Energy & Efficiency

Energy & Efficiency

Comparison of Energy and Lighting Efficiency Technologies

Basic Definitions and Basic Terminology

The application of energy efficient lighting ultimately leads to significant savings in electricity demand. Reducing energy demand, therefore, is both economically sensible and environmentally responsible.

A number of terms relating to lighting and efficiency measures are commonly used in documents and websites on energy and lighting, but they are regularly used incorrectly or out of context, and can be misleading particularly in product marketing material.

Energy Efficiency - is a measure of

the amount of energy which any technology can convert to useful work; technology with a higher energy efficiency will require less energy (power) to do the same amount of work. Energy Efficiency for lighting relates to the total input power of the lamp and ballast circuit for a particular lamp and ballast combination, not just the lamp.

Lighting Efficiency - is a measure of how much visible light is given off from a lighting source per unit of energy. It is measured in lumens per watt (lumens/watt). Improved lighting efficiency by itself does not automatically result in reduced energy (power) consumption unless the lighting design (number and layout of fittings, tubes, type of ballast, control devices etc) has been addressed as well.

Efficacy - same as Lighting Efficiency, (lamp light output (lumens) per unit of energy input (watts).

Ballasts - all fluorescent lamp fittings come with either a magnetic ballast or an electronic ballast. Magnetic ballast lamps are far more common but an increasing number of electronic ballast fittings

are being installed. High-performance magnetic ballasts are now readily available and can replace older inefficient ballasts.

Voltage Reduction (magnetic ballast only) - voltage reduction and the consequent current reductions across fluorescent lamps fitted with a magnetic ballast results in increased energy efficiency and increased lighting efficiency. Copper and iron energy losses in the ballast rise by the square of the current. Therefore, the energy/power loss in a ballast drops over-proportionally when the current is reduced. Lighting efficiency also increases as voltage and current are reduced.

Electronic Starters -

are very efficient fluorescent lamp starters (replace conventional inefficient glow starters) that pre-heat the tube cathode filaments for efficient start, prolonged tube life, flicker-free operation and should never need replacing.

Voltage Reduction (magnetic ballasts only)

BMASS Power Saver is a type of voltage reduction device. It reduces the power demand of fluorescent lamp fittings by reducing the load voltage and current, with a resultant improvement in power factor. The simple formulae for an AC circuit is:

Power = Voltage x Current x Power Factor

Power savings are achieved by reducing the voltage to the fluorescent lamp fitting by approximately 15% (240v - 204v relative to supply voltage) which in turn reduces load current by 20 - 30%. It results in a reduction of power consumed by a theoretical 33%, in practice, energy savings of around 30% are regularly achieved. An over-proportional drop in energy loss across the ballast occurs as a result of the same over-proportional current drop when supply voltage is reduced. Variations do occur depending on the type of lamp fitting, type of ballast and type/age of tubes. Load current reductions achieved are generally higher for older ballasts (i.e. Class C) where the rated nominal ballast loss is higher, an advantage for existing buildings.

Voltage reduction results in an increase in lighting efficiency (lm/w) of >20%, enabling a significant reduction in power/energy (w) to be applied with no perceptible loss in light out (lm).

The key advantages of voltage reduction techniques, are summarised as:

power / energy consumption reduced by up to 33%

energy loss reduced by >65% across all magnetic ballasts

light efficiency / efficacy increased by >20% at reduced voltages and currents

reduced EMR emissions

reduced stress on tube assembly due to flicker free operation and reduction of voltage/current across the lamp after start-up

reduced heat emission from ballast and lamp fitting

Lighting Efficiency - "Efficacy"

A reduction in supply voltage and the subsequent over-proportional current drop, results in increased lighting efficiency. The following diagram clearly illustrates the significant increase in lighting efficiency (efficacy) as voltage is decreased. Note the point at which the efficacy of the magnetic ballast fitting and the electronic ballast fitting are the same. The application of voltage reduction and high-performance magnetic ballasts (EEI B1) will result in an increase in lighting efficiency of >20% from a Class C ballast; the same increase as claimed with electronic ballasts. Therefore, magnetic ballasts enable the lighting efficiency improvements to be immediately converted into power/energy saving. On the other hand, the claimed lighting efficiency benefits of electronic ballasts cannot be easily transferred into energy saving without a physical change to the lighting design.

