Yeah. the one good use I see is reefer trailers. Since some times they have to sit long times, with still the coolers running to keep the cargo within demanded thermal limits to keep the cold chain uninterrupted.

Most cooling is obviously needed when it is hot… so in summer and thus sung light time. So the panels would probably nicely run the coolers instead of having a fuel burning generator keeping the coolers going.

During winter, when there is no light. Well it’s probably cold enough ambient the reefer isn’t using lot of cooling anyway.