Propane and Compressor Refrigerators, by Tunnel Rabbit

This is a brief analysis of propane and compressor refrigerators in long term grid-down appplications.

In Northwest Montana life has not changed radically during the Coronavirus lockdown, and there are plenty of used freezers, and fridges available on Craigslist.  However, demand for propane refrigerators is on the increase as there is marked rise in interest in self-reliance.  If nothing can be found in your area, then be willing to travel to buy a used propane refrigerators before they are gone.  These are expensive and hard to find. At the least, these can preserve meat while you jar it up, and provide back up and off grid refrigeration.  These will become increasingly expensive and harder to find as the current situation evolves, so this might be a good time to check in your area and use the funds to buy a propane-burning absorption refrigerator instead of standard freezer, 120AC, or 12VDC compressor type refrigerator, that may or may not be still available in your area, when the propane option might still be. JWR Adds:  One option is contacting large recreational vehicle (RV) and fifth wheel trailer dealerships. They often have used RV refrigerators available with cosmetic issues (typically just scratched or dented doors) that make them very affordable.

A typical used 10 to 12  cubic foot propane fridge might run $700 or more. A new one is twice that price, or more.  And full size propane refrigerators are like hen’s teeth. New refrigerators of the standard 10.5 cubic foot size start at $1,200, and for the largest size, $2,500 new.

The typical 10.5 cu ft. size, set to the lowest temperature for summer operation, will use no more than three 20 pound propane bottles per month during the summer months, or to be precise, consumes 1,200 to 1,600 BTU per hour on the highest (coldest) settings, depending on the model. The lowest setting (higher lower temperature) is often one half to two thirds of the highest consumption or stated BTU rating. The service manual should provide the lower BTU rating.  The highest consumption rate or rating, is recorded on a plate at the bottom of the front door, or in the back lower portion near the burner.  One pound of propane contains 22,000 BTU, and there are 4.2 pounds of propane per gallon. Divide 22,000 by the BTU rating to determine the number of pounds of propane used in one hour, then multiply by 24 hours to determine the amount used per day.

Propane Storage

For remote retreats that cannot be accessed by a propane delivery truck, you won’t be able to use a typical  domestic 200 to 750 gallon propane tank. You will need to use smaller man-portable tanks. If you can handle the weight, a 100 pound bottle is preferable to the 20 pound barbecue tank, as it use avoids frequent changes of tanks and start ups by one fifth, or from every week, to only every 6 weeks or so. 40 pound bottles are harder to find used, and more expensive, yet the convenience of these in this application might make it worth the extra expense.

All figures are estimates adequate for comparative purposes. Ambient temperatures, the quantity of food stored, the refrigerators rating, and selected internal temperature setting are the important contributing factors in fuel consumption. To increase efficiency, or reduce propane consumption up to 30% or more, use insulation attached to the outside in some way. An aluminized coating on the exterior of the insulation helps a great deal, even it’s only aluminum foil, or a mylar blanket cut to size, or foam board with aluminum foil that is usually available at building centers.  To increase efficiency further, use a small fan to circulate air to cool the ‘fins’ on the back side.  A computer type “muffin fan”, or other small fan can also be used inside to circulate the air, and move warmer air inside passed the evaporator fins that are usually located in the freezer box.  Refrigerators and air conditioners require adequate temperature differentials to cause internal system gases to expand and condense.  A fan assist with that process.

Propane refrigerators need not be vented if use inside a home, but should be vented if used in a small space such as an RV.  A tiny burner provides the heat that boils the gases inside the tubes located on the backside.  There are no moving parts to break.  However, over time, usually measured in decades, the hydrogen gas can escape rendering the fridge inoperable.  Periodic maintenance is also required once, or twice a year to ensure reliable and efficient operation, and the coldest temperatures possible. Usually the chimney needs to be cleaned, and the burner checked for a nice blue flame.  Sometimes the tube feeding the burner and the tiny orifice that regulates the gas needs to be clean out with a solvent to remove oil deposited by the propane gas, perhaps the filter changed, or the regulator from the tank replaced or adjusted, and the cooling fins in the back dusted off.  Most of the maintenance can be handled by the average person who can follow the instructions from a service manual.  JWR Adds: For safety, just leave any repairs that require getting into the ammonia or hydrogen piping up to someone who is qualified!

