Journal articles: 'LED heat management'

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Ekpu, Mathias, Eugene A. Ogbodo, Felix Ngobigha, and Jude E. Njoku. "Thermal Effect of Cylindrical Heat Sink on Heat Management in LED Applications." Energies 15, no. 20 (October 14, 2022): 7583. http://dx.doi.org/10.3390/en15207583.

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Light Emitting Diode (LED) applications are increasingly used in various microelectronic devices due to their efficient light generation. The miniaturisation of the LED and its integration into compact devices within the weight limit have resulted in excessive heat generation, and inefficient management of this heat could lead to the failure of the entire system. Passive and/or active heat sinks are used for dissipating heat from the system to the environment to improve performance. An ANSYS design modeller and transient thermal conditions were utilised in this study to design and simulate the LED system. The modeller performs its function by utilising the Finite Element Method (FEM) technique. The LED system considered in this work consists of a chip, thermal interface material, and a cylindrical heat sink. The thickness of the Cylindrical Heat Sink (CHS) fins used in the investigation is between 2 mm and 6 mm, whilst ensuring the mass of heat sinks is not more than 100 g. The input power of the LED chip is between 4.55 W and 25.75 W, as required by some original equipment manufacturers (OEMs). A mesh dependency study was carried out to ensure the results were synonymous with what can be obtained practically. The simulation results suggest that the power ratings did not affect the thermal resistance of the CHS. In addition, the thermal resistance increased with the increased thickness of the CHS fin. The efficiencies of the heat sink were found to increase with an increased thickness of the cylindrical fin and the accuracy between the calculated and simulated thermal efficiency ranges from 84.33% to 98.80%. Evidently, the CHS fin of 6 mm thickness is more efficient than the other CHS fins, as depicted in this study.

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Buergel, Erich. "LED Design – A Heat Management Challenge for Automobiles." ATZelektronik worldwide 7, no. 2 (April 2012): 20–23. http://dx.doi.org/10.1365/s38314-012-0081-6.

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Kintz, K. Andrew, Sara N. Paisner, and M. Shane Thompson. "THERMAL MANAGEMENT SOLUTIONS FOR THE LED MARKET." International Symposium on Microelectronics 2010, no. 1 (January 1, 2010): 000151–55. http://dx.doi.org/10.4071/isom-2010-ta5-paper3.

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High-brightness light emitting diodes (LEDs) are challenged with thermal management issues due to increased power and reduced surface area. This has led to the need for new materials with higher thermal conductivity that can quickly remove the heat from the active layer. LORD Corporation has developed two new thermal management materials, a “no pump-out” thermal grease and a low modulus die attach adhesive, as solutions to the heat dissipation problems facing LED manufacturers. These innovative technologies will help engineers solve complex fundamental thermal management problems. A new 4 W/mK silicone thermal grease has been developed with significant resistance to in-package bleed-out or pump-out eliminating the reliability problem most commonly encountered with traditional thermal greases. A new 10–20 W/mK thermal epoxy adhesive has also been developed creating a new class of flexible adhesives with high adhesion. This combination allows the new LORD die attach adhesive to not only effectively transfer heat out of the package, but also to dissipate the stress caused by thermal expansion and contraction during thermal cycling thereby affording improved package reliability.

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Maaspuro, Mika. "Novel Ideas for Thermal Management of Filament LED Light Bulbs." International Journal of Online and Biomedical Engineering (iJOE) 17, no. 08 (August 16, 2021): 60. http://dx.doi.org/10.3991/ijoe.v17i08.23695.

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The thermal conditions of a filament LED retro light bulb has been investigated. In such light bulbs, LEDs are mounted on filaments which have glass or sapphire substrate and are surrounded by yttrium-aluminium-garnet (YAG). Heat management is challenging as a heatsink cannot normally be used. Instead, heat removal is enabled by using helium as the filling gas. As this provides less efficient heat removal than using a heatsink attached directly to an LED module, LEDs operate in filament LED bulbs typically at rather high temperatures. In this paper thermal performance of a typical filament LED bulb has been studied. LED temperatures and gas flows inside the bulb has been resolved for cases of different orientations of the bulb. Thermal conditions for different filling gases have been resolved. All this has been done using finite element method (FEM) simulations. The main target of this study has been to find out novel solutions for thermal management of filament LED bulbs. Two heat removal solutions have been studied, namely the use of an internal heatsink and an internal piezoelectric oscillating cantilever fan. The results show that solutions can indeed reduce temperature of LED chips and increase the lifespan of the LED bulb.

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Petroski, James. "Advanced Passive Thermal Management for LED Bulb Systems." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2013, DPC (January 1, 2013): 001277–93. http://dx.doi.org/10.4071/2013dpc-wa34.

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The movement to LED lighting systems worldwide is accelerating quickly as energy savings and reduction of hazardous substances (RoHS) increase in importance. Furthering this trend are government regulations, rebate programs and declining prices. The market drive today is to replace light bulbs of common outputs (60W, 75W and 100W) without resorting to Compact Fluorescent (CFL) bulbs containing mercury while maintaining the standard industry bulb size and shape referred to as A19 for fixture retrofitting. This A19 size and shape restriction causes a small heat sink which is only capable of dissipating heat for 60W equivalent LED bulbs with natural convection. 75W and 100W equivalent bulbs require larger sizes, some method of forced cooling, or some unusual liquid cooling system; generally none of these approaches are desirable for light bulbs from a consumer point of view. Thus, there is interest in developing natural convection cooled A19 light bulb designs for LEDs that cool far more effectively than today's current designs. Current A19 size heat sink designs typically have thermal resistances of 5–7 °C/W. A more efficient method of cooling can be created using a chimney-based design to lower system thermal resistances below 4 °C/W while meeting all other requirements for bulb system design. Numerical studies and test data are in good agreement for various orientations including methods for keeping the chimney partially active in horizontal orientations. Such chimney-based designs are capable of cooling 75W and 100W equivalent LED light bulbs in the limited volume constraints of A19-size devices.

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Ramesh, Thangamani, Ayyappan Susila Praveen, Praveen Bhaskaran Pillai, and Sachin Salunkhe. "Numerical simulation of heat sinks with different configurations for high power LED thermal management." International Journal for Simulation and Multidisciplinary Design Optimization 13 (2022): 18. http://dx.doi.org/10.1051/smdo/2022009.

