The CDUs are essentially just passive water to water heat exchangers with some fancy electronics attached. You want to run a different chemical mix outside to t

The CDUs are essentially just passive water to water heat exchangers with some fancy electronics attached. You want to run a different chemical mix outside to the chillers as you do on the internal loop, it also helps regulate flow/pressure and leak detection with auto cutoff is all fairly essential. Running direct on facility water would made day to day operations and maintenance a total pain.