LED’s sail – LED lighting for economical cruising
Lighting systems on modern cruise ships account for up to 25% of the total energy consumption which is not used for propulsion; this means that any reduction in electricity consumption for lighting leads to a positive impact on the operating costs. LED Linear, bluleu led solutions and Navalimpianti are already working with leading shipyards throughout Europe to develop efficient LED lighting solutions. Future LED generations will help to reduce energy consumption and costs in both interior and outdoor lighting, and thus contribute towards environmental protection.
In the shipping business, there are strict, demanding requirements when it comes to lighting. These include: Colour Rendering Index (CRI)I values of at least 80, light homogeneity, light outputs of 60 lm/W and higher, warm light colours of 3000K or less, and a long service life. Especially for outdoor lighting, high weather resistance is also required. In addition, easy assembly and replaceability as well as standard sizes are required, in order to meet relevant standards and regulations.
High colour homogeneity is extremely important, particularly for the illumination of long axes of vision, for example along the railing, or of large rooms with more than 2,000 built-in lights and is consequently crucial for lighting manufacturers such as LED Linear, bluleu led solutions and Navalimpianti. A deviation of only a few Kelvin is already perceived by the human eye as a colour difference which, particularly in area or strip lighting, is not acceptable. When selecting the LED components in this case, it is important to have a tight binning within the small Mac Adam 4-step ellipses and a binning structure, which complies with the latest standards (ANSI).
Light quality and light efficiency are two sides of the same coin: For customers, high CRI values together with high efficiency and a warm colour temperature are fundamental criteria for the selection of LEDs: this is a challenge for LED manufacturers, since high CRI values, combined with a warm colour temperature, reduce the efficiency of the lamps.
The service life of LEDs is another important factor for customers. Total failures are extremely rare in the case of LEDs, in contrast to conventional light bulbs, and their light intensity decreases rather slowly. The service life of LEDs is therefore defined as the time it takes for the original luminous flux to decrease up to 70 percent. This depends on the operating and ambient temperature and corresponds to around 50,000 operating hours at room temperature. Therefore, optimum heat management is a vital feature of LED lights. An important role is thus played by a good thermal connection through a favourable pad design and a low thermal resistance of the LED, as well as a high quality package design, in order to guarantee good thermal and mechanical endurance. Good heat management ensures that service intervals for difficult to access lighting solutions are drastically extended, thus saving costs. For this reason, according to the lighting solution specifications of LED Linear, the junction temperature of the LED at an ambient temperature of 45°C must not exceed 95°C, which guarantees a service life of the lamps of 50,000 hours.
LED Linear, bluleu led solutions and the Meyer shipyard:
With the "Celebrity Equinox", in collaboration with bluleu led solutions and LED Linear, the Meyer shipyard has developed and built a luxury ship which is particularly environmentally friendly. Energy-efficient systems such as a photovoltaic system and an energy-efficient LED lighting system from LED Linear lead to significant energy savings. With innovative LED lighting solutions from LED Linear and bluleu led solutions, it is possible to save up to 30% in weight, which means the overall weight can be reduced by up to eight tonnes. For a cruise ship with a capacity of 2,500 passengers and 50,000 light sources, the use of LED solutions can allow a reduction of CO2 emissions by up to 3,000 tons per year and annual cost savings of up to €200,000. Lighting experts estimate that the savings potential is as high as 20% of current consumption.
Bluleu led solutions and LED Linear supplied the "Celebrity Equinox" with more than 1,200 metres of water-tight LED strips of the product series VarioLED Flex ATON IP67 and VarioLED Flex Venus, that were used for the railing lighting as well as complete ready-to-plug systems for installation in stairways.