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This study performed a steady-state numerical analysis to understand the temperature in different heat sink configurations for LED applications. Seven heat sink configurations named R, H-6, H-8, H-10, C, C3, and C3E3 were considered. Parameters like input power, number of fins, heat sink configuration were varied, and their influence on LED temperature distribution, heat sink thermal resistance and thermal interface material temperature were studied. The results showed that the temperature distribution of the H-6 heat sink decreased by 46.30% compared with the Cheat sink for an input power of 16 W. The result of the H-6 heat sink shows that the heat sink thermal resistance was decreased by 73.91% compared with the Cheat sink at 16 W. The lowest interface material temperature of 54.11 °C was achieved by the H-6 heat sink when the input power was used 16 W. The H-6 heat sink exhibited better performance due to more surface area with several fins than other heat sinks.

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Ding, Xin Rui, Yu Ji Li, Zong Tao Li, Yong Tang, Bin Hai Yu, and Dong Yuan. "The Application of Heat Pipe Heat Sink for High Power LED Lamps." Applied Mechanics and Materials 602-605 (August 2014): 2713–16. http://dx.doi.org/10.4028/www.scientific.net/amm.602-605.2713.

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LED has been regarded as the next generation lighting source. As for high power LED lamps, heat accumulation will cause a series of problems. Therefore, thermal management is very important for designing a high power LED lamp. Three types of heat sinks are designed by using the finite element analysis (FEA) method for an 180W high power LED lamp. Then the optimized heat sinks are developed and experiments are performed to demonstrate the simulated results. At the same time, the thermal performances with different working angles are investigated experimentally. The heat sink with heat pipe has a better heat dissipation performance than the conventional heat sink under the same input power. The working angles of the lamps greatly influence the thermal performance of each heat sink. For the same heat sink, the temperature varies with different install directions and working angles. Finally, the heat sink with the best thermal performance is recommended. The results have practical significance in designing high power LED lamps.

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Zhang, Jian Xin, Ping Juan Niu, Da Yong Gao, and Lian Gen Sun. "Research Progress on Packaging Thermal Management Techniques of High Power LED." Advanced Materials Research 347-353 (October 2011): 3989–94. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.3989.

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In order to dominate the lighting market, LED needs more electrical power to be driven for higher brightness, thereby increasing thermal power dissipation, which contributes to a high heat flux of 85W/cm2 within a recent typical high power LED chip. And the junction temperature has direct influence upon the light output efficiency, device life time, emitting wavelength and reliability of LED. Therefore, effective removal of heat to maintain a safe junction temperature is the key to meet the future flux per LED requirements. Compared with other individual thermal resistances along the thermal path, thermal design for much lower packaging thermal resistance is more critical to improve the performances of LED. In this paper, major present technical researches on packaging thermal management were analyzed for high power LED, and the advantages and shortcomings of these techniques were respectively summarized. Besides, some suggestions were provided for further research in this area.

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Sauli, Zaliman, Rajendaran Vairavan, and Vithyacharan Retnasamy. "Heat Sink Fin Number Variation Analysis on Single Chip High Power LED." Applied Mechanics and Materials 487 (January 2014): 149–52. http://dx.doi.org/10.4028/www.scientific.net/amm.487.149.

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Thermal management of high power LED is crucial the reliability and performance of the LED affected by the heat produced during photon emission. Heat sinks are utilized to dissipate the heat and to lower the operating junction temperature of LED. This paper demonstrates a simulation work done to evaluate the influence heat sink fin number on the junction temperature and stress of single chip LED package using Ansys version 11. The heat sink with fin number of 4 fins, 6 fins and 8 fins were used and compared. Results showed that increase in heat sink fin number significantly reduces the junction temperature of the LED package.

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Zhao, Xinjie, Yixi Cai, Jing Wang, and Xiao-Hua Li. "EXPERIMENTAL STUDY OF THERMAL MANAGEMENT OF LED AUTOMOTIVE HEADLAMPS USING HEAT PIPES." Heat Transfer Research 47, no. 10 (2016): 975–87. http://dx.doi.org/10.1615/heattransres.2016010569.

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11

Lu, Libin, Zhen Zhang, Yingchun Guan, and Hongyu Zheng. "Enhancement of Heat Dissipation by Laser Micro Structuring for LED Module." Polymers 10, no. 8 (August 8, 2018): 886. http://dx.doi.org/10.3390/polym10080886.

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Optimization for heat dissipation plays a significant role in energy saving and high-efficiency utilizing of integrated electronics. In this paper, we present a study of micro structuring on polymer-based flexible substrate coupled with aluminum-alloy heat sink. The heat dissipation performance was investigated by temperature evolution of a heat sink under natural convection by infrared (IR) camera, and results showed that the heat dissipation enhancement could be up to 25%. Moreover, the heat dissipation performance of a typical heat sink in terms of light-emitting diode (LED) hip was investigated via both thermal transient measurement and the finite element analysis (FEA). The maximum LED chip temperature of the laser-textured heat sink was approximately 22.4% lower than that of the as-received heat sink. We propose that these properties accompanied with the simplicity of fabrication make laser surface texturing a promising candidate for on-chip thermal management applications in electronics.

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Ben Salah, Sana, and Mohamed Bechir Ben Hamida. "Alternate PCM with air cavities in LED heat sink for transient thermal management." International Journal of Numerical Methods for Heat & Fluid Flow 29, no. 11 (November 4, 2019): 4377–93. http://dx.doi.org/10.1108/hff-02-2019-0099.

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Purpose The purpose of this paper is to optimize the configuration of a heat sink with phase change material for improving the cooling performance of light emitting diodes (LED). Design/methodology/approach A numerical three-dimensional time-dependent model is developed with COMSOL Multiphysics to simulate the phase change material melting process during both the charging and discharging period. Findings The model is validated with previously published works. It found a good agreement. The difference between filled cavities with phase change materials (PCM) and alternate cavities air-PCM is discussed. The last-mentioned showed a good ability for reducing the junction temperature during the melting time. Three cases of this configuration having the same total volume of PCM but a different number of cavities are compared. The case of ten fins with five PCM cavities is preferred because it permit a reduction of 21 per cent of the junction temperature with an enhancement ratio of 2:4. The performance of this case under different power input is verified. Originality/value The use of alternate air-PCM cavities of the heat sink. The use of PCM in LED to delay the peak temperature in the case of thermal shock (for example, damage of fan) An amount of energy is stored in the LED and it is evacuated to the ambient of the accommodation by the cycle of charging and discharging established (1,765 Joule stored and released each 13 min with 1 LED chip of 5 W).

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13

WAN, Zhongmin. "Research on Porous Micro Heat Sink for Thermal Management of High Power LED." Journal of Mechanical Engineering 46, no. 08 (2010): 109. http://dx.doi.org/10.3901/jme.2010.08.109.

