I'm also not sure if heat pump is a solution for multifamily apartments.
no, it doesn't require good isolation. Good isolation is beneficial, like for type of heating.
Radiators don't have an effect on isolation. However, modern radiators usually have a way higher surface area, which allows heating rooms with lower water temperature.
Heat pumps are more efficient if the difference between source and target temperature is closer.
Nuclear heating of such buildings would use heat pumps too.
2. Just electric heating, if electricity is cheap enough. Very simple and cheap.
But yeah, heat pumps make that more efficient. At significant higher investment costs. Gotta do the math of whether it is more efficient overall to invest in an efficient energy producer (nuclear), efficient consumers (heat pumps) or both.
Nuclear district heating would be very difficult to retrofit.
Hmm. "... if electricity is cheap enough."
> Nuclear district heating would be very difficult to retrofit.
Who said anything about retrofitting? Just build district heating nuclear plants.
https://www.linkedin.com/posts/sollid_denmark-to-investigate...
Again, building one nuclear plant is expensive. But building tens or hundreds of thousands of heat pumps is certainly also and likely even more expensive.
They think the horrific inefficiency of fossil fuels in these uses makes progress look slow and futile as it massively inflates the total energy usage.
In reality, once we get the easy bits of renewable electricity done and are at 80% carbon free electricity, these other markets let us avoid the hard part of getting to 100% clean energy but still make rapid progress on decarbonisation.
An EV or heat pump running on mostly clean energy is a 5 or 6x improvement in carbon even before you account for the grid benefits of having such a large amount of battery and heat storage attached to the grid.