What is the thermal conductivity of stone?
What is the thermal conductivity of stone?
R-Value for Natural Stone
| Material Type | k-Value (Thermal Conductivity) (W/mK) | R-Value Equivalent (R)3 (Hr • ft2 • ºF / Btu) |
|---|---|---|
| Granite (Barre)2 | 2.79 | 0.052 |
| Limestone (High Value)1 | 1.26 | 0.114 |
| Limestone (Low Value)1 | 1.33 | 0.108 |
| Limestone (Salem)2 | 2.15 | 0.067 |
What is thermal conductivity of shale?
For clastic rocks, the mean thermal conductivities of sandstone, mudstone, and shale are 3.06 ± 0.73, 2.57 ± 0.42, and 2.48 ± 0.33 W/m K, respectively; for carbonate rocks, the mean thermal conductivities of limestone and dolomite are 2.53 ± 0.44 and 3.55 ± 0.71 W/m K, respectively; for gypsum rocks, the mean thermal …
Which rock is thermal insulator?
pumice
Also pumice, a volcanic rock that is full of cavities, is often used as a thermal and acoustic insulator, after being milled and mixed to mortars.
How do you measure the thermal conductivity of a rock?
An apparatus (Transient Divided Bar – TDB) was implemented to determine the thermal conductivity of rocks. TDB consists of a stack of elements, which comprise a rock specimen placed between two copper blocks of cylindrical shape with known thermal capacity, initially kept at room temperature.
What rocks hold heat the best?
Natural stones with high energy density and excellent thermal conductivity are soapstone (by far the best) and marble. These are perhaps the best stones for absorbing large amounts of heat quickly.
What is thermal properties of rocks?
Thermal properties are related to mineral composition, compaction (and in consequence porosity), and anisotropy of the rock. The other important factors in the rock formation are volumetric ratios between the solid, liquid, and gaseous phases and moisture content.
Which rock has the highest thermal conductivity?
Higher thermal conductivity values are for most sedimentary and metamorphic rocks, while very high are typical for felsic igneous rocks. Rocks with high quartz content (e.g. quartzite, sandstone), as well as water-saturated rocks, are the best heat conductors [9].
What is the thermal conductivity of basalt?
Thermal conductivity
| material | at 20 °C | at 200 °C |
|---|---|---|
| basalt | 4.0 | 4.0 |
| dunite | 12.0 | 8.1 |
| marble | 7.3 | 5.2 |
| quartzite | 15.0 | 9.0 |
What is the thermal conductivity of granite?
The thermal conductivities range from 2.9 W/rnK for granites with a high porosity to 3.6 W/rnK for ones with a low porosity under saturated condition. The specific heats of granite range from 0.76 to 0.79 J/gK under dry condition and from 0.80 to 0.85 J/gK under saturated condition.
What holds heat the longest?
Electronics.
Is granite thermally conductive?
The thermal conductivities of the main minerals of granite are in the range of 1.6 to 7.7 W/mK at room temperature (Horai, 1971), which are much larger than that of air which is 0.03 W/mK at room temperature. Therefore an increase of the porosity results in a decrease in the thermal conductivity.
What rocks retain heat the best?
Heat retention Marble and limestone are particularly good at absorbing heat, while granite is particularly good at conducting heat. Basalt and soapstone are particularly good at storing heat and releasing it slowly over a long period of time.