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Jeng, Tzer Ming, Sheng Chung Tzeng, Po Tsun Chen, and Wei Kai Huang. "Heat Transfer Analysis for Line-Finned Heat Sink with Vertical Passages." Applied Mechanics and Materials 764-765 (May 2015): 300–304. http://dx.doi.org/10.4028/www.scientific.net/amm.764-765.300.

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Using heat sink to increase the cooling area is the most familiar and fundamental method in LED heat management technology. We develop a new configuration of finned heat sink for LED lamp. It is a circular cylinder with many plate fins radially arranged on the external surface. There are many straight ducts inside the peripheral wall of the cylinder. These ducts form the chimney effect to enhance the heat transfer. This work experimentally investigated the chimney effect on the heat transfer characteristics of the finned heat sink under the free convection state. The aluminum-alloy plate spreader with two vertical plate fins was selected as the control group. The experimental group was the heat sink having the same configuration of the control group but had a vertical passage within the spreader. The results show that the vertical passage did strengthen 8.3~12.1% free convection performance for the present test heat sink.

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Sheen, Maw Tyan, Ming Der Jean, and Yu Tsun Lai. "Application of Micro-Tube Water-Cooling Device for the Improvement of Heat Management in Mixed White Light Emitting Diode Modules." Advanced Materials Research 308-310 (August 2011): 2422–27. http://dx.doi.org/10.4028/www.scientific.net/amr.308-310.2422.

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This paper introduces a module using the RGB-based LED design to improve the thermal management of a mixied white light LED and describes a system for heat dissipation in illuminated, high-power LED arrays. Mixed light LEDs can be produced by combining appropriate amounts of light from the red, green and blue LEDs in an array. A LED cooling system, using a micro- tube water-cooling device, was fabricated. Recycling water in the system, gave more efficient convection and the heat created by the LEDs was easily removed, in the experiments. It was shown that micro-tube water-cooling systems rendered an improvement in thermal management that effectively decreases the thermal resistance and provides very good thermal dissipation. Furthermore, the results of experiment and simulation demonstrated that a micro-tube water-cooling system is very effective in heat dissipation in LEDs and the fabrication of practical micro-water tube cooling devices for mixing light LEDs was feasible and useful

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Ali, Zulfiqar, Yuan Gao, Bo Tang, Xinfeng Wu, Ying Wang, Maohua Li, Xiao Hou, Linhong Li, Nan Jiang, and Jinhong Yu. "Preparation, Properties and Mechanisms of Carbon Fiber/Polymer Composites for Thermal Management Applications." Polymers 13, no. 1 (January 5, 2021): 169. http://dx.doi.org/10.3390/polym13010169.

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With the increasing integration and miniaturization of electronic devices, heat dissipation has become a major challenge. The traditional printed polymer circuit board can no longer meet the heat dissipation demands of microelectronic equipment. If the heat cannot be removed quickly and effectively, the efficiency of the devices will be decreased and their lifetime will be shortened. In addition, the development of the aerospace, automobiles, light emitting diode (LED{ TA \1 “LED; lightemitting diode” \s “LED” \c 1 }) and energy harvesting and conversion has gradually increased the demand for low-density and high thermal conductive materials. In recent years, carbon fiber (CF{ TA \1 “CF; carbon fiber” \c 1 }) has been widely used for the preparation of polymer composites due to its good mechanical property and ultra-high thermal conductivity. CF materials easily form thermal conduction paths through polymer composites to improve the thermal conductivity. This paper describes the research progress, thermal conductivity mechanisms, preparation methods, factors influencing thermal conductivity and provides relevant suggestions for the development of CF composites for thermal management.

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Zhao, Xin Jie, Yi Xi Cai, Jing Wang, Xiao Hua Li, and Chun Zhang. "Thermal Analysis and Optimization of High Power LED Automotive Headlamp Cooling Device." Applied Mechanics and Materials 457-458 (October 2013): 399–404. http://dx.doi.org/10.4028/www.scientific.net/amm.457-458.399.

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High power LED headlamp cannot operate normally and efficiently in case the maximum junction temperature exceeds 120°C. Therefore, it is essential to install external cooling device with excellent thermal management. A model based on plate-fin heat sink is presented, the heat transfer plates (HTPS) are added to bridge aluminum substrate and heat sink. And its thermal performance is evaluated compared with the one only installing heat sink. Results reveal the HTPS coupled with heat sink has a good cooling performance. In addition, the correlation between the junction temperature and the HTPS length is investigated. The optimum length is 47 mm. Furthermore, considerable simulation and experiment are conducted on the junction temperature variation subject to input power, ambient temperature, as well as the installation angle respectively. Finally, a fan is added based on the original device to enhance cooling. It indicates that the junction temperature decreases gradually with the presence of velocity air flow.

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Gil, Paweł, Joanna Wilk, Slawomir Smolen, Rafał Gałek, Marek Markowicz, and Piotr Kucharski. "Experimental Investigations of the LED Lamp with Heat Sink Inside the Synthetic Jet Actuator." Energies 15, no. 24 (December 12, 2022): 9402. http://dx.doi.org/10.3390/en15249402.

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The paper presents the experimental research on the thermal management of a 150 W LED lamp with heat sink inside a synthetic jet actuator. The luminous flux was generated by 320 SMD LEDs with a nominal luminous efficacy equal to 200 lm/W mounted on a single PCB. Characteristic temperatures were measured with three different measurement techniques: thermocouples, infrared camera, and an estimation of the junction temperature from its calibrated dependence on the LED forward voltage. The temperature budget between the LED junction and ambient as well as the thermal resistance network was determined and analyzed. The energy balance of the LED lamp is presented along with the values of the heat flow rate and heat transfer coefficient in different regions of the LED lamp surface. For an input power supplied to the SJA equal to 4.50 W, the synthetic jet dissipated approximately 89% of the total heat generated by the LED lamp. The heat from the PCB was transferred through the front and rear surfaces of the board. For the input power of 4.50 W, approximately 91% of the heat generated by LEDs was conducted by the PCB substrate to the heat spreading plate, while the remaining 9% was dissipated by the front surface of the PCB, mostly by radiation. The thermal balance revealed that for the luminous efficacy of the investigated LEDs, approximately 60% of the electrical energy supplied to the LED lamp was converted into heat, while the rest was converted into light.

