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Environmental measurement & analysis
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Heat Flux Sensors

siy-fig01EKO Heat Flow Sensors are applied to measure the heat flow or thermal conductivity in materials and radiative IR flux emitted by body surfaces. The sensors are suitable for indoors applications, some models made for outdoors purposes and are available in different sizes and thickness. All sensors are extremely flat, which is a big advantage considering the minimum interference with the conditions of the testing area the thermal dynamics. Since sensor foils are relatively flexible those can easy be applied on curved surfaces and can be used in different applications to measure the performance of insulating materials in refrigerators, container walls, pipes, building constructions, etc.

A heatflux sensor is a thermopile sensor which generates an electric voltage proportional to the ∆T across the thermocouple hot and cold junctions. To generate a measurable voltage heat flux sensors have multiple thermocouples spread over the total area connected in series. EKO heatflux sensor have a vertical thermocouple  built up which means that all cold junctions and hot junctions are separated by the surface top and bottom side.

Energy flux can be measured in both directions, where the sensor will simply give a positive or negative voltage. The thermal conductivity measurement unit (W/m/K) is defined as the energy (W) needed to create a thermal potential (∆T) of 1 Kelvin (K) through a thermal conductor of a specific length (m). The radiative flux (W/m2) is defined as the energy (W) radiated or absorbed as a unit of surface area (m2). When the sensor is put at the top of a surface the thermal conductivity, thermal transmission, radiation and convection component are measured. When the sensor is placed in between to surfaces inside the object it measures the thermal transmission by means of thermal conduction. The heat flow (thermal conductivity) through the sensor is proportional to the inverse thermal resistance (1/R) multiplied by the temperature across the sensor (∆T).  

Models

Product Model Description
MF-180 Heat flux Sensor

MF-180 Heat flux Sensor

The MF-180 has a high sensitivity in spite of the small size. It is suitable for measuring a small …

MF-190 Heat Flux Sensor

MF-190 Heat Flux Sensor

The MP-190 is a large area (310 x 310mm) flexible thin foil heat flow sensor. It can be easily rolled …

MF-200 Heat Flux Sensor

MF-200 Heat Flux Sensor

The thinnest square size thermal conductivity sensor can be found in most general applications. For …

Specifications

Specifications MF-180 MF-180M MF-190 MF-200
Measurement place Indoor Outdoor Indoor  Indoor 
Operating temperature range (°C) -30°C ~ +120°C -30°C ~ +120°C -20°C ~ +120°C   -20°C ~ +120°C
Sensitivity constant (mV/W/m²) 0.028 0.025 0.20  0.006 
Temperature dependency (%/°C) -0.03 -0.03 <0.05  

Impedance (Ω)

150 - 550

150 - 550

 600 - 900

15 - 30 

Reproducibility (%) +/- 2% +/- 2% +/- 2%  +/- 2% 
Size (L x W x T, mm) 42 x 20 x 0.9 50 x 25 x 1.2 310 x 310 x 0.7   50 x 50 x 0.7
Weight (g) 1.1 1.8 100  3.3 
Substrate Teflon Teflon  Glass Epoxy Glass Epoxy 
Cladding Polyester Carbon FRP  Polyester Polyester 
Remarks All-purpose, small size, high sensitivity Water-proof, highly durable, robust Large size and very thin and flexible, low heat resistance  Very thin and flexible, low heat resistance 

Applications

Evaluation of floor heating systems

Evaluation of floor heating systems

Understanding of heat flow and thermal losses is inevitable during building design and engineering of energy-efficient floor heating systems. The MP-series heatflux sensors are perfectly ...

Energy saving and thermal engineering

Energy saving and thermal engineering

Evaluation of heat flow and thermal loss is valuable with respect to thermal engineering and energy-saving devices. Heat-flow is a physical phenomena occurring between two objects ...

Radiative heat from human body

Radiative heat from human body

A heatflux sensor is used for a real-time measurement of radiative heat from highly active human bodies Helping to determine the definition of human comfort Helping to determine bracing ...

Measurement of energy losses in building

Measurement of energy losses in building

The total thermal losses of building constructions strongly depends on the environmental conditions (Location) and building construction (Material). In situ measurements are possible ...

General Heat flux sensor applications

General Heat flux sensor applications

Measurement of the thermal loss from a building Evaluation of floor heating systems The total thermal losses of building constructions strongly depends on the environmental ...

Calibration Procedure & Traceability

All heatflux sensors are calibrated relatively to a standard heat flow sensor which was calibrated at EKO isntruments with an absolute calibrater.

 

The Heat Flow Sensors are calibrated according to the Guarded Hot Plate Method which is a absolute thermal conductivity measurement method for insulators and complies with JIS A 1412.  By measuring the voltage and applied power to the main hot plate, the heat flow which flow though the sample can be calculated taking into account the thermal conductivity from the sample temperature difference and thickness.

 

Recalibration

Changes in sensitivity is very small (<0.3%/1 year) if the heat flow sensor is used in normal application (temperature range, setup environment, etc.). Therefore, the recommended recalibration should be 3~5 years after the delivery.

Frequently Asked Questions

How to improve thermal contact of heatflux sensors

How to improve thermal contact of heatflux sensors

If a heat flux sensor does not make good thermal contact with the material to be measured, it will cause a local hot spot to form (or a cold spot in the case where the heat flux is ...

Heat Flux sensor low output Voltage

Heat Flux sensor low output Voltage

How to measure the low output voltage of a heat flow sensor?   In order to measure the output Voltage (µV - mV) , the measurement equipment should have a mV input rage ...