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The major factor affecting the efficiency of the air conditioner is the heat exchanger. A radiator or evaporator coil would be ideal, but cost and availability are a concern. This page details my attempts to improve performance of my homemade air conditioner with minimal cost.

Strips of tinfoil were first used. You can see some of the copper coiled along the front, from an earlier attempt to improve the heat exchanger. This wins in the cost department, but ultimately the choice was made to discontinue the use of foil as it had the annoying habit of coming undone and buzzing like mad during the night.

The decision was made to completely revamp the copper coils, and install the entire length of tubing on the front of the fan. You can see the recoiling in progress, I did a bit neater job this time (but not by much).

Here’s the completed copper coil on the front of the fan. Cold water is fed from the centre to the outside. Again, I’m unclear as to what configuration if any (cold from the inside, cold from the outside) would lead to superior performance.

I decided to use wire to create a mesh on the front of the coils. (18 gauge wire, Radio Shack, ~$5 – I’m up to 30 bucks now!) This would increase surface area, intercoil heat transfer, and turbulence near the coils, hopefully increasing performance.

I first attempted to solder the wire to the tubing, a stupid attempt as the entire system is designed to efficiently transfer away heat. After several minutes of terrible cold joints, another approach was required.

I ended up weaving the wire from the centre to the edges, and back in. Approximately 10-12 passes were used per quarter section of fan.

Here’s a shot of the completed upper left quarter.

Weaving the wire is an unbelievably frustrating experience at times. The copper tubing usually has a slight gap between the white wire mesh on the front of the fan that the wire can pass through, but at other spots the wire will catch and start to unravel. It helps to have the proper tools (needle nose pliers, beer) to stay relatively stress-free. In this shot I’m halfway through weaving the lower right quarter.

Just be patient and you’ll be fine.

Here’s the fan as it stands right now. Saturday went from evening to night, and that means I need to go somewhere with cold pints and hot women. I’ll complete the remaining quarters tomorrow when I have a bit more time and patience.

Preliminary tests are very satisfactory. The cooling rate has increased, and the room will get a bit colder as well. This will help in extremely hot situations, where heat would leak into the room as fast or faster than the system could remove it.