Overview.

Project No.	264-E
Industry or Sector	Commercial Office Building
Energy Use	Lighting
Date Added	January 2006
Abstract	The use of high efficiency T5 fluorescent lamp and electronic ballast, and a redesigned high efficiency reflector enabled Genesis Now to halve the electricity consumption while increasing light output, while improving lighting quality and working conditions for staff, and slashing maintenance costs.     Detailed design refinement and off-site manufacture of lighting modules make the lighting upgrade affordable.

Situation

The fluorescent lights in an office building had become difficult to maintain. Lamp holders were failing due to UV embrittlement of the plastic, and these were difficult to access.  Replacement of the lights was impractical, both because they were in an imperial ceiling grid, and because many of the lights included a “light air boot”. (The lights formed part of the air-conditioning system; replacing the lights would necessitate modifying the supply air system.

The client had also trialled retrofitting electronic ballasts, but this had proved uneconomic because the lights were difficult to work on in-situ (labour costs alone were more than $150 per fitting).

Genesis Now proposed modifying the existing light chassis, to:

• reduce maintenance costs,
• reduce electricity costs, and
• improve the quality of illumination, and so improve the working environment.

Our initial approach was to design an improved reflector, to enable a single 36 watt fluorescent lamp to replace the two existing 36 watt lamps.  However, it soon became apparent that the geometry of the fitting and limitations of “T8” lamps (26 mm) lamps meant that this approach would not equal the performance of the existing combination of two lamps and a mediocre reflector.

The next approach was to consider using a single T5, 54 watt lamp.  Our calculations showed that this should provide 50% more light than an unmodified light with two new 36 watt tri-phosphor lamps.   We built a prototype and conducted tests, which confirmed our calculations that the 1 x 54W fitting would produce 50% more light than an unmodified light with two new tri-phosphor lamps.

Further refining the reflector and other design parameters allowed us to use a single 39W T5 lamp, resulting in lighting electricity savings of 50%, while providing slightly more light than the existing fitting with a clean reflector and two new 36 watt lamps.

We were also able to reduce the capital cost of the modification, thus increasing the number of lights which could be modified within the budget and so further increasing the energy savings.

Lighting Performance

The illuminance with the modified lights is between 100% and 200% of the illuminance before modification.

Non-Energy Benefits

As well as halving energy consumption, costs and related greenhouse gas emissions, the lighting conversion has achieved the following significant benefits:

• elimination of light flicker and strobing, reducing eye strain and increasing productivity
• increased safety (automatic shut-down of faulty lamps)
• extension of lamp life by 50%, reducing lamp and labour costs.
• replacement of 470 fluorescent lamps of varying age and condition, reducing maintenance costs. The 235 new lamps should not require replacement for an average of 8 years.

Some studies have concluded that eliminating fluorescent flicker results in a significant reduction in headaches and absenteeism, but this has not been investigated yet for this project.
Note that even a 1% improvement in staff productivity would be more valuable than the energy savings achieved.

Additional Benefits from T5 Conversion

The following benefits were achieved as a result of the conversion to a single T5 lamp, which would not have been achieved by the installation of electronic ballasts in the existing light fittings:

Replacement of all lamp-holders. About half of the existing lamp-holders had been replaced and the remaining half were in poor condition.  This replacement eliminated a significant maintenance liability.

Halving the number of lamps to maintain.

Converting to a lamp with a much lower mercury content.

Investment Performance

Note:  These savings and benefits exclude the largest but hardest to quantify benefit of an improved working environment, and so healthier, happier and more productive staff.

Waste Materials

Materials consumption and disposal was reduced by reusing the existing light fitting body. All fluorescent lamps were assessed.  Those which were near new were cleaned and boxed, and left with the client for use in other buildings.  Those which were in good condition were donated to a local school.  Those which could not be reused were sent to a licensed lamp recycler, who recovers the glass, mercury and other metals (and prevents these materials from entering landfills). 

All assemblies removed from the old light fittings were disassembled at our premises, with more than 90% of material diverted from landfill.  Components in good condition were stored for possible reuse. Ferro-magnetic ballasts and damaged gear trays were given to a metal recycler.  Only broken lamp holders and some wiring assemblies were sent to landfill.

Pricing

Please call to discuss the viability of retrofitting the fluorescent lights in your office.

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