Hukseflux

Thermal Sensors

USER MANUAL TRSYS20
High-accuracy building thermal resistancemeasuring system with two measurement
locations

Copyright by Hukseflux | TRSYS20 manual v2301 | www.hukseflux.com | info@hukseflux.com

Cautionary statements
Cautionary statements are subdivided into four categories: danger, warning, caution andnotice according to the severity of the risk.
DANGER
Failure to comply with a danger statement will lead to death or serious
physical injuries.

WARNING
Failure to comply with a warning statement may lead to risk of death orserious physical injuries.

CAUTION
Failure to comply with a caution statement may lead to risk of minor ormoderate physical injuries.

NOTICE
Failure to comply with a notice may lead to damage to equipment or may
compromise reliable operation of the instrument.

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Contents
Cautionary statements
Contents
List of symbols
Introduction
1
Ordering and checking at delivery
1.1
Ordering TRSYS20
1.2
Included items
2
Instrument principle and theory
2.1
TRSYS20 measuring system
2.2
Theory3
Specifications of TRSYS20
3.1
Specifications of TRSYS20
3.2
Dimensions of TRSYS20
4Preparation of an experiment
4.1
Preparing the equipment
5
TRSYS20 MCU system setup
5.1
Setting up connection
5.2
Setting the clock
5.3
Setting the net frequency filter
5.4
Verifying the programmed HFP01 sensitivity
6
Installation of sensors: HFP01 and TC
6.1
Site selection and installation
7
Performing measurements
7.1
Starting an experiment
7.2
Monitoring measurements
7.3
Retrieving measurement data
8
Data analysis tool
8.1
Importing the data
8.2
Viewing results
9
Uncertainty evaluation
9.1
Heat flux measurements
9.2
Temperature difference
9.3
Thermal resistance
10
Maintenance and trouble shooting
10.1 Recommended maintenance and quality assurance
10.2 Trouble shooting
10.3 Calibration and checks in the field
10.4 Storage
11
Appendices11.1 TRSYS20 data table11.2 EU declaration of conformity

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List of symbols
Quantities

SymbolHeat fluxΦVoltage output
U
Sensitivity
S
TemperatureT
Temperature difference
ΔT
Time constantτ
Thermal resistance, from surface to surface
R
Thermal resistance, from environment to environment RT
Λ-Value, thermal conductanceΛ
Thermal resistance ambient air boundary layer for:indoor layer
Ramb., indoor
outdoor layer
Ramb., outdoor
U-Value, thermal transmittanceU
Timet
Thermal conductivity
λThermal resistivityrAmbient air / wind speedv
Volumetric heat capacity
Cvolumetric
ResistanceR
Heat transfer coefficienthConvection heat transfer coefficienthc
Radiation heat transfer coefficient
hr

Unit
W/m²
V
V/(W/m2)°C°C, Ks
K/(W/m²)
K/(W/m²)
W/(m²·K)
K/(W/m²)
K/(W/m²)
W/(m²·K)s
W/(m∙K)m∙K/W
m/s
J/(m³∙K)Ω
W/(m²·K)
W/(m²·K)
W/(m²·K)

Subscripts
Property of thermopile sensor
Property of ambient air
Property at indoor location
Property at outdoor location

sensorambient
indooroutdoorAcronyms
GUI
MCU
PC
PSU
ISO
ASTM
TC
HFM
HFT

Graphical User Interface
Measurement Control Unit
Personal Computer
Power Supply Unit
International Organization for Standards
American Society for Testing and Materials
Thermocouple
heat flow meter (ISO)heat flow transducer (ASTM)

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Introduction
TRSYS20 is a high-accuracy system for on-site measurement of thermal resistance (Rvalue), 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 themeasurement result. The high accuracy of the heat flux sensors and temperature
difference measurements ensures that TRSYS20 continues measuring when othersystems no longer perform; in particular at very low temperature differences across thewall.
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 adifferent side of the wall).
R = ΔT / Φ
The ISO and ASTM standards give detailed directions concerning the measurement
method, sensor installation and data analysis.
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The TRSYS20 system employs dedicated sensors and electronics. Their high sensitivity
and accuracy ensure that TRSYS20 will still measure under circumstances wherecompeting systems no longer perform reliable measurements; i.e. down to very low heat
fluxes and low temperature differences across the wall. The matched thermocouple pairs
in TRSYS20, measure temperature differences with an uncertainty of better than 0.1 °C
over the entire rated temperature range. TRSYS20 includes 2 x HFP01 heat flux plates.
HFP01 is the world’s most popular sensor for heat flux measurement in studies ofbuildings.
The system generates a measurement file, including time, heat flux, temperature andtemperature difference for the two measurement locations. The measurement is stored in
the MCU and later downloaded to a PC. The user is responsible for data analysis,
calculating the R-value or U-value of the building envelope according to the ISO or ASTM
standards.
Equipped with heavy-duty components, TRSYS20 has proven to be very robust andstable. It survives repeated installation necessary in this application where measuringsystems are typically used at multiple locations.
The measurements and the analyses that have to be performed are not straightforward;
although the measurements are standardised, this always involves a significant elementof expertise and a subjective data interpretation. Hukseflux helps to gain the necessary
experience by offering operator training.
Training vastly improves the level of service to the end user, the efficiency of working
with the equipment and reduces the uncertainty of the end result. Please contact us formore information on training courses in thermal measurement at Hukseflux.

Figure 0.2 TRSYS20 consists of MCU Measurement and Control Unit (3), a 12 VDC
adapter to power the MCU (1), two pairs of matched thermocouples (4) to be placed on
both sides of a wall, and two model HFP01 heat flux plates (5) to be placed on the inside
side of a wall. The MCU measures and stores measurement data. The MCU can be

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connected to a PC (2, not included) via USB or ethernet. Graphical user interface isaccessible through a web browser.
Calibration of TRSYS20 components is traceable to international standards.
HFP01 and MCU are traceable to the international standards for voltage, current andlength, the thermocouples to ITS-90. TRSYS20 undergoes a functional test at the factory.
This conformity assessment includes temperature difference measurement accuracy.

Figure 0.3 TRSYS20 in its carrying case on the left and one HFP01 sensor on the right. 2
HFP01 heat flux sensors and 2 matched thermocouple pairs, TC, (in total 4 temperature
sensors) are included in TRSYS20.

TRSYS20 advantages• Connection via ethernet or USB. The MCU can be connected to a local area network(LAN) via ethernet or directly to a PC via USB.
• Intuitive and easy-to-use graphical user interface. The MCU acts as a server thatprovides a graphical user interface in the form of a webpage. The graphical user interface
is accessible through a web browser. No software installation is required.
• Matched thermocouple pairs. Matched thermocouple pairs have a measurement
uncertainty of better than 0.1 °C over the entire rated temperature range. Their highaccuracy and sensitivity ensure that TRSYS20 will still measure under circumstanceswhere competing systems no longer perform reliable measurements; i.e. down to very
low heat fluxes and low temperature differences across the wall.

