Electronic Equipment Casings Research Articles

Additive Manufacturing of Waste Electrical and Electronic Equipment (WEEE) Produced From Acrylonitrile Butadiene Styrene (ABS)

Objective: To evaluate the feasibility of producing recycled acrylonitrile-butadiene-styrene (r-ABS) filaments from waste electrical and electronic equipment (W EEE) casings, specifically discarded monitors and televisions, and to compare their properties with those of virgin ABS. Theoretical Framework: The research was based on a literature review of additive manufacturing, WEEE recycling, and the thermal, mechanical, rheological, and microscopic characterizations of recycled polymers, with an emphasis on fused deposition modeling (FDM). Method: WEEE casings were collected and mechanically recycled to produce r-ABS filaments. These filaments were characterized and compared with virgin ABS filaments using infrared spectroscopy (FTIR), thermal analyses (TGA and DSC), rheological, mechanical, and microscopic evaluations. Results and Conclusion: The results indicated that r-ABS filaments exhibit properties comparable to those of virgin ABS. FTIR analysis revealed the presence of the main functional groups of ABS in the recycled samples. Thermal analysis showed similar behavior between the recycled and virgin materials, with a single thermal decomposition event. Rheological analysis demonstrated that r-ABS possesses viscoelastic properties suitable for the FDM process, and mechanical characterization showed that r-ABS exhibited tensile strength close to virgin ABS. Microscopic analysis revealed good layer adhesion and a low number of voids, factors that contribute to the quality of the printed objects. Research Implications: This study contributes to the valorization of polymeric waste, promoting the use of recycled materials in additive manufacturing processes, which can benefit both the environment and the 3D printing industry. Originality/Value: The research addresses a topic still underexplored in the literature, especially concerning the recycling of WEEE casings for the production of ABS filaments.

Study on the natural air cooling design of electronic equipment casings: Effects of the height and size of outlet vent on the flow resistances

This paper describes the effects of the outlet vent size and the distance between the outlet vent location and the power heater position on the flow resistance in natural-air-cooled electronic equipment casings. An experiment was carried out using a simple model casing simulated for the practical natural-air-cooled casing which is composed of 4 side walls, a top plate and bottom plate which has an inlet opening. A power heater to served as a power dissipation unit was placed at its open bottom. An outlet opening was set on one of the side walls. The opening area, the height of the outlet and the heater location were varied. The experimental results were analyzed using the flow resistance coefficient K which was related to the distance between the outlet vent and the power heater position and the heat removal from the outlet vent, and K values were plotted against a pair of Reynolds numbers Re and the outlet vent porosity β which is defined as the ratio of outlet vent open area to the top surface area of the casing.

Study on the chimney effect in natural air‐cooled electronic equipment casings under inclination: Proposal of a thermal design correlation that includes the porosity coefficient of an outlet opening

AbstractNatural air‐cooling technologies for electronic equipment have the important advantages of no fan and high reliability. However, natural air cooling has lower cooling capability than fan air cooling, so enhancement of its cooling capability is required. This paper presents the results for experimental casings designed to employ the chimney effect in natural air‐cooled electronic equipment. The system casing is inclined to enhance the effectiveness of natural air cooling. Experiments were carried out using a thin laptop PC. We investigated the effect on cooling capability produced by inclining the casing and by varying the outlet positions and numbers and the porosity coefficient of the outlet openings. The results show that the temperatures inside the casing and heater surfaces are slightly diminished by the effect of increased inclination and porosity coefficient of outlet openings. Moreover, the increase in natural circulation flux in the casing was quantitatively proven by experiments. In addition, the experimental data were reduced to a Nusselt number–Rayleigh number correlation, $Nu_{\beta}^{\ast}=0.432Ra_{\beta}^{\ast0.322}$, by using a modified reference length. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(2): 122–136, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20103

Study on Chimney Effect in Natural Air Cooled Electronic Equipment Casings under Inclination (2nd Report, The Proposal of a Thermal Design Correlation including Porosity Coefficient of an Outlet Opening)

Natural air cooling technologies of electronic equipment have important advantages of no fan and high reliability. However, natural air cooling has lower cooling capability than fan air cooling, so the cooling capability enhancement has been required. In this paper are presented the results of the experimental casings on the chimney effect in natural air-cooled electronic equipment. The system box is inclined for the purpose to enhance the capability of natural air-cooling. Experiments have been carried out using a model of thin laptop PC. The influence of the box inclination, outlet positions and numbers, and the porosity coefficient of outlet openings on the cooling capability was investigated. The results show that the temperature values inside casing and heater surface are gently diminished by the effect of increase in inclination and porosity coefficient of outlet openings. Moreover, the increase in natural circulation flux in the box is quantitatively proven by experiments. The experimental data were reduced to a Nusselt number-Rayleigh number correlation by using modified the reference length.

