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Enabling better global research outcomes in soil, plant & environmental monitoring.

Hukseflux HFP01SC 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

Suggested use

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

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 required. 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. 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
Measurand: heat flux
Measurement Range: -2000 to +2000 W/m²
Sensitivity (nominal): 60 x10⁻⁶ V/(W/m)²
On-line functionality testing: self-test including self-calibration
Sensing area: 8 x10⁻⁴ m²
Sensor thermal resistance: 81 x10⁻⁴ 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: 6 hr
Heating interval duration: 180 s
Power consumption daily average: 0.02 W
Standard cable length: 2 x 5 m
Options: longer cable length (10, 15, 20, 30, 40 m)