Vitrifrigo conundrum

[Lafnbug]

While investigating refrigerator options, I stepped into a pile of analysis paralysis. I am building out a cargo van, which affords me options. Too many. My hubris.

I liked what Sternwake did with his fridge (reefer?), but I yearn to go one better. The C39is has a built in compressor, but the sister C42L has a remote compressor. Besides the slight .1cu/ft of extra space I would gain, it would allow me to move the compressor, and isolate the heat it generates away from the box, albeit with more labor, material, and fabrication. I ain't skeered! The problem is, I don't know how long the lines are that connect the two...

Then, I started considering a lot of the comments here concerning top loaders. This makes sense to me, as they would seem to trap the cold air at the bottom when you open them, thus not having to run as long to reach temperature again. BUT, they don't appear to have a separate freezer space. DAMMIT! I like ice! Otherwise, the C40L is tangible...

Finally, I came to the Front Loader, the C47. I found it intriguing, as it offers a hybrid of sorts. It has a front door, but utilizes a pull out tray for most of the items, plus a top shelf. No discernible freezer. But I like the way it would fit in my floorplan. I think.

All these unit supposedly draw 2.58amps... and I hope to reign this in with a well designed fan/shroud/intake/exhaust system to minimize the thermal loads on my system.

Being that I only have 204w of solar to utilize (battery bank as yet undetermined), I am focusing on pure efficiency of design. I REALLLLY hope to have both refrigeration AND ICE, even if it means small quantites of both. Yes, quality over quantity.

Anyone here have any input on these Italian units?

SternWake, do you produce any quantity of ice with your set-up? It's hard for me to believe that the temperature differential in these tiny fridges will allow two climates. I would be happy with a glassful per day. Do I just have ReeferBrain?

 

[SternWake]

Fraid I don't know much /anything about the units with detached cooling units.

Mine came with a plastic ice tray, and I kept the aluminum one provided with my former Norcold.

Both 'skin off' in about 15 minutes making it safe to drive aggressively afterward. Not sure how long it takes to solidify completely, but Ive made ice, put in a ziplock baggie and filled the freezer compartment with it.

I have removed my freezer door. And have a small fan blowing into the freezer. Which one would think would make freezer less effective. But even the ice tray an inch from the fan is frozen solid. And ice cream sandwiches. The only food ive put in the freezer, are difficult to bite into.

My old Norcold could barely freeze the aluminum ice tray and often id find water leaking from door seal and a nearly empty ice tray. This would happen most everytime I put a warm gallon of juice into it.

the Vf laughs at this load.

my vf starts about 3 amps and tapers down to the 2.3 range by the time it cycles off

 

[Lafnbug]

You have installed a muffin fan in your freezer? I think it's time to stage an intervention....

Is this to circulate colder air toward the bottom area? Do you have problems with floor heat, or are you just experimenting?

 

[Willy]

I have a Waeco CF-50, which has a separate (larger) freezer section. Also have an Engle MR040, which has just the single large compartment. Both are 'chest' style and I've found that it's pretty easy to take advantage of stratification and have most of my stuff frozen solid whilst stuff on the top remains thawed, but still really cold. My Engle is set to abt -2 deg/C. ..Willy.

 

[Spaceman Spiff]

Hoping I'm not hijacking your thread, but here is a thread from RV.net on modifications to a Vitrifrigo frig that is similar to what SternWake did to his. OP talks about using a small fan in the freezer compartment to normalize temperatures in the refrigerator section. He uses interior floor and wall temperatures as his figure of merit. The fan-in-freezer discussion is around the bottom of page 5:
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/26443634/srt/pa/pging/1/page
-- Spiff

 

[SternWake]

You can stage an intervention, but it would take far more for me to give up my muffin fans!! Try and remove them and those people will lose appendages

An internal fan even out internal temps greatly. With my fan unplugged, on a setting of 3.5 of 7 the floor will be 28f, the walls 39f and the back upper part, right under the cooling unit, would be 46f. Measured IR thermometer gun

With the Fan on and a setting of 3.5 of 7, everything will be within 3 degrees of each other and right in the 22 to 25f range.

Generally I keep the fan on 24/7 and the setting of 2.2 of 7 to keep everything 33 to 35f.

