Sunfrost Refridgerator anyone?

[grantgoold]

Anyone using a standard full size Sunfrost refer (highly energy efficient for off the grid living)?

They sure like they might work in a bus conversion without propane.

Thoughts?

Grant

[TomC]

$$$$$

[boogiethecat]

Not using a Sunfrost but I am using a Summit.  But this post is to reiterate what I ended up with after a long saga of messing around with Fridges... my end solution would work really well with a sunfrost...

I started with a propane fridge and like everyone else hated the need to level the bus every time I stopped somewhere, and it wouldn't cool enough in 120 degree desert heat.  I fought it for 5 years.
Then I thought about the idea to go to a fridge with a DC compressor.  Limited choices, expensive, and expensive to repair if the compressor goes out...
So I considered a 120 volt fridge and inverter, and that's what I ended up with... "my way" though...

I got the summit fridge which is very efficient.   Made sure it was NOT an electronically controlled model, ie it has a mechanical contact style thermostat.  I  disconnected the thermostat from the compressor (so much for warranty and UL listings!) and instead connected it to a cheap ($250) ebay 1kw pure sine inverter's on/off switch, and then dedicated the inverter output to the compressor, so when the thermostat demands cooling, the inverter comes on and away it goes.  This arrangement conserves energy by not having the inverter on all the time. 
 Hooked to the 12 volt house system, now I had a fridge that worked regardless where or what I was doing!   If on the road, the alternator powers it... if plugged into shore the 12 volt house converter powers it, and if in the boonies or at night the batteries power it.  Seamless, no switching anything, almost perfect.
Last I added 600 watts worth of solar panels up on the roof and a bunch of AGM batteries from ebay.  Now i can go anywhere and NEVER worry about the fridge- The solar and batteries will carry it for 3-4 days for every 1 day of good sun, and since I finished the project I've not had the slightest problem or worry about the system, it's perfect!!

[Bill B /bus]

Newer refrigerators are more efficient than models of several years ago. You can figure on an electrical usage of about a 1KW/day or less. That's with an ice maker!
1 KW/day at 12V is less than 80 AH/day. Figure on an average of 200 AH/day for normal usage: radio,lights, fan, water pump, TV etc. A battery bank of 6-800 AH's will last 2-3 days without recharging.
Household refrigerators cost  $700-1000 for 18-21 ft3 size. RV unit start at $1200 for the 8ft3 and $2800 for the 12 ft3.
Expected lifetime of an RV unit 7-10 years per industry data.

Those are some of the facts. Your decision.

My $0.02. RV units in all until the coach. Don't worry about level. No boards going bad. If it brweaks there is always a big box store around.

Bill

[Sean]

Anyone using a standard full size Sunfrost refer (highly energy efficient for off the grid living)?

Grant, we use a NovaKool, which uses the 12/24-volt Danfoss compressor.  About the same money as a Sunfrost, and just a little less insulation.  The real difference for us was that the NovaKool is made for Marine/RV use, and so it has mounting flanges and door latches, whereas the Sunfrost is made for stationary use and would have to be modified for use in a bus.  We dealt with the insulation difference by adding some styrofoam between the fridge and the cabinetry.  Just remember to leave plenty of ventilation for the coils.

... You can figure on an electrical usage of about a 1KW/day or less. That's with an ice maker!

I think you meant to write kWh, not kW.

Bill, I think that's very optimistic.  While the "yellow sticker" number might reflect this, even the industry agrees those numbers are only for model-to-model comparative purposes and don't reflect reality.  Frost-free units, even without icemakers, will generally use more than this.  If you do go with a household unit, I strongly recommend buying a manual defrost model, or adding a relay to disable the defrost cycle and the door heaters (if any) while on battery power.

On top of the published numbers being optimistic to begin with, they all start with an assumption of an ambient temperature of 70 degrees.  Not a bad assumption for a house with climate control, however in an RV of any stripe this is likely to be wildly optimistic.  For starters, few of us cool the entire inside of the coach to that temperature while underway, and it is not uncommon for us to see temperatures in the high 80s in the kitchen when we are driving.  For another, when living away from the power pole, we'll try to hold off running the air conditioners as much as possible (and if you have the power for air conditioners, this discussion is mostly academic), and we can be comfortable in temperatures into the mid-80s with just the fans running, so long as the humidity stays in check.  Lastly, it is almost guaranteed that air flow and "breathing room" around condenser coils in a rig is not what it will be in a house.  Bottom line, I would figure an ambient temperature closer to 80 than to the design temperature of 70, which renders the yellow-sticker number woefully inadequate.

1 KW/day at 12V is less than 80 AH/day. Figure on an average of 200 AH/day for normal usage: radio,lights, fan, water pump, TV etc. A battery bank of 6-800 AH's will last 2-3 days without recharging.

Here again, I think you're being optimistic.  We have an incredibly efficient coach, designed for 100% boondocking.  When no air conditioning or heating is needed, we use an average of 175 amp-hours per day.  That's at 24 volts; a 12-volt system would use 350 aH/day.  Now, admittedly, we are full-time and so have all the comforts of home.  That number includes making a pot of coffee every day in an electric coffee maker (no hot plate), microwaving an egg every morning, running the Internet modem and a pair of laptop computers all day long, and running an electric air compressor for about 45-60 seconds every hour.  Still, I would guess that 95% of the rigs out there will use more than we do every day.

Our fridge doesn't even count in that number, because the usage of the fridge is 100% offset by our solar panels.  The 7.5 cubic foot NovaKool uses about 600-800 watt-hours per day, and the solar produces between 1000-1300 watt-hours per day.  On a good day that also offsets most of the air compressor.  On the rare occasion that we lay the bus up for a few weeks (done once in six years, for a 38-day cruise around the horn), we can just walk away and the solar will keep the fridge and compressor running indefinitely.

On top of all the above discussion on efficiency, remember that a household fridge will also require an inverter to run from batteries.  The inverter exacts a roughly 10% energy penalty.  So if your 120-volt fridge uses 1.2 kWh per day, that's not 100 AH at 12 volts, its 110 AH at 12 volts.

Lastly, while a 120-volt household fridge will be far less expensive than a Danfoss-powered DC model, remember that you'll need a true sine wave inverter to run it.  If you're not planning to run any other motor loads, you might otherwise get away with an MSW model for roughly half the price, so this can somewhat offset the price premium of the DC fridges.  Gary's solution to this, BTW, is very elegant, but it does require modification to the fridge that will likely void the warranty.

FWIW.

-Sean
http://OurOdyssey.BlogSpot.com

[TomC]

I too considered a Sun Frost, until seeing both the dimensions (to deep) and the price.  I now have a Norcold 6.3 cu/ft 12dc/120vac compressor marine/RV refrigerator along with a 2.1 cu/ft Norcold chest refrigerator/freezer (either or).  Both have been 100% reliable (mainly because both are R12 freon) since installing in 1994.  But- the capacity is a bit shy.
On my truck conversion, I, like Gary, am going to use a Summit FFBF280W.  It has 13.8cu/ft-over twice what I have now.  It is 75" tall x 27" wide X 24" deep.  Only draw back is the door swing is 51".  Since it has a smallish freezer, I'm probably going to use a Norcold 2.1 chest freezer again.  On our last trip, we used it as a freezer set at 15 degrees (no ice cream) and it cycled just about the same as a refrigerator.
The FFBF280W is rated as a Energy Star, has self defrost (which you could put a switch in), is made in New York, quiet operation.  It uses 440kw of power a year.  So if we take 440,000 watts and divide that by 365 we get 1200 watts per day.  Divide that by 12vdc and you come up with 100amps.  Add in some inefficiencies of the inverter, and it would be safe to say you need around 110 amps per day to run the refrigerator.  Since I'm going to have a 1200 amp/hr deep cycle battery bank, I could run just the refrigerator for about 6 days (try not to run the batteries less then 50% draw down for max battery life).  Works for me.  Good Luck, TomC

[luvrbus]

People I know that have the Sun Frost love it H3 Jim has one in his Prevost he doesn't post here any longer for what ever reason may somebody has a contact for him.
I know several that are building buses that are planning on using a Sun Frost would be my choice of fridges

[rip]

I also have the summit that Tom C is talking about. I put it in last Nov.with our interior remodel and we could not be happier with the frig. We had a propane and that will never happen again.We dry camped for nine weeks this spring and I was very happy with the electric usage.
   Don

[TomC]

Comparison- Summit FFBF280W has 10.5cu/ft refrigerator, 3.95cu/ft freezer, weighs 200lbs, uses 440kw/yr electricity, costs $1,100.00.
Sunfrost RF16 has 10.4cu/ft refrigerator, 4cu/ft freezer, weighs 300lbs, uses 212kw/yr electricity, costs $3,100.00.  Carrying an extra 100lbs, plus the Sunfrost is 34" wide and 27.75" deep, the extra $2,000.00 you'd pay for the Sunfrost can buy close to a year and a half of fuel to run the generator.  Personally-it's just too large for the motorhome.  But-if I had a mountain cabin with limited electricity-I wouldn't second guess buying a Sunfrost.  Good Luck, TomC

[luvrbus]

Tom C you made the point some don't want the hassel of large battery banks, a SW inverter and the generator time do all the cost and the SunFrost will  be about the same in price and I am not a big fan of the Rv propane fridges but the Amish propane fridges like Miller and others work very well we all do it different.

[Chaz]

I've been paying attention to this thread with high hopes that the Summit of which you guys speak would be that answer I have been looking for but, when I went out and checked measurements in my bus, I could only go about 68" tall. Dang. But this has been a very insightful thread! Thanx for all the info!
Chaz

  (wonder if a person could build a fridge with a remote unit and the box would then hold more as per space it took up??     Hey, just thinkin out loud.  )

[folivier]

Not too familiar with these but some boats have ref/freezer units that have a separate compressor.  Might be worth looking at.  You could locate the compressor anywhere.  Don't think it would be cheap though.

[mikelutestanski]

Hello:     My thoughts on norcold 3 way..   The 6 cu foot model (683) we bought has been excellent for our needs . THe six cu ft is great because we have always been able to store what we need.  Now I digress about a bit of required maintenance...
    The first problem I had was last week the propane quit about 4 hours from home. I did not realize it until we got home and later checking I surmised the burner was clogged. THe first clue was the tray under the burner was filled with fine rusty colored particles and junk. 
    So today I read the manual and low and behold the safety maintenance checklist says inspect or clean the burner yearly. Well it has been  some years so I dissasembled the burner and it was clogged.
    A bit later after cleaning and vacuuming and inspecting the burner functioned as advertised.
  SO if you are using the propane system please add a yearly checkup for your propane equipment ; clean and inspect the burner assemblies and flue pipe.  If you are not sure or comfortable with this work see your local gas man or a dealer who has experience with this equipment..   
   FWIW...
     Regards and happy  bussin
                   mike                   

[TomC]

Chaz- Norcold makes a cold plate conversion to make your own refrigerator.

Check out the Summit FF1251W that is 66" high and 11.6 cu/ft (still almost twice my 6.3 cu/ft Norcold).  Good Luck, TomC

[Chaz]

Outstanding Tom!! That one will fit fine!! Price is much nicer too! Does all the Summits have to ability to modify the defrost?

Chaz

Now I just need to sell my 3way Dometic Americana.