Texas style refrigerator.....

[alanmalk]

Originally Posted by bborzell

The smaller freezer compartment and the larger cooling box operate via 2 separate evaporators.

If two evaporators exist, aren't they both subject to the same 90 F temperature? And therefor the same laws of physics?

[bborzell]

Originally Posted by alanmalk

If two evaporators exist, aren't they both subject to the same 90 F temperature? And therefor the same laws of physics?

We don’t know if the evaporators are of similar specification. But, we do know that one cools a much smaller volume than the other.

[alanmalk]

Originally Posted by bborzell

We don’t know if the evaporators are of similar specification. But, we do know that one cools a much smaller volume than the other.

Then if the evaporator to volume ratio stays the same for each box, and the ambient temperature stays the same for each evaporator, then it should be easy to achieve the same results for each box.

[John in Santa Cruz]

My 2014 E21 came with the RMD 8555, which when it worked was quite good, never had issues with freezing or cooling even when ambient temps were > 100F for multiple days. the 21 had a chimney vent on the roof for the fridge.

the problem with the RMD8555 is, its an Electrolux design and was made in Germany, Dometic bought Electrolux's RV fridge division, but then stopped supporting it, its almost impossible to get spare parts for it. Mine fried its controller for unknown reasons, so I ended up replacing it with a Norcold N2175 12V DC compressor fridge which was an exact fit for the opening. This fridge maintains 0-10F in the freezer, and 36-40F in the fridge part even in the hottest weather. It needs around 500-600 watt*hours/day of DC

[KirkB]

I'm going to throw in my 2 bits worth here. I removed and reinstalled my Escape fridge last year, so I have spent a fair bit of time thinking about what factors make these contraptions work to their max.

I don't think that absorption fridges in general have a 40° threshold for cooling from ambient. I think that each fridge model has been designed to operate within a specific climate class. I have an RM8551, the 4.3 cu. ft. model, baby brother to RM8555, climate class N. It's specs claim to be able to keep food cool below 7°C in up to 32°C temps, a difference of 25°C or 45°F. (And this might actually be true, if you don't dare open the fridge door!).

There are 2 cooling evaporators, they both use the same source of coolant, the condenser. The freezer section evaporator can maintain a higher temperature differential in warmer ambient conditions than the main fridge compartment. My freezer can be -10°C when my fridge can only chill to around 5°C, a much higher differential. According to Wikipedia, the boiling point of the refrigerant is less than 0°F/-18°C, so should be able to keep things chilled if there is a good supply of liquid ammonia coming from the condenser. My theory is that the freezer will chill, and if there is any liquid ammonia left, so will the main fridge compartment. You notice the lack of cooling in the fridge first.

The RM8551 specs say the 120V AC heater uses 135W. I checked the specs for newer Escape fridges a while ago, they are in the ~350W+/- range (I have forgotten the exact wattage number and model number), so you would expect these fridges to have almost 3x the cooling power of my little fridge. I think the RM855x series fridges are designed with energy efficiency in mind for a milder European climate, not for maximum cooling power.

The Wikipedia article that I reference below says that depending on the internal pressure in the refrigerant system, the condenser may only work up to 95°F/35°C. This also depends on having adequate ventilation behind the fridge to cool the condenser fins, that is why Texas fans are used, but depending on the coolant pressure, there will be a max ambient temperature, where the fridge will stop cooling if it cannot create liquid ammonia.

Edit: I put in a thermostat to turn on my fan at 40°C. It comes on frequently and stays on for quite a while depending on ambient temps. I also put in a thermostat for 50°C, which never comes on. So, I conclude that my condenser is normally over 40° if the fridge is maxed out.

Here are the essentials for your fridge to perform flawlessly:
- Adequate supply of ammonia vapour from the boiler (limited by boiler capacity)
- Adequate supply of liquid ammonia from the condenser (depends on ammonia pressure and cooling on the condenser fins)
- Sufficient insulation to keep ambient heat away from your fridge compartment and reduce the cooling power needed in warm ambient temps.

https://en.wikipedia.org/wiki/Absorption_refrigerator

[Iowa Dave]

Hi Kirk
That’s a pretty darn good analysis of the cooling ( or not cooling) abilities if these earlier model refrigerators. I say that probably because it lines up with what we experience with ours. I’m not too good with frustration or disappointment. As I stated our “work around” is the addition of an Engel compressor cooler unit which works very well. This leads to three outcomes that we can easily live with and eliminate frustration and the disappointment of warm or spoiled food.
1. Camping in cool weather, 75F or lower, big refrigerator works great
2. Camping in “marginal” temps 75F to about 82F, big refrigerator works ok, Engle guarantees cold meat, cheese, lettuce and most importantly beer.
3. Above 82 F. “What’s the Engle doing? “34F and steady as she goes”.
For me, a little more work or a little more money spent for the satisfaction of performance, convenience and yes, even appearance has always been worth it.

1. “Get a good one that will last even if it’s a little more money” from a friend of my dad when I was buying my first Case pocket knife.
2. It pays to look well ( sign in the barber shop when I grew up”
3. “You ought to look like something when you go down the street” from my Dad when I Blue Coral waxed his black Buick and many other cars for customers when I was a young teenager.
And that’s how I could afford the Case knife. Work

Have a great thanksgiving

Iowa Dave

[advenas]

When I ordered my 17B back in 2016 I got the Texas fan option. Basically it's a factory option from Domestic that turns on a small thermostat driven fan to help exhaust the heat from the back of the fridge on days when the temperature gets to 90 degrees or so. Seems to work fine as my fridge has always stayed plenty cool even on 100+ degree days.

