Chill for weeks? What kind of thermal mass are you thinking of there? A brick wall is on the heavy side and you'd be able to store a whopping 1/8 of a ton of

Chill for weeks? What kind of thermal mass are you thinking of there? A brick wall is on the heavy side and you'd be able to store a whopping 1/8 of a ton of AC in ten feet of brick wall. It'd save about 0.1kWh of AC power use. A whole house will have many lengths of wall but also multiple tons of cooling requirements, so that doesn't help much. And how are you going to distribute those small temperature differences without wasting a ton of power? And that's after you figure out how to trap a temperature difference in your walls for more than a day.