Designing the perfect Icebox...?

[BPFox]

Years ago I had a Krown tent camper. It came with a built in ice box. It worked great. I used block ice made in a home freezer. The ice was on top but separate from the food compartment. The ice area had it's own drain and the food area was much deeper than than ice area. The cold air dropped to the bottom of the deeper food area and the food stayed cold and dry. It was just like taking food from a refrigerator only it used no power and lasted days. Never went camping and had to buy ice. Always had ice to throw out at the end of the trip. It had a lid just like a standard cooler. It was pretty well built. In fact, you could use it as a seat. Never thought much about building one, but if I did, I would copy that design.

[rbeemer]

You can also change the design of icebox to have 2 doors for the food compartment in a horizontal configuration, so that when you only have to open half of the fridge to get something out.

Just a thought

[DMcCam]

Hi Slowcowboy, sounds a lot like my Igloo. After experimenting, I found I had to have three blocks of ice (one on each end with one in the middle) and fill up over half of the usable space with bag ice too or my food will not stay cold enough. Even then I have to replace the bag ice every three days.

Greetings BPFox. The tent camper design sounds pretty cool, an insulated ice chest with two nested compartments. The top one has the block ice and the bottom is the food area. Do you remember whether it was galvanized steal or stainless? If I'm understanding how it worked, to get into the chest you had to lift out the ice compartment, correct? What were the approximate dimensions and how much did the ice weigh?

Hello rbeemer, Two doors could work for sure great idea! I would probably be easiest to have the two compartments separated in the front so the door seals would be simple. You would be able to remove the ice tray through the top door for cleaning. I like it, thank you!!

I've been talking with a metal shop teacher friend about the general construction. now I'm leaning toward a stand-alone icebox design. The whole thing would be constructed from galvanized steal with no wood. You could then frame out the space for it in the trailer, slip it in the space and secure it. Could build to suit too.

Thanks for the ideas. Please don't be shy, all ideas are welcome even the one's you think are common sense. Those are usually the best ones!!!

Dave

[Engineer Guy]

I'm running a very controlled experiment in my 120 quart Igloo '5 Day' Cooler to quantify what's already known intuitively, and acknowledged above: thermal transfer via water is more efficient than by air. With 2 frozen 2 Liter Bottles of Water inside and a Thermometer Outside Temp probe in a 3rd Bottle measuring internal liquid temp, 1" of water in the Cooler bottom results in exactly half the rate-of-rise over 12 hours in the monitored Water Bottle as air only. I finally got 5 days cooling out of my Igloo Cooler last year Boondocking at Lake Powell when I followed a Poster's advice [and my Grandpa's technique] and used a little water internally. Of course, the Cooler was in the shade on cool Dirt. In the 2010 Thread linked above, Hiker Chick used reflective Insulation for improved results, as I have prior.

Water is not 'bad' in conducting external heat into a Cooler more efficiently than air. It's more efficient. It's also more efficient at transferring Ice temp to Foodstuffs. If water conducts heat into a Cooler, the root solution is to super-insulate the Cooler; not avoid the more-efficient heat transfer medium. There's a Physics 101 reason Liquor Store Wine Chillers use water...

Accessories that hold many 12 oz. Cans vertically, and Baskets and Containers from a 'Dollar Store' could make Chest Cooler Food access much easier. All this has been solved before, and is partly why the hard core 'Expedition' Campers like Engels.

When this Thread is long gone, top lid Coolers will still retain cold air better, as did the Krown Tent Cooler. The old Coleman Cooler doesn't/can't rewrite Physics 101. Pictures from the Thread last year of the Coleman Wall depth, and the relatively-high volume of Ice used tell the tale. No assumptions need be made when simple Tests provide objective results. In contrast, only 2 frozen 2 Liter Bottles of Ice are keeping 1" of water cold and stable in my 4' long monster Igloo Cooler right now. Frozen Steaks in Air-free Zip Lock Freezer Bags and other frozen goods placed low and used as they thaw gradually is our time-tested technique.

Using 3" and 4" of Insulation nets these results, as mentioned at Backwoods Solar:

Super-efficient electric refrigerators and freezers designed with 3 to 5 inches of insulation use only one third the energy of most standard units.

