I doubt you could insulate your thermal storage enough to hold energy from summer for winter months, but for using daylight to give you juice at night it would work perfectly. Also allow you to efficiently heat or cool your home without an electric-heat conversion. Just use the steam to run a heat pump directly.
Not sure how big a reservoir of crushed rock you would need or how many fresnel lenses to heat up the rock or exposed surface area you would need to avoid having to heat the rock without electric resistance coils though? I think if you had the crushed rock on a conveyor belt and passed it under a few meters of lenses to heat and then dumped it into an insulated box that could bring it up to 750C/500F in one pass.
Building that whole system DIY at enough scale to both heat/cool a Monolithic Dome or McMansion/Cabin/Tiny Home with good insulation and run all your main appliances and charge a low power EV car/scooter/trike would be a fabulous challenge worthy of the Diner Master of DIY alternative energy systems, Duke of Wood Gas, Baron von Solar, His Royal Highness King of Contractors NF to undertake!
Will he rise to the challenge? 8)
https://www.thecooldown.com/green-tech/crushed-rock-battery-energy-storage-tech/
RE