System for storing and outputting thermal energy and method for operating said system

Abstract

A system for storing and outputting thermal energy and a method for operating the system are provided. The system operates according to the Brayton cycle, wherein a heat accumulator is charged by a compressor and a cold accumulator is charged by turbines. The cycle is reversed for discharging. In addition, the cold accumulator supplies a cooling circuit, which provides the cooling for a superconducting generator by a cooling unit. A favorable generator weight can thereby be advantageously achieved in particular for wind turbines, because the generators are limited regarding the weight thereof due to being housed in the nacelle of the wind power plant. Thus, advantageously higher power can be converted in the wind power plant.

1 . A plant for storing and releasing thermal energy, comprising:
 a charging circuit and a discharging circuit for a working gas, wherein in the charging circuit the following units are interconnected in the specified sequence by means of a line for the working gas:
 a first thermal fluid energy machine, 
 a heat accumulator, 
 a second thermal fluid energy machine, and 
 a cold accumulator, 
   wherein the first thermal fluid energy machine is operated as a working machine and the second thermal fluid energy machine is operated as a power machine, as seen in the flow direction of the working gas from the heat accumulator to the cold accumulator,   wherein the cold accumulator is adapted to be connected into a cooling circuit which is separated from the aforesaid circuits and in which the following units are interconnected in the specified sequence by means of a line for a cooling medium:
 the cold accumulator, 
 a cooling unit, and 
 a cold consumer which is to be cooled. 
   
     
     
         2 . The plant as claimed in  claim 1 , 
       wherein the cold consumer is an electric machine with superconducting components. 
     
     
         3 . The plant as claimed in  claim 2 , 
       wherein the electric machine is a generator. 
     
     
         4 . The plant as claimed in  claim 3 , 
       wherein the generator is installed in a wind power plant. 
     
     
         5 . The plant as claimed in  claim 2 , 
       wherein the electric machine is a motor which is mechanically coupled to the first thermal fluid energy machine. 
     
     
         6 . The plant as claimed in  claim 2 , 
       wherein the electric machine is a generator which is coupled
 to the first thermal fluid energy machine, or 
 to a third thermal fluid energy machine, 
 wherein the third thermal fluid energy machine is connected in parallel with the first thermal fluid energy machine and a fourth thermal fluid energy machine is connected in parallel with the second thermal fluid energy machine in the charging and discharging circuit, 
 wherein a valve mechanism is provided in each case between the first and the third thermal fluid energy machines and between the second and the fourth thermal fluid energy machines. 
 
     
     
         7 . The plant as claimed in  claim 2 , 
       wherein a high-temperature superconductor is used for the superconducting components. 
     
     
         8 . A method for storing and releasing thermal energy, comprising:
 passing a working gas through a charging circuit or a discharging circuit, wherein in the charging circuit flow passes through the following units in the specified sequence:
 a first thermal fluid energy machine, 
 a heat accumulator, 
 a second thermal fluid energy machine, and 
 a cold accumulator, 
   operating the first thermal fluid energy machine as a working machine and the second thermal fluid energy machine as a power machine,   connecting the cold accumulator, when required, into a cooling circuit which is separated from said circuits, wherein in the cooling circuit a cooling medium flows through the following units in the specified sequence:
 the cold accumulator, 
 a cooling unit, and 
 a cold consumer which is to be cooled. 
   
     
     
         9 . The method as claimed in  claim 8 , 
       wherein nitrogen is used as cooling medium. 
     
     
         10 . The plant as claimed in  claim 7 ,
 wherein Bi2223 or YBCO is used for the superconducting components.