The encapsulated luminaires with protection classes up to IP 68 are extremely weather resistant and protected against yellowing and salt water thanks to high-quality sealing. The illuminants used by LED Linear also include SAE and Double Dome LEDs from Sharp, mounted on flexible circuit boards. They are available in a roll or sealed tapes, are easy to install and can be laid in any shape. They therefore offer many opportunities for the creation of innovative shapes and functions, which are not possible with the currently available standard lamps. During construction of the "Celebrity Equinox" they won approval due to their compact design and their extreme insensitivity to even the smallest dust particles and moisture. With a power consumption of just 7.6 watts per metre at a supply voltage of 24V, they achieve a luminous efficiency of 75 lm/W for a length of up to 7.5 metres.
In general, the high-quality linear LED lighting solutions are based on a thermally enhanced, flexible printed circuit board technology. With lengths of up to ten metres, products offer a luminous flux of 3500 lm per metre and a colour rendering index of up to 92. The colour temperatures range from 2700 to 6300K at 100 lm/W. They therefore provide a cost-efficient and variable modular system for the individual design of linear LED lighting systems. Through the use of high quality LEDs, LED Linear products reach a service life of 50,000 hours for a guaranteed period of three years.
Navalimpianti and Powergiant 2:
In order to meet all the stringent requirements of the shipping industry, for interior lighting, Navalimpianti has developed the "Powergiant 2" range of recessed luminaires based on a Sharp Zenigata LED. They can directly replace conventional lighting systems and thus provide an enormous savings potential also for existing ships. A typical cruise ship for 2,800 passengers weighing 92,000 tons, with 16 decks and 1,150 cabins is illuminated in public areas (e.g. lobby, restaurant, etc.) with just under 8,000 halogen lamps. About one fifth of these in the cabins and corridors have an output of 35 W, whilst the output of most of the rest lies in the region of 50 W. Overall, the lighting of a ship of this type has a power output requirement of around 370 kW for the public areas alone. If one were to replace all traditional halogen solutions with Powergiant 2 recessed lights, the power consumption of the ship lighting could be reduced by almost 300 kW. With an operating time of between 12 – 24 hours per day depending on the application, about 7,100 kWh of energy and 1.5 tonnes of fuel could be saved every day, resulting in a total daily saving of around €550.
If one also considers the service life of 50,000 hours, further savings are possible due to lower maintenance costs. With an average use of 10 hours a day, a Powergiant 2 is lit for over eight years, whilst the service life of a high-quality halogen lamp is only about 6 to 7 months. Usually the service life of halogen lamps is even lower due to the vibrations when the engines are running, whilst this strain does not affect LED technology in the slightest. In addition, at the end of its service life a Powergiant still has at least 70% of its initial light power output with an almost constant light quality. The dimmable Powergiant 2 LED recessed luminaires ensure a very natural colour rendition of illuminated objects with a CRI value of 80. The light output is 60 lm/W with a power consumption of just 9 W.
Thanks to the low power consumption and the lack of UV radiation, the Powergiant lamps have a very low surface temperature which improves the safety factor as, amongst other things, the risk of fire in cabins or in other areas of the ship is therefore drastically reduced. Powergiant lights are dimmable and fully compatible with the Helvar Lighting dimming system or other IGBT phase-cut dimmers, which are often used on ships. As a result, Powergiant products can replace existing halogen solutions without the need for extensive changes to the cabling and electric circuit. For the Powergiant models, Navalimpianti offers several optical solutions (for a narrow, medium and wide beam), which can be changed as required by lighting designers and architects depending on the particular application.
The high demands placed by shipbuilders on their lighting suppliers explain why companies such as LED Linear and Navalimpianti attach great importance to quality in the selection of illuminants, and therefore rely on Sharp as a partner.
