I'm not sure how you plan on making this work, but if you run your TECs at 12V then each TEC will draw ~7A and you'll be able to move a maximum of about 10W at a theoretical 50C delta. Not to mention that any thermal joints you have will lower that number, so at 12V don't expect more than 45C delta. Besides that unless you gut your PSU and wire up some huge wires you aren't going to be able to deal with 210A. I'd suggest starting with a MUCH smaller scale first. Also if your process controller is thermostat based it will probably kill the TECs by low frequency thermal cycling. Again...seriously considering doing small scale first. Doing anything with that kind of power input is going to require serious planning and thought. Also consider any safety implications of having those kinds of currents flowing through wires.