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Suggested use
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 / ΦStandards
TRSYS20 is mostly used for measurements according to standard practices of ISO 9869
and ASTM C1155 / C1046. TRSYS20 is suitable for use by ISO certified laboratories.

Figure 0.4 TRSYS20 measuring system with carrying case.

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User interface: MCU as a web server
TRSYS20 is controlled via a PC. The TPSYS20 MCU can be connected to a local area
network via ethernet or directly to a PC via USB. The graphical user interface is available
through a webpage and can be opened in any of the supported web browsers. No
installation of software is required. The graphical user interface allows the user toconfigure measurement parameters, control measurements, view measurement progress
and to view and download measurement results.

Figure 0.5 TPSYS20 graphical user interface, accessible through a web browser.

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1 Ordering and checking at delivery
1.1 Ordering TRSYS20
The standard configuration of TRSYS20 is with 2 x heat flux sensor, one with 10 and one
with 20 m cable, and 2 x matched thermocouple pairs, TC, one pair with 10 m cable andone pair with 20 m cable.

1.2 Included items
Arriving at the customer, the TRSYS20 delivery should include:• 1 x carrying case
• 1 x TRSYS20, consisting ofo a measurement and control unit (MCU)o 2 x HFP01 heat flux plates
o 2 x matched thermocouple pairs• 1 x 12 VDC Power supply unit (PSU), with 4 interchangeable AC plugs• 1 x USB-A to USB-B cable• 1 x product certificate TRSYS20

Figure 1.2.1 Overview of TRSYS20: the system includes 2x HFP01 sensor (4), 2x
matched thermocouple pairs (5), and the MCU (6). The MCU is powered from a 12 VDC
power source (1). Communication with the MCU can be done via an ethernet port (2) ora USB port (3).
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2 Instrument principle and theory
TRSYS20 measuring system consists of multiple heat flux- and temperature sensors thatare used to measure heat fluxes through- and temperature difference across walls orbuilding envelope components. The data can be used to estimate the energy budget ofbuildings and to determine thermal resistance of walls. The data analysis required todetermine thermal resistance, R, thermal conductance, Λ, or thermal transmittance, U,from the data is the responsibility of the user and should be performed according to ISO
and ASTM recommended practices.
This chapter provides a brief introduction into the theory, the relevant standards and the
TRSYS20 operating principle.

Figure 2.1 HFP01 heat flux sensor and TC mounted on a wall.

2.1 TRSYS20 measuring system
2.1.1 HFP01 heat flux sensors
TRSYS20 uses HFP01 heat flux sensors to measure the heat flux through building
envelope components. Heat flux is the amount of heat flowing through a surface per unit
time per unit area and is expressed in SI units of W/m2.
HFP01 heat flux sensor contains a thermopile that generates an output voltage that is
proportional to the temperature difference across the heat flux sensor. From Fourier’s
law it follows that the temperature difference across the heat flux sensor is proportional
to the heat flux through the sensor. Hence output voltage U is proportional is
proportional to the heat flux Φ:

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Φ = U/S
Where S, a constant, is the sensitivity of the heat flux sensor. HFP01 is calibrated at thefactory.
Installation of a heat flux sensor generally perturbs the heat flows. To avoid perturbing
the heat flows, heat flux sensors should have a small thermal resistance while having asufficiently large sensitivity for their application. HFP01 is designed to minimize theperturbation while having a high sensitivity.
For more details on the HFP01 heat flux sensors, the reader is referred to the HFP01
manual.

2.1.2 Matched thermocouple pairs
TRSYS20 uses matched thermocouple pairs to measure temperature differences acrossbuilding envelope components. While the absolute temperature measuring accuracy of
individual thermocouples is low, matched thermocouple pairs can be used to very
accurately measure temperature differences. Proper selection / pairing leads touncertainties better than 0.1 °C over the full rated measurement range.

2.1.3 Measurement and control unit (MCU)
The measurement and control unit (MCU) contains a Campbell Scientific CR1000X
datalogger. The MCU is used to measure the voltage signals from the heat flux sensors
and thermocouples, process the signals, store measurement data and to provide a userinterface.
The MCU uses high resolution AD converters to measure the voltage signals from theheat flux sensors and thermocouples. A net-frequency filter is used to minimize cross talkfrom power lines. The net-frequency filter must be set to net frequency (50 or 60 Hz) of
the region in which the system is used. The MCU measured voltages are then converted
to heat flux, temperature and temperature difference values. It has an on-board
temperature sensor that acts as a cold junction measurement for the thermocouples.
This is called the panel temperature.
MCU contains a clock and memory. 10 minute averages of heat flux, temperature andtemperature differences are stored along with appropriate time stamps. Once ameasurement has been completed, the measurement data can be downloaded from the
MCU.
The MCU provides a user interface that allows the user to view live measurement data as
well as preliminary results. The user interface is accessible via a PC or laptop using a web
browser. To access the user interface the MCU can be connected via USB or ethernet.

2.2 Theory
TRSYS20 is a system for in-situ (or field) measurements of the thermal resistance ofbuilding envelope components as opposed to ex-situ (or laboratory) measurements.

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In-situ thermal resistance evaluations use long-term averages of temperature difference
across- and heat flux through the wall or building envelope component. Using the timeaveraged temperature difference ΔTavg and time-averaged heat flux Φavg the thermal
resistance can be evaluated using the thermal equivalent of Ohm’s law:
R = ΔTavg /Φavg(Formula 2.1.1)

For finite measuring times the evaluation of the thermal resistance is complicated by thefact that walls have a non-zero heat capacity. A wall absorbs and releases heat during aday. Measurement duration should be long enough to allow the R-value to stabilize.
Typical measurement times are on the order of one to two weeks, with a minimum of 3days. The required measurement time ultimately depends on the thermal properties of
the wall or building envelope component as well as the measuring conditions.
There are several applicable standards for in-situ thermal resistance measurements. The
standards provide guidance on how to perform measurements as well as methods forprocessing measurement data and obtaining thermal resistances or similar quantities ofinterest. Specifically, the standards contain methods for determining whether sufficient
data has been collected, as well as corrections to formula 2.1.1 for finite timemeasurements on walls with high thermal resistance and heat capacity. These standards
are discussed in more detail in section 2.2.1. The user is responsible for the data
analysis.

