It trades thermal batteries for electrical batteries. Good choice. Bury it in the ground and have a few hundred pounds of pig iron ingots to be the thermal battery, you're gold. I'd even use lead weights, covered with polyethylene sheeting, as the thermal battery, the density is really nice.

Last year I designed a solar powered freezer for use in Zimbabwe that doesn't need any solar panels at all. Completely passive. It's a cousin to the refrigerator design that Einstein came up with.