[pantalaimon]

Why do you need batteries? Why do you think the solar panels to run the heat pump require as much space as you save on the radiator?

And GPUs operate just fine at 90°C

[pfdietz]

It's not just space, it's mass. A solar panel can be made very low in mass. The physical limit comes from the absorption of light in a thin layer of semiconductor. For CdTe, this would be about 1 micron. PV in space could be gossamer thin sheets of thin film semiconductors, with tremendous power/mass.