2.2.1 Applicable standards
Table 2.2.1.1 contains a listing of applicable standards. We recommend users topurchase the latest version of the standard.
Table 2.2.1.1 Standards with recommendations for instrument use in building physics.
STANDARDS FOR INSTRUMENT USE FOR BUILDING ENVELOPE THERMAL RESISTANCEMEASUREMENTISO STANDARD
EQUIVALENTASTM STANDARD
ISO 9869 Thermal insulation – Building
ASTM C 1155-95 Standard Practice forelements – In-situ measurement of thermal
Determining Thermal Resistance of Building
resistance and thermal transmittance
Envelope Components from the In Situ Data
ASTM 1046-95 Standard Practice for In Situ
Measurement of Heat Flux and Temperature on
Building Envelope Components

2.2.2 ISO 9869-1:2014: thermal conductance (Λ-value) and transmittance (Uvalue)
ISO 9869-1 makes a distinction between:• thermal resistance R from surface to surface by conduction, in SI units of m2∙K/W,
calculated from heat flux and surface temperature difference Tsurface (or the inverse
value: thermal conductance Λ, in SI units of W/(m2∙K))• thermal resistance RT from environment to environment by convection plus
conduction, calculated from heat flux and ambient air temperature difference Tambient(or the inverse value: thermal transmittance U)
Typically, the wall thermal conductance Λ (or thermal resistance R) is measured using
surface temperatures on the wall:
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Λ = 1/R = Φ/(Tsurface, indoor – Tsurface, outdoor)(Formula 2.2.2.1)

The thermal resistance R of an old insulated wall is of the order of 2.5 K/(W/m2), a
modern insulated wall may attain 6.7 K/(W/m2).
The thermal transmittance U is a measure how effective a material is as an insulator. The
lower the U value, the less heat is lost and the more insulation the material provides. Uvalue includes an ambient air boundary thermal layer at the inside and outside of thewall. When measuring the thermal transmittance:
U = 1/RT = Φ/(Tambient, indoor – Tambient, outdoor)(Formula 2.2.2.2)

The U-value (or alternatively RT ) includes Rambient, indoor and Rambient, outdoor, a thermalboundary layer of air plus radiative transport resistance.
RT = R + Rambient, indoor + Rambient, outdoor(Formula 2.2.2.3)

Formula 2.2.2.4 shows a typical assumption for non-ventilated walls for 2 surfaces:
Rambient = Rambient, indoor + Rambient, outdoor = 0.25 K/(W/m2)(Formula 2.2.2.4)

The convective transport of heat from the wall to the ambient air, Φ, is a function of theheat transfer coefficient, hc, and the temperature difference between ambient air andsensor.
Φ = hc ∙ ( Tambient – Tobject ) = ( Tambient – Tobject )/Rambient(Formula 2.2.2.5)

In buildings under indoor conditions we expect wind speeds of < 1 m/s. Indoor
environments such as office spaces will typically have wind speeds < 0.5 m/s. Outdoors,
wind speeds may reach 15 m/s under normal conditions, and up to 60 m/s in case ofheavy storm.
An approximation of the heat transfer coefficient at a single surface at moderate ambient
air speeds, v, and taking 5 W/(m2·K) for the radiative transfer coefficient, is given by:
h = hr + hc = 5 W/(m2·K) + 4 J/(m3·K) ∙ v(Formula 2.2.2.6)

According to ISO 9869, A.3.1, a common value for the heat transfer coefficient by
convection, hc, for a single surface is 3.0 W/(m2·K); in the equation above this would
represent a wind speed of 0.75 m/s. The total heat transfer coefficient h for one surface
then is 8 W/(m2·K). For two surfaces Rambient then becomes 0.25 K/(W/m2) according toformula 2.2.2.4.
The radiative heat transfer coefficient of 5 W/(m2·K) follows from the Stefan–Boltzmann
law, linearised around 20 °C.
In this standard the heat flux sensor name is heat flowmeter (HFM). Installation is
described in ISO 9869 paragraph 6.1.2. The user should verify the representativeness of
the area with a thermal camera. The installation should not be in the vicinity of potential
sources of error such as thermal bridges, cracks, heating or cooling devices and fans.
Sensors should not be exposed to rain, snow, and direct solar radiation. The standard
recommends use of thermal paste. Hukseflux discourages the use of thermal paste
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because it tends to dry out. Silicone glue and double sided tape are more reliable. The
standard recommends the use of a passive guard ring. Annex D.3.2 states that “thewidth of the guard ring should be at least 5 times the thickness of the heat flux meter”.
HFP01 is equipped with a guard ring fulfilling the requirement of the standard. The ISO
9869-1 standard provides three methods for obtaining the thermal resistance frommeasurement data:
1. The average method (ISO 9869-1, paragraph 7.1).
2. The average method with a correction for storage effects (ISO 9869-1,
paragraph 7.2).
3. The dynamic method (ISO 9869-1, Annex B).
For the average method, when measuring the thermal resistance of a building element,
the duration of the test according to ISO 9869-1 should be at least 72 h (ISO 9869-1
paragraph 7.1). In some cases, only night time data may be included in the analysis. At
the end of a test the obtained R – value should not deviate by more than ± 5 % from thevalue obtained 24 h before, i.e. the measurement should converge. Furthermore, thethermal resistance value obtained by analysing the initial 2/3 of the test data should notdeviate from value obtained by analysing the final 2/3 of the test data by more than
± 5 %, i.e. the measurement should be consistent. Whenever the change in heat storedby the wall is more than 5 % of the heat flow through the wall during the test period, thefirst method is insufficient and either the second or the third method listed above should
be used.
Chapters 7 and 8 of the ISO standard describe corrections for storage effects (changes inaverage wall temperature), added thermal resistance by the heat flux sensor, which wecall the resistance error, and errors caused by the finite dimensions of the sensor.
ISO 9869 chapter 9 shows examples of uncertainty evaluation, arriving at typicaluncertainties of the order of ± 20 % of on-site measurements of thermal resistances.
Sensors for measurement of temperature difference should be calibrated to an accuracyof ± 0.1 °C, reference paragraph 9.2 of this manual.

2.2.3 ASTM C 1155 and ASTM 1046: thermal resistance R
ASTM C 1155 and ASTM 1046 focus on the measurement of thermal resistance R (fromsurface to surface) only. This is the R-value of formula 2.2.2.1.ASTM 1155 defines a Heat
Flow Sensor or Heat Flux Transducer (HFT). Paragraph 5.8 of the standard specifies thatduring the test the indoor temperature changes less than 3 °C, and specifies that thedensity of the construction material is < 440 kg/m3. Areas with a high lateral heat flux
should be avoided. Time constants should be estimated according to ASTM 1046. The
duration of the test is at least 24 h, and a convergence test may be used to determine
total required timespan.
ASTM 1046 offers good practices for installation and site selection.

