The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Liisa Halonen - One of the best experts on this subject based on the ideXlab platform.
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Life cycle cost comparison of high-pressure sodium and light-emitting diode Luminaires in street lighting
The International Journal of Life Cycle Assessment, 2016Co-Authors: Leena Tähkämö, Rami-samuli Räsänen, Liisa HalonenAbstract:Purpose Cities and municipalities are facing a great challenge in 2015 when the widely used high-pressure mercury lamps are banned from the European Union market. This results to approximately 18 million lamps to be changed to other light source technologies suitable for outdoor lighting. The most probable replacement technologies are high-pressure sodium and light-emitting diode Luminaires. The article provides economic information for the cities and municipalities to use when making the decision on the choice of technology. Methods A life cycle cost analysis was conducted for the high-pressure sodium and light-emitting diode Luminaires including the investment costs, operating costs and residual value over 30-year time frame. The investment costs included the purchase prices of all parts, freight and installation costs. The operating costs accounted for the energy and maintenance costs, and the residual value was calculated using the 25 % estimate of the initial purchase price. The approach of the calculation considered only the Luminaires to be installed; the scope of the study excluded the previous installations, which may contain any light source technology or be inexistent. The analysis excluded the poles, wiring and other infrastructure. A sensitivity analysis additionally studied six scenarios, in which relevant calculation parameters were changed. Results and discussion The life cycle cost analysis of the two road lighting luminaire technologies showed that the HPS luminaire was normally a more economical solution compared to the light-emitting diode (LED) luminaire. The total life cycle costs of the HPS luminaire were 45 % lower than those of the LED luminaire per kilometre. However, the scenarios in the sensitivity analysis indicated that there were circumstances where the cost-efficiency of the LED luminaire was particularly improved. In order for the LED technology to become fully competitive against the HPS technology, several scenarios have to take place simultaneously. The life cycle costs of the LED luminaire were reduced compared to the HPS luminaire by increased electricity price, exclusion of spot replacements, reduced purchase price and modularity of the LED luminaire. Conclusions Despite the greater luminous efficacy, the LED luminaire was found to have greater life cycle costs compared to the HPS luminaire. However, the LED technology is expected to become more economical in the future due to the development in luminous efficacy, improved product quality, reduction in the purchase price and the enhanced competition in the LED segment. Despite the unfavourable cost structure, the LED technology offers other benefits, such as lighting controls and colour characteristics.
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Life cycle assessment of road lighting Luminaires - Comparison of light-emitting diode and high-pressure sodium technologies
Journal of Cleaner Production, 2015Co-Authors: Leena Tähkämö, Liisa HalonenAbstract:Abstract A life cycle assessment compared the environmental impacts of two typical road lighting technologies: high-pressure sodium (HPS) and light-emitting diode (LED) Luminaires. The environmental impacts of manufacturing, use and end-of-life of the Luminaires were studied with a special regard to the functional unit. The results confirmed that the use caused the majority of the environmental impacts: 96% in HPS and 87% in LED luminaire over 30 years of operation, while manufacturing accounted for 4% and 13%, and end-of-life less than 1%, respectively. In the comparison per luminaire or per lumenhour, the LED luminaire caused 26% or 17% lower average environmental impacts than the HPS luminaire, respectively. However, a luminaire or an amount of lumenhours does not describe the actual function of the luminaire. When the Luminaires were compared on the basis of a kilometre of lit road, the difference between the LED and HPS technologies was only 3% on average. This illustrates the importance of the functional unit. In addition, the development of the LED technology will decrease its environmental impacts and make it clearly environmentally favourable: with the estimated luminous efficacy development in 2020, the environmental impacts of the LED luminaire per kilometre of lit road were estimated to be 41% lower compared to the HPS technology.
