Monday 22 August 2011
Retrofit T5 Conversion
IntroductionThis guidance deals with the retrofit conversion kits that allow T5 fluorescent tubes to be used in light fittings designed to use T8 format tubes. The conversion kits also change fittings with mains frequency ballasts to operate using more energy efficient, high frequency ballasts. These kits are not recommended for fittings that already use high frequency ballasts, due to the reduced potential for energy savings.
Depending on the exact choice of T5 tube, energy savings of up to 45% are achievable (but this may bring with it a reduction in illumination levels).
The Technology
Conversion kits are available which will work in existing fittings containing switch start, mains frequency fluorescent tube ballasts. The kits convert the fittings to use energy efficient, high frequency ballasts and accommodate the smaller diameter T5 tube.
There are two main types of conversion kits (see picture below):
Common problems
Installing the retrofit units is a straightforward process, with few difficulties likely to be encountered.
Converting fluorescent tubes from T8 to T5 may cause a reduction in overall lighting lux levels, which, if lighting levels were previously only just acceptable, may cause them to become unacceptably low. In these situations it is important that in choosing between standard and high efficiency T5 tubes, the higher lumen tubes are selected, maximising the light output.
Some fittings may offer restricted physical access, which may influence the type of adapter chosen.
Similarly, in some mirror reflector light fittings, the presence of the baton type adapter’s “spine” can interfere with light output.
In all cases, it is recommended that a small trial installation is carried out before any bulk orders are placed.
The business case
The business case for a typical retrofit conversion unit, installed in an existing 1,500mm mains frequency switchstart fluorescent fitting, is as follows:
The T8 tube plus the mains frequency ballast would use a total power of typically 73W, whereas the T5 tube plus high frequency ballast uses typically 49W, a saving of 2W.
Assuming that the lighting is used 12 hours per day, 5 days per week, 52 weeks per year, a total of 3,120 hours per year changing the lighting would save 75 kWh per year. With a typical electricity cost of 7.9 p/kWh this would save £5.93 per year, leading to a payback period of approximately four years.
There are also savings as the tube life is increased, electrical circuit losses reduced and less demand on the air conditioning due to the lower heat output from more efficient lighting.
However, in this particular case, the light output would be reduced by 17% which may not be acceptable in some cases.
Depending on the exact choice of T5 tube, energy savings of up to 45% are achievable (but this may bring with it a reduction in illumination levels).
The Technology
Conversion kits are available which will work in existing fittings containing switch start, mains frequency fluorescent tube ballasts. The kits convert the fittings to use energy efficient, high frequency ballasts and accommodate the smaller diameter T5 tube.
There are two main types of conversion kits (see picture below):
- Tube end type – kits which include a replacement starter and two separate components to fit over each end of the T5 tube. The tube is then slotted into the existing fitting.
- Baton type – one piece kits which slot into the existing fitting and into which the T5 tube is placed.
| The following table illustrates the correspondence between the T8 and equivalent T5 fluorescent tubes using the retrofit kits. The power consumed by T5 tubes is less and, although there may be a reduction in brightness, the lifetime of the tubes will typically increase from 15,000 hours to 20,000 hours. | ||||||||||||||||||||||||||||||||||
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| Application The kits can be used on lighting in many commercial and office settings, as well as other locations such as schools. The conversion kits can accommodate most tube lengths, and allow for changes from T12 and T8 tubes to T5 tubes. They are not currently available for 8 foot fittings. The majority of the savings come from converting from mains frequency to high frequency ballasts. Savings will be significantly reduced if your existing lighting already has high frequency ballasts. The following table describes the recommended lux levels for a selection of different tasks (Lux is a measure of the brightness produced by the lighting). Given the lux levels required, and the distribution of the light fittings, a selection needs to be made between standard and high efficiency T5 tubes so that the maximum energy saving is made without impairing lighting levels. A supplier should be able to assist with this process. | ||||||||||||||||||||||||||||||||||
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| For an existing lighting installation that is more than 10 years old, it may be more cost effective to completely renew the light fittings (rather than convert them). This will allow the additional benefits of higher light output ratio fittings to be used. Further guidance is given in the How to implement office lighting refurbishment guide, downloadable from the Carbon Trust website. Specification checklist The following table lists the key parameters that you will need to define through discussion with your supplier in order to specify an appropriate retrofit conversion kit and tubes. | ||||||||||||||||||||||||||||||||||
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| Commissioning procedures The installation and commissioning of the plug-in retrofit conversion units and tube should be done in accordance with the manufacturer’s recommendations. It is however advisable to trial the retrofit units and tubes before switching all fittings to ensure that the specification has been accurate. Ensure that the correct lighting lux levels are maintained and checked (see Application section). If electrical wiring is altered electrical checks should include installation and commissioning to the current edition of BS 7671 IEE Electrical Wiring Regulations. |
Installing the retrofit units is a straightforward process, with few difficulties likely to be encountered.