2.2.4 Measurements on glass windows

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TRSYS20 and HFP01 may be mounted on glass windows, however special care must be
taken when interpreting data from measurements on glass. When measuring glass
windows please observe the following:• During daytime, the window material typically transmits solar radiation, while the
HFP01 heat flux sensors absorb this radiation. During daytime the measurement is not
representative of the heat flux through the window. It is recommended to use nighttime data only.
• For windows with low R-value (high Λ-value), especially single-layer glass windows,
the thermal resistance of HFP01 itself may be non-negligible. The user should review
their case and may correct for the resistance error.

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3 Specifications of TRSYS20
3.1 Specifications of TRSYS20TRSYS20 is a system used for on-site measurement of thermal resistance, R, thermal
conductance, the Λ-value, and thermal transmittance, the U-value, of building envelope
components. TRSYS20 is used for measurements according to standard practices of ISO
9869 and ASTM C1155 / C1046. The system is equipped with MCU electronics, two heat
flux sensors of model HFP01 as well as two pairs of matched thermocouples. The sensors
are used to measure at two locations. Data review and calculation of the thermal
resistance from heat flux and temperature difference is the responsibility of the user.
Table 3.1.1 Specifications of TRSYS20 (continued on next page).
TRSYS20 SPECIFICATIONS
Description
Measurand
Measurand in SI units
Measurand
Measurand in SI units
Measurand
Measurand in SI units
Use
Required data analysis to determine
thermal resistance, R, thermal
conductance, the Λ-value, and thermaltransmittance, the U-value
Minimum measurement duration
Standards governing use of themeasuring system

high-accuracy building thermal resistance measuringsystem with two measurement locations
heat flux (2 x)heat flux density in W/m²
temperature (2 x)temperature in °C
temperature difference (2 x)temperature difference in °C
to be performed by the user according to ISO andASTM recommended practices> 3 days•
ISO 9869 Thermal insulation – Building elements– In-situ measurement of thermal resistance andthermal transmittance.
•
ASTM C 1155-95 Standard Practice for
Determining Thermal Resistance of Building
Envelope Components from the In Situ Data.
•
ASTM 1046-95 Standard Practice for In Situ
Measurement of Heat Flux and Temperature on
Building Envelope Components

Measurement locations and sensor labellingNumber of measurement locations
2
Cable length per location
location 1: 10 m
location 2: 20 m
Included sensors location 1
heat flux: 1 x HFP01-10 with 10 m cabletemperature and temperature difference:
1 x TC-10 matched thermocouple pair with 10 m cablemarking “TC-1 inside” and “TC-1 outside”
Included sensors location 2
heat flux: 1 x HFP01-20 with 20 m cabletemperature and temperature difference:
1 x TC-20 matched thermocouple pair with 20 m cablemarking “TC-2 inside” and “TC-2 outside”
Cable markers heat flux sensor
2 x sticker, 1 x at sensor and 1 x cable end, wrappedaround the heat flux sensor cable. Both stickers show
sensitivity and serial number.

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Heat flux sensor mounting andorientation
Cable markers temperature sensors

recommended orientation is with the red face of theheat flux sensors facing indoors, and the blue facemounted at the indoor walls
location 1: TC-1 inside and TC-1 outside
location 2: TC-2 inside and TC-2 outside

Table 3.1.1 Specifications of TRSYS20 (started on previous page, continued on next page)
Rated operating conditions
Rated operating temperature range
IP protection class
Rated operating relative humidity range
Storage and transport
Storage

HFP01 and TC: -30 to +70 °C
MCU: -20 to +50 °C
see individual components below.
0 to 100 %when not in use TRSYS20 should be stored inside its
carrying case in a dry place. TRSYS20 MCU should be
stored with the dedicated dust caps placed onconnectors.
approx. 8 kg

Net weight total TRSYS20 including
carrying case
Gross weightapprox. 11 kg
Carrying casebox of 480 x 390 x 190 × 10-3 m
MEASUREMENT AND CONTROL UNIT (MCU)
Rated operating voltage
Recommended operating voltage
Power consumption
12 VDC connector type on MCU

10 – 16 VDC
12 VDC
<1W

Maximum power supply cable length
Sample rate
Stored measurements

1.8 m
1 sample/s
10 min averages of heat flux, temperature andtemperature differences; instantaneous values ofpanel temperature, heat flux sensor 1 sensitivity, heat
flux sensor 2 sensitivity

Storage capacity
MCU datalogger> 30 days
Campbell Scientific CR1000X Measurement andControl datalogger
IP54

Bulgin Standard Buccaneer®, PX0735/P, 2 poleconnector with pins

Ingress protection rating
Indicator LEDs
Power switch / LED
red LED is on when power is supplied to MCU
Running LED
green LED is on when measurement is running
Internal battery for battery-backed memory and clock
Internal system battery
AA, 2.4 A∙hr, 3.6 VDC (Tadiran, TL-5903/S)
Internal battery replacement interval
3 years, can be replaced by the user
USB connector
Connector type on MCU
USB-B socket
USB cable typeshieldedMaximum USB cable length
2.0 m
Ethernet connector
Connector type on MCU
RJ45 (shielded)
Isolation/protection
magnetic isolation
TVS surge protection
Ethernet cable typeshieldedMaximum ethernet cable length
30 m
User interface
Hardware connection to PC
USB orethernet (preferred for long-term use)
User interface on PC
web interface
Web browser requirement
HTML 5 support
Supported web browsers
Chrome 10

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Firefox 4Internet Explorer 9
Opera 11
Safari 5or later
POWER SUPPLY UNIT (PSU)
Power supply model
Input voltage
Input frequency
Input plug typeOutput voltage
Output current
Output cable length
Output connector type
Ingress protection rating

Mean Well, GEM60I12(similar power supplies may be used)
100 - 260 VAC
50 / 60 Hz
Type A/B (USA)Type C/F (EU)Type G (UK)Type I (AU)12 VDC
4.5 A
approx. 1.0 m
Bulgin Standard Buccaneer®, PX0736/S, 2 poleconnector with sockets
IP22

Table 3.1.1 Specifications of TRSYS20 (started on previous pages).
HFP01 HEAT FLUX SENSOR
Specifications
Guard width to thickness ratio
Measurement function
Calibration uncertainty HFP01 heat flux
sensors
Ingress protection rating
TC MATCHED THERMOCOUPLE PAIR

see HFP01 manual
5 (as required by ISO 9869 D.3.1)
Φ1 = U1/S1
Φ2 = U2/S2± 3 % (k = 2)
IP67

Thermocouple type

IEC 60584-3: 2007 type KX

Measurement function

ΔT1 = T1, indoor – T1, outdoor
ΔT2 = T2, indoor – T2, outdoor< ± 0.1°C(required by ISO 9869, paragraph 5.2)
IP67

