[exch]

As a completely non-technically-inclined person, can someone explain how this is intended to yield electricity as output?

From what little I do understand, the enormous surface area of the crushed gravel acts as a very efficient heat transfer mechanism, so it can cool(or heat) the Argon, depending on which chamber one is looking at.

The pistons are there to cycle the Argon between high and low pressure.. Presumably to keep the gas flow going. But can't this be done with just the pistons and without the pressure gradient? (edit: nvm this part; the heat energy is obviously generated by this pressure gradient).

Then comes the time to get the heat energy out for actual use. The article mentions that the gas flow can be reversed. So presumably the gravel that was previously being cooled, will now be heated. Isn't this just exchanging the heat between the gravel and gas? How does this yield net energy output?

[al_bundling]

Isentropic PHES Technology Explained https://youtube.com/watch?v=sIxt6nMf-IQ

[exch]

Thank you! It seems my confusion arose from assuming this is a power generator, while it is a storage device.