The inverse of this is that amount 'x' of energy in a given block of Ice lasts proportionally longer at such Insulation levels. Some Food volume is sacrificed to Insulation, but Life's a series of tradeoffs. Carefully using space-efficient square Containers compensates.

Backwoods Solar

Food-consuming amounts of space must be dedicated to Ice because of losses through not-very-thick Walls of the creatively-named '5 Day Coolers' [including mine].

As with all Products, Sunfrost had to balance 'cold-losing' front door ease-of-use and Consumer expectation against energy savings. Breakthrough thinking like Sunfrost's, and that being tossed about here, occurs when old assumptions from Coleman, Sailors or the Peanut Gallery are tested rigorously and - in some cases - thrown out.

Sunfrost Refrigerator Specs

Were I to have to build one tomorrow, I'll build a super-Insulated version of the Krown Cooler. I'd envisioned any old Commercial Cooler of choice slipping down into a custom Thermax Box w/Lid. See one possible Container below that could be almost-filled and frozen with Water; Water and safe RV Antifreeze; or Salt Water.

This 2.5 Gallon Container could sit up horizontally to one side on L Brackets, just below the Lid, to effect the Krown Cooler idea. No drain req'd. Or, it could slide into vertical L Brackets in the Cooler center, and be held just up off the bottom. This would provide max cold surface area bilaterally while contacting water in the bottom to chill more efficiently. Cold pooled air would stratify in any case, and one can take advantage of that if ~1" of Water is objectionable. Note that Home Fridges de-stratify air with a Fan. The temp stratification 'problem' is noted in the Thread of last year.

Beta Videotape was technically superior - hands down - to VHS, especially when copying in Newsrooms after editing. Technically-inferior VHS prevailed in the Marketplace because it could record longer programs. Consumers voted with their Wallets for the technically-inferior medium. The same is true with Coolers, and using water in them, or in offering a 'cold losing' Front Door on Upright Home Freezers that reduces energy efficiency. Some folks figure a Cooler drain is to remove all water. I and my Grandpa use the drain to maintain a low water level. If you don't like water, the ~25x greater thermal transfer efficiency of it doesn't matter. We use square Tupperware-type Containers; put Chili in square Iced Tea-type pour Containers to minimize wasted Cooler space, and so on. Engel uses sliding Trays. For this Boondocker, tweaked Chest Coolers are an acceptable tradeoff.

Engel Coolers

We have a Commercial Cooler with a removable Container in the Lid we freeze. As the Krown Cooler establishes, Ice up 'high' is a great way to go. Super-insulation is what makes Space Station habitation possible where temps vary by hundreds of degrees, as well as making Antarctic Research Buildings habitable. Added to homebuilt Cooler design, significant performance advances like the Commercial Units linked above are affordable.
Isolate the inner Cooler environment via super-Insulation and then manage it by Food placement. Or not.

[eamarquardt]

I'm running a very controlled experiment in my 120 quart Igloo '5 Day' Cooler to quantify what's already known intuitively, and acknowledged above: thermal transfer via water is more efficient than by air. With 2 frozen 2 Liter Bottles of Water inside and a Thermometer Outside Temp probe in a 3rd Bottle measuring internal liquid temp, 1" of water in the Cooler bottom results in exactly half the rate-of-rise over 12 hours in the monitored Water Bottle as air only. I finally got 5 days cooling out of my Igloo Cooler last year Boondocking at Lake Powell when I followed a Poster's advice [and my Grandpa's technique] and used a little water internally. Of course, the Cooler was in the shade on cool Dirt. In the 2010 Thread linked above, Hiker Chick used reflective Insulation for improved results, as I have prior.

I'm not sure that you are testing what the issue is (at least in my mind). What icebox temperature for how long can be achieved when water is present in the bottom of the icebox versus no water in the bottom of the icebox. Ideally two identical iceboxes with equal amounts of ice, etc ought to be compared during the same time period under the exact same conditions. IE: a "controlled experiment".

Water is not 'bad' in conducting external heat into a Cooler more efficiently than air. It's more efficient. It's also more efficient at transferring Ice temp to Foodstuffs. If water conducts heat into a Cooler, the root solution is to super-insulate the Cooler; not avoid the more-efficient heat transfer medium. There's a Physics 101 reason Liquor Store Wine Chillers use water...

