Hi! I am sorry if I am misusing this forum - please feel free to delete my post and I will be on my merry way.

I would like to build up a box trailer to be a walk in fridge of sorts, to keep the contents at around 55 degrees (climate controlled storage). The walls of the trailer will be r40, the ceiling will be r60, and will have a fake roof over it with a 12" space between. To top it all off (pun intended) I want the trailer to be self contained, powered by solar panels on the top.

I am looking for equations that will tell me how much cooling I will need to keep the inside 55 degrees year round. Summer has 20 days of 100 degrees or so. About 1/3 of the days of the year, the high will be 55 or lower. I am hoping to use a window a/c to do the cooling. I have seen ads for thermostats for window a/c's that will let them function as a fridge.

So...I need to find some way to calculate my cooling needs, and then electricity needs to see if the size of the trailer can hold enough solar panels to do the job.

tia