Transient Thermal Management of a Handset Using Phase Change Material (PCM)

2002 ◽  
Vol 124 (4) ◽  
pp. 419-426 ◽  
Author(s):  
Marc Hodes ◽  
Randy D. Weinstein ◽  
Stephen J. Pence ◽  
Jason M. Piccini ◽  
Lou Manzione ◽  
...  
Keyword(s):  
Steady State ◽  
Phase Change ◽  
Thermal Management ◽  
Phase Change Materials ◽  
Maximum Temperature ◽  
Ir Camera ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Time Required ◽  
Transient Thermal

The power density of portable electronic devices continues to increase because packaging advances reduce their size even as features are added and enhanced. Designing thermal management systems to accommodate steady-state conditions as opposed to fixed duty cycles can substantially increase cost, size, and weight. The feasibility of transient thermal management of handsets using phase change materials (PCMs) was experimentally investigated using an ABS handset mock-up. At selected intervals of time, the nonuniform case temperature of the handset was measured using an infrared (IR) camera, while thermocouples measured the temperatures of the PCM and simulated power amplifier (heater). Transient and steady-state heat transfer rates by natural convective and radiation from the handset to the environment were numerically computed from the temperature data in the thermal images. The effects of PCM material, power supplied to the handset, and handset orientation on the time required for the handset case to reach a given (maximum) temperature and “recovery” time were examined.

An Investigation Into the Penetration of Phase Change Material in Carbon Foam for Transient Thermal Management

2009 ◽  
Author(s):  
Omar Sanusi ◽  
Randy D. Weinstein ◽  
Amy S. Fleischer
Keyword(s):  
Phase Change ◽  
Thermal Management ◽  
Phase Change Materials ◽  
High Capacity ◽  
Carbon Foam ◽  
Storage Device ◽  
Foam Structure ◽  
Transient Thermal ◽  
Change Material ◽  
Initial Research

Phase Change Materials (PCMs) are used for thermal management and are ideal for cyclic operations due to their high capacity to store heat. Most PCMs do not exhibit sufficient conductivity to be effective at larger sizes. Enhancing conductivity can be done in a number of ways including carbon foam. It is not widely known how well PCMs penetrate inside the carbon foam structure. Initial research suggests that the carbon foam-PCM matrix acts more as a conductor than a thermal storage device. Through the use microscopy, we will examine how the well the PCM penetrates into the carbon foam. We will also use experimental data comparing carbon foam enhanced modules to pure PCM modules. A volume displacement test will also be used to determine the quantity of PCM that enters into the carbon foam structure. This knowledge will allow better design of enhanced PCM modules and will determine if carbon foam is indeed a viable conduction enhancer for PCM thermal management.

Comparative Study between DSC and Two Complementary Performance Evaluation Methods for PCM-Treated Textiles

2014 ◽  
Vol 941-944 ◽  
pp. 1350-1354 ◽  
Author(s):  
Farzad Mohaddes ◽  
Saniyat Islam ◽  
Robert A. Shanks ◽  
Li Jing Wang ◽  
Rajiv Padhye
Keyword(s):  
Image Analysis ◽  
Performance Evaluation ◽  
Steady State ◽  
Phase Change Materials ◽  
Digital Data ◽  
Data Logger ◽  
Ir Camera ◽  
Time Required ◽  
Temperature Time ◽  
Ir Light

Evaluation of thermoregulation performance of textiles incorporated with phase change materials (PCMs) has long been dependent on differential scanning calorymetry (DSC). However, some parameters like the time required for reaching the steady state and the effect of multiple layering cannot be characterized by calorimetric methods. In this paper, Newton cooling law was fitted to the temperature–time graphs of PCM-treated and untreated fabrics obtained by a digital data-logger. By definition, lower values of α in Newton cooling law associates with higher thermoregulation effect. The effect of using different layers as well as thermoregulation efficiency of PCM-treated fabrics were investigated by this method. Thermal imagining was another method employed to calculate thermoregulation percentage (TP) of the fabrics exposed to an infrared, IR, light source. The temperature–time graphs obtained by an IR camera were populated, and the corresponding TP percentages were calculated by image analysis. At the end, the results obtained by two suggested methods were qualitatively compared with DSC.

Thermal Analysis of Phase Change Materials With Embedded Graphite Nanofibers for Thermal Management of Electronics

2006 ◽  
Author(s):  
Thomas C. Kopec ◽  
Randy D. Weinstein ◽  
Amy S. Fleischer ◽  
Elizabeth D'Addio ◽  
Carol A. Bessel
Keyword(s):  
Phase Change ◽  
Thermal Management ◽  
Phase Change Materials ◽  
Thermal Response ◽  
Weight Percent ◽  
Fiber Loading ◽  
Graphite Nanofibers ◽  
Thermal Management Of Electronics ◽  
Cubic System ◽  
Transient Thermal

Phase change materials (PCMs) exhibit excellent thermal storage capacity due to their high latent heat of transformation and have been successfully utilized in small volumes for transient thermal management of electronics. However, their low thermal diffusivity makes it difficult to utilize large volumes of PCMs for transient thermal management of high power density systems. To improve the thermal performance of a paraffin PCM, high thermal conductivity graphite nanofibers are embedded into the paraffin PCM. The thermal effects of graphite fiber loading levels, measured in weight percent, are examined for a 131 cm3 volume cubic system with power loads of 3 and 7 W. It is found that the thermal response of the system improves with increased fiber loading levels.

An Investigation of the Effect of interrupted fin arrangements on the Thermal Performance of a Heat Sink under a Free Convection Condition

2019 ◽  
Vol 7 (1) ◽  
pp. 43-53
Author(s):  
Abbas Jassem Jubear ◽  
Ali Hameed Abd
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Numerical Study ◽  
Ansys Fluent ◽  
Fluent Software ◽  
Steady State Heat ◽  
Steady State Heat Transfer

The heat sink with vertically rectangular interrupted fins was investigated numerically in a natural convection field, with steady-state heat transfer. A numerical study has been conducted using ANSYS Fluent software (R16.1) in order to develop a 3-D numerical model.  The dimensions of the fins are (305 mm length, 100 mm width, 17 mm height, and 9.5 mm space between fins. The number of fins used on the surface is eight. In this study, the heat input was used as follows: 20, 40, 60, 80, 100, and 120 watts. This study focused on interrupted rectangular fins with a different arrangement and angle of the fins. Results show that the addition of interruption in fins in various arrangements will improve the thermal performance of the heat sink, and through the results, a better interruption rate as an equation can be obtained.

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