There is no doubt that if you want to keep something at exactly the same temperature and/or cool it quickly that keeping it in a water bath (with the attendant thermal mass and ability to conduct heat away faster) is the way to go. But, we really need to compare two identical coolers, one with standing water and one w/o standing water to evaluate the longevity of ice in each.

Super-efficient electric refrigerators and freezers designed with 3 to 5 inches of insulation use only one third the energy of most standard units.

You can't defy the laws of phyics! Rumor has it Congress tried to repeal them but failed.

Perhaps when they start selling the inexpensive foam coolers again during the summer, I'll buy two and do some testing. I have two Fluke dual channel digital thermeters and a "lifetime supply" of thermocouples (courtesy of my brother-in-law the "PhD rocket scientist" specializing in in heat transfer). Then we can end the speculation.

I also found and bought a Norcold (the same as an Engle) 60 quart ac/dc chest I found on Craigslist in Phoenix. Guy Mazzeo was kind enough to pick it up for me there and deliver it to the LA area!!!!!!!! Thanks Guy. I saved Suzy almost $600 by purchasing "preowned" versus new. She, however, isn't particularly thrilled about the money I saved her!!!! She will, however, get over it in time!! I also will buy a couple of data loggers (to measure temperature and cycle time) and do some testing over the summer to demonstrate that the cycle time of these units is proportionate to the abient/internal temperature difference.

Cheers,

Gus

[pete42]

I know nothing about heat transfer or how many btu's it takes to cool or heat. I do know on our old sailboat 30' Non'such the cooler was top loaded and had a drain worked well we could add block Ice for long trips 7 days or so cubed ice for the weekends food, beverages kept very well.

I have a coleman cooler somewhere in the garage like the one Len had we used it in pop-up many years ago I just hated buying ice or frozen milk jugs which took up most of the space so I bought a coleman 12/120 volt cooler which works for us we do add frozen stuff to help keep it cold.

I like the idea of a slide out chest style cooler mentioned.

In the past I have used a 120 volt dorm refridgerator plugged it in at home and when we reached campgrounds but not very usefull if boondocking.

pete

[Engineer Guy]

What was tested and examined singularly was Grandpa's, and a Forum Poster's, assertion that a bit of water - 1" chosen and measured out in this case - kept the item of interest - a 2 Liter Bottle of liquid in this case - cooler over time. If that 2 Liter Bottle was not 'enough' of a Food load in the Cooler, it was 'not enough' to an identical degree in both Tests. Variable between the 2 Tests eliminated.

1 'identical' Cooler - the single, dry-interior one at room temp I used - is as identical as you'll ever find vs. 2 Coolers. 2 Coolers could have differences - who's to say - but 1 Cooler can't. A Test pre-condition statement was to use 'what I had around'. That was a '5 Day' Cooler very similar to what the OP has and, like me, was 'underwhelmed' with the performance of. Identical Cooler used both Tests. Variable between the 2 Tests eliminated.

With Ice amount 'x', - whether ideal or not - the temp 3" down in the 2 Liter Bottle liquid of interest - monitored w/the same temp probe to x.x degrees - had exactly half the rate of temp rise with 1" of Water in the Cooler vs. only Air in the Cooler for an identical 12 hour Test period. The only reason to lengthen the Test time period would be if I could make more Ice overnight. The 0 F degree Freezer here in W. CO. is somewhat full, limiting Ice production size of mass. More Ice or more Food will merely lengthen the time over which the Cooler internal temp equalizes with the external temp, given a stable exterior temp during Test [which there was inside my House], and the fixed thickness/R Factor 'x' of the Cooler Walls. The variables of exterior Room temp and Cooler Wall thickness/R Factor were eliminated.

My hunch: when you're losing 'cool' hour-by-hour through fixed Cooler Wall thickness/R Factor 'x', the superior cooling transfer of Water vs. Air from Ice does matter, especially end-to-end in the Cooler. One proposed solution to the OP: consider placing the Ice in the center. The best of all Worlds might be a Krown-type Cooler with Ice up 'high', and a shallow Water 'bath' [or not] for Burger Meat, etc., in a 'well' below. A 2nd Book-sized Container that's frozen would help down in a 'well' for perishables to sit on, and wouldn't create the Water mess.

Thus, the sole variable tested w/little time invested: undrained Water & Air vs. only Air in the Cooler as the chilling medium. My conclusion: Grandpa was on to something. Folks can choose a more-effective Water 'bath' or not in their Cooler, or design and share their own Tests.

