Mathematical Model of Multi-Layer Wall with Phase Change Material and its Use in Optimal Design

2013 ◽  
Vol 649 ◽  
pp. 295-298
Author(s):  
Lubomir Klimes ◽  
Pavel Charvát ◽  
Josef Stetina
Keyword(s):  
Mathematical Model ◽  
Optimal Design ◽  
Phase Change ◽  
Phase Change Material ◽  
Control Volume ◽  
Operational Conditions ◽  
Volume Method ◽  
The Mathematical Model ◽  
Change Material

The paper deals with the mathematical model of the multi-layer wall containing the phase change material (PCM). The model utilizes the effective heat capacity method for modeling the latent heat of phase change and the control volume method is used for the discretization of the model. The utilization of the model is then demonstrated on the problem of the optimal design of the multi-layer wall with the PCM. The TMY2 data for the city of Brno were used in simulations as operational conditions. The main attention is aimed at the determination of the optimal thickness of the PCM layer for the multi-layer wall design with various thicknesses of the masonry.

Numerical Survey of the Melting Driven Natural Convection Using Generation Heat Source: Application to the Passive Cooling of Electronics Using Nano-Enhanced Phase Change Material

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Hamza Faraji ◽  
Mustapha Faraji ◽  
Mustapha El Alami
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Source ◽  
Phase Change ◽  
Phase Change Material ◽  
Metallic Nanoparticles ◽  
Simple Algorithm ◽  
Bottom Side ◽  
Volume Method ◽  
Change Material

Abstract The present paper reports numerical results of the melting driven natural convection in an inclined rectangular enclosure filled with nano-enhanced phase change material (NePCM). The enclosure is heated from the bottom side by a flush-mounted heat source (microprocessor) that generates heat at a constant and uniform volumetric rate and mounted on a substrate (motherboard). All the walls are considered adiabatic. The purpose of the investigation is analyzing the effect of nanoparticles insertion by quantifying their contribution to the overall heat transfer. Combined effects of the PCM type, the inclination angle and the nanoparticles fraction on the structure of the fluid flow and heat transfer are investigated. A 2D mathematical model based on the conservation equations of mass, momentum, and energy was developed. The governing equations were integrated and discretized using the finite volume method. The SIMPLE algorithm was adopted for velocity–pressure coupling. The obtained results show that the nanoparticles insertion has an important quantitative effect on the overall heat transfer. The insertion of metallic nanoparticles with different concentrations affects the thermal behavior of the heat sink. They contribute to an efficient cooling of the heat source. The effect of nanoparticles insertion is also shown at the temperature distribution along the substrate.

Optimal Design of HFC Solar Plant by Using Phase Change Material for Heat Storage

2015 ◽  
Vol 806 ◽  
pp. 203-213
Author(s):  
Tina Kegl
Keyword(s):  
Power Plant ◽  
Optimal Design ◽  
Phase Change ◽  
Phase Change Material ◽  
Heat Storage ◽  
Economic Point ◽  
Storage Materials ◽  
Heat Storage Materials ◽  
Solar Receiver ◽  
Change Material

This paper deals with an optimal design solar tower power plant. Special attention is focused on the central receiver system and heat storage materials. In order to get an effective power plant, a simple mathematical model to calculate the solar energy, concentrated on the solar receiver during one year, is developed. The model can predict the delivered energy in dependence on the arrangement of the heliostats and the height of the solar receiver. By using an optimizer, a plant of 5 MW power is optimized in order to produce a maximum of electrical energy during the year on the prescribed area. On the basis of analysis of heat storage materials, KNO3, acting as phase change material (PCM), is shown to be suitable for heat storage from the thermal, physical, kinetic, chemical, and economic point of view.

scholarly journals Melting Within a Spherical Enclosure

1982 ◽  
Vol 104 (1) ◽  
pp. 19-23 ◽  
Author(s):  
F. E. Moore ◽  
Y. Bayazitoglu
Keyword(s):  
Mathematical Model ◽  
Energy Storage ◽  
Flow Field ◽  
Phase Change ◽  
Experimental Evidence ◽  
Phase Change Material ◽  
Saturation Temperature ◽  
Temperature Profiles ◽  
Change Material ◽  
Storage Characteristics

