Carbon Conservation & Energy Efficiency


Bruce Rowse & Team

Posts Tagged ‘energy efficient lighting’

Is Plasma Light a serious competitor to LED light?

Thursday, February 5th, 2009

Controlled Plasma (CP) lighting technology is the latest of a number of emerging innovative lighting technologies that inadvertently help reduce GHG emission through energy efficiency. In fact its Melbourne inventor Graeme Huon (formerly and acoustics engineer) asserted that “If we were to replace 75 % of lights in homes with these globes in the next five years, we could save building one new power station”.

Cold cathode fluorescent lighting (or CCFL) has been around for a few years in the form of inductive lighting. However, what sets CP globes aside from the rest is that it is the first of its kind to be able to be used in homes as well as for commercial applications due to its affordability and design.

CPL Light On

CP Light On

What is a CP globe? Graeme Huon explains: “It is a light source that utilises three existing filament-free light technologies; neon, cold cathode and high intensity discharge along with a new type of controller to regulate the way it works. That way you get flicker-free light and cool running temperatures. It only uses 5 watts, is dimmable and has a lifespan of 20 000 hours”. These together with good colour rendition and with very good light flux levels make it a real alternative to LED lamps and actually surpass CFL lamps in many ways.

To further simplify matters the GU10 globe is incorporated into a downlight fitting (similar in appearance to many existing 50 watt halogen fittings) and is fully sealed to keep out insulation, bugs and heat. This creative downlight is also so versatile that the same fitting can be used as a gimbal or flush type fitting or one can remove the globe with the controller and simply insert it into an existing downlight luminaire. It is fully compatible with existing wiring and comes in two versions; with a plug-in lead or as a quick connect system to be used by electricians. Due to their tri-phosphor coating they are available in warm white and cool white but in the future there may even be ‘party light colours’.

But are they a direct replacement for 50 watt halogen downlights? Well not quite. CP lights do have very good lux levels but they have a different directivity of light. CP lights don’t have a bright spot like halogens so they are not directly suited to long throw or spotlight applications. However, they are a possible alternative in some cases as long as one is aware that they provide slightly less but more uniform light. This means that for the same given area you will have to use more CP lights than you would use halogen downlights but since they only consume 5 watts each this is not a problem.

LED technology is developing at a rapid rate with better-brighter light levels and possible dimming capabilities in the near future. Nevertheless they are unable to match the low wattage for the same amount of light or the colour temperatures of CP lights. LED lights also run at a higher temperatures so large heat sinks need to be fitted to cool them. This doesn’t mean that LEDs are worse or can’t compare to the quality of CPs. It is more of a case of the LEDs being suitable for different applications and commercial use due to their own design features and price.

As for the CFL alternatives, they still use up to 11 watts and produce less light. Finally the cost of a CP unit cannot be matched by any of these two. They are rumoured to sell for under $60 per unit, which is less than half of an equivalent LED fitting and probably the same as a non-dimmable CFL fitting with lamp. CP light fittings will be distributed under the Kambrook name and are designed and produced by CP Envirotech.

(References: G Magazine April 2008; Green Lighting in Electrical Connections December 2008).

How good is T5 fluorescent lighting?

Thursday, January 8th, 2009

T5 fluorescent lighting has been around for a while now, but is not yet widely used in the manufacturing or warehouse sectors. Paul Smith has compared T5s with metal halide, and is interested in how T5s compare in terms of their total environmental impact.

As Paul writes, T5s strike faster, have good colour rendition, and a well designed T5 high bay luminaire, with 4 tubes, can be more efficient than a metal halide lamp, and have less lumen depreciation over its lifetime.

Both metal halide and T5 lamps contain mercury. T5 refers to the diameter of the tube, with T5 tubes being 5/8″ (16mm) in diamater. “Standard” fluorescent tubes are called T8s and are 8/8″ (25mm) in diameter. With a smaller diameter T5s use less glass and mercury than a T8 of comparable brightness.

Having said that, quite a few myths have developed around T5 lamps and as a result many people believe they are the best thing since sliced bread was invented. The luminous efficacy in lumens per watt of good T5 lamps approaches 105 lumens per watt, but this is only slightly better than the best T8 which is near 100 lumens per watt. Large wattage metal halides also have luminious efficiencies approaching 100 lumens per watt. However, like most things, just because a lamp is a T5 doesn’t mean its luminous efficacy is above 100 lumens per watt, there are many T5s on the market with an efficacy of only 80 lumens per watt.

The uptake of T5s has been much greater in the commercial building sector, particularly in offices, than in manufacturing and warehouses. The reason for this I believe is LEED (in Australia Greenstar) and other standards where building designers are seeking maximum efficiency in lighting. These drivers aren’t yet as strong in the manufacturing and warehouse sectors. Certainly in our work we mostly come across T5s in office buildings which are pursuing a high green star rating. And metal halide highbay light fittings are still much cheaper and much more readily available than T5 highbay fittings.

If you are designing a new commercial building it makes economic and environmental sense to use T5 lighting with high efficiency luminaires. The luminaire (light fitting) chosen is important too. The purpose of the luminaire is to direct the light coming out of the tube to where it is needed. Low efficiency luminaires are inefficient at doing this. To get the most out of T5 lighting you also need to be specifying high efficiency luminaires.  A big advantage T5 lights have over conventional T8 is their use of an electronic ballast, which extends lamp life, eliminates flicker, and reduces lumen depreciation.

For a commercial building retrofit the use of high efficiency replacement T8 tube in a double fluorescent luminaire and fitting of a specular reflector behind the tube to increase the efficiency of the luminaire enables the removal of one tube and halves energy use of the fitting. This is called delamping (more at our delamping webite). This provides larger energy and cost savings and is less expensive and more reliable than fitting T5 adaptors – devices than enable a T5 tube to be used in a T8 fitting. T5 tubes fitted with T8 adaptors have a lower luminous efficacy than the best T8 tube, so their use is not advised, not withstanding the marketing hype surrounding T5 adaptors.

In new warehouses in my opinion T5 high bay luminaires as described by Paul are far superior to metal halides. Paul outlines several reasons for this. The instant start of T5s is in many case perhaps the biggest advantage. When undertaking energy audits of warehouses I have usually see the high bay lights running all day, even though different sections of the warehouse will often be empty. This is very wasteful. Unfortunately HID lamps, such as metal halide, high pressure sodium, and the less efficient but inexpensive mercury vapour all take a long time to warm up, and therefore its not practical to switch them off in empty spaces. Forklift operators and staff just aren’t prepared to wait 10 or 15 minutes for the lights to warm up to full brightness.

T5 or T8 linear fluorescent lamps don’t have this problem. So they can be controlled by motion or occupancy sensors. In many cases the hours of operation of lights in warehouses could be reduced from 10 to 12 hours a day to less than 4 hours a day with the use of sensors and T5 high bay fittings. Lighting energy costs can easily be halved.

Another metal halide replacement is the induction lamp, which has the advantage of instant start as well, but can in some cases be retrofitted into the existing high bay fittings. Their luminous efficacy is also pretty good, they are easily dimmed (good where daylighting controls are installed), and prices are coming down. Induction lamps also have a very long lamp life, in the order of 50,000 hours (compared with 14,000 hours for a good metal halide and 20,000 hours for a good T5)

LED lighting is rapidly becoming more efficient, and we have tested LED fluorescent tube replacements achieving over 70 lumens per watt – which is a big improvement over the 40 to 50 lumens/watt we were seeing 12 to 18 months ago. If the luminous efficacy of white LED technology continues to improve this quickly, and prices start to drop, then we may find in five years time that LED is better than all other forms of lighting.