Industrial cooling and refrigeration systems can consume a lot of energy, not least because they often run continuously. Screw and reciprocating compressors also need high overload capabilities. A variable-speed drive (VSD) is a natural fit for these applications because drives can reduce energy usage significantly throughout their lifetime, allow better control over temperature to reflect needs at a given time, and reduce equipment wear.

Here are three things to bear in mind when installing, replacing or upgrading drives for refrigeration applications:

Understand the compressor’s overload requirements Depending on the type of compressor, overload requirements may be much higher than for other applications. Compressing air needs a lot of mechanical inertia, and thus a high starting current. This has implications for the kind of drive to use, because the overload requirement can be up to 160%. In some cases, this will require a heavy-duty drive. Many general-purpose drives (such as ABB’s ACS580) will have heavy- and normal-duty ratings, however you may still need to oversize your drive to handle both the application’s power requirement and the overload current. For example, an 11kW compressor application with 160% overload will require a drive rated at 30kW or more.

Check mechanical infrastructure Before the advent of VSDs, cooling power was controlled using valves, louvres and dampers. A VSD can instead provide constant and precise pressure and flow control automatically, regardless of the conditions, and without the need for any mechanical vents or other devices. After a drive has been installed, these mechanical items are sometimes not only left in place, but left fully or partially open/closed. This is extremely inefficient, because everything a damper is stopping, and/or anything that is escaping through a vent, is simply wasted energy. After installing a drive, check the mechanical infrastructure and fully open/close, or remove, any unnecessary mechanical controls to allow the drive to operate with maximum efficiency.

Use a trusted provider For the reasons outlined above, and many others, refrigeration is not like other applications. To achieve the best outcome for your facility, you need to work with a service provider, installer or OEM who has knowledge and experience of the F&B industry, as well as compressor drive requirements, where drives should be installed, and how they should be used.