Looking at potential AC/DC replacement fridges for the Dometic RM8551 4.3CF, which I know many of you have, and which we also planned to add as an upgrade on our 17B.
Thetford really doesn't have an AC/DC model of suitable dimensions and capacity to do a direct replacement.
NovaKool (which is made nearby ETI in East Vancouver) does have two models that might work. The first one pictured below is the NovaKool R4500, which is 4.3 Cubic feet. It's cutouts are about the same as the ones for the Dometic. The second one is the NovaKool R5810, which has a higher capacity of 5.8 Cubic feet. It 'might' work, but it's about 1 1/2" wider than the Dometic RM 8551. In looking at just the photos of the 17B interior, there may not be enough cabinet width to play with.
Both models draw 4.4 Amps at 12V, or 2.2 Amps at 24V, so power consumption is the same. All of this is predicated of course on whether or not you can make that much power to make them practical for boondocking.
The link is the spec sheet showing the dimensions and models for all of the NovaKool fridges. There are some that may work (at least dimension wise) to replace the 6.7 CF Dometic RB 8555 as well.
For those of you who haven't been following the various threads about fridge types, remember that these are AC/DC ONLY -- no Propane involved.
In the interest of science, I think you should try one! Duty cycle is going to be really important for these. I wonder how much they run on an 80 degree day if well insulated when installed. Lots of assumptions to get at a number, but they really might be practical. I assume they transfer the heat out to the outside through an external vent of some sort instead of radiating to the ambient air in the living compartment the way our home fridges do. Wonder how much ambient temperature affects that process.
Both models draw 4.4 Amps at 12V, or 2.2 Amps at 24V, so power consumption is the same. All of this is predicated of course on whether or not you can make that much power to make them practical for boondocking.
[/url]
Yesterday was a bright sunny day in western Ma., my flat mounted 160w panel was putting out 6.5a at high noon. Comes out to 3.86a if it were a 95w, don't know what the max size is for the trailer you are planning on.
Being in Tx I'd expect you to do bigger. I mean better.
Being in Tx I'd expect you to do bigger. I mean better.
Sounds like you've been here!...lol
Seriously though, that's the kind of info I need. I'm thinking we prewire for solar, but have the connections terminate on the side of the trailer instead of the roof, and use 2 portable/movable panels we buy afterward.
__________________
"You can't buy happiness, but you can buy an RV. And that is pretty close."
Those 12/120v models do not need any external venting, IMHO. I have had the smaller models in smaller trailers, most are mounted low, below counter tops. About the only heat they create is similar to a microwave, thus a small vent on the side of a cabinet should suffice. They do make some noise while operating, similar to a water pump, a lot more than the propane models.
__________________
Jim
Sometime life gets in the way of living.......
I think you're right Jim, but since the vent would already be there, I assume it would help dissipate any heat from the compressor. As for the noise, I think you're right also, but these newer Danfoss German compressors are much quieter than the ones they put out a few years ago. Noisier than propane to be sure (anything is) but I don't think it'll be a problem for us.
__________________
"You can't buy happiness, but you can buy an RV. And that is pretty close."
Actually you would probably want to close those exterior vents, they let a lot of cold air into the unit that is not needed. Plus I'm not sure ETI will sell a unit without a refer.
__________________
Jim
Sometime life gets in the way of living.......
Actually you would probably want to close those exterior vents, they let a lot of cold air into the unit that is not needed. Plus I'm not sure ETI will sell a unit without a refer.
A good point. Maybe the manufacturer can let me know if any vents are needed. I'm going to try to convince Reace to install the NovaKool instead of the Dometic. Hey, he's done custom faucets, why not a custom fridge --
__________________
"You can't buy happiness, but you can buy an RV. And that is pretty close."
Yes, very similar to units I had, 2 side vents using 2" round vents, some have a small fan back there to move air. I do not believe o/s venting is needed with these.
__________________
Jim
Sometime life gets in the way of living.......
Yes, very similar to units I had, 2 side vents using 2" round vents, some have a small fan back there to move air. I do not believe o/s venting is needed with these.
Yeah I think that's right. As long as there is a lower intake and an upper exhaust of some kind, it could vent to the interior. Some of the smaller models are "self venting", i.e., they have their own enclosure for the ventilation built in to the fridge chassis.
