Convective Electronic Device Cooling Using Microencapsulated Phase Change Material Slurry in Planar Spiral Coil

2015 ◽  
Author(s):  
Houman B. Rokni ◽  
Ehsan M. Languri ◽  
Wayne Johnson
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Thermal Management ◽  
Carrying Capacity ◽  
Single Phase ◽  
Spiral Coil ◽  
Management Techniques ◽  
Spiral Coils ◽  
Change Material ◽  
Coil Heat

The current trend in miniaturization of electronic devises requires more effective thermal management techniques to remove the heat to ensure the maximum performance of the devise. Among all available thermal management techniques for electronic cooling, convective heat transfer cooling has gained attentions due to low cost and maturity in the market. The single-phase convective heat removal technique suffers from the low heat carrying capacity since there is no phase change occurs during the process. On the other hand, Microencapsulated phase change materials (MPCMs) are gaining attention due to their high heat carrying capacity. MPCMs are composed of phase change material (PCM) as the core material that is encapsulated with micrometer size shell materials. The PCM inside the capsules may undergo a phase change as the temperature varies around the melting and freezing temperature points of the PCM. This leads to a significant heat gain/release due to the phase change of the PCM. In this paper, we are performing a numerical modeling on the performance of MPCMs mixed with single-phase base fluid when pumped through planar spiral coils. From electronic thermal management point of view, it is ideal to have an enhanced coolant that maintain the operating temperature under an allowable level uniformly. The behavior of MPCM slurry when pumped through planar spiral coils reveals unique patterns due to the centrifugal forces. The available data on MPCM slurry through spiral coil heat exchangers show the new patterns of velocity and heat transfer curves that require further investigation and scientific explanations. The current paper studies the steady conditions of flows under laminar regimes at different boundary conditions. A CAD model of a planar coil heat exchanger is developed in SolidWorks. The model is meshed and discretized in order to apply the governing equations into the model. ANSYS Fluent package is used to solve the fluid flow and heat transfer equations inside the geometry. The velocity and temperature profiles along the coil are studied and discussed to quantify the roles of different forces in such flows. The ultimate goal of this study to evaluate the efficacy of utilizing such formulated microencapsulated PCM slurry at different mass concentrations on electronic thermal management considering the cost associated to the added pressure drop when using MPCM slurry.

Thermal Performance of Microencapsulated Phase Change Material Slurry in a Coil Heat Exchanger

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Min-Suk Kong ◽  
Kun Yu ◽  
Jorge L. Alvarado ◽  
Wilson Terrell
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Phase Change ◽  
Thermal Performance ◽  
Mass Fraction ◽  
Microencapsulated Phase Change Material ◽  
Coil Heat Exchanger ◽  
Change Material ◽  
Coil Heat

An experimental study has been carried out to investigate the convective heat transfer and pressure drop characteristics of microencapsulated phase change material (MPCM) slurry in a coil heat exchanger (CHX). The thermal and fluid properties of the MPCM slurries were determined using a differential scanning calorimeter (DSC) and a rotating drum viscometer, respectively. The overall heat transfer coefficient and pressure drop of slurries at 4.6% and 8.7% mass fractions were measured using an instrumented CHX. A friction factor correlation for MPCM slurry in the CHX has been developed in terms of Dean number and mass fraction of the MPCM. The effects of flow velocity and mass fraction of MPCM slurry on thermal performance have been analyzed by taking into account heat exchanger effectiveness and the performance efficiency coefficient (PEC). The experimental results showed that using MPCM slurry should improve the overall performance of a conventional CHX, even though the MPCM slurries are characterized by having high viscosity.

Numerical Simulation of a Microencapsulated Phase Change Material Slurry Flowing in a Helical Coil Heat Exchanger

2013 ◽  
Author(s):  
Ehsan M. Languri ◽  
Aly H. Shaaban ◽  
Minsuk Kong ◽  
Jorge L. Alvarado
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Phase Change ◽  
Phase Change Material ◽  
Heat Exchangers ◽  
Helical Coil ◽  
Microencapsulated Phase Change Material ◽  
Coil Heat Exchanger ◽  
Change Material ◽  
Coil Heat

