Compressed air energy storage power generation device

A compressed air energy storage power generation device comprising:

• a compressor/expander combined machine that is of displacement type and has a function as a compressor for compressing air and a function as an expander for expanding compressed air;
• a motor/generator combined machine that is mechanically connected to the compressor/expander combined machine and has a function as an electric motor for driving the compressor/expander combined machine and a function as a generator driven by the compressor/expander combined machine;
• and
• a pressure accumulator that is fluidly connected to the compressor/expander combined machine and stores compressed air generated by the compressor/expander combined machine, wherein
• the compressor/expander combined machine includes
• a first casing that defines a compression chamber and is provided with a first through hole,
• a first rotating shaft member that is inserted through the first through hole, and
• a first seal part that seals a gap between the first rotating shaft member and the first casing in the first through hole;
• and
• the first seal part includes
• a lubricant labyrinth seal having a rotationally axisymmetric shape so as not to depend on a rotation direction of the first rotating shaft member, and
• two or more of air ring seals disposed, in a direction in which the first rotating shaft member extends, closer to the compression chamber than the lubricant labyrinth seal;
• and
• the compressor/expander combined machine further includes
• a first inlet that is provided in the first casing and introduces compressed air into the lubricant labyrinth seal, and
• a first air source that is fluidly connected to the first inlet and supplies compressed air to the lubricant labyrinth seal from the compression chamber side via the first inlet.