The challenges I see, since I've been 'volunteered' to be a pioneer, are
1) getting ETI to agree to customize the cutout and install it
2) getting one to ETI
3) having enough solar to make it practical when there is no hookup
I have no doubt that if the above issues are worked out, these compressor fridges will blow away the absorption type in terms of performance - especially here in the heat of Texas.
__________________
"You can't buy happiness, but you can buy an RV. And that is pretty close."
You know, a really enterprising person could go ahead and buy the fridge, two large 6-volt batteries like ETI installs, and a couple of portable solar panels and try this thing out before committing to modifying a new Escape in production. Just sayin'.......
You know, a really enterprising person could go ahead and buy the fridge, two large 6-volt batteries like ETI installs, and a couple of portable solar panels and try this thing out before committing to modifying a new Escape in production. Just sayin'.......
Interesting. That same enterprising person could then haul the batts, panels and fridge to ETI when they drive up there for delivery, and have the even more enterprising folks there install them. That enterprising person better have a big truck to haul all that crap! Just sayin'....
__________________
"You can't buy happiness, but you can buy an RV. And that is pretty close."
Maybe we just need some customer success stories from NovaKool showing and describing successful installations. Then we would know real life battery/solar system combinations that would work if we ever wanted to take the plunge...I contacted them and asked for this info. Maybe they will jump on this thread to answer questions.
Just remember they are a little noisy, but being able to cool on a very hot day as well as operate while in transit are on the plus side. I would imagine the new ETI solar set up with dual sixes should handle the smaller unit.
__________________
Jim
Sometime life gets in the way of living.......
If the exterior vents are used there must be some way to seal the exterior side from the interior side for the sake of heating and cooling the trailer. Absorption refrigerator cabinets are designed to seal against the rear opening in the cabinet, but a compressor-based unit would not be.
If a compressor-based refrigerator is planned from before the trailer is built, it would be easy for ETI to just not cut the exterior vent openings, which would give a cleaner-looking exterior with two fewer areas to let water into the interior cabinetry.
If the exterior vents are used there must be some way to seal the exterior side from the interior side for the sake of heating and cooling the trailer. Absorption refrigerator cabinets are designed to seal against the rear opening in the cabinet, but a compressor-based unit would not be.
If a compressor-based refrigerator is planned from before the trailer is built, it would be easy for ETI to just not cut the exterior vent openings, which would give a cleaner-looking exterior with two fewer areas to let water into the interior cabinetry.
Yeah, that's what I was thinking after Jim's comments. A cleaner look and fewer holes in the shell -- I'm all for that. Also, the fridge would probably not require as deep of a cabinet. If the cabinet were purpose built for the compressor fridge, it might give you a few more inches of interior space and not stick out as far.
__________________
"You can't buy happiness, but you can buy an RV. And that is pretty close."
Some Power Estimates -- Escape 17B/dual 6 Volt Batteries/Compressor Fridge
An example: The 12 Volt fridge I’m considering has a draw of 4.4 Amps. This only happens of course when the compressor is running, and it doesn’t have to run all the time – just enough to maintain the temperature. But, for the sake of this example, if the fridge compressor ran for an entire hour, it would consume 4.4 Amp Hours (Ah). I know it won’t run continuously. Depending on the ambient temperature, and how many times I open and close the fridge, it might run on average about 40% of the time. So, again just for the example, I’ll say it has a 40% duty cycle. That means in one hour the fridge will use 1.76 Ah. In a 24 hour period, that means the fridge will use 42.24 Ah.
The dual 6 Volt batteries offered by Escape can provide an estimated 232 Ah of 12 Volt power. That means, theoretically, that if I were using them to provide power ONLY to the fridge and nothing else, and not recharging them by hooking up or by using solar, I could run the fridge for about 5 and a half DAYS. That’s not bad. But, I know that the fridge isn't the only thing I’ll be running off the batteries when I boondock. There are the lights and any other electrical accessory I might plug in, and any AC items I might be using if I have an inverter. Also, the inverter has an amperage draw that differs depending on how much wattage I am using. So, just for the example, let’s say that everything else besides the fridge uses about 40 Ah in the same 24 hour period. That means I could theoretically run the fridge and every other electrical item in the trailer for almost 3 days.
But, I haven’t taken into account that I will be charging the batteries, or at least offsetting their power drain, with solar panels. When I add that in, depending on how much power the solar system generates, I could boondock for an extended period of time with a regular compressor DC fridge.
Or am I missing something?
__________________
"You can't buy happiness, but you can buy an RV. And that is pretty close."
Linear Mode