The lighting efficiency of EEI A1 (without dimming) and EEI A3 electronic ballasts is in fact less than 10% more than a high-performance magnetic ballast at full supply voltage, not >20% as stated in most publications. At reduced supply voltages, it drops to 0% in the band 208-216v depending on the type of ballast (B1/B2) and continues to fall if voltage where dropped further. Power Saver is normally set to reduce voltage to around 204v (15% of supply voltage) but this can be varied.

Triphosphor fluorescent tubes have a much higher lighting efficiency to the older Halophosphor tubes (no longer manufactured or imported into Australia). T8 Triphosphor tubes have a 20% higher lighting efficiency (efficacy) when compared to a T8 Halophosphor tube and 50% from a T12 Halophosphor. Triphosphor tubes are used with both magnetic and electronic ballast fittings. Lighting upgrade programs using a combination of Triphosphor tubes and voltage reduction technology provide significant energy savings and improvements in lighting efficiency, without the need for any change to the lighting design. Although in theory additional energy savings can be achieved by either removing some of the individual tubes (de-lamping) or lamp fittings, consideration must be given to consequence of creating shadows in the workplace, especially in office and work environments and shopping display areas.

Source: European Copper Institute - original test data adjusted to 240V mains

Energy Efficiency

Energy Efficiency for lighting relates to the total input power of the lamp and ballast combination.

The Australian and New Zealand standard MEPS for Fluorescent Lamp Ballasts is shown below. The MEPS stipulates the maximum input power for fluorescent lamp ballasts and is the combination of lamp power (shown on the left side of the table) and the maximum energy loss across the ballast (shown on the right side of the table). The loss is defined as a 'nominal ballast loss', with some manufacturer's high-performance magnetic ballasts having lower loss levels than stipulated in the MEPS table. Significant additional reductions in ballast loss occur as a direct result of voltage reduction with magnetic ballasts and are not reflected in the MEPS table; typically reductions of >65%. A high-performance magnetic ballast with voltage reduction could in some cases actually be classified as A1/A3 in terms of nominal ballast loss.

Lamp fittings with electronic ballasts must have the lower wattage tube (see Lamp Power column) installed to realise the stated input power saving, otherwise there will be no additional power saving. By way of example, in the case of a standard 36W lamp fitting, if the ballast was changed from magnetic to electronic the lamp would also have to be changed to a 32W tube otherwise there is no effective saving.

Significant improvements in energy efficiency are achievable with high-performance magnetic ballasts and voltage reduction due to:

a large reduction in actual ballast loss

increased lighting efficiency enabling reductions in supplied power to the ballast and lamp circuit

Lamp Power		Maximum Corrected Input Power of Ballast and Lamp Circuits
Lamp Power		Energy Efficiency Index (EEI) Classification
50 Hz (magnetic)	HF (electronic)	A1	A2	A3	B1	B2	C	D
15W	14W	≤18W	≤16W	≤18W	≤21W	≤23W	≤25W	>25W
18W	16W	≤21W	≤19W	≤21W	≤24W	≤26W	≤28W	>28W
30W	24W	≤33W	≤31W	≤33W	≤36W	≤38W	≤40W	>40W
36W	32W	≤38W	≤36W	≤38W	≤41W	≤43W	≤45W	>45W
38W	32W	≤40W	≤38W	≤40W	≤43W	≤45W	≤47W	>47W
58W	50W	≤59W	≤55W	≤59W	≤64W	≤67W	≤70W	>70W
70W	60W	≤72W	≤68W	≤72W	≤77W	≤80W	≤83W	>83W

	- never common in Australia and are not considered appropriate for local product comparisons
	- C ballasts are no longer able to be sold in Australia
A1	- dimmable electronic ballasts
A2	- non-dimmable high-performance electronic ballast
A3	- low-performance electronic ballast
B1/B2	- high-performance magnetic ballast

Source: Australian and New Zealand Standard MEPS - Fluorescent Lamp Ballasts

High-Performance Ballasts

Fluorescent lamp fitting ballasts are readily available from numerous manufacturer's in both high-performance magnetic and electronic. Low-performance electronic ballasts are also offered as solely purchase-cost-oriented and are not an alternative for the high-performance magnetic or electronic ballast. Standard and low-performance magnetic ballasts (C and D) are no longer permitted to be sold in Australia. Consequently, any product comparison with other than a high-performance ballast (magnetic or electronic) could be considered misleading and unfortunately, is common practice when reporting on the claimed merits of electronic ballast lamp fittings and some energy saving products.

