Compressor fridge retrofit

[the5reeds]

Has anyone done a JC Refrigeration (Dutch Aire) compressor fridge retrofit to their existing Dometic fridge? My big question is clearance out the side, as the compressor bottle may extend past the outside of the trailer

I am having issues with my existing 3 way (19) and have decided to do a conversion to compressor. My fridge is a DM2663LBX. I have lithium and solar and have owned an RV with a compressor fridge and liked it, so we really don't need to discuss pros and cons

I am also looking at Novacool to see if they have a fridge with a similar size, but I don't think they do.. The JC Refrigeration option will be cheaper and I would not have to take it out of the trailer.

[Brian B-P]

Originally Posted by the5reeds

Has anyone done a JC Refrigeration (Dutch Aire) compressor fridge retrofit to their existing Dometic fridge? My big question is clearance out the side, as the compressor bottle may extend past the outside of the trailer.

That's an interesting option!

I looked at their general conversion web page, and one of the Dometic models, which notes:

you will need approx. 7 3/4″ from back of fridge to outside of side vent

Maybe someone can take a ruler to their 19' for comparison.

[the5reeds]

Yeah Brian, that's the issue. On my 19 that clearance on about 6 1/2", so either that outside vent cover will have to be modified, or the fridge pulled out a bit with extra trim or both

[Viajante]

Brian B-P,
Will you please enlighten us as to how an Amish cooling unit actually works and what it runs on? Doing a search on ACU provides no technical information other than some references to helium. Thanks.

[the5reeds]

You remove the absorbtion cooling unit from your existing fridge and replace it with a compressor cooling unit. It runs on 12v.

[Brian B-P]

Originally Posted by Viajante

Brian B-P,
Will you please enlighten us as to how an Amish cooling unit actually works and what it runs on? Doing a search on ACU provides no technical information other than some references to helium. Thanks.

The "Amish cooling unit" originally just meant a conventional absorption system built in the area where Amish people live, trading on a perception of high quality. The design and refrigerant materials used are the same as the original.

JC Refrigeration now offers a few different cooling unit replacements under the "Dutch Aire Amish" branding:

• they may still have a completely conventional direct replacement
• there is an upgrade to dual absorbers listed as "Upgraded Gas/Electric Hybrid"
• "Upgraded Gas/Electric – Helium Charged" which means that it is still a conventional absorption refrigerator (with dual absorbers) but with the hydrogen replaced by helium in the refrigerant mixture; this is actually somewhat common, with some complete refrigerators (including some Dometic models) coming with helium when new
• replacement of the absorption cooling unit with a very different compressor-based cooling system, which is what the5reeds is planning

The absorption cooling cycle is bizarre, especially in the version used in RVs. It depends on heat flow as a refrigerant gas (ammonia) is absorbed into and boiled out of a liquid (water) and normally it requires a liquid pump (not a compressor) and that is how it used in industrial systems. In an RV to avoid the need for electricity to operate the pump a very low boiling point gas is added to the ammonia, bringing the boiling point into a range that lets the system operate with the fluids moving by convection, without a pump (because it's all at the same pressure), but with a complex flow in overlapping loops; the ammonia goes in a loop including the boiler, while the low boiling point gas doesn't go through the boiler. This is described as a "single pressure absorption refrigeration" system in Wikipedia.

Hydrogen works well as the light gas, so a normal RV absorption refrigerator contains water, ammonia, and hydrogen; helium can replace the hydrogen but it doesn't work as well (can't produce as much temperature difference). Helium is perhaps safer and might be less likely to leak out than hydrogen. If you knew that your ammonia/water/hydrogen cooling unit failed because it lost its hydrogen charge that would be a reason to consider helium for the next unit.

[Donna D.]

Manufacturers of the Amish RV Cooling Unit: https://jc-refrigeration.com/

[Vermilye]

Here is a YouTube video

of an installation on a Dometic refrigerator. I don't remember where I saw the link to it posted, but it might be useful here.

[Brian B-P]

Originally Posted by Donna D.

Manufacturers of the Amish RV Cooling Unit: https://jc-refrigeration.com/

Yes, that's the company with this specific range of replacement units, and the same website as I linked earlier. Of course, anyone could use "Amish" in their product names, so an "Amish RV Cooling Unit" could potentially come from anyone.