What 'should be' in theory re: non-moving Air cooling as well as Water in a Cooler is something I could not care less about. Theory doesn't reflect 'what is' re: Camping conditions. I'll be interested in your Summer Test results, but the OP isn't re-designing the purchased item you're testing.

But, we really need to compare two identical coolers, one with standing water and one w/o standing water to evaluate the longevity of ice in each.

I, and others, don't drink 'the longevity of ice'. We drink a bottled liquid. That is why I measured the temp in the bottle of potable Water each time the same internal distance down from the Bottle opening. It was pre-chilled to 34 F degrees overnight before each Test run to reflect how many of us prep for Camping.

Some other Posters dismiss, and rightly so, the idea of using a Cooler for Food perishables at all. No argument from me; we've 'lost' Food while Camping, too. Another Poster mentioned noticing inevitable stratification, as we all likely have. Good enough for me; he doesn't have to test for what he observes 1st person.

'Enough' Ice, or externally-supplied Cooling 'power', will replace cold Air lost to some degree when Drawers are opened. Drawers are all the rage now in high end Fridges and Wine Coolers under Kitchen Counters. With attention to Gasketing, etc., these inevitable losses could be minimized while enjoying the convenience of Drawers. As with the Beta vs. VHS bit of History noted above, convenience trumps less-convenient 'ideal-ness'. Understood.

Workable Drawers would be a neat design outcome of these exchanges if Posters maintain focus on Real World tests and concerns. I had serious doubts about the efficacy of the old Coleman Cooler, based only on pictures. Those doubts were confirmed above by a 1st person user.

"In theory, theory and practice are the same. In practice, they are not."

~ Albert Einstein ~

[DMcCam]

What excellent posts on the engineering and physics of keeping things cold Engineer Guy! I looked into all the links you posted and frankly the costs of those systems are beyond most to even entertain. To me, $1,000 for a portable refrigerator or cooler is not affordable when an old Coleman 3-way on Ebay costs $125.

When you say, “I had serious doubts about the efficacy of the old Coleman Cooler, based only on pictures. Those doubts were confirmed above by a 1st person user.â€

[Engineer Guy]

I was referring to Coleman user Pete42's Post above of today @ 08:34 ~

I have a coleman cooler somewhere in the garage like the one Len had we used it in pop-up many years ago I just hated buying ice or frozen milk jugs which took up most of the space so I bought a coleman 12/120 volt cooler which works for us we do add frozen stuff to help keep it cold.

My embedded Links are intended to inform about what design Pros have done to get improved performance, as noted in the very-respected Backwoods Solar Site quote I linked re: 3" to 5" of Insulation. I never meant for a person to buy pricy products; just study how they're constructed.

Yet another Truckload [literally] of Thermax was dropped off at my local 'Resource 2000' Recycling Center recently, and I could have gotten full Sheets of 2" Thermax for a song. Guesstimate for 3" Wall Thermax Cooler materials for me: $20-. Look for 'blems' or broken Thermax Sheets if you can.

Not that my 'approval' is needed, but your idea of 2" of Thermax is a good one IF you feel that's the right tradeoff of Food space vs. Insulation 'space'. No argument here from the Peanut Gallery... Will that Insulation level meet your Specs of 5 -> 7 Day performance? I have my doubts, but look forward to your initial Test results.

A small Box of Thermax sealed with, say, Metal Duct Tape holding a small chunk of Ice would be an interesting test to conduct in your Garage or House. See what happens on a small scale, taking care to size the Ice amount to the experimental Box volume in the same Ratio as the final desired Ice Block to Cooler volume ratio. It won't simulate the 'cold' loss inevitable when opening a Drawer, but you could get close in performance evaluation.

Here's the immutable facts as I understand them from decades in the wild World of High Vacuum Chambers... Absent Vacuum-evacuated Walls - and they would crush in from Sea Level Air pressure on the Coleman - there isn't a way now, or back 50 years ago to have a MODEST Ice Block go for your spec'd 'long' Camping Time periods in the Coleman Wall depth pictured in the Thread of last year. Besides the 1st person Pete42 Testimonial above, Len's picture of the Cooler size vs. Ice Container Size - leftover Ice notwithstanding - is a knockout spec even in your own, reasonable design criteria of not having Ice [or super-Insulation] consume 'too much' space. Pete42 confirms what Len's picture tells me: 'lots' of Ice is req'd. Why? There HAS to be 'lots' of loss through the thin, low-R Coleman Walls and construction. Save a few VERY esoteric techniques, 'good' Insulation takes space, period [space = Cooler or Building Wall depth].