For longer term sustainability, purchase the smallest propane refrigerator that meets your needs.  I am about to trade a larger propane fridge that sold for $700 on the second day advertised, and accepting for two smaller dorm/RV sized ones as trade-ins, for a $200 credit.  These are 3-way propane refrigerators that also run on 12VDC and 120AC.  This provides redundancy in terms of power source options and doubles the number of fridge available, and each uses approximately one third the propane that a 10.5 cubic foot fridge does, or only about 600 BTU for a 3 cubic foot dorm sized, versus 1,600 BTU for the mid-, or standard-sized variety that are about three times the size. A small RV fridge can usually run for a month on a 20 pound tank during the hottest part of the summer, where as the large 10.5 cu. ft. needs 3 times as much. As ambient air temperatures decreases, fuel consumption will also decreases.

The smaller 600 BTU fridges provide space to preserve several meals. If more refrigeration space is needed, both smaller fridges can be run. We are setting ourselves up for the long haul and should strive to understand and use resources wisely. This is all the cold food storage space that one or two persons actually needs, and it is a luxury item from my perspective. Propane is inexpensive right now ($1.38/gallon around here as of this writing), yet storage costs and fuel consumption can be reduced by one third using the smaller 600 BTU refrigerator, or we can have three times the capacity for the long haul without propane delivery. A 100 pound bottle can run one of these RV, or dorm room-sized fridges for about 6 months, or longer if it is well-insulated, and until the colder seasons arrives again, making a refrigerator unnecessary. A 10.5 cu. ft. refrigerator that is rated at 1,600 BTU would require the equivalent of three 100 pound tanks (24 gallons) during the warm-to-hot six months of the year.

Insulating these fridges reduces the propane consumption by at least by 30%. This means a 10.5 cubic foot fridge that usually uses three 20 pound tanks a month or three 100 pound tanks a season, would then only need two 20 pound tanks a month, or two 100 pound tanks. During the winter when a refrigerator is not all that necessary up here in the frozen end of the American Redoubt, blocks of ice made just outside the door can turn a fridge into an ice box. To store items that need to remain cool, but not frozen, use an ice chest outside, but be certain that the bears are already in hibernation.  A super-insulated box full of frozen items, can remain cold into early spring, weather permitting.

One Forced Quick Expedient

One of my freezers failed in mid summer. So I moved about 100 pounds of frozen trout in to a large plastic bin with lid. No ice was added. Two layers of foam board were placed on the floor, and the box on top was then wrapped with several layers of R-11 fiberglass insulation around, and over the top of the box.  To complete this field expedient ice box, it was then covered with a large sheet of mylar from HVAC heating duct that reflected radiant heat from the barn’s uninsulated metal roof.  It had to be protected from critters in a on old barn that became very hot, approaching 100 degrees during the day. But the fish stayed icy for more than a week while it was canned up.

If one does not have a freezer, frozen or unfrozen meat can be stored temporarily using ice in a super insulated box or container in this way. Placing into the ground would increase storage time as well, and can double as a root cellar.  This would work if your freezer failed, or as a method that can be used to extend storage of cold items into warmer spring months by several weeks if improvements were made, and as a method to reduce propane consumption, yet further.

Testing Used Propane Refrigerators

Some propane refrigerators in good working order can also be adjusted cold enough to freeze the entire contents.  Ask the person selling a propane fridge to freeze a cup of water before you come out to look and possible buy a used propane fridge.  If the freezer portion cannot freeze a cup of water, then do not buy it.  If they want big bucks for an old fridge, the least they can do is freeze a cup of water if you do not have a thermometer to test. The refrigerator part of the interior should be at least 40 degrees or colder.

