Steam accumulator


A steam accumulator is an insulated steel pressure tank containing hot water and steam under pressure. It is a type of energy storage device. It can be used to smooth out peaks and troughs in demand for steam. Steam accumulators may take on a significance for energy storage in solar thermal energy projects. An example is the PS10 solar power tower plant near Seville, Spain and one planned for the "solar steam train" project in Sacramento, California.
Estate, Pimlico, London, United Kingdom. This plant once used waste heat piped from Battersea Power Station on the opposite side of the River Thames.

History

It was invented in 1874 by the Scottish engineer Andrew Betts Brown.

Charge

The tank is about half-filled with cold water and steam is blown in from a boiler via a perforated pipe near the bottom of the drum. Some of the steam condenses and heats the water. The remainder fills the space above the water level. When the accumulator is fully charged the condensed steam will have raised the water level in the drum to about three-quarters full and the temperature and pressure will also have risen.

Discharge

Steam can be drawn off as required, either for driving a steam turbine or for process purposes, by opening a steam valve on top of the drum. The pressure in the drum will fall but the reduced pressure causes more water to boil and the accumulator can go on supplying steam for some time before it has to be re-charged.

Pressure and temperature

This steam table shows the relationship between pressure and temperature in a boiler or steam accumulator:
Gauge pressure, PSI Absolute pressure, PSI Temperature, °F
0 15 212
35 50 281
85 100 328
135 150 358
185 200 382
235 250 401

Abbreviations and notes