Optimal Roof Coverage and Identification of Potential Roof Problems in Underground Coal Mines Using LED Lighting

The popularity and implementation of light emitting diode (LED) lighting have increased drastically over recent years into both residential and industrial applications. However, due to MSHA permissibility requirements, LED lighting is not currently being fully utilized in underground coal mining. While previous research has focused on examining the benefits that LED lighting possesses over other common light sources, very few have been done to find the optimum configuration to illuminate underground excavations better for the safety of the miners. In this research, multiple experiments were conducted to evaluate the potential impacts LED lighting can have on underground mine safety. The optimal light setup that provided the most roof coverage was found to be between 5 and 7 feet of separation, which is similar to what is usually used on roof bolting machines. It was also determined that LED lighting performs well in terms of discontinuity identification compared to what is commonly used in underground coal mining. The results of this research will serve as a design parameter for lighting manufacturers to use. These tests were done to simulate possible lighting locations on a roof bolting machine, but the results can be employed for other underground equipment as well

Effect of mechanical vibrations on light emitting diode luminaires

In this work, a LED and two types of Compact fluorescent lamps were investigated for the intensity variation due to mechanical vibrations in the range of 0 to 30 HZ. In general, subjecting the lamps to 24-hour vibration affects the total intensity percentage variations of peak intensities after vibrations is in the range of -25 to +15% compared to those of no vibrations for the light emitting diode luminaires. For the case of compact fluorescent lamps (Nuvue) the variations are in range from +10 to +35%, whereas for the Compact fluorescent lamps (Ecosmart) the intensity peaks range from -10 to +10%. Continuous vibration measurements at varying vibrational frequencies (measurements at each frequency for every 10 minutes) show that in the case of LED luminaires, there is no consistency of intensity peaks in case of light emitting diodes, i.e. there is an increase and decrease in intensities, whereas in the case of both compact fluorescent bulbs, there is an increase in intensity at the wavelength of 546.78nm (wavelength of maximum human sensitivity) which reaches a maximum at around 25Hz. Intensity variation effects due to vibration are attributed to the dropping off loose phosphor coatings in the inside wall of the glass enclosures. This effect is more pronounced in CFLs compared to LED luminaires due to the difference in the way the phosphor is coated/sandwiched

Accelerating the deployment of Solid State Lighting (SSL) in Europe

Solid State Lighting, in particular the use of LEDs and OLEDs for general lighting, is a promising technology with high growth potential in Europe. The path for the development of SSL in Europe is sketched out in the Green Paper on SSL of the European Commission. The current study supports the direction taken in the green paper towards deployment of SSL. This paper sketches the lighting consumptions and various applications of SSL, from fully-mature applications till the general lighting sector when mass adoption is expected from 2015, first in the retrofit market then in the new lighting fixtures and luminaires. It focuses on the strengths and weaknesses of the European market for SSL. Distinction can be made between the outdoor lighting sector, where LEDs are more present, and indoor lighting, where the growth rate is still low. The LED industry is rather fragmented. It is usually divided into five segments: materials, equipment, finished lamps and components, luminaires and systems, and finally lighting services and solutions. One of the vulnerability areas is the fact Europe is dependent from China for a variety of semiconductor materials, including various rare earth elements (REE), that are used in the production of LEDs. The European manufacturing base is strong in the downstream segments of the value chain close to the application (40%) but it is weaker in the upstream segments (LED packaging, chips, wafers). Product design and marketing and sales are managed in Europe whereas product manufacturing takes place in Asia. R&D takes place mainly in Japan, the US and Europe. Through patent cross-licensing however the research base becomes broader, including China, Taiwan and South Korea. Europe is suffering from fragmented funding. Asian countries have a high budget for R&D. LED commercialisation channels might face a reshuffle, in particular when the industry will be moving to lighting services. For LEDs to penetrate the market more, end-user information and training, as well as training for installers, would be necessary. LED is still a costly product, in particular in the general lighting segment where alternatives remain cheaper. The price needed for mass adoption has not yet been reached. It is estimated that a price of $8 would allow a 25% market share for LEDs. In Europe, a price of €10 would allow to reach, after some time, a 50% market share for LEDs versus 50% for CFLs in the residential sector. It is to be noted that the price for LED bulbs differs from one country to another, e.g. LED bulbs are cheaper in Japan than they are in the US or Europe. Despite the potential of SSL for energy efficiency and also better lighting, many obstacles to its development remain. Cost and consequently payback time are not yet in the advantage of LED-based general illumination, compared to conventional lighting technologies. Quality is an issue, particularly in the absence of standards, both for testing and for final products. Luminous efficacy and lifetime can still be improved. Last but not least, educational barriers remain, that could be overcome by training of all players in the market, from the designer to the user. As far as the environment is concerned, LEDs do not contain mercury. Life cycle analysis seems to be quite favourable for SSL but further research into environment and health benefits will be required to confirm this. Some of the obstacles to mass adoption in the general lighting segment will disappear as technology evolves to cheaper products with better light quality. But price and energy efficiency might not be the only selling elements for LEDs. Innovation might be an important asset when designing new lighting products. Further legislation and policy initiatives addressing SSL will need to be designed in such a way to reinforce Europe's strategic strengths in the lighting sector, as proposed in the Green paper on SSL of the European Commission.JRC.F.7-Renewable Energ

