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Enabling better global research outcomes in soil, plant & environmental monitoring.

Hukseflux HTR01 Calibration Heater

Hukseflux, the world market leader in heat flux sensors, simplifies heat flux sensor calibration. HTR01 is a heater with 4-wire connection with a known surface area and electrical resistance. It is used for calibration and functionality checks of FHF-type heat flux sensors. Users can now easily and objectively check their sensor performance before and after use. See also model FHF02SC heat flux sensor with integrated heater.

HTR01 heater for calibration and verfication of performance of FHF-type sensors

Measuring heat flux, users may wish to regularly check their sensor performance. A quick check or if you like even a formal calibration is now possible with HTR01 plus some accessories that most laboratories will have in-house. The HTR01 heater has a well characterised a traceable surface area and electrical resistance.

HTR01 is a foil heater. Either it can be used as a general-purpose heater or it can be used in combination with foil heat flux sensors such as FHF01 and FHF02 for test and calibration purposes.

Building physics / insulation, thermal comfort and energy budget measurement

In building physics, the investigation of the insulation capabilities of building materials is an important subject of study. Hukseflux is the market leader in heat flux measurement related to building physics. The most commonly used sensor is model HFP01. Hukseflux supplies turn-key systems for analysis of thermal resistance of building envelopes and elements.

 


Application: Solar heating in building automation


Insulation, thermal comfort and energy budget measurement

In building physics, the focus of measurement is on several subjects, for example:

  • analysis of indoor climate
  • studies of the insulation and thermal resistance of building envelopes
  • studies of roof reflectance
  • studies of solar transmission of glass

What is measured

Typical measurements required in such experiments, are:

  • heat flux, for example on walls
  • temperature differences over walls
  • absolute temperatures
  • solar radiation
  • net radiation

Heat flux sensors measure heat transfer. More specifically: the energy flux onto or through a surface, in [W/m²]. In reality, often this surface is the sensor itself mounted on a wall. The source of the heat flux may be:

  • conduction – heat flowing through a static, non-flowing material
  • radiation – heat transmitted, typically by visible or infra-red radiation
  • convection – heat transported by flowing fluids or gasses

Heat transfer is driven by temperature differences. Heat always flows from a source to a sink, from a hot to a cold environment.

For high–accuracy temperature difference measurement, matched sensor pairs are used; during production the accuracy of one sensor is checked relative to the other.

Pyranometers measure the radiation received by a plane surface from a 180 ° field of view angle. This quantity, expressed in W/m², is called “hemispherical” solar radiation.

In building physics most common parameters that we measure are:

  • incoming solar radiation
  • reflected solar radiation
  • roof reflectance (albedo)
  • reflectance of other components
  • solar transmission of window materials

Sensors of our pyrgeometer product line measure far infra red “longwave” radiation. The most common parameters that we measure are:

  • downwelling longwave radiation
  • upwelling solar radiation
  • roof or wall infra red “blackbody” equivalent temperature.

Two pyranometer measurements combined with two pyrgeometer measurements are used to calculate the net-radiation.

Specifications

Heat flux sensors, building envelope thermal resistance measuring systems, pyranometers, pyrgeometers and net radiation sensors must be optimised for the demands of different applications. Unique features typically required in building physics are:

  • heat flux sensors compliant with ISO 9869
  • heat flux sensors with sufficient sensitivity to measure in the 1 W/m² range
  • pyranometers suitable for roof reflectance measurement according to ASTM e1549
  • pyrgeometers measuring roof temperature over a large area
  • temperature difference measurement with an uncertainty of better than 0.1 °C over a large temperature range.

Selecting a set of sensors

We can assist you selecting a sensor. A typical checklist is:

  • what is the application; what must be measured, outdoors and indoors
  • are there any standards that you must follow
  • what are the accuracy requirements
  • how do I organise re-calibration
  • how can I mount instruments
  • what data acquisition do I have, can it measure in the millivolt range; if not what kind of input can it accept?
  • what other things must be measured; usually it is best to use one measurement system performing all measurements. Building physics experiments often have large numbers of temperature sensors. In many cased not the absolute but the relative temperature is important

What we contribute

Hukseflux provides a range of sensors and measuring systems for use in measurement of the energy budget of buildings and characterisation of construction materials. HFP01 heat flux sensor and TRSYS01 measuring system are widely used for on-site measurements on walls, windows and other construction elements. HFP01 heat flux plate is the de-facto standard for heat flux measurement on walls. In high accuracy flux measurement a typical station is equipped with two or more sensors for good spatial averaging.

Our TRSYS01 is a measuring system for analysis of the thermal resistance and the thermal transmittance of building elements by in-situ measurement.

TPSYS02 is used to characterise soils, cements and insulation materials. Our pyranometers are used to measure solar radiation on buildings and to measure solar transmission of windows and solar reflectance of roofs.

Sensors made by Hukseflux passed validation and acceptance testing for a large number of national research institutes.