Study on Chimney Effect in Natural Air Cooled Electronic Equipment Casings under Inclination (The Proposal of a Thermal Design Correlation with Inclination)

Natural air-cooling needs neither a fan nor a blower. However, cooling capability of natural air-cooling is low, so the improvement of its capability is indispensable. In this paper are presented the results of the experimental casings on the chimney effect in natural air-cooled electronic equipment. The system box is inclined for the purpose to raise the capability of natural air-cooling. Experiments have been carried out using three models of thin laptop PC that have two kinds of heat sources. It has inlet and outlet vents on the front and rear walls of the casing. The box was inclined 0 to 90 degrees up from the horizontal plane. The influence by the box inclination, the box dimensions, and the heating element size was investigated. The result shows that the temperature inside casing and heater surface temperature are gently diminished by the effect of inclination, and the increase in natural circulation flux in the box is quantitatively proven by experiments. But, a substantial benefit of casing inclination is only at angles lower than about 40 degree. In the other hand, the experimental data were reduced to a Nusselt number-Rayleigh number correlation by using modified the reference length we supposed that does not include explicitly the box dimensions, the heat source size, and the inclination angle. The experimental data almost fall on a straight line which gives a correlation Nu* =0.0038 Ra*0.6, and are collapsed in a narrow band.

自然空冷機器における障害物が及ぼす流体抵抗の影響(J01-5 筐体放熱設計,J01 エレクトロニクス実装における熱制御および信頼性評価)

自然空冷機器における障害物が及ぼす流体抵抗の影響(J01-5 筐体放熱設計,J01 エレクトロニクス実装における熱制御および信頼性評価)

Sealing electronic equipment casings

Dr Emily Ho, BHR Group Ltd, Cranfield, Bedford, UK A number of recent news items in Sealing Technology have featured seal developments by manufacturers of seals for electronic equipment, particularly for communications. The sealing of casings for communication equipment may sound at first to be relatively simple, but this is far from the case as this feature article explains.

C165 自然空冷筐体の冷却に対する内部実装密度の影響

C165 自然空冷筐体の冷却に対する内部実装密度の影響

Study on the natural air cooling of electronic equipment casings: Effects of the outlet vent and the power heater locations on the cooling capability

This paper is concerned with the natural cooling of electronic equipment casings. Effects of the size and the location of the outlet vent as well as the relative distance from the outlet vent location to the power heater position on the flow resistance have been investigated experimentally by using a simple model casing simulated for practical natural air cooled electronic equipment casings. The result shows that the mean temperature rise inside the casing increases with increase in the heater input power, but decreases linearly with increase in the vent porosity coefficient in logarithmic coordinates. As the heater approaches the outlet vent, the temperature rise increases linearly in the logarithmic scale. By defining a new dimensionless parameter called the equivalent Reynolds number, involving the Reynolds number and the porosity coefficient, the flow resistance coefficient is found to have a close logarithmic linear correlation, K = kxχ−1.5, with the equivalent Reynolds number. Its validation has been proved by the good agreement with experimental results. The result indicates that the relative distance from the outlet vent to the heat dissipation unit can be considered as a chimney height in the practical engineering design. Although further more detailed validations are needed, a useful correlation between the flow resistance coefficient, the Reynolds number and the porosity coefficient has been presented for the design application of natural cooling electronic casings.

