Compressor Fridge Upgrade Options

B Eventually · 03-24-2016, 05:43 PM

We’ve just ordered a Trend 23L and we’ll be replacing the stock two-way fridge with a compressor fridge. (Wanted a B, but finally accepted that we needed a C to fit 5 people + 140 lb mastiff mutt.)

Globally, there are several manufacturers of compressor fridges and chests. I know that

Davydd has a Nova Kool
Wincrasher's 59K has a NovaKool as well
Booster has a Isotherm (still having reliability issues?)

Does anyone have a Vitrifrigo?

Engel (known for their chests) has a front loading model available in the US now too.

Are there other options out there? Any favorites?

avanti · 03-24-2016, 05:54 PM

Add me to the "NovaKool" list. It is great.

Frankly, I don't think there are big differences among any of the fridges that use Danfoss compressor. Certainly, I would expect reliability to be similar. Maybe some are better insulated than others--dunno. In any event, adding extra insulation is worthwhile.

booster · 03-24-2016, 06:05 PM

I think a big consideration, other than size and fit in existing opening, is how they vent the cooling. That was the biggest issue with our Isotherm, that is made to take air in the bottom under the door and vent back out into the room above the door. The cooling unit is on the r/h rear of the unit, with a fan blowing toward the inside of the van. Our Roadtrek has outside frig vents, so there we considerable issues with the hot air not going out the upper vent and looping back into the compressor. Once I figured it out, I made an inlet duct out of urethane insulation board, and but a full baffle between the upper and lower vents. It then ran very well. We have had two failures of the Danfoss mechanical thermostat, however.

The units that have the coils on the rear of the frig are much more suited to the external vents than the ones like the Isotherm, which would probably be better if the venting is into the van like on a boat.

I think Vitrifigo vents like an Isotherm. Many of the others vent in the rear.

gregmchugh · 03-24-2016, 06:19 PM

I noticed that the Isotherm refrigerator used on the Earth Cruiser has the Istotherm Smart Energy Control option which is a pretty clever bit of technology. Not sure which models have this option available and the price of the units with this option included...

Indel Webasto:Â*Isotherm Smart Energy Control

B Eventually · 03-24-2016, 06:28 PM

Good to hear you enjoy your Nova Kool Avanti. I remember you mentioning your compressor fridge before too, I just couldn't remember you mentioning the manufacturer.

Booster, thank you for the venting details. We’ll be working with existing outside vents as well. Several of the Nova Kools have coils on the back, so that’s promising. Their cutout dimensions not as much so...

Has anyone swapped a fridge themselves? I imagine sliding a new compressor fridge in would be fairly straight forward, but there would be the existing propane line to deal with.

booster · 03-24-2016, 06:45 PM

We did ours ourselves. The propane lines were behind the frig to the outside of the van, accessible through the lower vent removable panel. The propane continued on to the stove and furnace, and back to the water heater, so I just capped the line to the frig at the cross fitting. The new frig cleared the propane stuff so it all could stay. Roadtrek had water lines to the sink through the opening that I did need to move to the outside direction a bit to clear the frig. Ours is a bit shorter (same CF) so I set it on, and bolted to, aluminum angles bolted to the sidewalls of the cabinet. That left just enough room under the frig, accessible from the outside, to store the van jack and some extra extension cords.

Hein · 03-26-2016, 02:55 PM

We have a Norcold DE-0061 7.1 cubic foot refrigerator freezer with the Danfoss compressor. I reversed the doors and machined the front panels. Photo of the install during the build. It has built in vents but I elevated the unit and added more vents underneath. The cabinet it is mounted in does not go up to the ceiling and has a vent towards the back.

wincrasher · 03-26-2016, 03:09 PM

Here is the list of Nova Kool sizes. I like mine very much. Luckily, my boat came with the exact same model of fridge that I have in my van, so I only have to be familiar with one model.

https://lookaside.fbsbx.com/file/Nov...99AQyTaVh-yFxO

booster · 03-26-2016, 03:28 PM

Quote:

Originally Posted by gregmchugh

I noticed that the Isotherm refrigerator used on the Earth Cruiser has the Istotherm Smart Energy Control option which is a pretty clever bit of technology. Not sure which models have this option available and the price of the units with this option included...

Indel Webasto:Â*Isotherm Smart Energy Control

That system is basically a "cold plate" setup like has been used in boats for a long time, that has been automated. Whenever the unit sees that there is excess power available from the engine alternator, shore, solar, etc (sees charge level voltage), it goes into full speed, continuous cooling to chill a cold plate in the frig. When there is no excess power, it goes back to normal mode, and the large heat sink cold plate keeps the frig cool without the compressor being run, saving battery power.

I don't know if they have changed it, but as of a couple of years ago, they were permanently set at 41*F temperature IIRC, which some felt was a bit too warm.