Acceptance interval temperature
difference measurement
Ingress protection rating
INSTALLATION AND USE
Performing a representative
measurement
Installation
Sensor mounting

CALIBRATION AND FUNCTIONAL TEST
Performance verification

TR S YS 20 man u al v 2 301

see the chapter on standards and recommended
practices for use and the chapter on installation of
HFP01 and TC
see the chapter on standards and recommended
practices for use and the chapter on installation of
HFP01 and TC
for mounting sensors on walls, we recommend use of
double-sided “removable” carpet laying tape such as
TESA 4939, which has free removability up to 14 days
from the most common surfaces (needs to be tested
individually before usage)
via functional test

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Calibration traceability
Calibration uncertainty HFP01 heat flux
sensors
Acceptance interval temperature
difference measurement
Recommended recalibration intervalElectromagnetic Compatibility (EMC)

HFP01, TC and MCU are traceable to SI units± 3 % (k = 2)

Emission standards

EN-IEC 61326-1 (2013)
EN-IEC 61326-1 (2021)
EN-IEC 61000-3-2 (2014), Class A
EN-IEC 61000-3-2 (2019) + AC (2021), Class A
EN-IEC 61000-3-3 (2013) + A1 (2019) + A2 (2021) +AC (2022)
Light industrial and domestic environments, Class B
EN-IEC 61326-1 (2013)
EN-IEC 61326-1 (2021)
Industrial

Emission limits
Immunity
Immunity levels

TR S YS 20 man u al v 2 301< ± 0.1°C(required by ISO 9869, paragraph 5.2)
2 yr

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3.2 Dimensions of TRSYS20

Figure 3.2.1 Dimensions of TRSYS20 MCU in x 10-3 m.

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4 Preparation of an experiment
As a preparation, prior to performing an experiment, preferably the operator should readthis manual. Furthermore, Hukseflux recommends that users familiarize themselves withthe applicable ISO and ASTM standards.

4.1 Preparing the equipment
Prior to shipping TRSYS20 system to a measurement site, the user should check that theitems listed in section 1.2 are present and accounted for.
Additionally, the user will need the following items not included with TRSYS20:••••

Double-sided tape or glue for mounting the heat flux and temperature sensors (e.g.
TESA 4939)
Cable ties to be used as a strain relief for the sensor cables
Sandpaper or cleaning wipes for cleaning the surface prior to mounting the heat flux
and temperature sensors
A laptop to connect with TRSYS20 MCU to start and monitor measurements

Optionally the user may want to use the following items not included with TRSYS20:•••

A power extension cord to connect the PSU to mains
A shielded ethernet cable (max. 30 m long) to connect the MCU to a LAN if desired
A thermal imaging camera to aid in the site selection for the heat flux andtemperature sensors.

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5 TRSYS20 MCU system setup
This chapter describes how to setup the TRSYS20 MCU. The following steps should becompleted:
1.
2.
3.
4.

Setting up connection with the MCU
Setting the MCU clock
Setting the net-frequency filter
Verifying the programmed HFP01 sensitivities

5.1 Setting up connection
TRSYS20 is operated via a laptop or PC. TRSYS20 MCU acts as a webserver such that theuser interface can be accessed using a web browser. The user interface allows the user
to start and monitor measurements. The TRSYS20 MCU can be connected either via USB
or ethernet. If a long-term connection is desired (> 1 day) the preferred method is touse an ethernet connection, to guarantee a stable measuring performance.

5.1.1 Connection via USB
To use this option, TRSYS20 MCU should be connected directly to a free USB port on the
PC or laptop using the included USB-A to USB-B cable. When using a USB connection, theMicrosoft RNDIS protocol will be used to provide a ‘virtual ethernet link’ or ‘ethernet overUSB’.
Use of the ethernet over USB connection requires the Microsoft RNDIS drivers to beinstalled. The drivers should either be installed by default or install automatically uponconnecting TRSYS20 MCU to the PC. If the drivers are not automatically installed, install
the USB drivers using the Campbell Scientific Device Configuration Utility, see theappendix.
To access the graphical user interface, open a compatible web browser (seespecifications chapter for a list of compatible web browsers) and enter the following URL
into the address bar: http://www.linktodevice.com.
Alternatively, one can use the IP address to open the graphical user interface. To do soenter ‘http://’ followed by the IP address into the address bar. By default, the IP address
is 192.168.66.1, such that http://192.168.66.1 should be entered into the address bar

5.1.2 Connection via ethernet
To use this option, the MCU and the PC or laptop should be connected to the same LAN.
The MCU will be assigned an IP address automatically.
To access the graphical user interface, open a compatible web browser (seespecifications chapter for a list of compatible web browsers) and enter the following URL
into the address bar: http://tpsys20_nnnnnnn, where nnnnnnn must be replaced by the
7 digit serial number of the MCU. The MCU’s serial number can be found on the productcertificate and on the MCU itself.
If the network does not allow for systems to assign their own name, the IP address canbe used to open the graphical user interface. To do so enter ‘http://’ followed by the IP
address into the address bar of the web browser.

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The IP address of the MCU can be found using either a general purpose IP scanner, theCampbell Scientific LoggerLink Mobile Apps for iOS and Android systems, available fromhttps://www.campbellsci.com/loggerlink or the Campbell Scientific Device Configuration
Utility available from https://www.campbellsci.com/devconfig.
Once a connection to the TRSYS20 MCU has been established, it is recommended tobookmark the URL in the web browser or to create shortcut on the desktop.
NOTICETo avoid ground loops, do not connect the ethernet port and the USB port of
the TRSYS20 MCU at the same time.

NOTICE
When connecting the MCU via ethernet use a shielded ethernet cable with amaximum length of 30 metres.

5.1.3 Logging into the TRSYS20 MCU
To make sure the TRSYS20 MCU can only be controlled by the authorised users on ashared network, first time use in a new browser or PC requires the correct credentials. A
pop-up will appear asking you to enter your credentials. The credentials are:Username: TRSYS20
Password: serial number of the TRSYS20 MCU

5.2 Setting the clock
TRSYS20 system clock is used to generate datetime stamps for the measurements. Prior
to using the system the clock must be set. To set the clock: in the interface select the
Settings tab, click the Set clock button. This will open a new window. Click the
Sync MCU clock button. This will synchronize the MCU time to the PC time. See figure
5.2.1.

Figure 5.2.1.: Synchronizing the MCU clock with the PC clock.