Converting fluorescent tubes from T8 to T5 may cause a reduction in overall lighting lux levels, which, if lighting levels were previously only just acceptable, may cause them to become unacceptably low. In these situations it is important that in choosing between standard and high efficiency T5 tubes, the higher lumen tubes are selected, maximising the light output.
Some fittings may offer restricted physical access, which may influence the type of adapter chosen.
Similarly, in some mirror reflector light fittings, the presence of the baton type adapter’s “spine” can interfere with light output.
In all cases, it is recommended that a small trial installation is carried out before any bulk orders are placed.
The business case
The business case for a typical retrofit conversion unit, installed in an existing 1,500mm mains frequency switchstart fluorescent fitting, is as follows:
The T8 tube plus the mains frequency ballast would use a total power of typically 73W, whereas the T5 tube plus high frequency ballast uses typically 49W, a saving of 2W.
Assuming that the lighting is used 12 hours per day, 5 days per week, 52 weeks per year, a total of 3,120 hours per year changing the lighting would save 75 kWh per year. With a typical electricity cost of 7.9 p/kWh this would save £5.93 per year, leading to a payback period of approximately four years.
There are also savings as the tube life is increased, electrical circuit losses reduced and less demand on the air conditioning due to the lower heat output from more efficient lighting.
However, in this particular case, the light output would be reduced by 17% which may not be acceptable in some cases.
Is it worth upgrading my lighting systems?
Upgrading equipment and systems
Make the most of natural light by creating lighting zones parallel to the windows and switching them separately. Then, when there’s enough daylight, the lighting zone near the window can be switched off or dimmed without leaving other zones with too little light.
2. Zone lighting
Within every large workspace there’ll be areas that require different levels of lighting – where closer proximity, more efficient task lighting would improve the working environment. Install specific controls to service these zones, so that task lighting can be switched on when it’s needed and off when it’s not. If you are uncertain where the main work stations will be in a workspace do not light the whole area to the maximum level required for the tasks. Instead, light to a lower level and provide extra task lighting for work stations.
1. Occupancy sensors
Why light empty spaces? Occupancy sensors, which switch off lights when a space isn’t being used, can reduce lighting costs by 30%.
2. Install daylight sensorsLighting a space artificially when daylight is already doing the job is a waste of energy. Light sensors (photocells) switch off or dim artificial lighting when there’s sufficient daylight. They’re particularly useful for outside lights, and can pay back their costs within a year.
Zoning
1. Switching in parallelMake the most of natural light by creating lighting zones parallel to the windows and switching them separately. Then, when there’s enough daylight, the lighting zone near the window can be switched off or dimmed without leaving other zones with too little light.
2. Zone lighting
Within every large workspace there’ll be areas that require different levels of lighting – where closer proximity, more efficient task lighting would improve the working environment. Install specific controls to service these zones, so that task lighting can be switched on when it’s needed and off when it’s not. If you are uncertain where the main work stations will be in a workspace do not light the whole area to the maximum level required for the tasks. Instead, light to a lower level and provide extra task lighting for work stations.
Lighting controls
1. Occupancy sensors
Why light empty spaces? Occupancy sensors, which switch off lights when a space isn’t being used, can reduce lighting costs by 30%.
2. Install daylight sensorsLighting a space artificially when daylight is already doing the job is a waste of energy. Light sensors (photocells) switch off or dim artificial lighting when there’s sufficient daylight. They’re particularly useful for outside lights, and can pay back their costs within a year.
