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Comment by mikestew | Hacker News Reader

The practicality is answered by the fact that many/most recreational vehicles you see going down the road will use a refrigerator like this. As for power efficiency, in comparing compressor fridges to absorption, I think a well-design compressor fridge will use less electricity (absorption fridges can use an electric heater, too), but not by a huge margin. But if your efficiency question is about how well it keeps things cool, ours will make ice cubes when it's in the 80s F.

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The last time I researched this, absorption fridges when run on electric resistance heating use on the order of 300% more energy.

But of course in the case of an RV where you are on a car battery but have a large propane tank, they make sense in terms of energy storage.

With the more cost effective Lithium batteries the higher end RV coaches have all eliminated the absorption fridges and gone with compressors and bigger batteries.

But of course in the case of an RV where you are on a car battery

Most RVs have a "house battery" that usually dwarfs a car starting battery, usually multiples. But even then, running a compressor fridge takes more battery than our little RV has room for (including the roof space for solar to refill those batteries). I think that's a lot of the reason you see compressor models primarily on larger/more costly rigs: they've got room for the batteries, and they don't boondock much. Lithiums just save weight and space (more usable electrons in the same size). If you've got a Class A (rock band touring rig), just line that thing with as many lead-acids as you need. Which is what the manufacturers do; I don't know of a single company installing lithium batteries stock.

Are you saying that they run on a propane flame in the RV?

Correct! Any heat source of sufficient temperature will work, but propane is convenient. I recently took a ferry in Idaho; before loading, people in RVs were told to turn off their refrigerator to reduce fire risk. Searching for "absorption refrigerator diagram" (or checking out the wikipedia page) should provide useful information.

Thanks.

Recreational vehicles as in RVs? They don't use compressor fridges? Is it because the Einstein ones are lighter?

Ours was built in 2018, uses an absorption fridge. They're lighter (assuming that you're going to carry propane anyway), and they don't need electricity (though they can run on it). Though you can get compressor models that run on 12VDC, I'm guessing most rigs with compressors don't park far from an outlet. But I'm not the one to ask on that. I do know that when we're running off solar and batteries, it's nice to eliminate one more thing draining the batteries.

Thanks.

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