scholarly journals A Luminous Efficiency-Enhanced Laser Lighting Device with a Micro-Angle Tunable Filter to Recycle Unconverted Blue Laser Rays

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1144
Author(s):  
Xinrui Ding ◽  
Ruixiang Qian ◽  
Liang Xu ◽  
Zongtao Li ◽  
Jiasheng Li ◽  
...  
Keyword(s):  
Heat Dissipation ◽  
High Energy ◽  
Luminous Flux ◽  
Tunable Filter ◽  
Blue Laser ◽  
High Energy Density ◽  
Color Temperature ◽  
Maximum Temperature ◽  
Lighting Device ◽  
Laser Rays

In this work, a phosphor converter with small thickness and low concentration, based on a micro-angle tunable tilted filter (ATFPC), was proposed for hybrid-type laser lighting devices to solve the problem of silicone phosphor converters’ carbonizing under high-energy density. Taking advantage of the filter and the scattering characteristics of microphosphors, two luminous areas are generated on the converter. Compared with conventional phosphor converters (CPCs), the lighting effects of ATFPCs are adjustable using tilt angles. When the tilt angle of the micro filter is 20°, the luminous flux of the ATPFCs is increased by 11.5% at the same concentration; the maximum temperature (MT) of ATFPCs is reduced by 22.8% under the same luminous flux and the same correlated color temperature (CCT) 6500 K. This new type of lighting device provides an alternative way to improve the luminous flux and heat dissipation of laser lighting.

A Ventilation Cooling Solution to Improve Thermal Environment of High Energy Density Li-Ion Battery Packs

2015 ◽  
Author(s):  
Zhiqiang Li ◽  
Xiaowei Fan ◽  
Fang Wang ◽  
Dasi He ◽  
Shifei Wei
Keyword(s):  
Energy Density ◽  
Thermal Environment ◽  
High Energy ◽  
High Energy Density ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Li Ion Battery ◽  
Battery System ◽  
Li Ion ◽  
Battery Cells

This paper focuses on the cooling solution to a high energy density and large capacity Li-ion battery system which consist of four packs of 26650 cells. The cooling measure is a critical technology for many Li-ion battery systems especially that designed for hybrid electric vehicles, in which, high energy density within a limited space is very common in these systems. Both the safety and efficiency of Li-ion battery cells rely on the temperature which is under control of the battery thermal management system. In this study, temperature fields within battery boxes are simulated with the computational fluid dynamic (CFD) method. With the help of an airconditioner, a cooling solution is proposed for a relatively large dimensional, high energy density Li-ion battery cells array using by vehicles. Through the proposed solution, the maximum single-cell temperature is restricted to a reasonable level, and the maximum temperature difference throughout the battery system is also improved.

scholarly journals Optimization of Air-cooling System for a Lithium-ion Battery Pack

2021 ◽  
Vol 321 ◽  
pp. 02018
Author(s):  
Sungwook Jin ◽  
Min-Sik Youn ◽  
Youn-Jea Kim
Keyword(s):  
Power Plants ◽  
Cooling System ◽  
Lithium Ion ◽  
High Energy ◽  
High Energy Density ◽  
Optimization Process ◽  
Maximum Temperature ◽  
Design Parameters ◽  
Air Cooling ◽  
Battery Cells

Lithium-ion batteries have been used as energy storage technologies for electric vehicles or power plants due to their high energy density, low self-discharge rate, and long lifespan. Since the temperature of the batteries are directly related with their durability, distributing the temperature uniformly and efficiently is critically important. In this study, a technology using forced convection with air was implemented to remove heat of the battery cells inside a package. The performance of the cooling system was evaluated by changing the gap distance between the battery cells and the configurations of the air channel. In order to improve the cooling performance of the battery, the shape of the battery module was optimized. To begin the optimization process, a sensitivity analysis was conducted to analyze the influence of the design parameters on the battery performance. Based on the result from the analysis, an optimization process was performed to determine an optimum channel design. As a result of the optimization, a battery cell package with the lowest maximum temperature and a minimum deviation between the temperature in between each cell was selected.