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Life cycle cost analysis of three renewed street lighting installations in Finland
The International Journal of Life Cycle Assessment, 2012Co-Authors: Leena Tähkämö, Anne Ylinen, Marjukka Puolakka, Liisa HalonenAbstract:Purpose Outdoor lighting is facing major changes due to the EU legislation on ecodesign of energy-related products, such as the ban of high-pressure mercury (HPM) lamps widely used in outdoor lighting. This article presents life cycle costs (LCC) of three examples of replacing HPM lamps in street lighting in Finland. The purpose of the article is to assess how the development of light-emitting diode (LED) technology affects LCCs and how the division of LCCs differentiates in the cases. Methods Two of the cases change from HPM lamps to high-pressure sodium (HPS) lamps. In the third one, HPM lamps are replaced by LED Luminaires. LED technology predictions of price and luminous efficacy are included in different scenarios. The calculations consider investment and operating costs and residual value. Results and discussion Each replacement reduces the energy costs approximately by half compared to the original HPM lamp Luminaires. Energy costs dominate the LCCs of the HPS lamp installations while investment cost is the dominating one in LED luminaire case. The changes from HPM to HPS technology have payback times lower than 9 years, while changing to LED Luminaires is not economic. However, the electricity price is low in this case. The payback times of LED installations can be as low as 6 years if the Luminaires are installed in 2015 and an average electricity price is used. Conclusions The LCCs of real-life case studies cannot be directly compared, since their luminous properties vary. There is a need for a method for including luminous properties in LCC calculations.
Leena Tähkämö - One of the best experts on this subject based on the ideXlab platform.
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Life cycle cost comparison of high-pressure sodium and light-emitting diode Luminaires in street lighting
The International Journal of Life Cycle Assessment, 2016Co-Authors: Leena Tähkämö, Rami-samuli Räsänen, Liisa HalonenAbstract:Purpose Cities and municipalities are facing a great challenge in 2015 when the widely used high-pressure mercury lamps are banned from the European Union market. This results to approximately 18 million lamps to be changed to other light source technologies suitable for outdoor lighting. The most probable replacement technologies are high-pressure sodium and light-emitting diode Luminaires. The article provides economic information for the cities and municipalities to use when making the decision on the choice of technology. Methods A life cycle cost analysis was conducted for the high-pressure sodium and light-emitting diode Luminaires including the investment costs, operating costs and residual value over 30-year time frame. The investment costs included the purchase prices of all parts, freight and installation costs. The operating costs accounted for the energy and maintenance costs, and the residual value was calculated using the 25 % estimate of the initial purchase price. The approach of the calculation considered only the Luminaires to be installed; the scope of the study excluded the previous installations, which may contain any light source technology or be inexistent. The analysis excluded the poles, wiring and other infrastructure. A sensitivity analysis additionally studied six scenarios, in which relevant calculation parameters were changed. Results and discussion The life cycle cost analysis of the two road lighting luminaire technologies showed that the HPS luminaire was normally a more economical solution compared to the light-emitting diode (LED) luminaire. The total life cycle costs of the HPS luminaire were 45 % lower than those of the LED luminaire per kilometre. However, the scenarios in the sensitivity analysis indicated that there were circumstances where the cost-efficiency of the LED luminaire was particularly improved. In order for the LED technology to become fully competitive against the HPS technology, several scenarios have to take place simultaneously. The life cycle costs of the LED luminaire were reduced compared to the HPS luminaire by increased electricity price, exclusion of spot replacements, reduced purchase price and modularity of the LED luminaire. Conclusions Despite the greater luminous efficacy, the LED luminaire was found to have greater life cycle costs compared to the HPS luminaire. However, the LED technology is expected to become more economical in the future due to the development in luminous efficacy, improved product quality, reduction in the purchase price and the enhanced competition in the LED segment. Despite the unfavourable cost structure, the LED technology offers other benefits, such as lighting controls and colour characteristics.
