Alternative power for propane refrigerator

[WindriderNM]

I am currently using a propane refrigerator. I would like to try to use some other fuel, possibly solar using a parabolic dish or a trough collector and some kind of heat transfer fluid. I am also thinking about using vegetable oil or bio diesel but am worried about sut accumulation. Does anyone have any ideas on this?

[Bruce S]

Parabolic could quickly get too hot or using a trough type could be hard to control if it's your first try.
Veggie oil versus Bio-D. Cut away from the chemicals and go straight for using WVO. Soot cold be a problem, if you run it too dirty.
Will still take some trials , do you already have WVO you can try?
One thing is that you will need to have a clean route to the area that needs to stay hot. One way to keep soot down would be to use a wick from a Oil Lamp cut it short and keep it cut short. This will keep the smoke down to a minimum.
Any crud in WVO will show up as soot.
How much propane does it currently use per week or month?

Bruce S

[Volvo farmer]

What kind of propane refrigerator? Danby? Servel? Norcold?

[WindriderNM]

It is a  Norcold, I also have two Domestic and one Servel that I am planning on experimenting with. I think one of them needs to be recharged does anyone know where you can get the gas/liquid mixture? One of the Domestics almost worked it started to get cold  the next morning and it was no longer cold and the service light came on. I have the other Domestic upside down right now and will try it in a few days. the Servel leaks around the gas control box so I will start with it.

A 20 pound propane tank lasts 2 to 3 weeks.

[kurt]

you can get the gas from a refrigeration wholesaler but you need a refrigeration license rated for ammonia refrigerants for instance i have a refrigerant license for refrigerants that you would find in a normal refrigerator but my license does not extend to ammonia refrigerants that is another license.  here our local community college offers the courses and testing for the licenses.

i know a guy who will probably comment to this thread eventually that owns a old kero burning servil fridge and it used the same wicks as the Aladdin lamps. that is a special wick designed to put out as much light as a 60w incandescent bulb in one of those lamps.

[scottsAI]

The best solution is to sell propane Fridges.
Energy efficiency is very poor.
http://www.oasismontana.com/refrigerator.html
Propane use is 1.1 lbm per day = 21,500BTU is equal to 6.298kwhr per day.
Average Fridge today is 1.400kwhr per day. Better can be found.
Several posts here about adding insulation to Fridge improving this number.

MI winter receives 3.5 sun hr average during the winter.
1400/3.5 = 400w solar panel to run this Fridge. (really need something bigger).
Many missing details to make this work. (numbers are a simplification)
Considering solar panels cost: www.sunelec.com
Best is $1.20/w + ship.

Electric Fridge run on propane generator will use half the propane. (If done right).

Sell your propane fridge, buy a new 120vac electric fridge and solar panels with money left over.
Hunting camps love propane fridges. Use a propane generator for backup!

Have fun,
Scott Beversdorf.

[bj]

  One thing to check on the one that worked then quit---is it level?  I know the Dometic in my 5th wheel is a bit fussy.  Does exactly the
same thing.
  Just a thought.

[Volvo farmer]

I gotta agree with scottsAI here.  I'm beginning to see 1.1-1.2KWHr/day refrigerators for sale in the big box stores for around $500. This is for a nice 18 cubic foot box, not one of those little 10 CF Norcolds.

Check this out. A $450 home depot fridge has beaten the 1.0 KWhr/day threshold.
http://www.homedepot.com/Appliances-Refrigerators-Freezers-Top-Freezer-Refrigerators/h_d1/N-5yc1vZ1xg6Zarge/R-202212438/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

http://products.geappliances.com/MarketingObjectRetrieval/Dispatcher?RequestType=PDF&Name=197D8238P008.pdf

If you really have electricity to burn, the Norcolds/Dometics usually will run on about a 300W heating element that is sandwiched next to the burner tube.  I think it would really be a heroic effort to try and make a reliable burner that works on anything but propane or natural gas.  The flame needs to be modulated up and down to keep the temperature right and that ain't easy to do with any sort of liquid fuel.

I also have an EPA license for HCFC refrigerants but I have never heard of one being needed for ammonia based systems. I do know that the pressures involved are quite substantial and sealed system repairs are extremely difficult. Definitely not a DIY type of repair, if you ask me.

It used to be that if you wanted to live off grid, you really needed to consider propane refrigeration, but with the price of solar panels dropping and the efficiency of cheap refrigerators increasing, I believe that it truly makes sense to go with an electric refrigerator nowadays. And once you have made the investment, there is no recurring bill like there would be for propane.

