User manual

Hukseflux Thermal Sensors
HFP01SC Manual v0811 page 20/33
3 Specifications of HFP01SC
HFP01SC self-calibrating heat flux sensor is intended to be used
for determining the heat flux in soil. It is normally used in
combination with a suitable measurement and control system,
including power supply and relay to activate the self calibration
process.
HFP01SC GENERAL SPECIFICATIONS
Specified
measurements
Heat flux in W/m
2
perpendicular to the
sensor surface
Installation See the product manual for
recommendations.
Temperature range -30 to +70 degrees C
Recommended number
of sensors
Meteorological: two for each
measurement station.
CE requirements HFP01SC complies with CE directives
Required depth of
insertion
The medium must be all around
HFP01SC in good thermal contact. The
sensor must be below the surface for at
least 40 mm, typically 50 mm
HFP01SC MEASUREMENT SPECIFICATIONS
Expected accuracy +/- 3% (heat flux measurements)
Overall uncertainty
statement according to
ISO
estimated to be within +5 /- 5%, based
on a standard uncertainty multiplied by
a coverage factor of k = 2, providing a
level of confidence of 95%.
This is a statement according to ISO,
and is according to the manufacturer
too pessimistic.
Thermal conductivity
dependence E
λ
-0.07 % m.K/W (nominal value)
compensated during self-calibration
Temperature
dependence TD
< 0.1%/ °C
compensated during self-calibration
HFP01SC SENSOR SPECIFICATIONS
E
sen
(nominal) 50 µV/ W. m
-2
(exact value on
calibration certificate)
λ
cal
= 0, T
cal
=20 °C
E
sen
is adapted during self-calibration
Sensor thermal
conductivity
0.8 W/mK
Sensor thermal
resistance R
th
< 6.25 10
-3
Km
2
/W
Table 3.1 List of HFP01SC specifications. (continued on the next
page)