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5.3 Setting the net frequency filter
TRSYS20 uses a net frequency filter to reduce interference from power lines with theheat flux, differential temperature and temperature signals. The net frequency filter must
be set for the region in which the system is used. To set the net frequency filter: in theinterface select the Settings tab, in the Net frequency box select the Net frequency
filter drop down list and select the net frequency for your region (e.g. 50 Hz for Europe
or 60 Hz for North America). After setting the net frequency the MCU will restart. This
may take a minute. The web interface may have to be refreshed.

5.4 Verifying the programmed HFP01 sensitivity
HFP01 heat flux plates are calibrated on an individual basis at the factory. To obtaincorrect heat flux measurements the sensitivities of TRSYS20’s heat flux sensors must be
programmed in the TRSYS20 MCU through the user interface. The sensitivities are
preprogramed at the factory.
NOTICEThe HFP01 heat flux sensor parameters in TRSYS20 MCU must be set suchthat they match the values on the calibration certificate. Failure to enter thecorrect sensitivities into the TRSYS20 MCU may lead to invalid measurement
results.
To verify that the sensitivities have been programmed correctly select the Settings tabin the interface, and compare the values in the Current sensitivity column in the
Calibration data box to the values found on the supplied calibration certificates or at
the label at the end of the sensor cable.
In case the values are incorrect, enter the correct values found on the calibration
certificate into the fields in the New sensitivity column in the Calibration data box.
Once the values have been entered correctly click the Update calibration data button.
Upon clicking the button the values in the Current sensitivity column will be updated.

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6 Installation of sensors: HFP01 and TC
This chapter describes how to install the TRSYS20 sensors on a building envelope
component (wall) that is being investigated. It is assumed that the user has completed
the system setup described in chapter 5.
TRSYS20 has two sets of sensors. Each set consists of a heat flux sensor, an indoor
temperature sensor and an outdoor temperature sensor.
First the user must select suitable locations for mounting the sensors. The location
should be representative for the majority of the building envelope component being
studied. Placement near cracks, thermal bridges, corners, heating or cooling devices
should be avoided. See section 7.1 for further recommendations. A thermal imaging
camera can be used as an aid in finding a suitable location.
Once a suitable location has been found the sensors must be mounted. The indoor
temperature sensor and the heat flux sensor are normally mounted as close as possibleon the inside of the building envelope component. The outdoor temperature sensor ismounted on the outside of the building envelope component as close as possible to theindoor sensors. It is strongly recommended to place the MCU and PSU indoors. Prior toplacing the sensors, the mounting surface should be cleaned using e.g. sandpaper orcleaning tissues. Next the sensors can be mounted. Air gaps between the heat flux
sensor and the building envelope component should be avoided in order to minimize
thermal contact resistance. For smooth mounting surfaces double side tap may suffice,while for rough mounting surfaces a silicone glue might be more appropriate.
Movement of the sensors during the measurement should be prevented. The sensors
should be mounted in a manner that will last for the duration of the experiment. It isstrongly recommended to use cable ties as cable strain relieves.
Section 6.1 provides additional information on selection of suitable sensor locations,orientation of sensors and mounting of sensors.
NOTICEDo not lengthen or shorten the sensor cables. Modification of sensor cables
voids the thermocouple pairs being matched, may negatively affectelectromagnetic immunity and voids the EMC declaration.

6.1 Site selection and installation
Table 6.1.1 Recommendations for installation of heat flux sensors and temperature
sensors in building physics (continued on the next page).
Location

Preferably mount heat flux sensors indoors and not outdoors
Preferably use a large wall section which is relatively homogeneousin the northern hemisphere, north-facing walls are preferred
Do not exposure sensors to sun, rain, etc.
Do not expose indoor sensors to drafts and lateral heat fluxes
Do not mount sensors in the vicinity of thermal bridges, cracks, heatingor cooling devices and fans

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Close window blinds and curtains
Switch off artificial light sources
For detailed analysis of a single building element users may consider toinstall one heat flux sensor indoors, and the other outdoors. Measuring
on two sides permits a detailed analysis of the thermal response time.
For mounting sensors on glass windows: see paragraph 4.3.1.
Orientation

The two heat flux sensor sides are equivalent.
The two temperature sensors of the matched thermocouple pair TC areequivalent.
Recommended orientation is with the red face of the heat flux sensors
facing indoors, and the blue face connected to the indoor wall. This
generates a positive output signal when the heat flux direction is fromindoors to outdoors.
The thermocouples of the TC pair of location 1 are labelled TC-1-inside
and TC-1-outside. In case the temperature of TC-1-inside is greater thanTC-1-outside the difference has a positive sign.
Reversing the heat flux sensor orientation or the positions of the two
sensors of the TC pair will result in a change of sign of the heat flux- or
temperature difference output. If necessary, this may be compensated in
the post processing for example by giving the sensitivity a negative sign.

Performing a
representative
measurement

It is recommended to use 2 sets sensors on the same wall or building
envelope component. This redundancy improves the assessment of themeasurement accuracy.

Creating atemperature
difference

For the measurement of thermal resistance of walls it is best to have aconstant high level heat flux; strongly cooled or strongly heated rooms
are ideal. We recommend activating heaters or air conditioning to create
optimal conditions.

Mechanical mounting

Avoid any air gaps between sensors and wall. Air thermal conductivity isin the 0.02 W/(m·K) range, while a common glue has a thermal
conductivity around 0.2 W/(m·K). A 0.1 x 10-3 m air gap increases theeffective thermal resistance of the sensor by 60 %.
We recommend use of double-sided “removable” floor laying tape such as
TESA 4939, which has free removability up to 14 days from the mostcommon surfaces (needs to be tested individually before usage).
For thermocouple mounting the same tape may be used as for the heat
flux sensors.
For long-term installation and for filling up large gaps, use silicone
construction sealant, glue or adhesive, that can be bought in construction
depots. During curing of the silicone, typically 24 h, the sensor must be
temporarily held in place by other means.
We discourage the use of thermal paste because it tends to dry out.
Silicone glue and double sided tape are more stable and reliable.
Usually the cables are provided with an additional strain relief, forexample using a cable tie mount as in figure 7.1.1.

Added temperature
sensors

For Λ-value: temperature sensors should measure wall surface
temperature. They are typically located close to the sensor attached toboth sides of the wall.

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For R-value: temperature sensors should measure ambient air
temperature. They are typically located close to the sensor at both sidesof the wall, however not attached to the wall. Ambient air temperature
sensors should be shielded from solar radiation.
Avoiding spectral
errorsIn case of exposure solar radiation or to artificial light sources, thespectral properties of the sensor surface must match those of the wall.
This is attained by covering the sensor with paint or sheet material of thesame colour as the wall.

Figure 6.1.1 Installation of HFP01 on a wall using two-sided “removable” floor laying
tape such as TESA 4939, and a strain relief of the cable using a cable tie mount equippedwith the same floor laying tape as adhesive. TC temperature sensors may be mounted in
the same way.