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Life cycle assessment of road lighting Luminaires - Comparison of light-emitting diode and high-pressure sodium technologies
Journal of Cleaner Production, 2015Co-Authors: Leena Tähkämö, Liisa HalonenAbstract:Abstract A life cycle assessment compared the environmental impacts of two typical road lighting technologies: high-pressure sodium (HPS) and light-emitting diode (LED) Luminaires. The environmental impacts of manufacturing, use and end-of-life of the Luminaires were studied with a special regard to the functional unit. The results confirmed that the use caused the majority of the environmental impacts: 96% in HPS and 87% in LED luminaire over 30 years of operation, while manufacturing accounted for 4% and 13%, and end-of-life less than 1%, respectively. In the comparison per luminaire or per lumenhour, the LED luminaire caused 26% or 17% lower average environmental impacts than the HPS luminaire, respectively. However, a luminaire or an amount of lumenhours does not describe the actual function of the luminaire. When the Luminaires were compared on the basis of a kilometre of lit road, the difference between the LED and HPS technologies was only 3% on average. This illustrates the importance of the functional unit. In addition, the development of the LED technology will decrease its environmental impacts and make it clearly environmentally favourable: with the estimated luminous efficacy development in 2020, the environmental impacts of the LED luminaire per kilometre of lit road were estimated to be 41% lower compared to the HPS technology.
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Life cycle assessment of light-emitting diode downlight luminaire—a case study
The International Journal of Life Cycle Assessment, 2013Co-Authors: Leena Tähkämö, Manuel Bazzana, Pierre Ravel, Francis Grannec, Christophe Martinsons, Georges ZissisAbstract:Purpose Light-emitting diode (LED) technology is increasingly being used for general lighting. Thus, it is timely to study the environmental impacts of LED products. No life cycle assessments (LCA) of recessed LED downlight Luminaires exist in the literature, and only a few assessments of any type of LED light source (component, lamp and luminaire) are available. Methods The LCA of a recessed LED downlight luminaire was conducted by using the data from the luminaire manufacturer, laboratory measurements, industry experts and literature. The assessment was conducted using SimaPro LCA software. EcoInvent and European Reference Life Cycle Database were used as the databases. The LCA included a range of environmental impacts in order to obtain a broad overview. The functional unit of the LCA was one luminaire used for 50,000 h. In addition, the sensitivity of the environmental impacts to the life was studied by assessing the LED downlight luminaire of 36,000 h and 15,000 h useful life and to the used energy sources by calculating the environmental impacts using two average energy mixes: French and European. Results and discussion The environmental impacts of the LED luminaire were mostly dominated by the energy consumption of the use. However, manufacturing caused approximately 23 % of the environmental impacts, on average. The environmental impacts of manufacturing were mainly due to the driver, LED array and aluminium parts. The installation, transport and end of life had nearly no effect on the total life cycle impacts, except for the end of life in hazardous waste. The life cycle environmental impacts were found to be sensitive to the life of the luminaire. The change from the French to the European average energy mix in use resulted to an even clearer dominance of the use stage. Conclusions The case study showed that the environmental impacts of the LED downlight luminaire were dominated by the use-stage energy consumption, especially in the case of the European energy mix in use. Luminous efficacy is, thus, a relatively appropriate environmental indicator of the luminaire. As LED technology possesses generally higher luminous efficacy compared to conventional ones, the LED luminaire is considered to represent an environmentally friendly lighting technology. However, data gaps exist in the data in LED product manufacturing and its environmental impacts. The environmental impacts of different LED products need to be analysed in order to be able to precisely compare the LED technology to the conventional lighting technologies.
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Life cycle cost analysis of three renewed street lighting installations in Finland
The International Journal of Life Cycle Assessment, 2012Co-Authors: Leena Tähkämö, Anne Ylinen, Marjukka Puolakka, Liisa HalonenAbstract:Purpose Outdoor lighting is facing major changes due to the EU legislation on ecodesign of energy-related products, such as the ban of high-pressure mercury (HPM) lamps widely used in outdoor lighting. This article presents life cycle costs (LCC) of three examples of replacing HPM lamps in street lighting in Finland. The purpose of the article is to assess how the development of light-emitting diode (LED) technology affects LCCs and how the division of LCCs differentiates in the cases. Methods Two of the cases change from HPM lamps to high-pressure sodium (HPS) lamps. In the third one, HPM lamps are replaced by LED Luminaires. LED technology predictions of price and luminous efficacy are included in different scenarios. The calculations consider investment and operating costs and residual value. Results and discussion Each replacement reduces the energy costs approximately by half compared to the original HPM lamp Luminaires. Energy costs dominate the LCCs of the HPS lamp installations while investment cost is the dominating one in LED luminaire case. The changes from HPM to HPS technology have payback times lower than 9 years, while changing to LED Luminaires is not economic. However, the electricity price is low in this case. The payback times of LED installations can be as low as 6 years if the Luminaires are installed in 2015 and an average electricity price is used. Conclusions The LCCs of real-life case studies cannot be directly compared, since their luminous properties vary. There is a need for a method for including luminous properties in LCC calculations.
