Like many in our group I design and build stuff that may or might not be a good idea...
I left jugs of water out in the cold and stuck the ice in the refrigerator and the stuff in the freezer melted (the ice was not colder than the ice cream so there was no point in adding ice there)
This is plan B. ...

Step 1: Tools

These are the tools I thought I would need: a tape measure, straight edge, square, felt marker, long knife or probe, a saw, I used circular saw with an abrasive blade.
I would have used a table saw with a fence or a hot wire cutter.
Other saws are too messy.
even on this scale planning helps

Step 2: As You Can See I Use a Masonry Blade

I scrounged some foam board & cut it to fill the space on a shelf
Thus, I made the area needing cooled smaller.
I was concerned about blocking the thermostat (I don't know where it is). so I left space near the walls
Unless you are going to try the obvious alternative: packing peanuts in a bag (free, quick, easy)
the rest of this insrtuctible is how one guy cuts foam.

Step 3:

I assumed we could get by with 2/3 of my Refrigerator space
I measured from the lip of the shelf to where the glass ended on the chance that air needed to pass behind

the foam I found was 4" thick That meant I would need to cut into it, flip it, and match the cuts.
even though I could fill more space going 4" wide stacking blocks like books , I went 4" high   and stacked 2 high
I I should have used a darker marker
be warned the blade gaurd is spring loaded and will catch and tug the blade enough to screw-up your cuts
it is the heat   from   friction that does the cutting. keep moving

As planned, I cut one side first
then I stuck a knife carefully through the inside corner I set the foam on edge and cut   using the slot I had just cut as a guide

Step 4:

although the knife left a crater I used straight edge and ran a line to the kerf

I decided to limit the blade depth so the blade would not catch on the edge of the previous cut

Step 5:

You can see the blade caught and drifted.

Commentary:
a refrigerator is a watermelon & turkey holder in a world with few watermelons and turkeys.
most of us live with people who use the front of the shelf

Step 6: This Is What Rich Americans Have in Their Refrigerators

There are "rules " to cutting and measuring, and there are "tricks:" Remember where on the tape the line should go, and where on your mark would be the place to cut.
a "V" arrow on the left, center or right is the standard hint mark

if you stop mid- cut, back up a little -- jostle away from the edges before you start again.
I am done.

warning: Try not to drop the knife or the saw on your foot
better yet lock the door and stay inside.
P.S.
I really do want to know if this is good idea, worth doing, etc.