Capillary Pumped Loop Heat Spreader for Electronics Cooling

Author(s):  
Jaewon Chung ◽  
Costas P. Grigoropoulos ◽  
Ralph Greif

Abstract As cooling requirements for electronic devices, e.g. computer processor units, power modules, etc. increase beyond the capabilities of air-cooling, interest has moved to several alternatives such as thermoelectric coolers, impinging jets and heat exchangers with phase change. Included among these, the capillary pumped loop is a very competitive cooling device, because of its performance reliability, no power requirements and low manufacturing cost. In this paper, a heat spreader employing capillary pumped loop principles was made of aluminum and copper and tested. The copper CPL heat spreader with heat sinks and fans on the condenser (86mm thick, 60mm wide, 181mm long) has demonstrated a cooling capacity of 640W at atmospheric pressure in the vertical orientation and maintains a difference between TIHE (temperature of the interface between heater and evaporator) and TAMB (ambient temperature) lower than 100°C.

Author(s):  
Qingjun Cai ◽  
Bing-Chung Chen ◽  
Chailun Tsai ◽  
Chung-lung Chen

A silicon heat spreader, called hexcell, is presented to develop thin, strong, interconnected, and scalable heat transfer devices for high power electronics cooling. Several key technical aspects, reflected characteristics of fabrication, thermomechanical, hermetic sealing, and heat transfer on wick structures, have been performed to underlie the system integration. The hexcell prototypes are developed through microelectromechanical system photolithography and dry-etch processes, associated with eutectic bonding to form a sealed silicon chamber. Hexcells are structurally optimized to minimize the stress, expanding the maximum operating pressure and temperature ranges. As a result, the developed hexcells can survive 0.32 MPa pressure difference and are able to sustain an operating temperature over 135°C. Experimental results of both helium and vapor leakage tests indicate that eutectic bonding with limited bonding surface area may not provide hermetic sealing. Vacuum sealing is achieved by introducing epoxy to fill the leak pine-holes on the bonding interface. The developed hexcell wick exhibits good heat and mass transport performance, reaching a maximum 300 W/cm2 cooling capacity with 35°C superheat as demonstrated with a prototype of a 2×2 mm2 heating area.


2020 ◽  
Vol 12 (4) ◽  
pp. 1564
Author(s):  
Kashif Irshad ◽  
Abdulmohsen Almalawi ◽  
Asif Irshad Khan ◽  
Md Mottahir Alam ◽  
Md. Hasan Zahir ◽  
...  

This study investigates the performance of the thermoelectric air conditioning (TE-AC) system smartly controlled by the Internet of Things (IoT)-based configuration for real tropical climatic application. Air cooling management was done through thermoelectric coolers, and an Arduino microcontroller with various sensors such as a temperature sensor, simple RF modules, and actuators was used to control the indoor climatic conditions based on outdoor conditions. The result shows that when the input power supply to the IoT-based TE-AC system is increased, the cooling capacity of the framework is also enhanced. Significant power and carbon emission reduction was observed for the IoT-based TE-AC system as compared to the TE-AC system without IoT. The IoT-incorporated system also ensures better microclimatic temperature control. Additionally, the system cooling capacity improves by 14.0%, and the coefficient of performance is increased by 46.3%. Thus, this study provides a smart solution to the two major energy harvesting issues of traditional air conditioners—an increase in energy efficiency by employing a TE-AC system and a further improvement in efficiency by using an IoT-based thermal management system.


Author(s):  
M. C. Wu ◽  
C. H. Peng ◽  
C. Y. Lee ◽  
C. J. Fang ◽  
Y. H. Hung

The demand for high execution speed and memory capacity for modern computers results in an increasing circuit density per unit chip and high power dissipation per unit volume. Consequently, traditional air cooling technology such as air-cooled heat sink is reaching the limits for electronic applications. Thermoelectric coolers are regarded as potential solutions for enhancing the performance of air-cooled heat sinks. In the present study, a semi-empirical method for exploring the thermal performance of a heat sink integrated with or without TEC has been successfully established. A concept of design of experiments (DOE) is applied, and a statistical method for sensitivity analysis of the influencing parameters is performed to determine the key factors that are critical to the design. By the statistical sensitivity analysis of ANOVA F-test for the temperature reduction (ΔTC−B) and COP of the TEC, the factor contributions of QP, Rext and I are 31.66%, 33.73%, 34.61% as well as 14.9%, 0%, 85.1%, respectively. By employing the gradient-based numerical optimization technique, a series of constrained optimal designs have been performed. Under the given constraints of COP≧2, the optimal value of ΔTC−B (3.3°C) is obtained with the corresponding Qp (31.99W) and Qte (16W). Comparisons between the results by the present optimal design and those obtained by the semi-empirical results have been made with a satisfactory agreement. The present optimal design shows that a heat sink integrated with TEC can extend the upper limits of thermal management for traditional air-cooled heat sinks.


Author(s):  
M. Zugic ◽  
J. R. Culham ◽  
P. Teertstra ◽  
Y. Muzychka ◽  
K. Horne ◽  
...  

Compact, liquid cooled heat sinks are used in applications where high heat fluxes and boundary resistance preclude the use of more traditional air cooling techniques. Four different liquid cooled heat sink designs, whose core geometry is formed by overlapped ribbed plates, are examined. The objective of this analysis is to develop models that can be used as design tools for the prediction of overall heat transfer and pressure drop of heat sinks. Models are validated for Reynolds numbers between 300 and 5000 using experimental tests. The agreement between the experiments and the models ranges from 2.35% to 15.3% RMS.


Author(s):  
Shankar Krishnan ◽  
Domhnaill Hernon ◽  
Marc Hodes ◽  
John Mullins ◽  
Alan M. Lyons
Keyword(s):  

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1773
Author(s):  
Yu Wang ◽  
Lin Ruan

A combined circulation system of spray evaporative cooling and air cooling (CCSSECAC) is a way to enhance the cooling performance of an air-cooled electric machine while maintaining its existing structure. Based on a traditional air-cooled machine, when the discrete evaporative cooling medium particles are scattered into the airflow, they will reach the heat source with the air circulation. The cooling capacity of the cooling system is enhanced simultaneously through the phase transition and convection heat transfer. Ultrasonic atomization is a simple way to produce tiny droplets and a good way to improve the performance of CCSSECAC. To verify the effectiveness of such a system, a principle test model was built and a multi-operational condition experiment was carried out as an exploratory study. The experimental results showed that the new cooling system was feasible for horizontal machines, and the stator coil temperature was significantly reduced compared with the air-cooled mode.


Author(s):  
Tunc Icoz ◽  
Mehmet Arik ◽  
John T. Dardis

Thermal management of electronics is a critical part of maintaining high efficiency and reliability. Adequate cooling must be balanced with weight and volumetric requirements, especially for passive air-cooling solutions in electronics applications where space and weight are at a premium. It should be noted that there are systems where thermal solution takes more than 95% of the total weight of the system. Therefore, it is necessary to investigate and utilize advanced materials to design low weight and compact systems. Many of the advanced materials have anisotropic thermal properties and their performances depend strongly on taking advantage of superior properties in the desired directions. Therefore, control of thermal conductivity plays an important role in utilization of such materials for cooling applications. Because of the complexity introduced by anisotropic properties, thermal performances of advanced materials are yet to be fully understood. Present study is an experimental and computational study on characterization of thermal performances of advanced materials for heat sink applications. Numerical simulations and experiments are performed to characterize thermal performances of four different materials. An estimated weight savings in excess of 75% with lightweight materials are observed compared to the traditionally used heat sinks.


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