Making the right change....things to think about.
Safety
- Is emergency escape lighting required/provided?
- Have potential hazards been identified and properly lit?
- Could there be issues with fluorescent lighting and rotating
machinery (the stroboscopic effect)?
Task requirements
- Have tasks been properly analysed and adequate lighting provided?
- Does the lighting scheme provide the right amount/direction of light to meet the task?
- Has the proper colour rendering requirement for the task been assessed/provided for?
- Have any potential problems with glare been considered and dealt with?
Lighting appearance
- Will the lighting installation be appropriate for the specific application and for the architecture of the building?
- Have you assessed the colour appearance of the light source (with reference to the specific situation/task)?
Energy efficiency
- Has the most appropriate and energy efficient equipment been used/specified?
- Have you considered how to use daylight to best effect?
- Have appropriate lighting controls been used/specified?
- Does the design properly and fully address energy efficiency?
Carbon Care trust advise on why lighting maintenance is a MUST!
Maintenance musts:
1. Cleaning schedule
It may sound simple, but cleaning windows and skylights regularly lets maximum daylight into the building. Similarly, cleaning light fittings and sensors will make your lighting more effective, especially for systems with automatic dimming control systems.
2. Checking sensors and controls
Dust can obscure lighting control sensors: clean these regularly so they work more efficiently. Check that timers on lights are showing the correct time (remember to alter them when clocks change), and make sure the settings reflect how your business works.
3. Replacement schedule
Replace blackened, flickering, dim or failed lamps immediately. In some circumstances failed lamps can still use energy and waste money. Consider early replacement of lamps in your maintenance schedule if your lamps are hard to reach (see below).
4. Maintenance schedule
Like a shopping list, a schedule is there to make sure you don’t forget anything. Start by walking through all the elements of your lighting system, creating a checklist that will help to optimise its efficiency. By noting light levels in each space and any issues with the lighting and equipment, you’ll build up a useful picture of where problems exist, and when they arise. This will help you create the optimum maintenance schedule for your building.
Create a maintenance schedule that works for you. For example, if you have lots of lights mounted high up (e.g. in an industrial site), put in the schedule that they should all be replaced at the same time. This will lessen the risk of lamps failing, and save you the difficulty and additional expense of replacing inconveniently positioned bulbs individually.
Important: Bulbs shouldn’t only be replaced when they fail – their output depreciates with use, so they should be replaced when they get to about 50% below the initial value.
Manufacturers and suppliers can supply you with the light depreciation curve for the particular lamp. When it’s time to replace bulbs, think about the efficiency and application of the ones you’re using. The tool in the Upgrading lamps and luminaires section will help you establish if you could save energy by choosing different bulbs.
As well as having a maintenance schedule, you should also be aware of housekeeping issues
Thursday 18 August 2011
Is LED lighting is cost effective alternative for energy saving?
Is LED lighting is cost effective alternative for energy saving?
A Long term alternative to wasteful halogen
As the world looks to meet targets for carbon emissions, one of the ways to reduce energy use is through LED lightning.
While halogen are commonly used, there are a number of benefits with the continuing uptake of LED technology.
The emergence of the technology being used in both commercial and domestic environments has been attributed in some quarters to increased efficiencies in chip technology. As well as being long lasting, containing no harmful chemicals and not requiring any time to warm up, LED lights also mean an extremely small carbon footprint compared to other lighting types.
And according to IMS Research LED lighting offers between 50 and 90%reduction in energy usage as compared to halogen lamps.
They also have extremely long lifetimes, free users from frequent lamp replacement, and small carbon footprints, making it an environmentally-friendly technology.
However one of the problems with LED lighting is the initial expense, though as IMS Research has told us this is expected to come down as the technology hits the mass market.
According to LED suppliers the price of a halogen lamp is approximately £3.50 per unit, compared to the typical cost of a MR16 LED replacement being just over the £13 mark Overall halogen lamps, to name one type, are costly due to their poor efficiency.
