paul has a new video  

 



visit the thread.

see the DVDs.

  • Post Reply Bookmark Topic Watch Topic
  • New Topic

off grid appliances  RSS feed

 
H Warner
Posts: 10
Location: northern New Mexico
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I'm living off grid now in an RV with a propane stove/fridge. I'm planning on building the "main cabin" shortly and am wanting to know about off grid appliances, especially fridges. I want an electric one because i dont want to be dependant on propane for that; it's bad enough for our stove. What is a good brand? I found Danby online and saw Lowes sells them, are they good? The price is right so I'm wondering if purchase price is reflecting quality or energy consumption (the website doesnt say how much energy they use).
 
Ken Peavey
steward
Posts: 2524
Location: FL
89
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I have a Magic Chef which operates on 1.4 amps for cooling, 1.76 amps for the defrost cycle. I think its 10 cuft. Plenty of space for me.
Sunfrost is a brand that produces highly efficient appliances. I don't know much about them but I believe they offer DC models.
 
Cj Sloane
pollinator
Posts: 3737
Location: Vermont, off grid for 24 years!
87
bee books chicken dog duck fungi solar trees
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I've owned a Sunfrost 12v for about 18 years. It's OK but not great. The fridge doesn't ever get as cold as I'd like and though the freezer does stay below 0 it's not cold enough to keep ice cream in good shape.

If I had to replace it I'd consider just getting a chest freezer and keep fridge items in a cooler with ice made in the freezer or in an ice maker. I have used a chest freezer as a fridge with a thermostat/plug item you can get from a place like Northern Brewer. It works and saves energy but is super inconvenient for a family of four with kids.

If you go for the Danby make sure it's the exact model you want. I've poured over those Energy Star charts and while some Danby models look really efficient I don't think those are the cheap one you could get at HD.
 
Cj Sloane
pollinator
Posts: 3737
Location: Vermont, off grid for 24 years!
87
bee books chicken dog duck fungi solar trees
  • Likes 2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Ken Peavey wrote:I have a Magic Chef which operates on 1.4 amps for cooling, 1.76 amps for the defrost cycle.


You most definitely do not want a fridge with a defrost cycle if you're off grid.
 
Dave Hartman
Posts: 51
Location: Off grid in the central Rockies of Montana (at 6300') zone 3-4ish
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I have read about using a small chest freezer with a external thermostat control added and it only consumes around 100 watts per day. Heres two articles http://www.treehugger.com/kitchen-design/man-retrofits-freezer-to-make-an-ultra-efficient-fridge.html and http://www.thedailygreen.com/green-homes/blogs/diy-hacks/7255 I will be doing this soon as I am off-grid and wanting to reduce my propane addiction.
 
Cj Sloane
pollinator
Posts: 3737
Location: Vermont, off grid for 24 years!
87
bee books chicken dog duck fungi solar trees
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I tried this and like I said, it's really inconvenient for short term food storage. You'd be better off making ice and using the ice to keep a cooler cool.
 
Vern Faulkner
Posts: 35
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I'd suggest looking at either the Steca or Sundanzer brands. Both are about the same, energy consumption and price-wise. Their draw is quite reasonable (70 watts/day for fridge, IIRC).
 
Devon Olsen
Posts: 1068
Location: SE Wyoming -zone 4
7
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
i was looking at a site the other day - cant remember which one - that was offering solar freezers that ran entirely off of their small solar panel, no battery or anything, it was a chest fridge that got a little part of the bottom that froze so that you could store frozen goods in the bottom and non frozen, sensitives in some racks on the top

for off grid a chest style definately seems better to me, and thank you for sharing dave, nice link

 
H Warner
Posts: 10
Location: northern New Mexico
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thanks, guys! I've done some research and am looking at doing some more before I buy. I really like the idea of the solar freezer with their solar panel, will have to search for that! I know the chest type is more effiecient but I'm used to the uprights. Will look at both and see what pans out! I'd rather pay more for a better unit and less solar power than less for one now and have to buy another two panels!!
 
