Fridge w/out solar?

[Trebor English]

IMO better than ziplocs, not expensive

Google "polar tubes", just glue-capped 2" PVC, cut to the right length and filled 85% full with seawater.

Will likely stay cold 6-8 days in a well insulated box, longer in super Yeti style cooler.

Ziplock bags of water conform to the surface of the freezer compartment.  That promotes faster freezing when electricity is available.  The heat transfers by conduction through the bag.  

The 2" PVC tubes need air flow to remove the heat from the content of the tube.  The PVC tubes are much sturdier than ziplock bags but don't have a conforming shape.  The tubes will work better than bags with a 24 hour freezer.  

In a poorly insulated box like a Haier 1.7 cubic foot dorm fridge that is far from a Yeti style cooler more ice is better.  2 inch tubes stacked in a freezer compartment won't hold as much water as bags that conform to the space and don't have gaps between them.