400W to 600W is 40% to 60% of that 1kW you mentioned, that is "a long way" as far as I'm concerned. An AC with a COP of 4.5 - a common rating - will be able to

400W to 600W is 40% to 60% of that 1kW you mentioned, that is "a long way" as far as I'm concerned. An AC with a COP of 4.5 - a common rating - will be able to remove 1.8kW to 2.7kW of heating power from the vehicle using just solar power. Put it another way, a 20% efficient PV panel covering most of the vehicle combined with an AC with a COP of 5 should theoretically enable you to negate the total solar irradiance. Since the car is exposed to other heat sources - indirect irradiance, hot roads, hot outside air, warm people inside it - this is not enough to remove all excess heat from the vehicle but it should at least be able to offset direct irradiance.