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HFS01 High Heat Flux Sensor

High heat flux sensor for concentrated solar radiation and flames, water cooled

HFS01 is a water-cooled sensor that measures high-level radiative and convective heat fluxes. It is designed for studies of concentrated solar irradiance (800 x concentrated direct solar radiation) and high-intensity flames (gas burners, coal fires). HFS01 has a very robust all-metal / ceramics instrument body and sensor, and is equipped with a high-temperature cable to survive the extreme conditions of a typical experiment.

The HFS01 measures heat flux in the range of (0 to 800) x 10³ W/m²; the extremely high fluxes as generated by flames and solar concentrators. Equipped with a black absorber, the instrument is designed for measurement in an environment in which heat flux includes radiation as well as convection. HFS01’s thermopile sensor generates an output voltage proportional to the total absorbed heat flux. The sensor must be water-cooled, usually by tap water. A removable flange that can be used for mounting is supplied with the sensor. Also, a type K thermocouple is included, to measure the sensor body temperature.

The part of the cabling closest to the sensor is a special high-temperature metal sheathed cable with an interlocked spiral stainless steel armour. The high-temperature cable and armour withstand temperatures up to 900 °C. Because the sensor body is water cooled, it will remain relatively cool. The surface temperature of the sensor may reach 650 ˚C. The low-temperature extension cable has a jacket of PTFE type plastic.

The HFS01 sensor can also be ordered without black coating, so that HFS01’s absorption of radiation is reduced, while it remains sensitive to convective radiation. Users may also coat HFS01 with their own coating, to create a different response to radiation.

HFS01 has several advantages:

  • very robust all-metal / ceramics instrument body and sensor
  • high-temperature signal cable
  • signal wires electrically insulated from the sensor body and from cooling water

Using HFS01 is easy. It can be connected directly to commonly used data logging systems. The heat flux, in W/m², is calculated by dividing the HFS01 output, a small voltage, by the sensitivity. The sensitivity is provided with HFS01 on its product certificate. Equipped with heavy-duty cabling and a fully stainless steel casing which prevents moisture from penetrating the sensor, HFS01 has proven to be very reliable.

HFS01 calibration is traceable to international standards. The factory calibration method follows the recommended practice of ASTM C1130-07 (2012).


  • longer cable (specify total cable length for both cable types in m)
  • connector at HFS01 cable end
  • low-temperature extension cable with 2 connectors, matching cable connector and chassis connector
  • chassis connector with internal wiring (colour code of wiring identical to cable colour code)
  • blank metal sensor surface, no coating

Suggested use

  • solar concentrators
  • flame research
  • fluidised beds