12V fridge/cooler Question

[Spaceman Spiff]

i have an piggy-back question: since hot air rises, would it make sense to add insulation on the bottom of the fridge more so than the top?  i have added insulation all around, but mostly on top of mine, but have recently considered that it might be more effective to focus on the bottom... dunno.

You will want to put insulation in relation to where the heat is coming from.  Generally for a refrigerator, equal insulation all around is the best since the air/cabinetry around it is pretty stable.  Now if the bottom gets hot from parking over hot pavement, add more there.  If the top or sides gets hot (from sun or next to a heat source) add insulation there.

the feasibility of using a freezer to keep frozen foods and to make jusgs of ice to use in a cooler to hold fridge stuff. I know most of these 12v freezers are not dual zone and will only do one or the other. Kind of curious about energy use.

it's totally do-able, i did.  i got an 18 quart (small) dometic and made it my freezer, along with a 5 day cooler.  a HUGE step up from soggy butter floating in cold water, but it was a bit of a hassle constantly monitoring the cooler and swapping frozen jugs (i used freeze packs), especially when the weather is warmer.  and the freezer was on a LOT, working it's little butt off to get those ice packs frozen and keep them that way, and i'm starting to think a bigger unit at 40 degrees will use the same (less?) energy as the small one at 10 degrees.  so myself, i just bit the bullet and ordered a 40 quart fridge, and will use it as a fridge, and use the small dometic as a freezer only intermittently, as needed for essentials like occasional ice cream and cubes for drinks.  verdict not in on this plan though...  anyone?

Keep in mind that anytime you convert one energy source to another you loose some.  So converting electrical energy to mechanical (compressor), mechanical (compressed refrigerant) to absorb heat energy from water (to freeze), to water (ice) absorbing heat energy from food (in a cooler) you are loosing energy every step of the process.  Add that solar energy feeding batteries is neither cheap or plentiful, it is energy wise to minimize the conversions as much as possible.

As to starting and stoping a freezer, it depends on the frequency.  There is an energy cost in cooling down the freezer.  How often that happens will determine if it is more efficient to shut it off and restart or to leave it running.  As an aside, it is much more efficient to keep a refrigerator/freezer full of stuff; air has a very low heat capacity (meaning it doesn't hold the cold well).

 -- Spiff

 

[jimindenver]

Beth

I just picked up my Engel MT-45 in Cottonwood. I had picked up as much meat as I could fit in the spare space of my trailers fridge in anticipation but when I put it in the Engel it looked like there was little there. I went back to Frys a day later and picked up $150 (-$46 in discounts) of groceries almost all in meat. That finished filling up the 43 quarts of space and I have meat for a month or more.

I almost bought the Whytner dual zone 63 quart because I was worried the 43 quart was going to be small. I am glad the Engels went on sale because there is no way I needed that much space while having the trailers fridge too. Maybe if it were my only unit it would be nice to have the dual zone but it is considerably larger.