scholarly journals Влияние условий теплоотвода на характеристики концентраторных фотоэлектрических модулей

2018 ◽  
Vol 52 (3) ◽  
pp. 390
Author(s):  
А.В. Андреева ◽  
Н.Ю. Давидюк ◽  
Д.А. Малевский ◽  
А.Н. Паньчак ◽  
Н.А. Садчиков ◽  
...  
Keyword(s):  
Solar Cells ◽  
Heat Dissipation ◽  
Surrounding Medium ◽  
Forward Bias ◽  
Thermal Characteristics ◽  
Heat Removal ◽  
Heat Sinks ◽  
Thermal Processes ◽  
Voltage Drops ◽  
Fresnel Lenses

AbstractThe results of studying the effect of various conditions of heat dissipation on heating and temperature distribution in components of concentrator photovoltaic modules are reported. The modules based on Fresnel lenses and triple-junction solar cells InGaP/GaAs/Ge mounted on copper and steel heat sinks are studied. In order to determine the thermal characteristics, we use a method, which makes it possible to measure the temperature of the p–n junctions in the solar cells under laboratory conditions upon the simulation of thermal processes arising in the course of operation of the module under typical conditions. Further, the above temperature is used to calculate the value of the thermal resistance for a system consisting of a solar cell and the surrounding medium. The thermal processes in the module are simulated by transferring current through the solar cells in the forward-bias direction. The value of heating of the solar cells is determined by comparing the forward-voltage drops measured at the time of its rapid application or switching-off under various conditions of heat removal. The conditions of heat removal are varied using the generator’s air flow.

Imminent Needs in Future Development of Air Cooled Microprocessors Heat Sinks

2010 ◽  
Vol 2010 (1) ◽  
pp. 000434-000439
Author(s):  
V. Ganescu ◽  
A. Pascu
Keyword(s):  
Heat Dissipation ◽  
Heat Removal ◽  
Leading Edge ◽  
Ambient Air ◽  
Heat Sinks ◽  
System Level ◽  
Air Cooling ◽  
Cfd Simulations ◽  
Constant Heat ◽  
Laminar Convection

This study reiterates the fact that revolutionary heat sink geometries, materials and overall exponentially higher performing alternatives are continuously and highly needed as applied to the air cooling of a typical computer system microprocessor. Attention was focused on forced convection regimes of operation and from a system level approach. Minor improvements in the performance of air cooled microprocessor heat sinks via typical small design improvements are discussed. Laminar convection and constant heat dissipation were looked at. The CFD simulations exemplified were completed for several power levels and ambient air characterized by a Pr = 0.71. The numerical results presented coincided in large with the experimentally derived documented data. In conclusion, the authors stress the fact that leading-edge alternatives in air-cooled heat removal of such applications are imperiously necessary.

CPV Modules Based on Lens Panels

2010 ◽  
Vol 74 ◽  
pp. 211-218 ◽  
Author(s):  
V.D. Rumyantsev ◽  
Yu.V. Ashcheulov ◽  
N.Yu. Davidyuk ◽  
E.A. Ionova ◽  
P.V. Pokrovskiy ◽  
...  
Keyword(s):  
Solar Cells ◽  
Heat Dissipation ◽  
Fresnel Lens ◽  
Test Method ◽  
Glass Sheet ◽  
Ir Absorption ◽  
Back Side ◽  
High Concentration ◽  
Small Aperture ◽  
Fresnel Lenses

A work on development of the high concentration photovoltaic (HCPV) modules with Fresnel lens panels and III-V multijunction cells is presented. A composite structure of the small-aperture area 40x40 (or 60x60) mm2 Fresnel lenses, united in a panel, was realized. A silicate glass sheet (front side of a module) serves as a superstrate for transparent microprisms formed in silicone. Small averaged thickness of the prisms ensures low IR absorption of sunlight in comparison with acrylic Fresnel lenses. Temperature dependences of the optical properties in such a type of the solar concentrators and PV properties of the cells in passive heat dissipation conditions are under consideration. The solar cells are the triple-junction InGaP/(In)GaAs/Ge cells with designated illumination area 1.7-2.3 mm in diameter. A HCPV module consists of the 144 (or 64) sub-modules in 12x12 (or 8x8) configuration. Solar cells are protected from environment in different ways: by side walls of a module body, or by a rear glass sheet at integrated sealing the cells in a back-side module panel. Module design includes refractive smooth-surface secondary lenses. The cell strings are glued to the rear glass surface of the module body using lamination process. Proper quality of the solar cells in a multistage module assembling procedure is ensured owing to specially developed contactless test method, based on analyzing the electroluminescent signals at local photoexitation. For arrangement of the HCPV modules in a solar installation, a number of the solar trackers have been developed and realized for 1-3-5 kWp of the installed power.