Load Modeling and Evaluation of LEDs for Hardware Test Bed Application

The lighting industry was revolutionized with the emergence of LED lighting. Over the last 15 years, LED lighting device sales and utilization have grown immensely. The growth and popularity of LEDs is due to improved operation of the device when compared to previous lighting technologies. Efficient performance of the device is critical due to the growth of global energy consumption. As nonrenewable generation fuel is finite, utilities have begun the transition to renewable energy generation. Generation and distribution systems become inherently complex to comprehend and maintain with incorporation of emerging supply and load technologies. With the unprecedented growth of LED bulbs, there are concerns regarding the impact of their integration on power systems. In determination of the effects, which LED bulb adoption posed within the power grid, investigation of this device as a grid-load was pursued. This thesis reviews existing studies pertaining to LEDs and power grid load modeling methodologies. Load modeling aids in establishing a balance between energy generation and consumption, comprehensively characterizing relationships between electrical generation, transmission, distribution, and loads. Due to the complexities of large networked systems, device load models are constructed and aggregated in emulation of the interactive relationships throughout the power grid. This thesis includes a study of preestablished LED bulb ZIP load models and formulation of a component-based load model for improved characterization of a conventional LED lighting device. Load modeling was conducted with reference to the UTK HTB, for future integration and improved grid emulation. Factors, such as shape, size, illumination, and the power rating of popular LED bulbs is examined. Through investigation of typical LED bulb topologies, a model is formulated, in representation of device behavior as a load. The established load model’s characteristics are tested with comparison to physical device operation in a laboratory environment. The LED bulb component-based model is simulated under dynamic conditions in portrayal of device behavior under fault scenarios. An interactive interface is formulated for simulation of load behavior throughout grid level events. Detailed analysis of data and methods of implementation is provided, in characterization of the LED bulb’s load profile

Characterizing Light Output Variations from Solid State Lighting Due to High Frequency Electromagnetic Interference

