Mechanism itself is a pump with electric placed in a sealed enclosure. In other parts of his refrigerator connect two tubes – one hole for the suction or input, and another – an opening for discharge, or exit. Now equipped with refrigerators, one or two compressors. It depends on the model. You can not always detect the presence of two compressors in the refrigerator. Chambers-then maybe two, but with them calmly handle a cooling compressor. The problem is that this mechanism odnokompressornyh refrigerators are much more powerful and therefore may be noisier than any of his dvuhkompressornyh similar machines. But it all depends on the specific model and it is possible that after all two compressors will publish more noise than one. More information is housed here: Professor Roy Taylor. Advantage dvuhkompressornyh units that the user has the ability to independently set the temperature in the refrigerator and freezer. And if you decided to go somewhere, you can easily disable one of the chambers, leaving the work to another. Thus, you save electricity. With thermoelectric cooling current passes through thermoelectric elements. In During this process, the part of the thermoelectric plates, which are located inside the chamber is cooled. And those who are outside the chamber, are heated. That is, cooling is due to the semiconductor thermoelectric elements. But the refrigerator with the cooling, as a rule, small size, do not have the freezer and used in small offices, in cars, on boats and yachts. As already mentioned above, Most modern refrigerators cooling is carried out by means of compressors. Noise should probably raise the question of noise refrigerator. Noise level is measured in decibels (dB). The lower the value, the quieter work your refrigeration unit. On average, single-chamber refrigerator, the figure is 40-43 dB, and a two-chamber – 40-45 dB. In general, the noise that comes from the refrigerator while it is running, almost imperceptible to the ear.