I started thinking out of the box about a new "cooling unit" yesterday. (In my previous FT I put a new Dometic in and even it did not work well after $3K - so I'm more than ordinarily unhappy with Dometics)
Then I wondered if I could use a small (16W x 13.5D x 12H) window AC unit like a 5000 BTU Frigidare FRA053XT7: $99 or so. Cut a hole for it in my Dometic's back wall and it vents heat to the outside as it does when installed in a window.
best, paul
There are a few wall units made today that look real nice and are very compact. You may have seen tham in HGTV shows from overseas. But, then what do you do for the freezer?
OK ... You are CRAZY. Charming and delightful ... but CRAZY. Just go with a residential fridge, and it is cheaper in the long run than your cockamamie AC unit!!! Hasn't Kathleen gotten you whipped into shape yet??? Crazy.
We've had a small refrigerator for some time, and it has a good freezer. We've also used the freezer section of the Dometic as a refrigerator! This is even more practical now that we've gone to the amazing Engine 2 diet (Google "Engine 2").
I once thought the cooling unit of the Dometic was not bad because it could freeze food in the freezer portion (and the problem in the refrigerator portion of the Dometic was bad insulation). But recently with higher temps outside, only 80, the freezer portion of the Dometic could not get below 45 during the day. Right now it's 40 with outside temp 60 and even if I took it down to 32 now it would be soon be 55 or more.
My big problem with many of the common AC refrigerators is they do not have the great insulation the Dometic does.
best, paul
:o So you think an AC will solve our challenges? I still like the idea of tossing out our present unworking refrig and purchasing one like we have in the park model .... just my humble idea!!!
I do not think my dometic has much more insulation than my samsung at home.
Well, I think the concept has merit but the specifics need tweaking. To my way of thinking there are some downsides to removing the Dometic, primarily the fact that it is a perfect fit, with matching panels and, for us, is of sufficient size. I also suspect the insulation factor is several orders of magnitude greater than any standard domestic refrigerator, open the door and compare it to a home model. While the domestic refrigerators are no doubt a joy to use, the appearance of them along with the hoops you have to jump through to keep sufficient juice (seem to recall most end up running the genset several hours a day, even with solar supplement, while boondocking) flowing to em are a downside.
Maybe consider retrofitting a Danfoss compressor/coldplate system into your existing box. These are most commonly used for marine installations (the air cooled condenser, not the water cooled). They are very high efficiency when installed in a well insulated box, are available in 12V, and I seem to recollect 12VDC and 120V AC versions, don't know if dual voltage without using the inverter is an option.
Lots of serious blowboat cruisers have experience with these, perhaps they will comment. Just a thought. Hopefully there won't be an angry mob of Samsung/Whirlpool proponents coming up the driveway with torches lit and pitchforks ready due to these comments. :))
Chuck
Chuck, no gensets going in our coach while Boondocking and solar does very well for fridge and all else.
We try to stay out of rv parks and when in one will dry camp. I did not invest in solar to be plugged in to a post. happy with it all.
John H
John, are you saying you can boondock on solar alone while using a residential refrigerator? That's impressive. Not having solar, I was basing my comments on some forum members commenting on their time at Quartzite, reporting several hours of genset runtime a day in addition to pv panels. I was kind of disappointed hearing that.
Chuck
Thanks for the Danfoss compressor/coldplate system idea, Chuck. Interesting, but expensive.
I'm surprised no one suggested a small window AC unit won't work. At only $99 or so they look pretty interesting. Plus you end up with a refrigerator with a perfect fit.
Come May/June I'll have to look at getting the cooling unit off our Dometic and seeing if a window AC unit makes any sense. Or just get a common domestic refrigerator.
best, paul
Chuck,
We ran our generator in the evening and an hour or two in the morning at Quartzsite, not because of the electric fridge. It is our style to have TV, two computers, two Directv DVRs, router, floor heaters, lights etc in the evening. We usually kept a computer with Internet on during the day.
Our fridge does not draw a lot of battery when on inverter. We always ran our generator the same way when we had a propane fridge.
If we turned off our electronics, our solar would do fine keeping up with fridge electric demands.
We installed an electric fridge for more cooling, more space and no flammable leaks and it has served us very well. John has the same fridge and does not know what a shore power cord is and only uses his generator to keep his front wheels on the ground.
Paul, you are crazy. I thought of a different word, but didn't want to be impolite. A window unit is designed to be installed level so any condensate will drain properly. Will your coach be level at all times like permanently parked never to move again? Does the $99 window unit have provision to prevent icing of the evaporator? Operating normally they don't get that cold, but blowing into a confined space it might freeze up. You could install a switch to turn it off when that happens like in the middle of the night, so you don't have to open the door letting in heat to do that. If it does work with out freeze up, then the hole you have cut in the back of the refrig will rapidly let in heat, so it won't be off for long. How quiet is the $99 window unit? Will you like the noise? Are you thinking your refrig is about to die? If so, look for a sale on a refrig that fits. Don't forget you will have to remove the old refrig to remove the cooling apparatus so you can cut the hole for the window unit. Will it blow into the freezer compartment or the refrig compartment? Will you be doing this yourself or paying someone to do it? How will this affect the resale value of your coach? I have sawed window units in half to make central ducted air, but this idea is just plain stupid. I hope you didn't suggest this just to jerk us around. Would be a good one for April 1st.