That said, I see the entire front Wall on my '5 Day' Igloo Cooler is 1' thick, tops. On the BEST day of Igloo Manufacturing, that's an ~R-7 WITH the 'right' Foamed-in material. This is why you and I are disappointed with that Cooler performance. With the 2" minimum of Thermax construction you're contemplating, you'd get an ~R-16; >double the Insulating performance right off the Bat... Good show!

When temps are only shifting 0.1 F degrees over many minutes, my $20- [on sale] Radio Shack Indoor Outdoor/Thermometer was plenty accurate for noting temp TREND information; not absolute accuracy information of no interest. My Oven Timer was my Data Logger that went off each hour so I could collect Data manually. Test time invested: ~1 hour?

I'm VERY adverse to 'Belly Bumping' on these Forums, and don't go there. The Thread of last year you kindly linked smacked of people defending their point-of-view, devoid of Science and simple Testing like I just did 'fer grins'. So, I DON'T consider what Len posted as Data whatsoever. Not because those Posts lack credible numeric Data, but because of all the 'puffery' and what smacked of defending a 'choice'; facts be damned. As with blowhard Millionaire Pundits on Radio and TV, I dismiss what comes out of the mouths of all such folks instantaneously. If there was old Coleman-supporting Data presented, quite frankly it's lost in the verbal 'noise'; flaming; cap letters; and other incivility infecting that 2010 Thread exchange. Physics and Data are what they are. No need to scream or get pissy about them. Either a block of Ice size 'x' melts in Cooler Brand 'y' over time period 'z' or it doesn't. Test it. Post it here. Otherwise, go shout down some folks at a local Political Meeting.

What Sunfrost, Yeti and Engel have done is what HAS to be done to gain superior [not perfect] performance. If they could replicate some Coleman 50-year old insulating 'magic', they would. See Pete42's Post. There WAS no Physics-defying magic achieved, nor mass Manufactured. SOMEONE in the hard core, 'travel the World' 'Expedition' Camper population would fabricate their own super-Coolers, as they do entire Vehicles. I don't advocate striving for Cooler perfection whatsoever. This is why I suggested things like [only] a 3" Cooler bottom vs. 2" Thermax used elsewhere; centered, or off-centered, Ice Block placement up high; ability to use Water or not; and so on. Krown and Pete42's Beverage Coolers are other known-working Coolers worth emulating on the cheap w/blem Thermax or whatever... See my favorite 'Astrofoil' here, as Hiker Chick mentioned in that 2010 Thread here [same as 'Reflectix']:

Astrofoil

Your Specs above sound super. I chime in with the hope of preventing not hitting your goals by not being aware of the minimum that has to be addressed, as has been by Manufacturers with serious Resources - money and brains - and meet your Specs of interest. Their successes - to be studied and emulated, I think - are why I keep referring to not 'reinventing the Wheel'. If Coleman pulled off what Yeti and Engel have, I'd like to see some simple test results of how and what they did from a dispassionate Owner of an Old Coleman. Otherwise, I fear the present tack is toward creating yet another old Coleman with the 'Old School' Cooler performance Pete42 attests to.

I didn't read the Yeti Cooler Specs [again] before writing this, but I did just now. 2" Poly Insulation Construction w/a 3" Lid and full Gasketing. Bingo! Call and ask them for TD-sized Cooler Performance Data. Betcha they have, and will gladly send, a bunch... What a great 'free' starting point for you.

Yeti Coolers

I'm sitting here typing ~80 WPM in a Solar House I designed after humbly reading up on this topic for >30 years. It's a 1,750 sq. ft. 'Cooler' w/9' Ceilings: R-50 Ceiling Insulation; R-28 Walls; a 6" Slab on R-4 Blueboard to slightly decouple that unmoving Concrete Thermal Mass Floor from Earth temps just a little bit. Insulated Foundation. It was 57 F when I walked in 4 nights ago w/no Heating whatsoever, save Passive Solar Gain. House Temp right now: 67 F. Guess which finger I'm holding up right now toward Middle Eastern Oil Despots?

