scholarly journals Electro-optical characteristics of an innovative LED luminaire with an LED matrix cooling system based on heat pipes

2020 ◽  
Vol 23 (04) ◽  
pp. 415-423
Author(s):  
D.V. Pekur ◽  
◽  
V.M. Sorokin ◽  
Yu.E. Nikolaenko ◽  
V.P. Kostylyov ◽  
...  
Keyword(s):  
Light Source ◽  
Cooling System ◽  
Renewable Energy Sources ◽  
Heat Pipes ◽  
Luminous Flux ◽  
Optical Characteristics ◽  
Led Light ◽  
Lighting Systems ◽  
Led Matrix ◽  
Led Luminaire

Widespread use of energy-saving LED lighting systems powered by renewable energy sources, solar energy in particular, will contribute to the improvement of global ecology. One of the structural elements of such lighting systems is LED luminaire. The authors of this article perform a first ever experimental study of electro-optical characteristics of the basic version of a compact high-power LED luminaire for indoor use. The particular feature of this lighting device is that its cooling system for the LED light source is based on heat pipes and concentric cooling rings. Such design allows ensuring the required cooling efficiency of the LED matrix. The revealed trends in optical and electrical parameters during temperature stabilization indicate that the proposed cooling system is highly efficient in maintaining normal thermal conditions of LED light sources with a power of up to 140.7 W and a luminous flux of up to 15083 lm. The results on determining spatial distribution of luminous flux of these luminaires indicate that they may be used for lighting large rooms with high ceilings. Scaling the basic modular design version of the cooling system allows increasing the power of the LED light source up to 600 W.

scholarly journals Experimental study of a compact cooling system with heat pipes for powerful LED matrices

2020 ◽  
pp. 35-41 ◽  
Author(s):  
D. V. Pekur ◽  
V. M. Sorokin ◽  
Yu. E. Nikolaenko
Keyword(s):  
Heat Exchanger ◽  
Light Source ◽  
Cooling System ◽  
Heat Pipes ◽  
Ambient Air ◽  
Working Fluid ◽  
Light Sources ◽  
Measured Temperature ◽  
Led Light ◽  
Led Matrix

LED light sources, and powerful multichip light sources in particular, are currently widely used for lighting household and industrial premises. With an increase in power, the amount of heat increases as well, which leads to an increase in the temperature of semiconductor crystals and, accordingly, to a decrease in the reliability of LEDs and a change in their photometric characteristics. Therefore, when developing the design of LED lighting devices, special attention is paid to thermal management. Since the early 2000s, heat pipes have been widely used to efficiently remove heat from powerful electronic components. They do not require power for moving the working fluid and are most suitable for use in LED luminaires. In this study, the authors carry out a computer simulation of a cooling system based on heat pipes, which is then used to design and test a powerful compact LED lamp with a thermal load of up to 100 W. Heat pipes with a length of 150 mm are used to remove heat from the LED light source to the heat exchanger rings located concentrically around it. The heat exchanger rings are cooled by natural convection of the ambient air. The results of computer modeling of the temperature field of the developed cooling system show that at a power of the LED light source of 140.7 W, the temperature of the LED matrix case is 60.5°C, and the experimentally measured temperature is 61.3°C. The experimentally determined thermal power of the LED matrix is 91.5 W. The p–n junction temperature is 79.6°C. The total thermal resistance of the cooling system is 0.453°C/W. The obtained results indicate the effectiveness of the developed design.

scholarly journals New LED lamp design with heat pipes

2019 ◽  
pp. 34-42 ◽  
Author(s):  
D. V. Pekur ◽  
Yu. E. Nikolaenko ◽  
V. M. Sorokin
Keyword(s):  
Heat Exchanger ◽  
Thermal Resistance ◽  
Light Source ◽  
Cooling System ◽  
Heat Pipes ◽  
Ambient Air ◽  
Light Sources ◽  
Heat Conducting ◽  
Led Light ◽  
Semiconductor Crystals

The problem of climate change poses a challenge for humanity: it is necessary to reduce harmful emissions into the atmosphere, caused mainly by the burning of coal in thermal power plants. Partially, this problem can be solved by the use of energy-saving devices and equipment, including the replacement of traditional light sources with more efficient LEDs. This, however, causes the problem of ensuring normal thermal modes of the LEDs, since the more powerfull the LED is, the more heat is released in their semiconductor crystals, which leads to an increase in the temperature of the crystals and a decrease in the reliability of the device. This problem becomes especially urgent when using powerful multi-chip LED light sources, the so-called SOB matrices, whose power even now exceeds 500 W. This article presents a new design of a powerful LED lamp for indoor illumination of rooms with low ceilings. The heat from the LED is transferred via heat pipes to the heat exchanger rings looped around the light source. The heat exchanger rings are cooled by the natural convection of the surrounding air (at an ambient air temperature of 20°C). Computer simulation allowed evaluating the ability of the proposed cooling system to provide a normal thermal mode of the LED light source. The results on the computer simulations of the temperature field of light source`s cooling system showed that when the LED power is 300 W, the temperature of the light source`s base at the point where it is connected to the light source does not exceed 67.6°C. When the contact zone is covered with a 0.1 mm layer of heat-conducting paste (Arctiс Silver 5 type) with a thermal conductivity coefficient of 8.7 W/(m•°C), the temperature of the LED case reaches 70°C. If the thermal resistance of the LED light source is 0.1°C/W, then the temperature of its semiconductor crystals will be 100°C, well below the allowable temperature value of 150°C. The total thermal resistance of the cooling system is 0.159°C/W.

