| 摘要 |
An energy storage system includes at least one body that is arranged to move along a bore that is excavated underground. The energy storage system includes a seal assembly within the bore. The seal assembly includes a support member and a seal element. The support member is arranged to support the body for movement in two directions within the bore and the seal element is adapted to isolate two regions within the bore from each other. The system also includes a fluid loading system wherein a first fluid and a second fluid can be separately fed to the bore. The first fluid is arranged in use to apply pressure to a first face of the seal element to charge the energy storage system. The second fluid is of heavier density than the first fluid and is arranged to apply pressure to a second face of the seal element. The fluid loading system can control levels of the second fluid within the bore such that when the seal assembly is moved to charge or discharge the system, the pressure difference on the seal element is reduced, thus enabling a more moderate seal element to be used, which minimises friction losses between the seal and a wall of the bore. |
