Originally posted by ANIL:
Can some body explain the functioning and advantages of hydro pneumatic systems?
In theory you cannot compress water so by using a small air compressor connected to a tank you can boost water pressure by using compressed air to push the water as a valve is opened.
You would set a high limit switch to cut the air compressor off at so many PSI and a low pressure switch to increase the pressure as water is drawn off. Called cut in and cut out differentials.
Personally I do not like this type of system on large residential buildings or commercial work, as during peak hours the water system may lack enough volume to maintain proper pressure for some of the applications needed.
On fire suppression systems I find this is the easiest way to boost the pressure for stand piping and sprinklers as the sprinkler/stand pipe system very seldom looses pressure and this system just maintains the system to the proper setting.
The advantage of a hydro pneumatic system is no need for a roof tank and there is some room for error in designing this type of system.
The major disadvantage is there are several mechanical/electrical components that can fail.
You can also play games with a system like this by having city pressure take care of the lower floors and this pressure system handling the upper floors.
A favorite installation (on taller structures) is also a pumped gravity feed system where you use the pump pressure to reach the upper floors and let gravity down feed the cold and hot water lines.
What you do is boost the pressure through a tankless coil and then feed up thirty or more floors and let the water down feed through larger risers.
A major disadvantage is there is very little reserve time in case of a black out if the pump goes down.
If you send me an E mail ILL be able to elaborate on a much simpler system that is really cost effective and gives lots of reserve for stand pipe piping and domestic water supplies and is very cost effective.
One of the easiest to maintain.
Here is a link to an article that has a picture of a good pump design.
Good luck.. Again any questions please feel free to E mail me