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IC2 · 05-02-2016, 05:15 AM

More of a curiosity question that others may have answered elsewhere

From the middle of May to the middle of August and maybe a couple weeks in October we leave our 5er at a very nice campground as a seasonal. We are generally there 3 or 4 nights a week and will run the reefer (a Norcold 4 door 1200 series) on electric the entire time. That in turn seems to boost the electric bill. It's not a huge dollar charge but of course, those dollars could be spent more wisely, if possible, such as keeping said reefer full of more interesting liquid items. With propane, is it a more efficient 'fuel' for that fridge? Is it less costly to run on propane? Is there a safety factor, being an RV fridge (yep, we are all too well aware of the Norcold and the Dometic RV self immolation situations)

**pasdad1** · 05-02-2016, 05:25 AM

What are you paying for propane? What is the park charging you for electric? A cost analysis can be computed. Certainly electric is more convenient as you don't need to refill the propane tanks.

nothermark · 05-02-2016, 07:46 AM

FWIW As was said, do a cost comparison. I have also heard that they run better on propane than electric.

530ktm · 05-02-2016, 08:06 AM

I can not see that the difference would amount to much and it would take a couple months at least to do a comparison. 1 month on propane then refill then 1 month on electric and see the cost of each but then you would be using gas and electric for other things so this may not be completely accurate. To me it would not be worth the time involved to do this but the results would be interesting.

IC2 · 05-02-2016, 09:24 AM

I would guess that the cost of propane per unit to produce X number of Btu's might be a bit higher then electric which is a moving target as we get charged the CGs higher commercial rate at cost that was anywhere between 22 cents per kwh down as low as 11 cents per kwh. Propane for a 30 pound tank (7 or so gallons) has run as high as $30 and as low as $24 and at the same vendor. Actually, I'm really more interested in efficiency then the cost but for sure didn't emphasize that well enough that when I made the post

Bob86ZZ4 · 05-02-2016, 09:32 AM

Quote:

Originally Posted by IC2

Is there a safety factor, being an RV fridge (yep, we are all too well aware of the Norcold and the Dometic RV self immolation situations)

Is the fridge any safer on 120 volt than propane? I thought I heard they are just as likely to catch fire when they leak while running on either source?

Bob86ZZ4 · 05-02-2016, 09:39 AM

You might want to consider switching to residential fridge. I suspect an Energy Star rated one might be the most efficient of all. You'll also gain more interior space. Not much chance of causing a fire. Less expensive than when you have to replace the rv fridge. I think they cool down faster so if you're turning it off when gone it'll cool down quicker when you get back.

timetogo · 05-02-2016, 02:48 PM

I'd run it on electric because if the power went out, it would switch over to gas.

mhs4771 · 05-02-2016, 05:27 PM

Even if Propane were the cheaper method, I'd still run on electric because you don't have to pull the electric cord and take it to be refilled.

jimcumminsw · 05-02-2016, 05:30 PM

With my new camper we did not have a choice; the refrigerator is a residential model and runs on electric only. With our other two 5er we had the dual source model refrigerator were they could run on either electric or propane. After having the residential refrigerator, I will never ever go back to a dual source model refrigerator as they are too expensive to purchase and do not keep the food as cold in the hot humid summer days. Another nice feature for the residential is they come with an ice maker and you can have all the ice you need with this feature.

Gary RVRoamer · 05-03-2016, 02:01 PM

It only takes a tiny propane flame to produce the heat needed to drive the absorption process, so that seems very efficient. Whether it is actually cheaper or not depends on what you pay for propane vs what you pay for electricity, and those prices vary greatly by region and maybe by season for LP.

As for "running better", that's a myth. Once the heater produces enough heat to boil the ammonia refrigerant, the cooling process works exactly the same. It has to, cause the physical laws for the ammonia/hydrogen evaporation and condensation process remain exactly the same, regardless of how the heat gets applied.

The Norcold 1200 is a power-hungry beast, though. Whether electric or propane, in warm weather it will be running continuously all day and much of the night as well.

There is no significant safety difference between propane and electric. If the refrigerant escapes through a pin hole or crack in the cooling unit, it either hits something hot enough to ignite or not. An electrically heated boiler is sufficiently hot to do that, so it's not notably safer than the tiny but open gas flame.

I strongly recommend installing an ARP fridge boiler monitor for your safety and convenience. It will shut down the system if it begins to overheat, but (unlike Norcold's own temp monitor) will also re-start it again to keep your food cold. See arprv.com for more info.

IC2 · 05-03-2016, 08:04 PM

Dang, but it ends up costing money every time I ask a question

Somewhere I thought I had read something that the reefer on propane was more efficient then on electric. Yes, I'm aware that heat is ..... heat regardless of where it comes from, but my foggy memory seems to remind me that the flame from that little pilot sized flame is directed better. So with this all said, may try an experiment this summer while tethered down for 2-3 months in the same spot.

The ARP control seems to be a better way to control excessive temps then a fire suppression system though both are probably even better but at present, only one may be in the RV 'budget' after buying a new sofa bed and a full triple MORryde X-Factor kit. As far as a residential fridge - can't justify that until the current big 4 door Norcold goes to the transfer station dumpster

nothermark · 05-04-2016, 05:12 AM

FWIW I think the "running better" issue is BTU's. The electric heater element has fewer BTU's than the flame.

Gary RVRoamer · 05-04-2016, 07:48 AM

Quote:

Somewhere I thought I had read something that the reefer on propane was more efficient then on electric. Yes, I'm aware that heat is ..... heat regardless of where it comes from, but my foggy memory seems to remind me that the flame from that little pilot sized flame is directed better.

The little LP flame is efficient and well-directed, but it doesn't make the fridge any colder than the electric heater. Once the ammonia coolant boils, it makes no difference how it got heated. And if it doesn't boil, the fridge won't cool at all. So it's possible the LP flame is a little more cost-efficient, but it won't make the fridge "work better", i.e. get colder or cool down more quickly.

You may be thinking of water heaters, where the electric heat elements produces less btus than the gas flame and thus takes longer to heat the water. That's a different animal than an absorption fridge cooling unit.