Peltier thermoelectric heat pump

Values of pyroelectric coefficient are calculated from equation (l),by measuring the pyroelectric current for a known controlled temperature profile. A computer-controlled system has been developed, to force the temperature of a sample under test, and log the corresponding pyroelectric current. This system is shown schematically in figure 2. Samples are mounted in an earthed vacuum chamber. Evacuation of the sample chamber removes a significant proportion of absorbed water, which is otherwise responsible for spurious, thermally induced currents. The temperature of the sample is controlled,in both heating and cooling, by a Peltier thermoelectric heat pump. 

Some heat pumps, called thermoelectric heat pumps, employ the Peltier effect, using thermocouples. The Peltier effect refers to the evolution or absorption of heat produced by an electric current passing across junctions of two suitable, dissimilar metals, alloys, or semiconductors. Presently, thermoelectric heat pumps are used only in some specialized applications. They have not been developed to a point to make them practical for general heating and cooling of buildings. 

Wittbrodt, J. and W. Erhardt. An inexpensive and versatile computer-controlled PCRmachine using a Peltier element as a thermoelectric heat pump. Trends Genet. 1989, 5(7), 202-203... 

The effectiveness of devices using thermoelectric effects depends on the magnitude of the relative Peltier coefficient, II, or its equivalent, the relative Seebeck coefficient, S. However, these are not the only material parameters of importance. As an example, consider the operation of a heat pump. The amount of heat produced or absorbed is... 

Thermoelectric (TE) modules are solid-state heat pumps that operate on the Peltier effect [1]. A TE module consists of an array of p- and n- type semiconductor elements heavily doped with electrical carriers. The array of elements is soldered so that it is electrically connected in series and thermally connected in parallel [1 ]. This array is then often affixed to two ceramic substrates (insulators), one on each side of the elements as seen in Figure 1. 

Thermoelectric coolers (TEC) are solid-state heat pumps based upon the Peltier effect without any fluids or moving mechanical parts. In the Peltier effect, a potential is applied to two junctions as shown in Figure 3.15. Heat will be expelled from one junction and absorbed into the other in an amount proportional to the applied current. The thermoelectric cooler consists of an array of junctions using bismuth telluride (Bi2Te3), lead telluride (PbTe), or silicon germanium (SiGe). These materials are doped during fabrication to optimize the parameters of the cooler. Bismuth telluride has been found to have the best performance and is widely used for thermoelectric coolers. 

Peltier effect A thermoelectric cooling effect used in small-scale refrigeration units. It involves a solid-state heat pump that transfers heat from one side of the device to the other through the consumption of electticity. The thermoelectric cooling effect is created between the junction of two different types of conducting materials. The device can also be used for heating. It is named after French physicist lean Charles Athanase Peltier (1785-1845) who discovered the effect in 1834. 

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