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Acar Vural, Revna, İbrahim Demirel, and Burcu Erkmen. "Design and optimization of a power supply unit for low profile LCD/LED TVs." An International Journal of Optimization and Control: Theories & Applications (IJOCTA) 7, no. 2 (July 5, 2017): 158–66. http://dx.doi.org/10.11121/ijocta.01.2017.00440.

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The ongoing demand for smaller and lighter power supplies is driving the motivation to increase power density while maintaining a robust design compatible with international harmonic standards. Transformer design is a major challenge for low profile and high power density TV power cards. In addition to these, for electromagnetic interference standard and for providing efficient thermal management for heat emission, it is required to minimize EMI noise. In this study, by taking these stated criteria into consideration, a TV power card has been designed, which has 220W output power and can be used in low profile televisions. Proposed power card will meet desired critical parameters such as surface area and output power of the referenced card which has 13.5mm height, the heat, and power consumption at standby mode. Moreover, it is designed with 10mm height limit without any engraving on PCB in a way that it will meet International Electrotechnical Commission (IEC) current harmonic standard to which TVs are subjected. Experimental results demonstrate that the proposed power supply with 10mm height has 34% higher power density with respect to its counterpart having 13.5 mm height.

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Jou, Rong Yuan. "Heat Transfer Enhancement of the Liquid-Cooled LED Illumination Module." Applied Mechanics and Materials 284-287 (January 2013): 768–72. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.768.

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High-power light emitting diode (LED) modules offer several advantages over conventional light sources, but require effective thermal management for optimal performance, such as liquid cooling or thermoelectric cooling (TEC). This study compared the thermal performance of high-power LEDs with liquid cooling and TEC using both the finite element method and experiments. We considered a mutichip module in which the LEDs are immersed in one of three different cooling fluids in a metal enclosure with passive cooling or a TEC module. In the experiments, temperatures were measured by thermocouples. The temperature and flow fields of the liquid-cooled package inside the enclosure were analyzed in detail using a numerical model, and the results were validated against the experimental measurements. In this paper, we discuss the major design considerations when using liquid cooling and TEC. Our results show that for the illumination module considered in this study, appropriate heat sink design is crucial to optimizing performance with TEC, which can enhance the heat dissipation for small and compact LED modules.

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Kim, Hyo Tae, Jihoon Kim, Young Joon Yoon, Chang Yeoul Kim, Jong-hee Kim, Heung-soon Kim, and Gi-seok Song. "Thick Film Approaches in High Power LED Array Module." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2011, CICMT (September 1, 2011): 000130–33. http://dx.doi.org/10.4071/cicmt-2011-tp33.

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Light emitting diode, LED, has become a popular device for display and lighting applications. Among them, high power LED array modules are especially interested in the field of street light system, recently. High power LED array module is generally consisted of several pieces of LEDs which are mounted on the PCB with the combination of series and parallel circuits according to the designed operating voltage and power consumption, i.e. total wattages. Since the life time expectancy and brightness of LED are greatly influenced by the operation temperature of LED, thermal management technology of LED module including system design, heat transfer and dissipation become a hot issue in these days. In this work, we would like to present several thick film approaches to fabricate thermally efficient high power, i.e. LED array modules with over 50 watts by using different array package design, materials selection and film forming techniques. Here, we will demonstrate 50 watts LED array modules directly coupled with aluminum, copper or silicon heat sinks which operates at 12volts using 4 × 9, 4 pieces of LED in series multiplied by 9 arrays in parallel, LED array circuit. The microstructure of metal-ceramic multilayers and interfaces, and the heat transfer performance of the LED array modules will be presented.

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Pekur, D. V., V. M. Sorokin, and Yu E. Nikolaenko. "Experimental study of a compact cooling system with heat pipes for powerful LED matrices." Технология и конструирование в электронной аппаратуре, no. 3-4 (2020): 35–41. http://dx.doi.org/10.15222/tkea2020.3-4.35.

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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.

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Kosoy, Boris. "Micro channels in macro thermal management solutions." Thermal Science 10, no. 1 (2006): 81–98. http://dx.doi.org/10.2298/tsci0601081k.

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Modern progress in electronics is associated with increase in computing ability and processing speed, as well as decrease in size. Future applications of electronic devices in aviation, aero space and high performance consumer products? industry demand on very stringent specifications concerning miniaturization, component density, power density and reliability. Excess heat produces stresses on internal components inside the electronic device, thus creating reliability problems. Thus, a problem of heat generation and its efficient removal arises and it has led to the development of advanced thermal control systems. Present research analyses a thermodynamic feasibility of micro capillary heat pumped net works in thermal management of electronic systems, considers basic technological constrains and de sign availability, and identifies perspective directions for the further studies. Computer Fluid Dynamics studies have been per formed on the laminar convective heat transfer and pressure drop of working fluid in silicon micro channels. Surface roughness is simulated via regular constructal, and stochastic models. Three-dimensional numerical solution shows significant effects of surface roughness in terms of the rough element geometry such as height, size, spacing and the channel height on the velocity and pressure fields.

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Ben Hamida, Mohamed Bechir, Mohammed A. Almeshaal, and Khalil Hajlaoui. "A three-dimensional thermal analysis for cooling a square Light Emitting Diode by Multiwalled Carbon Nanotube-nanofluid-filled in a rectangular microchannel." Advances in Mechanical Engineering 13, no. 11 (November 2021): 168781402110599. http://dx.doi.org/10.1177/16878140211059946.

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The aim of this paper is to ensure proper thermal management in order to remove and dissipate the heat produced by a square Light Emitting Diode (LED), as well as to ensure stable and safe operation by reducing the junction temperature. For this, we developed a three-dimensional code, time-dependent that solves the systems of equations for the mass, momentum, and energy using Comsol Multiphysics. After validation of this numerical 3D code, the thermal performance of a LED cooling system with three nanofluids such as MWCNT-Water, MWCNT-Ethylene Glycol, and MWCNT-Engine oil is studied numerically into account of aggregation effect. Several parameters such as: the power of the LED lamp, the inlet temperature and velocity of nanofluid, the length of the heat sink, and the length of the microchannel have been varied in order to find an optimal condition allowing a good heat dissipation from the LED chip to the heat sink. It was concluded that the use of MWCNT-Water in the microchannel is the best nanofluid that can cool the heat sink. In addition, the increase of velocity inlet of the coolant in the microchannel, the length of the heat sink, and the microchannel length while the decrease of the inlet temperature of nanofluid in the microchannel are an important factors allowing the decrease of the junction temperature of the square LED lamp.

