Can home type appliances run on solar?

[cheapliving]

My home frig/freezer went out and I'm having to buy a new one. When reading reviews on a 10.7 cubic ft 110V model available at places like Lowes, reviewers often start out by saying "We bought this frig for....(our daughters dorm room, or tiny apt, or small space in our home, or even an RV). Is it safe to say that if they bought one for an RV, these are folks who don't even need solar and only stay where there are elec hookups? i.e. Either they're snowbirds who stay at the same RV park all winter, or if they travel around like in the summer, leaving one park and getting to the next one before their batteries drain and their ice melts?   

I glanced through the article on electrical which discusses deep cycle batteries and solar, showing calculations of watts, amps, hours, etc. and since I haven't begun my solar van/RV education yet and it's all Greek to me, I really don't have time to figure all that out right how. I'm in my bricks and sticks home trying to decide if I should get a smaller unit, with the idea that one day I could move a smaller 'dorm frig' (that's what I call the smaller ones) which are meant to be plugged in to standard 110V outlets, into a vehicle whose primary source of power will be solar since I can't afford RV parks all the time. The same could be asked with regards to microwaves. I would be eating frozen meals from the frozen food section of the grocery store, stocking up enough to last a week, eating 2-3 of them per day. This may be a pipe dream for all I know if each one drains the batteries for 5 minutes and no solar/battery/converter setup is going to run a microwave for 15 minutes a day, nor a smaller home/dorm frig or freezer 24/7. This is really all I'm asking....either 'yes you can do it' or 'it can't be done.'

I've seen a few videos on those little portable size frig units the size of ice chests that run on solar or propane or whatever, and if that's really my only alternative, please say so, and I will go ahead and buy the 18 cu ft unit that I know will never be used outside the home.
Seeing the size of them, I would need one of those just for frozen things, and have to have a second one for anything refrigerated like milk, lunch meat, etc. Unfortunately, when I see people talking about them, they never discuss or show the connection behind it, connected to whatever power source keeps them running. They are rig tour videos and they just say, "I have a such and such model chest frig (or freezer) and they raise the lid or open the door to show their food inside, then move on with the tour. I have no idea what it's running on, or if they say so, they don't show you the actual connection or power supply source. 

About all I know is that solar charges the batteries, and there's a converter needed that things presumably plug into. I have no idea where the plugs are placed or what the outlets look like that things plug into.

I've been without a frig/freezer in my home for a month and I have to get one NOW. That's right, I've lived with bags of ice in an ice chest for a month.

 

[tx2sturgis]

Yes it is possible, it's done all the time. I myself powered a small dorm fridge with 200 watts of solar, 110ah of AGM batteries, and a 700 watt inverter. 

Is it 'practical'...well that depends on your budget, your vehicle, and the room you have for solar panels and batteries.

If you really need to buy a household fridge now, that might be installed in a vehicle later on, buy the smallest fridge you can get by with, between about 3 and 10 cu ft. The smaller the better, as long as it suits your needs. 

If you have to pay a few more bucks for the 'energy star' rated model, do that. It won't be noticeable on grid power, but it can make a difference on solar power later on. Also, avoid any unit that uses electronic temperature controls, a simple mechanical dial is the best option. A reversable door hinge is a nice thing to have. Often, the single door units have a chiller compartment (freezer) which is not very big. You probably want a 2 door model, with a decent sized freezer, for your frozen dinners. 

Residential fridges are not optimized for vehicle use, but can be adapted, as long as you know what needs to be done, and are willing to make those adjustments.

Also you will need a substantial battery bank and a large capacity inverter to power almost any normal microwave oven, but again, with some space for solar, and batteries, and an inverter (in other words money spent) it can be done on solar. 

(no electronics formulas were harmed in the making of this post!)

 

[cheapliving]

Residential frig has to be adapted in what ways? About how big of a van or RV would you need to hold all the batteries and large capacity inverter for a microwave? (I said converter when I think the proper term was inverter.)

 

[tx2sturgis]

Typically you need a way to secure the door (or doors) when traveling. And if it has glass shelves inside, those can break if something heavy shifts around or falls during transit, which can make a mess.

You also need to consider the condenser, is it a skin condenser? Or a coil condenser on the back or underneath? Some units will have a sticker that says: Freestanding Installation Only.

What that means is you can't build it into a cabinet with no air circulation over the condenser.

And, most of these cannot be drilled into, so you have to fabricate some kind of bracket or trim piece or straps, something to hold it in place on those bumpy roads...you don't want to be driving along and hear that thing fall over inside your rig!

 

[tx2sturgis]

Microwave ovens require a lot of power. You can spend $50 on a cheap one, but you might spend $500-$1500 on a solar/battery/inverter system that can run it for 15 minutes a day. Plus that system will be heavy!

