I've used plate chillers in the food processing industry for a long time. Big ones, we call them heat exchangers. They can be used for cooking slurry or chilling water.
My concern is the particulate in the wort will tend to clog the channels through the plates. Unless you can filter all the trub and hops from your hot wort, I'd be concerned with clogging and even if that didn't happen, getting the inside clean and free from trub will be difficult.
We have to break the big ones down every couple of months and when we do, they are nasty inside. We are cooking starch slurry to 180 degrees in the first half and cooling to 70 degrees on the second half with a blank plate in between.