University of California cooperative Exention has a couple of publications.
One is Forced-Air Unit to Rapidly Cool Small Lots of Packaged Produce, a
one-sheet answer authored by R.A. Parsons and R. F. Kasmire Publication #OSA
272 including plans. This is good for strawberry and tomato growers.
Wouldn't you know I can't put my hands on the other one, a publication with
measured drawings of a farm-scale 8x8 room using, I believe, a swamp cooler.
You might try contacting David Visher at the Small Farm Center on the Davis
campus his e-mail address is firstname.lastname@example.org. He is extremely helpful
to all owners of small farms in our state.