Im not suffering as much as you guys with regards heat, but its been pretty warm here in the UK last week.

Right. I got two large van radiators off eBay. I got two Ford Transit ones.
I linked the two together with braded hose and sealed up all the connections using jubilee clips.
On the inside one I covered it with a box and left some round connectors on it, to suit flexible ducting that connects to the miners.

The outside one is mounted with a 230V fan to blow ambient air over it.
I then have a pump that pumps water through a copper tube with small holes, to spray water over the coil in front of the fan.
The discharge turns upwards and makes the water drip back down into a tray to re-pump over the coil.

I filled the radiators with water and used a central heating circulator to pump water between the outside and inside coil.
Gives a massive temp drop with the water spraying over the coil.

When the water heats up, dump it and charge the tank with fresh cold water.
In the UK im getting approx 15 Deg tap water.

Currently working on an Arduino with a temp sensor to monitor the water then dump when it gets warm.
Just a solenoid valve to dump with a simple ball cock to fill with cold water again.

Miners suck air from over the indoor coil which cools the incoming air significantly.
The adiabatic cooling to the outdoor coil really works.

Im hoping to build the thing properly in some stainless steel boxes and install it permanantly over the next few weeks.