Just a couple more questions: 1. How tightly do you need to control the reactor temperature? 2. Is there a minimum reactor temperature that you do not wish to go below? 3. Can the reaction run away and become dangerous?
A conventional cooling tower is controlled by a VFD
on the fan(s) as the tower discharge temperature goes up and down. Another consideration for this temperature is the area (climate) in which it is installed. If the area is too hot or humid you may not be able to achieve the tower temperatures you wish.
Also, as Rongai indicates, it may be better to control the reactor temperature with a separate tempered water loop. This will most likely give you tighter temperature control and allow better compensation for reaction rate changes.