Fridge Upgrade Question

54d1854d18 Solar Expert Posts: 77 ✭✭✭
I am thinking of upgrading my 7 cu.ft. propane fridge to an electric at my remote camp.
I currently run a 5 cu.ft. fridge made out of a freezer without any issues, what I am wondering is
if it is better to go with a D.C. fridge, or an AC fridge, and if AC, should I get an inverter type,
or just a standard fridge?
I am looking for about a 10-11 cu.ft. so that it will fit in the location of the propane fridge.

Thanks...

T

Comments

  • BB.BB. Super Moderators, Administrators Posts: 30,721 admin
    It does depend on how large of solar power system you want at the camp.... A standard refrigerator (cheap) has high starting surge and requires a fairly large off grid power system to supply the starting surge (a 1,200 to 1,500 Watt AC inverter, maybe around 240 to 300 AH @ 24 VDC battery bank minimum). And you can use the "extra power" for other things (AC powered LED lights around the camp, radio/tv/cell phone charging, etc.).

    Or you can buy an expensive 12/24 Volt DC refrigerator, and a 150 AH @ 24 volt (or 300 AH @ 12 volt) battery bank, no AC inverter. No frost free. The DC refrigerators have almost starting surge current.

    There are (in the USA) some Inverter based refrigerators becoming available... But for the most part, these are relatively large and are "nice/fancy" models that are frost free. In other countries, there are smaller/simpler inverter fridges available.

    With the DC refrigerators, there have been issues getting service, if required, and (in decades past), some issues with quality of the units.

    https://www.homedepot.com/s/dc%2520refrigerator?NCNI-5 DC refrigerators at Homedepot 10-13 cuft models and others

    I am not sure I would say a DC unit is that much more energy efficient as they are not using the energy rating system of Energy Star (i.e., a 13 cuft unit is rated at ~600 WH per day or 219 kWH per year vs ~1,000 WH per day or 365 kWH per year) in a hot room, door opening/closing, etc.... The DC fridges are rated 587 Wh/ 24 hrs (set to -11˚C freezer/+4˚C fridge performance in a +25˚C ambient).

    There is the option of using a converted chest freezer as a fridge (change out the thermostat or add a plug in unit that can be set to 32-40F. Chest fridges can get down towards 250 WH per day--But they still have the 600-800 VA starting surge 

    It is the starting surge and running the defrost heater that adds to the higher power (Wattage) needs (something like 500-600 Watts for a defrost heater, and around 600-800 VA for compressor starting surge, the ~20 Watts to run an AC inverter 24 hours per day for AC fridge) all add up. And you still need the larger AC inverter and battery bank to support the surge (and larger solar array).

    If the solar power was just for the refrigerator and random power for a few other things (LED lighting, RV style water pump, cell phone charging) and weekend/summer usage--I probably would still strongly consider the DC fridge.

    If, however, you can/need more power and have the room/sunlight/etc. to run an AC fridge--The AC fridges are also cost effective, and the "extra" 120 VAC power is mighty handy and easy send longer wire runs for remote LED lighting, remote water pump, etc.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mcgivormcgivor Solar Expert Posts: 3,435 ✭✭✭✭✭
    All options have their tradeoffs, propane needs defrosting, chest freezer adaptation is like living out of a backpack, regular refrigerators have higher inrush needing a larger inverter, DC usually are more expensive due to demand. Inverter refrigerators are probably the most versatile however they are not always available in smaller sizes in some locations, the U.S. for example, if in a location where they are available, look for linear compressor types with either R32 or R600 A refrigerant.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • 706jim706jim Solar Expert Posts: 344 ✭✭✭
    As a  40 year propane fridge user I have to comment:
    I would suggest buying a standard 120 volt AC fridge and a suitable solar system to power it. The apartment size fridge (mine is 11.5 cubic foot) is cheap common and could be easily serviced or replaced if need be. In Canada, my Insignia fridge cost $450 whereas a 12/24 volt DC fridge costs $1800 (!) and does not defrost.
    How large of a solar system?
    1000 watts minimum 2000 watts better.
    Inverter size? Get a 1500 watt inverter or maybe up to 2500 watts pure sine or modified sine. The Insignia fridge has run for two years now on my old Trace modified sine inverter telling me that an upgrade to pure sine is not a pressing requirement.
    1500 watts will run one of anything you can plug into a standard duplex outlet. And has a modest "idle" current draw.
    And regardless if the fridge is running or not, you can cut boards with a Skilsaw, brew coffee, run a TV, pump water or whatever. 
    Interestingly, I could have sold my old propane fridge 6 times. There are still people that want them. But about all you can say is that they require no electricity and that they are silent. They are expensive to run and require periodic cleaning and defrosting.

