1.What is an LED light?
2.In what stage is the development of LED technology today?
3.In what kind of applications are LEDs used?
4.Can LED street lights efficiently replace HID lamps?
5.Why don´t LED´s function as efficiently in traditional fixtures?
6.What are the advantages of LEDs over the new energy efficient compact fluorescent lights?
7.Why are LED lights considered better than incandescent and CFL lamps?
8.How bad are mercury and lead?
9.How can I differ between low quality and high quality LED luminaire?
10.Where can the LED street lights be seen?
11.What is the investment cost of LED street luminaires compared to other technologies?
12.What are the main disadvantages of LED technology?
13.What is the lifetime of LED luminaires?
14.What is junction temperature and how it affects LED efficiency?
15.Why is the life span of an LED measured as lumen depreciation?
16.Is there a warm-up time needed when switching on a LED luminaire?
17.How mechanically durable is a LED luminaire?
18.How accurate is the color reproduction of LED light?
19.Can LEDs be dimmed?
20.Does dimming LEDs decrease their lamp life?
What does the IP and IK rating means?
22.Do LED luminaires contain any harmful substances?
23.Is there any infrared radiation coming out of LED luminaires?
24.How is with ultraviolet radiation in LED luminaires?
25.What is the importance of full cut off lights?
26.How much can I save with LSL® lights?
An LED light is a solid-state lamp that uses light-emitting diodes (LEDs) as the source of light. It is a small electronic device (a semiconductor diode) that emits light when electricity passes through it. It is one of the most efficient and prosperous light sources available on the world market. According to the latest research and further development advances of the LED industry, LED light technologies will be the leading lighting force in the future.
2. In what stage is the development of LED technology today?
LEDs are dramatically increasing light output, efficiency, reliability and are becoming increasingly more brighter. The lumen output of LEDs has almost doubled in the last two years. At the end of 2009 the LED technology was mature enough to enter the high demanding market of outdoor illumination and to successfully compete with existing street lighting technologies.
3. In what kind of applications are LEDs used?
LED technology has been used for several decades in various applications. White LED lamps have achieved market dominance in applications where high efficiency is important at low power levels. Some of these applications include flashlights, solar-powered garden or walkway lights, and bicycle lights. Monochromatic (colored) LED lamps are now commercially used for traffic signal lamps, where the ability to emit bright monochromatic light is a desired feature, and in strings of holiday lights.
LEDs are widely used in automotive industry, military and yachting lighting. Its use in domestic electronic appliances and high tech devices is rising. LED lights have also become very popular in gardening and agriculture by 2010. First used by NASA to grow plants in space, LEDs came into use for home and commercial applications for indoor horticulture (aka grow lights). The incredible rapid progress of LED technology in the last few years enabled LEDs to become appropriate for use in general and outdoor lighting applications. Latest LED technologies used in LED luminaires are not only satisfying the needs of quality outdoor and general illumination but are already exceeding all other technologies in all parameters.
4. Can LED street lights efficiently replace HID lamps?
Super-bright white LEDs have the advantage of minimal lumen depreciation, better optical efficiency and high lumens per watt. This means these LEDs can be used to replace traditional HID luminaries. LEDs also have a vastly longer life span than traditional lamp sources. The fixture design also must be
designed to leverage these inherent advantages of LEDs. A Total Systems Approach is needed for an
LED product to bring all these features together.LED fixtures also have an environmental advantage in that they contain no mercury, last longer and produce less waste, and they are made from fully recyclable materials. When you compare average delivered lumens over the course of 60,000 hours, you’ll see that LED outperforms a 400 watt MH lamp operated in a horizontal position. (60,000 hours means three full life cycles of the HID.) The MH’s lumen depreciation, as well as optical and ballast losses, quickly reduce output of the HID
system. Note that there are three relamps over 60,000 hours. Conversely, LED has significantly better lumen maintenance and a more efficient driver. Also note that the LED fixture typically doesn’t need relamping from zero to 60,000 hours.
Result: the LED’s average delivered lumens is 74% higher than HID over 60,000 hours.
5. Why don´t LED´s function as efficiently in traditional fixtures?
Some manufacturers are producing LED bulbs, but the fact is that even if an LED bulb fits into an existing luminaire, the overall lighting output and performance cannot cope with the LED luminaire. The housing of LED luminaire is designed especially for the needs of LEDs to maximize its efficiency, performance and life-time. An LED lamp may physically fit into an existing housing but that housing doesn’t maximise the inherent qualities of the LED.