Of course this might be a good time to also consider the newer compressor type refrigerators. This technology is now well proven, and popular for use in recreational vehicles (RVs).  These are expensive as well, yet lend themselves to be powered by a PV system. With enough panels and no batteries, these fridges can freeze items during the day when the sun shines, and thaw at night when the sun does not shine. If storage batteries are used, instead of consuming propane, we will be consuming storage batteries every few years.

Relative Costs

Buying a propane fired unit is about the same price of a bank of two Trojan T105 batteries, and additional PV panels to charge them up that might cost $700 for the part of a small system, and last 3 to 4 years, or as long as the batteries last.  The cost for this small PV system will run my 3 cubic foot propane fridge that cost less to purchase used or the same new as a Dometic compressor fridge, for 21 summers if one could store that much propane.  The math is simple:  $700.00/$1.38 = 507 gallons of propane X 4.2 pounds/gallons = 2,129.4 pounds divided by 100 pounds = twenty one 100 pound tanks. And batteries will be harder to come by and more expensive in the future than propane. There is no longer any lead being mined in this country. Most of it is in China.

One 100 pound tank would run the 3 cu ft. fridge for 6 months, from spring into fall.  Extra insulation can also be added to the outside to improve efficiency, and reduce consumption another 30%.  Propane fridges are proven to last for decades, and their fuel can be stored for decades as well, yet replacing batteries every 3 years to run a compressor fridge may not be possible.  It would be nice to have both options.  Of course the 3 way fridges can also be run off on inverter, or directly off 12vdc, however they are not designed to run primarily on electricity, and are not as efficient overall on electricity, or become as cold as when run on electricity as the newer compressor types, yet it can be done. They require about 8 to 11 amps 12 VDC, and would need 4 to 6 Trojan T-105 deep cycle batteries, or other deep cycle batteries rated at 200Ah or more, and 2 to 3 times the number PV panels providing 400 to 600 watts. Not good. The better compressor types sip power, using typically less than 4 amps at 12VDC, when the cycle.

If your budget for off-grid refrigerator limits your choice, then propane also happens to be the least expensive, according to the math.  And the propane refrigerator has no moving parts to fail.  The compressor types have not been tested to the same extent or nearly 100 years as are the propane type, and the more moving parts there are, then the more likely it is to fail.  Of course the older the propane refrigerator, the shorter is it’s remaining service life, especially if it is very old when purchased used.  They may last as long as 40 to 50 years.  Often they are 20 years old, or older when purchased.  And the colder the fridge, or the better is runs now, is an indication of how much time it may yet run into the future.

My unprofessional guesstimate is that an old propane fridge that can produce the temperatures that it was originally designed to achieve, will last many more years. The process of losing the hydrogen gas is usually a very slow process, akin to a very slow leaking tire that take years to deflate. If it currently operates as designed, this process as yet to begin.

Lastly, I should mention that I believe that owning two or more small units is better than buying one larger one.




39 Comments

  1. Very interesting Tunnel Rabbit. A mash up of historical cooling and modern follows. For those blessed with spring fed water a well insulated springhouse can both protect the spring from surface contamination like Deer poop (a great source of Giardia etc.) provide a nice reservoir of drinking water ready for basic filtering AND a nice refrigeration system used for decades by my Grandmothers small dairy operations. Some folks used to lower baskets of food-milk into their dug wells for the same effect.

    Both require forethought-effort and awareness of safety for the water supply. Don’t want to dump a bucket of milk into your water system as the time for water flow dilution and clean up is an annoyance.

    So in the more modern mash up using solar power to pump water doesn’t need batteries per say IF you set it up so the stored water is effectively the storage batteries. Either an elevated storage of daily use water or a hand pump comes to mind.

    The structure needed to support water at 8 pounds a gallon is robust OR you build the storage uphill from your use point. Folks who have experimented with rainwater collection have often “Discovered” the power of a barrel of water falling out of system when they failed to engineer the supports properly.

