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28 June 2022
Column for Ch & K Magazine: Is a refrigeration compressor like a car engine?


It is often said that a refrigeration compressor works in a similar way to an internal combustion engine … just the opposite. So let’s compare how a refrigeration compressor resembles a typical car engine.

One of the basic parameters of an internal combustion engine is its displacement volume. So what is the volume of the compressors we use? The smallest transcritical Bitzer 2NSL-05K has a volumetric capacity of 1.33 m3 / h, which gives a displacement volume of only 0.02 liters. The largest currently commercially available compressor – the 6-cylinder Dorin has a displacement of 99.6 m3 / h and a displacement of 1.15 liters. So at the level of a small city car. I remember that this manufacturer sometimes referred to automotive inspiration. This compressor has a capacity of 100 hp.

However, we also have sports engines – high-speed and more working, trucks – low-rev. The difference is, among other things, the proportion of the width of the piston to its stroke. The smaller the stroke, the higher the RPM, but the lower the torque. From my observations, most modern transcritical CO2 compressors have a stroke nearly twice as small as the diameter.

Therefore, if you want to treat the compressor and the internal combustion engine analogously, you should say that the compressor is something like an engine in a sports motorcycle: somewhere between a scooter and a sports 600.

I wonder if this is what the producers are inspired by?

This type of comparison could be made further and further, but now I invite the reader to the completely substantive part of our R744 section.


Maurycy Szwajkajzer

for the Chłodnictwo i Klimatyzacja magazine