Refrigerator Cooling, Propane vs. Electric

[k9dad]

Question about refrigerator cooling during preparation for a trip. Does it cool faster when plugged into electric (in my driveway) or just leaving the propane on and cooling that way?
Thanks for any input.

[JC2]

k9dad wrote:
Question about refrigerator cooling during preparation for a trip. Does it cool faster when plugged into electric (in my driveway) or just leaving the propane on and cooling that way?
Thanks for any input.

The rv fridges that we have used over the years usually took about the same time to cool down to acceptable operating temps whether on ac or lp. The fins inside the fridge started to feel noticeably cool at 8-12 hrs and after 24 +- hrs, the freezer and fridge were at 0/mid 30's respectively.
Last spring(2015), we did replace our Dometic NDR1062 rv fridge with a Haier 10.2 cu ft residential as the cooling reliability became less than acceptable. We had the install checked for correct specs, installed the Amish exterior coils and finally crossed the line when they developed a leak after 18 months.

[dougrainer]

smkettner wrote:
Propane is faster for me. Gets started before I pull out of storage. No need to plug in when packing.

Not faster. MORE convenient. Doug

[time2roll]

Propane is faster for me. Gets started before I pull out of storage. No need to plug in when packing.

[koda55]

We keep a couple of milk gallon bottles in the freezer and when we are ready to cool the fridge we take them out and put them in the fridge freezer. Helps to cool it faster whether on gas or electric.

[prstlk]

If you take a can of hair spray (don't use it myself as I don't have hair and my barber uses a 1 guard to keep me presentable) if you hold the nozzle down the can will become cold. The refrigeration principal uses a compressor to duh compress a a gas (freon). When that compressed gas goes through the system it releases cold air, and carries off warm air to the coils, and then it starts again. The 2 way rv fridge instead of delivering a cold source removes the heat through absorbing the heat and carrying the heat away from the unit (fridge) again through a coil. The rv fridge uses absorption of heat vs. Refrigeration in the conventional sense. If your not confused by now, I am.

[Kayteg1]

mrsportys wrote:
The real question is...do you run propane while your driving ( vs having the generator on) ?

[mrsportys]

The real question is...do you run propane while your driving ( vs having the generator on) ?

[TNGW1500SE]

I would use the electric and make sure RV is level. Freeze all meat at home in house freezer, then transfer to the RV refrigerator even if not putting that meat in the freezer part. It will help the refrigerator get cold as it thaws out in RV. Make sense?

[dougrainer]

prstlk wrote:
What's important to note is these units are not refrigerators in the conventional sense. They don't cool but rather absorb heat. The best thing to remember is what ever you put in the fridge, pre cool it. As you travel introduce warm items gradually. Don't put 2 12 packs in and expect cool in 12 hours.

Pre cool your fridge 2 days before your leaving and gradually add the stuff.
Jmho

ALL refers and Air conditioners operate under the same principle----They remove HEAT from an item and the result is COLD. Doug

PS, what is your idea on how a refer operates?

[prstlk]

What's important to note is these units are not refrigerators in the conventional sense. They don't cool but rather absorb heat. The best thing to remember is what ever you put in the fridge, pre cool it. As you travel introduce warm items gradually. Don't put 2 12 packs in and expect cool in 12 hours.

Pre cool your fridge 2 days before your leaving and gradually add the stuff.
Jmho

[pianotuna]

The duty cycle on an absorption fridge with the door NEVER being opened is 2:3, or 16 hours per day. That was with an ambient temperature of 60 F.

Jim@HiTek wrote:


Two door refer, 1 person usage, 3 amp when calling for cold, 8 hours/day average On time (I avoid hot areas), $0.085/kWh rate. For me, it comes out to around $90 per year.

[Jim]

DrewE wrote:

Jim@HiTek wrote:
If you turn it off whenever you return from a trip, you'll likely get 7 to 10 years of useful life so I always leave mine plugged in and on all the time. The pluses for leaving it plugged in and running continuously (it's ready to go when you are!) far outweigh the minimal power usage. Your batteries are always ready too.

As far as which method cools fastest? Never saw a much of a difference those few times I had to shut it off. But my gut feeling is for my Dometic, gas was faster. Slightly. My Norcold? Seems faster with electric. I'd tend to agree that there's not enough difference to be concerned.

That "minimal power usage" of an RV fridge is somewhere in the rough vicinity of 2000 kWh per year, or perhaps $400 for the year depending on your electric rate. Maybe that's minimal to some people, but it's more than enough for me to shut it off when not in use and start it up (or do without) before taking a trip.

For a quick trip, I usually just toss perishable food into a cooler and dump in the ice from my (house) freezer.

From my calculations for my refer in my RV surviving my lifestyle, it isn't so high.

Two door refer, 1 person usage, 3 amp when calling for cold, 8 hours/day average On time (I avoid hot areas), $0.085/kWh rate. For me, it comes out to around $90 per year.

[Old-Biscuit]

dougrainer wrote:
The BTU output of 120 and LP are almost identical. There are factors that affect how well and fast either source cools better. BUT, BOTH will be equal as long as all operational parameters are to spec.
1. 120 line voltage will affect 120 operation. Anything below 114 volts will not allow best 120 cooling.
2. LP gas pressure and the condition of the burner and burner Chimney will affect best LP cooling. Low(below 11 inches W/C) it will not cool as well. Dirty burner or Chimney will not allow the Heat BTU's to be efficient.
Last, for some reason some think because it is a HOT flame, it MUST cool better. NOT SO. The Flame itself cannot heat the boiler system to operational temps. So, ALL RV refers have a metal spiral baffle in the Chimney just above the flame. THAT spiral baffle causes the LP flame to disperse into a round heat source to heat the Boiler system efficiently. The 120 element is attached to that boiler system and is 6 to 8 inches long and transfers its heat directly to the boiler system. Remove that baffle and the LP would not cool at all. So, BOTH LP and 120 are even in cooling. A reason to run on LP would be if you have verified that the CG or source of 120 is below 114 volts. This may happen in areas where high RV usage and AC running has dropped the line voltage. Doug

Ding, ding, ding..........

[pianotuna]

Having done a "back yard" experiment I can say that my fridge takes about 6 hours of run time until the first cycle when running on 120 volts AC.

I agree with the 2000 KWH per year which is why I unplug when not in use.