LIGHTING & CONTROLS


TAKE CONTROL OF LIGHTING ENERGY COSTS When it comes to reducing


the running costs of lighting systems, the utilisation of DALI brings effective


control, as Paul Drosihn, general manager of the DALI Alliance, explains


that operates around the clock. Alongside standardised commands for


F


or many looking to curtail the energy costs associated with lighting, typical strategies


include installing dimmers and timers, or simply remembering to switch off the lights at the end of the day. In reality, however, there is a far more effective way of achieving savings: automated lighting control.


STANDARDISED PERFORMANCE DALI (Digital Addressable Lighting Interface) is an open protocol, so performance is standardised and predictable, allowing mixing and matching of certified products. Control wiring (known as the DALI bus) can run between luminaires, sensors and interfaces in any sequence, while a wireless version is also available. The system uses a digital signal for more precise and flexible control, in turn facilitating energy savings. Identifying the areas that will return the


most significant savings requires effective data harvesting. Armed with the correct information, it becomes possible for building owners and managers to target their energy conservation efforts. A DALI network consists of at least one


application controller, which can control, configure or query each device utilising bi-directional data exchange. By gathering information from various input devices, such as occupancy sensors, push-buttons, rotary controls and touch panels, lighting usage patterns and trends soon become apparent. Moreover, updates to the DALI protocol now


enable control gear (such as LED drivers) inside the luminaires to monitor and report the real-time energy usage of the light fixtures.


MORE CONTROL, LESS ENERGY A building’s lighting efficiency is often poor because lights are active when and where they are not required. To counter this situation,


24 ENERGY MANAGEMENT - Summer 2021


some large lighting-control projects feature thousands of PIR sensors that detect occupancy in different parts of the building and activate/deactivate lighting accordingly. Estimates vary depending upon building type,


but lighting often accounts for around 20-30% of energy costs. As a result, DALI can significantly affect energy management, with occupancy- based data analytics providing an extremely useful tool for facility managers tasked with driving down electricity consumption. Another effective way to reduce energy usage


is via light-level sensors. In short, it is possible to create DALI-based lighting-control systems in tune with available natural light. This method can also leverage factors such as the time of day, the sun’s position in the sky and even the time of year, thus minimising the energy consumption demands of any supporting artificial light.


REAL-LIFE SUCCESS STORIES There are many examples of DALI having a major impact on energy consumption, not least Manchester Airport, where the recent Terminal 2 extension uses a dynamic, energy-efficient lighting- control system involving nearly 20,000 DALI drivers. As a central objective,


the system had to deploy new control methods through APIs (application programming interfaces), and maximise the energy-saving opportunities in a building


different light manufacturers and control strategies, DALI proved essential to the project because of its flexibility with respect to monitoring and energy efficiency in an ever- changing environment. The availability of sensors for presence and lux levels, as well as switches for absence detection and overrides, was pivotal, along with luminaire performance diagnostics data based on operational hours. At Manchester Airport, lighting monitoring


and control takes place via a BMS at the system’s head end. The project features 19,546 DALI drivers, over 3,000 sensors and 532 application controllers that are connected to a single BACnet IP-converged network. Users can interface all system components on a single dashboard. Another major project, Crossrail in London,


features DALI technology at seven central stations on the new Elizabeth Line, where it plays a key role in minimising energy consumption and supporting the goal of delivering energy-efficient, sustainable solutions for London’s transport network.


DALI Lighting Awards winner Laing O’Rourke utilised DALI within the Manchester Airport Terminal 2 Extension and New Piers project (www.dali-alliance.org/awards/winners.html).


www.energymanagementmag.co.uk


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