Refrigerators leave me cold…
At this point I still had lots of choices like whether to use an AC, 12V DC, or a propane refrigerator.
My first assumption was that I would be using a conventional propane refrigerator of the sort that is most often used in RV’s. They are, after all, made for just that purpose, and there must be some good reasons why they are so common. My research suggested that they are quite efficient, using between 1.5 and 2 gallons of Propane per week. I am not sure if I trust those figures though, especially when my son is standing in front of the thing with the door open trying to figure out what he wants.
As I studied the literature more deeply I became concerned about their heat carrying capacity. They warned of having to wait a long time for things to get cold, and even suggested waiting until after it was cold to put the food in.
I read the owners and installation manuals and while nothing about it looked terribly difficult, I wasn’t entirely happy with it either. For one thing there is the whole issue of piping propane into the living quarters. Now I will say up front that I fully intend to use a propane range, a propane heater, and possibly even a propane toilet, so having propane for the refrigerator is not much of a stretch. There are, however, some differences. The range would only be used intermittently and when I am there to keep an eye on it. The propane heater might be on a thermostat and might be on intermittently all night long, or possibly even when I am not there, so it is more similar. Regardless, I fully intend to have a smoke alarm, propane gas detector, low oxygen detector, fire extinguisher, and whatever other safety gear I can think of.
Still, I want my refrigerator to be running 24/7, whether I am on the move or not. Some people seem to think that running a propane refrigerator in a moving vehicle is fine, while others think it is shear madness. I tend more towards the fine category, especially since the owners manuals seem to suggest that it is not a problem technically, while simultaneously taking no responsibility whatsoever for the consequences. It seems that bouncing around helps to keep the fluids flowing in the gravity fed system.
There is also the issue of combustion air inlet and exhaust ducting. Obviously it can be done, but I am not thrilled about punching more holes in my floor and roof. I would also have to be very careful about sealing things up around the fridge so combustion gasses didn’t enter the living quarters. I am going to a lot of trouble to seal things up nice and tight for energy efficiency, and there isn’t a huge amount of air in there to begin with. I would probably also want outside access for burner cleaning and maintenance, which means punching a hole in the FRP outer wall and mounting an access door, also entirely possible but not something I am crazy about.
From what I have read at least some models of propane refrigerators will not work well at temperatures above 90 degrees. I imagine all of them become more inefficient at higher temperatures. The back side of the refrigerator would be conceptually on the outside of the living quarters. It needs to draw in outside air for combustion and exhaust hot gasses. That means if it is 105 degrees outside, my refrigerator is trying to dump heat into that already hot outside air. It doesn’t matter that the refrigerator is physically inside the living quarters and mostly surrounded by 70 degree air conditioned air. This also implies that I would need to be very careful about insulating the outside air ducting so it doesn’t dump heat into my air conditioned living space.
To be fair, an electric refrigerator is just a heat pump, taking heat from the inside and dumping it into the room. I have to believe however that burning propane to make cold has to generate more net heat than an efficient electric powered compressor. Then again, if that heat is dumped cleanly overboard then who cares? At least with an electric fridge, it is dumping heat into a 70 degree room, presumably kept that way by the roof top air conditioner, even if it is 105 degrees outside. The refrigerators performance shouldn’t suffer, though the AC unit will have to work a bit harder.
The biggest thing that bothers me though is the requirement that a propane fridge be level. Now I know that some of you will say that having your rig level is a requirement for many reasons, but I don’t see it that way. Sure, level is better, but I want to be able to pull over to the side of the road and hit the sack without making a big production of it. If I am in one place for a while I might use leveling blocks or jacks, or whatever, but I don’t want to have to. Most roads have a crown so normal parking on the side of the road is going to have the rig leaning to the right. I designed my bunks with the head to the left for that very reason. I find that slightly feet down doesn’t bother me.
The manuals seem to suggest that if the fridge isn’t level then the fluids won’t flow correctly. The internal liquids will puddle in the wrong places blocking the flow. To me that implies a burner flaming away, trying to cool the fridge down, meanwhile my food is spoiling, and I am probably sleeping 10 feet away too stupid to recognize what’s going on. I don’t want to be a slave to a temperamental appliance.
To be continued…
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