SCALING LAWS OF STRUCTURE-BASED OPTICAL ACCELERATORS

2007 ◽  
Vol 22 (22) ◽  
pp. 3898-3911
Author(s):  
AMIT MIZRAHI ◽  
VADIM KARAGODSKY ◽  
LEVI SCHÄCHTER
Keyword(s):  
Electric Fields ◽  
Scaling Laws ◽  
Heat Dissipation ◽  
Single Mode ◽  
High Energy ◽  
High Energy Density ◽  
Great Promise ◽  
Efficient System ◽  
Stringent Constraint ◽  
Low Efficiency

A structure-based laser accelerator harnesses technological progress developed by the laser and optical fiber industries, potentially facilitating a compact and efficient system. In the optical regime, dielectrics sustain higher electric fields and gradients of the order of a few GV/m may become available, but the acceleration structures are different than those used in the microwave regime. Various dielectric structures have been analyzed, and from the pure accelerator parameters perspective (gradient, interaction impedance, group velocity, wake-fields), their performance is of great promise. Operation similar to current linear accelerators may lead to a prohibitively low efficiency. Therefore, including a feedback attached to each module may improve the efficiency from a few percents to higher than 90% – in fact, the efficiency is limited only by the constraints on the stability of the optical system. Single mode operation in the optical regime imposes that at least one of the dimensions of each micro-bunch ought to be sub-micronic leading to a stringent constraint on the emittance and thus on the luminosity. Attempting to increase the latter, imposes high energy density in the vacuum tunnel as well as in its adjacent dielectric layer(s). This, in turn, is bounded by the maximum stress, temperature increase and heat dissipation, dielectrics can sustain at these scales.

CONSTRAINTS ON STRUCTURE-BASED OPTICAL ACCELERATORS

2007 ◽  
Vol 21 (03n04) ◽  
pp. 331-342
Author(s):  
AMIT MIZRAHI ◽  
VADIM KARAGODSKY ◽  
LEVI SCHÄCHTER
Keyword(s):  
Electric Fields ◽  
Heat Dissipation ◽  
Single Mode ◽  
High Energy ◽  
High Energy Density ◽  
Great Promise ◽  
Linear Accelerators ◽  
Efficient System ◽  
Stringent Constraint ◽  
Low Efficiency

A structure-based laser accelerator harnesses technological progress developed by the laser and optical fiber industries, potentially facilitating a compact and efficient system. In the optical regime, dielectrics sustain higher electric fields and gradients of the order of a few GV/m may become available, but the acceleration structures are different than those used in the microwave regime. Various dielectric structures have been analyzed, and from the pure accelerator parameters perspective (gradient, interaction impedance, group velocity, wake-fields), their performance is of great promise. Operation similar to current linear accelerators may lead to a prohibitively low efficiency. Therefore, including a feedback attached to each module may improve the efficiency from a few percents to higher than 90% – in fact, the efficiency is limited only by the constraints on the stability of the optical system. Single mode operation in the optical regime imposes that at least one of the dimensions of each micro-bunch ought to be sub-micronic leading to a stringent constraint on the emittance and thus on the luminosity. Attempting to increase the latter, imposes high energy density in the vacuum tunnel as well as in its adjacent dielectric layer(s). This, in turn, is bounded by the maximum stress, temperature increase and heat dissipation, dielectrics can sustain at these scales.

scholarly journals Optimization of Helium Inflating on Heat Dissipation and Luminescence Properties of the A60 LED Filament Lamps

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Yizhan Chen ◽  
Qingguang Zeng ◽  
Lite Zhao ◽  
Yuanxing Li ◽  
Guangyao Huang ◽  
...  
Keyword(s):  
Heat Dissipation ◽  
Cost Effective ◽  
High Heat ◽  
Luminous Flux ◽  
Junction Temperature ◽  
Color Temperature ◽  
Filament Lamp ◽  
High Heat Transfer ◽  
High Heat Transfer Coefficient ◽  
Filament Lamps

LED filament lamp has the characteristics of nearly 360° lighting angle, high brightness, and low energy consumption, turning it gradually into the best substitute for traditional incandescent lamps. At present, due to the limitations of heat dissipation, the development of high-power LED filament lamp is restricted. Helium is a rare gas with small density and high heat transfer coefficient. It can be used as a cooling and protective gas for LED filament lamp. In this paper, we investigated the effects of helium on the heat dissipation and luminescence performance of the A60 LED filament lamps by detecting the changes of junction temperature, color temperature, and luminous flux of different ratios helium inflating in the different power A60 LED filament lamps. Through the experiment, we found the most cost-effective ratio of helium gas in the A60 LED filament lamps without improving the lamp size and the filament diameter.