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Kim, Kyoung Joon. "Numerically-Investigated Thermal Performances of Hybrid Fin Heat Sinks for Lightweight Thermal Management of LED Modules Under Natural Convection." Journal of the Korean Society of Marine Engineering 39, no. 6 (July 31, 2015): 586–91. http://dx.doi.org/10.5916/jkosme.2015.39.6.586.

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Jean, Ming-Der, Cheng-Wu Liu, Tzu-Hsuan Chien, and Peng-Da Lei. "EXPERIMENTAL AND ANALYTICAL INVESTIGATION OF THERMAL MANAGEMENT OF LED ASSEMBLIES USING MICRO-HEAT COOLING DEVICES." Heat Transfer Research 50, no. 13 (2019): 1265–83. http://dx.doi.org/10.1615/heattransres.2018026420.

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Kim, Jong-Soo, and Eun-Pil Kim. "Analysis of the thermal management of a high power LED package with a heat pipe." Journal of the Korean Society of Marine Engineering 40, no. 2 (February 29, 2016): 96–101. http://dx.doi.org/10.5916/jkosme.2016.40.2.96.

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Kumar, Prem, Gopinath Sahu, Debartha Chatterjee, and Sameer Khandekar. "Copper wick based loop heat pipe for thermal management of a high-power LED module." Applied Thermal Engineering 211 (July 2022): 118459. http://dx.doi.org/10.1016/j.applthermaleng.2022.118459.

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Habib, Numan, Muftooh ur Rehman Siddiqi, and Muhammad Tahir. "Thermal analysis of proposed heat sink design under natural convection for the thermal management of electronics." Thermal Science 26, no. 2 Part B (2022): 1487–501. http://dx.doi.org/10.2298/tsci210402307h.

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The rapid development in the field of electronics has led to high power densities and miniaturization of electronic packages. Because of the compact size of electronic devices, the rate of heat dissipation has increased drastically. Due to this reason, the air-cooling system with a conventional heat sink is insufficient to remove large quantity of heat. A novel macro-channel ?L-shaped heat sink? is pro-posed and analyzed to overcome this problem. The thermal resistance and fluid-flow behavior under natural convection, of the novel and conventional air-cooled heat sink designs, are analyzed. Governing equations are discretized and solved across the computational domain of the heat sink, with 3-D conjugate heat transfer model. Numerical results are validated through experimentation. The effect of parameters i.e., fin height, number of fins and heat sink size, on the thermal resistance and fluid-flow are reported. Examination of these parameters provide a better physical understanding from energy conservation and management view point. Substantial increase in the thermal performance is noted for the novel ?L-shaped heat sink? compared to the conventional design.

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Stack, J. G., and M. S. Acarlar. "Heat Transfer and Thermal Stress Analysis of an Optoelectronic Package." Journal of Electronic Packaging 113, no. 3 (September 1, 1991): 258–62. http://dx.doi.org/10.1115/1.2905404.

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The reliability and life of an Optical Data Link transmitter are inversely related to the temperature of the LED. It is therefore critical to have efficient packaging from the point of view of thermal management. For the ODL® 200H devices, it is also necessary to ensure that all package seals remain hermetic throughout the stringent military temperature range requirements of −65 to +150°C. For these devices, finite element analysis was used to study both the thermal paths due to LED power dissipation and the thermally induced stresses in the hermetic joints due to ambient temperature changes

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Lin, Sheam-Chyun, Yu-Cheng Chen, Yu-Chun Wu, and Hung-Cheng Yen. "CHIMNEY-ENHANCED DESIGN APPLIED ON THE THERMAL MANAGEMENT OF LED VEHICLE HEADLAMP." Transactions of the Canadian Society for Mechanical Engineering 40, no. 4 (November 2016): 521–32. http://dx.doi.org/10.1139/tcsme-2016-0040.

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LED vehicle headlamp consists of several high-power LEDs and thermal module inside an enclosed space, and locates near the high-temperature engine compartment. Certainly, these factors results in a challenging task on the thermal management of headlamp. Obviously, the temperature stratification inside this bounded region is an unfavorable phenomenon for the natural-convection thermal module. This study utilizes the chimney effect to achieve a more uniform temperature distribution and thus enhance the heat-dissipation ability. Firstly, an enclosed space is selected for executing the parametric study on the chimney geometry. Several effective alternatives are obtained and verified via both numerical and experimental means on the chimney design. Also, a significant 4.6°C reduction on LED junction temperature is attained on the best chimney-enhanced module. Then, these guidelines are applied to a commercial LED headlamp. Consequently, a range of 3.8 ~ 4.6°C decrease on LEDs is found for this innovative chimney thermal module.

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Guero Mohamed, Moumouni, and Prodjinonto Vincent. "THERMAL ENHANCEMENTS OF A LED BASED AUTOMOTIVE HEADLAMP." International Journal of Advanced Research 10, no. 08 (August 31, 2022): 661–74. http://dx.doi.org/10.21474/ijar01/15219.

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Light Emitting Diode (LED) is a new kind of light source that is quickly being used into automotive lighting systems. In recent years, there have been increased expectations placed on vehicle headlamps, including that they not only be fully functional, affordable, and long-lasting, but also stylish, energy-efficient, and environmentally friendly. Since LED light sources are long-lasting, highly efficient, and energy-efficient, small in size, etc., they are frequently utilized in headlamps, turn signals, brake lights, position lights, etc. and will soon dominate the automotive light source industry. Although it has a greater energy conversion efficiency, the thermal management of LED headlamps is still a problem. In this research, the response surface method is used to optimize the heatsink designs for LED automotive headlamp module. The finite element (FE) approach and numerical simulation are used to model the test samples temperature distribution. Then, in order to maximize the heatsink potential for thermal dissipation, we tested different types of material, and used the response surface method. The LED headlamp hot spots decrease by 2 to 8 degrees when the heat sinks thickness, fin spacing, and height are optimized and decrease by 7.64 degrees when the heat sink and PCB substrate are made of 6063 aluminum alloy and AlN, respectively.

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Sim, Joshua Dao Wei, and Jason Kai Wei Lee. "A History of Heat Health Management Policies in the Singapore Military." Healthcare 11, no. 2 (January 10, 2023): 211. http://dx.doi.org/10.3390/healthcare11020211.