Homogeneity is one of the essential characteristics of LED Linear and Navalimpianti products: at the same time it represents a great challenge in the production of LEDs. It is a matter of achieving a defined colour temperature which is as uniform as possible in each component, in all production batches. Many manufacturers accept a certain fluctuation margin in LED production and subsequently select the LEDs in accordance with defined deviations from the original colour. In this so-called binning process, the exact colour temperature of the LED is ultimately defined not only by the nominal value, but also the binning rank of the LEDs. Sharp, on the other hand, has already optimised the manufacturing process of its LED arrays to the extent that the fluctuation margin of the colour temperature between individual LEDs is so small that it cannot be perceived by the human eye. There is therefore no need for a selection following production. With Sharp, the user can be sure that LEDs from one series can hardly be distinguished from one another optically, even if they come from different production batches. Even if reordered at a later date, the new LEDs have the same defined colour tone as the first ones used; this is because LEDs from Sharp are also distinguished by a high consistency in their optical parameters and particularly of the colour temperature over the entire service life of 50,000 hours*.
A second important selection criterion is the Colour Rendering Index, This ensures high colour fastness and accuracy of detail. With different mixtures of red and green phosphor, white light LEDs from Sharp reach very high CRI values. All LED components from Sharp, for all colour temperatures, have a CRI value of at least 80; this is a significant qualitative leap, especially in the case of warm-white light LEDs, the CRI values of which were in the region of 60 – 70 until now. The high colour rendering modules of the Zenigata and Mega Zenigata series reach a CRI value of as high as 94. In connection with a good luminous efficiency, the characteristics of the new HCR LEDs from Sharp almost match those of conventional fluorescent tubes in terms of efficiency, colour temperature and CRI. They therefore meet the requirements of the international Energy Star Program, but provide a much longer service life with 50,000 operating hours*.
The third important criterion for shipbuilders is a long service life which, in the case of LEDs, depends in the first instance on how efficiently the heat can be dissipated: As a LED substrate, Sharp therefore uses a high-quality ceramic plate with silicon sealing instead of conventional plastic materials. This design allows for efficient and homogeneous heat dissipation as well as good thermal and mechanical resistance. In so doing, it helps to keep the required cooling element small, but also to guarantee the service life of 50,000 hours. These concerns were a further reason why LED Linear and Navalimpianti chose Sharp as a strategic partner for the supply of LED components.
Amongst others, LED Linear uses the Sharp LEDs Double Dome and SAE series for its systems. These are hardly bigger than a match head. With their construction measuring just 2.8 x 2.8 x 1.9 and 3.2 x 2.8 x 1.9 mm, they offer a high level of brightness. For its recessed luminaires, on the other hand, Navalimpianti uses multi-chip LEDs from the Zenigata and Mini Zenigata series.
They too are included in the field of LED arrays for compact size and easy assembly. For manufacturers such as LED Linear as well as designers, the compact construction of LEDs means totally new freedom in the creation of lamps. This is a benefit not only for shipbuilders. The integration, for example, in light gaps of architectural lighting, in furniture, ceilings and as reading lamps in a car’s roofliner, etc. is also made much easier by them.
Conclusion
LEDs for lighting solutions are gaining increasing importance also in the shipping industry. The main reasons for this lie in the energy saving potential and the long service life, which contributes substantially towards reducing ongoing operating costs. After all, the conventional lighting systems consume about 25% of the energy which is then not used for propulsion, as the power consumption of conventional ship lighting is about six times higher than that of advanced LED lighting systems, such as those offered by LED Linear, bluleu led solutions and Navalimpianti.
However, the application of such systems in ship building places very high demands on the quality of lamps and bulbs. These are firstly due to the harsh pressures and weather conditions at sea and on the other – as with other architectural and decorative lighting applications – to the high demands on the homogeneity of the colour temperature and colour fastness for the entire service life of the lamps. As suppliers of shipyards, amongst others, lighting manufacturers such as LED Linear, bluleu led solutions and Navalimpianti attach great importance to quality in the selection of illuminants, in order to meet the expectations of their customers. With its broad portfolio of over 120 high quality LED components, Sharp is the ideal partner for manufacturers of LED lighting solutions for demanding applications such as shipbuilding.
About the author
Uwe Hock is Manager Lighting Business for Sharp Microelectronics Europe.
(*) at a substrate temperature of up to 80°C, depending on module
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