Peltier effect - electricity can make ice

In 1834, the French watchmaker and naturalist Jean-Charles Peltier, during his experiments, placed a drop of water between the electrodes of bismuth and antimony, and then passed an electric current through the circuit. To his amazement, he saw that the drop suddenly froze.

The thermal effect of electric current on conductors was known, but the opposite effect was akin to magic. You can understand Peltier's feelings: this phenomenon at the junction of two different areas of physics - thermodynamics and electricity - evokes a sense of miracle today.

How it works according to physicists: The reason for the occurrence of the Peltier phenomenon is as follows. At the contact of two substances there is a contact potential difference, which creates an internal contact field. If an electric current flows through the contact, then this field will either facilitate the passage of the current or prevent it. If the current goes against the contact field, then the external source must spend additional energy, which is released in the contact, which will lead to its heating. If the current flows in the direction of the contact field, then it can be supported by this field, which does the work of moving charges. The energy required for this is taken from the substance, which leads to its cooling at the point of contact.

Over time, this effect was forgotten, because they could not find a practical application for it and remembered about it only a century and a half later, during the development of electronics. At the moment, Peltier elements are being successfully implemented in many areas of activity:

Peltier elements are used in situations where cooling with a small temperature difference is required, or the energy efficiency of the chiller is not important. For example, Peltier elements are used in PCR amplifiers, small car refrigerators, since the use of a compressor in this case is impossible due to its limited size, and, in addition, the required cooling power is not high.

In addition, Peltier elements are used to cool CCD devices in digital cameras. Due to this, a noticeable reduction in thermal noise is achieved during long exposures (for example, in astrophotography).

Multistage Peltier elements are used to cool radiation receivers in infrared sensors.

Also, Peltier elements are often used for cooling and thermostating diode lasers in order to stabilize the radiation wavelength.

In appliances with low cooling capacities, Peltier elements are often used as a second or third stage of cooling. This makes it possible to achieve temperatures 30–40 K lower than with conventional compression coolers (up to –80 for one-stage refrigerators and up to –120 for two-stage refrigerators).

"Peltier Electric Generator" - a module for generating electricity, thermoelectric generator module, abbreviations GM, TGM. This thermogenerator consists of two main parts: it is a direct converter of the temperature difference into electricity on the Peltier module.