A bit of theory
Peltier modules are used to create micro-cooling and micro-heating among other applications. Their work is based on the Peltier effect. Peltier effect which is a thermoelectric phenomenon explains that when a voltage is applied to two electrically connected dissimilar materials, depending on the direction of the current, heat will be created or absorbed. This effect is used to make what is called a Peltier cooler or heater or a Thermoelectric cooler (TEC). There are many materials for making thermoelectric devices.
A thermoelectric module consists of a semi-conductor array of p-and n-type elements extensively doped with electrical carriers. The components are arranged in an arrangement that is connected electrically in series and thermally in parallel. This array is then applied to two ceramic substrates, one on either side of the elements.
When a voltage is applied to the two semiconductors ‘ free ends, there is a stream of DC current across the semiconductor junction creating a difference in temperature. The cooling plate side absorbs heat that is then transferred to the other side of the device where a heat sink is placed. The overall unit’s cooling power is proportional to the number of TECs it comprises. By merely changing the way the current flows through the system, the cold junction and the warm junction can be reversed.
In applications involving heat removal from milliwatts to several thousand watts, Peltier modules are used. These can be made as compact as a beverage cooler or as big as a submarine for applications. For example, Peltier elements are widely found in consumer goods used for camping, portable coolers, electronic cooling components, and small tools.
Pros and cons of TEC application
Pros of Peltier modules include:
- relatively small total dimensions
- ability to work for both cooling and heating of the system
- lack of moving parts, structural elements, prone to wear
Cons of Peltier modules include:
- the need for a source of current for their operation;
- the capacity of high demand to achieve appreciable temperature variations and, as a result, significant thermal insulation;
- small measurements and useful characteristics.
Despite the negative features of the Peltier units, they have found their use in several products. TECs are useful in the first place where the cooler’s energy efficiency is uncritical, the smaller–the better Elements are used for cooling devices with charge contact in digital cameras enabling a noticeable reduction of thermal noise during long exposures. Peltier modules are often used for cooling or thermostatic diode lasers to control their radiation wavelengths. It is possible to use several TECs, arranged in series in the form of cascades (the cold side of one cools the warm side of the other) in such a manner that it is possible to achieve very low temperatures for low heat release products. Elements Peltier–the foundation of small refrigerators, mainly automotive.
What are the thermocouple elements?
The two semiconductors Bismuth and Telluride are the most common combination of materials in Peltier Thermocouples (TECs). Typically, the TEC has a variety of cubes or pellets made of semiconductors, each of which is in touch with the radiators on the hot and cold side of the Peltier component.
What is the difference between TEC and TEG(Thermo Electric Cooling & Thermo Electric Generator)
The thermoelectric effect is used by all device groups. This mechanism is reversible so that both types of modules can operate as a cooler or generator; if the voltage is applied to the module, the energy will be drained, but if the temperature differential is applied to the device, the voltage will be produced. It is still advised that cooler modules be used for heating and that generator modules be used for generating electricity. This is because the cooler and generator modules have been primarily designed for different temperature scales, with cooler modules more efficient at temperatures similar to room temperature, as is commonly found for colder systems, while generator modules are configured for higher temperatures. For a fact, depending on the device, generator modules can tolerate higher temperatures, for example by using specific solders. This is the distinction between the thermoelectric cooler module and a thermoelectric generator module.
When combining Peltier modules to various traditional cooling/heating systems, the Peltier module is better able to save energy. The output of a Peltier device can also be regulated by changing the voltage supply needed for human use. Peltier kits are less expensive and are therefore compact and user-friendly. They are environmentally friendly because they do not lead to any threats to the climate. While Peltier modules have a lower lifespan and performance, they overcome major weaknesses of most traditional heating/cooling systems, such as power consumption and portability, and the same system is capable of heating and cooling.