Thermal energy storage and recovery system comprising a storage arrangement and a charging/discharging arrangement being connected via a heat exchanger

Abstract

A thermal energy storage and recovery system including a storage arrangement having a thermal energy storage device for temporarily storing thermal energy, a charging/discharging arrangement having a fluid energy machine for exchanging mechanical work with a working fluid cycling through the charging/discharging arrangement, and a heat exchanger which is arranged between the storage arrangement and the charging/discharging arrangement and which thermodynamically couples a heat transfer fluid cycling through the storage arrangement with the working fluid is provided. The storage arrangement is configured in such a manner that the heat transfer fluid is under a first pressure and the charging/discharging arrangement is configured in such a manner that the working fluid is at least partially under a second pressure, wherein the second pressure is higher than the first pressure.

We claim: 
     
         1 . A thermal energy storage and recovery system comprising
 a storage arrangement having a thermal energy storage device for temporarily storing thermal energy;   a charging/discharging arrangement having a fluid energy machine for exchanging mechanical work with a working fluid cycling through the charging/discharging arrangement; and   a heat exchanger arranged between the storage arrangement and the charging/discharging arrangement and thermodynamically couples a heat transfer fluid cycling through the storage arrangement with the working fluid,   wherein the storage arrangement is configured in such a manner that the heat transfer fluid is under a first pressure,   wherein the charging/discharging arrangement is configured in such a manner that the working fluid is under a second pressure, and   wherein the second pressure is higher than the first pressure.   
     
     
         2 . The thermal energy storage and recovery system as claimed in  claim 1 , wherein the first pressure is an ambient pressure of the thermal energy storage and recovery system. 
     
     
         3 . The thermal energy storage and recovery system as claimed in  claim 1 , wherein the storage arrangement comprises means for driving a flow of heat transfer fluid through the storage arrangement. 
     
     
         4 . The thermal energy storage and recovery system as claimed in  claim 1 ,
 wherein in a first operational mode, in which the thermal energy storage device receives thermal energy from the heat transfer fluid, the storage arrangement is configured for circulating the heat transfer fluid in a first direction, and   wherein in a second operational mode, in which the thermal energy storage device transfers thermal energy to the heat transfer fluid, the storage arrangement is configured for circulating the heat transfer fluid in a second direction being opposite to the first direction.   
     
     
         5 . The thermal energy storage and recovery system as claimed in  claim 4 ,
 wherein in the first operational mode the charging/discharging arrangement is configured for circulating the working fluid in a further first direction, and   wherein in the second operational mode the charging/discharging arrangement is configured for circulating the working fluid in a further second direction being opposite to the first direction.   
     
     
         6 . The thermal energy storage and recovery system as claimed in  claim 4 ,
 wherein the charging/discharging arrangement further comprises a further fluid energy machine, and   wherein with respect to a flow direction of the working fluid the fluid energy machine is located upstream of the heat exchanger and the further fluid energy machine is located downstream of the heat exchanger.   
     
     
         7 . The thermal energy storage and recovery system as claimed in  claim 6 ,
 wherein the fluid energy machine and the further fluid energy machine are configured such that in the first operational mode, the fluid energy machine generates thermal energy for the heat exchanger and the further fluid energy machine receives thermal energy from the heat exchanger, whereby the generated thermal energy is larger than the received thermal energy, and   wherein the fluid energy machine and the further fluid energy machine are configured such that in the second operational mode, the fluid energy machine receives thermal energy from the heat exchanger and the further fluid energy machine generates thermal energy for the heat exchanger, whereby the received thermal energy is larger than the generated thermal energy.   
     
     
         8 . The thermal energy storage and recovery system as claimed in  claim 7 ,
 wherein the charging/discharging arrangement further comprises a mechanical energy transmission arrangement, which is connected between the fluid energy machine and the further fluid energy machine, and   wherein the mechanical energy transmission arrangement is configured for directly exchanging mechanical energy between the fluid energy machine and the further fluid energy machine.   
     
     
         9 . The thermal energy storage and recovery system as claimed in  claim 8 ,
 wherein in the first operational mode the further fluid energy machine is configured for producing cold when expanding the working fluid, and   wherein the produced cold is useable for cooling purposes.   
     
     
         10 . The thermal energy storage and recovery system as claimed in  claim 1 , wherein the charging/discharging arrangement is configured in such a manner that the working fluid when circulating through the charging/discharging arrangement undergoes a change of its state of aggregation. 
     
     
         11 . The thermal energy storage and recovery system as claimed in  claim 10 , wherein the charging/discharging arrangement is configured in such a manner that in the first operational mode the charging/discharging arrangement is configured for acting as a heat pump and in the second operational mode the working fluid within the charging/discharging arrangement undergoes a steam cycle. 
     
     
         12 . The thermal energy storage and recovery system as claimed in  claim 1 ,
 wherein the thermal energy storage device comprises a container having a first fluid terminal for inserting the heat transfer fluid into the interior of the container and a second fluid terminal for extracting the heat transfer medium from the interior of the container and a heat storage material accommodated within the container, and   wherein the heat storage material is spatially arranged within the container in such a manner that heat transfer fluid flowing between the first fluid terminal and the second fluid terminal gets into direct physical contact with the accommodated heat storage material.   
     
     
         13 . The thermal energy storage and recovery system as claimed in  claim 12 , wherein the heat storage material comprises rock material and/or sand material. 
     
     
         14 . The thermal energy storage and recovery system as claimed in  claim 13 , wherein the heat storage material comprises concrete. 
     
     
         15 . The thermal energy storage and recovery system as claimed in  claim 1 , wherein the heat transfer fluid and/or the working fluid is a gas. 
     
     
         16 . The thermal energy storage and recovery system as claimed in  claim 15 , wherein the working gas is air.