Making light work

As energy prices continue to rise, owners and occupants of commercial buildings are looking for new ways to make significant energy cost savings. The ideal solution is proving to be eliminating the wasteful use of lights.

According to lighting management firm Ex-Or, lighting can account for up to half of a commercial building’s electricity costs. And with electricity usually accounting for half of the total energy bill, there is the potential to save 25% of the entire electricity load.

Despite this opportunity to save significant amounts of energy, in the past building managers and owners have been going down the more traditional routes to energy saving: more efficient heating/ventilation plant, building insulation etc. Now, the price of oil has been reaching all-time highs and businesses are being warned they face increases of between 30-50 % on their energy bills.

So the time has come for those in charge of energy costs in industrial and commercial buildings to look at other ways of curbing rises in energy costs, and lighting control is becoming the preferred candidate.

The essence of lighting control is to ensure the lights are on only when they are required, and always deliver the optimum brightness levels. The system achieves this by continuously monitoring the presence of occupants and measuring the amount of natural light available, then ensuring the lights automatically switch on and off, and dim or brighten, according to need.

Savings will depend on the type of building, but cuts of up to 80% can be achieved by automatically controlling the lighting in a warehouse. The payback – the period of time it will take for the system to pay for itself thanks to the resulting energy cost savings achieved – would be less than 12 months.

For a typical office building comprising open plan and cellular offices, the savings would be in the order of 40-60% with a three to five year payback period.

“Energy managers and buildings and facilities managers are facing increases in their power bills of up to 50% and are desperate to make energy savings,” says Ex-Or md Neil Jones.

“Yet few realise that lighting is the biggest electrical load in a commercial building. As an example, if the lights are left on permanently in a single, small cellular office that has just four light fittings, the cost of energy is £210 a year. Multiply that over a typical large commercial building with hundreds or even thousands of luminaires across the site, and the potential for saving energy is enormous. Indeed, the savings can often exceed those made by any comparable investment in energy conservation measures.

“Obviously, savings do vary depending on the size of the building and its usage, but in a commercial building savings in the order of £10 000 to £20 000 – each and every year – are commonplace where Ex-Or lighting management systems and controls are installed.”

Ex-Or launched its range of lighting management systems and controls in 1984. Since then, its customers have cut a staggering £72 million off their energy bills (equal to 36 million tonnes of CO2 emissions).

So how does automatic lighting control work? Put simply, sophisticated yet discreet equipment using a variety of detection technologies – passive infrared, microwave, ultrasonic – continuously monitors the working areas and detects the slightest movements that signify people are present. Photocells measure the amount of natural light available and tell the luminaires whether or not to switch on, and at what levels of brightness.

Lighting controls are available in increasingly sophisticated forms. Ex-Or’s MLS Digital Managed Lighting System allows groups of luminaires to be individually controlled in predetermined work zones, in an open plan office for example. They are capable of swapping occupancy information with other luminaires within the building – useful for delivering the correct level of lighting to occupants in work zones and holding lights on automatically in circulation areas and corridor routes. Think of it as creating the ability for an entire commercial building’s lighting system to think for itself and make intelligent decisions about saving energy.

The systems can be further enhanced by building in scene selection capability, whereby occupants can choose previously set lighting scenes to best suit the current use of the room at the touch of a button. A lighting scene in a cellular office could be brightly lit for office cleaning, then dimly lit for an av presentation.

Lighting control is fully automatic, yet seamless to the building occupants – they will not realise the lighting system is thinking for itself. But when there are occasions when an occupant wants to alter the light level in their own working space for any reason, this is easily done by using his personal handheld remote control unit.

So lighting control really does deliver significant energy savings. What other benefits does it offer building owners and buildings and facilities managers? One is “future-proofed flexibility” in terms of office layout. In today’s dynamic business environment, nothing stays still. Work groups continuously change within open plan offices, and traditionally electricians had to be employed to alter wiring and luminaire positions to accommodate any new working patterns in the office. With a sophisticated lighting system such as the Ex-Or MLS, the need for rewiring is completely eliminated. Individual luminaires and groups of luminaires can be easily reprogrammed again and again using a remote control, handheld programmer.

Meeting health and safety legislation is an increasing concern for managers of commercial buildings. With the number of computer screens now in use, adherence to the Health and Safety (Display Screen Equipment) Regulations 1992 is vital. Automatic lighting control ensures that these latest regulations are being met.

Another benefit is difficult to measure but is evident in every office setting where automatic lighting control has been installed. It creates an ideally lit environment – not too bright, not to dim – in which staff can work productively and effectively.

And the installation of lighting control need not require an upfront investment. Currently, energy saving projects can qualify for interest-free loans from the Government-backed Carbon Trust. SMEs (firms with up to 250 employees and turnover of up to £25 million) can receive an Action Energy Loan in the form of a lump sum of between £5000 and £100 000 to pay for an energy saving project such as lighting control. The interest-free repayments are made from the resulting energy savings.