Standard housings aren’t designed to handle the challenges of LED thermal management, which is vastly different than thermal management for traditional incandescent or fluorescent lighting. Also, the optical design used in most traditional fixtures doesn’t maximize the LED’s efficiency. So conventional approaches to developing general illumination LED’s couldn’t be successfully applied to this new technology.
6. What are the advantages of leds over the new energy efficient compact fluorescent lights?
Like halogens or incandescent bulbs CFL’s are glass encapsulated rendering them quite fragile in nature. In addition CFL’s use a small amount of mercury and other heavy metals to produce their light rendering them non-recyclable and actually classifying them as hazardous waste after they cease to function. While far more efficient than halogens and incandescent bulbs CFL’s still use more energy than LED’s to produce the equivalent amount of light and their life span is five times shorter than LED’s.
7. Why are LED lights considered better than incandescent and CFL lamps?
Incandescent lamps and CFLs are potentially slow poison for your family, for you and for the environment. They contain hazardous substances like mercury and lead that are dangerous to your health and to the planet. The incandescent lamps and CFLs are being fast replaced with Eco-friendly LED lights because LED (Light Emitting Diode) lights do not contain any of these. LED lights also save far more energy, giving you a huge saving on your energy bills. Not only does this mean cost-saving for you, but it means conserving fast-depleting natural resources.
8. How bad are mercury and lead?
Here are some facts:
• Mercury was listed as a hazardous substance by the Agency for Toxic Substances and Disease Registry (ATSDR) and the EPA. The stipulated 2 mg./liter is often surpassed by most CFL manufacturers
• It only takes 1 teaspoon of mercury to permanently contaminate a 20-acre lake.
• Lead can cause neurological damage
• In children, exposure to mercury and lead can lead to learning disabilities and short-term memory loss.
9. How can I differ between low quality and high quality LED luminaire?
While choosing the right LED solution, you have to be aware, that LED technology has progressed rapidly in the past few years, that not all LED luminaires are created equal and that some manufacturers are offering extremely low cost options, which are inferior and of poor quality. Lumen output is only part of the story and can be misleading.
To fully evaluate an LED product one needs to review the overall system efficiency, optical control, thermal management of the LEDs, and know at what point in time the fixture will reach 30 percent lumen depreciation. Products with good optical efficiency and thermal management will be able to deliver more lumens, on average, than traditional HID products.
You have to inspect and test the product carefully. Only the technical characteristic of an LED cannot define the performance of an LED luminaire, since the system is composed from many critical components (like optics, thermal management, driver etc.) which are the key to optimized overall performance and efficiency.
You can recognize some low quality LED solutions by some common characteristics:
• unpleasant pale blue shine of light (color temperature 5.500 K and more)
• open casings and visible cooling ribs that indicate weakly solved problem of light heating (accumulating dirt on cooling ribs mean more maintenance cost, while openings in casing cause malfunction of electronics and reduced life expectancy)
• low quality components (optics, LEDs, driver, etc.) assembled together in manufacture with lack of technical expertise and quality control can cause uneven distribution of light beam, poor light and energy efficiency, glare etc.,
Always be sure that the manufacturer technical claims are not misleading but are verified with valid, acceptable and verifiable certificates. Also be sure that the manufacture has a solid, reliable background/history and can fulfill its warranty claims together with full customer support.
As the Department of Energy concluded in its Solid State Lighting Commercial Product Testing Program: “Until the field of SSL technologies and supporting knowledge matures, any claims regarding performance of SSL luminaries should be based on overall luminaire efficacy (i.e., from testing of the entire luminaire, including LEDs, drivers, heat sinks, optical lenses and housing).
10. Where can the LED street lights be seen?
LED street lights have been installed or announced for installation in several large cities as well as smaller cities throughout the world (Sydney, Boston, Worcester, Cleveland, Varna, Toronto, New York, Budapest, Los Angeles,…). Also a number of reports on the results of pilot projects for municipal outdoor lighting are available. Most of the cities that are following the policy of »green cities« have implemented LED technology in their future city development.