Pilot-scale combustion studies with kraft lignin in a powder burner and a CFB boiler

TAPPI Journal ◽  
2010 ◽  
Vol 9 (6) ◽  
pp. 24-30 ◽  
Author(s):  
NIKLAS BERGLIN ◽  
PER TOMANI ◽  
HASSAN SALMAN ◽  
SOLVIE HERSTAD SVÄRD ◽  
LARS-ERIK ÅMAND
Keyword(s):  
Circulating Fluidized Bed ◽  
Black Liquor ◽  
Chloride Content ◽  
Pilot Scale ◽  
High Energy ◽  
Kraft Lignin ◽  
High Energy Density ◽  
Alkali Chloride ◽  
Cfb Boiler ◽  
Solid Biofuel

Processes have been developed to produce a solid biofuel with high energy density and low ash content from kraft lignin precipitated from black liquor. Pilot-scale tests of the lignin biofuel were carried out with a 150 kW powder burner and a 12 MW circulating fluidized bed (CFB) boiler. Lignin powder could be fired in a powder burner with good combustion performance after some trimming of the air flows to reduce swirl. Lignin dried to 10% moisture content was easy to feed smoothly and had less bridging tendencies in the feeding system than did wood/bark powder. In the CFB boiler, lignin was easily handled and cofired together with bark. Although the filter cake was broken into smaller pieces and fines, the combustion was not disturbed. When cofiring lignin with bark, the sulfur emission increased compared with bark firing only, but most of the sulfur was captured by calcium in the bark ash. Conventional sulfur capture also occurred with addition of limestone to the bed. The sulfur content in the lignin had a significantly positive effect on reducing the alkali chloride content in the deposits, thus reducing the high temperature corrosion risk.

A HIGH ENERGY DENSITY ZINC/OXYGEN BATTERY SYSTEM

1966 ◽  
Author(s):  
S. CHODOSH ◽  
E. KATSOULIS ◽  
M. ROSANSKY
Keyword(s):  
Energy Density ◽  
High Energy ◽  
High Energy Density ◽  
Battery System

Efficient Co-Harvesting of Solar Energy and Low-Grade Heat by Molecular Photoswitches for High Energy Density, Long-Term Stable Solar Thermal Battery

2019 ◽  
Author(s):  
Zhao-Yang Zhang ◽  
Tao LI
Keyword(s):  
Energy Density ◽  
Solar Energy ◽  
High Performance ◽  
High Energy ◽  
Solar Thermal ◽  
High Energy Density ◽  
Low Grade ◽  
Thermal Battery ◽  
Low Grade Heat

Solar energy and ambient heat are two inexhaustible energy sources for addressing the global challenge of energy and sustainability. Solar thermal battery based on molecular switches that can store solar energy and release it as heat has recently attracted great interest, but its development is severely limited by both low energy density and short storage stability. On the other hand, the efficient recovery and upgrading of low-grade heat, especially that of the ambient heat, has been a great challenge. Here we report that solar energy and ambient heat can be simultaneously harvested and stored, which is enabled by room-temperature photochemical crystal-to-liquid transitions of small-molecule photoswitches. The two forms of energy are released together to produce high-temperature heat during the reverse photochemical phase change. This strategy, combined with molecular design, provides high energy density of 320-370 J/g and long-term storage stability (half-life of about 3 months). On this basis, we fabricate high-performance, flexible film devices of solar thermal battery, which can be readily recharged at room temperature with good cycling ability, show fast rate of heat release, and produce high-temperature heat that is >20<sup> o</sup>C higher than the ambient temperature. Our work opens up a new avenue to harvest ambient heat, and demonstrate a feasible strategy to develop high-performance solar thermal battery.

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