Energy storage apparatus for the preheating of feed water

Abstract

An energy storage apparatus for the storage of thermal energy is provided, with a charging circuit, having a compressor, a heat store and an expansion turbine, the compressor connected on the outlet side to the inlet of the expansion turbine via a first line for a first working gas, and the heat store inserted into a second line, and the first line connected to a first heat exchanger, in which the first line and the second line are coupled thermally, and, furthermore, having a discharge circuit which has a water/steam circuit equipped with a steam generator and which has at least one feed water preheater preceding the steam generator with respect to the direction of flow of the water in this water/steam circuit, and thermal coupling between the charging circuit and discharge circuit achieved by the feed water preheater, in particular achieved solely by the feed water preheater.

1 . An energy storage apparatus for the storage of thermal energy, with a charging circuit, comprising
 a compressor, a heat store and an expansion turbine, the compressor being connected on the outlet side to the inlet of the expansion turbine via a first line for a first working gas, and the heat store being inserted into a second line , and the first line being connected to a first heat exchanger, by which the first line and the second line are coupled thermally, and,   a discharge circuit which comprises a water/steam circuit which is equipped with a steam generator and which has at least one feed water preheater preceding the steam generator with respect to the direction of flow of the water in this water/steam circuit, wherein thermal coupling between the charging circuit and discharge circuit being achieved by the feed water preheater.   
     
     
         2 . The energy storage apparatus as claimed in  claim 1 , wherein the feed water preheater is designed as a heat exchanger which is likewise coupled thermally to a low-temperature steam line. 
     
     
         3 . The energy storage apparatus as claimed in  claim 1 , wherein the feed water preheater is designed as a heat exchanger which is likewise coupled thermally to a medium-temperature steam line. 
     
     
         4 . The energy storage apparatus as claimed in  claim 1 , wherein the feed water preheater is designed as a heat exchanger which is likewise coupled thermally to a high-temperature steam line. 
     
     
         5 . The energy storage apparatus as claimed in  claim 1 , wherein the feed water preheater comprises at least two, heat exchangers which are in each case connected thermally to a steam line which can transmit heat at a different temperature level. 
     
     
         6 . The energy storage apparatus as claimed in  claim 1 , wherein the compressor and the expansion turbine are arranged on a common shaft. 
     
     
         7 . The energy storage apparatus as claimed in  claim 1 , wherein the compressor and the expansion turbine are arranged so as to be decoupled mechanically from one another. 
     
     
         8 . The energy storage apparatus as claimed in  claim 1 , wherein the compressor and the expansion turbine are connected via an essentially closed line circuit for the first working gas which comprises the first line. 
     
     
         9 . The energy storage apparatus as claimed in  claim 1 , wherein the first line comprises an electrically operated heating device. 
     
     
         10 . The energy storage apparatus as claimed in  claim 1 , wherein additional electrical heating is inserted into the charging circuit upstream of the heat store. 
     
     
         11 . The energy storage apparatus as claimed in  claim 1 , wherein the heat store contains a porous storage medium which comprises sand, gravel, rock, concrete, water, salt and/or thermal oil. 
     
     
         12 . The energy storage apparatus as claimed in  claim 1 , further comprising, a steam turbine plant capable of being operated by steam from the water/steam circuit inserted into the discharge circuit. 
     
     
         13 . The energy storage apparatus as claimed in  claim 1 , wherein thermal coupling between the charging circuit and discharge circuit is achieved solely by the feed water preheater. 
     
     
         14 . The energy storage apparatus as claimed in  claim 2 , wherein the low-temperature steam line emanates from a low-pressure steam part of a steam turbine connected to the water/steam circuit. 
     
     
         15 . The energy storage apparatus as claimed in  claim 3 , wherein the medium-temperature steam line emanates from a medium-pressure steam part of a steam turbine connected to the water/steam circuit. 
     
     
         16 . The energy storage apparatus as claimed in  claim 4 , wherein the high-temperature steam line emanates from a high-pressure steam part of a steam turbine connected to the water/steam circuit. 
     
     
         17 . The energy storage apparatus as claimed in  claim 5 , wherein the feed water preheater comprises exactly two heat exchangers which are in each case connected thermally to a steam line which can transmit heat at a different temperature level.