11. What is the investment cost of LED street luminaires compared to other technologies?
The cost of LED street luminaire is higher than that of other technologies, but when considering all the benefits and cost savings you will acquire with the right LED solution, there is no other serious alternative. Due to high energy efficieny your electricity bills will be drastically reduced, you will have no maintenance cost, you will lower your carbon emission and most important you will enjoy these benefits for decades, while return on investment will be realized in less than 2 years in most cases. With a solid financial plan your cash outlay will be minimal and with the realized savings may not cost anything at all compared to what you are utilizing at the present time.
12. What are the main disadvantages of LED technology?
The biggest disadvantage of LED technology is lack of education and knowledge about the technology itself and lots of poor quality solutions available on the market. There is a lot of misleading information on the market, coming from two main sources:
• manufacturers with low quality solutions, which are misleading the consumer withfalse technical characteristics and claims
• competitors which sell inefficient lighting technologies, which will soon be banned, so they can deplete existing inventories.
There are also a number of companies who claim to be original manufacturers but instead buy inferior quality LED luminaires from countries which mass produce the product, put their own brand on products, change origin and then sell to unsuspecting customers for a higher price.
Some street lighting tests were made while using old immature LED technology before the year 2009 when LED technology was mature enough to seriously compete with other street lighting technologies. Results of these studies are not showing the real condition of LED street light technology today.
The result of all this confusion and organized chaos, is that the current market is experiencing unjustified doubt about the LED technology that is currently on the market. Who do you believe? For the customer this is an extremely valid question. The weakness is not in technology but in cheap quality products and lack of knowledge.
Customers should always be careful and choose only verified high quality LED street light solutions from reputable manufacturers with solid backgrounds and proven history. While checking street lighting tests and reviews, you should always check which product was reviewed and from which year the product is available to avoid possible wrong conclusions.
13. What is the lifetime of LED luminaires?
LEDs do not burn out like incadescent light bulbs. Instead LEDs over their lifetime simply get progressively dimmer until they do not emit enough light to be useful. LED is considered to be no longer useful when it is emitting only 70% of the amount of light that it originally emitted. The time when 30% of lumen depreciation occurs is considered to be the “lifetime” of an LED. High quality LED luminaires can go up to 100.000 hours under good working conditions. The officialy acknowledged standard for life time of high quality LED luminaires worldwide is 50.000 hours. They are still working after that time and can go up to 100.000 hours but with lower lumen output. 100.000 working hours means a lifetime between 11 and 34 years depending on how long a LED luminaire is working every day.
|Working hours per day
|Life time of LED luminaire
|Street lighting technology
|Life time in hours
|50,000 – 100,000
|1,000 – 5,000
|Mercury vapor lights
|12,000 – 24,000
|Metal halide lights
|10,000 – 15,000
|High pressure sodium (HPS)
|12,000 – 24,000
|Low pressure sodium (LPS)
|10,000 – 18,000
|10,000 – 20,000
|Compact fluorescent light (CFL)
|12,000 – 20,000
|60,000 – 100,000
14. What is junction temperature and how it affects LED efficiency?
Junction temperature is the temperature at the point where an individual diode connects to its base.
Maintaining a low junction temperature increases output and slows LED lumen depreciation. Junction temperature is a key metric for evaluating an LED product’s quality and ability to deliver long life. The three things affecting junction temperature are: drive current, thermal path, and ambient temperature. In general, the higher the drive current, the greater the heat generated at the die. Heat must be moved away from the die in order to maintain expected light output, life, and color. The amount of heat that can be removed depends upon the ambient temperature and the design of the thermal path from the die to the surroundings. The Department of Energy advises: “Heat management and an awareness of the operating environment are critical considerations to the design and application of LED luminaries for general illumination. Successful products will use superior heat sink designs to dissipate heat, and minimize junction temperature. Keeping the junction temperature as low as possible and within manufacturer specifications is necessary in order to maximize the performance potential of LEDs.”
15. Why is the life span of an LED measured as lumen depreciation?
The life span of an LED is vastly longer than that of incandescent, fluorescent or HID lamp sources, generally lasting 50,000 hours or longer. Although the LED never really burns out, product life span is measured by lumen depreciation. The Illuminating Engineering Society’s (IES) current standard for calculating the life of an LED as the point at which the LED reaches 30 percent lumen depreciation. Remember, a 100,000-hour rating is not equivalent to lamp life rating. LED life is rated where it has reached 30 percent lumen depreciation. At 100,000 hours an LED would still be operating, but at a decreased lumen output.
