Ultra-low temperature equipment generally refers to a refrigerator or freezer at -86℃. At present, this kind of temperature refrigeration system is divided into two types, one is double compressor cascade refrigeration, and the other is single compressor cascade refrigeration. Therefore, you can also choose equipment with single compressor automatic cascade cycle technology. Multi-stage cascade refrigeration means that the high temperature compressor is connected with the low temperature compressor to realize a complete temperature refrigeration cycle. This is a more traditional technology. Its advantages are mature and stable technology. The disadvantage is that when the equipment is aging, if one compressor is damaged and the other compressor fails to work, the whole equipment will suddenly stop, and the stored items are easily damaged due to long maintenance cycle (refer to Haier). The technology of single compressor automatic cascade system, that is, a compressor directly outputs the temperature of -86℃ by self-pressurization twice, has the advantages of simple design of refrigeration cycle path, fast cycle speed and rapid cooling, but the disadvantage is that the temperature stability of a single compressor is poor when it is cooled to -86℃. When the ambient temperature is higher than 28℃, a single compressor may not reach -80℃. In order to avoid this situation, two self-overlapping compressors are generally used to work independently, and both compressors output the temperature of -86℃, which can not only ensure that the temperature reaches -86℃ all the year round, but also make the other compressor circulate independently when the refrigerator is aging and the compressor fails, so as to avoid the refrigerator from stopping at once and damaging the stored items (refer to Collingway).
Summary: multistage cascade refrigeration cycle is the representative of traditional technology, such as manual transmission car; Single-machine automatic cascade technology represents more advanced international technology, such as automatic vehicles.
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