A thermal design approach for natural air cooled electronic equipment casings
01 Oct 2013-pp 67-70
TL;DR: In this article, an attempt has been made to study the effects of the outlet vent area and power dissipation unit location on the natural air-cooled electronic equipment casings.
Abstract: In recent years, the increasing demand of compactness and high-speed performance of electronic equipment had led to an increasing trend of power dissipation density. Therefore, suitable cooling techniques to the thermal designing of electronic equipment need to be developed. Several research reports on electronic equipment cooling are available in the literature sources [1-5]. In these studies it can be observed that air-cooling is getting one of the important cooling techniques, since most of the electronic equipment are cooled by air convection. Although fan cooling is most widely used in the air cooling techniques, the noise generated by the fan is publicly criticized. As a result, cooling on the basis of natural convection is one of the attractive approaches. However, only limited data on natural convection, which can be used in the practical design of electronic equipment, are available. Noronha [6] studied the effect of the component locations in cabinets to achieve maximum natural cooling efficiency. Guglielmini et al [7] have reported on the natural air cooling of electronic cards in ventilated enclosures. Ishizuka et al. [8] proposed an approach using a simplified set of equations which represent the cooling capability through a natural air-cooled electronic equipment casings. However, detailed discussions on derivation of the set of equations were not made in that paper. Therefore, in the present work, an attempt has been made to study the effects of the outlet vent area and power dissipation unit location on the natural air-cooled electronic equipment casings.
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TL;DR: In this paper, the authors carried out thermal design and evaluated the cooling performance of power electronic devices (PEDs) containing electronic equipment, and the experimental results rove the effectiveness of numerical simulation and electronic equipment cooling scheme.
Abstract: Received: 5 January 2021 Accepted: 11 March 2021 In electronic equipment, thermal failure and thermal degradation are two increasingly prominent problems of the devices, with the deepening integration and growing power density. Currently, there are relatively few reports on the heat transfer mechanism, heat source analysis, and numerical simulation of electronic equipment containing power electronic devices (PEDs). Therefore, this paper carries out thermal design and evaluates the cooling performance of PED-containing electronic equipment. Firstly, the basic flow was given for the thermal design of PED-containing electronic equipment; the heat transfer mode of PEDs and the equipment were detailed, so was the principle of thermal design; the cooling principles were introduced for ventilation cooling, heat pipe cooling, and closed loop cooling. Then, numerical simulation was carried out on the solid and liquid state heat transfer of PEDs and the equipment under different cooling modes. Based on an engineering example, the cooling scheme was finalized through heat source analysis on the proposed electronic equipment. The experimental results rove the effectiveness of numerical simulation and electronic equipment cooling scheme. The results provide a reference for the cooling scheme design for other fields of thermal design.
3Â citations
Cites background from "A thermal design approach for natur..."
...The thermal design of PED-containing electronic equipment requires theoretical knowledge of multiple disciplines, namely, electronics, heat transfer, mechanics, and fluid mechanics, and calls for overall consideration of the unique features in the cooling of closed equipment, which is characterized by heat concentration, a small radiating surface, and a high heat flux [7]....
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22 Dec 2011
TL;DR: In this article, the authors studied the effect of the distance between the outlet vent location and the heat source on the cooling capability of natural-air-cooled electronic equipment casings.
