Thermal Analysis of Composite Phase Change Drywall Systems

2004 ◽  
Vol 127 (3) ◽  
pp. 352-356 ◽  
Author(s):  
K. Darkwa ◽  
J. S. Kim
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Phase Change ◽  
Change Process ◽  
Energy Recovery ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Transfer Rates ◽  
Release Capacity ◽  
Temperature Swing

The main barriers affecting the performance of phase change materials (PCM) wallboard system during energy recovery mode are identified as inadequate heat transfer and overall reduction in thermal conductivities. In order to assess the extent of these barriers, two integrated PCM drywall systems (i.e., randomly mixed and laminated PCM systems) have been evaluated numerically. The results showed a great advantage of the laminated PCM-wallboard system over the randomly mixed PCM type in terms of enhanced thermal performance and rapid heat transfer rates under narrow temperature swing. For instance, the maximum instantaneous enhancement in heat flux obtained was between 20% and 50% higher during the phase change process and up to about 18% more heat storage and release capacity. Experimental evaluation is, however, required towards validation and development of the laminated system.

Thermal Performance of a Heat Storage Module Using Calcium Chloride Hexahydrate

1984 ◽  
Vol 106 (1) ◽  
pp. 106-111 ◽  
Author(s):  
D. Dietz
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Phase Change ◽  
Calcium Chloride ◽  
Thermal Performance ◽  
Heat Storage ◽  
Heat Transfer Area ◽  
Transfer Rates ◽  
Chloride Hexahydrate ◽  
Change Material

The thermal performance of an air-heated/cooled, phase-change, heat stoage module was tested and evaluated. The module (rated at 38.7 kWh) consist of 130 vertically oriented tubes filled with 729 kg (1607 lb) of calcium chloride hexahydrate and enclosed in a rectangular box. Heat transfer rates measured during charging and discharging decreased with time as a result of decreasing effective heat transfer area and increasing thermal resistance of the phase-change material. These two dominant effects are included in a proposed mathematical model that predicted the experimental data.

Latent Heat Storage: Container Geometry, Enhancement Techniques, and Applications—A Review

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
S. Arunachalam
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Latent Heat ◽  
Thermal Energy ◽  
Heat Exchangers ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Low Thermal Conductivity

Energy storage helps in waste management, environmental protection, saving of fossil fuels, cost effectiveness, and sustainable growth. Phase change material (PCM) is a substance which undergoes simultaneous melting and solidification at certain temperature and pressure and can thereby absorb and release thermal energy. Phase change materials are also called thermal batteries which have the ability to store large amount of heat at fixed temperature. Effective integration of the latent heat thermal energy storage system with solar thermal collectors depends on heat storage materials and heat exchangers. The practical limitation of the latent heat thermal energy system for successful implementation in various applications is mainly from its low thermal conductivity. Low thermal conductivity leads to low heat transfer coefficient, and thereby, the phase change process is prolonged which signifies the requirement of heat transfer enhancement techniques. Typically, for salt hydrates and organic PCMs, the thermal conductivity range varies between 0.4–0.7 W/m K and 0.15–0.3 W/m K which increases the thermal resistance within phase change materials during operation, seriously affecting efficiency and thermal response. This paper reviews the different geometry of commercial heat exchangers that can be used to address the problem of low thermal conductivity, like use of fins, additives with high thermal conductivity materials like metal strips, microencapsulated PCM, composite PCM, porous metals, porous metal foam matrix, carbon nanofibers and nanotubes, etc. Finally, different solar thermal applications and potential PCMs for low-temperature thermal energy storage were also discussed.

The Investigation of Phase Change Emulsion (PCE): Fabrication, Thermal Conductivity and Utilization of Nanoparticles

2013 ◽  
Vol 860-863 ◽  
pp. 862-866 ◽  
Author(s):  
Yi Fei Zheng ◽  
Zhong Zhu Qiu ◽  
Jie Chen
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Change Material

Phase change materials in the form of emulsion (PCE) is a category of novel phase change fluid used as heat storage and transfer media. It plays an important role in commercially viable applications (energy storage, particularly).The emulsion is made of microparticles of a phase change wax (a kind of paraffin or mixture ) as a phase change material (PCM), mixed paraffin directly with water. This paper presents information on the different PCM emulsions by different researchers. It gives the method of preparation of the PCE, and makes a special effort to investigate the heat transfer phenomena and the method of enhancing the thermal conductivity of the emulsion.

