Operating Options for Pumped Equalizing Storage

Abstract

There are two basic ways in which equalizing storage can be used by the operator of a service district with a pumped supply. Either the storage is unregulated and “floats” on the system for an extended period of time, or the storage is replenished, perhaps once each day, by manipulating the pumping schedule. This article discusses a hypothetical system comprised of a single pumped sendout, a distribution network, a single elevated storage site, and a constant‐suction water level. The pump shutoff and design heads, the volume, and the total depth and height of elevated storage have been held constant. Essentially, the pump design capacity was investigated to determine the effect of its quantity on recoverability of equalizing storage. Two operating options were considered: full daily recovery of storage by using higher‐capacity pumps; and, full recovery over about half of the year using a lower‐capacity pump, permitting the storage to float on the system. In the example presented, the annual power cost for the former appears to be 8 per cent higher. The range of pumping rates is greater, and the volume of storage utilized is less, for the daily full‐recovery option.

Ground Storage Booster Pumping Hydraulics

“…The head loss across the network between the master pump and the booster pump was represented by: 2:h = Qd"'q, ( <; r (3) in which '"i,h is the head loss in feet, Qa is the network customer demand in Qd"'cf> ( <;) n = head loss between master pumping station and booster pumping station (ft); q" m, and n are constants exponent for network pipe head loss relation, h = kpQ"', in which h is a branch head loss, Q the flow in the branch, and kp is the pipe coefficient accounting for length, diameter, friction coefficient, and units master pump design capacity (mgd) (Qvdm = Qd in this study) booster pump design capacity (rngd) (Qpelb = Ba in this study) Qpelb, ratio of booster pump design capacity to equivalent sinusoidal amplitude of a demand schedule master pump total dynamic head (ft) booster pump total dynamic head (ft) master pump design total dynamic head (ft) booster pump design total dynamic head (ft) For proportional loading, all local demands are assumed to change in direct proportion to the total service district demand.…”