Tandem compressors
prices on 5 models— devices created according to the "tandem" scheme are actually two compressors on one receiver, connected in parallel. This allows you to turn on both compressors at once, or only one of them — in this way you can adjust the power and performance even in those models where special regulators such as a frequency converter (see the relevant paragraph) are not provided at all.
Among the disadvantages are heavy weight, bulkiness and high cost. In addition, the tandem scheme of operation is mainly suitable for powerful performant units — otherwise the individual compressors would have to be made too small, and this does not make sense.