Mabel Green
Posts: 6
Location: Australia
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I saw on websites that the Sundanzer sell chest-style fridges, which would be my personal first choice. I can't get them 'across the pond' though - almost tempted to pack up and move! We did the chest fridge conversion thing here for 3 years. Loved it. It does have downsides though. It needs cleaning about once a week to remove the moisture build-up. It takes time to get use to. No plates in the fridge.. you have to put left-overs in containers. Other than that, it used very little power (.2kwh per day) and it was so quiet. The reason we had to get a 'normal' fridge after 3 years was the tubes that hold the refrigerant are designed to be frozen in a normal chest freezer.. so they eventually rusted and leaked. It was a sad goodbye.

If the chest freezer is designed to be run as a fridge, it wouldn't rust and leak out the refrigerant, and I'd be singing it's praises once again. If only I could find such a thing here. I'm keen on not spending the extra $$ on more panels and batteries just to run a 240v upright fridge that lets all the cool fall out every time I open the door to see what's in there to snack on. Ugh!
 
Cj Sloane
pollinator
Posts: 3737
Location: Vermont, off grid for 24 years!
87
bee books chicken dog duck fungi solar trees
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Mabel Green wrote:... the tubes that hold the refrigerant are designed to be frozen in a normal chest freezer.. so they eventually rusted and leaked.


I never heard that before. I'll have to ask my husband about that (he's a master plumber & just took a class on refrigerant).

I have a small chest freezer that I'm only running during summer months because I'm off grid. The rest of the year it being used to store food in my mud room. The mice can't get in and the temp doesn't really get below freezing or above 45F.

I hate to say this but those chest freezers are so inexpensive it may be cheaper to keep replacing them than to go with a standard fridge.
 
Jeff Steigerwald
Posts: 12
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I live off the grid with a 4.3 KWH PV system and 8 Rolls Surrette 6v/400ah LA batteries. I have a full size Kenmore side by side fridge that I brought with me from my previous home in the suburbs. To make it more efficient I turned both the fridge and freezer down to the lowest setting-this is the warmest setting if you want to look at it that way. I turned off the ice maker and went back to using trays that I empty into the ice dispenser on the freezer door (a nice lux item!). I have (2) 1 gallon water cubes that I rotate (daily) frozen between the freezer and fridge. These take up the top shelves of both sides, but the extra coolness from the frozen cubes keeps running minimal. The fridge, lcd tv, and led lights are all I run on electric for the most part. When the sun is out - I will run the washer during the late morning/early afternoon - I line dry, so no dryer appliance needed. My heat comes from a Sedore 3000, hot water from a SunBank solar hot water heater, and I cook on a Brown non-electric LP stove (100lb LP tank). I never have an issue with low batteries, even on multi day rain events.
 
Cj Sloane
pollinator
Posts: 3737
Location: Vermont, off grid for 24 years!
87
bee books chicken dog duck fungi solar trees
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Mabel Green wrote:The reason we had to get a 'normal' fridge after 3 years was the tubes that hold the refrigerant are designed to be frozen in a normal chest freezer.. so they eventually rusted and leaked.


Well, my husband said there may be an issue but not the one you suggest. All the tubes he has seen are stainless steel or copper, neither of which rust. Also, he said the refrigerant doesn't freeze but does the opposite, it boils. It changes from liquid to vapor at the compressor.
 
H Warner
Posts: 10
Location: northern New Mexico
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
@Jeff, Wow, I wish I had that much power! We're just starting out and we have about 400w of solar right now, with 6 golf cart batteries. We poor folk here and cant upgrade for a few years yet, which is why I need a better fridge with no more panels! good thing is that we live in the desert sw and we have lots of sun... Once the cost of panels goes down, hopefully, we'll be able to afford a nice upgrade.
 
