EPAnet/Hydroneumatic Tank

[Peak10]

First timer here and looking forward to all the great insite. I am currently learning the process it takes to set up a water distribution model in EPAnet. I have a solid understanding of most things with this program but I am having difficulties modeling a Hydroneumatic Tank. I am currently using a elevated storage tank to represent the Hydroneumatic Tank since the elevated storage tank allows me to apply an initial, min and max level (or in other words a certain pressure or head). In the specs they call out that the design pressure on site is 55 psi, therefore I have converted this to head (127.05 ft.) and used that as my "initial" level in the storage tank. I have also set my pumps to turn ON if the Hydroneumatic Tank initial level drops below the 127.05 ft, that way my Tank/site maintains a pressure of 55 psi. Is this the best way to do this and does it correctly represent the way a Hydroneumatic Tank works?

Thanks

 

[hydrae]

A hydro tank can be simulated by a tall and very skinny tank that gets skinnier as it rises in elevation, you can do this with a tank curve, in the curves section.
This is because it will take less gallons to raise the pressure a set value in the top end as it does as the tank level is lower. Although this can be considered polishing the cannonball. More polishing, if you consider the temperature of the air in the tank to be adiabatic or isothermal, most likey someplace in between, Isothermal is easier (p*v = const)

I would also base the pump 'call' on the actual pressure switch location, since there may be some distance between the hydro tank and the pump, again polishing.

Hydrae