Applications of Thermopile Sensors or Detectors

Thermopile detectors have been gaining popularity and increasing widespread usage worldwide. As a detector or sensor, a thermopile can easily determine significantly low temperature when compared with a standard thermocouple device. The application of thermopile sensors and detectors has a wide range of applications starting from microwave ovens, medical devices, automotive controls, cloth dryers, mobile phones, printers, copiers, and so many other day-to-day products.

Categories of thermopile detection or sensing

The applications of thermopile detectors and sensors can be categorized into two sections:

  1. The category that comprises non-contact temperature measurements
  2. The second category includes gas detection and measurement of gas concentration

Temperature sensing and detecting

Single-element thermopile detectors and sensors with lower spatial resolutions are best for non-contact temperature measurements. The most common application is the human body temperature measurement device, like forehead, and in-ear thermometers and sensors for industrial process control. Because of the low thermal time constants, thermopile sensors are fast and can make quick measurements. Furthermore, thermopiles can function at DC and don’t require to be refreshed periodically with an external shutter mechanism. This enables real-time continuous temperature observations.

Thermal imaging

To yield thermal imaging, several independent thermopile pixels are arranged in a two-dimensional way. Starting from low resolution to a plethora of thermopile arrays are available. For instance, 8×8, 16×16, 32×32, 80×64, and 120×84 pixels are available. This enables the generation of thermal images with varying spatial resolutions for different applications in the industry. One of the prime interests includes individual detection in security and automation applications. Another area of interest is hot spot detection including a wide array of applications from industrial safety, consumer goods, fire suppression, and engineering.

Gas detection

Thermopile sensors and detectors can be utilized to perform gas concentration measurements and gas detection. The sensors follow the NDIR (NonDispersive Infrared) gas detection principle. Measuring the absorption of infrared radiation at a particular wavelength allows the detection of the specific gas concentration. To detect gas concentration, just one thermopile, and an infrared light source are required. Often two single or one dual thermopile sensors are used so that there is accuracy. The accuracy can be increased by doing away with drift over time of the infrared source emission. Thanks to the small size, and lower thermal mass, NDIR gas detecting with the help of thermopile sensors can be fast and efficient.

Hot spot detection

Thermopile arrays can easily acquire thermal images, thereby efficient hot spot detection application is efficient and hassle-free. Several fields in the industry demand information about existing or developing hot spots. It is useful in energy savings, preventing fire, and also making the right predictions for maintenance and repair. Stovetop monitoring and fire-risk sensing in waste plants, transportations, or public spaces are typical thermopile applications in hot spot detection.

Stovetop monitoring

The number one cause of fire accidents at home occurs from stovetops. Kitchen fire incidents are dangerous, thereby the need of preventing them. Often fire detectors used in the kitchens cause false alarms. Thanks to infrared thermopile detectors that offer correct alarms because the sensors are not impacted by haze or fog from cooking processes. Therefore, thermopile detectors and sensors can make the kitchen safer. Moreover, it can also be used to monitor stovetops and detect shutting the stove before reaching the critical temperature. Several countries have made stovetop monitoring compulsory as it enhances the independence of individuals in assisted living conditions, senior citizens, and people with disabilities.

Industrial process control

Several industrial applications don’t suit or desire contact-based temperature measurements. The contact-based measurement is slow and the object is also difficult to access. Non-contact temperature measurements are used in several industrial applications like glass fabrication, metal fabrication, the food industry, the pharmaceutical sector, and so on. Thermopile sensors and detectors have proven to be beneficial in industries mainly because of their easy measurement techniques of moving and vibrating objects. Furthermore, the sensors can be used in high voltage, explosive, corrosive environments.


Thermopile sensors and detectors prove to be beneficial in a wide array of industrial applications. Starting from process control, thermal imaging, gas detection, gas concentration sensing, hot spot detection, and person detection, thermopile sensors are the new standard of measuring temperatures on human bodies, and other objects around the world.

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