Consumer electronic devices employing active power electronic switching have been increasingly used in the last decade. With the rise in number of these devices, the emission of harmonic currents by these devices has changed both in magnitude and character. The effects of harmonic frequencies up to 2000 Hz on various electrical and electronic devices has been the subject of considerable scrutiny over the past decade. However, newer consumer devices employ switched mode power electronic circuits that switch in the multiple kilohertz range. The emission from these devices, along with power line communication, are sources of high frequency currents in the range of 2 to 150 kHz. As a result, there has been an appreciable rise in the amount of conducted emission in the frequency range 2 to 150 kHz. One of the important outcomes of rising emission in this frequency range is that there have been reported cases of interference with various consumer electronic devices. Among the devices in which interference has been reported are the new generation of solid state LED lamps which have become popular in the last 3-5 years. Considerable research has been done in the past about the effects of light flicker and the modulation of light output from incandescent lamps, on human beings. However, the utilization of power electronic converters changes this paradigm considerably. Unlike incandescent bulbs, where low frequency modulation of input voltage resulted in visible flicker, observations and reports have shown that LED lamps may be susceptible to flicker from frequencies above the 2 kHz mark. As a result, old methods of predicting flicker and studying it may no longer be applicable. This thesis attempts to shorten this gap in knowledge by exploring the topic of LED flicker due to high frequency distortion, and the factors that affect it. This was achieved by exposing LED lamps of various sizes and from various manufacturers, to realistic voltage distortion signals, recorded in the power system. Signals with high-frequency distortion superimposed on to the fundamental, were used. The test set-up used, allowed for the testing of light equipment with various types and levels of distortion at different points on wave. For the first time, experimental results showed that not only does high frequency voltage distortion cause changes in average value of light output and the modulation of light output, but that this change depends upon the point-on-wave at which the high frequency distortion appears. The mathematical tool of cross-correlation was proposed to quantify the effect of point-on-wave of high frequency distortion on light output. The utilization of this tool showed that LED lamps are susceptible to distortion appearing near the peak or near the zero crossing of the input voltage. In order to understand the dependence of LED flicker on the topology of the LED driver, five LED driver development boards available commercially were also subjected to the above mentioned high frequency voltage distortion. The results showed that light flicker from LED lamps is not necessarily a by-product of LED driver topology. The utilization of discontinuous conduction mode of operation and an isolation transformer in the LED driver is not sufficient to disconnect the LED load from input voltage variations. LED drivers of the same topology can behave completely different, likely due to the control methodology employed by each manufacturer. Finally, a simulation model of a popular LED driver solution: a flyback DC-DC converter with primary side regulation was developed to verify the experimental results and perform root cause analysis for the observed phenomena. Changes in control methodology and circuit design were suggested to overcome this flicker problem and evidence of the degradation of circuit components due to excess heat generated by high frequency distortion was shown

Potential of using photovoltaic systems to power underwater fishing lights in small-scale fishing vessel in Indonesia

The limited stock and uncertainty of fuel prices as a source of driving the main engine and generator on ships greatly affect the lives of fishermen in Indonesia. Even though there is a policy in the form of assistance from the government in the form of subsidies, fishermen still feel doubtful about being able to get such assistance. To overcome this and with the potential of solar energy in Indonesia, as well as a manifestation of appropriate technology and blue economy policies, a photovoltaic system is made that is combined with underwater lights as a fishing tool. Activities are carried out by measuring environmental conditions and the energy that comes out of the PV system and giving questionnaires to the fishermen. The results showed that the use of PV systems combined with underwater lights in fishing activities gave good results. The result of electrical energy that can be generated is 393.24 Wh/day and can meet the ship’s electricity needs for 4 days. This result is also supported by the Wilcoxon test results for technical, economic, environmental, health, and safety aspects with a significance value of 0.001 (p<0.05)

An automotive interior lighting application using white light-emitting diodes

Includes bibliographical references.In this thesis the commercially available white light-emitting diode (LED) with its inherent efficiency, longevity and mechanical strength, is used to show, that success in energy efficiency can be obtained. Two cases are used to illustrate the need for efficient demand-side technology: the electricity shortages of the Western Cape Province in South Africa and a white LED pilot project in Namulonge, Uganda

Revision of the EU Green Public Procurement Criteria for Street Lighting and Traffic Signals - Preliminary Report

Lighting is used on more than 1.6 million km of roads in EU28 countries, accounting for some 35 TWh of electricity consumption (1.3% of total electricity consumption) and costing public authorities almost €4000 million each year. A broad review of relevant technical, policy, academic and legislative literature has been conducted. This report examines the current market situation and the potential for reducing environmental impacts and electricity costs by assessing the recent developments in road lighting technology, particularly LEDs. Particularly important areas identified relate to energy efficiency, light pollution, product durability and, specifically for longer lasting and rapidly evolving new LED technologies, reparability and upgradeability. The information in this report shall serve as a basis for discussion with stakeholders about the further development and revision of EU GPP criteria for street lighting and traffic signals.JRC.B.5-Circular Economy and Industrial Leadershi

An automotive interior lighting application using white light-emitting diodes

Includes bibliographical references.In this thesis the commercially available white light-emitting diode (LED) with its inherent efficiency, longevity and mechanical strength, is used to show, that success in energy efficiency can be obtained. Two cases are used to illustrate the need for efficient demand-side technology: the electricity shortages of the Western Cape Province in South Africa and a white LED pilot project in Namulonge, Uganda