[ibmkg]

You are not getting noticeable drop in temperature due the fact that the design is not efficient and that could be due to:

a) Vapor not escaping fast enough from the rig
b) Water is not getting hit by air (could be low surface area of water or improper fan configuration)

The idea of exhaust at top does not look good to me. The vapor would condense back before reaching the ‘window’. Condensed water would raise the temperature again (to ambient). You should not only feel air coming out but also if you place say ‘paper’ at the exhaust end, it should get wet due to vapors. [sort of Moisturized]

In a loop, you should expect at least 5C drop. 10 C drop will be acceptable.

By extended I mean so 'tall'. Reduce the height or you will be left with no useful head. [whats the actual length?]