In a carbon dioxide system, what type of oil system is usually used for vertical compressors?

In a carbon dioxide system, a splash system is commonly utilized for vertical compressors due to its operational characteristics and the specific requirements of CO2 as a refrigerant.

A splash lubrication system involves the use of an oil reservoir where the oil is splashed onto the moving parts, providing lubrication as the compressor operates. This method is particularly effective in vertical compressors because the vertical orientation allows for more efficient oil distribution through natural gravitational flow.

Carbon dioxide operates at high pressures and can create conditions in which other lubrication methods might not provide adequate coverage or could lead to oil starvation. The splash system is simple, reliable, and sufficiently effective under the high pressure conditions typically encountered in a CO2 refrigeration cycle.

Utilizing a splash system also helps in managing the potential for oil migration away from the compressor components, as the oil reservoir is generally located lower than the compressor elements, allowing for good coverage during startup and operation. This ensures that the moving parts receive the necessary lubrication to reduce wear and maintain efficiency over time.