scholarly journals Transient and cyclic effects on a PCM-cooled mobile device

2015 ◽  
Vol 19 (5) ◽  
pp. 1723-1731 ◽  
Author(s):  
C.P. Tso ◽  
F.L. Tan ◽  
J. Jony
Keyword(s):  
Heat Pipe ◽  
Heat Dissipation ◽  
Heat Storage ◽  
Power Level ◽  
Internal Heat ◽  
Transient Temperature ◽  
Storage Unit ◽  
Transient Temperature Distribution ◽  
The Individual ◽  
Change Material

A mock handset with heat storage unit (HSU) has been designed, fabricated, and experimented under various conditions to examine the effect of external heat sink on the handset?s transient temperature distribution, performance of the individual HSU under different power level and orientation, as well as under the more realistic cyclic heating. The cooling of the handset is through using a phase change material (PCM), n-eicosane, stored in the external HSU connected to the handset through a miniature heat pipe. The heat pipe channels the internal heat dissipation to the HSU where it is absorbed by the PCM. Results show that the temperature is significantly lowered with the PCM-based HSU.

Post Fire Transient Temperature Distribution in Drum Type Packages in the Absence of Heat Generation

2003 ◽  
Author(s):  
Allen C. Smith
Keyword(s):  
Thermal Conductivity ◽  
Temperature Distribution ◽  
Heat Generation ◽  
Heat Storage ◽  
Internal Heat ◽  
Thermal Response ◽  
Transient Temperature ◽  
Test Cases ◽  
Transient Temperature Distribution ◽  
Parametric Studies

This study investigates the temperature distribution in an idealized cylindrical package subjected to the HAC Fire transient, with no internal heat generation. Cases for overpack materials with thermal conductivity spanning two orders of magnitude are considered. The results show that the peak internal temperature is determined by the thermal conductivity of the overpack material, for this case. The thermal wave effect, where the interior temperature continues to rise after the end of the fire exposure, is present in all three of the test cases. For contents with no heat generation, the most desirable overpack materials would have low thermal conductivity and low heat storage capability. The study complements the parametric studies of effects of thermal properties on thermal response of packages which were previously reported.

scholarly journals The Heat-Dissipation and Dehumidification System of the Hybrid Multi-Layer Gravity Heat Pipe Applied to Granary

2019 ◽  
Vol 13 (8) ◽  
pp. 76
Author(s):  
Guoyong Su ◽  
Yu Wu ◽  
Wei Gao
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Dissipation ◽  
Internal Heat ◽  
Internal Temperature ◽  
Transfer Mode ◽  
Working Principle ◽  
Booster Fan ◽  
Working Efficiency ◽  
Dissipation System

Based on the basic working principle and heat transfer characteristics of gravity heat pipe in combination with the grain stack particle's stacking characteristics, this study changes the structure of traditional heat pipe to change the heat transfer mode between the grain stack and the gravity heat pipe so as to improve the grain's heat-dissipation rate and heat-dissipation efficiency. Generally, this system can satisfy the internal heat dissipation requirements of grain stack only under the action of a non-power fan driven by the air in the atmosphere and the temperature difference between inside and outside of the fan. When the internal temperature sensor of the grain stack detects that the internal temperature of the grain stack is high only under the action of the non-power fan, the pipeline booster fan will be started. At the same time, when the gas exchange occurs between the internal gas in grain stack and the external air, the dehumidification and drying of the grain stack can be realized through the gas drying device of the product. Through theory and simulation, this paper conducts a comparative analysis on the variation law of grain stack's temperatures under the action of gravity heat pipe and no gravity heat pipe so as to explore the heat-dissipation system's working efficiency of the new structure gravity heat pipe. The gravity heat pipe and the non-power fan in the system are all green products, which makes this design product have better heat-dissipation effect and less energy consumption.

scholarly journals Design, Developing and Construction of an Educational Solar Water Heating System with Phase Change

2015 ◽  
Vol 10 (1) ◽  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Solar Collector ◽  
Heat Storage ◽  
Heating System ◽  
Storage Unit ◽  
Solar Water Heating ◽  
Solar Water ◽  
Solar Water Heating System ◽  
Change Material

An educational solar water heater with phase change material (PCM) was designed, developed, and constructed for instructional and demonstrative purposes. This interactive solar water heating system experimental apparatus is capable of demonstrating thermal energy storage and heat transfer concepts and principles. The system consists of two simultaneously functioning heat absorbing units. The first is a flat plate solar collector and the other is a heat storage unit consisting of phase change material (paraffin wax). The heat storage unit utilizes small aluminium cylinders (heat exchangers) filled with paraffin wax as the heat storage medium. Water pump is used to circulate the water between the solar collector and the storage unit where the PCM is located. Results indicate that the PCM stored energy, as latent heat, that was absorbed by the solar collector and released to heat the water in the storage tank when half of the hot water was replaced with cold water. Moreover, tests indicated that latent heat storage is more effective than sensible.

The Transient Temperature Distribution in One-Dimensional Heat-Conduction Problems With Nonlinear Boundary Conditions

1969 ◽  
Vol 91 (1) ◽  
pp. 77-82 ◽  
Author(s):  
W. Z˙yszkowski
Keyword(s):  
Boundary Condition ◽  
Temperature Distribution ◽  
Nonlinear Boundary ◽  
Internal Heat ◽  
Nonlinear Boundary Conditions ◽  
Transient Temperature ◽  
One Dimensional ◽  
Parabolic Profile ◽  
Transient Temperature Distribution ◽  
Approximate Analytical Solutions

The transient, one-dimensional temperature distribution is determined for bodies with internal heat generation and nonlinear boundary condition in the form: k·e·gradθ+ε(θn−T0n)+ε1(θ−T0)=0 Approximate analytical solutions are derived with the aid of Biot’s variational method. The additional boundary condition introduced by Lardner is modified, and this modification makes it possible to solve the problem. The solution has been obtained assuming a parabolic profile of temperature distribution. Formulas are given for plates, cylinders, and spheres. Some results are illustrated with the graphs, and compared with the exact solution for the case of convective heat transfer.

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