Atthapol Ngaopitakkul - One of the best experts on this subject based on the ideXlab platform.
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optimisation of lighting quality and energy efficiency of led Luminaires in roadway lighting systems on different road surfaces
Sustainable Cities and Society, 2018Co-Authors: Suntiti Yoomak, Atthapol NgaopitakkulAbstract:Abstract Lighting quality plays an important role in determining the visual performance and visual comfort of the road user, which help keep driver alert. Lighting quality depends on various factors, such as mounting height, luminaire spacing, Luminaires, overhang, boom angle, and road surface properties. The light that reflects from the road surface enters the eyes of the road user, and makes the road visible. However, prevailing conditions on the roadway determine the reflection properties of the road surface. This paper presents the analysis of lighting quality in different road surface conditions using the DIALux software. Dry and wet road surfaces are used to study lighting quality following the classifications of the International Commission on Illumination (CIE), where the lighting qualities of high-pressure sodium (HPS) and light-emitting diode (LED) Luminaires are compared, based on a roadway without a traffic island. In addition, it presents the design of a roadway lighting system with optimised LED Luminaires, by adjusting pole spacing and mounting height, ensuring the best installation in each classification of road surface. Thereafter, energy evaluations of different input powers of LED Luminaires are discussed and compared with the HPS luminaire. Results indicate that the HPS luminaire can provide better average illuminance and average luminance values than LED Luminaires, resulting in positive visual performance. However, LED Luminaires can achieve better overall visual and comfort performances, including energy saving, due to their light distribution efficiency. For lighting quality in different road surface conditions, the wetter the road surface, the higher the lighting quality; because wet road surfaces cause alternating bright and dark areas on the road. This results in increased average luminance of the surface, and decreased longitudinal uniformity. Moreover, road surfaces with high average luminance coefficient, Q0, can accommodate larger pole spacing, reducing energy consumption. Using LED Luminaires with lower or higher input power than the optimal power, however, result in higher energy consumption.
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comparative study of lighting quality and power quality for led and hps Luminaires in a roadway lighting system
Energy and Buildings, 2018Co-Authors: Suntiti Yoomak, Atthapol Ngaopitakkul, Chaiyan Jettanasen, Sulee Bunjongjit, Monthol LeelajindakrairerkAbstract:Abstract Roadway lighting was one of the earliest applications for electric lighting technologies. Well-designed roadway lighting offers many benefits and aids the visual tasks of drivers and pedestrians. Currently, the trend of energy management for exterior general lighting has increased in several cities. Generally, high-pressure sodium (HPS) lamps have been the standard throughout Thailand since the 1980s, but the use of HPS lamps has driven high energy consumption. To conserve energy, light emitting diode (LED) street lighting has quickly become a new trend. The primary objective of this paper is to deliver an initial and in-depth assessment of LED technology for roadway lighting applications. This analysis focuses on the performance of LED Luminaires compared with the existing standard of HPS cobra-head Luminaires in terms of lighting quality, energy savings, power quality, and investment. The analysis is conducted via three components. First, simulation of the roadway lighting quality is performed using the DIALux programme to evaluate and compare with the standard of Thailand. Second, an experimental setup is used to evaluate the energy savings and power quality for cases with and without solar power. Third, the discounted payback period (DPP) criterion and internal rate of return (IRR) are applied to evaluate the investment scenarios. The obtained results conclude that the LED luminaire performs better than the HPS luminaire in terms of power quality and energy savings (energy-efficient index reduction of approximately 40% over the HPS luminaire), which indicates that the utility benefits from use of LED Luminaires. However, although the lighting quality results for LED luminaire have values fairly close to that of the standard, the lighting quality should be improved in terms of uniformity. The results obtained from this analysis are expected to help to improve the roadway lighting standard of Thailand in the future.
