Archive for the ‘Lighting’ Category

Reflect on Fluoros

Thursday, January 8th, 2009

WME The Environmet Business Magazine had this article “Reflect on Fluoros” in their Dec 2008 issue. The article started bt stating that “While the EPOCH’s promise of spending nothing to get better power at a lower cost provides a very compelling case for change, there is an even simpler way to cut energy usage when it comes to lighting - a way that migh even be easier than rending staff to switch off unused lights”

The article goes on to explain Carbonetix’s Mirrorlux technology and the significant benefits, both financial and environmental, of using this technology with a delamping strategy. It the goes on to stae that “this technology proves cutting energy is not brain surgery and is not always going to cost a mint. Anyone looking for a suitablr cliche should try - every little bit helps”

The article concludes by stating that ” Many companies would benefit if their leaders spent less time rent seeking around carbon reductions and more time taking up existing options tahta are already cost effective.”

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.

How we have kept our energy use 75% lower than a typical office of our size

Wednesday, January 7th, 2009

This week marks exactly one year since we first moved into our current office of 267 m2. Readings of our electricity meter show energy consumption was 30.2 kWh/m2 for the year. Thats all our energy use - we don’t have a gas connection - and includes heating and cooling of the office. To put this in context, this is lower than any of Australia’s famous green buildings. How have we achieved this?

CarbonetiX office

First, we operate the heating/cooling system manually, and only when needed. Most of the year its off. We get good ventilation through the building by opening the front and back doors. HVAC control

Second, we have delamped - that is removed one lamp from each double fluorescent light fitting, and fitted Mirrorlux reflectors behind the remaining fluoro tube. delamped fluorescent light fitting

Third, we have a good switch off culture. The printer goes off at night. Staff only switch lights on when needed. Computers are unplugged at night time.
printer signage

Fourth, we use laptops, which use less than half the power of desktop computers.

Fifth, we use occupancy sensors to control lighting. If a workspace is empty, the light goes off.

occupancy sensor

Sixth, our internal phone and internet network equipment goes off overnight, using a simple plug in timer. We use VoIP phones with power over network, power over network was chosen deliberately to enable this out of hours shut down.
timer on phone and internal network

Seventh, our servers go off automatically each night after the backup, and are turned on manually the next day.
servers switched on manually

Eighth, in the one office with windows the lights stay off most the time.
daylit office

Ninth- we use a kettle rather than a boiling hot water unit. The boiling hot water unit in the photo has been disconnected.
boiling hot water unit replaced with kettle

Tenth- we have removed the tubes in the outside light of our sign. We don’t operate at night, and there is no need to have it illuminated.
sign with power disconnected

In December last year we installed skylights. As they have only just been installed they wouldn’t have contributed much to our savings last year. But in 2009 they should help keep our energy consumption even lower.

There isn’t a lot of rocket science in what we have done. The biggest savings have come from how we operate the heating and cooling - and we haven’t spent a cent on control systems. Energy conservation is good for the environment, and has saved us money. Assuming the previous tenant used 130 kWh/m2/year (pretty typical for an office this size) last year we saved $4,000 and 35 tonnes of greenhouse gas.

Can LED lights replace fluorescents?

Wednesday, December 17th, 2008

LED lights are seen by many as the next big thing when it comes to lighting. But do they live up to their promise?

LED tube

LED tube

Over the last few months we have been researching and testing LED tubes. These tubes are the same shape as a fluorescent tube, and have hundreds of LEDs on them. To summarise our research results:

  • The performance of LED tubes has improved greatly over the last 12 months, particularly in terms of total light output.
  • Quality of manufacture is still of concern (one of the LED tubes in the photo has partially failed).
  • Many tubes now have a very good “daylight” light colour, although some of the ones we tested were quite blue.
  • We are not yet at the point where a LED tube can substitute a 36 watt tri-phosphor fluorescent, but if the technology continues to advance as it has the performance may match fluorescent tubes within the next three years, but with much lower power input.
  • Pricing is still high, but as lighting performance improves the range of applications where LEDs can be used will increase. This should lead to economies of scale and price reductions.

Skylights slash our need for artificial lighting.

Monday, December 8th, 2008

Last weekend six solar tube skylights were installed in our office, which occupies the top floor of a two storey building. The skylights have eliminated the need for artificial lighting in thirteen of our work spaces.

It was amazing watching the reaction of staff as they came in this morning, many couldn’t contain their excitement. “Its so much brighter.” “The quality of light is fantastic.” “We don’t need the lights on at all.”

The cost installed was $5,550. Our landlord agreed to pay half of the costs. As we were pretty frugal with our lighting to start with, and it was already efficient, the lighting energy cost savings won’t be large, in the order of $500 a year. We may have to run the air conditioner more in summer because of the heat gain from the skylights, but this may also cut heating energy use in winter. Assuming it balances out the payback for us as tenants will probably be around 5 to 6 years in terms of energy savings. However daylight also makes the workplace more attractive, and may improve productivity. So there will be other benefits in addition to the cost savings. And of course the greenhouse gas savings will reduce the amount of green-power we need to purchase. If we were buying black power the skylights would be expected to save us around 2.5 tonnes of greenhouse gas a year.