![](/static/253f0d9b/assets/icons/icon-96x96.png)
![](https://lemmy.world/pictrs/image/0943eca5-c4c2-4d65-acc2-7e220598f99e.png)
- Find a pair of vehicle radiators that are as close to a box fan in size as possible.
- Zip tie them to either side of the box fan. As the fan blows: it will draw air in through the “second radiator” and blow it out through the “first radiator”.
- Hook the out of the first radiator to the in of the second using flexible hoses. Cheap garden hoses might even fit.
- Hook other hoses to the in of the first radiator and the out of the second.
- Run water on through the first radiator, out of the second. This makes the most efficient heat transfer possible.