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7 Performing measurements
This chapter describes how to start measurements, monitor measurement progress andretrieve data from the MCU. It is assumed that the user has completed the system setup
described in chapter 5 and has installed the sensors as outlined in chapter 6.

7.1 Starting an experiment
To start an experiment, select the Measurements tab in the interface. In the Next
experiment box enter a description of the building envelope component to bemeasured. To start the measurement, click the Start button in the Control box. The
system status should change to “RUNNING”, the green indicator in the Control box
should light up and the green measurement running LED on the TRSYS20 MCU should
light up.

7.2 Monitoring measurements
A typical measurement duration is 1 to 2 weeks, with a minimum of three days. During
the measurement the web interface can be used to obtain an indication of the data
quality.
In the web interface select the Preliminary results tab. In the Heat flux-vstemperature box a scatter plot of the measured heat flux versus the measured
differential temperature is displayed. The graph can be used to visually inspect if
sufficient correlation between heat flux and temperature is present.
In the Convergence monitor box a thermal resistance (R-value) versus time plot isdisplayed. For sufficiently long measurement duration it is expected that the computed
R-value gradually converges to a fixed value. The graph may be used to visually inspect
the convergence. It is important to note that the y-scale will automatically rescale. The
results are also listed in table format.
The Measurement results and quality indicators box displays the preliminary values
for the thermal resistance (R-value) of the building envelope component. The values arecalculated using the average method described in the ISO 9896 standard (or see section
2.2.2 ,method 1), which is identical to the summation technique described in the ASTM C
1155 standard. It should be noted that these values are intended as preliminary values
only. More sophisticated analysis as described in the relevant standards may be required
and is the responsibility of the user. Raw measurement data can be downloaded in CSV
format for further analysis.
Apart from the preliminary three quality indicators are displayed, that are based onrequirements set in the ISO 9896 standard:•••

Duration: indicates if the measurement duration exceeds the minimum
requirement of 72 hours.
Convergence: indicates if the current value of the thermal resistance deviatesfrom the thermal resistance 24 hours ago by less than 5 %Consistency: indicates if the thermal resistance computed from first 2/3rds of thedata differs from the thermal resistance computed from the final 2/3rs of the databy less than 5 %.

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Typically, the two TRSYS20 sensor sets are placed on the same building envelope
component to allow for a redundancy check. In that case the user should verify that thethermal resistances for the two measurement locations are comparable.
Apart from monitoring the measurements via the web interface it is strongly
recommended to visually inspect the sensor mounting at regular intervals during theexperiment. In some cases, sensors may detach from the surface of the building
envelope component. Sensors detaching from the surface of the building envelope
component are a source of impermissible errors.
NOTICE
It is strongly recommended to inspect sensor mounting at regular intervals
during a measurement. Poor contact between sensors and building envelope
component will lead to invalid results. Depending on the mounting method
thermal contact may deteriorate over time.
Once the user is satisfied by the amount of data collected, the user may finish themeasurement by clicking the Stop button in the Control box in the Measurements tab.
The MCU will store the data on the CRD drive and the results will then be available fordownloading and further analysis.

7.3 Retrieving measurement data
To download data from the latest measurement, click the Download data button in the
Data box on the Measurements tab. Note that data can only be downloaded after themeasurement is complete. Details about the raw data file format can be found inappendix 11.
Data from previous measurements may be accessed through the record browser. To
open the record browser, click the Browse records button in the Data box on the
Measurements tab.

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8 Data analysis tool
The data analysis required to determine the thermal resistance from the measurement
data is the responsibility of the user and should be performed following the practices
described in the ISO and ASTM standards. To help the user get started with the data
analysis, Hukseflux provides a data analysis tool in the form of an excel template. The
data analysis tool uses the average method described in the ISO 9869-1 standard, which
is similar to the summation technique described in the ASTM standard. It is up to theuser to determine if this method is appropriate or not.
The data analysis tool can be downloaded from the TRSYS20 webinterface.

8.1 Importing the data
First the data must be downloaded from TRSYS20. TRSYS20 data files have comma
separated (CSV) format. The files can be opened using Excel. Upon opening the file Excel
will present the user the Text Import Wizard. Follow the steps in the wizard to open
the file. Finally, the data must be copy-pasted into the raw_data tab in the excel
template.

8.2 Viewing results
Once the data has been imported into the excel template, the results can be reviewed in
the results tab.
The tab shows the resulting thermal resistances for both measurement locations, threemeasurement quality indicators as outlined in section 7.1 of the ISO 9869 standard, ascatter plot of heat-flux vs differential-temperature and a convergence plot for thethermal resistance estimator.

Figure 8.2.1: The results tab of the TRSYS20 data analysis tool.

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9 Uncertainty evaluation
The formal evaluation of uncertainty should be performed in accordance with ISO 98-3
Guide to the Expression of Uncertainty in Measurement, GUM.

9.1 Heat flux measurements
In case of heat flux sensors, the measurement uncertainty is a function of:• the calibration uncertainty of the heat flux sensor as well as the datalogger’s
analogue-to-digital converter• differences between reference conditions during calibration and measurement
conditions, for example uncertainty caused temperature dependence of the sensitivity• the duration of sensor employment (involving the non-stability)• application errors: the measurement conditions and environment in relation to thesensor properties, the influence of the sensor on the measurand, the influence of thetape or silicone glue used to mount the heat flux sensor, the representativeness of themeasurement location
Under ideal conditions, measurements of heat flux in building physics may attain
uncertainties in the ± 6 % range. Typically, however, application errors are significant.
Therefore, it is not possible to give one figure for heat flux sensor measurement
uncertainty. Statements about the overall measurement uncertainty should be made on
an individual basis, taking all these factors into account.
For more information on the measurement uncertainty of the heat flux sensors the user
is referred to the HFP01 manual.

9.2 Temperature difference
The temperature difference measurement is accurate within 0.1 °C over the entire
temperature range.

9.3 Thermal resistance
ISO 9869 chapter 9 shows examples of uncertainty evaluation, for thermal resistancemeasurement. This uncertainty budget also includes contributions from the temperature
measurements and dynamic effects. It arrives at typical uncertainties of the order of ±20 % of on-site measurements of thermal resistances.
Corrections may be applied according to chapter 8 of ISO 9869. These corrections
include corrections for the thermal resistance and corrections for the finite dimension of
the sensor. ISO also calls the latter the operational error, we use the term deflection
error.

