An automatic and portable prosthetic cooling device with high cooling capacity based on phase change

2016 ◽  
Vol 104 ◽  
pp. 243-248 ◽  
Author(s):  
Yu Han ◽  
Fan Liu ◽  
Liang Zhao ◽  
Jiang Zhe
Keyword(s):  
Phase Change ◽  
Cooling Capacity ◽  
Cooling Device

Evaluation of Phase Change Materials for Personal Cooling Applications

2021 ◽  
pp. 0887302X2110530
Author(s):  
Lennart Teunissen ◽  
Emiel Janssen ◽  
Joost Schootstra ◽  
Linda Plaude ◽  
Kaspar Jansen
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Cooling Capacity ◽  
Packaging Material ◽  
Inorganic Salts ◽  
Cooling Power ◽  
Water Based ◽  
Similar Content ◽  
Personal Cooling ◽  
Power Segmentation

Eleven phase change materials (PCMs) for cooling humans in heat-stressed conditions were evaluated for their cooling characteristics. Effects of packaging material and segmentation were also investigated. Sample packs with a different type PCM (water- and oil-based PCMs, cooling gels, inorganic salts) or different packaging (aluminum, TPU, TPU + neoprene) were investigated on a hotplate. Cooling capacity, duration, and power were determined. Secondly, a PCM pack with hexagon compartments was compared to an unsegmented version with similar content. Cooling power decreased whereas cooling duration increased with increasing melting temperature. The water-based PCMs showed a >2x higher cooling power than other PCMs, but were relatively short-lived. The flexible gels and salts did not demonstrate a phase change plateau in cooling power, compromising their cooling potential. Using a TPU or aluminum packaging was indifferent. Adding neoprene considerably extended cooling duration, while decreasing power. Segmentation has practical benefits, but substantially lowered contact area and therefore cooling power.

Development of Silicon Based Heat Spreader for High Power Electronic Devices

2009 ◽  
Author(s):  
Qingjun Cai ◽  
Bing-chung Chen ◽  
Chailun Tsai ◽  
Yuan Zhao ◽  
Chung-lung Chen
Keyword(s):  
Mechanical Strength ◽  
Phase Change ◽  
Cooling Capacity ◽  
Working Fluid ◽  
Optimized Design ◽  
Heat Spreader ◽  
Vacuum Sealing ◽  
Mems Fabrication ◽  
Wick Structure ◽  
Silicon Based

This article presents the development of silicon based heat spreader devices, called hexcells. Several key technical aspects, including the hexcell MEMS fabrication process, mechanical strength studies, vacuum sealing technique, and phase change and mass transport visualization, have been developed and studied. The hexcell development prototypes are fabricated by MEMS photolithography and dry-etch processes, with eutectic bonding to form a sealed silicon chamber with openings for charging with the working fluid. Using Ansys as the modeling tool, we optimized the hexcell total mechanical strength by incorporating six interior support posts to reinforce the structure. In terms of the optimized design, experimental results on actual hexcell samples show that a well-bonded hexcell can withstand over 60psi without destructive failure. Vacuum sealing are divided into helium and vapor leakage tests. With metalized and solder-sealed sidewalls, both testing results confirm good vacuum sealing. The wick structure used in the present hexcell is silicon pillars with dimensions of 50μm in diameter and 250μm in height. The pillars are etched before the hexcell is bonded and formed. Experiments using the silicon wick structure demonstrate over 300W/cm2 cooling capacity and visualization shows the intensive phase change on the heating area.