Heat transfer analysis of microencapsulated phase change material (MCPM) slurry flowing through a helical coil heat exchanger was carried out numerically. MPCM slurry at different mass fractions with known thermal and physical properties was chosen as heat transfer fluid (HTF). MPCM slurries can carry significantly higher thermal load when the PCM undergoes phase change within a specified temperature range. However, little is known as to how MPCM behave in helical coil heat exchangers. Helical coil heat exchangers are being used widely in many industrial applications including air conditioning systems due to their compactness and high thermal effectiveness. Enhancing the heat transfer rate of coil heat exchanger by using MPCM slurry without altering the existing parameters of coil heat exchangers such as shell diameter should lead to energy savings due to reductions in HTF pumping energy demands at identical heat loads. The ultimate goal of this study is to show a significant enhancement in heat transfer when MPCM slurry is pumped through helical coil heat exchangers. Unlike traditional HTF used in helical coil heat exchangers, the proposed MPCM slurry could alter the flow structure and the internal convection by inducing and enhancing the formation of secondary flows, as a result of phase change in the microencapsulated phase change material. Specifically, a three dimensional numerical study was undertaken to understand the effects of the helical coil heat exchanger geometry and the HTF flow characteristics on heat transfer enhancement. Baseline numerical simulations were conducted using water as HTF in order to compare with MPCM slurry numerical results. The numerical model was solved based on the finite volume method. The temperature-dependent properties of MPCM slurry and boundary conditions were considered. The promising results of this numerical study demonstrate the importance of formulated HTF and the geometry of the heat exchanger on the heat transfer enhancement and energy savings.

An Experimental Study of Heat Transfer Characteristics of Microencapsulated Phase Change Material Slurry in a Coil Heat Exchanger

2013 ◽  
Author(s):  
Minsuk Kong ◽  
Jorge L. Alvarado ◽  
Ehsan M. Languri
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Phase Change ◽  
Phase Change Material ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Heat Transfer Characteristics ◽  
Coil Heat Exchanger ◽  
Change Material ◽  
Coil Heat

The use of microencapsulated phase change material (MPCM) slurry as an enhanced heat transfer fluid is considered to be very promising for saving energy in thermal energy systems. However, little is known how MPCM may exhibit enhanced heat transfer performance in coil heat exchanger. Coil heat exchangers are extensively used in industrial applications including heating, ventilating and air conditioning (HVAC) systems because of their superior heat transfer performance and compactness. In this study, the heat transfer characteristics of MPCM slurry in a coil heat exchanger have been investigated experimentally. Thermal properties of MPCM slurry were measured using a differential scanning calorimeter. Pressure drop, overall heat transfer coefficient and heat transfer effectiveness in a coil heat exchanger were determined by considering different flow rates. It was found that heat transfer characteristics were positively affected by the phase change process of the phase change material in MPCM, even though MPCM exhibit reduced turbulence and increased pressure drop. The overall heat transfer coefficient for MPCM slurry is in the range of 5,000 to 9,000 W/m2-K over a Dean number range from 1,600 to 4,000 (equivalent Reynolds number range of 6,000 to 15,000). The enhancement in heat transfer performance is about 17% when compared to that for water. In addition, durability tests of MPCM slurry were conducted to evaluate the MPCM’s ability to withstand continuous pumping conditions, which is critically important in the implementation of MPCM slurry in industrial applications.

scholarly journals Thermal management of photovoltaic panel with nano-enhanced phase change material at different inclinations

2021 ◽  
Author(s):  
UNNIKRISHNAN KARTHAMADATHIL SASIDHARAN ◽  
ROHINIKUMAR BANDARU
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Management ◽  
Thermal Energy ◽  
Liquid Fraction ◽  
Maximum Enhancement ◽  
Conduction Heat Transfer ◽  
Change Material

