An analytical solution of the heat transfer process during melting of an unfixed solid phase change material inside a horizontal tube

Bareiss, M.; Beer, H.

doi:10.1016/0017-9310(84)90143-1

Cited by 150 publications

(40 citation statements)

References 9 publications

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“…For the melting process in a horizontal tube with natural convection in the liquid phase, there are two different models of melting: fixed melting (Ho and Viskanta, 1984) and unfixed melting (Bareiss and Beer, 1984). The only difference between these two models is that the unmelted solid PCM either remains at the center of the tube or falls downward due to the effect of gravity.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Freezing in an Eccentric Annulus

Zhang

Faghri

1997

Journal of Solar Energy Engineering

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Section: Introductionmentioning

confidence: 99%

Analysis of Freezing in an Eccentric Annulus

Zhang

Faghri

1997

Journal of Solar Energy Engineering

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“…Using the calculated external and internal heat transfer coefficients, the heat transfer capacity of the module is determined using the method of Number of Transfer Units (NTU-Method) [11,10]. The actual heat transfer in the module is calculated according to (Equation 9 to 11).…”

Section: Determination Of the Heat Capacity Of The Modulementioning

confidence: 99%

Methodology for the design of a thermal energy storage module for asolar tunnel dryer using phase change materials (PCM)

Escobar-Ochoa

Cuervo-Andrade

Rincon-Prat³

2018

revuin

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Este artículo puede compartirse bajo la licencia CC BY-ND 4.0 y se referencia usando el siguiente formato: M. Escobar, S. Cuervo, S. Rincón, "Methodology for the design of a thermal energy storage module for a solar tunnel dryer using phase change materials (PCM)," Rev. UIS Ing., vol. 17, no. 1, pp. 9-20, 2018. Doi: https://doi.org/10.18273/revuin.v17n1-2018001 Vol. 17, No. 1, pp. 9-20, enero-junio 2018 Revista UIS Ingenierías ABSTRACTThe increasing interest in renewable energy has opened an opportunity to apply this technology in the industry and domestic sector. However, in solar-based systems, limitations associated with the intermittent energy delivery can cause unstable performance and unreliable designs. Weather fluctuations, such as wind speed and appearance of clouds, are considered the principal factors that contribute to the instability in the amount of energy available. In the agriculture, for instance, the use of thermal solar energy applied to dryer systems is highly desirable since the process is energetically very intensive. Therefore, it is feasible to design dryer devices for agricultural products, with important economic returns due to energy savings and the value added to the materials processed. Thus, the energy performance of systems that operate with solar thermal energy can be improved by introducing an energy accumulation system based on the use of phase change materials (PCM). The detailed methodology for the design of a thermal energy accumulation system for a tunnel dryer type Hohenheim for agricultural products is presented. As PCM, paraffin is chosen because its melting temperature is near 60 °C, which is an appropriate value for the drying temperature of this kind of products. The theoretical calculations show that the value of the surface temperature has an important influence on phase change calculations and the total mass of PCM required in the system. On the other hand, the heat transfer is dominated by the external heat transfer in the air. Additionally, the tube diameter significantly affects the phase change time. The results obtained are important and make a significant contribution to the knowledge required for implementations of similar systems, since little has been explored in this field in regions where the weather conditions are suitable to unexpected changes. The design should be implemented in an experimental prototype of Hohenheim dryer and its performance is to be determined based on measurement of the energy change of the drying air.KEYWORDS: Renewable energy; solar dryer; PCM; heat transfer. RESUMENEl creciente interés en las energías renovables ha abierto una oportunidad para aplicar esta tecnología en la industria y el sector nacional. Sin embargo, en sistemas basados en energía solar, las limitaciones asociadas con la entrega de energía intermitente pueden causar un rendimiento inestable y diseños poco confiables. Las fluctuaciones climáticas, como la velocidad del viento y la apariencia de las nubes, se consideran los principales factores que contribuyen...

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“…In this case contact melting occurs as the frozen solid melts due to contact with the hot container wall. 2, [7][8][9] Many examples of contact melting are provided in the review of Bejan. 10 Perhaps the two most familiar examples of contact melting are the Leidenfrost effect and ice skating.…”

Section: Introductionmentioning

confidence: 99%

Unsteady contact melting of a rectangular cross-section material on a flat plate

2008

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The work in this paper concerns a mathematical model of the contact melting process of a rectangular material in contact with a hot plate. The problem is described by a coupled system of heat equations in the solid and melt layer, fluid flow in the melt, a Stefan condition at the melt interface, and a force balance between the weight of the solid and the fluid pressure. Since the melt layer remains thin throughout the process, we use the lubrication approximation to the fluid equations and assume that the heat flow in the fluid is dominated by conduction across the thin film. In the solid we employ a heat balance integral method. Results show that the film height has initial and final rapid increases, whereas for intermediate times the height slowly increases. The quasisteady state of previous models is never attained: This is shown to be an effect of neglecting the change in mass and conduction in the solid. The previously observed initial infinite velocity of the melt is shown to be a result of the perfect thermal contact assumption. For a water-ice system the melting rate is shown to be approximately linear, this allows us to reduce the problem to solving a single first order differential equation for the liquid layer thickness. The main analysis is carried out in two dimensions, but we briefly highlight the extension to three dimensions. The method is verified by comparison with previously published experimental results on the melting of n-octadecane.

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An analytical solution of the heat transfer process during melting of an unfixed solid phase change material inside a horizontal tube

Cited by 150 publications

References 9 publications

Analysis of Freezing in an Eccentric Annulus

Analysis of Freezing in an Eccentric Annulus

Methodology for the design of a thermal energy storage module for asolar tunnel dryer using phase change materials (PCM)

Unsteady contact melting of a rectangular cross-section material on a flat plate

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