scholarly journals Analysis of the Thermal Characteristics of a Composite Ceramic Product Filled with Phase Change Material

Buildings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 217 ◽  
Author(s):  
Joanna Krasoń ◽  
Przemysław Miąsik ◽  
Lech Lichołai ◽  
Bernardeta Dębska ◽  
Aleksander Starakiewicz
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Transfer Coefficient ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Phase Change Material ◽  
Thermal Characteristics ◽  
Ceramic Product ◽  
Change Material ◽  
The Heat Transfer Coefficient

The article presents a comparative analysis carried out using three methods, determining the heat transfer coefficient U for a ceramic product modified with a phase change material (PCM). The purpose of the article is to determine the convergence of the resulting thermal characteristics, obtained using the experimental method, numerical simulation, and standard calculation method according to the requirements of PN-EN ISO 6946. The heat transfer coefficient is one of the basic parameters characterizing the thermal insulation of a building partition. Most often, for the thermal characteristics of the partition, we obtain from the manufacturer the value of the thermal conductivity coefficient λ for individual homogeneous materials or the heat transfer coefficient U for the finished (prefabricated) partition. In the case of a designed composite element modified with a phase change material or other material, it is not possible to obtain direct information on the above parameter. In such a case, one of the methods presented in this article should be used to determine the U factor. The U factor in all analyses was determined in stationary conditions. Research has shown a significant convergence of the resulting value of the heat transfer coefficient obtained by the assumed methods. Thanks to obtaining similar values, it is possible to continue tests of thermal characteristics of partitions by means of numerical simulation, limiting the number of experimental tests (due to the longer test time required) in assumed different partition configurations, in stationary and dynamic conditions.

scholarly journals Modeling the Heat Transfer Coefficient Between a Surface and Fixed and Fluidized Beds With Phase Change Material

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
María A. Izquierdo-Barrientos ◽  
C. Sobrino ◽  
José A. Almendros-Ibáñez
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Phase Change Material ◽  
Fluidized Beds ◽  
Convective Heat Transfer Coefficient ◽  
Superficial Gas Velocity ◽  
Change Material ◽  
The Heat Transfer Coefficient

The objective of this work is to model the heat transfer coefficient between an immersed surface and fixed and bubbling fluidized beds of granular phase change material (PCM). The model consists of a two-region model with two different voidages in which steady and transient conduction problems are solved for the fixed and fluidized bed cases, respectively. The model is validated with experimental data obtained under fixed and fluidized conditions for sand, a common material used in fixed and fluidized beds for sensible heat storage, and for a granular PCM with a phase change temperature of approximately 50 °C. The superficial gas velocity is varied to quantify its influence on the convective heat transfer coefficient for both the materials. The model proposed for the PCM properly predicts the experimental results, except for high flow rates, which cause the contact times between the surface and particles to be very small and lead the model to overpredict the results.

A Simple Experiment on Heat Transfer Using a Phase Change Material

1996 ◽  
Vol 24 (2) ◽  
pp. 119-123
Author(s):  
A. Macías-Machín ◽  
V. Henríquez ◽  
A. Lozano
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Phase Change Material ◽  
Simple Experiment ◽  
Change Material ◽  
The Heat Transfer Coefficient

An experiment to calculate the heat transfer coefficient using a phase change material is described. The various tests use a naphthalene ball which changes from solid to gas. The technique is simple and inexpensive, and it is capable of yielding meaningful results. It will be seen that the heat transfer rises with the temperature and air flowrate. Also, students will be encouraged to analyse their own results and to find other variations to this experiment. This will considerably enhance the students' understanding of the processes at work.