    We *Might* have to get used to the idea of less water pressure and always ready hot showers if things get *sporty* or more 3rd world. Think high tech deer camp instead of modern grid-propane truck supported life as we currently enjoy. If riots cause the cities to burn aka Rodney King style propane deliveries and grid power might be unavailable or unreliable for a great number of years?

    Now for the Refrigeration part. Since your going through all that effort to pump that water for toilet flushing-bathing-cooking-drinking-gardening and so on WHY NOT Use the natural Coolness of ground water by running it through several pipes (acting like a cooling grid) into an very well insulated chest style fridge? Then THERMAL MASS in the form of bricks-concrete or steel or can hold that coldness during the nights?

    We had such a set up in our deer camp but we developed a spring to run through the chest cooler as to keep our deer cool until we wanted to process them. Also kept our groceries nice and cool. I’ve friends that use the solar pumped version.

    As an planning aside I was told the reason that HVAC cooling units were rated in Tons was because of the Tons of stored ice they cooled like. Your thermal mass of the water cooler needs to be measured in tons. Spring houses use the tons of earth they are dug into. We used concrete to make the structure of our chest and insulated that so when cooled by the earth and water flowing would act as the thermal mass.

    1. Yes, we should all have a spring! I will also use a heavily insulated and in ground ice box to hold ice into late spring if I need that capacity. Salt preserves meat as well.
      Having a freezer full of meat is just not a practical unless it is used only on temporary basis while it is being canned up.

  2. I had an old Servel propane fridge that was older than me. It mostly worked ok except now and then it needed to be turned upside down which seemed to fix it’s problem. Getting it serviced was tough as the propane appliance techs weren’t too sure how to fix it and the old guy who knew these well had had a stroke and was no longer able to assist; they sure wished they’d paid more attention to what he was doing when he was still going strong! I finally replaced it with a 12V fridge that failed not long after the warranty expired(lived off-grid). I doubt they make them as good as the old ones anymore though; you could expect those to run for many decades. A side benefit of the Servel was that I had a drying rack with fiberglass mesh screened shelves hanging above it and the heat from the fridge vent was an awesome food dehydrator, using only the exhaust heat produced. Made the best dried blueberries!

  3. When looking for propane refrigerators do not overlook a running old Servel brand. They stopped making the heavy units in the mid fifties but many need only a good cleaning of the burner to make them functional again. I have had these for many years and the oldest working model was from 1928. The age can be roughly determined by the size of the freezer section. From an ice tray and 2 lbs. of meat to the largest double door with it’s separate freezer compartment. An apartment size unit runs on about 7 gallons per month. They are quite capable of being used as freezers when turned down to their lowest settings. There are still a few people around that can adjust them for different altitudes.

    1. Hi Joe,
      Glad to get your info on the per month consumption rate of an apartment sized Servel. This dispels some the opinion that the old fridges were not as nearly as efficient as the modern designs. One of my fridges is a Dometic Model 211 from the late 1970’s, runs great.

  4. This column answered several questions I have had about this type of refrigeration. I found the cost analysis to be helpful and your decision to buy two smaller units a level headed approach to efficient living. The majority of home appliances are engineered to last about 10 years which makes propane something to seriously consider.

  5. “One option is contacting large recreational vehicle (RV) and fifth wheel trailer dealerships. They often have used RV refrigerators available with cosmetic issues (typically just scratched or dented doors) that make them very affordable.” JWR adds to the great Tunnel Rabbit article.

    The need for refrigeration for a diabetic person is a ‘life or death’ need. Insulin has to be refrigerated. There are other medicines requiring refrigeration too. … There will be future local disasters where people lose electrical power for weeks.

    A gasoline powered generator is an option for emergency power. But, they make a lot of >noise. [It’s more difficult to store gasoline than propane. +Where I live, it’s illegal to ~just stash a large quantity of gasoline at your house.]
    *********************************

    Reading about survival after a hurricane, the >noise made by a generator didn’t lead to ‘peace’ in the neighborhood. … Neighbors wanted replace the generator-owners freezer items with their >own items. … Foresight by some people led to dangerous situations and arguments with neighbors.
    [Are all neighbors reasonable and polite?]