High Performance Magnetic Ballasts (B1 and B2) are High Power Factor (HPF) ballasts (>0.9), as are electronic ballasts.

Not all electronic ballasts are dimmable. Only high-performance EEI A1 electronic ballasts are dimmable. Additionally, these ballasts unless actually dimmed, are only as energy efficient as a low-performance EEI A3 ballast. Dimming of the lamps is not suitable for many applications.

A consolidated manufacturer's overview of high-performance ballasts, their characteristics, relative reliability (life and failure rates), energy saving, recycling and disposal issues, and relative life-cycle costs is available here.

All comparisons of performance between high-performance magnetic ballasts and electronic ballasts (high-performance and low-performance) assume the magnetic ballast light fitting has a conventional glow starter installed, including the manufacturer's overview above. The installation of low-cost electronic starters significantly enhances the overall performance of those fittings, something that is rarely published in any objective analysis.

Electronic Starters

Fluorescent light fittings commonly are supplied with 'conventional glow starters'. Glow starters have a limited life and are normally replaced along with each tube replacement. Annoyingly, they flicker on start-up (stressing the cathode and reduce potential lamp life) and continuously flicker when a tube or starter is starting to fail.

The lifetime of a fluorescent lamp is dictated by the life of its cathode filament assemblies. With electronic starters, the cathodes are pre-heated continuously until they reach full emission temperature. At the end of this pre-heating-period the cathodes will be emitting freely over the entire area and a low energy impulse is then delivered across the tube to achieve ignition. This intelligent function saves the cathodes from early erosion and gives them a longer life. The blast of the paste of the cathodes will be avoided and you will no longer have black spots at the end of your tubes as you always have with a conventional glow starter. In good quality starters, once the lamp is running, a safety monitor comes into force, constantly measuring the power being used by the lamp. In the event of an abnormality, which can occur with a major supply irregularity or at the end of the lamp-life, a safety monitor will disconnect the circuit and avoid overheating or damage to other circuit components.

Electronic Starters provide:

start after optimum pre-heat time for maximum lamp life (pre-heating is essential to reduce the wear effect of starting procedures and not all electronic ballasts perform this essential function)

flicker free and smooth start of fluorescent lamps

no replacement of starters (10 year warranty with life expectancy in excess of 20 years)

very low EMI during start (less than /-70 db compared to glow starters)

no residual current unlike conventional glow starters

also instant start versions, cold storage room versions and more

reduce the costs for maintenance and replacement of tubes and starters (tube life doubled)

economic and environmentally friendly (extended tube life reduces the amount of waste from tubes, particularly mercury)

Electronic starters installed in high-performance magnetic ballast light fittings negates many published advantages of electronic ballasts. Importantly, in addition to the advantages just outlined, the use of reduction voltage technology will realise significant energy or power savings, not possible with electronic ballasts alone.

Palm Step Electronics manufacture a range of electronic starters to suit most applications.

BMASS distributes the very efficient PalmStep OKOSTART (OKO 2 and OKO 6) electronic starters, suitable for most fluorescent tubes. Click here for further details.

Further Technical Reports

Energy Efficient Fluorescent Lighting Solutions - read more on the application of these technology towards 'Best Practice' fluorescent lighting standards: Power Saver voltage reduction, high performance magnetic ballasts (EEI B1 and B2), electronic fluorescent starters, quality T8 triphosphor tubes, and quality fluorescent luminaire.

Technical Guide 5: High Performance Fluorescent Lighting: The Next Steps- Including the Cases for High-Performance Magnetic vs High Performance Electronic Ballasts - a detailed technical analysis of a wide range of factors to be considered with regard to the performance of magnetic and electronic ballasts for fluorescent lighting, and questions the 'electronic ballast or bust' drive currently in the marketplace. The purpose of this document is to promote awareness and stimulate debate, in order to reduce energy consumption through lighting efficiency and achieve the most desirable environmental outcomes. (Source - ecospecifier - Technical Guide 5)

Efficient Lighting - European Copper Institute - read more on basic facts and advanced information on ballasts for fluorescent lamps from the European Copper Institute.