Local, Instantaneous Heat Transfer Coefficients for Jet Impingement on a Phase Change Surface

1996 ◽  
Vol 118 (2) ◽  
pp. 334-342 ◽  
Author(s):  
A. P. Bhansali ◽  
W. Z. Black
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Stagnation Point ◽  
Phase Change Material ◽  
Local Variation ◽  
Dimensionless Time ◽  
Change Material ◽  
The Heat Transfer Coefficient

The local variation in the heat transfer coefficient for an axisymmetric, turbulent, submerged liquid jet impinging on a nonuniform boundary of a phase-change material is measured with an ultrasonic measurement technique. The time required for an acoustic wave to traverse the phase-change material is measured with an ultrasonic transducer and the time data are converted into local thickness profiles of the phase-change material via knowledge of the longitudinal acoustic velocity in the material. An energy balance at the melt interface between the impinging jet and the phase-change material is used in conjunction with the local thickness profile data to determine the local variation in the heat transfer coefficient. The phase-change material is originally flat, but its shape changes with time as the heated jet melts a complex shape into its surface. The heat transfer rate over the surface of the melting interface is shown to vary with time as a result of the changing shape of the phase change material. A deep cavity is melted into the solid at the stagnation point and secondary cavities are melted into the interface for certain jet flow rates and surface spacings between the jet nozzle and the melt interface. When secondary cavities are produced, secondary peaks in the local heat transfer coefficient are observed. The heat transfer data are formulated into two Nusselt number correlations that are functions of the dimensionless time, dimensionless radius, dimensionless jet-to-surface spacing, and jet Reynolds number. One correlation is formulated for all locations along the surface of the phase-change material except the stagnation point, and a second correlation is valid at the stagnation point.

scholarly journals A numerical model and validation of phase change material integrated thermoelectric radiant cooling panel

2019 ◽  
Vol 111 ◽  
pp. 01001
Author(s):  
Hansol Lim ◽  
Hye-Jin Cho ◽  
Seong-Yong Cheon ◽  
Soo-Jin Lee ◽  
Jae-Weon Jeong
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Numerical Model ◽  
Surface Temperature ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Phase Change Material ◽  
Overall Heat Transfer Coefficient ◽  
Radiant Cooling ◽  
Change Material

A phase change material based radiant cooling panel with thermoelectric module (PCM-TERCP) is proposed in this study. It consists of two aluminium panels, and phase change materials (PCMs) sandwiched between the two panels. Thermoelectric modules (TEMs) are attached to one of the aluminium panels, and heat sinks are attached to the top side of TEMs. PCM-TERCP is a thermal energy storage concept equipment, in which TEMs freeze the PCM during the night whose melting temperature is 16○C. Therefore, the radiant cooling panel can maintain a surface temperature of 16◦C without the operation of TEM during the day. Furthermore, it is necessary to design the PCM-TERCP in a way that it can maintain the panel surface temperature during the targeted operating time. Therefore, the numerical model was developed using finite difference method to evaluate the thermal behaviour of PCM-TERCP. Experiments were also conducted to validate the performance of the developed model. Using the developed model, the possible operation time was investigated to determine the overall heat transfer coefficient required between radiant cooling panel and TEM. Consequently, the results showed that a overall heat transfer coefficient of 394 W/m2K is required to maintain the surface temperature between 16○C to 18○C for a 3 hours operation.

Phase Change Material Particulate Flow Through a Rectangular Channel: Effect of Parachute-Shaped Particles on the Heat Transfer

2011 ◽  
Author(s):  
Laura Small ◽  
Fatemeh Hassanipour
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Heat Transfer Enhancement ◽  
Phase Change Material ◽  
Volume Fraction ◽  
Particulate Flow ◽  
Transfer Enhancement ◽  
Change Material

This study presents numerical simulations of forced convection with parachute-shaped encapsulated phase-change material particles in water, flowing through a square cross-section duct with top and bottom iso-flux surfaces. The system is inspired by the gas exchange process in the alveolar capillaries between the red blood cells (RBC) and the lung tissue. The numerical model was developed for the motion of elongated encapsulated phase change particles along a channel in a particulate flow where particle diameters are comparable with the channel height. Results of the heat transfer enhancement for the parachute-shaped particles are compared with the circular particles. Results reveal that the key role in heat transfer enhancement is the snugness movement of the particles and the parachute-shaped geometry yields small changes in heat transfer coefficient when compared to the circular ones. The effects of various parameters including particle diameter and volume-fraction, as well as fluid speed, on the heat transfer coefficient is investigated and reported in this paper.

