Might want some phase-change materials to optimize the thermal banking.
That’s easier for a freezer (very salty water bottles) than a fridge (need some carefully produced waxes), but fridge contents should be more tolerant of temperature variability.
Would add that refrigeration is more efficient at night when ambient temperatures are generally cooler and/or heating needs are greater, so the “ultra-chill overnight and daytime backoff” might not increase consumption.
But I wonder if it just circulates more air and the thermostat doesn’t adjust its set points.
Shifting loads for hot water, if you have big enough reservoirs on contrary change MUCH the game, being able to shift some loads automatically, like leaving a dishwasher or a washing machines, a pumped irrigation systems and so on might significantly change the overall bill to makes investments in that sense meaningful.
https://www.harvest-thermal.com/product
A recent podcast turned me onto them. The idea is to heat water to higher temps than normal and use that extra heat as an energy store for use during peak times.
For me I simply run the main heat pump at full power during the day on p.v. reducing the grid absorption for some hours in winter and for sanitary water almost zeroing it since 300l @60-65℃ (140-149℉) suffice for a whole day, at least when I have enough p.v. a day after another.
Honestly I doubt it's possible to store enough heat with current tech to compensate the home heating needs, it's possible for sanitary hot water (except for a swimming pool) but no more. However for mild climate for some months might be enough to significantly reduce the grid absorption. The sole issue here is that heat pumps now, without any specific reasons, have skyrocketed in retail price enough to make them far less convenient than just few years ago... So the economy is still not much.
[1] an image should be sufficient, I do not know their common name in English, sorry https://lacentrale-eco.com/images/blog/fonctionnement-vmc-do...