Green light

The Lighting and building management systems in place at The Department of Conservation's head office form an important part of its energy-conscious agenda. Systems are interconnected with such fine tuning that lighting might register a different illumination depending on whether it is a cleaner or office worker swiping their entry card.

Harding Electrical undertook installation of the cabling and fittings, while ECOsystems designed the labyrinthine systems of lights and sensors that optimise light levels and minimise the building's pull on the national grid.

Harding Electrical's work started with demolishing the existing infrastructures to make way for the progressive new systems, says director Damian Moloney.

"A new DOC switchboard was then set in place, together with distribution boards and the extensive switching and cabling running throughout the offices and the high-tech DALI, or digital addressable lighting interfaces," he says. "It is the DALI lighting that gives Conservation House's lighting its pinpoint sensitivity."

DALI is a protocol for digital communication between lighting devices. It is a subsystem that offers add-ons and features for the practical application of lighting management systems. DALI works by providing each individual light fitting, or ballast, with its own digital address, so lights can be controlled automatically within a group or individually. Preset groups of lights can also be changed without the need for rewiring.

Harding Electrical commissioned ECOsystems to design the systems required by the engineering consultants that the electrical company would then install.

ECOsystems' focus is energy auditing, project management, energy controls and implementation and it was chosen for its experience on large commercial projects.

Director of ECOsystems Scott Martin says the brief handed to the company by Sinclair Knight Merz was to maximise energy savings through intelligent lighting control utilising occupancy detection and daylight harvesting.

"Every desk on the office floors has a component of natural daylight and at some stage during the day, the lights in each area were to be dimmed in conjunction with the input of natural light to achieve these savings," says Martin. "This has been achieved through DALI light fittings with C-Bus logic inter-connectivity."

C-Bus, by Clipsal, is a microprocessor-based control and management system that controls lighting and other electrical services.

Occupancy detectors were also mapped out by ECOsystems and used in conjunction with the light level sensors throughout the building.

"We used a Clipsal C-Bus DALI gateway to talk to the DALI light fittings this meant that each light fitting could be addressed and treated as an independent light circuit without having to run a separate cable to the switchboard," he says. "Clipsal worked with us to design custom housings that would allow their implementation within the context of the exposed ceilings areas that resulted from the use of chilled beams throughout."

ECOsystems developed and tested a logic module within C-Bus that enabled complete control of the light fittings. This custom logic control module interfaces between the building's lights and sensors.

"Without the use of a C-Bus logic engine there would have been no other way to achieve the degree of control that was required," says the director.

In addition to light-level control, the C-Bus system is set up to interface with security, fire and building management systems. Based on occupancy, the C-Bus will control the air conditioning in respective areas for additional energy savings, and there is facility to extend the system to control presentation and conferencing equipment.

For further information on Harding Electrical, phone (04) 499 9003, fax (04) 499 8804. Or visit the website: www.hardingelectrical.co.nz.

For further information on ECOsystems, phone (04) 566 3666, fax (04) 566 0666. Or visit the website: www.eco.co.nz.

Story by: Trendsideas