Energy savings over House lifespan: unknown. Comfort level: Priceless!

---------------------------------

Edit P.S. to DMcCam ~ No apologies req'd below; thank you anyway. My comments re: flaming, ad nauseum, was in reference to the 2010 Thread. Silly, technically-illiterate behavior IMO.

3-way Powered Coolers vs. un-powered [Ice in Cooler] comparisons spin my Head some due to the Apples-to-Oranges comparison, but time and tests will sort all that out. Of sole interest to me would be what Ice in an old Coleman does vs. Ice in a newer Commercial and/or home-built Cooler. Apples-to-Apples. What I read was that Pete42 'moved on' from the old Coleman because of the replacement Ice periodically needed [fundamentally at odds with your 5 -> 7 day design Spec], and the amount of space that Ice took up. Clarification will help.

[DMcCam]

Thank you E-Guy for the info and clarification. I too never wish to inflame or cause disharmony after all we are just having some on-line fun. Please accept my apologies if I caused you to think otherwise.

Pete42 elected to change to a 12/120-volt cooler because he had different requirements than Len. Len is obviously very happy with the performance he has with the Coleman. It is interesting that Pete42 didn't say that the unit didn't work as well as Len's did (hey Pete please pipe up here). Pete simply didn't like the trade-off of space versus storage and was fine with a powered unit. He also mentions that he augments his powered cooler with frozen stuff to assist in keeping things cold a good idea anyway.

For me, Teardrop Trailers hearken back to simpler times. An icebox fits them better than an ice chest or powered units. It’s a design decision really. Do I think that the Coleman 3-way was extraordinarily better than today's equally priced ice chests; not really, just that they were evidently better than the performance I get from my Igloo. Even with all the things against them, the thin walls, the front door and the high volume for the ice, the design was somehow more efficient. This is what intrigues me about them.

All of the manufacturers you mention are using ‘old school’ designs. Their new ice chest units differ from their older counterparts with new manufacturing methods, use more modern insulation and better seals (the Yeti coolers add more insulation in the lid and sides, good to note). They also add a recessed seal that’s worth emulating. From all the testimonials I read about them on user forums, these additions work well. They also give excellent tips for increasing their effectiveness…very cool. I currently loose almost 50% of my available space to ice. And it sucks digging through it to get to everything inside. For me, loosing only 1/3rd of the space is acceptable.

I think we can beat the ‘Old Coleman’s’ performance by quite a bit through both design and materials. The Coleman was much taller so there would likely be no huge thermal layers to contend with. With 2" of Thermax I think we can get another couple of days out of the general design. Add a layer of Astrofoil (thanks for the reminder by the way) and we might be looking much closer to the 7-day ideal.

I’ve been sketching out a ton of these ideas to see how they could work. By making the access to the ice area separate from the door/drawer we would have less cold air loss. Maybe the ice needs to be loaded from above through the counter top?

Regards,

Dave

[boatyardgirl]

This topic caught my attention!! I am currently took an icebox out of a boat because the owner decided he wanted a 'powered' refrigerator. It is the size of a dorm refrig' ,front opening. If the problem (for him) was keeping food cold it was the lack of insulation!! It is equal to a cheap thin white styrofoam cooler. I have asked for it and plan on putting it in my camper. My thought is to fill the back and sides of the space with as much insulation as possible. Any suggestions or thoughts? Thanx Amanda

[DMcCam]

Hi Amanda, I'd read Engineer Guy's posts about insulation especially Thermax and the use of Astofoil. You'll likely need to add insulation on all sides and to the door. Posting pictures sure helps everyone chime in to give ideas too.

Best,

Dave

[Catherine+twins]

How about some hundred-year-old technology to extend boondocking trips.

Has anyone here heard of the Icy Ball? It uses the amonia absorpiton cycle, similar to what is used in any propane-powered refrigerator, but doesn't cycle continuously. It actually has two balls, one with amonia/water mix, and the other where the amonia alone collects when you "charge" the unit by boiling the amonia out of the water (heat over fire, Coleman stove, parabolic solar cooker, etc). It is charged once a day (okay, maybe twice when you are in really hot weather), then the "icy" ball is put in your cooler with water bottles and such, and the amonia is allowed to bond with the water again (in the closed system of the Icy Ball, not in the cooler) and everything in the chest is chilled (iced). Then you close up your chest and put the Icy Ball away for another day.

