On the thermal cooling of central processing unit of the PCs with vapor chamber ☆ Paisarn Naphon a, ⁎, Somchai Wongwises b , Songkran Wiriyasart a a Thermo-Fluids and Heat Transfer Enhancement Lab. (TFHT), Department of Mechanical Engineering, Faculty of Engineering, Srinakharinwirot University, 63 Rangsit-Nakhornnayok Rd., Ongkharak, Nakhorn-Nayok, 26120, Thailand b Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, 91 Suksawas 48, Bangmod, Bangkok 10140, Thailand abstract article info Available online 20 July 2012 Keywords: Vapor chamber Electronics cooling Central processing unit An experimental investigation on the thermal cooling of vapor chamber for cooling computer processing unit of the personal computer is performed. Two different configurations of the vapor chambers with de-ionized water as working fluid are tested under the real operating conditions of PCs. Parametric studies including dif- ferent aspect ratios, fill ratios, and operating conditions of PC on the CPU temperature are considered. It was found that the vapor chamber cooling technique has significant effect on the thermal cooling of CPU. Average CPU temperatures obtained from the vapor chamber cooling system are 4.1%, 6.89% lower than those from the conventional cooling system for no load and 90% operating loads, respectively. In additional, this cooling system requires 6.89%, 10.53% lower energy consumption for no load and 90% operating loads, respectively. The results of this study are of technological importance for the efficient design of cooling systems of the per- sonal computers or electronic devices to enhance cooling performance. © 2012 Elsevier Ltd. All rights reserved. 1. Introduction Higher performance processor will have larger heat generation. In order to ensure reliable operation, therefore, the PCs or electronics devices must be operated in the specific temperature ranges. For ef- fective cooling the heat must spread to a larger surface area and away from the processor, as there is usually restricted space available in the vicinity of the processor. The best known device for effective heat transfer with lowest thermal resistance is vapor chamber. The heat transfer characteristics of the vapor chamber have been widely studied by researchers. Hsieh et al. [1] analyzed the thermal resis- tance of vapor chamber heat sink with and without pillar for electron- ic cooling. Hu and Tang [2] investigated the flow and thermal characteristics of a microphase-change cooling system with a micro- groove evaporator. The results indicated that the liquid fill ratio has a significant influence on thermal resistance in the cooling system. Liu et al. [3] investigated startup of a novel two-phase cooling loop. Wang et al. [4] studied the micro‐capillary pumped loop system for a cooling high‐power device. Xie et al. [5] experimentally investigated a novel high-performance integrated heat pipe–heat sink for high-flux chip cooling. Hsieh et al. [6] examined the spreading ther- mal resistance of a flat vapor chamber. Vin and Astrain [7] studied the development of a thermoelectric refrigerator with two-phase thermosyphons. Chang et al. [8] experimentally investigated the ef- fects of the evaporation surfaces, fill ratios of working fluid and input heating powers on the thermal performance of the heat pipe cooling system with the thermal resistance model. Chen et al. [9] presented a numerical investigation of a plate-fin heat sink embed- ded with a vapor chamber, subject to the influence of concentrated heat sources. Zhang et al. [10] numerically and experimentally inves- tigated the flat two-phase thermosyphon. Ma et al. [11] developed an innovative one-side actuating piezoelectric micropump to drive liquid in a cooling system for a laptop. Vasiliev et al. [12] studied the loop heat pipe for cooling of high-power electronic components. Ming et al. [13] experimentally and numerically investigated the grooved vapor chamber. Khandekar et al. [14] investigated the multi- ple quasi-steady states in a closed loop pulsating heat pipe. Orian et al. [15] predicted the heat transfer coefficients for calculations of var- ious heat and mass transfer processes. Kang et al. [16] experimentally investigated the nanofluids on sintered heat pipe thermal perfor- mance. Tsai et al. [17] experimentally investigated the effects of heat source, fill ratio of working fluid, and evaporator surface struc- ture on the thermal performance of the vapor chamber. Wang et al. [18] considered the thermal performance of the vapor chamber for the high-power LEDs. Wong et al. [19] studied a novel vapor chamber with inner groove surface. Wang et al. [20] analyzed the thermal characteristics for board-level high‐performance package equipped with vapor chamber. Li et al. [21,22] investigated effects of the width, height and number of fins and of the Reynolds number on the thermal performance and surface temperature distributions of vapor chamber. Harmand et al. [23] presented a theoretical investiga- tion of a flat heat pipe for cooling electronic components. Wang et al. [24] analyzed the pressure-difference phenomenon between the condensing and boiling sections of a heat pipe. Reyes et al. [25] International Communications in Heat and Mass Transfer 39 (2012) 1165–1168 ☆ Communicated by W.J. Minkowycz. ⁎ Corresponding author. E-mail address: paisarnn@swu.ac.th (P. Naphon). 0735-1933/$ – see front matter © 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.icheatmasstransfer.2012.07.013 Contents lists available at SciVerse ScienceDirect International Communications in Heat and Mass Transfer journal homepage: www.elsevier.com/locate/ichmt