AWWA DSS65662

Hydro-pneumatic tank systems are a tried and true system for providing pressure control and stabilization in smaller water distribution systems. The function and design of these systems are discussed in this paper. However, an alternative to the hydro-pneumatic tank is the use of variable frequency [speed] drive (VFD). The features and abilities of a VFD as a viable alternative to hydro-pneumatic tanks will be compared. An engineering evaluation on the basis of a previously designed and constructed (confidential client) system will be completed to make this comparison, and will include operation, maintenance, and capital costs. It is important to note that, in the context of this analysis, the hydro-pneumatic tank is a pressure maintenance/control device and not a surge tank. Surge control considerations are a critical issue in many pumping system designs. The hydro-pneumatic tank design can also be used for surge control but the system-specific surge control requirements must carefully be coordinated with the pressure control strategy, the primary function of the hydro-pneumatic tank used in this analysis. Includes 3 references, tables, figures.