That's why I just size my solar capacity for what I usually run, and then the occasional large loads like a microwave or toaster oven are powered with a generator.

It CAN be done with all solar, but the costs are high.

 

[Trebor English]

A 12 volt DC fridge is more efficient than a 120 AC volt fridge.  

Thermal efficiency involves more insulation.  Residential fridges have thin insulation because people want large interior volume with a small exterior dimensions.  Buyers of 12 volt DC fridges want more insulation to save electricity.

A 12 volt fridge has a 3 phase induction motor where a residential unit is single phase.  That makes the motor more efficient at converting watts to shaft turning power.  

A 12 volt fridge has an inverter that makes the frequency needed for an efficient compressor operation.  A 60 Hz alternating current induction motor rotates at 3600 RPM.  A 12 volt fridge compressor will typically run at 2000 RPM or less.  Gasses compressing, pistons pistoning, and rods rodding don't work as well at all speeds.  A cheap noisy contractor style generator has the engine and generator running at 3600 RPM.  A quiet fuel efficient inverter generator usually has the engine running at 2000 RPM for max power, lower for lower power, and the 60 Hz frequency is produced by the inverter.  A small gasoline engine is quite similar to a fridge compressor with gasses, pistons, etc.  

Yes, you can run a small 120 volt 60 Hz fridge powered by solar, 12 volts DC, and an inverter.  It will need a larger solar array and a larger battery.  Roughly, 2x to 4x what an efficient fridge needs.  If you want a microwave too you are definitely looking at a larger electrical system.

 

[Seminole Wind]

it is not fair, nor is it accurate to make a blanket statement that a 12v dc fridge is more efficient than a 120v ac fridge. yes, there will always be the conversion loss and inverter over head to make up for. but even when comparing same size( both physical dimensions and BTU capacity) you will find that you can come out ahead at times by buying an energy star compliant ac fridge (at a discount) rather than a pricey 12 dc fridge. in the 3 cubic foot range this is easy to do, unless you buy the best of the best in 12 volt fridges. in the smaller sizes like the 15 liter (approx 1/2 cubic foot) you would be hard pressed to find an AC powered fridge and even the 1 cubic foot models use almost as much as a 3 cubic foot model in the ac fridges. but when you go up in size, like to the 8 cubic foot and larger the home/kitchen sized models that are energy star compliant can be extremely efficient.

i personally have both a 2.5cuft 12v dc fridge, the best avaiable by national luna and i have a 3 cuft dorm fridge off amazon. they bot use almost the same amount of energy based on amp hours drawn from my battery bank. then interestingly enoigh i have a buddy that live in an off grid cabin. his big 12+cuft fridge only uses about 10% more power than my little fridges. when you add in the ease of accessing the food in the regular fridge compared to the chest fridge and the fact that a similar size chest fridge takes up about 2 times as much floor space and you cant put anything ontop of it, and the fact that you can buy 2 or 3 regular fridges for the price of a similar sized dc fridge it makes them much closer to equal and certainly worth considering.

as a disclaimer. i started out by saving up and buyinmg the best damn 12v dc fridge available. then 2 years later i had enough solar and wanted more storage and easier access so i bought a dorm fridge and have been running them side by side almost a year. i am very happy with the dorm fridge running on 120v AC, the convenience of getting in and out of it, the readily available replacements in most towns and the energy used has been well worth it

 

[tx2sturgis]

A 12 volt DC fridge is more efficient than a 120 AC volt fridge. 

Thermal efficiency involves more insulation.  Residential fridges have thin insulation because people want large interior volume with a small exterior dimensions.  Buyers of 12 volt DC fridges want more insulation to save electricity.

And the water gets muddy.

While all of that is most likely true, the OP implied that they want a freezer, BUT, a 12v fridge WITH a separate freezer section can get expensive, and I'm not sure they actually save energy compared with an energy star (more insulation) refrigerator/freezer and an efficient inverter with power saving mode. Even operated in freezer mode only, a 12v fridge/freezer is still gulping a lot of energy. 

In other words, comparing a (single section) 12v fridge/freezer in fridge mode, to a 120v refrigerator/freezer with 2 sections, one for freezing and one for the fridge, is not a fair comparison. 

All of the specs I have seen for a 12v fridge/freezer operating in FREEZER mode gulp energy at twice the rate of the same unit in fridge only mode. 
Simply put, keeping frozen food, frozen, takes a lot of compressor run time.

Given the OP's stated need for a residential fridge NOW....I was answering the questions as posted.

 

[jimindenver]

I have a very pricy Engel 40 qt fridge/freezer that is rated to use less power than a A/C freezer. The thing is it has such weak insulation that the thing rarely shuts down when it is hot out. I really believe that a energy star 3 ft freezer with heavier insulation would use less power in the long run.