Mabel Green
Posts: 6
Location: Australia
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Cj Verde wrote:Well, my husband said there may be an issue but not the one you suggest. All the tubes he has seen are stainless steel or copper, neither of which rust. Also, he said the refrigerant doesn't freeze but does the opposite, it boils. It changes from liquid to vapor at the compressor.


That might actually be really good news. I'm looking at a 12v chest freezer at the moment (on eBay, urgh!) that says it can be used in refrigerator temps as well. If what you say is true, then it might just be the answer I was looking for! I noticed most tubes I saw online were steel coated with copper. They're listed for use as either fridge or freezer tubes, so perhaps the freezer I had before was just terrible quality? It'd be just my luck that the "quality" "Made in Australia" freezer we chose was worse than the "cheap" "Made in China" freezer we're looking at now.

I admit, the 240v chest freezer we converted was around the $600 mark.. the 12v one is around the $900 mark. Ouch hey! It hurt my green heart to throw a shiny scratch-free freezer away last year though, so I don't think I could do it again.

Our family doesn't have any other 12v appliances other than the laptop car charger, mobile phone chargers.. that kind of thing. Thinking of using 12v LED lights.. anything to avoid the cheap inverter and it's losses.
 
Cj Sloane
pollinator
Posts: 3737
Location: Vermont, off grid for 24 years!
87
bee books chicken dog duck fungi solar trees
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
What brand is the 12V freezer?

I have a 12V fridge and it doesn't get as cold as I'd like. Neither does the freezer portion. It freezes but not cold enough for ice cream, for example.
 
Mabel Green
Posts: 6
Location: Australia
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Cj Verde wrote:What brand is the 12V freezer?

I have a 12V fridge and it doesn't get as cold as I'd like. Neither does the freezer portion. It freezes but not cold enough for ice cream, for example.


It's called a Beier, which is made by the same people who make Heier and other cheaper branded freezers/fridges. I'm asking all the questions about the tubes to the seller.. the seller is probably sick of me by now! haha. It only as a 12 month warranty, so when they say that running it as a fridge won't shorten the life of the freezer, all it has to do is last more than a year huh? From our previous experience, our last converted chest freezer lasted 3 years almost exactly. It was 240v though - I havn't used 12v fridges or freezers yet. (Caught between two worlds at the moment, hanging out for the off-grid one!)
 
Bill Bianchi
Posts: 227
2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I realize this suggestion isn't electric, but what about converting your propane refrigerator to operate on methane and building a methane digester to feed it? That would get you off propane without increasing your electric usage.
The downside is you would have to feed the digester each day to ensure ongoing methane production. The upside is that it wouldn't take more than a few minutes of "work" per day to get refrigeration 24/7 and the fuel is renewable, homemade, and inexpensive.

It's just a different possible option, if you like.
 
H Warner
Posts: 10
Location: northern New Mexico
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
hey Bill, I dont know if methane would work here in the winter because it gets so cold. I would understand that methane has to "cook" like composting. With it being as cold as -30 in winter, that's way too cold to "cook" anything, cheaply. It is something to consider, however, and before I discount it, I will look into it further. Thanks for the idea!
 
Cj Sloane
pollinator
Posts: 3737
Location: Vermont, off grid for 24 years!
87
bee books chicken dog duck fungi solar trees
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
On the plus side, at -30 you don't need a fridge!

But... I stored some for outside in an old non-working fridge and when it got too cold I couldn't open the door. The fridge in the mud room doesn't get stuck like that though so there are work arounds.
 
Bill Bianchi
Posts: 227
2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hello, H Warner.
-30 makes me shiver just thinking about it.

I suppose you could store methane in innertubes during the warmer months, then feed the fridge from them in the winter. Could stack the tubes on a post and put weight atop the stack for pressure. But, all that starts getting more complicated and while possible, it's probably more work than necessary to accomplish what you're after.

For those in warmer climates, perhaps methane or producer gas (stored from a gasifier) might work out better. Thing is, the burner would have to be adjusted for either methane or producer gas before the propane fridge will work. I don't know what is involved with that.

