Window Fan Wall

Our second-floor condo is a corner unit, which means that we have windows on two sides instead of the usual one. The two outer walls are east and north-facing, with large trees lining the North side and the parking lot along the East side. Even in >30°C temperatures the treed area along the North side remains nice and cool, however the challenge is getting that cool air into the house.

The solution that I came up with is nothing special, but I was blown away (pun intended) at just how well it worked, lowering the temperature in the house by upwards of 10°C or more.

Not only is the "Fan Wall" is extremely simple in it's construction, but it is also modular - fans can be added or removed to fit whatever size window you have. In this case, nine Delta Electronics AFC1212DE 120mm fans were joined together to fit the 1150mm-tall window.

The photo above was taken of the original "proof of concept" in which the fans were held together using zip-ties (high tech). I've since added the joiner blocks below and finger guards.

On the left side a 3D-printed joiner block is used for mechanical support:

The fans are all connected in parallel with the wires tucked into the side of each fan.

Each fan is rated to pull a maximum of 1.6A for a total of 14.4A, which is just below the 15A rating of the RioRand 15A speed controller that I had left over from another project. The controller is mounted in an aluminum case which is then stuck to the top of a Dell PC power supply that was rescued from the junk bin (which is also where all the fans came from). The potentiometer that controls the speed is mounted on the side of the case - not fancy but it works.

With the fans running flat out the airflow is quite substantial. The door to my office opens inward, and to close it when the fans are running requires a considerable amount of force.

The next step will be properly integrating it into the automation system to adjust the speed based on temperature, but for now only the on/off is controlled via a relay.