If you fancy a bit of an electronics project, how about this...
You have a great cooling source, however, you have to protect against the loop dropping too low, and risking condensation. Let's say for the sake of argument that you're happy to keep it at 15C or so...
Set up a temp monitor of the FLUID in the system, which then feeds into a microcontroller connected to a stepper motor. When the temp goes above 15C, the cover slides open a bit more, if they drop below 15C then the cover closes a bit more. It'd give you all of the benefits with zero drawbacks.
P.S. If any OcUK'er nicks this idea, please post piccies!