H40.0.01.6C-09
Operating Manual GMH 3330
Page 9 of 16
6
Measurements Using Combination Measuring Sensor TFS0100
The TFS0100 has been especially designed to carry out measurements of ambient temperature. All
TFS0100-probes are interchangeable without recalibration being required. The scope of supply includes
one sensor to measure relative atmospheric humidity and another one to measure the ambient tempera-
ture T1.
rel. humidity r.H. [%]
relative humidity measured in the tip of the probe. Resolution 0.1%
Ambient temperature T1
temperature measured in the tip of the probe. Resolution 0.1°C or 0.1°F.
Other values on display will be calculated by the measuring device (acc. to Mollier diagram):
Dew point temperature Td
Cold air cannot absorb as much steam as warm air. This means that the
relative
humidity increases as
the temperature decreases. If 100% have been reached, the air is saturated with steam; another de-
crease in temperature results in part of the steam condensing to water, becoming visible as fog or precipi-
tation (dew).
The dew point temperature indicates at which temperature a 100% saturation would be reached and as of
when "dew" can be expected.
Enthalpy h [kJ/kg]
Enthalpy refers to the energy content of air. This value always refers to dry air at 0° C. I.e. the energy con-
tent of air with a relative humidity of 0% and 0°C is 0kJ/kg. The warmer the air the higher the relative hu-
midity, the higher the energy content. Therefore, more energy is required to heat up humid air than dry air.
All humidity and temperature values calculated from the measuring values refer to a standard
atmospheric pressure of 1013 mbar. For measuring atmospheric air, the deviations do not
have to be taken into account.
When taking measurements in pressure vessels or under similar conditions, the values have to
be corrected in accordance with a suitable correction table.
Additional Measurements with NiCr-Ni-Surface Probe at T2:
Surface temperature T2
The second temperature channel can amongst other things be used to take measurements of surface
temperatures.
Dew point distance Td
This measurement refers to measurements of T1, T2 and relative atmospheric humidity.
The combination sensor is used to measure the ambient air, whose condition is used to calculate the dew
point Td. The surface sensor is used to measure surfaces within this ambient air, with Td stating the
temperature difference between those measurements and the dew point.
Example: measuring the ambient temperature results in a Td of 5°C. As long as the surface-temperature
(T2) of a window exceeds 5°C ( Td > 0°C) the surface won´t sweat! When T2 falls below 5°C, ( Td <
0°C) it will sweat.
Other examples for application: detection of 'humid corners', monitoring of heat exchangers, weather fore-
cast etc..