I wish you luck with whatever method you decide to use. Keep us posted, please.
 
Mark Boone
Posts: 10
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Among Ohio's techno-Amish (who are pretty flexible about technology as long as it is 'off grid') Lehman's General Store is a favorite. No url since I don't intend this as spam, you can google it. They have a lot of gas and DC appliances - including dual or triple use ones that can switch between them. Good place to find products you can try to source locally or directly from manufacturers.
 
Cj Sloane
pollinator
Posts: 3737
Location: Vermont, off grid for 24 years!
87
bee books chicken dog duck fungi solar trees
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Lehmans

It's not spam if it's a legit reference.

I do not recommend this hand powered pump as we could never get it to work. Not sure what the problem was but my husband is a master plumber so I don't think it was an issue on his end.
 
H Warner
Posts: 10
Location: northern New Mexico
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thanks for all the helpful information, guys! I'm looking at getting the small 5 cu ft Sundanzer freezer and using 2 ice chests I now have for the "fridge" portion. I like the idea of freezing gallon jugs to keep the coolers cold. Plus, it sounds like the Sundanzer is one of the best brands I can get. they offer a 12v model as well, so that will be very helpful in saving solar juice. I have also posted a question about water pressure tanks! Since I'm new to off grid life, this is a great way to have questions answered with all sorts of helpful comments from great like minded folks!
 
Su Ba
pollinator
Posts: 993
Location: Big Island, Hawaii (2300' elevation, 60" avg. annual rainfall, temp range 55-80 degrees F)
125
books forest garden rabbit solar tiny house woodworking
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
We started out using a propane frig but eventually upgraded to a chest refrig and chest freezer. They are both Stecas. Frankly, I love them. They are very low energy users. You do need to maintain them, though. Not for the lazy. Once a month I clean out the frig. By placing an old towel on the bottom, any condensation is sucked up by the towel. Without that, you would find moisture collecting on the bottom of any chest frig. The freezer of course is not frost free. So occasionally it needs to be defrosted.

All in all, I am quite satisfied with them.

...Su Ba
kaufarmer.blogspot.com
 
Martin Bishop
Posts: 20
4
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Please let me know how this worked out. I too have been looking at the 318L Beier. I have a 200L 240V Chest Freezer with External Power Cut off Thermostat, Freezer cost $50 Gumtree, thermostat $30 Ebay

$900 Is a lot more than $80, but I am considering all options.

I made a spreadsheet, and would love feedback from anyone. Math may be off here and there, but at least you get the idea.

the 318L Beier says 75W Fridge mode 90W freezer mode. @ 12V that is 6.2Amp an hour



According to my math I show the chest freezer using a fraction of that power, but it is hard to know for sure the best option since the inverter sucks a bit of power as well.
 
Martin Bishop
Posts: 20
4
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I just purchased an $8.00 Refrigerator Thermostat that I am going to stick in my 200L Chest Freezer as a test. I have a similar 5 Pin Thermostat in the freezer now, but it is a freezer version. From the looks of it I should be able to swap them out and get a bigger range of temps.

http://www.ebay.com.au/itm/331005495313?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Product Name Refrigerator Thermostat
Temperature Range -15 ~ 21°C
Voltage Rating AC 250V 3A
Rated Frequency 50/60Hz
Size 6 x 3 x 2.7cm / 2.36"x 1.18"x 1.06" (L*W*T)
Cord Length(Approx.) 60cm / 22"
Material Metal
Color Copper Tone
Net Weight 68g
Package 1 x Refrigerator Thermostat
 
Adam Klaus
author
gardener
Posts: 946
Location: 6200' westen slope of colorado, zone 6
65
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
thought I would just drop a plug for the Sundanzer chest fridge and freezer units. I have owned one of each, run off my solar system, and housed in an open barn, for the past 6 years. No issues whatsoever. Really excellent workhorse units that I would reccomend to anyone. In the deep winter, I turn them off, and the uninsulated barn is cold to where they stay cold inside just fine. They run either 12 or 24 volt, no conversion, and are connected directly to my batteries. If you need such a thing, I have zero complaints with my Sundanzers. good luck!
 
