reservoir + radiator

[mikekosk]

hi u just found a cube aquarium (5 gal) in a back alley yesterday. after cleaning it i thought about using as a reservoir. then i got the idea to put some aluminum fins in it, with one end in the water and 1 or 2 inches outside. would that dissipate the heat enough?

 

[GrimReaperGuy]

Depending on how you are going to cool those fins (actively or passively), and how many/how fine fins you are going to put in, and what it is going to cool, I would say maybe.
It comes down to how many fins you are going to put in this thing, where the inlet/outlets are, and what kind of pressure your loop is operating under.
Without knowing more, I would say no. It would make a fun little project, but you should really not be expecting it to contribute to the overall cooling capabilities of your loop.

 

[I]

An aquarium is a rather poor way to cool, because the semi-cubic shape results in a low surface area to volume ratio. Given a large enough volume of water, it'll still work, but it's not very effective given the amount of space it takes up.

Putting heatsink fins half in the water is of very little benefit, the greatest improvement is having the greatest difference in temp between the hot substance and the room air. Therefore, you would do better to just have a traditional radiator (even if no fan on it) before the reservoir, rather than fins in the larger body of water.

 

[joez]

It would do a very very poor job at cooling. I work with aquariums, and the only way they are chilled (with a couple exceptions) is evaporation. There isn't enough water surface area to cool, and glass isn't a good conductor to cool through. If it were a 5 gal capacity radiator, then you'd have something to work with. Otherwise, it'll just heat up to temp and evaporate alot of water. At those temps, you'd prob lose a gallon every other week.