Compared to reciprocating refrigeration compressors, centrifugal refrigeration compressors have the following advantages:
They have a large single-unit cooling capacity; for the same cooling capacity, they are smaller in volume, occupy less space, and weigh 5 to 8 times less than reciprocating compressors.
Because they lack easily worn parts such as valves and piston rings, and do not have a crank-connecting rod mechanism, they are reliable in operation, run smoothly, produce less noise, are easy to operate, and have low maintenance costs.
There is no friction between the impeller and the casing, so lubrication is not required. Therefore, the refrigerant vapor does not come into contact with the lubricating oil, which improves the heat transfer performance of the evaporator and condenser.
The cooling capacity can be adjusted economically and conveniently, and the adjustment range is large.
However, they have poor adaptability to refrigerants; a centrifugal refrigeration compressor with a fixed structure can only be adapted to one type of refrigerant.
Because they are suitable for refrigerants with relatively large molecular weights, they are only suitable for large cooling capacities, generally above 250,000 to 300,000 kcal/hour. If the cooling capacity is too small, it requires a small flow rate and narrow flow channels, resulting in high flow resistance and low efficiency. However, in recent years, through continuous improvements, centrifugal refrigeration compressors used in air conditioning can have a single-unit cooling capacity as low as around 100,000 kcal/hour.