Refrigerator for off-grid cabin

[Horsefly]

First of all, thanks to everyone for responding to my quest. I really appreciate it.

In email discussions with my partners, I think we have mostly settled - subject to change - on this one:

https://www.homedepot.com/p/Unique-...ecop-Compressor-in-White-UGP-370L-W/306705211

Some suggestions were for something smaller than we have, which wouldn't work. If this one lives up to the spec of 24Ah/day for 24V, it is pretty darn good. We have lots of time to think about this before next summer, but it looks pretty good right now.

 

[12VoltInstalls]

If this one lives up to the spec of 24Ah/day for 24V, i

Anecdotally people like those units a lot.
I don’t think it will disappoint.
(For me I coughed at the $2K price tag)

For the listed specs of 5.2A at 12V that is essentially the same as my 5CF 120V fridge but there would be no inverter losses. If the thing is built as well as the fridge in the 1958? Forester camper I once owned, the cost/year of the purchase price is probably inconsequential. That Forester passed to a new owner in 2017 with the fridge still functioning very well.

 

[mikejoconnor]

I replaced the fridge in my RV with an Everchill 12v fridge that uses R-600 as a refrigerant. The first 24 hours it ran, including initial startup and cooling dow, it used under 500 watts / day. If you look around you can find some great deals on scratch/dent units at RV surplus stores (<$600).

 

[Hedges]

Our off-grid cabin has had solar since 2017.

My partners ... would be loathe to adding more panels. Long story.

Fairly recent. But how many watts/m^2 are the panels?
My old ones from early to mid 2000's are about 120W/m^2 and today you can get 200W/m^2
Replacing same panels with new (second hand) ones might boost output 50%

AC fridge (if you went that route) means inverter on to operate. But a fridge with ice in the top freezer would stay cold overnight. Inverter could be turned off at night.

 

[Horsefly]

Fairly recent. But how many watts/m^2 are the panels?
My old ones from early to mid 2000's are about 120W/m^2 and today you can get 200W/m^2
Replacing same panels with new (second hand) ones might boost output 50%

Nameplate rating at STC is 280W for a 60 cell panel, works out to be 167W/m². At NTC it is only 202W, which works out to be 120W/m², but to be honest at 9,000' elevation we seem to get pretty close to STC much of the day. I'm guessing we should get some more life out of these panels before we switch out. I have seen some 60 cell panels that are getting pretty high in watts, so I should keep an eye on that.

AC fridge (if you went that route) means inverter on to operate. But a fridge with ice in the top freezer would stay cold overnight. Inverter could be turned off at night.

Yeah, I kinda planned on that when we bought the Schneider CSW4024, as you can program it to automatically shutdown between specified hours. I built in 12VDC powered night lights just to accommodate the idea. However, we never have needed to shut down at night. You have a good idea though, so we may institute that.

 

[carolinabigfoot]

Check out the Sun Star model ST-8CF. It's a DC freezer that also can be operated as a fridge. Impressively energy efficient (if the datasheet is right). Top opening cooling appliances are clever. The cold air doesn't flow out when opening the door.

 

[Horsefly]

Check out the Sun Star model ST-8CF. It's a DC freezer that also can be operated as a fridge. Impressively energy efficient (if the datasheet is right). Top opening cooling appliances are clever. The cold air doesn't flow out when opening the door.

That does look like a good one. I agree that top-opening is best for energy efficiency. Unfortunately, we have a cabin with a kitchen configured like a home kitchen: A spot for the fridge standing against the wall, counter depth, and with a cabinet over the top. Also, the crowd has told me if we replace the current 8cf propane model, the new one needs to be bigger. Sigh...

There has been discussion of adding a fridge in the basement for overflow, and maybe this ST-8CF would be perfect for that. I first need to make sure my new LiFePO4 battery has the juice for one new fridge through this next summer.

 

[nogridhome]

Our off-grid cabin has had solar since 2017. Next spring I'm upgrading from 310Ah @ 24V AGM to 230Ah @ 24V LFP. Our original energy budget has proven to be very conservative, as I believe we almost never consume more than about 100Ah. The exception is hunting season, when a crowd of guys who are definitely not conserving energy crowd into the place for 4 days or so, and I don't think any size battery would be big enough for them. Good thing we have a generator.

We've had a propane refrigerator in the cabin since it was built in the 1970's. The current version (probably about 20 years old) has it's door seals failing, and we are getting tired of its inefficiency.

It appears that with the new battery we may be able to transition to an electric fridge. I'd probably prefer a 24VDC model, but if we need to leave the inverter on all the time I would just have to add in the tare losses in the inverter.

I've done some searches here looking for energy efficient refrigerators, but most seem to be in discussions about RVs or boats and so may be smaller or meant to meet requirements I don't have. We are hoping to find something over 10 cu ft (15 cu ft would be ideal), but I don't know exactly where to look. I know inverter refrigerators are much more efficient, but as far as I can tell they are mostly sold in Europe and Asia, but not here in the U.S. for some reason.

Anyone have some recommendations?

I have used this Danby refrigerator for several years. I find it to be extremenly efficient and VERY quite. Screw compressor is the latest greatest refrigeration tech. I liked it so much I went and bought its little cousin - the freezer. (It happened - pics attached)

 

[Horsefly]

I have used this Danby refrigerator for several years. I find it to be extremenly efficient and VERY quite. Screw compressor is the latest greatest refrigeration tech. I liked it so much I went and bought its little cousin - the freezer. (It happened - pics attached)

That fridge does look like a good one, although the Danby site says they don't make it any longer. Sounds like my partners and I have decided we would rather spend the extra money and get one that will run off of 24VDC, for greater efficiency and so that we don't have to keep the inverter going when no one is there.

