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With 18 months having passed since the opening of Heathrow T5, Andromeda has commissioned an energy performance study of the campus-wide intelligent lighting control system in association with BAA to highlight the many benefits of intelligent control systems and key issues currently faced by the industry.
As the industry landscape enters a phase of immense shift and change, both in terms of environmental concerns and financial pressures, decision-makers and technical innovators must change their costing mindset in order to face upcoming challenges. One of the biggest obstacles that the building services industry must overcome is the prevalent perception towards project costing, which considers only the immediate outlay of building service technologies at the design phase. This traditional approach can restrict innovation and prohibit the use of energy-saving technologies over cheaper alternatives. However, choosing to take a whole life costing approach will help the client achieve the right solution financially and environmentally. The big question is, ‘is the cheaper solution the most cost effective?'
Heathrow Terminal 5
Heathrow T5 is a landmark project both for Andromeda and BAA, and demonstrates how short payback periods and the energy-saving potential of the Andromeda integrated control solutions can be achieved.
Andromeda delivered a control solution based around a KNX bus infrastructure, using DALI as the central protocol for luminaires. The entire system sits on the BAA IP network, interfacing with the campus-wide monitoring system via OPC. The solution is primarily a lighting control system, with emergency light testing and monitoring, digital dimming, virtual energy metering of lighting loads, monitoring of third party equipment such as disabled WC alarms, along with items of major plant.
Andromeda hase been monitoring the performance of the system over time in order to provide the client, BAA, with real data that will demonstrate the energy-saving credentials of the system in practice, and consolidate the positive operating performance results to date. The data compiled expresses energy-savings data both as carbon savings and financial return on investment. The Energy Study is a working document, currently under review by a number of external auditors. However, the figures that have already been validated provide exciting evidence that integrated control technologies can achieve short payback periods.
The study pinpointed six key areas for savings:
1. Digital dimming (DALI)
Dimming should no longer be regarded as an extravagance, but as an integral part of an energy-saving strategy. If you take the power consumption versus dim level for a typical T5 light fitting as utilised throughout the terminal, the power consumption decreases as the dim level decreases.
Using the Andromeda DALI / KNX system vast energy savings can be achieved by reducing light levels against external brightness or simply reducing levels in all areas.
2. Output limitation
A large area for saving is output limitation, where Andromeda trim back generous allowances for light levels to the original specification. This is best demonstrated by the car park, where prior to opening the lighting levels were limited to a maximum of 20% as the 80% maximum previously employed was considered too bright. At 20% dim level, there has been no complaint that the environment is too dingy, and the associated power consumption is 25% of the maximum. This illustrates how simple savings can be achieved without compromising the lighting design.
3. External daylight control
This area covers three strategies, which all make maximum use of natural light:
- a. Dusk to Dawn Control - the lighting is turned on when the ambient light level drops below a certain lux threshold in the evening, and turned off in the morning. Lighting under this form of control in London is off for an average of 52% over the year.
- b. Automatic Daylight Control - certain areas of T5 have a control strategy where set lighting scenes change in response to the externally measured lux level. These scenes can change as frequently as every half hour.
- c. Constant Light Control - a sensor continuously measures the ambient daylight level and dims the lighting up or down so that a constant light level is maintained.
4. Presence detection
Andromeda utilise intelligent presence detectors to control lighting in areas which are not consistently occupied. Lighting will activate when a person enters the area and switch off, or dim to a minimum safety level, after a set period of time when the person leaves. This is crucial for energy saving in an airport environment, as back of house areas and toilets for example could otherwise be left on at all times. Using DALI control, light levels can be dropped as a warning before being switched off.
5. Master headend control
Andromeda's system is connected to a master headend control, known at T5 as the BSI. This allows the client to have complete control over the system and its maintenance. Time based scenarios are held within distributed control modules which are updated by the master headend control, offering savings through optimised switching programmes. The master control is a business tool and can be used to manage, monitor and record data from the system, which in turn will support the maintenance strategy for the site.
6. Maintenance labour savings
Coupled with the energy-saving measures detailed above, the system also enables savings to be realised on the labour-intensive maintenance normally associated with a system of this size, through its fully automated emergency light testing and monitoring.
Making savings
In conclusion, from the initial study it can be seen that Andromeda's system will reduce the carbon emissions at T5 by 5,800,000 kg per annum, or achieve cost savings of around £950,000 per annum, giving the client a payback period of under five years. These savings can be potentially further consolidated as the system is recognised through the Carbon Trust's Enhanced Capital Allowance scheme.
Martyn Suggett, portfolio technical leader for BAA states: "I am more convinced than ever that the T5 Lighting Control System will deliver significant energy savings against conventionally lit Passenger Terminal Buildings within the BAA airports group, and it has quickly been recognised as the benchmark for all major lighting installations within BAA in the future. We are now working on a day to day basis with the system and looking at ways to further refine and enhance it, increasing subsequent energy savings. The system therefore acts as a constant operational tool, helping BAA tackle rising energy costs proactively, where conventional systems could not evolve in this way."
As this Energy Study shows, BAA has taken a whole life costing approach to this iconic project, and invested in the future of the building and its environment, resulting in the lighting control system achieving an exceptional payback period. The system has also been officially recognised for its innovation through winning the DALI AG Award 2008.