Ken Peavey
steward
Posts: 2524
Location: FL
89
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
That Magic Chef I spoke of crapped out.
It was replaced under warranty, then the replacement crapped out. I got my money back, shopped elsewhere, got a full size fridge.
Magic Chef has lost my interest. Made in China JUNK.
 
Cj Sloane
pollinator
Posts: 3737
Location: Vermont, off grid for 24 years!
87
bee books chicken dog duck fungi solar trees
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Were you using the Magic Chef off grid? With the defrost?
 
Len Ovens
pollinator
Posts: 1452
Location: Vancouver Island
29
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Martin Bishop wrote:Please let me know how this worked out. I too have been looking at the 318L Beier. I have a 200L 240V Chest Freezer with External Power Cut off Thermostat, Freezer cost $50 Gumtree, thermostat $30 Ebay

$900 Is a lot more than $80, but I am considering all options.

I made a spreadsheet, and would love feedback from anyone. Math may be off here and there, but at least you get the idea.

the 318L Beier says 75W Fridge mode 90W freezer mode. @ 12V that is 6.2Amp an hour

According to my math I show the chest freezer using a fraction of that power, but it is hard to know for sure the best option since the inverter sucks a bit of power as well.

Put the thermostat before the inverter. Use an inverter big enough for the freezer/fridge. It does become more of a challenge

If I was running a freezer off grid, I would want two thermostats:

1) sunlight thermostat for when the sun is out and I can run directly off the sun... no batteries. This would be set as low as I could go without the unit running all the time or out of it's good efficiency range.

2) battery thermostat for night time or cloudy days when the power is coming from batteries. This would be set to -10C (your ice cream might a bit soft but the food would be safe) Hopefully, the frozen food at -30C and the fact that I don't normally open the door at night would keep this thermostat from ever becoming active.

The problem with AC freezers is that they can not be over insulated. The little heat pump, pumps heat from the inside surface (so we can't insulate there) to the outside surface (no insulation there either). So, This is where we get into manual stuff. Maybe insulation could be added over night... I think this would be a problem, I don't want to set an alarm to get me out of bed to remove it if the unit needs to run However, an Icebox (instead of a fridge) could be super insulated. If not opened, the ice would last for a long time... the ice comes from the above freezer and is removed from the freezer towards the end of the days sunshine.

If you have a stream that starts on your property higher than the freezer, it would be possible to use some of that water to cool the outside of the freezer (not the compressor which will actually be less efficient if cooled too much). Insulation outside of that may help if the water is plentiful/cool enough. If it is cool enough, it may be able to keep food chilled so a fridge is not needed.

If we have the knowledge, we can take the AC freezer apart and put the radiating loop outside of the box allowing us to add lots of insulation. The amount of insulation is a compromise depending on how often (and for how long) the door is open.

To me the freezer is the one thing I could not do without in an off grid home that needs electric power. Lights and entertainment are "nice" and would probably be provided... but freezer first.
 
Simon Brown
Posts: 15
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Please forgive me if already mentioned..I believe you can make a firewood powered fridge..happy to chip in if someone wants to start a thread. After all..gas fridges are simply using heat..gas !!
 
Len Ovens
pollinator
Posts: 1452
Location: Vancouver Island
29
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Simon Brown wrote:Please forgive me if already mentioned..I believe you can make a firewood powered fridge..happy to chip in if someone wants to start a thread. After all..gas fridges are simply using heat..gas !!


Yes but... There are two things I would see as show stoppers with that idea.

