| 摘要 |
An energy storage system is described that includes at least one body (10; 10') that is arranged to move along a bore (110; 110') that is excavated underground. The energy storage system includes a seal assembly within the bore (110; 110'). The seal assembly(19, 27;19',27') includes a support member (19; 19') and a seal element (27; 27'). The support member is arranged to support the body (10; 10') for movement in two directions within the bore (110; 10') and the seal element (27; 27') is adapted to isolate two regions within the bore (110; 110') from each other. The system(100; 100')also includes a fluid loading system wherein a first fluid (5; 5') and a second fluid (12; 12') can be separately fed to the bore (110; 110'). The first fluid (5; 5') is arranged in use to apply pressure to a first face of the seal element (27; 27') to 10 charge the energy storage system (100; 100'). The second fluid (12; 12') is of heavier density than the first fluid (5; 5') and is arranged to apply pressure to a second face of the seal element (27; 27'). The fluid loading system can control levels of the second fluid (12; 12') within the bore such that when the seal assembly (19, 27;19',27') is moved to charge or discharge the system, the pressure difference on the seal (27,27')element is reduced, thus enabling a more 1 moderate seal element (27,27') to be used, which minimises friction losses between the seal (27,27') and a wall of the bore 110. |