    Island cottage solar system with 2400 watts of panels, 1kw facing southeast 1kw facing southwest 400watt ancient Arco's facing south.Trace DR1524 MSW inverter, Outback Flexmax 80 MPPT charge controller 8 Trojan L16's. Insignia 11.5 cubic foot electric fridge. My 27th year.
  • softdownsoftdown Solar Expert Posts: 3,330 ✭✭✭✭
    mcgivor said:
    All options have their tradeoffs, propane needs defrosting, chest freezer adaptation is like living out of a backpack, regular refrigerators have higher inrush needing a larger inverter, DC usually are more expensive due to demand. Inverter refrigerators are probably the most versatile however they are not always available in smaller sizes in some locations, the U.S. for example, if in a location where they are available, look for linear compressor types with either R32 or R600 A refrigerant.

    That issue with chest freezers is why my dad switched from chest to uprights. There is no simple solution. I don't see how a prepper is ever going to use the food at the bottom on a chest freezer since said prepper seeks a full freezer.

    Then again the whole idea is being prepared for disaster - a lack of food. If that day comes I don't think being 10 years old is going to prevent consumption to stay alive. Freezer burn is easily removed anyway - a minor inconvenience.

    I have a bad habit of eating the food I just bought. Others say that also comes naturally to them.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • 54d1854d18 Solar Expert Posts: 77 ✭✭✭
    I have been leaning towards the 120v fridge, are there any truths to the Inverter model refrigerators being more efficient,
    or generally better?
  • softdownsoftdown Solar Expert Posts: 3,330 ✭✭✭✭
    54d18 said:
    I have been leaning towards the 120v fridge, are there any truths to the Inverter model refrigerators being more efficient,
    or generally better?

    Just bought an inverter fridge by Daewoo several days ago. Deciding how to transport it 220 miles right now - without laying it on its side. Could use box truck or pick up truck or stand it upright on those "cargo shelfs" that fit into trailer hitches and have an ~300 pound rating. With straps to the roof cargo rack. Thinking pick up truck right now.

    This is 18 cubic foot with a 400 kWh annual usage rating. That compares quite favorably to my 2008 Samsung 18 cubic foot with an ~ 565 kWh annual usage rating.

    Seemed to be the best deal ($400) I could find - was available at a Costco Business Center in Denver - not the other Costco's. Amazon needs about $600 for the same fridge. I find it quite interesting that full size fridges suffer comparatively low ratings at Amazon as a rule. Making me wonder about the handling and letting it sit for a day before plugging it in.

    Good products should have a 4.4 star rating, or better, in my experience. Full size fridges almost never seem to enjoy 4 star ratings at Amazon.

    I have no expertise but am inclined to think that inverter refrigerators are better due to being more efficient. But not radically so.

    I seen a huge 28 cu ft  $3300 fridge with a 650 kWh rating - quite good for a fridge of that size. Costco once again. The inverter models do cost more.

    The Daewoo mentioned above is made in Mexico.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • mike95490mike95490 Solar Expert Posts: 8,864 ✭✭✭✭✭
    if you have to lay a fridge down for transport, let it stand normally for 24hrs to let the compressor oil get back into the compressor.
    Then start it up, and let it run for only a minute. and let it stand a couple more hours to let even more oil get back to the compressor. The pressure it builds in that minute, helps force more oil back to where it belongs (in the compressor )
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
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  • softdownsoftdown Solar Expert Posts: 3,330 ✭✭✭✭
    I'm not afraid to lay a fridge down for 15 minutes then let it stand for 24 hours. I will not do it for four hours.

    The unusual amount of problems with Amazon fridge sales indicates that people do not let the fridge stand after all the jostling around. I would bet on that.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • mountainmanmountainman Registered Users Posts: 378 ✭✭
    My 13 year old frigidaire window ac has been on it's back For a year.
    While remodeling my house.
    Put it in the window waited 24 hours. Working great.
    Blue ridge mts. Renogy pwm 4 100 watt and 2 190 evergreen on Epever mppt 30. 4 Gc 208 ah @12 volts 300 watt psw inverter. 2 kw genny. Iota 45.
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