1) I need to go somewhere for the weekend (a week or two would be worse), How do I keep the fire going just the right amount so the milk doesn't freeze and the meat doesn't thaw? A wood fire needs personal attention. Gas can be controlled by microvoltages without extra electric input and a thermostat can keep the unit at the right temperature with no human input aside from making sure there is fuel available.

2) keeping the fire from being too hot and/or gumming up the inside of the fridge with junk would be a problem.

I don't know what temperature things need to get to make a propane fridge work, would hot water get hot enough? heating water with wood or solar would allow it to be controlled. It would still require some power to pump around, but maybe less than a compressor... then again maybe not.
 
Simon Brown
Posts: 15
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I agree ! its not a solution for you..maybe i shouldnt have introduced the idea. I think it is technically possible to do it and control it..but would require a major amount of work and experimenting.
 
Len Ovens
pollinator
Posts: 1452
Location: Vancouver Island
29
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Simon Brown wrote:I agree ! its not a solution for you..maybe i shouldnt have introduced the idea. I think it is technically possible to do it and control it..but would require a major amount of work and experimenting.


Ideas have to start somewhere. Certainly the idea to use heat (from whatever source) makes sense. Assuming that anyone would want to be able to walk away from their refrigerating unit for any length of time I think is a must. So a wood fired heater would have to, like some pellet stoves, be able to stop and start. A viable solution for starting something in the morning and having some controller that directed flame heat towards the chiller and away as needed could work. There are fire setups where one wood load can last for 8 or more hours and still burn clean. That is probably not enough. Basically, we have something that requires energy storage. We have been talking about heat, but absence of heat may be the better route.

I am reminded of a man on Long Island (I think) who had used antifreeze in a thermo-syphon to freeze a very large ice block during the winter where the ice block lasted him through the summer till the next winter. That would not work for me here (I am still working outside in short sleeved shirts), but using a solar or wood fired chiller could. Rather than trying to control temperature on a micro-scale by controlling the temperature of the air inside, cool a large mass. In this case the mass would be water. The temperature of the mass would be quite stable and varying the amount of insulation between the mass and the cooler cabinet would set the cooler temperature. So a manually operated chiller could work even for a cooler that might be left for weeks at a time. This unit would of course be much larger than a normal fridge... but so are storage batteries space eaters.

Could this also work for a freezer? Normally, water freezes at 0C and that would not be cool enough for safe freezing, we need at least -10C, but preferably lower. As happens, salt water freezes lower. If we add enough salt we can get the freezing point down to -21.1C or with other kinds of antifreeze even lower. The trick would be choosing something that is not too corrosive for whatever container/plumping we use and getting the mixture so that the freezing point is just a bit lower than the highest target temperature. We want this because the freezing point is the most stable temperature, the water will sit at this temperature from the time the water reaches it till all the ice has melted or changed phase.

Great! Next thing is to look at this system and think can we combine freezing and refrigeration? Many AC fridges chill the freezer box and control the air flow to the cooler to keep two temperatures running. So it seems doable. However, these machines are also controlled by the cooler temperature, not the freezer temperature. Cooler temperature is mostly controlled by how many times the door opens and the cool air gets out. So setting the air leak from the freezer to cooler for normal day to day use, may mean the cooler contents freeze if the user goes away for a few days and the door stays closed Marking the freezer to cooler air leak for "at home" and "away" may be good enough. But the problem at that point is an engineering problem of how much insulation and how much insulation gap are built into the unit.

Ok, there is the basic design. (as always CC by SA) All that needs to be done is get the right numbers for it to work. In the summer, solar heat could run a chiller and in the winter there are some places the outside temperature would be cold enough to keep things frozen. Hmm, that reminds me, the one thing I hadn't mentioned yet is that the room temperature matters. If folks goes away in the winter time the room temperature may drop upsetting things somewhat... this recommends a high mass home Also I am thinking there are valves (air flap for green houses, coolant in engines) that open on a temperature dependent basis with no outside power. A bi-metal strip may be strong enough for this.