Paul, is your refer the original installed by Foretravel or a replacement?
I replaced the cooling unit of my Dometic 7832 in January, 2012 with a new unit from RVCOOLINGUNIT.COM. Cost was $1115 delivered. I rebuild some of the door seal and installed thermometers in both refer and freezer. It required removing and reinstalling four times to get it correct - not an easy job. In my opinion, the installation instructions are ineffective and I ended up using very different techniques to obtain a perfect seal between the cooling unit and the refer box. It now works very well, maintaining 3F in the freezer and 40F in the refer up to 95F. If your freezer is not freezing, it could be an inefficient cooling unit, or a partially plugged chimney, a dirty burner, a dirty gas orifice, or freezer/refer air leaks.
Will you be home this weekend? I will be at NAF for the "Blue Angles" show from Tomorrow to Sunday and could stop for a visit.
My CA cell is 760-587-0321.
Funny and almost true. Barry and Cindy dropped in to see us in the "Resort" in Mesa where we spent a month with friends and he was surprised to see us NOT hooked up to that post!!
Electricity was extra there as I think it is in most places in PHX, and we did have to buy power for 2 days as Ruth was doing a lot of baking for a dinner we were putting on for the 4 friends so the solar could not have kept up with the demand ( and we are aware of the times this will happen) Our bill for that was $7.67, so Yes Chuck it does work and my Batteries are getting the right charge all the time. A person just has to do a little changing of lifestyle and I repeat again we do not like or use a/c. We do not usually sit inside the coach if it is hot, go find shade or put a fan on.
John H
Thanks, Wyatt.
Yeah, I took your advice and removed one of the finned areas inside the Dometic. I'm not impressed with the 'connectivity' between the cooling unit and the fin plate.
I have no idea whether the refer is original or not.
We'll be around. Call first 510-386-7849
best, paul
No, Jerry, I didn't suggest an window AC unit to jerk anyone around.
And I may be crazy but I'm not stupid. I learned a long time ago that the only stupid question was the one not asked. That was the context of my question. I find I learn a lot by asking questions.
I was surprised to receive so little technical input, until yours. Thank you.
But I had already figured out my idea would not work after reviewing several compressor-based cold plate cooling unit systems. They clearly demonstrate what is needed, and I implied by analogy that an AC unit would fall short. But that doesn't mean my idea was stupid. And Chuck's suggestion about cold plates was enough to lead me to understand my idea would not work.
Compressor-based cold plate systems have some nice plusses in a Dometic application:
They allow the Dometic exterior to remain as is.
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Their negative is their cost.
But I recommend someone with a larger budget than mine consider a compressor-based cold plate for their reworking of a Dometic. One even claimed to work on battery only after batteries are fully charged.
In future, Jerry, you might take more time thinking of the right word. You also might be on the alert for those times when you characterize someone's ideas - especially someone you don't know well. Even the ideas of those you know well, like a spouse... Voluntary characterizations are often wrong and reveal more about the characterizer than the those characterized.
Something like. "Your idea won't work, Paul, and here's why," is more constructive.
best, paul
Wyatt,
You're an old hand in this area of CA but I wonder if you know the best place to see the Blue Angels perform. They put on an entire show last week at 8.30a and 1p and we went and really enjoyed it.
If you want to see the Blue Angels ONLY, the best place to see them is OUTSIDE the NAF. We were as close to the end of the runway as you can get. And they flew several stunts along the line of the runway. Bring ear plugs...
Let me know if you need directions.
best, paul
Looking at your experience with a new cooling unit, Wyatt, I realized another plus for compressor-based cold plate systems:
The cold plate is INSIDE the refer. Once inside with copper tubing connected, a lot of insulation could be put on the back of the Dometic.
best, paul
Hello Paul and others,
I'm late to this discussion but after reading all, thought I'd add some thoughts. Paul, in the last post you hit on something I had wanted to add to the discussion: insulation.
I'll begin with that. If anyone is considering adding insulation to the refrigerator, consider vacuum panels. Costly but very efficient. Last time I researched this, they were approx. R20-R30/inch. Common foams and store bought insulation is usually R5-6/inch. So, if you wish to make the investment, it is reasonable to quadruple your insulation value over std. materials.
I mentioned cost and again state, google vacuum panels and see what is out there if interested.
