Les -- I like your thinking. I'd need mix/blend valves for both flows to the GH, though, as well as a pump continuously moving cooling water, as well as the whole cooling water system. I had thought through that, but simplified down to using air as the cooling medium and fans for pumps. I think your answer is definitely The Right Way, but I suspect it's overkill.
Tabs -- I'm a Schomerite, what can I say.
And please, try not to mention Charbucks and coffee in the same sentence. (shudder)
Neil -- good on ya. Don't do any more research, stop reading this thread immediately, or you might end up like me!