    The systems discussed in Tunnel Rabbits article fit into the ‘grey man’ approach recommended by SurvivalBlog.

  6. I didn’t notice any mention of a third option. Kerosene refrigerators. I my area the Amish use kerosene. I have no first hand experience but think filling a tank up with kerosene and trimming the wick shouldn’t be to much . Plus maybe other oils ,( like french fry oil ) or bio diesel could be used ?

    1. I did not know about the kerosene option as it is probably not widely available or popular. I might prefer it, because it is not a compressed gas and substitutes might be used. The low cost of propane hard to beat tho. I’ll be looking into it tho… Thanks!

  7. As long as you are convinced that the interrruption in industrial society will be brief, propane is a good option. For longer term, I prefer solar-powered electric fridge and/or freezer, which can run by day and slowly warm by night. Freezer is a better bet for this system, since you can set it cold enough that it still will not thaw overnight, but a refrigerator has a narrow window of acceptable temperatures. Lots of twenty and thirty year old electric powered mechanical refrigerators and freezers are still running, but of course there is no way to know how long one built today will last. My Outback inverter has been running continuously for ten years now…I do not think there is enough experience to predict its life expectancy. Life of solar panels should be long…20 years +…barring accidents.

    Another refrigeration option is thermoelectrics. No moving parts, nothing to leak, no inverter required as they run on low-voltage DC power. You can buy picnic-cooler-sized units…or build one.

    But none of these things can be repaired or built without deep tech infrastructure.

    Canning may seem a more robust option for long-term disruption, but only if you have rubber trees (and sulphur and processing equipment) to make new jar seals.

    Pickling and salting are good for preservation times of a few months in cool climate…salt you will need anyway, so find that local source NOW.

    Drying is the only long-term food storage option I know of that has no reliance on technological infrastructure.

    Just pick how long you want yourself and your kids to be able to survive, and you know what to prep.

    1. That’s just it, modern methods are not sustainable. I’ve looked at the options out there and decided that propane was my best bet. I’ve lived without refrigeration for years, so I know how to make do with out. The 2.0 cu .ft. or 3.5 cu.ft sizes I have can be run the longest. Hated to let the big one go, but the profit from the sale could buy enough propane to run a small one at today’s prices for 13 years if I had enough tanks to hold the gas… And if propane is available in the future, the price will likely be higher. Of course a family would need something larger.

  8. Thank you Tunnel Rabbit for the informative article. I’ve been debating about additional refrigeration/freezing capacity. Where I live, middle of nowheresville Idaho, we have an abundance of meat. Many ranchers are selling direct, so while the meat processors (small shops that mainly do deer, elk, and bear) are incredibly busy right now, we have an abundance. That will not change any time soon since out here “Black cow lives matter”. It occurred to me that having butchering skills is a great skill to have. Our family decided to do a trade – one family bought half a pig and one family bought half a cow so we’ll mix and match depending upon what we might need or want, and we borrow freezer space from one another.

  9. Just a note about the size of the refrigerators. Most people have refrigerators of at least 21 cubic foot capacity. Some people have 24 foot and even 30 foot capacity refrigerators. I replaced my old 21 cu ft unit with an 18 foot unit and was not satisfied because it was just too small. A 10.5 unit or two smaller units may be suitable for camping or emergency use, but you may find them too small for your family.
    Don’t get me wrong, I heat and cook with propane and like using it vs wood stoves etc., but I would need a propane refrigerator of at least 21 cu ft capacity.

    1. I suppose the article is as much about propane refrigerators as it is about examining our ability to sustain a useful technology during a long term socio-economic crisis lasting perhaps 10 years or longer. I looked at my needs vs. wants, vs. affordability.
      At my extreme low income level, not unusual for many persons in my age group, this was my choice.

