scholarly journals Experimental Research on the Thermal Performance of Composite PCM Hollow Block Walls and Validation of Phase Transition Heat Transfer Models

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Yuan Zhang ◽  
Sunqi Zhuang ◽  
Qian Wang ◽  
Jiapeng He
Keyword(s):  
Heat Transfer ◽  
Phase Transition ◽  
Thermal Performance ◽  
Heat Transfer Process ◽  
Unsteady State ◽  
Typical Structure ◽  
Hollow Block ◽  
Change Material ◽  
Capacity Method ◽  
Transition Heat

A type of concrete hollow block with typical structure and a common phase change material (PCM) were adopted. The PCM was filled into the hollow blocks by which the multiform composite PCM hollow blocks were made. The temperature-changing hot chamber method was used to test the thermal performance of block walls. The enthalpy method and the effective heat capacity method were used to calculate the heat transfer process. The results of the two methods can both reach the reasonable agreement with the experimental data. The unsteady-state thermal performance of the PCM hollow block walls is markedly higher than that of the wall without PCM. Furthermore, if the temperature of the PCM in the wall does not exceed its phase transition temperature range, the PCM wall can reach high thermal performance.

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.

Numerical Simulation of Melting of Phase Change Material in a Square Cavity with a Heat Source

2016 ◽  
Vol 685 ◽  
pp. 104-108 ◽  
Author(s):  
Nadezhda S. Bondareva ◽  
Mikhail A. Sheremet
Keyword(s):  
Heat Transfer ◽  
Phase Transition ◽  
Heat Source ◽  
Local Heat ◽  
Effect Of Temperature ◽  
Square Cavity ◽  
Flow And Heat Transfer ◽  
The Finite Difference Method ◽  
Change Material ◽  
Melting And Solidification

Melting and solidification problems are important in applications of many industries. In the present work mathematical simulation of natural convection with phase transition inside an enclosure with a local heat source has been carried out. Partial differential equations with corresponding initial and boundary conditions have been solved using the finite difference method. The effect of temperature differences on fluid flow and heat transfer has been discussed.

scholarly journals Experimental Investigation on Thermal Performance of Double-U-tube Heat Exchanger Using CuO/water Nanofluid as Heat Transfer Fluid

2020 ◽  
Vol 165 ◽  
pp. 01022
Author(s):  
Ruiqing Du ◽  
Dandan Jiang ◽  
Yong Wang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Thermal Performance ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Heat Transfer Fluid ◽  
Geothermal Heat ◽  
Tube Heat Exchanger ◽  
Heating And Cooling ◽  
Geothermal Heat Exchanger

By applying the shallow ground energy to supply building heating and cooling, the geothermal heat exchanger systems were considered as an energy-efficient building service system. In this study, the CuO/water nanofluid was employed as circuit fluids of the geothermal heat exchanger system, and the thermal performance of the heat exchanger was investigated. The results showed that the heat transfer process of CuO/water nanofluid became stable earlier than that water. Furthermore, the heat transfer rate of nanofluid was higher than that of water when the heat transfer process plateaued.

Thermal Performance of Microencapsulated Phase Change Material Slurry in a Coil Heat Exchanger

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Min-Suk Kong ◽  
Kun Yu ◽  
Jorge L. Alvarado ◽  
Wilson Terrell
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Phase Change ◽  
Thermal Performance ◽  
Mass Fraction ◽  
Microencapsulated Phase Change Material ◽  
Coil Heat Exchanger ◽  
Change Material ◽  
Coil Heat

An experimental study has been carried out to investigate the convective heat transfer and pressure drop characteristics of microencapsulated phase change material (MPCM) slurry in a coil heat exchanger (CHX). The thermal and fluid properties of the MPCM slurries were determined using a differential scanning calorimeter (DSC) and a rotating drum viscometer, respectively. The overall heat transfer coefficient and pressure drop of slurries at 4.6% and 8.7% mass fractions were measured using an instrumented CHX. A friction factor correlation for MPCM slurry in the CHX has been developed in terms of Dean number and mass fraction of the MPCM. The effects of flow velocity and mass fraction of MPCM slurry on thermal performance have been analyzed by taking into account heat exchanger effectiveness and the performance efficiency coefficient (PEC). The experimental results showed that using MPCM slurry should improve the overall performance of a conventional CHX, even though the MPCM slurries are characterized by having high viscosity.

scholarly journals Visualization Study on Thermo-Hydrodynamic Behaviors of a Flat Two-Phase Thermosyphon

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2295 ◽  
Author(s):  
Chao Wang ◽  
Feng Yao ◽  
Juan Shi ◽  
Liangyu Wu ◽  
Mengchen Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Thermal Performance ◽  
Flow Behavior ◽  
Heat Transfer Process ◽  
Liquid Pool ◽  
Two Phase ◽  
Convective Boiling ◽  
Wick Structure ◽  
Vapor Liquid

The coupled effect of boiling and condensation inside a flat two-phase thermosyphon has a non-negligible influence on the two-phase fluid flow behavior and heat transfer process. Therefore, a flat two-phase thermosyphon with transparent wall was manufactured. Based on this device, a visualization experiment system was developed to study the vapor–liquid two-phase behaviors and thermal performance of the flat two-phase thermosyphon. A cross-shaped wick using copper mesh was embedded into the cavity of two-phase thermosyphon to improve the heat transfer performance. The effects of heat flux density, working medium, and wick structure on the thermal performance are examined and analyzed. The results indicated that a strong liquid disturbance is caused by the bubble motions, leading to the enhancement of both convective boiling and condensation heat transfer. More bubbles are generated as the heat flux increases; therefore, the disturbance of bubble motion on liquid pool and condensation film becomes stronger, resulting in better thermal performance of the flat two-phase thermosyphon. The addition of the wick inside the cavity effectively reduces the temperature oscillation of the evaporator wall. In addition, the wick structure provides backflow paths for the condensate owing to the effect of capillary force and enhances the vapor–liquid phase change heat transfer, resulting in the improvement of thermal performance for the flat two-phase thermosyphon.

Analysis of Electric Performance and Optimization of Trough Concentrating Solar Thermoelectric Cogeneration System

2013 ◽  
Vol 368-370 ◽  
pp. 1209-1213
Author(s):  
Zhi Ping Chen ◽  
Ming Li ◽  
Xu Ji ◽  
Xi Luo
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Performance Optimization ◽  
Heat Transfer Process ◽  
Working Fluid ◽  
Transfer Model ◽  
Experimental Basis ◽  
Parabolic Trough ◽  
One Dimensional ◽  
Cogeneration System

This study introduced the basic situation of the parabolic trough concentrating solar cogeneration system, and set a one-dimensional steady-state mathematical heat transfer model based on the experimental devices, at the same time clarified influencing factors of the major heat transfer process and thermal performance of the system. The article did perspectives theoretical analysis and simulation for the system in different aspects, through using of solar trough concentrator reflecting device, established thermal performance experiments that water as the working fluid flow, provided theoretical and experimental basis for the thermal performance optimization of the system.

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