[Escape_19]

Originally Posted by advenas

When I ordered my 17B back in 2016 I got the Texas fan option. Basically it's a factory option from Domestic that turns on a small thermostat driven fan to help exhaust the heat from the back of the fridge on days when the temperature gets to 90 degrees or so. Seems to work fine as my fridge has always stayed plenty cool even on 100+ degree days.

I wonder why Reace wouldn't have made this a standard thing for all refrigerators. It certainly would not have hurt anything to exhaust heat.

[advenas]

Originally Posted by Escape_19

I wonder why Reace wouldn't have made this a standard thing for all refrigerators. It certainly would not have hurt anything to exhaust heat.

If I recall correctly the Texas fan option was an added cost plus a special request to Domestic as the fan was added at the factory from what Escape told me. So I could see where Reace wouldn't want to add an extra cost or increase the wait for his refrigerator orders on every trailer.

[Vermilye]

It also caused some problems in the early Dometic DM2663LBX refrigerators. There is a notice above the refrigerator in my 2017 21C stating that the Texas fan switch (inside the outside lower refrigerator access panel) MUST be turned off before towing the trailer. Seems a thermal fuse would fail if the fan was on while driving - not an easy replacement...

[Iowa Dave]

Hey Jon
I’ve been meaning to check with you. How are you doing? how much snow did you get?
Have a happy Thanksgiving
Iowa Dave

[advenas]

Originally Posted by Vermilye

It also caused some problems in the early Dometic DM2663LBX refrigerators. There is a notice above the refrigerator in my 2017 21C stating that the Texas fan switch (inside the outside lower refrigerator access panel) MUST be turned off before towing the trailer. Seems a thermal fuse would fail if the fan was on while driving - not an easy replacement...

Interesting. Not sure what Domestic fridge I got other than it was the 4cu ft one. But I was expecting a switch for my Texas fan and Escape said it is fully automatic via thermostat control.

[rubicon327]

Originally Posted by KirkB

There are 2 cooling evaporators, they both use the same source of coolant, the condenser. The freezer section evaporator can maintain a higher temperature differential in warmer ambient conditions than the main fridge compartment. My freezer can be -10°C when my fridge can only chill to around 5°C, a much higher differential. According to Wikipedia, the boiling point of the refrigerant is less than 0°F/-18°C, so should be able to keep things chilled if there is a good supply of liquid ammonia coming from the condenser. My theory is that the freezer will chill, and if there is any liquid ammonia left, so will the main fridge compartment. You notice the lack of cooling in the fridge first.

Yes, this is the case because the evaporators are in series. The liquid passes through the freezer first and then the refrigerator.

[Vermilye]

Originally Posted by Iowa Dave

Hey Jon
I’ve been meaning to check with you. How are you doing? how much snow did you get?
Have a happy Thanksgiving
Iowa Dave

Doing fine, but will miss winter in Arizona. So far the worst snow was 1' and most of that is melted. Happy Thanksgiving to all!

[gklott]

Originally Posted by Rossue

…when ordering a 19 had the option to upgrade to the RML8555.
Perhaps the "Texas style" really meant the Texas

We had the original RML8555 in our 2019 E19. It was terrible. We live in Texas, and since 2003, we’ve owned trailers that came with Dometic absorption refrigerators. These Dometic refrigerators have never worked well in any summer weather where we travel. They were marginal during other seasons.

So we changed to a DC compressor refrigerator-freezer. It is the Isotherm Cruise 195 INOX refrigerator-freezer. We are so pleased with it.

The Cruise 195 has separate compressors for the refrigerator and freezer. After a long, hot Texas summer, and travel thru New Mexico, Arizona, and California, the Isotherm works.

While not the same as the ordering sheet “Texas-style”, we call our Cruise 195 our Texas-proven refrigerator.

73/gus

[Tosh]

My 21NE came with an Isotherm installed (by the first owner). When we had 105F weather here in Oregon, the fridge was able to maintain 40F set at 7 (max). Trailer was parked with southern exposure on the driver's side.


I think I'll be pulling the fridge out this winter so I can install better insulation in the alcove. Seems the thin insulation that's in there leaves a lot of room for improvement

[John in Santa Cruz]

Originally Posted by Tosh

My 21NE came with an Isotherm installed (by the first owner). When we had 105F weather here in Oregon, the fridge was able to maintain 40F set at 7 (max). Trailer was parked with southern exposure on the driver's side.


I think I'll be pulling the fridge out this winter so I can install better insulation in the alcove. Seems the thin insulation that's in there leaves a lot of room for improvement

what was the interior temperature in the trailer douding that 105F spell ? my Norcold N2175 compressor fridge is entirely ventilated inside, so ambient inside temps are what is sucking in to cool...

[stratos175]

I'm going to guess we have the original 8551 fridge. Hi Dave, not sure if you would remember but that was one of the first things you noticed in our 2014 21C when we met at the Davey Crockett Birthplace park rally a few years ago. I even reached out to Escape after you told me about this and their response was no they were not really defective so they would not replace and this is when Reece and Tammy still owned the company. We don't really camp when it's hot either and for the most part I would say the fridge cools well especially since we don't precool it at all. I hope it stays that way.

All the best for the holidays,

Steve

[Rossue]

Nope all Gen1 21's had either RML8555 or starting sometime in 2015 the two door RMD8555. Only the 19 had 8551 which was a particularly bad POS. When Reace got the swap approved by Dometic for RML to RMD, 8551 owners only got an upgraded door and weren't very happy at the time.

[John in Santa Cruz]

my 2014 21C came with the 8555 ...

ah, you can see it here...



freezerr on top, inside had clear blue plastic 'crate' shelves, and blue LED lighting, controls were exposed when you opened the fridge...