Characterization of Thermal Properties and Heat Transfer Behavior of Microencapsulated Phase Change Material Slurry and Multiwall Carbon Nanotubes in Aqueous Suspension

2007 ◽  
Author(s):  
Jorge L. Alvarado ◽  
Charles Marsh ◽  
Curt Thies ◽  
Guillermo Soriano ◽  
Paritosh Garg
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Heat Transfer Coefficient ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Effective Thermal Conductivity ◽  
Phase Change Material ◽  
Microencapsulated Phase Change Material ◽  
Change Material

In the last decade, microencapsulated phase change material (MPCM) slurries have been proposed and studied as novel coolants for heat transfer applications. Such applications include electronics cooling, and secondary coolants in air conditioning systems among others. Experiments have shown that MPCM’s increase the overall thermal capacity of thermal systems by taking advantage of the phase change material’s latent heat of fusion. However, research has also shown that the overall heat transfer coefficient is diminished due to a reduction in the effective thermal conductivity and increased viscosity of the slurry. For this reason, there is an urgent need to modify the content of microcapsules containing phase change material to increase their effective thermal conductivity and the overall heat transport process. Our solution consists of increasing the thermal conductivity of MPCM by adding carbon nanotubes to the shell and core of the microcapsules. Carbon nanotubes have shown to increase the thermal conductivity of liquids by 40% or more in recent experiments. In this paper, MPCM slurry containing octadecane as phase change material and multi-wall carbon nanotubes (MWCNTs) embedded in the capsule material and core are compared with pure water as heat transfer fluid. Thermal and physical properties of MPCM slurry containing carbon nanotubes were determined using a differential scanning calorimeter and concentric viscometer, respectively. Experimental convective heat transfer coefficient data for MWCNT aqueous suspensions under laminar flow and constant heat flux were determined using a bench-top heat transfer loop. Experimental heat transfer results are presented.

Heat Transfer Enhancement by Slurry of Phase Change Material Through Rectangular Porous Channel

2011 ◽  
Author(s):  
Manali Shukla ◽  
Fatemeh Hassanipour
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Heat Transfer Coefficient ◽  
Phase Change ◽  
Phase Change Material ◽  
Heat Fluxes ◽  
Porous Channel ◽  
Transfer Enhancement ◽  
Change Material ◽  
The Heat Transfer Coefficient

This study attempts to take advantage of porous media with high conductivity and the latent heat capacity of phase change material together to enhance the overall heat transfer rate. A 3-D laminar model of a rectangular porous channel with high thermal conductivity and constant wall heat flux is chosen to see the enhancement of heat transfer when used in conjunction with the phase change material slurry. Numerical simulations for various wall heat fluxes and inlet velocities are carried out. The heat transfer coefficient along the heated surface of the channel is compared when adding micro-encapsulated phase change material to the flow passing through porous channel. There is a significant heat transfer enhancement when using phase change material slurry through porous channel, only under specific conditions of heat fluxes, inlet velocities and the particle concentrations. This study also investigates the effect of various porous media properties e.g. porosity and permeability on the heat transfer coefficient when applied with slurry of phase change material.

Numerical Analysis on Heat Transfer Characteristics of Looped Minichannel Using Phase-Change VOF Method

2013 ◽  
Author(s):  
Hajime Onishi ◽  
Motoya Kawamura ◽  
Yukio Tada ◽  
Akira Takimoto
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Transfer Coefficient ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Film Condensation ◽  
Film Boiling ◽  
Heat Transfer Characteristics ◽  
The Heat Transfer Coefficient ◽  
Good Agreement

This study develops a numerical simulation of liquid-vapor two phase flows accompanied with the phase change. In the developed simulation, the VOF (Volume of Fluid) method is adopted for tracking the liquid-vapor interface and the temperature recovery method for estimating mass transfer due to the phase change. Firstly, the numerical simulation is performed for film-boiling and film-condensation problems for validating the evaporation (boiling) and condensation calculation. The numerical result for the film-boiling problem is in good agreement with the Berenson’s semi-empirical correlation in terms of the heat transfer coefficient. Moreover, the numerical results for the film-condensation problem are also in good agreement with the theoretical analysis by Nusselt in terms of the film growth rate and the heat transfer coefficient. These have confirmed the reliability of the developed simulation. Then, the developed simulation is applied to investigate the heat transfer characteristics of the heat transport device with a pump-driven looped minichannel. The result reveals a new interesting feature of the minichannel heat device.

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