Heat Flow Measurement Error

Heat flow value can be obtained by simply touching the heat flow meter sensor to the substance being tested. However, to obtain a more reliable value, there are several points when operating:

The following may lead to error:

1) sensor attachment
2) wind
3) radiation rate
4) heat conduction λ of the substance being measured
5) heat conduction λ of the backfill in embedded sensors

Heat Flow Measurement Error [sensor installation]

Affixed-type sensors are applied to avoid any air pockets between subject material and sensor. Please use adhesive sheets “HA2-H” or “HA2-L” in affixing the sensors.

Heat Flow Sensor Error [wind]

It is well-known that heat flow can change due to wind, but trouble also occurs due to change in film resistance.

Because the sensor reads oversensitively to extreme changes, it shows fluctuations larger than the actual heat flow change.

Therefore, the average capability is attached to the device. Also, with a steady wind (or average wind speed), the device will display a value that differs with the actual heat flow.

This is a result of the difference between the transfer constant of what is being measured and that of the sensor.

Generally, the indication is larger because the sensor transfer constant is greater.