Suggestion regarding mixing water-tube heat exchangers in existing, functioning equipment --
A good general practice is to do no harm . . . We should try to make things "fail safe" rather than "fail sorry." Meaning that if something goes wrong it should not cause additional, preventable, damage. Putting modifications on equipment using pressurized water systems can cause a lot of damage if their is a leak.
A method to use a water heat exchanger in a "fail safe" way is an idea I have kept around from an old professor who had worked on old Mainframe Computer designs. He said they used water heat exchangers (such as the coil around the compressor above) to cool the internal portions of the Mainframe Computers -- but they used if on a vacuum system. That is -- water was pulled or drawn through the system rather than being pushed, pressurized, and pumped through the system.
This meant that if a leak occurred, it would only draw air into the system, rather than spraying water into the computer -- it would "Fail Safe." I have put that design into place in printing and baking systems that require a cooling section, as well. If you wish to monitor the system, a drop in the vacuum may indicate a leak.