A Simple Overview of Thermopile: What are They and How Do They Work?


A thermopile is an electronic device that is responsible for converting thermal energy into electrical energy. It is a serial-interconnected pair of thermocouples consisting of two distinct materials featuring a large thermoelectric power and opposite polarities. This particular device produces greater voltage output. This article comprises the thermopile module letting one know all about thermopile.

What is Thermopile?

A thermopile, typically an electric device is constructed using a thermocouple series combination and its main function is o convert electrical energy into thermal energy. It is basically a set of thermocouples that are arranged in such a way that they measure small quantities of radiant heat. Additionally, according to the thermopile module, this device is a non-contact-based temperature sensor device that utilizes infrared radiation with an IR Absorber system for measuring the temperature. Compared to the thermocouple, the thermopile is a bigger and thicker device and also has higher voltage output.

Working of Thermopile

Now that the voltage output of a single thermoelectric cell is very tiny, many of these cells are arranged in the series so that a larger signal output can be achieved. This thermocouple stack arrangement is further referred to as thermopile.

It is the thermoelectric effect principle based on which thermopile works. The thermoelectric effect is explained as the direct conversion of temperature differences to electrical voltage and vice versa.

Whenever the dissimilar metals of the thermopile are exposed to temperature differences, a voltage is generated in it. With the addition of more pairs of thermocouples in a series to form the thermopile, the voltage output also increases.

Thermopile Connections

A few thermocouples are linked in a chain to form a thermopile. The two top thermocouples are a connected junction at the temperature T1 and the two bottom thermocouple junctions are at temperature T2.

The output voltage from the delta-V thermopile is directly proportional to the difference in the temperatures (T1 – T2), across the number of pairs of thermocouple junctions and the thermal resistance layer.

Thermopile Sensor

The thermopile sensor is the sensor device that uses non-contact-based temperature sensing with the help of thermocouples. These sensors have more voltage output compared to the conventional thermocouple sensors. The concept of infrared radiation absorption from the object being measured is used by the thermopile sensor device. The electrical output of this particular sensor is proportional to its temperature. Therefore, it is also referred to as a thermoelectric transducer.

Application of Thermopiles

The following mentioned are applications of thermopiles:

  • Non-contact measurement of temperature
  • Scanner Thermal Line
  • Human presence and identification for the protection of individuals
  • Monitoring blood glucose
  • Detecting flame and fire in the aircraft
  • Detecting fire in transit tunnels
  • Analyzing the automatic exhaust gas


Now that thermopile sensors are a great device to measure the temperature for both homes and commercial buildings, it is essential to learn about their working of the same. An individual looking forward to understanding the concept of thermopile must consider going through this thermopile module. This article will help in understanding the thermopile, its working, sensors, and applications.

Comments are closed.