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Journal ArticleDOI

Application of phase change materials for passive thermal control of plastic quad flat packages (PQFP): a computational study

07 Feb 1995-Vol. 30, Iss: 1, pp 19-34
TL;DR: In this paper, a transient three-dimensional analysis was performed for passive thermal control of a plastic quad flat package (PQFP) by incorporating phase change material (PCM) under the printed wiring board (PWB).
Abstract: A transient three-dimensional analysis was performed for passive thermal control of a plastic quad flat package (PQFP) by incorporating phase change material (PCM) under the printed wiring board (PWB). Governing conservation equations for mass, momentum and energy were solved by an implicit finite volume numerical technique. The effects of phase change were modelled by a single domain enthalpy-porosity technique. To study the effects of thermal conductivity of the board, a total of four cases were considered with two different board materials. It was found that passive cooling with PCM can arrest the temperature rise for a substantial time, for the power level considered. A higher board thermal conductivity resulted in a reduction in temperature levels. The melt region for a lower thermal conductivity of the board was found to be localized near the package footprint, while, for a higher board conductivity, the melt region extends along the board.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a review of the history of thermal energy storage with solid-liquid phase change has been carried out and three aspects have been the focus of this review: materials, heat transfer and applications.

4,019 citations

Journal ArticleDOI
TL;DR: The use of a latent heat storage system using Phase Change Materials (PCM) is an effective way of storing thermal energy (solar energy, off-peak electricity, industrial waste heat) and has the advantages of high storage density and the isothermal nature of the storage process as discussed by the authors.
Abstract: The use of a latent heat storage system using Phase Change Materials (PCM) is an effective way of storing thermal energy (solar energy, off-peak electricity, industrial waste heat) and has the advantages of high storage density and the isothermal nature of the storage process. It has been demonstrated that, for the development of a latent heat storage system, choice of the PCM plays an important role in addition to heat transfer mechanism. The information on the latent heat storage materials and systems is enormous and published widely in the literatures. In this paper, we make an effort to gather the information from the previous works on PCMs and latent heat storage systems. This review will help to find a suitable PCM for various purposes a suitable heat exchanger with ways to enhance the heat transfer, and it will also help to provide a variety of designs to store the heat using PCMs for different applications, i.e. space heating & cooling, solar cooking, greenhouses, solar water heating and waste heat recovery systems. Measurement techniques of thermophysical properties, studies on thermal cycles for long term stability, corrosion of the PCMs and enhancement of heat transfer in PCM are discussed. New PCM innovations are also included for the awareness of new applications. This paper contains a list of about 250 PCMs and more than 250 references.

638 citations


Cites background from "Application of phase change materia..."

  • ...Pal and Joshi (1996 ; 1997 ) recommended the PCM to restrict the maximum temperature of electronic components....

    [...]

Journal ArticleDOI
25 Sep 2006
TL;DR: A brief discussion of key sources of power dissipation and their temperature relation in CMOS VLSI circuits, and techniques for full-chip temperature calculation with special attention to its implications on the design of high-performance, low-power V LSI circuits is presented.
Abstract: The growing packing density and power consumption of very large scale integration (VLSI) circuits have made thermal effects one of the most important concerns of VLSI designers The increasing variability of key process parameters in nanometer CMOS technologies has resulted in larger impact of the substrate and metal line temperatures on the reliability and performance of the devices and interconnections Recent data shows that more than 50% of all integrated circuit failures are related to thermal issues This paper presents a brief discussion of key sources of power dissipation and their temperature relation in CMOS VLSI circuits, and techniques for full-chip temperature calculation with special attention to its implications on the design of high-performance, low-power VLSI circuits The paper is concluded with an overview of techniques to improve the full-chip thermal integrity by means of off-chip versus on-chip and static versus adaptive methods

420 citations

Journal ArticleDOI
TL;DR: In this article, a review of recent research in Building Integrated Photovoltaics (BIPV) is presented with the emphases on a range of key systems whose improvement would be likely to lead to improved solar energy conversion efficiency and/or economic viability.

