You got any windows? people use those type of A/C units in the UK as it's not worth installing a permanent unit for the 3 days per year that it's worthwhile. I've seen a cludge on the market that is basically a board that goes over an open window then you shut the window against it so that it seals and stays in place. It has a hole the same diameter as the A/C hose. Perhaps you could make one from Ply+ some pvc pipe and glue? If you have no windows - you could get a big sheet of foam board insulation cut it to door size +hole for A/C. Leave the normal shop door open and push your makeshift one in place? you could even add hinges and have it as a kind of screen door?