Question: for a larger system, can a heat pump be used to increase the temperature of the radiator without making the rest of the system hotter? Thus radiating more heat from fewer panels?
>>audunw+(OP)
Your temperature differential is already 300K, so the efficiency needs to be high enough. 50K change is only 18% more cooling, but if COP=5 then it's also putting out 20% more heat...