Compact Absorption refrigerators 12V

[jeroen]

Does anyone have any experience with these? Do they work better than the peltier ones? How cold do they get?

https://www.amazon.com/SMETA-Compact...dp/B072HNBNZZ/

https://www.amazon.com/dp/B01KRFS58Q..._t3_B072HNBNZZ

[Terry G]

Absorption sounds a lot like the ammonia cycle refrigerator that is standard in a lot of our trailers, except only using electricity instead of the propane option.

[skyking]

Peltier modules are only around 5% efficient, some as high as 10% and low as 2%. Also they usually only cool about 36 °F below ambient temperature, so don't expect 30deg in the fridge when its 90deg outside.

[The Minimalist]

Originally Posted by Terry G

Absorption sounds a lot like the ammonia cycle refrigerator that is standard in a lot of our trailers, except only using electricity instead of the propane option.

To clarify; absorption refrigeration is the same as what you are calling the ammonia cycle. They may use AC, DC or propane as a heat source and some can use any of the three; only one at a time of course.

As many of us on this forum have discovered, installation with proper ventilation is as important as having a properly functioning unit. The fridge can only remove heat from the box if the condenser coils can dissipate heat to the ambient air. And of course, ambient air temperature has a direct effect on heat dissipation, regardless of proper air flow.

Good luck in the search.

[cmartin748]

It is absorbing heat and moving heat from one place to another.

[Johnny M]

Originally Posted by The Minimalist

To clarify; absorption refrigeration is the same as what you are calling the ammonia cycle. They may use AC, DC or propane as a heat source and some can use any of the three; only one at a time of course.

As many of us on this forum have discovered, installation with proper ventilation is as important as having a properly functioning unit. The fridge can only remove heat from the box if the condenser coils can dissipate heat to the ambient air. And of course, ambient air temperature has a direct effect on heat dissipation, regardless of proper air flow.

Good luck in the search.

If only you could have some kind of absorption unit to pre cool the air to then cool the coils on the fridge...

[The Minimalist]

Originally Posted by Johnny M

If only you could have some kind of absorption unit to pre cool the air to then cool the coils on the fridge...

Yeah, like a chiller on a large commercial AC or refrigeration unit. I guess you could mount some sort of evaporative cooler panel on the lower intake, which might help in dryer climates.

[Johnny M]

Here is a refrigerator from SunFrost that uses only 12 amp hours per day 12vdc at 90 degrees, and only 8 amp hours at 70...They also have one with an ice tray compartment...might be a viable option...

R4 Energy Efficient Refrigerator

[jeroen]

It costs $1,875 and on top of that they charge your a $45 crating fee, for something smaller than a $130 mini fridge at Home Depot.

With solar panels being well under $1/watt I don't think it's worth it at that price.

[k corbin]

The best option for making sure things will stay cold enough to meet food safety standards is to get a unit that is rated for freezing as well as refrigeration above freezing. Do a search on "12 volt fridge freeze".

Yes they cost more but you do need that type if you to have want reliable cold storage temperatures. And you do want to have that

Don't worry about what they call it, just pay attention to the temperature range it is rated for. If it does not cool below the freezing temperatures don't waste your money on it. The ones that don't go below freezing can't be relied upon in hot summer weather to keep your food safe or your drinks refreshingly cold.

[Raz]

Originally Posted by jeroen

Does anyone have any experience with these? Do they work better than the peltier ones? How cold do they get?

https://www.amazon.com/SMETA-Compact...dp/B072HNBNZZ/

https://www.amazon.com/dp/B01KRFS58Q..._t3_B072HNBNZZ

At 65 watts on DC these will use over 5 amps continuous. In one 8 hr night it would drain a group 24 battery to 50%. On AC a dorm fridge would work better at half the cost. Peltier effect is too inefficient to be useful, don't waste your money. Unless you use a generator there are just three off grid options. Ice, propane, or DC compressor like the danfoss. The last one still requires significant recharge capability. Three way fridges show up used on Craigslist from time to time.

[Johnny M]

We recently came back from a trip with a cooler full of ice and had our breakfast sausage, deli ham and some hotdogs on top in a plastic zip lock baggie to keep water out and to keep from contaminating our ice for drinks. I put 10 lbs of ice in it when we left FL and when we got home (6 hours or so later) I used a digital thermometer to check the temperature of the meats and the sausage read 60 degrees sitting on top of the ice with the lid kept closed during the trip except for an occasional drink or ice accessed out of it. There was still ice but more than half had melted. None of it was below 40, we threw it all out...

For that reason I am seriously considering our options for on the road refrigeration, either an inverter for our dorm fridge or another type of DC powered unit...