15 yrs. ago, I was building my boat for a circumnavigation and cost for materials was no object/all labor was done by us. Vacuum panels I bought then were the first ever produced/using Aerogel/ by Owens Corning and procured from Kevin/Alston(?) owner of Glacier Bay Refrigeration. Those panels/to cover the exterior of a 12 c.f. refer/frzr. cost me $3600. but they were R-75. That is/was equal to 15 inches of store bought insulation. (on a boat you do not have 15" for 'anything') The simple idea was: No losses ? then no need to run some system to replace them. We ran on solar/no generator so efficiency was the goal.............yes, at any cost.
It's a long read and only informative for anyone wanting indepth review of such an installation.
MEMORY ROSE: Refrigeration (http://memoryrose.blogspot.com/search/label/Refrigeration)
however, what I'd like to add, besides looking at insulation possibilties, is that Chuck was right on, suggesting holding plate systems. The wonderful aspect of them is that you can produce energy "when you want to!" and then coast along with the energy stored inside the cold plates. Wonderful for solar applications, or run times on engine-building up batteries. The work just fine when plugged in too. I ran my cold plate system on automatic normally, but when conditions warranted, I only turned the compressor on when i had a good source of power, like engine on or great sunlight, or plugged in somewhere. many options.
Search marine applications online if intersested. Technautics is one good company. i bought my air circulating fans from them and they last. cheap but efficient. Other systems out there also use the Danfoss compressor and work.
The only negative of our refrigeration options is that on a boat, most refrigeration systems are Top Loading/so when you open the lid, no cold air drops to the floor. In an RV, air drops out when opening the door and this is inefficient.
Thanks for sharing. It's an interesting read.
You'll have to go 'slow-ly-er' for me on the above. I think 'holding plates' and 'cold plates' might be the same thing.
But running with the compressor off is not clear. I think what might be the case is running the computer fan in the box to distribute the cold from the plates is normal refer control. The compressor may or may not be needed at the time.
best, paul
Gosh Paul... I just spent 30 minutes writing a reply to you and my computer did a 'blink' and all was lost! I'm going to rethink what I wrote and write it up offline then copy/paste/ try to post it again. sorry. ron
hope this flies!
--------------------------
Hello Paul....again ;)
OK. Holding plates are Cold plates...you are correct. They are made of galvanized or stainless steel material and usually thinner than 3" thick laptop sized units filled with salt water or anti-freeze so they freeze up at a lower temp than water. (often less than 1/3", but the 'thinner they are the more often the compressor needs to chill them down!!! IF you have room for thicker units?? then the OFF time for the compressor is longer!)
When we were kids, the local ice cream truck had lots of them inside.. made by Dole Corp.
It's like putting ice in your cooler. Ice at 32 deg. Can keep food near 40.
Holding plates at 26 degrees can keep you icebox(OK how old are we) 'comfortably' at 40 or less.
Holding plates at 16 degree solutions can keep your food at 26.
Holding plates at '0' zero... can keep ice cream frozen(fats and oils do not freeze easily)
It all depends on the additives in the solution!
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The 'fan' I added(first used Radio Shack cheapo's but they did not last) keep a continuous flow of air around the food/pulling coldest air from the bottom of the space and recirculating it over the top of the food. Home units do the same...I think.
Sorry but you just got the abreviated version. ;)
Thanks a lot Memory Roads.
Very kind of you to take the tme and trouble.
best, paul
Paul,
I apologize for getting you upset and I didn't mean to imply that you are stupid, just that idea, which you must have had doubts about from the beginning from the title. It's really easy to say something on the web that you would not say person to person, and once the send button is used it is there forever. Thanks for the advise on how to be tactful, which I was not.
Jerry
Your comment speaks very highly of you, Jerry. Thank you.
We've all send letters that should have been burnt.
And in this day it's all too easy to hit "Send" without reading and reflecting on our email.
I'd be lying if I claimed I've never done so.
My very best to you, Jerry.
I admire Paul's spirit of innovation and would like to mention one other possibility for retrofitting the existing Dometic at minimal cost. How about transplanting the guts of an apartment sized refrigerator into it? One of the units with the rear mounted condenser coils.... Be some tricky silver soldering but I've seen folks who could readily do it.
Chuck
Thanks for the kind words, Chuck.
I'm pretty close to innovating in a different way.
I think I'll go with cold plate technology. The 11.2 cu ft here:
Sea Freeze of America - Price List (http://seafreezeinc.com/price.shtml)
looks good to me.
We'll lose the under fridge storage are but gain a 10 inch wide storage floor to ceiling area to the left of the refer. This is even more convenient than the back breaker under the refer.
best, paul
PS> My soldering days were a long time ago in a land far away back in Ohio in the 50s ;o)
Paul, If you have time, research, marine refrigeration, holding plate systems, Danfoss systems, air cooled, remote installations etc. and work it hard.. and vary the terminology...............like Danfoss holding plate, or remote installs of compressors. etc.., there are many forums that have very good info but stick to the last 4 yrs. or so, as technology has improved.
Sure, Ebay or another might have a deal if you are into picking up components. Good Luck amigo.
Thanks MemoryRoads.
best, paul