Characteristics of heat dissipation from photovoltaic cells on the bottom wall of a horizontal cabinet to ambient natural convective air stream

Energy ◽  
2011 ◽  
Author(s):  
Y.L. Tsay ◽  
J.C. Cheng ◽  
H.F. Hong ◽  
Z.H. Shih
Keyword(s):  
Heat Dissipation ◽  
Photovoltaic Cells ◽  
Bottom Wall ◽  
Air Stream

Characteristics of Heat Dissipation from a Block Heat Source Module in a Three-Dimensional Cabinet to Ambient Natural Convective Air Stream

2012 ◽  
Vol 229-231 ◽  
pp. 2589-2592
Author(s):  
Y.L. Tsay ◽  
J.C. Cheng
Keyword(s):  
Natural Convection ◽  
Rayleigh Number ◽  
Heat Source ◽  
Heat Dissipation ◽  
Three Dimensional ◽  
Thermal Interaction ◽  
Air Stream ◽  
Conjugate Conduction ◽  
Air Streams ◽  
Thermal Conductivities

This study combined the numerical analysis and experimental measurement to investigate the conjugate conduction and natural convection for a block heat source module in a three-dimensional cabinet filled and surrounded by air. The effects of Rayleigh number Ra, module position C1, ratio of block to air thermal conductivities Kbf, and ratio of board to air thermal conductivities Kpf are examined. Moreover, efforts are carried out to explore the influence of thermal interaction between the air streams inside and outside the cabinet.

scholarly journals Cooling Effect Efficiency Prediction of Aluminum Dimples Block using DOE Technique

2018 ◽  
Vol 7 (4.30) ◽  
pp. 152
Author(s):  
Ganesan H. N ◽  
Kasim M. S ◽  
Izamshah R ◽  
Anand T.J. S ◽  
Hafiz M. S. A ◽  
...  
Keyword(s):  
Heat Dissipation ◽  
Orientation Angle ◽  
Cooling Time ◽  
Cooling Effect ◽  
Average Error ◽  
Stream Velocity ◽  
Air Stream ◽  
Enhancement Method ◽  
Air Flow Velocity ◽  
The Mathematical Model

The main aim of the present work is to study the effect of heat enhancement method on the cooling process of a spherical dimple profile. It was prominently known that introducing dimples configuration causes an enhancement in heat transfer over a surface. In this project, an experimental investigation was carried out to examine the cooling effect of the spherical dimple profile during steady laminar flow in a wind tunnel. Seventeen different sets of parameters related to dimple diameter (mm), dimple orientation (angle) and air stream velocity (m/s) were studied. The Box-Behnken of Response Surface Methodology (RSM) was used as design of experiments (DoE) tool to evaluate these parameters on cooling time. This work deals with the analysis of variance (ANOVA) in order to establish the significant effect of input parameters. The result reveals that an increase in dimple diameter and air stream velocity increase heat dissipation. The shortest cooling time of 7 minutes can be achieved when the dimple diameter is 12 mm; the dimple orientation is 60° and air flow velocity at 18 m/s. The mathematical model has been rendered where the model has been experimentally validated with the average error of 6%.

Effect of a Shield on Mixed Convection in a Rectangular Enclosure with Moving Cold Sidewalls and a Heat Source on the Bottom Wall

2010 ◽  
Vol 297-301 ◽  
pp. 584-589
Author(s):  
Ghanbar Ali Sheikhzadeh ◽  
S.H. Musavi ◽  
N. Sadoughi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Source ◽  
Transfer Coefficient ◽  
Heat Dissipation ◽  
Bottom Wall ◽  
Governing Equations ◽  
Thermal Shield ◽  
The Heat Transfer Coefficient ◽  
Specific Distance

In this work, the mixed convention of air inside a rectangular cavity with moving cold sidewalls is studied numerically. A constant flux heat source is attached to the bottom wall of the cavity. A thin thermal shield is located at a specific distance above the heat source. The governing equations are solved using appropriate numerical methods. A parametric study has been conducted and the effects of heat source length, its location and the shield distance from the source on the heat transfer have been investigated. The results show that the heat dissipation increases as the heat source and the shield are moved up to a certain distance towards either sidewall. However, moving them beyond this limiting distance results in the reduction of heat dissipation. It is shown that the presence of shield results in the reduction of the heat transfer coefficient. However, for the normalized distance of the shield from the heat source greater than , the shield’s effect on the reduction of the heat transfer coefficient is less than.

scholarly journals Effect of the addition of pie-shaped ribs and parallelogram ribs in micro-channels on thermal performance using diamond-water nanofluid