16. Is there a warm-up time needed when switching on a LED luminaire?
No. LEDs do not have the long warm-up times, which many people find annoying about CFLs (compact fluorescent lamps). Instead, the light from LEDs shines at full brilliance as soon as the switch is turned on. Also cold temperatures do not affect the performance of LED luminaire.
17 . How mechanically durable is a LED luminaire?
Unlike other light bulbs that use fragile filaments (especially incandescent light bulbs) LEDs are vibration and shock resistant. While vibration or shock easily breaks the fragile filament in an incandescent bulb and the glass tubing of a fluorescent lamp, LEDs tolerate vibration exceptionally well because they do not use filaments. Energized components of the LED are well separated from the outer surface with high quality insulation. The electrodes are embedded in the bulb matrix and the driver electronics are encased in its shell. A layer of interface material between the LED and the heat sink ensures that no current can leak to the heat sink. This make LED luminaire a completely solid-state technology which are virtually indestructible under normal circumstances.
18. How accurate is the color reproduction of LED light?
Color Rendering Index or CRI is the calculated rendered color of an object. The higher the CRI (based upon a 0-100 scale), the more natural the colors appear. Natural outdoor light has a CRI of 100. White LEDs offer the industry’s highest CRI (80-90), making objects to be illuminated appear more natural and vibrant, which increases overall safety.
19. Can LEDs be dimmed?
The forward current is proportional to the light output of an LED over a large operating range, so dimming can be achieved with reductions in the forward current. Because LEDs can be rapidly switched on and off with no harmfull effects, dimming can be accomplished using a method called pulse width modulation. By adjusting the relative duration of the pulse and the time between pulses, the apparent intensity of the LED can be dimmed. This is done with direct digital control, which enables frequency high enough that LED appears to be continuosly lighted without flickering.
20. Does dimming LEDs decrease their lamp life?
It has been observed that when some fluorescent lighting systems are frequently dimmed, they might exhibit reliability and lamp life. This is not the case for LEDs. Life and light output degradation are determined largely by the junction temperature, with higher temperatures resulting in reduced life characteristics. Since dimming, either by reducing current or by pulse width modulation, results in lower overall junction temperatures, it will have no negative impact on LED life, it might even extend life.
21. What does the IP and IK rating means?
IK – protection against mechanical impacts
The European standard EN 62262 ( the equivalent of international standard IEC 62262:2002) relates to IK ratings. This is an international numeric classification for the degrees of protection provided by enclosures for electrical equipment against external mechanical impacts. It provides a means of specifying the capacity of an enclosure to protect its contents from external impacts.
EN 62262 specifies the way enclosures should be mounted when tests are carried out, the atmospheric conditions that should prevail, the number of impacts (5) and their (even) distribution, and the size, style, material, dimensions etc. of the various types of hammer designed to produce the energy levels required.
|Level of protection
|Protected against energy at the impact of 0.15J
|Drop of 200 g object from 7.5 cm height
|Protected against energy at the impact of 0.20J
|Drop of 200 g object from 10 cm height
|Protected against energy at the impact of 0.35J
|Drop of 200 g object from 17.5 cm height
|Protected against energy at the impact of 0.50J
|Drop of 200 g object from 25 cm height
|Protected against energy at the impact of 0.70J
|Drop of 200 g object from 35 cm height
|Protected against energy at the impact of 1.00J
|Drop of 500 g object from 20 cm height
|Protected against energy at the impact of 2.00J
|Drop of 500 g object from 40 cm height
|Protected against energy at the impact of 5.00J
|Drop of 1.7 kg object from 29.5 cm height
|Protected against energy at the impact of 10.00J
|Drop of 5 kg object from 20 cm height
|Protected against energy at the impact of 20.00J
|Drop of 5 kg object from 40 cm height
IP – Ingress Protection Rating
The IP Code (or International Protection Rating, also interpreted as Ingress Protection Rating) consists of the letters IP followed by two digits and an optional letter. As defined in international standard IEC 60529, it classifies the degrees of protection provided against the intrusion of solid objects (including body parts like hands and fingers), dust, accidental contact, and water in electrical enclosures The digits (characteristic numerals) indicate conformity with the conditions summarized in the tables below. Where there is no protection rating with regard to one of the criteria, the digit is replaced with the letter X.
