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Title: Thermal charging study of compressed expanded natural graphite/phase change material composites

Abstract

The thermal charging performance of paraffin wax combined with compressed expanded natural graphite foam was studied for different graphite bulk densities. Constant heat fluxes between 0.39 W/cm 2 and 1.55 W/cm 2 were applied, as well as a constant boundary temperature of 60 °C. Thermal charging experiments indicate that, in the design of thermal batteries, thermal conductivity of the composite alone is an insufficient metric to determine the influence of the graphite foam on the thermal energy storage. By dividing the latent heat of the composite by the time to end of melt for each applied boundary condition, the energy storage performance was calculated to show the effects of composite thermal conductivity, graphite bulk density, and latent heat capacity. For the experimental volume, the addition of graphite beyond a graphite bulk density of 100 kg/m 3 showed limited benefit on the energy storage performance due to the decrease in latent heat storage capacity. These experimental results are used to validate a numerical model to predict the time to melt and for future use in the design of heat exchangers with graphite-foam based phase change material composites. As a result, size scale effects are explored parametrically with the validated model.

Authors:
ORCiD logo [1];  [2];  [1]
  1. Georgia Inst. of Technology, Atlanta, GA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Building Technologies Research and Integration Center (BTRIC)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1324191
Alternate Identifier(s):
OSTI ID: 1396799
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Carbon
Additional Journal Information:
Journal Volume: 109; Journal Issue: C; Journal ID: ISSN 0008-6223
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Mallow, Anne, Abdelaziz, Omar, and Graham, Jr., Samuel. Thermal charging study of compressed expanded natural graphite/phase change material composites. United States: N. p., 2016. Web. doi:10.1016/j.carbon.2016.08.030.
Mallow, Anne, Abdelaziz, Omar, & Graham, Jr., Samuel. Thermal charging study of compressed expanded natural graphite/phase change material composites. United States. doi:10.1016/j.carbon.2016.08.030.
Mallow, Anne, Abdelaziz, Omar, and Graham, Jr., Samuel. Fri . "Thermal charging study of compressed expanded natural graphite/phase change material composites". United States. doi:10.1016/j.carbon.2016.08.030. https://www.osti.gov/servlets/purl/1324191.
@article{osti_1324191,
title = {Thermal charging study of compressed expanded natural graphite/phase change material composites},
author = {Mallow, Anne and Abdelaziz, Omar and Graham, Jr., Samuel},
abstractNote = {The thermal charging performance of paraffin wax combined with compressed expanded natural graphite foam was studied for different graphite bulk densities. Constant heat fluxes between 0.39 W/cm2 and 1.55 W/cm2 were applied, as well as a constant boundary temperature of 60 °C. Thermal charging experiments indicate that, in the design of thermal batteries, thermal conductivity of the composite alone is an insufficient metric to determine the influence of the graphite foam on the thermal energy storage. By dividing the latent heat of the composite by the time to end of melt for each applied boundary condition, the energy storage performance was calculated to show the effects of composite thermal conductivity, graphite bulk density, and latent heat capacity. For the experimental volume, the addition of graphite beyond a graphite bulk density of 100 kg/m3 showed limited benefit on the energy storage performance due to the decrease in latent heat storage capacity. These experimental results are used to validate a numerical model to predict the time to melt and for future use in the design of heat exchangers with graphite-foam based phase change material composites. As a result, size scale effects are explored parametrically with the validated model.},
doi = {10.1016/j.carbon.2016.08.030},
journal = {Carbon},
number = C,
volume = 109,
place = {United States},
year = {Fri Aug 12 00:00:00 EDT 2016},
month = {Fri Aug 12 00:00:00 EDT 2016}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 4 works
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