Wickability and Transient Cooling Capacity of Binary Mixtures

2007 ◽  
Author(s):  
Mauricio A. Salinas ◽  
S. M. You ◽  
B. Elliott Short ◽  
Donald C. Price
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Metal Matrix ◽  
Solid Phase ◽  
High Heat ◽  
Cooling Capacity ◽  
Working Fluid ◽  
High Heat Flux ◽  
Testing Procedures ◽  
Change Material

Previously, aerospace and military, high heat-flux, electronics have been cooled with phase-change-modules composed of a metal-matrix saturated with a solid phase-change-material. This method requires the heat to be transferred from the source location, through the metal matrix, to the available phase-change-material. Empirical evaluations indicate that wick-based coldplates including non-metallic porous media, saturated with fluid may be much more effective. This wick-based method allows the capillary action of the wick to passively transport liquid from liquid-rich areas to the point of need; a much more efficient process. The optimization of a wick-based coldplate involves a careful balance between the wickability of the working fluid and its heat of vaporization (i.e. cooling capacity). The wickability and transient cooling capacity of both ethanol-water and methanol-water mixtures were empirically evaluated for the full mass fraction range. Testing procedures and results will be described in detail.

Passive Cooling With Phase Change Material Energy Storage

2013 ◽  
Author(s):  
Peter Omojaro ◽  
Cornelia Breitkopf ◽  
Simon Omojaro
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Energy Saving ◽  
Phase Change Material ◽  
Cooling System ◽  
Average Energy ◽  
Cooling Capacity ◽  
Sensible Heat ◽  
Cooling Temperature ◽  
Change Material

A passive induced cooling system using phase change material (PCM) energy storage is presented in this analysis for providing indoor cooling and energy saving. Also, the latent heat performance of the PCM is analyzed. The supplied cooling capacity was evaluated using an indoor cooling temperature performance while the PCM characteristic performance was achieved by relating the applications sensible heat ratio efficiency to the charging and discharging effectiveness of the PCM. This is carried out for an office building in a warm humid climate. Obtained result delivered 24.54 % of the required indoor cooling load for 24°C indoor cooling temperature. Moreover, delivered indoor cooling capacity increased at constant increasing mean indoor temperature and PCM melting temperatures. Application sensible heat ratio efficiency was 77.66 % and average energy saving of 37.77 % in total energy operation cost was obtained. A CO2 emission reduction of 0.071 tons can also be achieved by the system.

Cooling Capacity Figure of Merit for Phase Change Materials

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Patrick J. Shamberger
Keyword(s):  
Phase Change ◽  
Figure Of Merit ◽  
Phase Change Materials ◽  
Surrounding Medium ◽  
High Heat ◽  
Cooling Capacity ◽  
High Heat Flux ◽  
Two Phase ◽  
Fixed Temperature ◽  
Design And Optimization

In this paper, a figure of merit for the cooling capacity (FOMq) of phase change materials (PCMs) is defined from the analytical solution of the two-phase Neumann–Stefan problem of melting of a semi-infinite material with a fixed temperature boundary condition (BC). This figure of merit is a function of the thermophysical properties of a PCM and is proportional to the heat transfer across the interface with the surrounding medium in this general case. Thus, it has important implications for design and optimization of PCMs for high heat-flux thermal management applications. FOMq of example low melting point metals are presented which exceed those in common nonmetallic PCMs over the same temperature range by over an order of magnitude.

Cooling Capacity of Metal Phase Change Material for Thermal Management of Mobile Phone Subject to Long Time Communication

2013 ◽  
Author(s):  
Haoshan Ge ◽  
Jing Liu
Keyword(s):  
Phase Change ◽  
Mobile Phone ◽  
Phase Change Material ◽  
Thermal Management ◽  
Cooling Capacity ◽  
Metal Phase ◽  
Transfer Model ◽  
Transient Heating ◽  
Desktop Computer ◽  
Change Material