Advantages

Depending on the exact requirement, we offer:

  • assistance – select the best sensors for your application
  • assistance – optimising the sensor – measuring system combination, also looking at the total system (our users often measure more than just radiation)
  • worldwide support – specialists available in the major economies
  • calibration support – efficient worldwide calibration organisation
  • proven performance – we have experience in most applications
  • traceability – formal metrological traceability to international standards
Power supply voltage
12 VDC
Heater area 2062 x 10⁻² m²
Heater resistance range 100 Ω (nominal)
Heater thickness 0.1 x 10⁻³ m
Operating temperature range -40 to +150 °C
Heater rated power supply 9 to 15 VDC
Standard wire length 2 m (2 x 2 wires)
Certificate supplied with a certificate stating surface area in [m²] and heater resistance in [Ω]
Requirements for testing metal heat sink > 1 kg; power supply 12 VDC; 0.2 A; insulation material; contact material such as glycerol or toothpaste
Options longer wire length upon request

Scientific research / heat and heat transfer measurement

Many engineering studies involve the measurement of transport of heat. The heat and heat transfer measurements are used for several purposes, including understanding the physics / main transport mechanisms and analysing energy balance (input – output) of a system. A good starting point for a heat transfer experiment is a heat flux measurement. Hukseflux has a full range of heat flux sensors. Do you have any questions about our products or would you like our support in setting up a measurement, don’t hesitate to contact us. At Hukseflux, we like having a good technical conversation.

Heat and heat transfer measurement

Many engineering studies involve the measurement of transport of heat. The heat and heat transfer measurements are used for several purposes:

  • to understand what is going on; the physics / main transport mechanisms
  • to distinguish between radiative, convective and conductive transport mechanisms
  • analysing energy balance (input – output) of a system
  • to derive material properties
  • to detect changes of state of materials for example chemical reactions, phase transitions
  • to detect changes in flow regime, transitions from laminar to turbulent flow
  • determining heat absorption or release in processes like condensation, boiling
  • analysing energy production in chemical reaction

We see different approaches:

  • comparative, taking one measurement as a reference point and comparing this to a measurement under similar but slightly different conditions
  • absolute, trying to establish absolute values in [W] or [W/m²]

What is measured

A good starting point for a heat transfer experiment is a heat flux measurement. Heat flux sensors measure heat transfer. More specifically: the energy flux onto or through a surface, in [W/m²]. In reality this surface is the sensor itself. The source of the heat flux may be:

  • conduction – heat flowing through a static, not-flowing material
  • radiation – heat transmitted, typically by visible or infra-red, radiation
  • convection – heat transported by flowing fluids or gasses

Heat transfer is driven by temperature differences. Heat always flows from a source to a sink, from a hot to a cold environment.

At the surface of a solid object, often the source of heat flux is a mixture of radiative and contributions.

Convective and conductive heat fluxes are measured by letting this heat flow through a heat flux sensor. Heat flux sensors are either mounted on a surface of a solid object or embedded into this object. Measuring convective heat flux, the sensor will typically be located on the surface of a solid object, and exposed to the convective flow; at the sensor surface, the convective flux is then converted into a conductive flux.

Radiative flux is measured using a heat flux sensor covered with a (black) radiation absorber. It is usually mounted on a solid, well conducting heat sink. The absorber converts radiative energy to conductive energy. However this sensor will also be sensitive to convective heat flux.

By covering a sensor with a radiation reflector, like a gold or aluminium foil, you can measure convective flux only.

A classic sensor combination to analyse heat transfer is:

  • heat sink with
  • a black coated heat flux sensor and
  • a gold coated heat flux sensor
  • a heat sink temperature measurement
  • an air temperature measurement

In some cases heat can be measured by electrical substitution. The heat generated by a test object is temporarily replaced by electrically generated heat. The system is thereby calibrated. Such a system typically includes:

  • heat sink with
  • a heat flux sensor
  • a resistor
  • the test object

Heat transfer is driven by temperature differences. Hukseflux can measure temperature differences with very high accuracy over a large temperature range. Accurate temperature difference measurement is essential for a good heat transfer experiment.

Specifications

Heat flux sensors manufactured by Hukseflux are optimised for the demands of different applications:

  • rated temperature range; we make sensor for use from -150 to + 900 °C
  • suggestions for absorbers and reflectors to mount on the sensors
  • rated heat flux range; from 0.01 to 200 000 W/m²
  • sensitivity / output signal
  • response time
  • chemical resistance, safety requirements; including sensors for potentially explosive environments
  • size, shape and spectral properties
  • optional on-site performance validation or self-calibration capabilities

Hukseflux can also supply temperature sensors to support heat transfer measurement:

  • matched thermocouple pairs, temperature difference measurement accuracy of better than 0.1 °C

 

Selecting a sensor

We can assist you selecting sensor and designing an experiment. For preparation, please read:

  • our note about general things to keep in mind when measuring heat flux, also showing different sensor models and their most common applications

a typical checklist is:

  • what is the application, what must be measured
  • what is the temperature range
  • what transport mechanisms do you expect; convective, radiative, conductive, and must they be separately measured
  • any requirements for size and shape
  • what are the accuracy requirements
  • how can I mount the sensor
  • what is the rated temperature range in °C
  • what are the expected temperature differences in °C
  • what is the rated heat flux range of all transport mechanisms in W/m²
  • what data acquisition do I have, can it measure in the millivolt range; if not what kind of input can it accept?
  • what other things must be measured; usually it is best to use one measurement system performing all measurements
  • any special requirements for example response time, spectral properties, ..

What we contribute

Hukseflux company started in 1993 making sensors for measurement of heat flux and heat transfer. We have designed and supplied sensors for many studies. Our experience includes a variety of environments such as coal fired boilers, fluidised beds, solar concentrators, offshore flare systems and blast furnaces. We are the market leader in industrial heat flux and heat transfer measurement.

Advantages

Hukseflux is the world market leader in heat flux measurement. We offer:

  • assistance – select the best sensors, heat flux as well as temperature difference, for your application
  • assistance – optimising the sensor – measuring system combination, also looking at the total system
  • worldwide support – specialists available in the major economies
  • traceability – formal metrological traceability to international standards.