Commercial lighting is one of the most energy-intensive operational processes and taking it for granted, especially when it comes to control – or rather lack of it – can dramatically increase a building’s operational costs. Despite the drive towards efficient light sources, failing to reinforce any investment with a suitable control network will still leave facilities managers financially worse for wear. Here ABB Elkay, outlines what needs to be done to truly tackle inefficient lighting.
Shining a light on the need for change
Many public sector buildings, such as schools, colleges and wider educational facilities, have tight maintenance budgets which limit the extent to which facilities managers keep on top of a building’s energy-draining systems. Whilst their hands are often forced into action by the impact of legislative updates such as Part L of the Building Regulations or the European Commission’s Energy-related Products Directive (ErP Directive), taking the plunge and investing in a mass system upgrade can ultimately lead to significant long-term savings on energy bills, which would soon cover the capital expenditure of new equipment.
Lighting is a prime example. Some educational facilities systems are in operation for as much as ten years between serious maintenance cycles, and with the Carbon Trust identifying that lighting accounts for as much as 25% of a school’s total energy consumption, an out-of-date system can contribute to a significant amount of unnecessarily high running costs. When put into the context of a ten-year period, the potential overspend is staggering.
Installing high-efficiency lamps or LEDs is often the first port of call when aiming to tackle a poorly-performing lighting system. However, doing so without upgrading the wider lighting control infrastructure only scratches the surface of potential energy savings that could be made. Many existing lighting systems operate using simple on/off switches. As such, lights are either operating at full or no power, and the only energy-saving measure in place is reliant on staff, or students, turning the lights off when they leave the classroom.
Greater control over energy-saving lighting isn’t as seemingly inaccessible as it once was. Technological innovations have become more widespread, driving down costs and increasing availability to end-users with limited maintenance and operational expenditure.
One innovation – which some schools may already be familiar with – is absence detection, which makes use of a Passive InfraRed (PIR) technology built into an energy management device. A PIR sensor is an electronic device that measures infrared light radiating from objects in its field of view, and it can be used in the construction of PIR-based motion detectors. It is activated when an infrared source with one temperature, such as a human, passes in front of an infrared source with another temperature, such as a wall.
Absence detectors are operated by a switch as normal but when the person leaves the room the electrical load is turned off after a pre-determined period of time. Upon returning the switch must be operated to reactivate the load. As such, there is no risk of the light either switching off when someone is in the room, or switching on if the room is empty.
One final benefit which is offered by some PIRs, such as those from Elkay, is the ability to monitor and adjust lux level. This facilitates the potential integration of both daylight and artificial light to ensure a classroom is optimally lit, yet uses no more energy than necessary. As already alluded to, lighting systems which do not use any form of sensor and rely on on/off switches have two settings: full light, or no light. There isn’t a dimming option, and in many cases lights are used without really having much of an impact as the classroom may already be nearly fully lit by natural daylight.
However, by setting a pre-determined time and then using a sensor to monitors a room’s lux level, facilities managers can further reduce the amount of energy consumed by the lighting system. If there isn't sufficient ambient light to meet the require lux level, a classroom’s LED luminaires can be alerted by the sensor, via DALI, to supplement daylight with artificial light in order to bring the room up to its required lux level. As such, not all of a lamp’s output may be required to further reduce the amount of energy consumed.
Ultimately, upgrading lighting systems will help facilities managers in the education sector significantly cut operational costs. The technology to facilitate such an upgrade is readily available yet its accessibility perhaps remains beyond the knowledge of some who might think it out of their budget. Educating the market on the benefits of technology such as PIR sensors is central to driving forward change within the sector. Whilst maintenance and operational budgets for many schools may not be on a par with private sector companies, grasping the mettle and making the upgrade to an efficient lighting system which includes both low-energy lamps as well as sensor-based control elements will offer a tangible and long-lasting return on investment in terms of reduced operational costs and lower carbon consumption.