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.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to and the benefit of German Application No. DE 102013210430.8 filed Jun. 5, 2013, incorporated by reference herein in its entirety.FIELD OF INVENTION[0002]The present invention relates to an energy storage apparatus for the storage of thermal energy, with a charging and a discharge circuit, said apparatus being suitable for preheating feed water in a water / steam circuit. Energy storage apparatuses of this type are preferably integrated into power plants.BACKGROUND OF INVENTION[0003]Since electrical energy is increasingly being fed into the current distribution networks from renewable energy sources, there is a growing need to be able to store electrical energy intermediately for a period of time. The aim in this case is to have the ability, in the event of a surplus, to extract the electrical energy from the current distribution networks and make it available to the current distribution networks once agai...

AI Technical Summary

Benefits of technology

[0024]According to a further especially preferred embodiment, there is provision whereby, furthermore, a steam turbine plant capable of being operated by steam from the water / steam circuit is inserted into the discharge circuit. This steam turbine plant ensures the reverse conversion of thermal energy for the provision of electrical energy and is located in many power plants already installed. Consequently, by simple structural changes, an already existing power plant can be reequipped so that it can also utilize heat from the heat store suitably for the thermal conditioning of feed water.

Problems solved by technology

The disadvantage of this technical solution known from the prior art, however, is that the temperature which may prevail in the heat store is in most cases not sufficiently high to provide steam in the water / steam circuit in an operating state which is typical in a power plant.

The compression temperatures in this case occurring typically amount to not appreciably more than 300° C. However, the provision of steam at this temperature level necessitates a very high heat transmission rate of heat from the heat store to the water in the water / steam circuit.

However, efficient heat transmission for steam provision is thereby possible to only an inadequate extent, since the water quantities conducted in the water / steam circuit are very high.

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