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A. Akbarzadeh

Bio: A. Akbarzadeh is an academic researcher from Melbourne Institute of Technology. The author has contributed to research in topics: Thermal resistance & Micro-loop heat pipe. The author has an hindex of 2, co-authored 3 publications receiving 129 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a copper miniature loop heat pipe (mLHP) with a flat disk shaped evaporator, 30mm in diameter and 10-mm thick, was designed for thermal control of computer microprocessors.
Abstract: This paper presents an experimental investigation on a copper miniature loop heat pipe (mLHP) with a flat disk shaped evaporator, 30mm in diameter and 10-mm thick, designed for thermal control of computer microprocessors. Tests were conducted with water as the heat transfer fluid. The device was capable of transferring a heat load of 70W through a distance up to 150mm using 2-mm diameter transport lines. For a range of power applied to the evaporator, the system demonstrated very reliable startup and was able to achieve steady state without any symptoms of wick dry-out. Unlike cylindrical evaporators, flat evaporators are easy to attach to the heat source without need of any cylinder-to-plane reducer material at the interface and thus offer very low thermal resistance to the heat acquisition process. In the horizontal configuration, under air cooling, the minimum value for the mLHP thermal resistance is 0.17degC/W with the corresponding evaporator thermal resistance of 0.06degC/W. It is concluded from the outcomes of the current study that a mLHP with flat evaporator geometry can be effectively used for the thermal control of electronic equipment including notebooks with limited space and high heat flux chipsets. The results also confirm the superior heat transfer characteristics of the copper-water configuration in mLHPs

99 citations

Journal ArticleDOI
TL;DR: In this paper, two different designs of miniature loop heat pipes (mLHPs) for thermal control of compact electronic devices including notebooks were investigated. But they were not used for laptop thermal management.
Abstract: Thermal management of laptops is an increasingly challenging task because of the high-heat flux associated with the microprocessors and the limited space available for the thermal control system inside the cabinet. In this paper, results are discussed from an investigation of two different designs of miniature loop heat pipes (mLHPs) for thermal control of compact electronic devices including notebooks. Two prototypes of mLHP, one with a disk-shaped evaporator, 30 mm diameter and 10 mm thick, and the other with a rectangular-shaped evaporator, 47 × 37 mm2 plan area and 5 mm thick, were designed to handle heat fluxes up to 50 W/cm2. In the disk-shaped evaporator, the compensation chamber was incorporated into the overall thickness of the evaporator, whereas for the rectangular-shaped evaporator a new design approach was used in which the compensation chamber was positioned on the sides of the wick structure such that it was coplanar with the evaporator section. The new design approach helped to decrease the thickness of the rectangular evaporator by 50% and therefore improved the ability to integrate miniature loop heat pipe technology into compact electronics enclosures. All of the thermal tests on mLHP prototypes were conducted in horizontal configurations. Total thermal resistance of the designed mLHPs was between 1 and 5° C/W. A comparative study of the mLHPs with conventional heat pipe and microchannel-based active liquid cooling systems has shown the superior heat transfer capability of the passively operating loop scheme for high-heat flux applications, and helped to classify mLHPs as candidates for laptop thermal management.

47 citations

01 Jan 2006
TL;DR: In this article, a miniature loop heat pipe (mLHP) with the flat disk shaped evaporator, 30 mm in diameter and 10 mm thick, was developed for cooling microprocessors with local hot spots and non-uniform heating patterns.
Abstract: In the new generation microprocessors, it is observed that the power density over the active surface can vary from uniform to non uniform modes depending on the clock speed and the processing load on the chipset. The latter mode of operation can result in hot spots on the microprocessors that can result in the increase of the local temperature above the permissible limit and ultimately in the failure of the electronic device. In order to propose a solution for this problem a miniature loop heat pipe (mLHP) with the flat disk shaped evaporator, 30 mm in diameter and 10 mm thick, was developed. The proposed mLHP was tested under uniformly as well as non-uniformly heating mode. In the uniform heating, the entire active area of the evaporator was heated while in the non-uniform mode only 14% of the evaporator active area was heated locally. The thermal performance of the mLHP under these heating modes was compared on the basis of the evaporator wall temperature and thermal resistance between different loop components. The results of the experiment help to classify mLHP as the viable thermal solution for the cooling of microprocessors with local hot spots and non-uniform heating patterns

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Journal ArticleDOI
TL;DR: In this article, the state-of-the-art of multi-level thermal management techniques for both air- and liquid-cooled data centers is reviewed. But the main focus is on the sources of inefficiencies and the improvement methods with their configuration features and performances at each level.

272 citations

Journal ArticleDOI
TL;DR: A review of small heat pipes, including their design, analysis, and fabrication, is presented in this article, where the authors also discuss the potential of nano-wicks, such as carbon nanotubes (CNTs), to represent the future of heat pipes.

205 citations

Journal ArticleDOI
TL;DR: In this paper, the authors compared the heat transfer characteristics of several cooling technologies with potential application in the server electronics industry and concluded that some form of liquid cooling is necessary in high performance computing applications.

164 citations

Journal ArticleDOI
TL;DR: In this paper, an analytical review of development, results of tests and simulation of loop heat pipes with disk-shaped, rectangular and flat-oval evaporators is presented, which may be arbitrarily separated into evaporators with opposite replenishment (EORs) and evaporators of longitudinal replenishment.

150 citations

Journal ArticleDOI
TL;DR: In this article, a copper-water compact loop heat pipe (LHP) with a unique flat, square evaporator with dimension of 30mm (L )×30mm (W )×15mm (H ) and a connecting tube having an inner diameter of 5mm.

123 citations