318 citations

Journal ArticleDOI
TL;DR: In this paper, a theoretical model was formulated to estimate the overall latent energy of the samples with the variation in volume fraction of the nanoparticles, and the predicted values of latent energy from the model showed good agreement with the experimental results.
Abstract: Latent energy storage capacity was analyzed for a system consisting of carbon nanoparticles doped phase change materials (PCMs). Three types of samples were prepared by doping shell wax with single wall carbon nanotubes (SWCNTs), multiwall CNTs, and carbon nanofibers. Differential scanning calorimetry was used to measure the latent heat of fusion. The measured values of latent heat for all the samples showed a good enhancement over the latent heat of pure wax. A maximum enhancement of approximately 13% was observed for the wax/SWCNT composite corresponding to 1% loading of SWCNT. The change in latent heat was modeled by using an approximation for the intermolecular attraction based on the Lennard-Jones potential. A theoretical model was formulated to estimate the overall latent energy of the samples with the variation in volume fraction of the nanoparticles. The predicted values of latent energy from the model showed good agreement with the experimental results. It was concluded that the higher molecular ...

204 citations

References
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Book
01 Jan 1980
TL;DR: In this article, the authors focus on heat and mass transfer, fluid flow, chemical reaction, and other related processes that occur in engineering equipment, the natural environment, and living organisms.
Abstract: This book focuses on heat and mass transfer, fluid flow, chemical reaction, and other related processes that occur in engineering equipment, the natural environment, and living organisms. Using simple algebra and elementary calculus, the author develops numerical methods for predicting these processes mainly based on physical considerations. Through this approach, readers will develop a deeper understanding of the underlying physical aspects of heat transfer and fluid flow as well as improve their ability to analyze and interpret computed results.

21,858 citations

Journal ArticleDOI
TL;DR: In this article, the melting of pure gallium in a rectangular cavity has been numerically investigated using the enthalpy-porosity approach for modeling combined convection-diffusion phase change.
Abstract: The melting of pure gallium in a rectangular cavity has been numerically investigated using the enthalpy-porosity approach for modeling combined convection-diffusion phase change. The major advantage of this technique is that it allows a fixed-grid solution of the coupled momentum and energy equations to be undertaken without resorting to variable transformations. In this work, a two-dimensional dynamic model is used and the influence of laminar natural-convection flow on the melting process is considered. Excellent agreement exists between the numerical predictions and experimental results available in the literature. The enthalpy-porosity approach has been found to converge rapidly, and is capable of producing accurate results for both the position and morphology of the melt front at different times with relatively modest computational requirements. These results may be taken to be a sound validation of this technique for modeling isothermal phase changes in metallurgical systems.

1,377 citations

Proceedings ArticleDOI
H.I. Rosten, Ram S. Viswanath1
01 May 1994
TL;DR: In this article, a component manufacturer and a thermal analysis software vendor working together to construct and validate a thermal model of first-level packaging of a die (the Pentium processor) are presented.
Abstract: Large mono-chip packages show a trend of increasing power dissipation and power density: for example the maximum dissipation of the Pentium processor is 16 Watts compared to the 6 Watts of its 80486 predecessor. This poses challenges for equipment designers to provide satisfactory thermal environments for reliable package operation. This paper provides an example of a component manufacturer and a thermal-analysis software vendor working together to construct and validate a thermal model of first-level packaging of a die (the Pentium processor) that can be used by equipment designers concerned with second- and third-level packaging. It is proposed that this example might set a pattern for the future. >

36 citations

ReportDOI
01 Oct 1990
TL;DR: In this article, the energy equation is formulated in terms of enthalpy and discretized using a finite-difference method, which can be used to analyze heat conduction in a rectangular region undergoing an isothermal phase change.
Abstract: Finding new and improved means of cooling small electronic packages are of great importance to today's electronic packaging engineer. Thermal absorption through the use of a material which changes phase is an attractive alternative. Taking advantage of the heat capacity of a material's latent heat of fusion is shown to absorb heat away from the electronics, thus decreasing the overall temperature rise of the system. The energy equation is formulated in terms of enthalpy and discretized using a finite-difference method. A FORTRAN program to solve the discretized equations is presented which can be used to analyze heat conduction in a rectangular region undergoing an isothermal phase change. An analysis of heat transfer through a miniature radar electronic module cooled by a phase-change reservoir is presented, illustrating the method's advantages over conventional heat sinks. 41 refs., 11 figs., 2 tabs.

14 citations