IP First number – Protection against solid objects
|IP first number
|Protection level – solid objects
|No special protection
|Protected against solid objects up to 50 mm, e.g. accidental touch by persons hands.
|Protected against solid objects up to 12 mm, e.g. persons fingers.
|Protected against solid objects over 2.5 mm (tools and wires).
|Protected against solid objects over 1 mm (tools, wires, and small wires).
|Protected against dust limited ingress (no harmful deposit).
|Totally protected against dust and contact.
IP Second number – Protection against liquids
|IP second number
|Protection level – liquids
|Protection against vertically falling drops of water e.g. condensation.
|Protection against direct sprays of water up to 15o from the vertical.
|Protected against direct sprays of water up to 60o from the vertical.
|Protection against water sprayed from all directions – limited ingress permitted.
|Protected against low pressure jets of water from all directions – limited ingress.
|Protected against temporary flooding of water, power jets from all directions limited ingress permitted.
|Protected against the effect of immersion between 15 cm and 1 m.
|Protects against long periods of immersion under pressure.
22. Do LED luminaires contain any harmful substances?
No, LEDs contain no harmful substances. Mercury is not used in LEDs, frelieving you from the environmental hazards which are present with disposing of burnt-out fluorescent, metal halide, and high pressure sodium light bulbs.
23. Is there any infrared radiation coming out of LED luminaires?
White LEDs do not emit infrared radiation (no beam heat) so, the beam of light produced by a white LED does not contain any heat. This makes LEDs ideal for shallow ceiling downlighting and display lighting.
24. How is with ultraviolet radiation in LED luminaires?
White LEDs do not produce any ultraviolet (UV) light even though all other natural and artificial light sources do. This has many benefits:
• Limited Fabric Fading
When using white LED light fixtures, there will be minimal fading and deterioration of fabrics, documents, or artwork due to exposure to the white light from LEDs.
• Better for Fruits & Vegetables
Unlike light sources like metal halide, LEDs do not radiate high levels of UV rays. While it is common knowledge that heat can speed up food’s spoilage rate, it is lesser known that high UV levels can actually decrease the nutrient levels in food. Thus, using LEDs to light the produce in a super market, for example, may not only be energy efficient, it may also help the produce to maintain higher nutrient levels.
25. What is the importance of full cut off lights?
Full cut off lights minimize environmental light pollution and help save money that was being used to light up the sky. Reduction of ambient light levels in the sky makes the skies ‘night friendly’ allowing astronomers to observe heavenly bodies and minimizes the impact of anthropogenic lighting on the circadian rhythm of nocturnal animals and plants.
26. How much can I save with LSL® lights?
Savings while replacing inefficient old lamps with Aerolite LSL® LED lights vary depending on wattage and lifetime of currently installed lights. Since LSL® has a minimum lifetime of 60.000 hours (and can easily go up to 100.000 hours), has low wattage and requires almost no maintenance, total savings in electricity and maintenance can be up to 90% compared to old lights. All this can be achieved while improving illumination performance at the same time. Also CO2 emissions will be drastically reduced and considering the fact that LSL® is completely environmentally friendly, by deciding for Aerolite LSL® you will contribute to the protection of the environment.
Replacement of 30 pieces HPS lights to Aerolite LSL®30 lights
$37,260 total savings
38,235 kg total CO2 emission reduction
Replacement of 100 pieces HPS lights to Aerolite LSL®90 lights
$ 249,000 total savings
453.120 kg total CO2 emission reduction
Replacement of 500 pieces HMQ lights to Aerolite LSL®30 lights
$ 1,023,000 total savings
1,823,100 kg total CO2 emission reduction
Replacement of 1000 pieces HMQ lights to Aerolite LSL®90 lights
$ 10,290,000 total savings
27,696,000 kg total CO2 emission reduction
Replacement of 2000 pieces HMQ lights to Aerolite LSL®
$ 6,804,000 total savings
15,292,800 kg total CO2 emission reduction
Replacement of 200 pieces mercury lights to Terralite LCL®90 lights
$ 1,479,600 total savings
3,993,120 kg total CO2 emission reduction