Operational Temperature Ranges in Pulsating Heat Pipes

2012 ◽  
Author(s):  
Nick Hansen ◽  
Gregory J. Michna
Keyword(s):  
Steady State ◽  
Heat Input ◽  
Heat Dissipation ◽  
Heat Removal ◽  
Electronics Cooling ◽  
Heat Sinks ◽  
Pulsating Heat Pipe ◽  
Evaporator Temperature ◽  
Condenser Temperature ◽  
Temperature Ranges

The pulsating heat pipe (PHP), due to its ability to dissipate large amounts of heat and reduce temperature nonuniformity, is a promising technology for electronics cooling applications. In this work, the effect of the direction of change of heat dissipation rate in a PHP was explored. A quasi-steady state was approached by either increasing or reducing the evaporator heat input rate to a given level. It was found that instead of reaching a single steady-state evaporator temperature for a given heat input and condenser temperature, there is a range within which the evaporator temperature will fluctuate. Since most electronics cooling applications will have a non-steady heat removal requirement, understanding this phenomenon is of great importance for the design of PHP heat sinks.

scholarly journals Influence of Ambient Temperature on Radiative and Convective Heat Dissipation Ratio in Polymer Heat Sinks

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2286
Author(s):  
Jan Kominek ◽  
Martin Zachar ◽  
Michal Guzej ◽  
Erik Bartuli ◽  
Petr Kotrbacek
Keyword(s):  
Heat Transfer ◽  
Ambient Temperature ◽  
Convective Heat ◽  
Heat Dissipation ◽  
High Surface ◽  
Heat Sinks ◽  
Fourth Power ◽  
Molding Process ◽  
Ambient Temperatures ◽  
University Of Technology

Miniaturization of electronic devices leads to new heat dissipation challenges and traditional cooling methods need to be replaced by new better ones. Polymer heat sinks may, thanks to their unique properties, replace standardly used heat sink materials in certain applications, especially in applications with high ambient temperature. Polymers natively dispose of high surface emissivity in comparison with glossy metals. This high emissivity allows a larger amount of heat to be dissipated to the ambient with the fourth power of its absolute surface temperature. This paper shows the change in radiative and convective heat transfer from polymer heat sinks used in different ambient temperatures. Furthermore, the observed polymer heat sinks have differently oriented graphite filler caused by their molding process differences, therefore their thermal conductivity anisotropies and overall cooling efficiencies also differ. Furthermore, it is also shown that a high radiative heat transfer leads to minimizing these cooling efficiency differences between these polymer heat sinks of the same geometry. The measurements were conducted at HEATLAB, Brno University of Technology.

Thermal Behaviors of Passively-Cooled Hybrid Fin Heat Sinks for Lightweight and High Performance Thermal Management

2015 ◽  
Author(s):  
Nico Setiawan Effendi ◽  
Kyoung Joon Kim
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
High Performance ◽  
Heat Dissipation ◽  
Computational Study ◽  
Heat Sinks ◽  
Channel Diameter ◽  
Internal Channel ◽  
Study Results ◽  
Parametric Effects

A computational study is conducted to explore thermal performances of natural convection hybrid fin heat sinks (HF HSs). The proposed HF HSs are a hollow hybrid fin heat sink (HHF HS) and a solid hybrid fin heat sink (SHF HS). Parametric effects such as a fin spacing, an internal channel diameter, a heat dissipation on the performance of HF HSs are investigated by CFD analysis. Study results show that the thermal resistance of the HS increases while the mass-multiplied thermal resistance of the HS decreases associated with the increase of the channel diameter. The results also shows the thermal resistance of the SHF HS is 13% smaller, and the mass-multiplied thermal resistance of the HHF HS is 32% smaller compared with the pin fin heat sink (PF HS). These interesting results are mainly due to integrated effects of the mass-reduction, the surface area enhancement, and the heat pumping via the internal channel. Such better performances of HF HSs show the feasibility of alternatives to the conventional PF HS especially for passive cooling of LED lighting modules.

scholarly journals Mechanisms of charge accumulation in the dark operation of perovskite solar cells

2016 ◽  
Vol 18 (22) ◽  
pp. 14970-14975 ◽  
Author(s):  
Teresa S. Ripolles ◽  
Ajay K. Baranwal ◽  
Koji Nishinaka ◽  
Yuhei Ogomi ◽  
Germà Garcia-Belmonte ◽  
...  
Keyword(s):  
Solar Cells ◽  
Dark Current ◽  
Forward Bias ◽  
Perovskite Solar Cells ◽  
Charge Accumulation ◽  
Current Voltage

In this work, a new current peak at forward bias in the dark current–voltage curves has been identified for standard mesoscopic perovskite solar cells.