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Our paper, which is the first historical study about heat injuries in Singapore, seeks to situate the Singapore Armed Forces’ (SAF) history of heat stress management policies within the national context. Firstly, we observe that since the late 1970s, a research-driven approach has been adopted by the SAF’s military medical leaders to formulate a range of policies to address the Forces’ high incidence of heat injuries. This has resulted in the introduction of SAF-wide training measures, and the assembling of local scientific research expertise, which has led to a sharp reduction in heat injury incidence from the 1980s to 2000s. Through this, the SAF sought to demonstrate that its heat stress mitigation measures made the Singapore military ‘heat proof’. Secondly, the state shaped a soldier safety agenda in the late 2000s on the back of an increasing emphasis on safety and the transformation of the SAF into a highly-educated and technologically-sophisticated force. This meant a shift towards concern about the welfare of every soldier, particularly through the state’s drive to eradicate all training-related deaths. Accordingly, the SAF medical military leaders responded to the state’s safety agenda by introducing heat stress management research and policies that were oriented towards the target of eradicating deaths due to heat stress. This policy and research direction, as such, has been strongly guided by the state’s safety agenda and utilised to demonstrate to the public that all efforts have been taken to comprehensively mitigate the risks of heat.

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Asim, Muhammad, and Farooq Riaz Siddiqui. "Hybrid Nanofluids—Next-Generation Fluids for Spray-Cooling-Based Thermal Management of High-Heat-Flux Devices." Nanomaterials 12, no. 3 (February 1, 2022): 507. http://dx.doi.org/10.3390/nano12030507.

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In recent years, technical advancements in high-heat-flux devices (such as high power density and increased output performance) have led to immense heat dissipation levels that may not be addressed by traditional thermal fluids. High-heat-flux devices generally dissipate heat in a range of 100–1000 W/cm2 and are used in various applications, such as data centers, electric vehicles, microelectronics, X-ray machines, super-computers, avionics, rocket nozzles and laser diodes. Despite several benefits offered by efficient spray-cooling systems, such as uniform cooling, no hotspot formation, low thermal contact resistance and high heat transfer rates, they may not fully address heat dissipation challenges in modern high-heat-flux devices due to the limited cooling capacity of existing thermal fluids (such as water and dielectric fluids). Therefore, in this review, a detailed perspective is presented on fundamental hydrothermal properties, along with the heat and mass transfer characteristics of the next-generation thermal fluid, that is, the hybrid nanofluid. At the end of this review, the spray-cooling potential of the hybrid nanofluid for thermal management of high-heat-flux devices is presented.

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Alqahtani, Ali Ahmed, and Volfango Bertola. "Polymer and Composite Materials in Two-Phase Passive Thermal Management Systems: A Review." Materials 16, no. 3 (January 17, 2023): 893. http://dx.doi.org/10.3390/ma16030893.

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The application of polymeric and composite materials in two-phase passive heat transfer devices is reviewed critically, with a focus on advantages and disadvantages of these materials in thermal management systems. Recent technology developments led to an increase of the power density in several applications including portable electronics, space and deployable systems, etc., which require high-performance and compact thermal management systems. In this context, passive two-phase systems are the most promising heat transfer devices to dissipate large heat fluxes without external power supply. Usually, heat transfer systems are built with metals due to their excellent thermal properties. However, there is an increasing interest in replacing metallic materials with polymers and composites that can offer cost-effectiveness, light weight and high mechanical flexibility. The present work reviews state-of the-art applications of polymers and composites in two-phase passive thermal management systems, with an analysis of their limitations and technical challenges.

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Lin, Xiaohui, Songping Mo, Bingzhong Mo, Lisi Jia, Ying Chen, and Zhengdong Cheng. "Thermal management of high-power LED based on thermoelectric cooler and nanofluid-cooled microchannel heat sink." Applied Thermal Engineering 172 (May 2020): 115165. http://dx.doi.org/10.1016/j.applthermaleng.2020.115165.

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Chen, Yuanlong, Tingbo Hou, and Xiaochao Zhou. "Qualitative analysis of coupling effect of fluid velocity distribution in microchannels on the performance of the LED water cooling system." International Journal of Numerical Methods for Heat & Fluid Flow 29, no. 10 (October 7, 2019): 3893–907. http://dx.doi.org/10.1108/hff-06-2018-0288.

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Purpose The purpose of this paper is to ensure adequate thermal management to remove and dissipate the heat produced by a light-emitting diode (LED) and to guarantee reliable and safe operation. Design/methodology/approach A three-dimensional (3-D) computational fluid dynamics (CFD) model was used to analyze the distribution of fluid velocities among microchannels at four different aspect ratios. Findings The results showed that at the same inlet flow rate, the larger the aspect ratio of the microchannels, the better the uniformity of the internal fluid velocity and thus better the heat dissipation performance on the surface of the high-power LED chip. In addition, the thermal performance of a high-power LED water cooling system with four different aspect ratios’ microchannel structures is further studied experimentally. Specifically, the coupling effect between the fluid velocity distribution in the microchannels and the heat dissipation performance of a high-power LED water cooling system is qualitatively analyzed and compared with the simulation results of the fluid velocity distribution. The results fully demonstrated that a larger aspect ratio of the microchannels results in better heat dissipation performance on the surface of the high-power LED chip. Originality/value Optimizing the structural parameters to facilitate a relatively uniform velocity distribution to improve the water cooling system performance may be a key factor to be considered.

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Eldbari, ENG Moath Abdrabu, and Muhammad N Radhwi. "Energy Management Improving the Cooling System in a Local Factory." Budapest International Research in Exact Sciences (BirEx) Journal 1, no. 4 (October 27, 2019): 25–44. http://dx.doi.org/10.33258/birex.v1i4.475.

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Development is an ongoing process in all areas and this research studied of a cooling system for a local factory and evaluated to determine the efficiency and capacity of the cooling capacity of the factory at the desired level. ِAfter evaluating the cooling system and studying the case of the local factory, the heat gain loads in the factory was calculated internally and externally and found that there is a deficit in the cooling system by 45% and the suggestion is to improve the cooling system without affecting production or manpower. Accordingly, three points have been developed to improve the cooling system and the first point is reducing the heat gained from lighting by changing fluorescent bulbs by the LED and this step will reduce the heat gain from lighting by 64%. The second point is to reduce the volume space of production zones by installing the ceiling of the gypsum board where the height was reduced from eight to five meters, which reduced the heat gained by 37% from the walls. The third point is the installation of better insulation materials and has been proposed rock wool material for the roof and the material Rigid expanded board for walls and these materials have reduced 85% of the heat gain from the roof and 20% of the walls. The total rate of improvement in the cooling system completely (internal and external heat gain) is 25% or in other words, can be through the implementation of these points reduce cooling load by 25%.

