I am not sure how big of an area you need to cool. If it's not too large you could use some frozen gallons of water with fans blowing across them. Good insulation would help. Another thing i tried was to place a small indoor greenhouse i had directly over an a/c vent. Use what you have. Some of them might even be able to go in the fridge at night. You would need to have them bagged i would imagine d/t low humidity in there. Maybe even finding a old cheap fridge just for the plants.