Melting of a phase change material within a spherical enclosure is considered. The phase change material is initially at its saturation temperature. Suddenly the enclosure temperature is increased to a fixed value. The density of the solid is assumed to exceed the density of the liquid, the implication being that the solid continually drops toward the bottom of the shell as melting progresses. This motion of the solid generates a flow field within the liquid. A mathematical model is developed and confirmed by experimental evidence. The interface positions and the temperature profiles for various Stefan and Fourier numbers are determined, and the energy storage characteristics are studied. It is found that the convective effects can be neglected only at small Stefan numbers.

Phase Change Material Freezing in an Energy Storage Module for a Micro Environmental Control System

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
H. Ezzat Khalifa ◽  
Mustafa Koz
Keyword(s):  
Mathematical Model ◽  
Phase Change ◽  
Phase Change Material ◽  
Environmental Control ◽  
Finite Thickness ◽  
Element Model ◽  
Storage Device ◽  
Freezing Process ◽  
Latent Heat Storage ◽  
Change Material

Abstract This study analyzes phase change material (PCM) freezing process in a novel latent heat storage device (LHSD). Heat is removed from the PCM with an embedded evaporator. A mathematical model of freezing in a finite-thickness PCM slab is presented. An experimentally validated reduced-order model (ROM) based on the mathematical model was developed to analyze the heat transfer between the freezing PCM and an evaporating refrigerant flowing inside a flat, microchannel tube coil embedded in the PCM. A detailed finite element model (FEM) of the same device was also developed and employed to verify the validity of the ROM over a wider range of conditions. The freezing times and total “cooling” stored in the PCM computed by the ROM agree very well with those computed by the detailed FEM. The ROM executes in ∼1 min for a full heat exchanger, compared with more than 10 h for the FEM, making the former much more practical for use in parametric analysis and optimization of design alternatives.

Response Characteristic of Internal Surface of Phase Change Wall on Outdoor Temperature Changes

2012 ◽  
Vol 629 ◽  
pp. 448-454
Author(s):  
Quan Ying Yan ◽  
Li Li Jin ◽  
Li Hang Yue ◽  
Zheng Bang Ruan
Keyword(s):  
Mathematical Model ◽  
Phase Change ◽  
Phase Change Material ◽  
Internal Surface ◽  
Response Characteristic ◽  
Outdoor Temperature ◽  
Temperature Changes ◽  
Common Wall ◽  
Change Material

In the paper, mathematical model of phase change wall prepared by different ways and common wall was built and simulated by ANSYS. Response characteristic of internal surface of phase change material wall on outdoor temperature changes was studied when phase change material was added into the wall by different ways. Results in this paper can provide the basis for the application of the wall with phase change material.

Numerical and Experimental Investigation of Shell-and-Tube Phase Change Material Thermal Storage Unit

2015 ◽  
Author(s):  
Thomas H. Sherer ◽  
Yogendra Joshi
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Control Volume ◽  
Heat Transfer Fluid ◽  
Transient Temperature ◽  
Storage Unit ◽  
Tube Bank ◽  
Fully Implicit ◽  
Shell And Tube ◽  
Change Material

A shell-and-tube phase change material (PCM) thermal energy storage (TES) unit has been analyzed numerically and experimentally. The tube bank is filled with commercial paraffin RUBITHERM RT 28 HC PCM, which melts as the heat transfer fluid (HTF) flows across the tubes. A fully-implicit one-dimensional control volume formulation that utilizes the enthalpy method for phase change has been developed to determine the transient temperature distributions in both the PCM and the tubes themselves. The energy gained by a column of tubes is used to determine the exit bulk HTF temperature from that column, ultimately leading to an exit HTF temperature from the TES unit. This paper presents a comparison of the numerical and experimental results for the transient temperature profiles of the PCM-filled tubes and HTF.

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