Apparently a typical 50 watt halogen lamp produces 22 lumens per watt of energy produced, with a lifespan limited to around 2,000 hours. With most of its energy being given off as heat there is substantial waste. In comparison, an LED replacement is said to produce the same amount in terms of lumens, for just 7 to 11 watts of power.
Combined with an expected lifespan of around 50,000 hours there is obviously significant cost benefits after the initial outlay. There is also a heat reduction giving advantages where lighting can be mean a need for air conditioning, meaning further expense.
Over the coming years the technology will become more widely used too. It is said that over 70% of newly constructed buildings will feature the lighting by 2014.
This means that LED lightning will not be used as a decorative addition to traditional lighting, but be the main bulk of lighting.
So with prices expected to fall by between 10 in some years, even 40% in others, as components become more cheaply produced LED lighting will likely present itself as an even more viable option. Ref: Matthew Finnegan in Londo
Digital Addressable Lighting Interface or DALI or simply lighting control systems
The Benefits and Application of DALI Lighting
The term DALI is appearing more and more within the intelligent building industry, but what is it and how can business and home owners benefit from it…
DALI (Digital Addressable Lighting Interface) provides detailed, digital control over lighting, from one user-friendly interface. With an impressive and simple wiring system DALI is able to both send and receive signals from individual lamp ballasts, allowing the user to manage lighting on a group or individual level, and also to receive a certain level of feedback from each ballast on usage and maintenance. This flexibility in control combined with communication between all elements makes for a highly functioning and user-friendly system, configured to require minimal cabling for ease in installation.
The capabilities of DALI lighting controls are well suited to commercial buildings, particularly to hotels, and now an increasing number of large private residences are also turning to DALI for lighting control. To highlight an example within the commercial sector, DALI can be hugely effective when implemented into a conference facility. In a room with say 16 light sources DALI can simultaneously control each on an individual level to gain optimum control over the space as a whole. Controls can also be linked to other electronic devices within the space, for example, on beginning a presentation, the room lighting can dim near to the screen to improve viewing, whilst simultaneously brightening in other areas, for example at the back of the room to highlight doors or refreshment areas.
With the use of lux and movement sensors DALI lighting can automatically provide ‘daylight harvesting’ – the maintaining of an optimum level of light, by only topping-up the natural daylight in a room as and when required. This facility invariably has a huge effect on energy saving, and is particularly useful in public areas such as offices, hotel foyers, health centres, schools and universities.
In a situation where a room has multiple user areas i.e. an open plan office, over-all control can be allowed to be over-ridden on a local level by the occupant/s of any given area, giving them freedom over their own space. On a larger scale where the system spans over rooms and floor levels this function can also be used to monitor usage, and then to charge accordingly on a tenant-by-tenant basis, useful in both residential and commercial settings. The ‘conversation’ held between each lighting element and the central controller also allows for automatic maintenance alerts to be flagged, minimizing repair times and maximizing occupant / tenant experience.
In a situation where a room has multiple user areas i.e. an open plan office, over-all control can be allowed to be over-ridden on a local level by the occupant/s of any given area, giving them freedom over their own space. On a larger scale where the system spans over rooms and floor levels this function can also be used to monitor usage, and then to charge accordingly on a tenant-by-tenant basis, useful in both residential and commercial settings. The ‘conversation’ held between each lighting element and the central controller also allows for automatic maintenance alerts to be flagged, minimizing repair times and maximizing occupant / tenant experience.
In privately owned residences DALI can be implemented to achieve optimum energy efficiency and comfort for residents. With digital dimming and lamp selection the user has incredible flexibility and the ability to enter pre-sets i.e. bright morning kitchen lighting for reading the paper with breakfast, and low evening wall lighting for relaxing after work. The settings can also be arranged to gradually fade or interact with other controlled electrical devises within the home.
It is accepted that best practice when looking to utilise the benefits of DALI is to use KNX protocol to provide the overall system back bone. Switches, movement detectors and any other field devices would be provided by the KNX system along with the high level of intelligence and control which is necessary
It is accepted that best practice when looking to utilise the benefits of DALI is to use KNX protocol to provide the overall system back bone. Switches, movement detectors and any other field devices would be provided by the KNX system along with the high level of intelligence and control which is necessary
Ref: INTECH.com
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