      1. We have a good sized fridge and an upright freezer now, but if there was no grocery shopping we would not need them. Dairy, fresh meat and leftovers would be the primary need so dorm size would work post TEOTWAWKI.

        Also, ammonia is used at many commercial chilling installations, but it’s a poisonous gas. I’m not sure I’d want it in my house. Hydrogen would be the better option in my book.

        1. I’ve never heard of anyone being poisoned by the ammonia in a home refrigerator. That must be a rare occurence. And the only times I’ve heard of them leaking is either when they are being moved, (damage to the coils) or when they are being repaired or serviced.

          1. You are probably correct, sir; I may have over reacted as a result of attending too many safety meetings back when I was in the chemical industry. Luckily, it smells strongly, so if you smell it, you can get some distance and you’ll be OK.

  10. Another option I have seen videos of is to buy one of the smaller chest freezers (5 or 7.5 Cu/ft. and use it as a refrigerator and power it with a solar panel. I don’t have a link to one of these videos but probably a search of youtube will find it. These newer chest freezers are so efficient that in one of the videos they were using it as a freezer, powered by one PV panel and only actually ran it for a few hours each day. But the original video simply set the thermostat to the warmest setting and used it as a regular refrigerator not a freezer

    1. Hello OneGuy,

      That is definitely an option I could have look further into. The big attraction to the propane fridge is it’s time tested reliability, serviceability, availability, and it’s lower price when purchased used. It is rare to see one of these modern compressor 12vdc refrigerators for sale used. And I do not have any information about the long term reliability of the high quality Engel, or other similar brand compressor refrigerators, when used daily over a period of ten years. It would be good to look deeper into this option you bring to our attention.

      Granted, propane refrigerators can fail, however I believe I could repair or replace any part, including a critical part, the thermocouple, with ease. In the event that I could not locate a replacement thermocouple, both of mine can also run on 12vdc, or 120VAC but the require at least twice the electric power to operate as does the compressor type. The average cost of each of my small 2 and 3.5 cu. ft. propane fridges was $100.00 ea. That is hard to beat. The classic Dometic 211 is about 40 years old,still works good. The other is from the 1990’s is an off brand. Both have time on them, yet few miles, and at least one of them will outlast me. Here is a video of a Serville from 1955 still in use.

      Serville Gas Fridge
      https://youtu.be/O7u629LcevI

      Here is a video of what was required to service and repair an old Consul 10.5 cu. ft. propane refrigerator. Note how cold this fridge can get, -20F.

      https://www.youtube.com/watch?v=UOAe7Rd7Y6A

  11. Good stuff!
    Also c/o Sundanzer chest units. 12/24v and comes with two thermostats. Fridge or freezer.
    We have the 8cu ft model and use about half the space to freeze 4, 2gal buckets that we swap out every other day in a dead 16cu ft chest freezer.
    Ice box stays below 40 most days.
    Yes. Another chore and less freezer space but it works for us.
    Panels are about 1000 watts into the batteries at 24v and the system also runs lights and fans in that room and the bathroom.
    4″ insulation in their units and plan to add to that as stated in article.
    Thanks. Chris.

    1. Hi blaine,
      Glad you it worked for you. Life is short and the retirement check will soon loose it’s purchasing power at a rapid pace. As we have found the time to adapt to the future, we’ll be better off.

  12. This might be two personal so if I get no answers that is ok.
    Anyway what is frugal in actual income. Just an example both my brother and sister live on social security plus small annuity. One pays zero Federal and State tax. What’s unique they are 3 years apart in age but yearly income is about the same at $32,000.

    1. Hi Skip,

      The term ‘frugal’ means different things to different people. It is relative. Because of my bad feet that prevents me from walking and standing for more than a few hours without severe pain, my income is limited. I do not receive any help from any government, and do not want it. I expect my income this year to be less than $3,000.00. During ‘normal times’, for a limited time, I can get by on zero income. Once a hyper inflation occurs, my few expenditures can be cut by 100% for several years if necessary. If I can do it, anyone can do it. When the day comes when no man can work, or when price inflation runs rampant, I will not feel the impact as others will. I have learned to barter, and bargain hunt to make this happen. It is an art and skill that in improves with practice.

