TRSYS20 manual v2301 5/39
Introduction
TRSYS20 is a high-accuracy system for on-site measurement of thermal resistance (R-
value), and thermal transmittance (U-value), of building envelope components. TRSYS20
is mostly used for measurements according to standard practices of ISO 9869 and ASTM
C1155 / C1046. The system is equipped with high-accuracy electronics, two heat flux
sensors of model HFP01 as well as two pairs of matched thermocouples. The two
measurement locations provide redundancy, leading to a high level of confidence in the
measurement result. The high accuracy of the heat flux sensors and temperature
difference measurements ensures that TRSYS20 continues measuring when other
systems no longer perform; in particular at very low temperature differences across the
wall.
HFP01 is a versatile heat flux sensor that, amongst others, has been employed in soil
science applications for studying the heat balance of soils and in building physics
applications for determining the thermal resistances of walls and building envelope
components. For HFP01 specifications, see the HFP01 manual.
Figure 0.1 TRSYS20: the complete measuring system includes 2 HFP01 heat flux sensors
and 2 matched thermocouple pairs, TC, (in total 4 temperature sensors) and the MCU
measurement and control unit.
On-site measurements of thermal resistance, R, are often applied in studies of buildings.
Alternatives are to measure its inverse value, the thermal conductance which is called
the Λ-value, or the thermal transmittance which includes ambient air boundary layer
thermal resistance, the U-value.
The measurements of R are based on simultaneous time averaged measurement of heat
flux Φ and differential temperature, ΔT, (using two temperature sensors, each on a
different side of the wall).
R = ΔT / Φ
The ISO and ASTM standards give detailed directions concerning the measurement
method, sensor installation and data analysis.
