Do electric fridges need vents to the outside?

[Joe Romas]

Basic refrigeration 101.
They don't make cold, they just move heat
This is a fact and it does not matter what type of refrigeration is used.

I sold my 1999 17' Casita SD but with modifications running on propane in 90 plus heat last season my freezer was in the single digits and refrigerator section was in the 30's. Here's a picture of my remote thermometer.
So don't let anyone tell you they can only reduce the temperature 40f. It's all in how they are installed and vented.

[Civilguy]

You can accomplish most of the gains required in a Casita installation without a fan by providing the baffling that is indicated in the Dometic installation manual to direct the air from the lower vent to move through the absorber and evaporator section, and baffling or adding a chimney to keep the heat from the top of the boiler away from the condenser.

From previous threads I believe that this was a lot of what Joe did to get his refrigerator working so well.

Ya can't tell the players without a scorecard; here's a nice diagram I found on the Fridge Defend site.



After adding just enough heat at the boiler to boil the working fluid, the objective is to get rid of the surplus heat while keeping it away from the rest of the process.

There. Everyone can now quit posting about their lousy refrigerator performance because I have now taken care of it for everyone for all time. You're welcome.

Oops, I forgot all the other stuff about pilot flames and flue cleaning and proper gas pressure. Oh well, tune in next time.

[MelH]

Some very good discussion and knowledge for all of us DIYs -- thank you!. I love the concept of the absorption chiller due to the LP energy (A 20lb LP tank has about 105 times the energy of a 100Ah battery).
However, because DW closely monitors Fridge temps for food safety, we know the fridge part of our 3.0 Domestic fridge/freezer is limited to a 30dF delta temperature from outdoor temps. And yes, we have adjusted the sensor location inside the fridge.
We work around this by:
1. Closely monitoring fridge temps to ensure they're not 40dF or higher.
2. Moving ice packs from freezer (that continues working) to the fridge
3. Avoid opening the fridge
4. Doing most RVing in cooler environments (high altitude or North in summer).

When this Dometic fails, I'll change to a compressor-based 12vdc/120vac fridge like some of my Snoozy friends have to reduce our constant fridge monitoring and compensation. I look forward to this upgrade. Because I already have outside vents, I'll probably vent the waste heat outside if possible.
Note: I, my Snoozy friends (with 12vdc fridges), and others have 125Ah Lithium Power systems that I installed (I'm a P.E.), powered only from 100W solar. I personnaly wouldn't recommend compressor-based fridge without first upgrading to Lithium power and MPPT solar to create, capture, and completely monitor power. Mel (the boondocking power guy)

[CarlD]

MelH, I custom built my trailer from a Lil Hauley shell and installed a 100 Ah LFP battery, and MPPT controller and 200 watts of solar. 100 watts of solar may be OK in the southwest but is totally inadequate where I live. We have trees. If you have big clear skies and long days you can get away with it, but with little margin. I do fine with full sun and can maintain charge when cloudy, but do suffer from charge anxiety quite often. For a warm fuzzy, I carry a 1000 watt inverter I can power from the truck which I can plug the trailer into to recharge the battery. It's not the most efficient method but it is simple and inexpensive.

[MelH]

Originally Posted by CarlD

MelH, I custom built my trailer from a Lil Hauley shell and installed a 100 Ah LFP battery, and MPPT controller and 200 watts of solar. 100 watts of solar may be OK in the southwest but is totally inadequate where I live. We have trees. If you have big clear skies and long days you can get away with it, but with little margin. I do fine with full sun and can maintain charge when cloudy, but do suffer from charge anxiety quite often. For a warm fuzzy, I carry a 1000 watt inverter I can power from the truck which I can plug the trailer into to recharge the battery. It's not the most efficient method but it is simple and inexpensive.

I (and most of my customers):
1. Park in the shade where possible to keep the RV cool
2. Use a suitcase 100W solar with #10 stranded wire extensions to place solar panel in the sun facing the sun. I travel everywhere this way and have had no issues as long as the sun is reasonably out within my wiring limitation.
3. With the wires we attach a steel cable with loops and locks on each end to discourage theft.
4. Fold and put away panel when not in use.

