HFP01SC

Self-Calibrating Heat Flux Sensor

HFP01SC self-calibrating heat flux sensor™ is a heat flux sensor for use in the soil. It offers the best available accuracy and quality assurance of the measurement. The on-line self-test verifies the stable performance and good thermal contact of sensors that are buried and cannot be visually inspected and taken to the laboratory for recalibration. The self-test also includes self-calibration which compensates for measurement errors caused by the thermal conductivity of the surrounding soil (which varies with soil moisture content), for sensor non-stability and for temperature dependence.

  • Low thermal resistance
  • Large guard area (required by the ISO 9869 standard)
  • Low electrical resistance (low pickup of electrical noise)
  • High sensitivity (good signal to noise ratio in low-flux environments)
  • Robustness, including a strong cable (essential for permanently installed sensors)
  • IP protection class: IP67 (essential for outdoor application)
  • Incorporated film heater for self-testing

Description

HFP01SC measures soil heat flux in W/m²
HFP01SC measures soil heat flux in W/m². It is used when the highest level of quality assurance and a high measurement accuracy are requir• ed. In essence, HFP01SC is a combination of a heat flux sensor and a film heater. The heat flux sensor output is a voltage signal that is proportional heat flux through the sensor. At a regular interval the film heater is activated to perform a self-test (see figure 4). The self-test results in a verification of sensor contact to the soil and in a new sensitivity that is valid for the circumstances at that moment. The latter is called self-calibration. Implicitly also cable connection, data acquisition and data processing are tested. The result is a much improved accuracy & quality assurance of the measurement relative to measurements with conventional sensors such as model HFP01.

Unique features and benefits
• Low thermal resistance
• Large guard area (required by the ISO 9869 standard)
• Low electrical resistance (low pickup of electrical noise)
• High sensitivity (good signal to noise ratio in low-flux environments)
• Robustness, including a strong cable (essential for permanently installed sensors)
• IP protection class: IP67 (essential for outdoor application)
• Incorporated film heater for self-testing

Suggested Use
High-accuracy scientific measurement of soil heat flux, with a high level of data quality assurance

Areas of Application
Building physics / insulation, thermal comfort and energy budget measurement
Meteorology / surface energy flux measurement
Scientific research / heat and heat transfer measurement

Specifications

Measurand

heat flux

Measurement range

-2000 to +2000 W/m²

Sensitivity (nominal)

60 x 10⁻⁶ V/(W/m)²

On-line functionality testing

self-test including self-calibration

Sensing area

8 x 10⁻⁴ m²

Sensor thermal resistance

81 x 10⁻⁴ K/(W/m²)

Rated operating temperature range

-30 to +70 °C

IP protection class

IP67

Film heater resistance

100 Ω ± 10 %

Film heater rated power supply

9 to 15 VDC

Interval between self-tests

6hr

Heating interval duration

180s

Power consumption daily average

0.02 W

Standard cable length

2 x 5 m

Options

longer cable length (10, 15, 20, 30, 40 m)

Downloads

Download Product Brochure

Download Product Manual

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