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Specific Heat

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Small and versatile, ideal for many applications

Versatile and inexpensive Dual Needle Heat Pulse Specific Heat Sensor for use in many research applications.

The East 30 Sensors Specific Heat Sensor uses DNHP technology to take accurate measurements of Specific Heat in many situations including:

 

Soil Water Content monitoring

Specific Heat measurements

Laboratory and Field applications

Thermal Diffusivity and Conductivity Measurements

The Specific Heat sensor is designed to be simple and rugged for use in many environments. This sensor uses the Dual Needle Heat Pulse method to make reliable and repeatable measurements in almost all applications. One needle contains a heating element, and the other a precision Thermistor for highly precise temperature measurements.

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Specifications

 Accuracy: ± 5%

Dimensions:

  • Head is 35mm x 10mm

  • Needles 30mm x 1.27mm in diameter

Temperature Sensors:

  • 10K Precision Thermistor

Material:

  • Epoxy and Delrin head

  • Stainless Steel needles

Cable length:

  • 2m standard (additional cable available)

Theory

The Specific Heat Sensor consists of a pair of 30mm-long stainless steel needles, spaced 6mm apart. It is a Dual Needle Heat Pulse sensor (DNHP). One needle contains an Evanohm heater, and the other contains a Precision 10K Thermistor. After the sensor needles are inserted into the sample, a current is applied to the heater for 8 seconds. The temperature rise of the thermistor is then monitored. The specific heat of the material is inversely proportional to the height of the sensed temperature rise, and the thermal diffusivity of the material is related to the time taken for the pulse peak to pass the temperature sensor. The thermal conductivity can then be computed as the product of the thermal diffusivity and the specific heat. 

Publications

 

Bristow, K.L., R.D. White, and R. Horton, 1994. Measurement of Soil Thermal Properties with a Dual-Probe Heat Pulse Technique. Soil Sci. Soc. Am. J. 55:291-293

Bristow, K.L., J.R. Bilskie, G.J. Kluitenberg, and R. Horton, 1995. Comparison of Techniques for Extracting Soil Thermal Properties from Dual Probe Heat Pulse Data. Soil Sci. Am. J. 1:160

Campbell, G.S., C. Calissendorff, and J.H. Williams, 1991. Probe for Measuring Soil Specific Heat Doing a Heat-Pulse Method. Soil Sci. Soc. Am. J. 55:291-293

Kluitenberg, G.J., J.M. Ham, and K.L. Bristow, 1993. Error Analysis of the Heat Pulse Method for Measuring Soil Volumetric Heat Capacity. Soil Sci. Soc. Am. J. 57:1444-1451

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