KD2 Pro Thermal Properties Instrument
The KD2 Pro is a fully portable field and lab thermal properties analyzer developed out of 30+ years of research experience on heat and mass transfer in soils and other porous materials. Tested against known standards, the KD2 Pro uses the transient line heat source method to measure thermal conductivity, resistivity, diffusivity, and specific heat.
Accurate
The compact KD2 Pro controller is much more than a simple readout for time and temperature. A proprietary algorithm fits time and temperature data with exponential integral functions using a nonlinear least squares method. This fully mathematical solution delivers thermal conductivity/resistivity to within ±10%.
Correct
The KD2 Pro corrects for temperature drift. Temperature changes of a thousandth of a degree per second—the sun warming the soil, or someone walking into the lab— destroy the accuracy of thermal properties calculations. Unlike other thermal needle systems, the KD2 Pro corrects for linear temperature drift that cause erroneous readings.
Complies with ASTM, and IEEE Standards
For more information, see this application note.
Specifications
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ACCURACY
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± 5 to ± 10% Thermal Conductivity/Resistivity
± 10% Specific Heat
± 10% Thermal Diffusivity
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MEASUREMENT SPEED
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1, 2, 5, & 10 min. read times depending on measurement type (see user’s manual for more information).
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DATA STORAGE
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4,095 readings, flash memory
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COMPLIANCE TO STANDARDS
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ASTM Standard D5334-08 and IEEE Standard 442-1981
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OPERATING ENVIRONMENT OF SENSORS
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-50 °C to 150 °C
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BATTERY SOURCE
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4 AA
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AUTO-READ MODE
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Users can collect unattended data at user-defined intervals in the auto-read mode
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TYPE
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Ultra low-power 16-bit microcontroller w/ 24-bit A/D converter
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DISPLAY
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Liquid Crystal Display (LCD) 7.5 cm x 4 cm
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CASE DIMENSIONS
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15.5 cm x 9.5 cm x 3.5 cm
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INCLUDED ACCESSORIES
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KS-1 Thermal Conductivity/Resistivity sensor (for liquids)
TR-1 Thermal Conductivity/Resistivity sensor (for solids)
SH-1 Dual-Needle Thermal Diffusivity and Specfic Heat sensor (for solids)
User’s manual
Pelican carrying case
Readout stand
Performance verification standards
Thermal grease
Drill bit for drilling pilot holes in materials
Concrete pilot pin
KD2 Pro download utility
RS232 cable
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CALIBRATION
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Each KD2 Pro comes factory calibrated and includes performance verification standards
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RANGE OF MEASUREMENTS
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K: 0.02 to 4 Wm-1 C-1
D: 0.1 to 1.0 mm2s-1
R: 0.25 to 50mC W-1
C: 0.5 to 4 MJ m-3 C-1
* Accuracy and measurement range vary with sensor type. See Comparisons.
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COMPARISONS
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SENSOR
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TR-1
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RK-1
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KS-1
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SH-1
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MEASUREMENT
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Read time- 5 Minutes
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Read time- 10 Minutes
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Read time- 60 Seconds
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Read time- 2 Minutes
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ACCURACY
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(Conductivity): ±10% from 0.2 – 4 W/(m· K)
±0.02 W/(m· K) from 0.01 – 0.2 W/(m· K)
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(Conductivity): ±10% from 0.2 – 6 W/(m· K)
±0.02 W/(m· K) from 0.1 – 0.2 W/(m· K)
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(Conductivity): ±5% from 0.2 – 2 W/(m· K)
±0.01 W/(m· K) from 0.02 – 0.2 W/(m· K)
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(Conductivity) ±10% from 0.2 – 2 W/(m· K)
±0.01 W/(m· K) from 0.02 – 0.2 W/(m· K)
(Diffusivity) ±10% at conductivities above 0.1 W/(m· K)
(Volumetric Specific Heat) ±10% at conductivities above 0.1 W/(m· K)
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RANGES
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K: 0.1 to 4 W/(m·K)
R: 25 to 1000 °C·cm/W
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K: 0.1 to 6 W/(m·K)
R: 17 to 1000 °C cm/W
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K: 0.02 to 2 W/(m·K)
R: 50 to 5000 °C cm/W
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K: 0.02 to 2.00 W /(m· K)
R: 50 to 5000 °C·cm/W
0.1 to 1 mm2/s (diffusivity)
0.5 to 4 mJ/(m3K) (volumetric specific heat
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ENVIRONMENT
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–50 to 150 °C
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–50 to 150 °C
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–50 to 150 °C
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–50 to 150 °C
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DIMENSIONS
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10 cm length
2.4 mm diameter
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6 cm length
3.9 mm diameter
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6 cm length
1.27 mm diameter
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30 mm length
1.30 mm diameter
2 needles, 6 mm spacing
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SAMPLE SIZE
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Sample size is dependent on the thermal properties of the material being tested. In general a 2cm radius of sample material around the needle(s) is sufficient for samples with thermal conductivities around 0.5 W/mK. Samples with lower conductivity (i.e. insulation) can be tested with a smaller sample size. Samples with a higher conductivity (i.e. granite) will require a larger sample to avoid boundary effects.
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KD2 Pro Sensor Compatibility
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SAMPLE MATERIAL
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TR-1
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RK-1
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KS-1
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SH-1
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LOW VISCOSITY LIQUIDS (E.G. WATER)
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No
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No
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Best1
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No
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HIGH VISCOSITY LIQUIDS (E.G. GLYCEROL, OIL)
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Ok
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No
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Best
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No
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INSULATION AND INSULATING MATERIALS
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No
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No
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Best5
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No
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MOIST SOIL
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Best
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Ok
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No
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Ok
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DRY SOIL, POWDERS, GRANULAR MATERIALS
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Best2
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Ok
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No
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Ok
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CONCRETE
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Best3
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Best3
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No
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Ok4
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ROCK
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Best3
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Best3
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No
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Ok4
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OTHER SOLIDS
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Best3
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Ok
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No
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Ok
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VOLUMETRIC SPECIFIC HEAT
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No
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No
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No
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Best
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THERMAL DIFFUSIVITY
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No
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No
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No
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Best
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1 In low viscosity liquids, the read time should be set to the minimum allowed 1 minute to avoid free convection.
2 In dry granular materials where contact resistance can be significant, extending the read time to the maximum allowed 10 minutes will produce the most accurate results.
3 In solid materials where a pilot hole has been drilled and contact resistance can be significant, using thermal grease and extending the read time to the maximum allowed 10 minutes will produce the most accurate results.
4 The SH-1 sensor will take accurate measurements in rock and cured concrete, but it is very difficult to drill small diameter, parallel holes in these materials to accommodate the SH-1 needles.
5 The KS-1 needle in default mode (Low Power, 1 min read time). Heater temperatures with the other probes are too high for insulation measurements.
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