We’ve added a new self-calibrating heat flux sensor to our product line. The model HFP01SC is manufactured by Hukseflux of The Netherlands and has been used successfully for the last couple of years by our UK office.
Every two hours under datalogger control, power is applied to an embedded film heater and the resulting heat flux is measured. This process corrects for error caused by differences in the thermal conductivities of the sensor and the surrounding medium, contact resistance, and sensor temperature dependence.
Two differential or single-ended analog input channels are required to measure the HFP01SC. The first is used to measure the sensor output. The second measures the amount of power applied to the film heater during self-calibration. A power control circuit is built into the pigtail end of the HFP01SC signal cable.
The self-calibration takes eight minutes. For the first three minutes, about 14 mW of power is applied to the film heater. For the remaining five minutes, the sensor is allowed to reach equilibrium with the surrounding medium.
The HFP01SC can be used to measure heat flux in many applications. A measure of soil heat flux is required for Bowen ratio determinations of sensible and latent heat flux or for examining energy balance closure in eddy covariance flux measurements.