Lighting control – the efficient energy saver

June 2011 – As energy costs escalate, facility managers are under immense pressure to reduce costs without compromising building performance. As GARRY LOWE from Systems Intelligence reports, lighting control is an obvious place to start.

The drive towards increased energy efficiency should be a professional imperative, not only as a response to increasing government focus and shifting market demand, but also as an opportunity for significant running cost reduction. The release of new government energy reduction schemes such as Commercial Building Disclosure program, as well as the ever-widening scope of the Green Building Council of Australia’s range of Green Star rating tools, highlights the importance of the operational performance of existing buildings.

Garry Lowe.

For property owners and managers, lighting control is one of the easiest, least disruptive and fastest energy efficiency solutions capable of delivering substantial cost savings. Traditionally in Australia there has been limited choice for lighting control solutions; as a consequence, pricing has been driven higher. However, with technological advancements such as the introduction of KNX, an open architecture system, there is not only greater choice but also greater tailoring, flexibility and seamless integration into an existing building.

LIGHTING & ENERGY CONSUMPTION
Lighting is a significant proportion of overall energy use in commercial properties. For example, tenant lighting is responsible for 67 percent of tenancy energy usage and 32 percent of an entire commercial building’s¹ energy usage. As such, it is one of the key focus areas for energy reduction. At first glance, it can appear as though the investment costs for lighting control are greater than the expenditure for a conventional lighting installation; however, this perspective changes when you look at entire lifecycle costs. The Department of Climate Change and Energy Efficiency has recently released findings that savings of between 20–70 percent can be achieved in a typical office, with payback periods of approximately five years, depending on the current installation and usage patterns. The payback period for a lighting energy efficiency upgrade could be well within the term of a typical ‘3×3’ lease (three years with a three year option) in the Australian market.
According to a ZVEI (Association of the German Electrical Industry) study, energy consumption for building lighting can be reduced by up to 80 percent by using intelligent building systems such as KNX. (See Figure 1 below.)
Reduced energy consumption is only one potential saving; the use of open standard technology such as KNX can deliver further cost savings through:

• reduced installation costs
• more efficient commissioning
• reduced facility management and maintenance costs, as there is transparent acquisition of important building data and improved processing of fault messages.

LIGHTING CONTROL FUNCTIONS
There are a range of different lighting control functions. Depending on the needs of your buildings, the correct design may contain:

• occupancy detection – the simplest way to control lighting to meet your requirements is based on the presence of users in the room. The room is only lit automatically when someone is there.
• time and date scheduling – by synchronising the on/off times of each fixture with the occupancy patterns of each building, the occupant can eliminate wasted energy by ensuring that lights are only turned on when needed
• daylight harvesting – light sensors detect the light level outside; the indoor lighting is then adjusted to the desired level via a dimmer or independent ballast control
• light zoning – provides the ability to reconfigure lighting zones using virtual software groups, which can be modified or deleted through software. This eliminates the need for expensive re-wiring.
• after-hours control – only the set of lights that illuminate the office, hallway, washroom and other predefined work spaces are activated if and when a person enters the office
• façade and blind control – in winter blinds are lowered at night to conserve valuable warmth in rooms. In summer, they close to keep out the strong sun and reduce the need for air-conditioning.

POTENTIAL SAVINGS
The potential energy savings are dependent on the mix of functions used, as shown in Figure 2 below from the study, “Energy saving and efficiency potential through the use of bus technology as well as room and building automation,” by Biberach University of Applied Sciences, Institute for Building and Energy Systems in 2008.
This study showed that up to 25 percent of savings could be gained easily through simple daylight harvesting and occupancy detection in an open plan office.
So what are the critical things to look out for when assessing lighting control systems?

• an ‘all in one’ system, instead of separate control solutions – it is important that the system you choose is capable of all possible functions/applications.
• flexibility, supporting all communication media as well as adaptable to both new and old buildings. Building can be quickly adapted to accommodate new demands.
• durability, a system that has been used around the world for a considerable period. It is also important that components from the first generation are still compatible with present product lines.
• communication, system implementation has the ability to use a buildings existing communication infrastructure. Additionally data can be transmitted externally for security or maintenance purposes.

SUMMARY
The benefits of installing coordinated lighting control solutions are as follows:

• substantial energy and cost savings can be achieved with intelligent lighting control in comparison to conventional lighting technology
• the maximum energy saving potential is achieved using a combination of different lighting control functions
• savings are fundamentally in the double-figure percentage range
• the required investment in intelligent lighting control is generally low in comparison to structural modifications to buildings
• The payback periods are relatively short and are generally within one to five years.

Footnote
The tenant energy management handbook – Sustainable Development Authority 2000.

Garry Lowe is director of Systems Intelligence, a new leading-edge building and lighting control company specialising in the latest open architecture technology. Systems Intelligence delivers a full range of customised control solutions, from design through to commissioning and post-installation servicing.

More information
Systems Intelligence
www.systemsintelligence.com.au
Email Garry Lowe at garry.lowe@systemsintelligence.com.au
KNX Association
www.knx.org