Introduction

For over 12 years, Chalmor has been leading the way in forecourt energy savings. Chalmor’s Endurance induction lamp fittings offer proven technology - forecourt pioneers who installed this technology 10 years ago still report no failures!

Canopy lighting costs and efficiency levels are coming under ever-increasing scrutiny, as companies spend anything between 30 and 60% of their electricity budgets on lighting alone. Most petrol retailers are looking at three main options for their needs - namely inexpensive metal halide lamps, induction lamps and light emitting diodes (LEDs).

How they work

• Metal halide (MH) lamps consist of an arc tube (also called a discharge tube or "burner") within an outer envelope, or bulb. The arc tube may be made of either quartz or ceramic and contains a starting gas (usually argon), mercury, and MH salts. Traditional quartz MH arc tubes are similar in shape to mercury vapor (MV) arc tubes, but they operate at higher temperatures and pressures. Typically, lamps have a life expectancy of 15,000 hrs and are very efficient initially, but depreciate heavily over their life.

• Induction is the process of transmitting energy via an electro-magnetic field. The light emitting gas inside the lamps is energized by passing alternating current through a coil, or inductor. Induction lamps are similar to regular fluorescent lamps, but they don't have electrical contacts to conduct electricity from the fixture to the light-emitting gas inside the lamp. Additionally with a lamp life of greater than 60,000 hours and efficiency maintained throughout their life, they are a popular solution.

• LED lighting is based on semi-conductor diodes. When a diode is switched on, electrons are able to recombine with holes within the device, releasing energy in the form of photons. This effect is called electroluminescence. The colour of the light is determined by the energy gap of the semiconductor. For commercial lighting, there are two main methods of producing high intensity white-light using LEDs. One is to use individual LEDs that combine red, green, and blue light to produce white light. The other is to use a phosphor material to convert monochromatic light from a blue or Ultraviolet LED to broad-spectrum white light, in a similar way to a fluorescent light lamp. The useful life of an LED is typically 50,000 hours, subject to the environment placed. LED’s are the least efficient of the three, but maintain their performance relativity well throughout their life.

Metal Halide v Induction

Although Metal Halide fittings may appear to be a cheap solution they have three major disadvantages: it is difficult to control fittings in line with occupancy and daylight, lamps are lower efficacy and have a shorter life compared to the other HID sources.
The below table: Shows typical energy savings achieved by installing Chalmor’s Endurance fitting and Chalmor’s Universal Lighting Controller (UNI –L) against Metal Halide fittings.

Key benefits

• Total savings of 29,028kWh per annum, representing a forecast load saving of 67%
• Savings of 12.48 tonnes of CO2 emissions
• Lifetime cost reduction of 53% (in energy consumption, lamp replacement and maintenance)
• Up to 100,000 hours lamp life with 5 year guarantee
• Delivers minimum energy consumption
• Offers controllability through Chalmor’s Lighting Controls
• Endorsed by the PRA and DTI
• Improved quality of lighting, providing:
o greater security and safety for staff and customers
o Enhanced trade.

Induction v LED

While there is a lot of hype around LEDs and they are often portrayed as the future of lighting, a close look at the issues involved point to induction lighting offering a more cost-effective and efficient option for canopy installations.

 “Tested products showed that offered claims of efficacy are overstated by 25 to 35% and Lumen output is overstated by 30 to 95%”. Energy Star testing results (August 2007)

• Induction lighting is currently more efficient than LED lighting. Commercially available induction lamps typically have conversion efficiencies of 65 to 90 Lumens per Watt (L/W). Most LED commercial applications are recording 35 to 60 L/W*

• Taking a 200W commercial/industrial fixture as an example, an induction lamp will provide between 15.1 and 57.5% more light than LED fixtures for the same amount of energy input. A 150W Endura lamp will produce more light than a 200W LED, resulting in better lighting and lower running costs**
• Another advantage of induction lighting is its lifespan. A product such as the Chalmor Endurance range has a useful lifespan of at least 60,000 hours. In some of Chalmor’s projects Endurance lighting schemes have lasted over 100,000 hours. Most LEDs struggle to reach 50,000 hours, with little or no real world evidence to support the long claims.
•  Induction lamps can easily be replaced within the existing fitting.
• With LED systems, however, the whole unit usually needs to be replaced. This is because a 200W LED fixture will feature an array of 20W or 25W LEDs. These require custom heat sinks which are very difficult – and often impossible to replace. LEDs also use drivers which often incorporate electrolytic capacitors which have a limited life – the LED’s might last but you still need to service the drivers.
• In forecourt environments lighting maintenance and replacement can be costly and difficult, often requiring the use of cherry-pickers to access the units. A more durable and long-lasting option is clearly desirable.
• Induction fixtures are between 50 and 75% cheaper to buy than equivalent LED versions, although it is thought this gap will become smaller as LED manufacturers capitalise on economies of scale. However LED costs are unlikely to change in the near future as diode demand is greater than supply output and thus effecting diode quality.
• It is difficult to achieve LED colour consistency within fixtures in general, this is due to tolerances within the manufacturing process, consequently diodes from a range of white “colour bins” are often used within an individual fixture which effects light output and colour rendition.

• But perhaps most significantly, the LED's energy efficiency for commercial use is in doubt. According to Richard Stevenson of IEEE Spectrum (August 2009): “The blue light-emitting diode, arguably the greatest optoelectronic advance of the past 25 years, harbours a dark secret: Crank up the current and its efficiencies will plummet. The problem is known as droop, and it’s not only puzzling the brightest minds in the field, it’s also threatening the future of the electric lighting industry. In commercial terms this means a greater number of LED’s are required to be running at a low current to produce anything like reasonable efficiencies; clearly this increases the cost of the fixture as a greater number of expensive LED’s are required.
“It is very clear that there are products on the market which by no means achieve what the manufacturer promises“  Report: “OpgeLed” by Dutch Metrology Institute (NMI/VSL)
• The effects of heat on the LEDs can also be an issue and can often lead to a reduction of luminous flux (light output), Increase of wavelength (colour shifts more towards red), reduction of forward voltage (voltage drop across the LED)  and a shortening in the lifetime of the LED

Conclusion

As the technology behind LEDs is refined during the coming years, they will become a more cost-effective product for forecourt applications. But until then, Endurance induction lighting provides by far the lowest life cost solution, delivering all the hype and promises of LED’s in a relatively low cost tried and tested package.

We would really like to hear your experiences of LED lighting, so please post a response!

* and ** Figures taken from a study by L. Michael Roberts