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Kamel Chadi ◽  
Nourredine Belghar ◽  
Belhi Guerira ◽  
Mohammed Lachi ◽  
Mourad Chikhi
Keyword(s):  
Heat Dissipation ◽  
Constant Heat Flux ◽  
Three Dimensions ◽  
Bottom Wall ◽  
Micro Channel ◽  
Thermal Exchange ◽  
Fourth Case ◽  
Exchange Performance ◽  
Micro Channels ◽  
Lower Temperature

AbstractIn this paper, we numerically study the influence of the addition of parallelogram ribs and pie-shaped ribs in micro-channels on thermal exchange in three dimensions. We design four different silicon micro-channel heat sinks; the first and second cases without ribs, the third case with added pie-shaped ribs, and a fourth case containing parallelogram ribs. The main purpose of this research is to determine the best micro-channel heat sink in which the heat dissipation is sufficient to improve the heat exchange performance of the micro-channel, as well as to improve the cooling of the electronic components. A constant heat flux is applied to the bottom wall of the four micro-channels, and we use liquid diamond-water with a volume concentration of 5% diamond nanoparticles as a coolant, with a Reynolds number chosen between 200 and 600. The numerical results show that the Nusselt number (Nu) of the micro-channel that contains the parallelogram ribs is higher than that for the other cases, and it also yiels lower temperature values on the bottom wall of the substrate compared to the micro-channel containing pie ribs. When increasing the flow velocity, the thermal resistance of the micro-channel decreases in all cases, and we then find the largest value of the friction factor in the fourth case (with parallelogram ribs).

THE COOLING POWER OF THE PIGEON HEAD

1994 ◽  
Vol 194 (1) ◽  
pp. 329-339 ◽  
Author(s):  
R St-Laurent ◽  
J Larochelle
Keyword(s):  
Wind Speed ◽  
Heat Dissipation ◽  
Buccal Cavity ◽  
Resting Metabolic Rate ◽  
Cooling Power ◽  
Evaporative Heat Loss ◽  
Body Temperatures ◽  
Air Stream ◽  
Beak Opening ◽  
Stable Core

Resting pigeons preheated to a stable core temperature of 43.2 °C, which is within the range of body temperatures recorded during flight, were able to cool their body at high rates if their head and upper neck were exposed to an air stream at 23.5 °C. The heat dissipation capacity of the head and neck, estimated from measurements made at a wind speed (100 km h-1) corresponding to fast flight, was 9.8 W, or 4.5 times the resting heat production. Since the greater part of this capacity, about 8 W, was attributable to the inner surfaces of the mouth, ram ventilation of the buccal cavity appears to be an important mechanism for increasing evaporative heat loss during flight. Accordingly, wind-assisted mouth cooling should be utilized by resting pigeons, since exposure to a slight breeze (approximately 10 km h-1) could augment their dissipating power by an amount equivalent to their resting metabolic rate. It is concluded that beak opening, together with a source of convection other than panting and gular flutter, is required to exploit fully the heat dissipation capacity of the buccopharyngeal mucosa of birds.

scholarly journals Heat transfer enhancement of wall with a near wall cylinder in a channel at low and middle Reynolds number ranges

2020 ◽  
pp. 002029402096212
Author(s):  
Hui Xu ◽  
Yixi Cai ◽  
Guannan Xi
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Heat Transfer Enhancement ◽  
Heat Dissipation ◽  
Vortical Structure ◽  
Bottom Wall ◽  
Transitional Flow ◽  
Transfer Enhancement ◽  
Clearance Ratio ◽  
Near Wall

This paper investigated the flow performance around a near-wall cylinder and its effect on heat transfer enhancement in the laminar and early transitional flow region. The numerical model is resolved by finite volume method through FORTRAN code. The results show that the flow field becomes a transitional flow state when Re = 100 due to the insertion of a cylinder. In the transitional flow sate, the heat transfer enhancement is regional, mainly concentrating in the region of –2 ≤ x/D≤ 10, and the region increases with the increase of Re; There are three or four peaks in the distribution of instantaneous local Nusselt number. The first peak is caused by the acceleration of the fluid between the cylinder and the bottom wall. The other peaks are caused by the interaction between the cylinder wake and the bottom wall boundary layer. The vortical structure induced by the periodic instability of the fluid in the transitional flow is the main factor for explaining the local heat transfer enhancement of the cylinder downstream wall. Re has a direct impact on the vortical structure in the flow field. The greater Re, the greater the heat transfer enhancement of the cylinder downstream wall. Under the same blocking ratio of D/H, the greater Re, the smaller the optimal clearance ratio of C/D. The guidelines are suggested for the design on heat dissipation of electronic equipment.

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