RACKS or multicompressor sets usually consist of multiple compressors connected in parallel operation. They are equipped with a suction collectors and systems for active oil return in the compressor and the necessary electronics for operation of the device. RACKS are attractive devices, because condensers and evaporators are not installed on the set. This design allows that the RACKS is installed in a place where it does not take useful space and on the device can be connected more evaporators which are located in separate rooms.

RACKS cover a wide range of refrigeration capacity. A large number of possibilities for performance of these devices make them attractive for commercial refrigeration.
RACKS can be made without regulation capacity (on / off operation) and with the control capacity. For the step capacity control are used capacity control valves on the compressor head. Built-in electronics determines the mode of the device. For more precise capacity control is mounted frequency converter.
To easy start of the device it can be installed unloaded start valves. They not only make it easier to start the compressor, but also significantly reduce the start current of the compressor.