Suntiti Yoomak - One of the best experts on this subject based on the ideXlab platform.
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optimisation of lighting quality and energy efficiency of led Luminaires in roadway lighting systems on different road surfaces
Sustainable Cities and Society, 2018Co-Authors: Suntiti Yoomak, Atthapol NgaopitakkulAbstract:Abstract Lighting quality plays an important role in determining the visual performance and visual comfort of the road user, which help keep driver alert. Lighting quality depends on various factors, such as mounting height, luminaire spacing, Luminaires, overhang, boom angle, and road surface properties. The light that reflects from the road surface enters the eyes of the road user, and makes the road visible. However, prevailing conditions on the roadway determine the reflection properties of the road surface. This paper presents the analysis of lighting quality in different road surface conditions using the DIALux software. Dry and wet road surfaces are used to study lighting quality following the classifications of the International Commission on Illumination (CIE), where the lighting qualities of high-pressure sodium (HPS) and light-emitting diode (LED) Luminaires are compared, based on a roadway without a traffic island. In addition, it presents the design of a roadway lighting system with optimised LED Luminaires, by adjusting pole spacing and mounting height, ensuring the best installation in each classification of road surface. Thereafter, energy evaluations of different input powers of LED Luminaires are discussed and compared with the HPS luminaire. Results indicate that the HPS luminaire can provide better average illuminance and average luminance values than LED Luminaires, resulting in positive visual performance. However, LED Luminaires can achieve better overall visual and comfort performances, including energy saving, due to their light distribution efficiency. For lighting quality in different road surface conditions, the wetter the road surface, the higher the lighting quality; because wet road surfaces cause alternating bright and dark areas on the road. This results in increased average luminance of the surface, and decreased longitudinal uniformity. Moreover, road surfaces with high average luminance coefficient, Q0, can accommodate larger pole spacing, reducing energy consumption. Using LED Luminaires with lower or higher input power than the optimal power, however, result in higher energy consumption.
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comparative study of lighting quality and power quality for led and hps Luminaires in a roadway lighting system
Energy and Buildings, 2018Co-Authors: Suntiti Yoomak, Atthapol Ngaopitakkul, Chaiyan Jettanasen, Sulee Bunjongjit, Monthol LeelajindakrairerkAbstract:Abstract Roadway lighting was one of the earliest applications for electric lighting technologies. Well-designed roadway lighting offers many benefits and aids the visual tasks of drivers and pedestrians. Currently, the trend of energy management for exterior general lighting has increased in several cities. Generally, high-pressure sodium (HPS) lamps have been the standard throughout Thailand since the 1980s, but the use of HPS lamps has driven high energy consumption. To conserve energy, light emitting diode (LED) street lighting has quickly become a new trend. The primary objective of this paper is to deliver an initial and in-depth assessment of LED technology for roadway lighting applications. This analysis focuses on the performance of LED Luminaires compared with the existing standard of HPS cobra-head Luminaires in terms of lighting quality, energy savings, power quality, and investment. The analysis is conducted via three components. First, simulation of the roadway lighting quality is performed using the DIALux programme to evaluate and compare with the standard of Thailand. Second, an experimental setup is used to evaluate the energy savings and power quality for cases with and without solar power. Third, the discounted payback period (DPP) criterion and internal rate of return (IRR) are applied to evaluate the investment scenarios. The obtained results conclude that the LED luminaire performs better than the HPS luminaire in terms of power quality and energy savings (energy-efficient index reduction of approximately 40% over the HPS luminaire), which indicates that the utility benefits from use of LED Luminaires. However, although the lighting quality results for LED luminaire have values fairly close to that of the standard, the lighting quality should be improved in terms of uniformity. The results obtained from this analysis are expected to help to improve the roadway lighting standard of Thailand in the future.