Smartphone is emerging as the most popular electronic media in the last few years. With many high performance chips integrated inside, such mobile electronic system is already capable of performing a series of sophisticated computing which can only be carried out by a desktop computer before. Meanwhile, the large amount of heat released from the high flux heat generation also caused evident thermal discomfort to the users. As a remedy, the recently proposed method of using low melting point metal to absorb the transitory heat from the device opens a promising approach for keeping smartphone cool. To push forward the development of this new thermal management method, the present study is dedicated to present a comprehensive analysis on the cooling capacity of the metal phase change material for the thermal management of mobile phone subject to various running states, especially those when extremely long conversation time up to a half hour or longer occurs. A three dimensional phase change heat transfer model was established to simulate several typical continuous or transient heating cases often encountered in reality. It can be found that, through an optimum design among the geometric sizes of the cooling modular, the chip structures as well as the utilized amount of the metal phase change material, the method is highly useful for cooling the mobile phone running even under an unconventionally long communication period. Further, improvement for a better and compact thermal management through material innovation was also suggested.

Layer-by-layer assembled phase change composite with paraffin for heat spreader with enhanced cooling capacity

2020 ◽  
Vol 204 ◽  
pp. 112287
Author(s):  
Chang Sung Heu ◽  
Su Ho Kim ◽  
Heung Soo Lee ◽  
Hyeon Woo Son ◽  
Jin Yong Mok ◽  
...  
Keyword(s):  
Phase Change ◽  
Cooling Capacity ◽  
Layer By Layer ◽  
Heat Spreader

Study on Performance Improvement of a Compressive Thermoelastic Cooling System Using Single Objective Optimization

2015 ◽  
Author(s):  
Suxin Qian ◽  
Abdullah Alabdulkarem ◽  
Jiazhen Ling ◽  
Yunho Hwang ◽  
Reinhard Radermacher
Keyword(s):  
Phase Change ◽  
Dynamic Model ◽  
Performance Improvement ◽  
Cooling System ◽  
Cooling Capacity ◽  
Heat Transfer Process ◽  
Martensitic Phase ◽  
Coefficient Of Performance ◽  
Cycle Frequency ◽  
Baseline Design

Thermoelastic cooling, also known as elastocaloric cooling, is one alternative cooling technology aiming to reduce the use of global warming potential refrigerants in vapor compression cycles. The cooling is based on the latent heat associated with the martensitic phase change induced by stress in shape memory alloys, driven by either compression or tension. A few past studies have explored and proposed the cycle options and system setup of a compressive thermoelastic cooling system using nitinol tubes as working material. The system coefficient of performance (COP) and cooling capacity were predicted by a dynamic model based on the physics of the integrated complicated heat transfer process and martensitic phase change. This study aims to start the performance improvement studies via optimization using the model. The objective function of the optimization problem is COP. Design variables include a few important operating parameters, such as flow rates and cycle frequency. The previously developed dynamic model is used to evaluate the system performance for this study. It is estimated that the COP enhancement can be as large as 51% from the baseline design candidate. Finally, an updated performance improvement potential is presented to guide future studies.

Assessment of a Phase Change Material (PCM) System for Moderating Temperature Rise of Solar Cells under Concentrated Sunlight

2010 ◽  
Vol 74 ◽  
pp. 205-210 ◽  
Author(s):  
Eric Casenove ◽  
Loic Pujol ◽  
Alexis Vossier ◽  
Arnaud Perona ◽  
Vincent Goetz ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Photovoltaic Cells ◽  
Temperature Profiles ◽  
Cooling Device ◽  
Cell Temperature ◽  
Graphite Phase ◽  
Cooling Systems ◽  
Change Material ◽  
Material Temperature

Experiments and simulations were carried out to assess a passive device for cooling photovoltaic cells under concentrated sunlight. The cooling device was made of a Graphite- Phase Change Material (PCM) composite inserted in an aluminum enclosure. The PCM considered in this work was selected among several commercially available materials. Experimental plots of material temperature versus time were recorded for various incident solar powers and compared to 3D-thermal simulation predictions. Theoretical cell temperature profiles obtained using the PCM-based device were compared to those obtained without PCM, that is, using bulk (PCM-free) aluminum heat sink. The interest of using PCM cooling systems in CPV applications was finally discussed.

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