In all, I think this is a viable solution and project. I was thinking to wait till I get some land, but this may be something that could even be done in an on grid house. I will have to think (a lot more) on some details and see if I have the resources to play with this where I am.

Thanks for the idea
 
Len Ovens
pollinator
Posts: 1452
Location: Vancouver Island
29
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Len Ovens wrote:
I am reminded of a man on Long Island (I think) who had used antifreeze in a thermo-syphon to freeze a very large ice block during the winter where the ice block lasted him through the summer till the next winter.


Nope, Four Mile Island. Here is the link.
 
Simon Brown
Posts: 15
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Dont have time to give such a thoughtful post justice...but shooting from the hip....

I love the idea of freezing a huge block of ice..all the shenanigans of a bonfire fueled freezer set up...just once in a while to freeze a new block of ice. Yes salt water etc.

Could use a bimetalic strip to automatically open/close access to ice. Loads and loads of insulation..or maybe underground where temperature is more stable.

Thermo electricity VICTORIAN style is way forward otherwise. Google Clamond Thermopile. Tech minded only. TEGS are useless imo.
 
Len Ovens
pollinator
Posts: 1452
Location: Vancouver Island
29
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Went looking into absorption refrigeration. Lots of stuff on the icyball... and why to not use it The icyball can be safe if used exactly right, but can also over pressure spraying toxic stuff all over. Ammonia has big use in the Crystal Meth world and so it is hard to get too... though you only need to get it once in a proper built system. Absorption chillers generally work in two temperature ranges... when used for air conditioning, the working fluid is water. The problem with water for what we want to do is that the cool temperature is not that cold... above freezing.

I watched A TED talk by Adam Grosser, where he talks about a fridge in a 5 gallon bucket with about a 3 gallon capacity. The chiller is heated over a fire for 30 minutes, let sit for an hour and stuck in the top of this bucket which it then keeps just above freezing for 24 hours. Cool! It does not use toxic working fluids, but he doesn't say what it does use Anyway, from what he does say, it appears that there are a number of things besides ammonia that will work without being toxic. (or corrosive... I guess they used sulphuric acid first) He also says that the tables that ammonia refrigeration is based on is incorrect.

What I have figured out is that absorption chilling has not been studied at least for freezing very much because it uses a lot more energy than using a compressor. The water based absorption chillers have been refined because there are lots of factories that are wasting heat and therefore the energy is effectively free. The standard that is used for RV/offgrid use was figured out long ago and just works so no one has done much with it because it is and always will be a niche market.

Using the parts of an RV fridge for a chiller... (where we started a few messages up) This is a refined icyball. Certainly safer. But how much of the reason it is safer comes from controlling the heat? That is would this become unsafe from overheating of the distiller and blow up if a bonfire was put under it (over exaggeration on purpose)? Or to put it another way, how closely controlled does the heat have to be to stay in the range where cooling is happening while not over pressuring the system? The idea is to evaporate the working fluid out of the water without boiling off the water... I think there is a range where the cooling end will try to get just as cold, but the speed of cooling will be determined by the amount of heat... just thinking "out loud".

Anyone have ideas?
 
Len Ovens
pollinator
Posts: 1452
Location: Vancouver Island
29
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I found another thread that already talks about using intermittent absorption cooling to do this. http://www.permies.com/t/30590/energy/Intermittent-Adsorption-Refrigerator

So I am asking questions there.
 
Dave Tedford
Posts: 8
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
We have been off grid for three years now. The first two years we used a small chest freezer on a timer as a fridge. It ran one hour in the day and one hour at night. Took a little while to figure out the sweet spot on the thermostat, but it worked well. We have a propane now, more expensive but convenient and easy to keep clean.
 
crispy bacon. crispy tiny ad:
Permaculture Playing Cards by Paul Wheaton and Alexander Ojeda
https://permies.com/wiki/57503/digital-market/digital-market/Permaculture-Playing-Cards-Paul-Wheaton
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!