Idea: using building AC air ducts and AC fan coil units as a bus rather than a one way connection to an outdoor airsource heatpump, allowing hot/cold air to be pulled out of too warm/cool rooms to (a nearby heatpump radiator that can then reuse the heat/cold for) other rooms in need of that heat or cold. Using hot/cold buffer tanks simplifies this. Especially in buildings where you have at least one freezer it makes a lot of sense to be able to use the heat from that to heat other rooms.