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Prstic, Suzana, and Avram Bar-Cohen. "“Heat Shield”—An Enhancement Device for an Unshrouded, Forced Convection Heat Sink." Journal of Electronic Packaging 128, no. 2 (February 16, 2006): 172–76. http://dx.doi.org/10.1115/1.2188955.

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The inherent advantages of forced air cooling have led to the widespread use of fully and partially shrouded heat sinks for the thermal management of high power microprocessors. The superior thermal performance that is achievable in the fully shrouded configuration is accompanied by a significant pressure drop penalty. The concept introduced in the current study, employs a thin sheet-metal “heat shield,” placed around a partially shrouded heat sink, to channel the flow directly into the heat sink. A combined numerical and experimental study has shown that the use of this “heat shield” can substantially enhance heat sink thermal performance, in a channel geometry and air flow range typical of commercial chip packages; making it comparable to that of a fully shrouded heat sink, with a substantially lower pressure drop (∼50%). In addition, this thermal enhancement device can be easily retrofitted into existing systems; improving performance without major channel and/or fan modifications.

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Arik, Mehmet, Anant Setlur, Stanton Weaver, Deborah Haitko, and James Petroski. "Chip to System Levels Thermal Needs and Alternative Thermal Technologies for High Brightness LEDS." Journal of Electronic Packaging 129, no. 3 (April 9, 2007): 328–38. http://dx.doi.org/10.1115/1.2753958.

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Light emitting diodes (LEDs) historically have been used for indicators and produced low amounts of heat. The introduction of high brightness LEDs with white light and monochromatic colors has allowed them to penetrate specialty and general illumination applications. The increased electrical currents used to drive the LEDs have resulted in higher heat fluxes than those for average silicon integrated circuits (i.e., ICs). This has created a need to focus more attention on the thermal management engineering of LED power packages. The output of a typical commercial high brightness, 1mm2, LED has exceeded 100lm at drive levels approaching 3W. This corresponds to a heat flux of up to 300W∕cm2. Novel thermal solutions need to address system architectures, packaging, phosphors for light color conversion, and encapsulants and fillers for optical extraction. In this paper, the effect of thermal management on packaging architectures, phosphors, encapsulants, and system design are discussed. Additionally, discussions of microscopic defects due to packaging problems as well as chip active layer defects are presented through experimental and computational findings.

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Wan, Zhong Min, Zheng Kai Tu, and Jing Liu. "Performance Investigation on Porous Micro Heat Sink for Cooling of High Power LEDs." Advanced Materials Research 204-210 (February 2011): 1481–84. http://dx.doi.org/10.4028/www.scientific.net/amr.204-210.1481.

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A novel porous micro heat sink system is presented for thermal management of high power LEDs, which has high heat transport capability. Numerical model for the micro heat sink is developed to describe liquid flow and heat transfer based on the local thermal equilibrium of porous media, and it is solved with SIMPLE algorithm. The numerical results show that the heated surface temperature of porous micro heat sink is low at high heat fluxes and is much less than the bearable temperature level of LED chips. The heat transfer coefficient of heat sink is very high, and increasing the liquid velocity can enhance the average heat transfer coefficient. The overall pressure loss of heat sink system increases with the increasing the inlet velocity, but the overall pressure drop is much less than the pumping pressure provided by micro pump.

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Luo, Yi, Si Di Li, Zi Cheng Yu, and Xiao Dong Wang. "Improve the Performance of Micro Heat Pipe by Surface Modification." Applied Mechanics and Materials 868 (July 2017): 21–26. http://dx.doi.org/10.4028/www.scientific.net/amm.868.21.

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The appearance of high power LED has put forward higher requirements for thermal management. The micro heat pipe (MHP) has high heat transfer ability and plays an important role in high power LED and other high heat flux device cooling. In this paper, we designed and fabricated a micro heat pipe with fluoroalkyl silane (FAS) surface modified glass cover. The contact angle of the working area of glass cover reached 95.49° and made working fluid drops fall back to micro groove of silicon substrate more quickly. Thus the new glass cover can speed up the circulation of working fluid and enhance the heat transfer. The experimental results also proved that hydrophobic glass cover has a better heat transfer capability. Besides, this novel MHP reached the stable working status faster. When the input heat power was 10 W, the balance temperature of MHP with hydrophobic glass cover was 22 oC lower than traditional MHP, while the balance time is 58 seconds less. The work presented in this paper provides a new direction for optimize the MHP, not only the wick structure in substrate, but also the wettability of cover plate.

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Kaya, Mehmet. "Experimental Study on Active Cooling Systems Used for Thermal Management of High-Power Multichip Light-Emitting Diodes." Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/563805.

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The objective of this study was to develop suitable cooling systems for high-power multichip LEDs. To this end, three different active cooling systems were investigated to control the heat generated by the powering of high-power multichip LEDs in two different configurations (30 and 2 × 15 W). The following cooling systems were used in the study: an integrated multi-fin heat sink design with a fan, a cooling system with a thermoelectric cooler (TEC), and a heat pipe cooling device. According to the results, all three systems were observed to be sufficient for cooling high-power LEDs. Furthermore, it was observed that the integrated multifin heat sink design with a fan was the most efficient cooling system for a 30 W high-power multichip LED. The cooling system with a TEC and 46 W input power was the most efficient cooling system for 2 × 15 W high-power multichip LEDs.

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Joshi, P. S. "Comparison of finite volume and one dimensional network methodologies for thermal management of lighting applications." Journal of Physics: Conference Series 2116, no. 1 (November 1, 2021): 012022. http://dx.doi.org/10.1088/1742-6596/2116/1/012022.

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Abstract Signify is focused on building a state-of-the-art, innovative and sustainable solutions for industries, homes, buildings, and communities. In the last decade or so there has been a considerable shift from using traditional incandescent luminaires to highly efficient, cheaper, and robust LED (Light Emitting Diode) based lighting fixtures. LEDs are semiconductor devices and thus their life depends largely on operating temperatures. Thermal management of the lighting fixture, therefore, becomes crucial for the overall performance. Heat sinks are designed for given operating conditions for better thermal management. With the improved LED efficiencies there are two alternatives that the product designer can opt for namely, to increase the lumen output for the present fixture or to reduce the overall heat sink size. To assist the product designer in this aspect, the present paper reports the thermal management of lighting luminaries using two different modelling techniques such as Finite Volume Method (FVM) and One Dimensional (1D) resistive network analysis. These two modelling techniques are employed to predict the temperature profiles on the luminaire and then compared them with the actual test results. The processing time, accuracy, and method of implementation for both these techniques are then discussed.