K-1833 自然空冷式電子機器筐体からの放熱 : 流体抵抗に対する出口窓の位置と形状の影響(G06-8 熱工学(8) : 体積力対流)(G06 熱工学部門一般講演)

K-1833 自然空冷式電子機器筐体からの放熱 : 流体抵抗に対する出口窓の位置と形状の影響(G06-8 熱工学(8) : 体積力対流)(G06 熱工学部門一般講演)

The effects of the outlet area and the location of the main power supply unit on the cooling capability through naturally air-cooled electronic equipment casings

This paper describes a practical thermal design approach to natural air-cooled electronic equipment casings. A set of simplified equations for the thermal design of natural air-cooled electronic equipment casings has been proposed. The proposed set of equations satisfied the demand of practical air-cooling systems, since it takes account of factors such as the stack effect, the air flow resistance and the heat transfer due to natural convection. The effects of the outlet area and the location of the main power supply unit on the natural cooling capability of electronic equipment casings were studied using a set of equations. The results have shown that a uniform temperature distribution could be achieved when the main power supply unit was placed at the bottom of the casing. It has also been suggested that the value of the heat removed from the casing surface could be more significant than that from the outlet vent in the thermal design of natural air-cooled electronic equipment casings.

Air Flow Resistance of Wire Nettings in Natural Convection

This paper describes some experimental values for flow resistance of wire nettings in low Reynolds number flows, such as natural air convection, providing basic thermal data necessary for designing electronic equipment casings. The experiment was designed to evaluate the wire netting resistance coefficient in natural air convection. As a result, the relationships among the resistance coefficient for wire netting, Reynolds number, and porosity coefficient were obtained in useful form.

On the Cooling of Natural-air-cooled Electronic Equipment Casings : Proposal of a Practical Formula for Thermal Design

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.

Flow resistance for wire nettings in low Reynolds number flows.

This paper describes some experimental values of flow resistance for wire nettings in low Reynolds number flows, such as air natural convections, providing basic thermal data necessary for designing electronic equipment casings. The experiment was designed to evaluate resistance coefficients, depending on the air temperature increased by the combined effect of motive powers for natural convection and flow resistance for wire nettings, because measurements for pressure losses and velocities in low Reynolds number flows using conventional methods are very difficult. As a result, the following relationship was obtained from a practical point of view: K=28(R<ed>·β2/1-β)-0.95, 0.4<Red<95 where K is the resistance coefficient. Red is Reynolds number based on the wire diameter and β is porosity coefficient for wire nettings.

On the cooling of natural-air-cooled electronic equipment casings (Proposal of a practical formula for thermal design)

This paper presents a simple formula for thermal designing of natural-air-cooled electronic equipment casings with standard arrangement for circuit boards and power supplies. The formula meets the requirements as a practical formula, since it represents the air-cooling system in its simplified form with due regard to such factors as the stack effects, air Flow resistance, natural convective transfer and so on. The formula was applied to predict temperature rise for two practically used electronic equipment cabinets with standard arrangements and a modeling case. The predicted temperature rise values, obtained through the formula, caused very slight errors, with only 10 percent in the actual values based upon experiment results.

Aerodynamic Resistance of Perforated Plates in Natural Convection

This paper describes some experimental values of aerodynamic resistance of perforated plates in natural convection, providing basic thermal data necessary for designing electronic equipment casings. In the conventional measuring method which measures only in the higher region of Reynolds number, there is a disadvantage that the utmost precision cannot be attained in measurement due to the values of pressure loss and velocity being unidentifiably small. Io our new method, however, it is designed to evaluate a fluid resistance coefficient depending on the air temperature elevated by the combined effect of motive power of natural convection and fluid resistance and consequently to elucidate the influence of Reynolds number, coefficient of porosity, and thickness of plates/diameter of holes on resistance coefficient of perforated plates.

Aerodynamic Resistance of Perforated Plates in Natural Convection

This paper describes some experimental values of aerodynamic resistance of perforated plates in natural convection, providing basic thermal data necessary for designing electronic equipment casings. In the conventional measuring method which measures only in the higher region of Reynolds number, there is a disadvantage that the utmost precision cannot be attained in measurement due to the values of pressure loss and velocity being unidentifiably small. Io our new method, however, it is designed to evaluate a fluid resistance coefficient depending on the air temperature elevated by the combined effect of motive power of natural convection and fluid resistance and consequently to elucidate the influence of Reynolds number, coefficient of porosity, and thickness of plates/diameter of holes on resistance coefficient of perforated plates.