I'm looking into developing a system that supplies wasted heat of the transformer of my aquarium LED light (which is always quite) to the aquarium water in order to save resources. The heat which is currently emitted into the room ought to be transported from the transformer into the aquarium water using heat exchange and the water flow in tubes which are already available because of the filtration setup.
It's gonna be a hobby project, but I was planning to design a 3D printable enclosing for the transformer and the transmission of heat into the circulating water for different sized transformers in order to increase reusability.
I know from PC hardware cooling systems that water cooling is generally more efficient than air stream cooling (the LED transformer for this project works without moving air). However, I'd like to check what to consider during design of the heat transmission in order to ensure that the water cooling always is more efficient than the static air cooling so that I and potential other users don't risk damage on their transformers.
The following details reduce reusability, but I guess it's fine to develop the prototype localized at first: In the hottest summer (Berlin, Germany) the aquarium remains below 23 degree whereas I'd like to have it at 25 constantly. Thus, I assume that the water can always take all the heat of the transformer.