 

[toomanychoices]

For my off grid life I began with limited panels, so I went with a chest freezer 12cubic foot, and a Johnson controls temp controller, Works fine as a refer. Been running it nonstop for 10 years. Uses about 1/4th-1/3 the power of any fridge on the mass market, and dirt cheap in comparison. The only issue being that the metal interior has rusted. Try to find one with plastic.
I now have plenty of power so I went with a conventional for the new house, but that freezer/refrigerator is still running for nearly nothing.

 

[Horsefly]

For my off grid life I began with limited panels, so I went with a chest freezer 12cubic foot, and a Johnson controls temp controller, Works fine as a refer. Been running it nonstop for 10 years. Uses about 1/4th-1/3 the power of any fridge on the mass market, and dirt cheap in comparison. The only issue being that the metal interior has rusted. Try to find one with plastic.
I now have plenty of power so I went with a conventional for the new house, but that freezer/refrigerator is still running for nearly nothing.

Yeah, if my engineering mind was in charge so I didn't have to keep my siblings and my wife (and daughters) happy, modified chest freezer would be my solution. The physics just makes more sense than an upright where all the cold flows out when you open the door. It still might be an add-on solution for the basement. The problem is that when my father built the cabin 50 years ago, he built a traditional kitchen with wall cabinets, base cabinets, and a hole for the fridge to fit. So a traditional fridge is the only thing that would look right and fit in that spot.

As for rusting on the inside of the freezer.... Do you defrost it periodically? Is this living in a humid environment? My place is in the mountains of Colorado, and it is very dry. I'd not think rusting would be a problem.

Anyway, I do appreciate all the suggestions here. It seems like we have @toomanychoices!

 

[12VoltInstalls]

As for rusting on the inside of the freezer....

Sanding and painting never hurts anything

 

[toomanychoices]

Yes I have sanded, osphoed and epoxied, and it lasted a year before rusting again. I actually think it is because I am running at fridge temps rather than deep freeze as it was designed for. For others information I suggested the plastic interior. It is in a humid environment as it backs up to a 400' greenhouse, even though I am @7150 ft, central NM, darn dry. But for $300 10 years service, frugal power use. not bad.

 

[Eastern Dave]

I upgraded to a Samsung 18 cu ft fridge using a digital inverter compressor($895 cdn at Home Depot). My solar power provision is 3 by 335 watt panels charging 4 Rolls L16hc batteries (around 6 kw-hrs usable storage) hooked to a 1500 watt inverter. Fridge runs full time from April to December, so far no loss of power and every weekend we always have lots of ice. uses about 1 kw-hr per day. Solar production 3 - 5 kw-hrs per day. So have no worries about this use.

 

[TampaSteve]

We have the Isotherm Cruise 219 in my RV. That would be 219 L almost 8 cf. Works super great , Danfoss compressor and uses about 100AH a day, but thats on the road in a hot RV, might be a lot less inside. Unfortunately its made in Italy and they temporarily stopped production although is rumored to start again soon.

Its 12/24V and 120v.

 

[12VoltInstalls]

to a Samsung 18 cu ft fridge using a digital inverter compressor($895 cdn at Home Depot)

Do you have a SKU for that?
I know someone that needs one, and she is not liking most units available.
For myself I’d like to look up the running watts.
I was in the store yesterday (HD) and the 10-14CF models were either free and like 120-140W. I should have bought the ~11CF 60W last year that was $259 but that size range is basically $400 right now

 

[Eastern Dave]

Do you have a SKU for that?
I know someone that needs one, and she is not liking most units available.
For myself I’d like to look up the running watts.
I was in the store yesterday (HD) and the 10-14CF models were either free and like 120-140W. I should have bought the ~11CF 60W last year that was $259 but that size range is basically $400 right now

The model number is RT18M6215SR, Store SKU 1002437215, Store SO SKU 1002433264. This model is shown to come with an automatic ice maker which the one I have does not have. Good luck in finding data on the actual running watts. All I know is that it must be in the 1 kw-hr/day range for my solar system to power it without interruption April to December.

 

[12VoltInstalls]

Good luck in finding data on the actual running watts

I see what you mean

 

[Pappion]

JC Refrigeration has some interesting options.
You can upgrade your RV frig to safe Freon R134A which retains the Propane Gas / AC Electric functions.
Your RV Frig can be converted to a compressor at 120vac, 24vdc, or 12vdc. excerpts:
A. again unlike a residential fridge that draws between 6-8A 960W AC, my unit draws only .8 A 92W which is less then what most inverters draw by themselves
A. on paper the 12V is the most efficient @ 7.5A 90W, but it runs some slower than the 120V,
A in our testing @ 80F the AC compressor will run approx. 56% and the DC approx. 64%, that is not opening and closing the doors.
JC Refrigeration
They also offer factory installation.

 

[sunshine_eggo]

JC Refrigeration has some interesting options.
You can upgrade your RV frig to safe Freon R134A which retains the Propane Gas / AC Electric functions.

Please link to this. I couldn't find it. My understanding is that the compressor cooling unit completely replaces the absorption cooling unit, so you lose the propane/AC option.