Semiconductor chiller, also called thermoelectric chiller, is a type of heat pump. It has the advantage of no sliding parts, used in some space constraints, high reliability requirements, no refrigerant contamination. Using the Peltier effect (second hot spot effect) of semiconductor materials, when the DC current passes through the electric couple formed by two different semiconductor materials in series, the two ends of the electric couple can respectively absorb heat and release heat, which can achieve the purpose of refrigeration. It is a negative thermal resistance of the refrigeration technology, its characteristics are no moving parts, and relatively high reliability.

N-type semiconductor:

Every substance is made up of atoms, which are made up of nuclei and electrons. Electricity moves around the nucleus at a high speed and is attracted to the nucleus. Due to certain constraints, electrons can only move in a limited orbit and cannot leave at will. Electrons in each orbital have different energies (electron potential energy). The electrons in the farthest orbital from the nucleus can often escape the nucleus attraction and move between atoms, called conductors. If electrons can't get out of orbit to form free electrons, so they can't participate in conducting electricity, called an insulator. Semiconductor conductive ability between conductor and insulator, called semiconductor. The important characteristic of semiconductor is that after a certain amount of a certain impurity penetrates into the semiconductor, it can not only greatly increase the conductivity, but also make different properties and different uses of semiconductor according to the type and amount of impurities. When an impurity is mixed into a semiconductor, free electrons are released. This type of semiconductor is called an N-type semiconductor

P type semiconductor

Using "holes" to conduct electricity. Under the action of external electric field, the "hole" flow direction is opposite to the electron flow direction, that is, the "hole" flows from the positive plate to the negative electrode, which is the P-type semiconductor principle.

Carrier phenomenon

The free electrons in N-type semiconductors and the "holes" in P-type semiconductors are all involved in conducting electricity, collectively known as "charge carriers", which are unique to semiconductors as a result of incorporation of impurities.

Semiconductor refrigeration

Not only are N-type and P-type semiconductor characteristics required, but also the temperature difference electromotive force rate, electrical conductivity and thermal conductivity of the semiconductor are changed according to the impurities incorporated so that this particular semiconductor can meet the requirements of refrigeration materials. At present, bismuth telluride based ternary solid solution alloy is commonly used in China. P-type is Bi2Te3 -- Sb2Te3, N-type is Bi2Te3 -- Bi2Se3, and the crystal material is extracted by vertical zone melting method.

Advantages of semiconductor refrigeration technology

As long as the semiconductor refrigeration sheet is used as a special cold source, it has obvious advantages and characteristics in the technical application:

01 Green Environmental Protection

No refrigerant required, no source of pollution; Continuous work, no rotating parts, no rotation effect, no sliding parts, is a solid piece;

02 No Noise

Different from traditional mechanical refrigeration devices, thermoelectric refrigerators do not produce any electronic interference signals in the process of operation, it can be connected with sensitive electronic sensors, will not interfere with its work. In addition, it does not make any noise during operation;

Fast switching between cooling and heating

Semiconductor refrigeration sheet has two functions, both refrigeration and heating, and refrigeration and heating can be quickly switched, so the use of a piece can replace the separate heating system and refrigeration system.

Precise temperature control

Semiconductor refrigeration sheet is a current energy exchange type sheet, through the input current control, can achieve accurate temperature control in the range of 0.1 ℃. Coupled with temperature detection and control means, it is easy to achieve remote control, program control, computer control, easy to form automatic control system.

05 High Reliability

Thermoelectric refrigeration appliances have high reliability due to their solid - state - based construction. Although to some extent dependent on the conditions of application, the life of a typical thermoelectric cooler can generally reach more than 200,000 hours.

06 Lower the temperature below the ambient temperature

Unlike traditional radiators, which need to be raised above the ambient temperature to be used, thermoelectric refrigerators have the ability to reduce the temperature of objects below the ambient temperature. One of the most important is the application of ceramic substrates, which are resistant to high temperatures and can dissipate heat quickly.

07 Reverse temperature difference power generation

The reverse use of semiconductor refrigeration is thermal power generation, semiconductor refrigeration is generally suitable for low - and medium-temperature region power generation.

Both alumina ceramic substrate and aluminum nitride ceramic substrate are widely used in semiconductor refrigeration, the use of ceramic substrate can realize the rapid cooling function of the refrigeration sheet. The advantages of ceramic circuit board also retain the characteristics of its material, and unlike traditional PCB need to use insulating medium as an insulating layer, ceramic itself is an insulating layer. It also has high frequency and low dielectric constant, because the manufacturing process is easier in terms of light, thin and miniaturization. Because of its high thermal conductivity, good chemical stability, thermal stability and high melting point, ceramic materials are very suitable for making circuit boards used in the field of electronics.