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Hamidnia, Mohammad, Yi Luo, Xiaodong Wang, and Congming Li. "Experimental investigation on the thermal performance of Si micro-heat pipe with different cross-sections." Modern Physics Letters B 31, no. 30 (October 26, 2017): 1750279. http://dx.doi.org/10.1142/s0217984917502797.

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Increasing component densities of the integrated circuit (IC) and packaging levels has led to thermal management problems. Si substrates with embedded micro-heat pipes (MHPs) couple good thermal characteristics and cost savings associated with IC batch processing. The thermal performance of MHP is intimately related to the cross-sectional geometry. Different cross-sections are designed in order to enhance the backflow of working fluid. In this experimental study, three different Si MHPs with same hydraulic diameter and various cross-sections are fabricated by micro-fabrication methods and tested under different conditions of fluid charge ratios. The results show that the trapezoidal MHP associated with rectangular artery which is charged with 40% of vapor chamber’s volume has the best thermal performance. This silicon-based MHP is a passive approach for thermal management, which could widen applications in the commercial electronics industry and LED lightings.

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Kagel, Heike, Hannes Jacobs, Frank Bier, Jörn Glökler, and Marcus Frohme. "A Novel Microtiter Plate Format High Power Open Source LED Array." Photonics 6, no. 1 (February 25, 2019): 17. http://dx.doi.org/10.3390/photonics6010017.

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Many photochemical or photobiological applications require the use of high power ultraviolet light sources, such as high-pressure mercury arc lamps. In addition, many photo-induced chemical, biochemical and biological applications require either a combinatorial setting or a parallel assay of multiple samples under the same environmental conditions to ensure reproducibility. To achieve this, alternative, controllable light sources, such as ultraviolet light emitting diodes (UV LEDs) with high power and spatial control are required. Preferably, LEDs are arranged in a suitable standardized 96-well microtiter plate format. We designed such an array and established the methods required for heat management and enabling stable, controllable illumination over time.

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Wang, Cong, Won Sang Lee, and Nam Young Kim. "A Novel Silicon-Based Packaging Platform for High-Efficiency LED Modules." Advanced Materials Research 314-316 (August 2011): 359–63. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.359.

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A novel silicon-based packaging platform with the electroplated-based reflector and the electrode- guided interconnections is developed for the packaging component of a high-luminosity and high-efficiency multi-chip light-emitting diode (LED) module, which is patterned on a new type of insulating layer that consists of nanoporous anodized aluminum oxide (AAO) layer and plasma- enhanced chemical vapor deposition (PECVD) deposited silicon dioxide (SiO2) on a doped silicon substrate. The reflector and the electrical interconnections are successfully fabricated by using the electroplating method in the same body. In order to obtain the benefits of high efficiency LED modules, the requirements concerning thermal management and photomechanical layout have to be met. In this paper, we will discuss a novel fabrication method in LED module packaging platform, and then describe the thin layer of electroplated Cu/Ni/Au in order to reduce thermal resistance and to increase thermal diffusion efficiency. The heat generated by the LED chips is dissipated directly to the silicon body through the metal-plated platform, and truly excellent heat dissipation characteristics are observed. We demonstrate 987 lm 8 W-level cool-white light (5000 K, 16 V, 110 lm/W, CRI = 77) emission for 570 µm × 230 µm-chip LEDs at 600 mA operation.

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Esteves, Bruno M., Idalina J. Domingos, and Helena M. Pereira. "Pine wood modification by heat treatment in air." BioResources 3, no. 1 (January 5, 2008): 142–54. http://dx.doi.org/10.15376/biores.3.1.142-154.

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Maritime pine (Pinus pinaster) wood has low dimensional stability and durability. Heat treatment was made in an oven using hot air during 2 to 24 h and at 170-200 ºC. A comparison was made against steam heat treatment. The equilibrium moisture content and the dimensional stability (ASE) in radial and tangential directions were evaluated at 35%, 65%, and 85% relative humidity. MOE, bending strength and wettability were also determined. At the same mass loss, improvements of equilibrium moisture content and dimensional stability were higher for oven heat treatment, but the same was true for mechanical strength degradation. A 50% decrease in hemicellulose content led to a similar decrease in bending strength.

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Stamponi, Ettore, Francesco Giorgini, Franco Cotana, and Elisa Moretti. "Preliminary assessment of a microgrid integrated with a biomass gasification CHP system for a production facility in Central Italy." E3S Web of Conferences 238 (2021): 01012. http://dx.doi.org/10.1051/e3sconf/202123801012.

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The aim to reduce carbon dioxide emissions and to improve buildings energy efficiency has led to develop smart grids to manage electricity and heat. The work deals with the thermal and electric microgrid analysis of the Loccioni Company: the production facility consists of high-energy performance industrial and office buildings, partially powered by produced on-site renewable energy (solar PV, hydropower plants, water ground heat pumps). The challenge of continuous improvement in the use of energy led the company to develop a thermal microgrid for optimal management of the heat produced by a small-scale CHP system (50 kWel/110 kWth). The cogeneration system is based on biomass (pellet) chemical degradation process of gasification. The work discusses preliminary results relating to the first months of the system operation, to highlight the energy benefits and the critical issues. Data are collected by the Company monitoring system and a laboratory feedstock physico-chemical characterization is carried out. The main goal of this paper is to lay the foundations for the development of an energy management system that regulates energy flows between buildings. The development of the thermal microgrid will guarantee not only tangible benefits in terms of energy savings but also an increase in the resilience of the entire building/plant system.

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Jung, Jongjin. "Lifespan Characteristics of SMD-Type LED Exit Lights." Journal of the Korean Society of Hazard Mitigation 21, no. 2 (April 30, 2021): 59–64. http://dx.doi.org/10.9798/kosham.2021.21.2.59.

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In this study, the electrical characteristics of SMD-type LED light sources, which have been used for most exit lights since 2007, were analyzed. The relationship between the electrical characteristics of the LED light source and the life of the light source was analyzed. An LED exit light that used a top-view LED and a power LED was used for this experiment. The sizes of the exit lights were medium and small. In addition, the electrical characteristics of the LED light source were analyzed by measuring the input current, light source current, and power values related to the life of the LED. As a result, when the exit lights were of the same size, the top-view LED exit light required less power and lower current than the power LED exit light, and the current and power waveforms were also good. It was also confirmed that the power LED exit light was out of the range of rated power for some samples. Therefore, when developing an LED exit light, checking the voltage, current, power, and heat dissipation of the light source together will improve product quality and future management.

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Journal articles on the topic 'LED heat management'

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