Abstract: As the power dissipation density of electronic equipment has continued to increase, it has become necessary to consider the cooling design of electronic equipment in order to develop suitable cooling techniques. Almost all electronic equipment is cooled by air convection. Of the various cooling systems available, natural air cooling is often used for applications for which high reliability is essential, such as telecommunications. The main advantage of natural convection is that no fan or blower is required, because air movement is generated by density differences in the presence of gravity. The optimum thermal design of electronic devices cooled by natural convection depends on an accurate choice of geometrical configuration and the best distribution of heat sources to promote the flow rate that minimizes temperature rises inside the casings. Although the literature covers natural convection heat transfer in simple geometries, few experiments relate to enclosures such as those used in electronic equipment, in which heat transfer and fluid flow are generally complicated and three dimensional, making experimental modeling necessary. Guglielmini et al. (1988) reported on the natural air cooling of electronic boards in ventilated enclosures. Misale (1993) reported the influence of vent geometry on the natural air cooling of vertical circuit boards packed within a ventilated enclosure. Lin and Armfield (2001) studied natural convection cooling of rectangular and cylindrical containers. Ishizuka et al. (1986) and Ishizuka (1998) presented a simplified set of equations derived from data on natural air cooling of electronic equipment casings and showed its validity. However, there is insufficient information regading thermal design of practical electronic equipment. For example, the simplified set of equations was based on a ventilation model like a chimney with a heater at the base and an outlet vent on the top, yet in practical electronic equipment, the outlet vent is located at the upper part of the side walls, and the duct is not circular. Therefore, here, we studied the effect of the distance between the outlet vent location and the heat source on the cooling capability of natural-air-cooled electronic equipment casings.
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132Â citations
TL;DR: In this article, a measuring system for determining the resistance values for perforated plates in an air free convection path was designed, and the measuring system and resistance values were obtained by using the system.
Abstract: With the recent rapid increase in close packaging density, and higher power for electronic equipment, the cooling design involved in casings which enclose them has become more important. For the electronic equipment cooling design, data on flow path resistance in the casing are needed. The most significant factors in the flow resistance are considered to be vent perforations. However, all the resistance data for perforated plates were obtained for forced convective flows (higher Reynolds numbers), as reported by Collar (1939), Macphail (1939), and Taylor (1949). Smith and Van Winkle (1957) studied discharge coefficients through perforated plates at a wide Reynolds number range of 2,000 to 20,000, and Kolodzie and Van Winkle (1958) also made a study at a 400 to 3,000 Reynolds number range. Their work was limited to a lower porosity coefficient range of 0.023 to 0.158. However, resistance data in air free convection paths have not been reported. Therefore, the measuring system for determining the resistance values for perforated plates in an air free convection path was designed. This note describes the measuring system and resistance values for perforated plates obtained by using the system.
12Â citations
TL;DR: In this article, a simple formula for thermal designing of natural-air-cooled electronic equipment casings with standard arrangement of circuit boards and power supplies was presented, since it represents an air cooling system in its simplified form with due regard to such factors as the stack effect, air flow resistance, natural convective transfer and so on.
Abstract: This paper presents a simple formula for thermal designing of natural-air-cooled electronic equipment casings with standard arrangement of circuit boards and power supplies The formula meets the requirements as a practical formula, since it represents an air-cooling system in its simplified form with due regard to such factors as the stack effect, air flow resistance, natural convective transfer and so on The formula was applied to predict the temperature rise in two practically used electronic equipment cabinets with standard arrangements and a modeling case The predicted temperature rise values, obtained through the formula, slightly differed - within 10 percent - from the actual values based upon experiment results
10Â citations
01 Jun 1964
TL;DR: In this article, a theory has been developed based on the accepted heat transfer theories of Fishenden, Saunders, Weise and others, together with the results of the author's experiments.
Abstract: A theory has been developed based on the accepted heat transfer theories of Fishenden, Saunders, Weise and others, together with the results of the author's experiments. From this theory it is possible to evolve a design sheet which can be used to predict ambient temperatures within cabinets for predetermined areas of ventilation. Hence, design curves of temperature, in relation to areas of ventilation, can be obtained for specific cabinets and methods of cooling. From these curves, it should be possible to select the method of ventilation and the optimum cooling area and hence ensure that the maximum tolerable ambient temperature in which the components are required to operate shall not be exceeded.The effects on the hottest component, when the methods of ventilation are altered, the ventilating area is varied and the main heat source is progressively raised, are studied. The results of these experiments and the comparisons between predicted and observed ambient temperatures are discussed. Recommendation...
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