Yan Seiner put on into his Roadtrek 200 about the same time we did ours. He did have the same venting issues we did, but I haven't really heard much of anything about how much energy he saved with it.

AZ ADVenturist · 03-27-2016, 04:55 PM

Ours is NORCOLD model: DEO788B, 3.1 cu.ft. Incl. Tiny freezer.
We like it because of the compressor & 12v/120 features.
And maintains cold temp pretty well when running.
But- it seems to cycle on & off a Lot. Even at night in cooler temps.
It's gotten so annoying at night that if we have no meat or frozen items,
I turn it off! It does then loose cold by morning. I know that is not the intended use, but suspect it is either not properly vented &/or well enough insulated. I can't remedy either DIY. Or take it to a dealer. I'll take it to an independent shop, if I know what the problem is.
It's a 2013 Chev.R/T 190. We bought used.
Any ideas are appreciated.
Thanks, Ric. in Arizona.

avanti · 03-27-2016, 05:38 PM

If your problem is inadequate venting, it will be fairly obvious--the inside of the cabinetry around the back of the fridge will get pretty warm. Just find access and stick your hand in.

If that is your problem, and your intention is to vent into the inside of the van there is an easy fix: Just cut a round hole somewhere and mount a computer muffin fan as an exhaust from the cabinet. A small fan is very quiet and will make a world of difference. We have such a fan that vents into an adjoining closet. Works perfectly--there is plenty of leakage from the closet. You can also get inexpensive little temperature-sensing boards that will modulate the speed of the fan according to need. They are intended for use in stereo cabinets. Check eBay.

booster · 03-27-2016, 09:47 PM

Short cycling of the frig is usually not a venting/overheating problem, from what I have seen. It would be more likely to be either a bad thermostat or the placement of the probe.

The mechanical thermostats just go on and off based on the temperature of the sensing bulb, which generates pressure in the tube to the control. The pressure works against an overcenter spring in the control to go on and off.

If the sensing bulb is in an area that gets cold too quickly when the compressor runs, it will cycle off too soon, causing continuous short cycles. If the control is getting weak, even the correct temp sensing pressure can cause early activation.

To rule out the ventilation, which probably won't be an issue in a 190, just remove the lower grill and see if it is getting hot at the upper area of the condenser without that heat getting out the top vent.

To check the bulb location, just move it to place further away from the cooling coils in the freezer box.

peteco · 03-28-2016, 07:44 PM

What freezer temps are you guys getting with your compressor fridge? I had seen some people complain about freezer temps only in the 20's. It is best if they are down in single digits, which my 3-way does well. OTOH, my fridge temps are a bit flaky, though a recent fan mod I did has helped a lot.

booster · 03-28-2016, 09:17 PM

Quote:

Originally Posted by peteco

What freezer temps are you guys getting with your compressor fridge? I had seen some people complain about freezer temps only in the 20's. It is best if they are down in single digits, which my 3-way does well. OTOH, my fridge temps are a bit flaky, though a recent fan mod I did has helped a lot.

I think the warmer freezer temps may be do to the manufacturers intentionally positioning the temp sensor and setting compressor speed to increase overall efficiency and lower power use. We can change the temp of our freezer from the low teens to over 32* by moving the sensor around and leaving the freezer for open a bit or shut tight. If you look at the Danfoss compressor specs and cooling charts, the efficiency drops very quickly as the evaporator temperature gets colder.

We tend to like ours running on the high side, as we look at the van freezer as a short term storage place. Just below freezing, and the ability to do a slow defrost by moving the food to the front, leaving the door open a bit comes in very handy. We usually shop at least once a week, so to have food in the freezer for more than that would be very unusual for us. We do buy food that is frozen if possible, though, as it gives us some free frig cooling as it thaws out in there.

avanti · 03-28-2016, 10:25 PM

We have no problem getting single digit freezer temps if we want them. This would be at the risk of sometimes getting slightly frozen beer in the fridge, though. We generally keep it set so that the freezer is in the teens.

booster · 03-28-2016, 10:39 PM

Quote:

Originally Posted by avanti

We have no problem getting single digit freezer temps if we want them. This would be at the risk of sometimes getting slightly frozen beer in the fridge, though. We generally keep it set so that the freezer is in the teens.

That is a good point. The variations in freezer temp that I listed were with constant frig temp of 38/39*.

wincrasher · 03-28-2016, 11:42 PM

Yes, I can get it down in the single digits, but why expend the energy? Frozen is frozen and for what little fits in there, it's not like we are keeping food for weeks on end.

peteco · 03-29-2016, 02:34 AM

Right now I think my fridge is working OK but won't know for sure until hot weather hits. Glad to hear that the compressor fridges can get cold to single digits. That keeps the ice-cream hard.

Unfortunately the only compressor fridge that is a direct fit is the 5 cu ft one by Norcold. They are putting these in the Roadtrek 210 now. It would be good to hear how well they work. I'm not too keen on Norcold based on past experience.

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