Stacked Microchannel Heat Sinks for Liquid Cooling of Microelectronic Components

2000 ◽  
Author(s):  
X. Wei ◽  
Y. Joshi
Keyword(s):  
Flow Rate ◽  
Heat Sink ◽  
Water Flow Rate ◽  
Heat Removal ◽  
Single Layer ◽  
Heat Sinks ◽  
Computationally Efficient ◽  
Liquid Cooling ◽  
Number Of Layers ◽  
Microelectronic Components

Abstract A novel heat sink based on a multi-layer stack of liquid cooled microchannels is investigated. For a given pumping power and heat removal capability for the heat sink, the flow rate across a stack of microchannels is lower compared to a single layer of microchannels. Numerical simulations using a computationally efficient multigrid method [1] were carried out to investigate the detailed conjugate transport within the heat sink. The effects of the microchannel aspect ratio and total number of layers on thermal performance were studied for water as coolant. A heat sink of base area 10 mm by 10 mm with a height in the range 1.8 to 4.5 mm (2–5 layers) was considered with water flow rate in the range 0.83×10−6 m3/s (50 ml/min) to 6.67×10−6 m3/s (400 ml/min). The results of the computational simulations were also compared with a simplified thermal resistance network analysis.

scholarly journals Effect of perspired moisture and material properties on evaporative cooling and thermal protection of the clothed human body exposed to radiant heat

2018 ◽  
Vol 89 (18) ◽  
pp. 3663-3676 ◽  
Author(s):  
Manhao Guan ◽  
Agnes Psikuta ◽  
Martin Camenzind ◽  
Jun Li ◽  
Sumit Mandal ◽  
...  
Keyword(s):  
Human Body ◽  
Material Properties ◽  
Heat Dissipation ◽  
Thermal Protection ◽  
Evaporative Cooling ◽  
Thermal Characteristics ◽  
Radiant Heat ◽  
Physiological Effect ◽  
Heat Gain ◽  
Active Liquid

Perspired moisture plays a crucial role in the thermal physiology and protection of the human body wearing thermal protective clothing. Until now, the role of continuous sweating on heat transfer, when simultaneously considering internal and external heat sources, has not been well-investigated. To bridge this gap, a sweating torso manikin with 12 thermal protective fabric systems and a radiant heat panel were applied to mimic firefighting. The results demonstrated how the effect of radiant heat on heat dissipation interacted with amount of perspired moisture and material properties. A dual effect of perspired moisture was demonstrated. For hydrophilic materials, sweating induced evaporative cooling but also increased radiant heat gain. For hydrophilic station uniforms, the increment of radiant heat gain due to perspired moisture was about 11% of the increase of heat dissipation. On the other hand, perspired moisture can increase evaporative cooling and decrease radiant heat gain for hydrophobic materials. In addition to fabric thermal resistance ( Rct) and evaporative resistance ( Ret), material hydrophilicity and hydrophobicity, emissivity and thickness are important when assessing metabolic heat dissipation and radiant heat gain with profuse sweating under radiant heat. The results provide experimental evidence that Rct and Ret, the general indicators of the clothing thermo-physiological effect, have limitations in characterizing thermal comfort and heat strain during active liquid sweating in radiant heat. This paper offers a more complete insight into clothing thermal characteristics and human thermal behaviors under radiant heat, contributing to the accurate evaluation of thermal stress for occupational and general individuals.

Design of Optimum Plate-Fin Natural Convective Heat Sinks

2003 ◽  
Vol 125 (2) ◽  
pp. 208-216 ◽  
Author(s):  
Avram Bar-Cohen ◽  
Madhusudan Iyengar ◽  
Allan D. Kraus
Keyword(s):  
Nusselt Number ◽  
Specific Heat ◽  
Rectangular Plate ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Thermal Design ◽  
Heat Sinks ◽  
And Performance ◽  
Nusselt Number Correlation ◽  
The Impact

The effort described herein extends the use of least-material single rectangular plate-fin analysis to multiple fin arrays, using a composite Nusselt number correlation. The optimally spaced least-material array was also found to be the globally best thermal design. Comparisons of the thermal capability of these optimum arrays, on the basis of total heat dissipation, heat dissipation per unit mass, and space claim specific heat dissipation, are provided for several potential heat sink materials. The impact of manufacturability constraints on the design and performance of these heat sinks is briefly discussed.

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