The fan does not need to move a lot of air, in fact I researched the lowest amp draw fan I could find, and it moves something like 6CFM and draws 0.03 amps. Since the fan motor also adds a little bit of heat, I figured the lowest amp draw motor would create the least amount of heat for the cooling unit to remove.

Note that the internal fan is not going to make the fridge use considerably less battery power. The overall duty cycle will be nearly exactly the same, despite the difference in thermostat settings. With the fan the temps will be more even, and items placed within will cool down faster. When A solar surplus exists and the fridge turned to a colder setting, the fan will help to remove more heat faster, and then come sundown if the fridge is returned to the normal setting, the duty cycle will be reduced for several hours afterward. This can save some battery power overnight.

I tapped into the internal light 12v for power. I tried a bunch of different locations and orientations and most prefer the freezer door removed, and the fan hanging on a bamboo skewer, right in front of the dial, blowing inward into the freezer at a 45 degree angle. The only time the fan is in the way is when I need to turn the thermostat dial, but it is hardly a big deal. The bamboo skewer just rests in the space above the freezer and body of the fridge. I use some heat shrink tubing to isolate the bamboo from cooling plate and to keep fan from sliding off the skewer. It is easily moveable.

I had a fan in my Norcold too, but had to run the wires through the top of the door seal as there was no 12v source within to tap into. Same results in that fridge, but it made the freezer section much warmer and less effective.

The Fan really allows warm items placed within to cool down much more rapidly. Sometimes when I have a solar surplus, I will crank the fridge up to 4, and then back down at sundown and then the duty cycle is much less for several hours afterward.
Often I forget and wake up to slushy milk in my coffee. I've no real concerns about running low on battery so the cranking up the fridge is more a just because I can, rather than an anal retentive need to use the least amount of battery possible.

I defrosted my fridge on Saturday night and didn't pay close attention to the dial setting when I turned it back on. Last night I woke up at 3 am and when reading, heard the fridge cycle on a bit more than usual. I busted out the IR gun and took a reading on the floor. 21f!. It was set on 3 of 7. Having a big build up of ice on the cooling plate reduces efficiency, and it can build up pretty fast in humid weather. Something to keep in mind.

Sometimes the fan will touch something placed on the upper shelf of the door, and transmit sound to the exterior. I've wrapped the fan with some self fusing tape which is pretty soft, to help reduce this noise, but in general all I have to do is open the door and move the fan or the item on the shelf to make it inaudible again.

While the following is more applicable to larger style fridge freezers used on boats, one can still glean lots of applicable info from it for stand alone fridges.

http://www.kollmann-marine.com/fans.aspx

This guy certainly knows his stuff, but does not seem to be aware of all the high tech muffin fans now available, which can move more air for less current consumed and less noise made.

---

SpacemanSpiff, you've found my other username on Rvnet. I started that thread right after my Norcold failed and I was researching the Vitrifrigo options. I like sternwake better than landyacht though.

BD osbournes tests were done with an empty fridge and show the internal fan increased duty cycle and overall battery consumption by a smidge. He also used a much larger internal fan rated in the mid 20 CFM range which would itself would generate more heat and could explain all the increased electrical consumption.

My tests in use indicate that the fridge uses no more, or an inconsequential amount of electricity more, or perhaps less, in actual use. Having an internal temp range of 3 degrees with the fan is miles better than a 20 degree difference without it.

The internal fan is obviously not a requirement.

I find that thread amusing in the amount of replies that say there is no advantage to doing anything different than how it left the factory and why do some people think they know better than the manufacturer. Perhaps the inept should not attempt to increase efficiency, but these people probably also drive the speed limit in the left lane, and hold up traffic, because they feel that the people in charge know what is best for them and for everybody, as they bleat their way to their destination, irritating everybody who can think for themselves.

In the end, I did not reverse the direction of the fan's flow. I did move the upgraded fan to the other side of the condenser which allows easier cleaning, less noise and better performance than how the fridge left the factory.

 

[highdesertranger]

engel makes a remote system that you supply the box for. so you could use any box. factory or custom box. old rv unit or one you build or an ice chest. go to their web site and take a look. I have never used one, just noticed when I was researching. highdesertranger

 

[akrvbob]

I ave both a Dometic and a Whytner 12 volt compressor fridge and consider the Whytner to be FAR superior, although it is Chinese. Wytner makes a 65 qt fridge freezer model. It's a chest and comes with two doors on top with two seperate compartments each with it's own seperate thermostat. So one can be at zero degrees and the other at 39. I know several people with them and they have been very happy with them, they work.

My Whytner is a 65 qt and it does draw more, 5 amps. But it is so well insulated and has such a great seal around the door, it runs less than any fridge I've ever seen. In every way it is superior to the Dometic, but it is a Chinese compressor. It's only a year old so I can't report on longevity, but I highly recommend it. I wouldn't buy anything else.
Bob

 

[Lafnbug]

Willy, Spaceman Spiff, Highdesertranger, Bob, and Sternwake: Thank you for your replies. I have a feeling that the remote compressor will have little measurable effect, if any, over the self contained versions. But that doesn't mean I won't give it a go =:^)

Stern, basically what you've done is create the refrigerated version of a convection oven. Brilliant! Makes perfect sense, and I've noticed some household refrigerators seem to use this concept as well.

Oh well, back down the rabbit hole for a bit. Willy gave me some food for thought along with all the other units mentioned on this thread. I have my own surfing to do...

I dub this thread "reefer madness"!

---

Hey Bob, I assume this is the one you mean?:

http://www.amazon.com/Whynter-FM-62...=1402970968&sr=1-1&keywords=whynter+dual+zone

That is interesting, thanks for the tip!

 

[Ballenxj]

Hey Bob, I assume this is the one you mean?:

http://www.amazon.com/Whynter-FM-62...=1402970968&sr=1-1&keywords=whynter+dual+zone

That is interesting, thanks for the tip!

That appears to be a nice Fridge/Freezer unit, but the price, OUCH!

 

[Willy]

That Whynter dual zone fridge is one skookum unit! Great price for something of that capacity w. separate compartments. ..Willy.

 

[Lafnbug]

All of these units are extremely expensive, IMHO. I am making a significant sacrifice to enjoy their luxury, so I hope it's worth it! That's why I want to get this right The First Time.

Does anyone have any idea what the lifespan of any of the mentioned units should be? I'm hoping 10 years?

 

[Willy]

I've had my Waeco CF-50 for over a decade, 24/7 solar powered, and only needed to do one repair (controller board burnt out and I replaced it with an electronic thermostat). Have heard of some working for much much longer.

As for the expense, it's more the initial hit that gets ya.. ongoing expense is near nil. Look at those 'extreme' coolers going for over $100: gotta keep supplying them with ice and, adding that cost to the fuel cost (have to go get it), you end up paying the same in, possibly, only a few months. Also, those compressor coolers can SUPPLY ice and can work as a deep freeze.. no spoilage. ..Willy.

 

[SternWake]

My Norcold only made it 5 years. My Vitrifrigo will be 2 in October.

I believe initial quality control at time of manufacture, as well as owner abuse, or non abuse, play just as big a part in longevity.

Locking one up in a 120f vehicle in summer is going to cause the compressor to run near 100% duty cycle and overheat and reduce service life to some degree or another

Blocking the vents, or just allowing too much dust to build upon the condenser, as well as extreme shock/ vibration will all contribute to an early Demise.

My Old Norcold failed, I believe, due to low refrigerant levels. It could not be recharged for less than the price of a new fridge. I think perhaps my rather extensive modifications in a nearly futile attempt to lessen the Noise and vibrations of the Sawafuji compressor contributed to refrigerant loss.

My VF has connections to top off the refrigerant, but I see some of the Dometics and TruckFridges just have pinched tubing where my VF has a refilling port. I've no experience with topping off refrigerant so cannot say whether this is truly the advantage I believe it to be

I took the rather extensive steps with regards to extra insulation and maximum cooling unit airflow I did, not just for maximum efficiency, but also with a mind toward longevity.

And right now, I will consider pulling out a 33 degree beer on a device which uses less than 1/3 the battery power that this laptop uses over the same time frame.

Yesterday, I was looking for the kits where one can add a cooling unit to a Homemade icebox, but the prices I found were significantly more than just buying a self contained unit.

While more insulation can be easily added to a chest style fridge, building a tight fitting cabinet around an extra insulated front loading fridge can make big differences in Duty cycle too. I have 3/4 inches of foamboard insulation added to my fridge itself, 1.5 inches in back, and it slides into a cabinet with 3/4 inches of foamboard insulation with 1/2 inch plywood on one side and 3/4 on the other which also have some insulative value. It has 3/4 inches of foamboard insulation on the bottom and rests on a 1/2 inch plywood shield with a 3/8 thick closed cell mattress pad attached and has the foil faced roof flashing facing the open air passageway below. I also have the same peel and seal type flashing on the plywood sides.

When I do pull the fridge out, the insulation on the inside of the cabinet is about 20 degrees colder than the ambient air, if that gives you an idea how much value the extra insulation adds compared to that just provided with the fridge.

It is the door seals which are the weak link now, but it uses so little electricity as is, that going further in the door seal regard, is not worth the effort to me.

 

[Lafnbug]

20 degrees is a big number. It seems to me that insulation would help with frequency of cycling, thus reducing overall amps used, but I read somewhere your VF is rated at ~2.8amp, but draws closer to 2.5amps? I assume some of that gain is from the lower amp Noctua fan? Does the Noctua replacement fan on your VF run continuous, or is it wired to cycle with the compressor?

I am thinking of going with chest style for efficiency, but would honestly prefer the front door. There just doesn't seem to be a way to add insulation to the front door without it being a kludge. Then again, the drop-in unit just eats up precious counter space. I need to learn to embrace compromise, I suppose...

Sound level, as well, is uber important. Was that one of the reasons you chose the VF? From what I understand they are among the quietest out there. I was hoping the remote compressor versions will allow me to muffle them a bit more as well. Do you think this is worth the effort?

 

[SternWake]

The danfoss secop compressor amp draw begins higher and lowers at the end of the compressor run. The noctua fan draw only 0.07a less than the fan provided.

the danfoss compressor is variable speed. Easily changed with a resistor on t stat circuit. I removed resistor to lower rpm from 2500 to 2000. The higher the rpm, the more amp draw. The faster the initial cool down. And shorter run times. But the slowest compressor speed which still allows sub 50% duty cycle is most efficient. Amp draw at max compressor speed of 3500 is around 6 amps. Any speed between 2000 and 3500 can be chosen with different value resistors.

some chest style fridges vary the speed on their own. I briefly considered adding a potentiometer to vary mine with the turn of a dial, but no need. It performs admirably. at the slowest speed.

The vitrifrigo is much much quieter than my muffled norcold was.

The ultimate difference between a well insulated front loader. And a chest style will not be much, in my opinoon. Convenience and ergonomics win for me.

---

I think the biggest advantage of the remote cooling unit is the extra room in the fridge. Or unless the fridge is going right next to your head when lying in Bed. Mine is about 2,5 feet away but with a narrow clothes closet in between. The norcold drove me nuts. Can barely notice the vf

 

[Lafnbug]

Thanks Stern, I appreciate it. I'm looking forward to a nice 32.1deg beer at the end of this gauntlet! I will keep everyone posted on my toil once I gather pieces and commence. Decisions, decisions... and I still have the rest of the electrical system and floorplan to figure out!

Seems like every time I think I have it figured out, I'm wrong.

 

[SternWake]

Try here for getting the VF you desire. the model you desire might not be listed on this site, but the guy can pretty much acquire any model that VF imports from Italy.

I ordered mine through him and it shipped the next day.

http://www.westyventures.com/parts.html#cart_restore.

Free Fedex shipping too.

Laying out the floor plan can be fun. But visualizing product size without the product is difficult. Cardboard boxes can be your friend in this regard. Cut out and tape together a fake fridge to get an Idea of Size if you are not a CAD master.

And no need to really aim for the smallest fridge available just for saving battery power. I think you'll be happy with the performance for battery consumed, even with a larger model, and you might avoid the curse fest when everything you need to keep cold, does not fit into the ultra mini model.

I wind up buying groceries or beer in amounts I know I can just barely fit, and sometimes I have to open up a six or 12 pack to stuff them inside and get the door closed.

I really hate it when I can only fit a portion of a cold 12 pack inside.

 

[Bdog1]

CAD = Cardboard Aided Design

 

[SternWake]

Good one Bdog1!

Similar to my Muffin fan addiction, I have a hard time seeing nice uncreased cardboard go unused and into the recycle bin.

My Neighbors now ask me If I want their fridge or Flatscreen TV boxes lest they bend and crease it and hear me utter a cry from a distance