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Topic: DC Refrigerator (Read 978 times) previous topic - next topic
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Re: DC Refrigerator
Reply #25
Hey, Andy. Are you running a cryogenics lab in that Airstream!!!  :D
jor
09 27' MB
10  Suby Forester

Re: DC Refrigerator
Reply #26
Jane (and Scott) mentioned NovaKool. And they do have a dual compressor model refrigerator that at 6.8 cubic feet total will fit in our coaches.. I  would hope that the two combined, after factoring in run time, would be about the same overall power as a one compressor box.

I would like to know what a dual-compressor long-term power usage is compared to single-compressor models, adjusted for the decrease in interior space compared to an 8 cu/ft model.
Having a second compressor means giving up storage space..... 8 cu/ft vs 6.8 cu/ft.
Originally  I had thought one of the apparent advantages of going electric was the significant increase in refrigerator volume,

Our Dometic propane-powered refrigerator stays at 40 degrees or lower in very hot conditions and the ice cream stays frozen, I think we will stay with the Dometic for the time being. It has added insulation and fans that make a difference in staying cold and reducing propane consumption.
We always have plenty of propane but can't always say the same about sunlight and solar power

Larry


Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze

Re: DC Refrigerator
Reply #27

"Are you running a cryogenics lab in that Airstream!"

The fridge is normally quite stable at 37° F ± 2°, but the freezer temperature fluctuates more than I'd like, and I'm beginning to suspect that my placement of the Inkbird digital thermostat's sensor on the back wall of the fridge section may be less than ideal.  I may try moving it to the freezer's cold plate to see whether that smooths things out. Balancing fridge and freezer temperatures is always a little tricky with a single-compressor fridge.

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Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"

Re: DC Refrigerator
Reply #28
Hi SoCalendos;  A little late here... The Vitrifigo you listed does seem about 3/4 " too wide, but I bet you can make it fit pretty easily. You would only need 3/8" shaved from each side of the mounting area framework. It is very close. My Dometic cutout seems to be exactly 24". I've never had mine out of position, but there should be 13/16" of spare room.  I believe Andy had a Vitrifigo, possibly the exact same one.   RonB 
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB

Re: DC Refrigerator
Reply #29
Appreciate the feedback on the Vitrifrigo.   I'll try see if Andy posted anything about a Vitrifrigo install in LD in the past and possible experience with the unit. 
2021 27MB 
Towing 2021 Ford Escape Hybrid AWD

Re: DC Refrigerator
Reply #30
I installed Vitrifrigo DP150 refrigerators in my 2003 Lazy Daze midbath and in my first (27') Airstream. The DP150 is a single-compressor model with smaller capacity than the DP2600, as I recall. Some minor trimming of woodwork was required, but nothing major.
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"

Re: DC Refrigerator
Reply #31
And another thought on this thread about cooling air from the back.  The 12vdc compressor refrigerators evidently want to vent hot air inside the rig. I prefer to keep that air outside.    
   Sealing would be needed since my water heater exhaust, generator exhaust, space heater exhaust and engine exhaust are all on that side just below the refrigerator.  And the coach door, so sometimes also the barbeque vapors.
   The NovaKool RFU8320 has the compressor at the bottom but compressed (hot) R134A coolant tubing on the entire back side, much like older residential refrigerators.  RFU8320 — Nova Kool Manufacturing ULC  The cutout views at the bottom of the page show this arrangement.
  This would work better for me.
    Some iRV2 comments indicated the need to put more and better venting out the back, including the electric fans I already have.  I would have to put in better fans and a way to only run them when the compressor was running. (maybe a shutoff delay). 
    The Dometic refrigerator includes a drip pan across the back, just under the fins in the refrigerator compartment. Along with a drain line to below the motorhome. Is there such a provision for defrosting the compressor 'fridges?
RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB

Re: DC Refrigerator
Reply #32
Check out Nova Kool Manufacturing ULC
Canadian, part of novacold company.

I wonder if anyone might have tried using the single evaporator plate Nova Kool configuration to augment the freezer cooling ability of the Dometic unit installed by the factory? Like Larry, enjoying many days of refrigerator operation on propane appeals to me. We often have trouble getting the freezer compartment cold enough without overcooling the refrigerator compartment.

2013 27’ Mid-Bath
2005 Honda CR-V

Re: DC Refrigerator
Reply #33
Hi Keith, you can adjust the ratio between refrigerator and freezer by sliding the white thermal sensor attached to the refrigerator fin on the right side. I'm not sure which way to slide it, but I think downward on the fin will make the refrigerator section colder.  RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB

Re: DC Refrigerator
Reply #34
Hi Larry.  Just looking at the NovaKool 9.1 cubic foot model RFU 9000, single compressor, might fit in your 'frig space.  It might fit in my 'TK. Might need to adjust the cabinetry a bit, but it is close.  The 9000  is pretty tight in back, but it's cooling coils are in the bottom; sucks air from the sides and blows out into the room through the grate at bottom.
     Your front lounge furniture on the E450 chassis might fit better.  Mine has about 1" clearance in back. About 3/4" space on each side for airflow to the back, and about 1 1/4" space at the top. Doable if I didn't mind the hot air blowing out of the bottom grille. I would leave the roof vent open, but prevent airflow through the side vent. Maybe an aluminum panel to transfer heat, but not exhaust gasses.   Power consumption is 5.2 amps, but we don't know what duty cycle would be needed.  You would get three more cubic feet of interior space. (standard Dometic is 6 cu/ft)
      It is also available as a two compressor model.  Same size specs, but 12vdc only.  Maybe the adaptor from 110v AC to 12vdc went in the space the second compressor goes.  Which doesn't matter to us. Plugged into shore power (or generator), the converter can  easily handle it.  The two compressor model is rated 4.2 Amps per compressor, but you get two separate thermostats.    With proper additional fans in the back I might be able to run it without warm air going out into the motorhome. Or if I want to assist the space heater I can direct it into the interior.
    a quick edit:  a source   Nova Kool RFU9000 9.1 CU FT DC Only Two Door Refrigerator & Freezer       The profile picture reveals that I wouldn't have to remove the propane line. Just blank it off.
     another edit:  this boat store calls it a RFU 9200 two compressor model.    Nova Kool RFU9200 9.1 Cu Ft. 258 L Refrigerator & Freezer AC/DC Or DC.       Shop around for prices.        RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB

Re: DC Refrigerator
Reply #35
I realize that a residential refrigerator is the least likely option for LD owners, unless they most often connect their coaches to shore power. However, except for the power source, the residential shares pros-and-cons with the 12V compressor-driven units: capacity, venting, individual temp-setting between refrigerator and freezer (may not be so for all designs), etc. So, hopefully my experience applies to those who are considering 12V refrigerators.

I did little boondocking with either the LD or the Class A. I did do a lot of driving. I liked the propane-electric refrigerators in both; silent, proven, economical. An ARP Fridge Defend unit (in the Class A) addressed the concern of cooling unit damage due to off-level operation. It also provided fans to circulate air inside the refrigerator section.

The Norcold 841 (eight cubic-feet) in the Class A started to decline in performance, and I had to decide what would replace it. To shorten the story, I ended up installing a ten cubic-foot Frigidaire residential refrigerator. It had the evaporator coils built into the sidewalls, so clearance between the sidewalls and the cavity was important. I installed the unit with less-than-recommended clearance, and it worked well enough. Venting was entirely to the inside of the coach. This did not seem to overload the single air conditioner, but then again I did not camp for long in temps above 85-90 degrees F. I had to install stops to prevent the doors from opening while underway. On the "oops" list, I discovered I could not remove/replace/move the interior glass shelves after I had installed the unit in its cavity. I got to install it twice!

I liked the extra capacity, more consistent temperature control and lack of concern for off-level operation. If I camped often without 120V I'd prefer a propane-electric unit with the ARP Fridge Defend, though. A 12V unit is an option for those with solar and battery capacity, of which I had neither on my two coaches.

Mark H.
Former owner, 31-foot gas Class A
Former owner, 1997-8 mid-bath

Re: DC Refrigerator
Reply #36
"The 12vdc compressor refrigerators evidently want to vent hot air inside the rig. I prefer to keep that air outside."

I agree that outside venting is preferable. But of the four 12 V/120 V refrigerators I've had experience with, only one vented inside. That was the dorm-sized Dometic fridge in my 13' Trillium trailer. I wasn't crazy about that arrangement, so I added a fan and larger openings to improve ventilation. (Venting outside would have required major surgery, which I didn't want to do.)

My two Vitrifrigo DP150s and my current Vitrifrigo CF130 all vent to the outside, as installed. They could have been installed to vent inside, and in fact I know someone who installed a CF130 with inside venting, but since my rigs already had provision for outside venting, I took advantage of that.
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"

Re: DC Refrigerator
Reply #37
Good chance most electric refrigerators can be modified to vent the exhaust heat to the outside, the needed exterior vents are already there. For those living in a hot climate, the last thing you want to do is add more heat to the interior in the summertime.
A thermostatically controlled fan or two to vent the exhaust heat from the rear of the refrigerator may prove to be helpful, as they are useful with absorption refrigerators.

It's a new world of improvements to explore for those willing to go to the expense and effort of installing an electric refrigerator and the major electrical upgrades needed to power it.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze

 
Re: DC Refrigerator
Reply #38
NovaKool -     At 12. volts the current draw is 4.2A each compressor. I would hope that the two combined, after factoring in run time, would be about the same overall power as a one compressor box.

Ron, I was hoping that also but the answer was nope..
While the 4.2 is a max amps each, and the freezer, once cooled down and not gotten into often should be less, to be much less,  I am planning more like 6 amps total.
Jane
Jane & Scott
Currently have a 1989 TK  LD we did a lot of upgrades on.
Bigfoot 25RQ Twin on order with early summer 2024 ETA

Our smartphone autocorrects into very poor English.
 We disclaim the illusion of ignorance this creates as we have enough ignorance we rightly claim.

Re: DC Refrigerator
Reply #39
Congratulations on your order of a BigFoot. They seem to still be in business, and are highly regarded. I hope you'll stay around our neighborhood.
     When the time comes, and if I go the compressor route, I would probably go the single compressor route. The price for the two compressor model is much higher. About the best way to save energy with the two compressor model would be to run the freezer as an additional refrigerator. You still have some redundancy if one were to fail.
    It would be convenient to have a gas absorption combined with a compressor model.  While moving or parked really off level, or with plenty of solar/battery you could conserve propane. And electric as a back up if you are low on propane or far from refill sites. On especially hot days usually with good solar, if the absorption was struggling possibly run both to keep the 'ice cream' frozen.   RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB

Re: DC Refrigerator
Reply #40
Ron, I was hoping that also but the answer was nope..
While the 4.2 is a max amps each, and the freezer, once cooled down and not gotten into often should be less, to be much less,  I am planning more like 6 amps total.

Freezers need much more cooling per unit of volume due the the 30+ degree lower temperature than the refrigerator.
The greater the temperature difference from ambient, the greater the need for cooling.  A small freezer could use as much power as a larger refrigerator unless additional insulation is added to just the freezer.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze