Power plants may use off-peak power to compress air into a large storage facility (see Problem 7.55). The compressed air is then used as the air supply to a gas-turbine system where it is burned with some fuel, usually natural gas. The system is then used to produce power at peak load times. Investigate such a setup and estimate the power generated with the conditions given in Problem 7.55 and combustion with 200–300% theoretical air and exhaust to the atmosphere.

Data from problem 7.55

An underground salt mine, 100 000 m3 in volume, contains air at 290 K, 100 kPa. The mine is used for energy storage, so the local power plant pumps it up to 2.1 MPa using outside air at 290 K, 100 kPa. Assume the pump is ideal and the process is adiabatic. Find the final mass and temperature of the air and the required pump work.