No one makes these commercially these days, but there are directions to build one on the web (of course, with all the DANGERDANGERDANGER warnings one would expect when working with high pressure and amonia). Might be an interesting niche market for off-road and boondocking camping enthusiasts.

http://en.wikipedia.org/wiki/Icy_Ball

http://crosleyautoclub.com/IcyBall/crosley_icyball.html

http://crosleyautoclub.com/IcyBall/Home ... Built.html

No, I don't have one, but I plan to. My uncle welds, and although he may not be able to put one together himself, his is intrigued and is talking with his buddies about this "project."

Catherine

[Engineer Guy]

Very kewl! Thanks for posting that. The more things change, the more they stay the same, eh?

I first ran across Solar Collector-based ideas, and ones I adapted for other functions, in '70s Issues of 'Mother Earth News'; 'Practical Homeowner'; and 'Home Power' Magazines. Certainly not as portable - except for a CT Roof perhaps - but see some Articles here:

Solar Collector Refrigerators

Evaporative Cooling Fridge

Not coincidentally, many of the Backyard Wizards published in those Mags live in your Region.

I smelled some 'mysterious' Ammonia odor in my Land Yacht Avion Trailer and innocently opened the Door to the un-powered Dometic Fridge while investigating. Frankly, I'm amazed I still have eyesight. The pressurized built-up Ammonia 'blast' to the face was simply indescribable. Choking, gagging, Oxygen displacement [for breathing], the whole bit... Apparently, the '83 Fridge developed a leak just sitting. The Fridge Mechanicals faced Solar South. So, nicely-sealed, internal outgassing built up as the vented Fridge enclosure w/Coils Solar-heated up.

We all muck with Propane, Electricity and 'stuff', so no big deal... The Nose is a phenomenal Leak Detector and beats any electronic one I've used.

At massive Particle Accelerators like CERN in Switzerland/France, we used screw-in over-pressure Relief Valves for last resort emergencies. It was like thick Aluminum Foil captured in a little fitting. Consider putting on some type of beefier over-pressure Relief Valve that releases only in an emergency, well above the expected high pressure limit. Put it in a threaded fitting so that it can be replaced. Once installed, it will never be used.

I worked with a huge Refrigerator Manf. in Decatur AL to improve Refrigerator Assy. throughput. We put Vacuum Gauges on Compressor/Coil Assemblies. On a powered, motorized track, the Assemblies swung along like Beef Carcasses from an overhead Rail. ~20 minutes later, if the Assemblies coming back still held 'Vacuum', they were good. Finding soldered fitting leaks later on was VERY expensive in Fridge Production. Old news to your Uncle might be to use an inverse technique. Pressurize what he welds up and watch it over time on an Air Pressure Gauge in a fixed temperature setting. No decrease in pressure readout = no leaks of consequence. Soapy water leak checking works, too.

We get a nightly wind at 6,100' off the 10,500' Grand Mesa just behind us. As heated Air down in the Valley below rises and creates a relative Vacuum, the replacement Air rushes off the Grand Mesa and knocks over light Lawn Chairs some nights. Then, it stops about 2 A.M.. I plan to seasonally cycle our 6"-thick Slab Radiant Floor Tubing out to passive Radiators to cool the Floor all night to coast through the next ~100 F Summertime day. This idea of such Chillers is commercialized in High Vacuum Coaters. For a Fridge, you might be able to similarly chill mass down in a recycled 'dead' Fridge w/additional Insulation, per the U.K. idea above. Pond Water sprayed on Chiller Coils would cool more via Evaporation. Power the circulating Pump on a little PV Panel, and you're good ta go.

[DMcCam]

Thanks for the links Catherine and E-Guy, very interesting tech. The ammonia water system is amazing. I can see its attraction for off-grid applications. The British girls story reminded me about a 1970's British icebox company that used evaporative cooling panels in their design. If memory serves, the unit used a wicking material that dipped into water trays. Why not use the ice melt to feed such a system? The idea has merit for sure. No moving parts and powered by heat; boy is that turning a disadvantage into an asset.

Amazing stuff here.