  13. Tunnel Rabbit!
    Thank you for such a great article — interesting and informative! In fact, we had been talking about back-up refrigeration options very recently. Your article has added a lot to that conversation and the development of ideas and options!

  14. I’ve used propane refrigerators in campers for 50 years. They work, never investigated propane consumption. The small frig in my pop up must have a bad sensor because it typically freezes the refrigerator compartment. It does require 12VDC for control power (propane valve and igniter)

    The propane refrigerators have to be less efficient than electric refrigerators due to the coolants and heat transfer process. You can feel the heat coming off the refrigerator burner exhaust in my camper, and waste heat is wasted energy. I’ll have to check out the math when I have time.

    Sun Frost and others make off grid electric freezer/refrigerators that they advertise as being more energy efficient than propane. Buy some panels and it might be possible to run the system without batteries, cooling the refrigerator during day and letting it warm up overnight, but your power must be reliable, so good sun, batteries or backup generator. Put it in a basement to minimize warm up. Last time I looked at the off grid electric refrigerators they were expensive and small complicating the economics. They do make 12-48 VDC freezers so inverters aren’t required.

    I like the simplicity of propane refrigeration. I think this is the main advantage. They also will do well in areas that have frequent rain and solar isn’t a steady option. I’m a big fan of off grid solar because of its long-term availability, long life of components and renewable energy source. Generators are too noisy in a grid down situation, but propane doesn’t have the noise problem in a frig or cooking situation. I haven’t looked seriously at the propane refrigerators yet.

    Insulation matters. I have a 50+ qt whynter frig/freezer, DC, and it consumes quite a bit of electricity. I keep a blanket over the lid because I can feel the cold, but I vacation with ice cream. I run it on long vacations off of a 180 AHr Battery bank in the van and the batteries need charging every night. The insulation is why the off grid frig/freezers use so little energy. I suspect the 110V chest freezers could be better insulated but MFGs don’t have the incentive. I also believe many put the condensing coils in the outside walls so adding insulation is problematic. I need to use my IR temperature gun and figure out where the coils are in my chest freezer.

    I like the propane because you can bury big tanks and store it indefinitely, but it’s not renewable like solar. I have propane generators to utilize stored propane.

    My short term plan is to use solar panels and a normal freezer. A normal freezer built today uses very little electricity. Once past the initial failures they tend to have bathtub failure curves. A 21 cu ft chest freezer can use 1060 Whr per day, maybe 400 W of panel for year round operation. I would have 3-4 years before batteries go dead, longer with more expensive batteries, but chest freezers can survive 24 hour power outages without a problem, so sitting overnight shouldn’t be a problem either.

  15. For those of us living in the northern regions, here’s an example of a “refrigerator” built into the wall of a house. https://youtu.be/w68z-YJvei4

    The same fellow shows how salted water freezes colder than plain water.
    https://youtu.be/PRxpWArwavk

    This man has lived off the grid for many years, and has lots of innovative ideas on how to reduce expenses and live comfortably with less. Plus, he has a great sense of humor. His videos are quite entertaining. His YouTube channel name is
    OFF GRID HOMESTEADING With The Boss Of The Swamp

  16. Tunnel Rabbit, salt water freezes at 28 degrees, fresh at 32 degrees. The salt also provides an internal matrix for the ice crystals to stay stable for a longer period of time instead of doing a phase shift from ice to cold water. You said you live in Montana, I live in Grangeville, Idaho and enjoy your commentary. I have had RV’s for years and use to use a small RV refer in my shop when I lived in Alabama and I used a 240 gallon tank and it would last me four years of running a 3.5 cu ft and a propane burner to heat up my coffee from a camping percolator. I did add extra insulation to the refrigerator.

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