Which is better hydraulic or pneumatic and why?
Hydraulic and pneumatic systems can transport energy and do work, however the pneumatic system stores energy (compressed air) that can cause an explosive release if a system component such as a tank ruptures while pressure drops quickly if a hydraulic system ruptures. Pneumatic systems use fluids (gases) that are not as heavy as the liquids used in hydraulic systems. Hydraulic systems can provide better lubrication and heat removal (using heat exchangers) than pneumatic systems although oil can be added to pneumatic systems if it will not contaminate products, etc. Hydraulic fluids will not expand at elevated temperatures that do not vaporize the fluid unlike pneumatic systems where heat expands gas or increases its pressure.