[bob g]

around here ammonia is tightly regulated, apparently it can be used to make meth and i have heard it is also possible to use it
in the manufacture of things that go boom.

i always figured when it came time to do absorption chiller/cooling, i would just contract out the charging portion of the project.

that makes sense to me, much like hiring a bulldozer rather than buying one for a one time or very infrequent job, or a motorhome
rental for the yearly vacation rather than owning one just to sit around for 51 weeks a year.

bob g

ps,  volvo farmer:

thanks for posting the link to the fridge from homedepot
i guess it is time for me to go take another look at whats available today
that is a nice size unit for the power consumption, and it would fit my needs quite well

[ghurd]

Check this out. A $450 home depot fridge has beaten the 1.0 KWhr/day threshold.

VF,
Do you figure the "Digital Temperature Control" will run on MSW?

I can imagine a stand alone system where the fridge, panels, battery and controller, combined,
cost less than the PSW inverter. 
G-

[Volvo farmer]

VF,
Do you figure the "Digital Temperature Control" will run on MSW?

I can imagine a stand alone system where the fridge, panels, battery and controller, combined,
cost less than the PSW inverter. 
G-

I just typed that model number into Sears parts lookup. What I see is a regular capillary-tube type cold control with old fashioned contacts.  It does appear that the defrost timer uses relays and a printed circuit board though. It has always been my understanding that electronic things that have to keep time (such as a defrost timer) don't work well with MSW.

By the looks of the defrost timer, it appears that a $20 motor based-defrost timer could be easily substituted, probably negatively affecting efficiency though.

I'm just not a big fan of MSW, maybe it would work with this fridge, maybe not. My opinion is if you're going to live off grid, just pony up and buy the $2000 inverter and be done with it.

Think of it this way, a Danby 8CF propane refrigerator runs about a grand and uses 8 gallons of propane a month. After a year you'd be $500 ahead on the fridge, $250 ahead on propane, and 10 cubic feet ahead on cold storage.  In ten years, you'd be $2750 ahead, enough to buy a nice inverter and a couple hundred watts of solar panels.  A ten year payback, without massive government subsidy, is pretty good in today's world.

[ghurd]

Agreed about the inverter.

I still like the DC Sundanzers.  With current solar panel prices at rock bottom, the entire system is less money than a big PSW inverter.
But I honestly would NOT want to use a PITA chest style fridge at home.
G-

[DanG]

I've got two Swedish built refrigerators (one 2-way, one 3-way) that I know work well, but they are getting some age on them and the interiors and trim are beat up, plus they are heavy as boat anchors so I'm wondering if I can build a cold box to re-purpose the cooling plumbing into. Without leaping to a Danfoss 12/24V compressor the absorption-cycle continuous propane or 300w electric draw sure makes RE or RE assisted cold storage attractive.

The ammonia cycle refrigerators work on surges that can take 3 or 4 four hours to start - If going with direct solar (without storage) as primary power input getting a pre-dawn heat cycle going with a back-up fuel and then switch over to PV dumping into a resistor would sure stretch a gallon of propane and get the cold source going for the days door openings and food additions - and doubling or tripling the R value of the insulation would better let it coast overnight until the cycle started again.

[Radbert]

          This is really useful for me and for my family. We are using propane refrigerator and this alternate power really saves a lot. I think we will continue using this so we can we save a lot.



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[MetricCook]

Would love to know what the actual temperature of the heat to make the propane frig run. Having a frig run of the sun would be fun, but what you do at night?

Sundazers, are great for freezers, but as a chest refrigerator I am starting to have doubts about. There is a build up of humidity/moisture I simply can not get rid of, thus mold. The company has not answered a favorable solution to the problem. Maybe, the unit is only for desert conditions/places.

[dnix71]

MetricCook Where is the moisture buildup? My upright Engel slowly fills with water from condensate. I simply take a towel from time to time and wipe it up. There is no "fix" other than that unless you want a hole in the bottom. If you do that, the fridge inside bottom must be concave and the fridge somewhat level. You will leak cold air and critters will be able to come up the drain tube into the fridge.

I considerd drilling a hole and adding a drain tube, but decided not to. Engel's are very well designed and made. I figured they must have tried a drain and it caused more trouble than it was worth.

[SteveCH]

I am all for DIY and experimentation and so on. But if you want reliable, easily useable/no-brain-damage food refrigerating and freezing, you just can't go wrong with electric appliances and photovoltaics. Well, if you don't have a pv system set up already, don't read further. But if you do, it is trouble-free. We've been in our off-grid home since 1985, and after a few years I gave up and bought a 12 v. fridge and never looked back. Zero trouble or repairs since then. In fact, three yr. ago I added a 12 v. freezer and we love it. Again, zero trouble. Very efficient and you plug them in and forget them.

A friend of mine near Santa Fe, NM has a propane fridge with a freezer compartment in it. He spends too much [I think] on propane and the freezer part doesn't work all that well. The thing does work, however, and keeps his stuff cold. I am just allergic to spending so much money on propane. He has 12 v. pv running the rest of his home but he is allergic to spending money on an electric fridge [his propane fridge cost him next to nothing when someone wanted to get rid of it]. However, he has, after some years, passed the point where his propane bills are more than the cost of an electric.....