Tiny House Cool Box

A cool box is....well, a box that is cool inside.  Mine is the thing sitting on the back of the tiny house's porch in the pic below (it hasn't been installed yet in the pic):

It is currently installed now. It has a 4" screw cap on the upper east side which is meant to allow cool air to be sucked up by the hot air vent (yes, my shell has to be air tight for this to happen). It also has a below the floor 6" inlet pipe on its lower west side. It's three foot tall and about 2'x2'.

On the day I showed my nephew the temperature differences inside the cool box compared to the inside shell temperatures:

•  92 degrees F in the hottest area (near the ceiling)

• 81 degrees F on the floor 

• 69 degrees F in the cool box

These temperatures were taken around 5:30pm. Yes it's hot and dark inside the shell still...there's no windows yet so I can check the effectiveness of all my thermal devices.

BTW: the shell itself has a temperature lag of 3 degrees F (with the door closed).  When the sun goes down, the temperature inside is three degrees warmer until 9pm.

Experimental Second Function of the Cool Box

This resulted in a failure from my view point. It warmed the cool box inside temperature by three degrees and wasn't effective in cooling the house.

The second function was meant to cool the tiny house with in reason, say 10 to 15 degrees F from outside temperatures (remember there are no windows and no air leaks at the moment).  This meant I would open the 4" top exit to allow cool air to be sucked out when the shell's door was closed due to the hot air exiting the hot air vent near the shell's roof.

Here's what happened:

Shell's Ceiling Temperature

Shell's Floor Temperature

Actual Inside Cool Box Temperature

This is a cooler day than usual this summer as the ceiling isn't 92F or higher (I've seen the ceiling get up to 117F).

 

This is failure because the cool box is now only 5F cooler than the floor of the shell instead of 12F cooler and the cool box is only 8 F cooler than the hottest part of the shell instead of 20F.

 

Therefore the cool box cannot act as a cool box and a room cooler.  Given the inlets and outlets, the second function doesn't really even cool the shell very well either. After seeing the data (and yes, I've collect more than I show here), I believe there should be at least at 16" cool in and a 12" cool out for a room cooler to work in a 10x12x12' shell.