Thermal property measurements for ecoroof soils common in the western U.S.

David Sailor, D. Hutchinson, L. Bokovoy

Research output: Contribution to journalArticle

70 Citations (Scopus)

Abstract

To model the impacts of ecoroofs on building envelope heat transfer accurately, thermal property data for ecoroof soils are needed. To address this need we have measured thermal conductivity, specific heat capacity, thermal emissivity, short wave reflectivity (albedo) and density for ecoroof soil samples over a range of moisture states. To represent a wide range of commonly used ecoroof soils we created eight test samples using an aggregate (expanded shale or pumice), sand, and organic matter in varying volumetric composition ratios. The results indicate significant variability in properties as a function both of soil composition and soil wetness. Thermal conductivity ranged from 0.25 to 0.34 W/(m K) for dry samples and 0.31-0.62 W/(m K) for wet samples. Specific heat capacity ranged from 830 to 1123 J/(kg K) for dry samples and 1085-1602 J/(kg K) for wet samples. Albedo was consistently higher for dry samples (0.17-0.40) decreasing substantially (0.04-0.20) as moisture was added. Thermal emissivities were relatively constant at 0.96 ± 0.02 regardless of soil type or moisture status. These results are discussed in the context of their impacts on building energy consumption and the importance of including daily and seasonal property variation within models of the ecoroof energy balance.

Original languageEnglish (US)
Pages (from-to)1246-1251
Number of pages6
JournalEnergy and Buildings
Volume40
Issue number7
DOIs
StatePublished - 2008
Externally publishedYes

Fingerprint

Thermodynamic properties
Soils
Specific heat
Moisture
Thermal conductivity
Shale
Energy balance
Chemical analysis
Abrasives
Biological materials
Sand
Energy utilization
Heat transfer
Hot Temperature

Keywords

  • Building energy
  • Ecoroofs
  • Green roofs
  • Thermal properties

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Civil and Structural Engineering

Cite this

Thermal property measurements for ecoroof soils common in the western U.S. / Sailor, David; Hutchinson, D.; Bokovoy, L.

In: Energy and Buildings, Vol. 40, No. 7, 2008, p. 1246-1251.

Research output: Contribution to journalArticle

Sailor, David ; Hutchinson, D. ; Bokovoy, L. / Thermal property measurements for ecoroof soils common in the western U.S. In: Energy and Buildings. 2008 ; Vol. 40, No. 7. pp. 1246-1251.
@article{e71e9292275948fbb99efa84f9323198,
title = "Thermal property measurements for ecoroof soils common in the western U.S.",
abstract = "To model the impacts of ecoroofs on building envelope heat transfer accurately, thermal property data for ecoroof soils are needed. To address this need we have measured thermal conductivity, specific heat capacity, thermal emissivity, short wave reflectivity (albedo) and density for ecoroof soil samples over a range of moisture states. To represent a wide range of commonly used ecoroof soils we created eight test samples using an aggregate (expanded shale or pumice), sand, and organic matter in varying volumetric composition ratios. The results indicate significant variability in properties as a function both of soil composition and soil wetness. Thermal conductivity ranged from 0.25 to 0.34 W/(m K) for dry samples and 0.31-0.62 W/(m K) for wet samples. Specific heat capacity ranged from 830 to 1123 J/(kg K) for dry samples and 1085-1602 J/(kg K) for wet samples. Albedo was consistently higher for dry samples (0.17-0.40) decreasing substantially (0.04-0.20) as moisture was added. Thermal emissivities were relatively constant at 0.96 ± 0.02 regardless of soil type or moisture status. These results are discussed in the context of their impacts on building energy consumption and the importance of including daily and seasonal property variation within models of the ecoroof energy balance.",
keywords = "Building energy, Ecoroofs, Green roofs, Thermal properties",
author = "David Sailor and D. Hutchinson and L. Bokovoy",
year = "2008",
doi = "10.1016/j.enbuild.2007.11.004",
language = "English (US)",
volume = "40",
pages = "1246--1251",
journal = "Energy and Buildings",
issn = "0378-7788",
publisher = "Elsevier BV",
number = "7",

}

TY - JOUR

T1 - Thermal property measurements for ecoroof soils common in the western U.S.

AU - Sailor, David

AU - Hutchinson, D.

AU - Bokovoy, L.

PY - 2008

Y1 - 2008

N2 - To model the impacts of ecoroofs on building envelope heat transfer accurately, thermal property data for ecoroof soils are needed. To address this need we have measured thermal conductivity, specific heat capacity, thermal emissivity, short wave reflectivity (albedo) and density for ecoroof soil samples over a range of moisture states. To represent a wide range of commonly used ecoroof soils we created eight test samples using an aggregate (expanded shale or pumice), sand, and organic matter in varying volumetric composition ratios. The results indicate significant variability in properties as a function both of soil composition and soil wetness. Thermal conductivity ranged from 0.25 to 0.34 W/(m K) for dry samples and 0.31-0.62 W/(m K) for wet samples. Specific heat capacity ranged from 830 to 1123 J/(kg K) for dry samples and 1085-1602 J/(kg K) for wet samples. Albedo was consistently higher for dry samples (0.17-0.40) decreasing substantially (0.04-0.20) as moisture was added. Thermal emissivities were relatively constant at 0.96 ± 0.02 regardless of soil type or moisture status. These results are discussed in the context of their impacts on building energy consumption and the importance of including daily and seasonal property variation within models of the ecoroof energy balance.

AB - To model the impacts of ecoroofs on building envelope heat transfer accurately, thermal property data for ecoroof soils are needed. To address this need we have measured thermal conductivity, specific heat capacity, thermal emissivity, short wave reflectivity (albedo) and density for ecoroof soil samples over a range of moisture states. To represent a wide range of commonly used ecoroof soils we created eight test samples using an aggregate (expanded shale or pumice), sand, and organic matter in varying volumetric composition ratios. The results indicate significant variability in properties as a function both of soil composition and soil wetness. Thermal conductivity ranged from 0.25 to 0.34 W/(m K) for dry samples and 0.31-0.62 W/(m K) for wet samples. Specific heat capacity ranged from 830 to 1123 J/(kg K) for dry samples and 1085-1602 J/(kg K) for wet samples. Albedo was consistently higher for dry samples (0.17-0.40) decreasing substantially (0.04-0.20) as moisture was added. Thermal emissivities were relatively constant at 0.96 ± 0.02 regardless of soil type or moisture status. These results are discussed in the context of their impacts on building energy consumption and the importance of including daily and seasonal property variation within models of the ecoroof energy balance.

KW - Building energy

KW - Ecoroofs

KW - Green roofs

KW - Thermal properties

UR - http://www.scopus.com/inward/record.url?scp=41749120556&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=41749120556&partnerID=8YFLogxK

U2 - 10.1016/j.enbuild.2007.11.004

DO - 10.1016/j.enbuild.2007.11.004

M3 - Article

VL - 40

SP - 1246

EP - 1251

JO - Energy and Buildings

JF - Energy and Buildings

SN - 0378-7788

IS - 7

ER -