The Renogy 100W folding suitcase panel I use with Victron MPPT solar controller usually provides me with about 550Wh of power daily. Since we currently use only about 230Wh/day, I have plenty of power. All of this is measured and displayed on my phone app with 30 day history. Last year two of us (one with a Snoozy electric fridge) with my system spent 10 weeks to Alaska and back mostly boondocking and NEVER use the generator we had with us -- both genesis are now retired.

I don't like carrying the 28lb solar panel but this weight prevents it from being blown away by high wind. I look forward to a lighter panel I can secure against wind with tent pegs. Mel (the boondocking power guy)

[MelH]

CarlD, I like you pic with all the fish! Because of customer suggestions, I include and put my 'smart' 125Ah LFP battery in a portable trolling motor battery case with accessary outputs so they can:
a. Disconnect (Anderson connectors) and use the battery for trolling motors
b. Also use it to power trade booth power (lights, phones, etc.) or inverter for indoor emergency home fridge power.
c. Read %charge from their phone within 30' of the battery.
FISH ON!

[CarlD]

MelH,

We have different battery loads. My TF130 uses around 30 Ah per day and the 200 watts of Renogy solar panels will recharge the battery in a few hours on an ideal day. If it's cloudy it will still make it. I only deploy one panel on good solar days.

Interestingly we also went to Alaska last year. We were gone for 80 days, had no generator and never plugged in. The truck provides about 9 amps to the trailer and did most of the charging. When we did park for a couple days we deployed the solar panels. When we were camping in the giant redwoods just north of Crescent City, California, there was very little light and the battery got down to 25% after 3 days, but we made it thru OK.

Like you, I also use the battery on my trolling motor when fishing. I like the weight and longevity and charge it with my generator when necessary. I just set the battery on the boat and clip on the trolling motor.

I am planning a solar installation at my camp also which will use 300 watts of solar, MPPT controller, 100 Ah LFP and Unique fridge and LED lighting. I have the parts, BUT, can't do anything with them because our camp is in Canada

[MelH]

Thank you for the reminder! When I go to the electric fridge (~30W avg.) I'll add the DC/DC converter to charge from the TowV. Without line losses, it puts out 9A. When 'starved' with line losses (12 or 14 AWG from TowV) it still puts out about 5A without shutting down.
My TowV didn't come with cutoff of 7-way Aux Power when switch off so I'm also adding a cutoff on the TowV.
Again, thanks for the reminder! Mel

[CarlD]

Mel,

My victron puts out about 9 amps with a 10 volt input from the TV. I have a dedicated 12 awg from the DC power distribution at the engine to the trailer plug. I think I have some losses in the trailer connector. Input current to the DC-DC converter is about 14 amps. I purchased some DC relays and connected the coil to the toyota 12 volt switched line and the NO contact to my wire. Make sure to use shrink splices or shrink tubing over your connections.

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[wbullivant]

Originally Posted by sigurd

Hi everybody,

I have an old Electrolux gas/12v/230v fridge that I'm thinking about using only as a 230v fridge.

Since I hate all holes and filled up the old vent holes, since I'm relocating the fridge, I was wondering how important it is to have a vent to the outside if I'm only planning to use it as an electric fridge?

I live in Iceland so if the vent is mainly about getting leading heat to the outside, then that's probably not going to be a problem here since, well, it's cold as hell and I wouldn't mind it heating up the caravan.

Hi Sigurd
I have a self built camper van with a Frigidaire 4.5 CF undercounter fridge. A fridge of this type will cost you less than $200 (mine was $125 scratch & dent). A compressor type fridge like this will use about one tenth the power of your absorption unit and will of course emit far less heat. You will probably get comments to the effect that a household fridge will not hold up in an RV environment, but residential units are often used in large RV's and mine has been in use for five years without a problem. I don't use external venting but I do have a 12v case fan in the back to assure good ventilation. IMHO it would be a more satisfactory solution than trying to make use of your absorption unit and involve minimal investment.