting energy and possibly affecting the efficiency of the individual performing their task. We should also highlight the fact that as individuals our lighting needs vary depending on our age, gender and the time of day so a fixed lighting value is not appropriate to how we function as human beings.
Secondly, the reduction of infrastructure through the use of controls to switch and dim. A robust infrastructure provides a reduction in hardware, which can be significant but again this rather depends on the nature of the installation. It’s worth mentioning that wireless networks are seen as the ultimate technology to reduce infrastructure costs and this is partly true, but it all rather depends on the nature of the space, how it’s used and the cost per control point.
In reality most buildings will evolve to embrace wireless once we have an approved open wireless standard such as IEC 62386 Part 104. This wireless to DALI-2 gateway supports a number of wireless protocols so you have choice of platform (Bluetooth/ Thread etc.) The key here is that interoperability is ensured by the standard, so hardware is no longer a restriction to good lighting control.
Practically most systems will be a hybrid of wired and wireless as factors such as parasitic load and cost per node drives projects. The parasitic load argument is also one that works against wireless as devices continually polling and communicating will consume energy and if a building is unoccupied for a large period of time then energy is being wasted.
I have argued that the benefit of control will outweigh the losses and this is partly true but if you have a wireless to many or combination of technologies then you can optimise the system for all applications. Like everything in life no single technology provides the panacea that will solve all of the challenges.
Controls have evolved beyond simply controlling a light source and now with the use of technologies such as BACnet and open standards such as IEC 62386 you are able to take information from an intelligent DALI-2 sensor and track movement, occupancy, daylight and provide this information to software or building management systems that allow end users to manage their buildings in a smarter fashion.
Integration of technology is here and combining lighting with HVAC and Security is something that can be done today and with the right approach the level of integration will grow with your building but it all rather depends on the choices you make with regard to your base installation.
An open approach to connectivity is the way forward and then sharing that data over protocols such as BACnet ensures disparate devices can function as one and provide us with significant savings in the overall infrastructure of our buildings.
In summary, the benefits of controls are far beyond pure energy, this is a byproduct of a well-designed building and if we manage our spaces correctly, energy will be saved, occupancy efficiency will improve ( Hawthorne affect) and safety is ensured through tracking and emergency lighting testing and monitoring.
Stewart Langdown FSLL