Abstract Photovoltaic (PV) panel, coupled with phase change material (PCM), has attracted broad attention for the panel's thermal management. Despite the higher energy storage capability of PCMs, the main disadvantage is their low thermal conductivity which is compensated to an extent with the nano-enhanced PCMs (NEPCMs). In this study, numerical simulations are carried out to compare the natural convection phenomena and thermal response of PV-NEPCM with simple PV-PCM for various tilt angles. CuO nanoparticles with a 4% volume concentration are selected for NEPCM. The thermal performance of PV-NEPCM at inclinations of 0°, 15°, 30°, and 45\(^\circ\) are compared with a simple PV-PCM system. The average temperature of PV, liquid fraction and thermal energy stored in PCM, the PV efficiency are compared for PV-PCM and PV-NEPCM systems. Results show that the loading of nanoparticles increases the conduction heat transfer inside PCM. It has also been shown that at lower inclinations, the use of NEPCM is more effective due to the dominance of conduction heat transfer. At higher tilt angles, natural convection plays a significant role in the heat transfer mechanism inside PCM. By using NEPCM, the maximum decrease in PV temperature of 1.11\(℃\) and maximum improvement in the liquid fraction (7.6%) are achieved when \({\theta }=0^\circ\) compared to simple PCM. Enhancement of thermal energy stored in PCM increases slightly upon adding nanoparticles, and the highest improvement is obtained for \({\theta }=0^\circ .\) Maximum enhancement of PV efficiency is found to be 1.6% for \({\theta }=0^\circ\) inclination on adding nanoparticles at a fraction of 4 vol.%. Keywords: PV, nano-enhanced PCM, nanoparticles, natural convection, liquid fraction.

Laminar Heat Transfer Behavior of a Phase Change Material Fluid in Microchannels With Staggered Pins

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Satyanarayana Kondle ◽  
Jorge L. Alvarado ◽  
Charles Marsh
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Phase Change ◽  
Phase Change Material ◽  
Single Phase ◽  
Internal Heat ◽  
Heat Removal ◽  
Heat Transfer Fluid ◽  
Change Material ◽  
Phase Fluid

Microchannels have been studied extensively for a variety of heat transfer applications including electronic cooling. Many configurations of microchannels have been studied and compared for their effectiveness in terms of heat removal. Recently, the use of staggered pins in microchannels has gained considerable traction, since they can promote internal flow fluctuations that enhance internal heat transfer. Furthermore, staggered pins in microchannels have shown higher heat removal characteristics because of the continuous breaking and formation of the heat transfer fluid boundary layer. However, they also exhibit higher pressure drop because the pins act as flow obstructions. This paper presents numerical results of two characteristic staggered 100-μm pins (square and circular) in microchannels. The heat transfer performance of a single phase fluid (SPF) in microchannels with staggered pins, and the corresponding pressure drop characteristics are presented. Furthermore, a phase change material (PCM, n-eicosane) fluid was also considered by implementing the effective specific heat capacity model approach to account for the corresponding phase change process of PCM fluid. Comparisons of the heat transfer characteristics of single phase fluid and PCM fluid are presented for two different pin geometries and three different Reynolds numbers. Circular pins were found to be more effective in terms of heat transfer by exhibiting higher Nusselt number. Microchannels with circular pins were also found to have lower pressure drop compared to the square-pin microchannels.

scholarly journals A numerical model and validation of phase change material integrated thermoelectric radiant cooling panel

2019 ◽  
Vol 111 ◽  
pp. 01001
Author(s):  
Hansol Lim ◽  
Hye-Jin Cho ◽  
Seong-Yong Cheon ◽  
Soo-Jin Lee ◽  
Jae-Weon Jeong
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Numerical Model ◽  
Surface Temperature ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Phase Change Material ◽  
Overall Heat Transfer Coefficient ◽  
Radiant Cooling ◽  
Change Material

A phase change material based radiant cooling panel with thermoelectric module (PCM-TERCP) is proposed in this study. It consists of two aluminium panels, and phase change materials (PCMs) sandwiched between the two panels. Thermoelectric modules (TEMs) are attached to one of the aluminium panels, and heat sinks are attached to the top side of TEMs. PCM-TERCP is a thermal energy storage concept equipment, in which TEMs freeze the PCM during the night whose melting temperature is 16○C. Therefore, the radiant cooling panel can maintain a surface temperature of 16◦C without the operation of TEM during the day. Furthermore, it is necessary to design the PCM-TERCP in a way that it can maintain the panel surface temperature during the targeted operating time. Therefore, the numerical model was developed using finite difference method to evaluate the thermal behaviour of PCM-TERCP. Experiments were also conducted to validate the performance of the developed model. Using the developed model, the possible operation time was investigated to determine the overall heat transfer coefficient required between radiant cooling panel and TEM. Consequently, the results showed that a overall heat transfer coefficient of 394 W/m2K is required to maintain the surface temperature between 16○C to 18○C for a 3 hours operation.

Sign in / Sign up

Export Citation Format

Share Document