Design of Solar-Powered LED Road Lighting System

2019 ◽  
pp. 75-85
Author(s):  
Canan Perdahci ◽  
Hamdi Ozkan
Keyword(s):  
High Pressure ◽  
Renewable Energy Sources ◽  
Junction Temperature ◽  
Mercury Vapour ◽  
Light Sources ◽  
Street Lighting ◽  
Led Light ◽  
Road Lighting ◽  
Lighting Systems ◽  
High Pressure Sodium Lamp

Turkey is rich in terms of renewable energy sources and, therefore, is now encouraging the use of sustainable clean lighting systems in road applications. High pressure sodium lamp is the most widely used type in main roads, but other types of lamps such as mercury vapour lamps or metal halide lamps can be utilized for street lighting. Since it enables energy and money saving, LED light technology has replaced high pressure sodium lamps nowadays. Once solar power system (PV) is integrated with LED lamp for street lighting, the amount of saving and local impact might be enriched. LEDs used as light sources in road lighting luminaires with rising lumen values, decreasing junction temperature, higher colour rendering efficiency, longer lifetime have become more efficient than many light sources with the latest developments. Since the structure of the luminaires in which the LED light sources are used differs from that of the conventional light sources, the optical, thermal and electrical design of the LED luminaires must be considered differently. Thus, this study concentrates upon design considerations and the operating principle of solarpowered LED road lighting luminaire in details. Also, a simple solar panel system was designed and the economical values obtained at the end of 20 years were compared when using the ongrid system and the off-grid system.

scholarly journals Optimization of LED Lighting for Clinical Settings

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Snjezana Soltic ◽  
Andrew Chalmers
Keyword(s):  
Light Source ◽  
Performance Criteria ◽  
Source Spectrum ◽  
Clinical Settings ◽  
Colour Properties ◽  
Led Lighting ◽  
Led Light ◽  
De Algorithm ◽  
Lighting Systems ◽  
Spectral Design

The advent of the LED light source has promoted the concept of human-centric lighting (HCL). The LED has also been responsible for increases in the electrical efficiency of lighting systems, coupled with recent improvements in their colour properties. We have found that it is also possible to create a lit environment with enhanced clinical attributes by providing a source spectrum that meets the requirements of the Cyanosis Observation Index (COI). This paper describes the use of a differential evolution (DE) algorithm for the spectral design of a mixed LED light source capable of meeting COI recommendations as well as HCL performance criteria.

scholarly journals Research on adjustable correlated color temperature COB-LED light source based on flip chips and screen printing technology

2021 ◽  
Author(s):  
Rongrong Zhang ◽  
Zuojie Wen ◽  
Bingqian Li ◽  
Shenghua Liang ◽  
Mingde Yang ◽  
...  
Keyword(s):  
Light Source ◽  
White Light ◽  
Screen Printing ◽  
Light Emitting Diode ◽  
Luminous Flux ◽  
Color Temperature ◽  
Current Ratio ◽  
Led Light ◽  
Driving Current ◽  
Screen Printing Technology

Abstract Using the characteristic of flip light emitting diode (LED) chips without front-side welding wires, before applying fluorescent glue throughout the luminous surface, a part of the chips are directionally and quantitatively coated fluorescent glue by screen printing process, a chip on board (COB) white LED light source is developed with adjustable correlated color temperature (CCT). A part of the blue LED chips in the light source excites the fluorescent glue to produce a warm white light (CCT = 2631K), and the other part produces cool white light (CCT = 6181K). When changing the driving current ratio of the two parts of the chips, the CCT of COB LED light source can be continuously adjusted between warm and cool white light. According to the measured data, the relationship between the CCT and the driving current ratio of the two parts is obtained by fitting. Within the adjustable range of the CCT (2631 K to 6181 K), the color rendering index (CRI) is about 90. The minimum is 89.3 and the maximum is 93.1. While achieving adjustable CCT and high CRI, the LED light source has a luminous flux of 1938.76 lm on a circular surface with a diameter of 11 mm. The overall luminous efficiency is close to 100 lm/W.

Influence of Encapsulated Silica Gel on Output Luminous Flux of Deep Sea LED Light Source

2020 ◽  
Vol 41 (10) ◽  
pp. 1302-1308
Author(s):  
Tong CHEN ◽  
◽  
Fei WANG ◽  
Lu-qiao YIN ◽  
Jian-hua ZHANG
Keyword(s):  
Light Source ◽  
Silica Gel ◽  
Deep Sea ◽  
Luminous Flux ◽  
Led Light
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