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10 Maintenance and trouble shooting
10.1 Recommended maintenance and quality assurance
TRSYS20 measures reliably at a low level of maintenance. Unreliable measurement
results are detected by scientific judgement, for example by looking for unreasonably
large or small measured values. The preferred way to obtain a reliable measurement is aregular critical review of the measured data, preferably checking against othermeasurements, or by comparing results of the two heat flux sensors and twothermocouple pairs when mounted side by side.
Table 10.1.1 Recommended maintenance of TRSYS20. If possible, the data analysis isdone on a daily basis.
MINIMUM RECOMMENDED HEAT FLUX SENSOR MAINTENANCE
INTERVALSUBJECTACTION1

everydata analysis
measurement

Compare measured data between the measurement locations.
Look for any patterns and events that deviate from what isnormal or expected. Compare to acceptance intervals. Plot
heat flux and temperature data against the othermeteorological measurands. Inspect cable quality, inspect
mounting

2

12 months

inspection

Side by side comparison of the two heat flux sensors and twothermocouple pairs when mounted side by side.

3

2 years

recalibration

Recalibration of heat flux plate, matched thermocouple pairs
and MCU by the sensor manufacturer

lifetime
assessment

Judge if the instrument will be reliable for another 2 years, or
if it should be replaced

4
5

3 years

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Replace the battery in the MCU, this can be done by the user

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10.2 Trouble shooting
Table 10.2.1 Trouble shooting for TRSYS20.
The HFP01 sensor
signal is incorrect,
erratic or out of
range

Check the programmed sensitivity in the TRSYS20 web interface. Make surethe programmed sensitivity matches the sensitivity on the calibration
certificate.
Check if the sensor reacts to heat: Expose the sensor heat, for instancetouching it with your hand. The signal should read > 2 x 10-3 V now.
Touching or exposing the red side should generate a positive signal, doing
the same at the opposite side the sign of the output voltage reverses.
Visually inspect the sensor cable for damage.
Open the MCU. Locate the sensor wires. Verify that they are connected to
the CR1000X datalogger. If necessary, tighten the screws on the screw
terminal block on the datalogger using a Phillips head screwdriver. Check if
this resolves the problem. If this does not resolve the problem, disconnect
the HFP01 from the CR1000X datalogger using a Phillips head screwdriver.
Check the electrical resistance of the sensor between the green [‒] andwhite [+] wires. Use a multimeter at the 100 Ω range. Measure the sensor
resistance first with one polarity, then reverse the polarity. Take theaverage value. The typical resistance of the wiring is 0.1 Ω/m. Typicalresistance should be the nominal sensor resistance of 1 to 4 Ω plus 1.5 Ω forthe total resistance of two wires (back and forth) of each 5 m. Infinite
resistance indicates a broken circuit; zero or a low resistance indicates ashort circuit.
In case a HFP01 heat flux sensor is malfunctioning contact Hukseflux
Thermal Sensors to discuss replacement.

The TC matched
thermocouple pairsignal is incorrect,
erratic or out of
range

Verify that the MCU panel temperature value is reasonable. Next check
which of the TC matched thermocouple values are incorrect, erratic or out ofrange: only the indoor temperature, only the outdoor temperature or both.
Check if the sensors react to heat: Expose the sensor heat, for instancetouching it with your hand.
Visually inspect the thermocouple cables for damage.
Open the MCU. Locate the sensor wires. Verify that they are connected to
the CR1000X datalogger. If necessary, tighten the screws on the screw
terminal block on the datalogger using a Phillips head screwdriver. Check if
this resolves the problem. If this does not resolve the problem, disconnect
the thermocouple from the CR1000X datalogger using a Phillips headscrewdriver. Check the electrical resistance of the sensors between thegreen [‒] and white [+] wires. Use a multimeter at the 100 Ω range.
Measure the sensor resistance first with one polarity, then reverse thepolarity. Take the average value. The typical resistance of the wiring is 0.1Ω/m. Typical resistance should be the nominal sensor resistance of 1 to 4 Ωplus 1.5 Ω for the total resistance of two wires (back and forth) of each 5 m.
Infinite resistance indicates a broken circuit; zero or a low resistanceindicates a short circuit.
In case a temperature sensor is malfunctioning contact Hukseflux Thermal
Sensors to discuss replacement.

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10.3 Calibration and checks in the field
The recommended calibration interval of the TRSYS20 and its individual components is 2
years. Recalibration of sensors and MCU is ideally done by the sensor manufacturer.
On-site performance verification is possibly by mounting heat flux sensors andthermocouple pairs side by side. Alternatively heat flux sensors may be stacked.

10.4 Storage
MCU and sensors should be stored in a dry place with the dedicated dust caps placed on
the connectors.

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11 Appendices11.1 TRSYS20 data table
Raw data can be downloaded from the TRSYS20 MCU in .csv format. The variables in theraw data file are listed in table 11.1.1.
Table 11.1.1 Explanation of variables and parameters used in the HF_10min data table.
PARAMETERS USED IN HF_10min data table
PARAMETERDESCRIPTIONUNITSTIMESTAMP

Date and time

YYYY-MM-DD HH:MM:SS

RECORD

Number of the record-

experiment_id

Number of the experiment-

panel_temperature

Temperature of the MCU panel°Csensitivity_hf(1)Sensitivity heat flux plate 1

x 10-6 V/(W/m²)

sensitivity_hf(2)Sensitivity heat flux plate 2

x 10-6 V/(W/m²)

heat_flux_Avg(1)Heat flux location 1(10 minute average)

W/m2

heat_flux_Avg(2)Heat flux location 2(10 minute average)

W/m2

temperature_inside_Avg(1)Indoor temperature location 1(10 minute average)°C

temperature_inside_Avg(2)Indoor temperature location 2(10 minute average)°C

temperature_difference_Avg(1)Temperature difference location 1(10 minute average)

K

temperature_difference_Avg(2)Temperature difference location 2(10 minute average)K

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11.2 EU declaration of conformity

We,

Hukseflux Thermal Sensors B.V.
Delftechpark 31
2628 XJ Delft
The Netherlands

hereby declare under our sole responsibility that:
Product model
Product typeTRSYS20High-accuracy building thermal resistance measuringsystemconforms with the following directive(s):2011/65/EU, EU 2015/863
2014/30/EU
2014/35/EU

The Restriction of Hazardous Substances Directive
The Electromagnetic Compatibility Directive
The Low Voltage Directive

This conformity is declared using the relevant sections and requirements of the following
standards:
EMC Emission
EMC Immunity
ReportEN-IEC 61326-2-1:2013, Class B
EN-IEC 61326-2-1:2013, Industrial
20230132RPT02

Eric HOEKSEMA
Director
Delft, 17 April, 2023

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© 2023, Hukseflux Thermal Sensors B.V.
www.hukseflux.com
Hukseflux Thermal Sensors B.V. reserves the right to change specifications without notice.