The Experimental Research and Numerical Simulation on Thermal Properties of Molten Salt at Melting Point

2009 ◽  
Author(s):  
Yannan Liang ◽  
Jiemin Zhou ◽  
Ying Yang ◽  
Ye Wu ◽  
Yanyan He
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Phase Change ◽  
Molten Salts ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Phase Interface ◽  
Measuring System ◽  
Solid Liquid

The use of phase-change materials for latent heat storage is a new type of environmentally-friendly energy-saving technologies. Molten salts, one kind of phase-change materials, which have high latent heats, and whose phase transition temperatures match the high temperatures of heat engines, are the most widely used high-temperature phase-change heat storage materials. However, the heat transfer at solid/liquid phase interface belongs to Micro/Nanoscale Heat transfer, lots of the thermal properties of molten salt at melting point is difficult to test. In this investigation, based on the theory that the thermal conductivity can be determined by measuring the speed of the propagation of the solid/liquid phase interface during phase change, a set of system is developed to investigate the thermal conductivity of molten salts at liquid/solid phase transformation point. Meanwhile, mathematical calculation is applied to intuitively simulate the melting and solidifying process in the phase change chamber, by which the error could be analyzed and partly corrected and the result precision could also be increased. And a series of verification experiments have been performed to estimate the precision and the applicability of the measuring system to evaluate the feasibility of the method and measuring system. This research will pave the way to the follow-on research on heat storage at high temperature in industry.

scholarly journals Thermal management and phase change heat transfer characteristics of LiFePO4 batteries by cooling PCM

2021 ◽  
pp. 338-338
Author(s):  
Yaoting Wang ◽  
Tong Meng ◽  
Wenxiao Chu
Keyword(s):  
Heat Transfer ◽  
Energy Consumption ◽  
Phase Change ◽  
Phase Change Materials ◽  
Lithium Iron Phosphate ◽  
Heat Storage ◽  
Expanded Graphite ◽  
Iron Phosphate ◽  
Thermal Safety ◽  
Heat Transfer Characteristics

The cycle life and thermal safety of lithium-iron-phosphate batteries are important factors restricting the popularization of new energy vehicles. The study aims to prevent battery overheating, prolong the cycle life of power batteries and improve their thermal safety by discussing the heat production of lithium-iron-phosphate batteries to solve the problem of temperature rise in the natural convection environment and cut the energy consumption in the liquid cooling system. A numerical simulation and experiment are employed to study the heat production characteristics of LiFePO4 batteries and the heat transfer characteristics of the system, with its Phase Change Materials (PCMs) and Coupling Phase Change Materials of Paraffin and Expanded Graphite), channel liquid, and microchannel PCM coupling cooled to control the temperature of the batteries. The results show that the temperature goes higher with the discharge rate during discharge. Since it has large internal component values, LiFePO4 produces more heat at the beginning and end of discharge. When the battery pack is discharged at 1C and 2C rates, the mass flow rates are 1.8?10?3kg/s and 3.6?10?3kg/s, the temperature can be controlled at most 40?C, and the temperature difference less than 3?C respectively. Paraffin is composed of expanded graphite, and the thermal conductivity of the composite Heat Storage PCMs (Phase Change Heat Storage Materials) is 24 times of that of pure paraffin. Therefore, cooling the active liquid and coupled PCMs can improve the cooling efficiency and has a good effect on solving the problem of temperature rise and energy consumption reduction. The research provides a reference for the thermal energy management of LiFePO4 batteries, providing a method of cooling PCMs (Phase Change Materials) of LiFePO4 batteries.

Thermal properties of nano-graphite-embedded magnesium chloride hexahydrate phase change composites

2017 ◽  
Vol 28 (7) ◽  
pp. 651-660 ◽  
Author(s):  
Apurv Yadav ◽  
Bidyut Barman ◽  
Abhishek Kardam ◽  
S Shankara Narayanan ◽  
Abhishek Verma ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Melting Time ◽  
Chloride Hexahydrate ◽  
Large Heat ◽  
Phase Change Composites ◽  
Change Material

Phase change materials can provide large heat storage density with low volume. But their low thermal conductivity limits their heat transfer capabilities. Since carbonaceous nanoparticles have a good thermal conductivity they can be applied as an additive to phase change materials to increase their heat transfer rate. In this study, nano-graphite is used as an additive and the influences of its various concentrations on the thermal conductivity and melting and freezing rate for the nanoparticle-enhanced phase change materials is experimentally investigated. Experimental results indicates a reduction of 22% in melting time and a reduction of 75% in solidification time of 0.5% nano-graphite-embedded phase change material.

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