G. Q. Zhang - One of the best experts on this subject based on the ideXlab platform.
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an accelerated test method of luminous flux depreciation for led Luminaires and lamps
Reliability Engineering & System Safety, 2016Co-Authors: Cheng Qian, Cadmus Yuan, G. Q. ZhangAbstract:Abstract Light Emitting Diode (LED) Luminaires and lamps are energy-saving and environmental friendly alternatives to traditional lighting products. However, current luminous flux depreciation test at luminaire and lamp level requires a minimum of 6000 h testing, which is even longer than the product development cycle time. This paper develops an accelerated test method for luminous flux depreciation to reduce the test time within 2000 h at an elevated temperature. The method is based on lumen maintenance boundary curve, obtained from a collection of LED source lumen depreciation data, known as LM-80 data. The exponential decay model and Arrhenius acceleration relationship are used to determine the new threshold of lumen maintenance and acceleration factor. The proposed method has been verified by a number of simulation studies and experimental data for a wide range of LED luminaire and lamp types from both internal and external experiments. The qualification results obtained by the accelerated test method agree well with traditional 6000 h tests.
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a novel hybrid method for reliability prediction of high power led Luminaires
International Conference on Thermal Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, 2013Co-Authors: Miao Cai, K M Tian, Wenbin Chen, H Huang, H Y Tang, L L Liang, Daoguo Yang, Xuejun Fan, G. Q. ZhangAbstract:High power light-emitting diode (LED) has gained more and more applications because LED has many advantages over traditional light sources. However, it is extremely time-consuming and complicated to evaluate the LED Luminaires reliability, in particular, the luminous degradation. In this work, a novel hybrid method, which combines the thermal modeling and temperature measurement, is proposed to estimate the junction temperature of high-power LEDs at system level, and therefore predict the lifetime of LED luminaries based on the known LM-80 data. First, a reference point at a luminaire system is selected to measure the temperature in the operating mode. Secondly, thermal modeling is performed to predict the reliable relationship between the junction temperature and the temperature of reference point (measuring point). Finally, the relationship between lifetime and junction temperature provided by the known LM-80 database is applied to estimate the LED luminaire's lifetime. To validate the predicted junction temperature, the thermal measuring experiments combined with the thermal tester T3ster are also implemented in this paper. It is found that, after a luminaire operates to a steady situation, the temperature difference between the reference point and the junction point reaches a constant, which indicates the thermal resistance between them can be simplified as a stable value. Therefore, the junction temperature of a luminaire can be obtained based on the temperature measurement of a measuring point and the thermal modeling. The lifetime predicted with the proposed method meets closely the lifetime estimated by vendor. The proposed method is expected to be very useful in future LED luminaire qualification test specification, instead of running lumen maintenance test to extrapolate the lifetime.
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multi physics simulation and reliability analysis for led Luminaires under step stress accelerated degradation test
International Conference on Thermal Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, 2012Co-Authors: Hongyu Tang, G. Q. Zhang, Miao Cai, Daoguo Yang, Fengze Hou, Zaifu CuiAbstract:In this paper, the 3D model of a LED luminaire is built using the software Pro/Engineer and then the model is transferred to ANSYS Workbench platform where the LED luminaire under the temperature and humidity conditions during step stress accelerated degradation test (SSADT) is simulated. The simulation results of temperature distribution, humidity distribution and stress distribution of the model at three levels of temperature (45°C, 65°C, 85°C) and 60% RH (Relative Humidity) are acquired using multi-physics approach. In the post-processing of temperature data, combining Yamaoshi?s optical power empirial formula of LED degradation with the junction temperature in simulation, the optical decay curves at each stage of the test are obtained. Then, the long-term life test (LTLT) at room temperature (25°C) and SSADT at three levels of temperature are performed to illustrate the validity of simulation. The lumen maintenance of 3 LED Luminaires by LTLT and 5 samples by SSADT are analyzed to evaluate the luminous flux, optical decay rate and reliability under different working and ambient conditions. Finally, a comparison is made between the results of experiment and simulation. It is shown that the simulation results agree well with optical decay curves from the test, which indicates that the method can be used to predict the optical decay of LED Luminaires.
