Off grid A/C solutions?

This confounds me to no end.  

Everything I research amazes me and shows just how much of a hermit I've become.  There are incredible inventions and solutions for everything!  YouTube videos about everything from new tech to DIY redneck solutions leave me in awe at what's possible!

Except when it comes to off-grid air conditioning.  Nothing.  Nada.  Zilch.  Zip.  Goose egg.  Sure, there are things like swamp coolers and zip tying bottles of frozen water to the front of a fan but, let's be honest.  Those aren't effective long term solutions and they aren't really that great or effective without your face a few inches in front of the thing.  And still, those need electricity.

With all the ingenuity and creativity in the world, not to mention technological knowledge, why aren't there any solutions for off-grid A/C?  They're so non-existent that there's not even an A/C forum on Permies that I could find.  I know you can run A/C on solar, but that requires a LOT of solar and battery storage.  It works, but it's not ideal.  

I'm a heat wimp, folks.  Anything above 70°F and I'm as baked as an Easter ham.  I actually get physically nauseous when I get hot.  It's the only thing that causes me to question ever going off-grid.  Whoever solves this problem is guaranteed a front row seat in heaven, surely.

Air conditioning takes a good deal of electricity.  I have managed to run a 5000 btu unit in my basement off of my 12v system converted to 110.  The trade offs are significant.  The problems come in with how long it runs, cloud conditions, and if I want to run anything else.

 I just noticed your comment on being a heat wimp.  I put my expectations for my basement at 80 and a lowered level of humidity. Even then, it can be a challenge.  I have around 2500 watts in panels with questionable lead acid batteries.  

This seems like an important issue for you from your post. We feel equally as strong about the cold weather.

Where we are currently is about as far north as I would want to be. For you, you may want to figure out how far south you are willing to be based on temperature. That may help inform your relocation and negate the need for AC or reduce it significantly.  

Edited to paste this post you may want to read:

https://permies.com/t/157903/sans-air-conditioner-central-Oklahoma

AC always seems like a last ditch resort for bad design to me.

More permie solutions might include things like wofati, or passive solar, or even just better insulation.

Here's a couple of videos...

A while back the forum had some discussion along this idea.

I didn't find the thread I was looking for though this one talk about using soda bottles:

https://permies.com/t/13565/electrical-refrigeration-freezing-air-condition

There is a guy out in West Texas that lives off grid and has developed a system using an ice chest.

I am not sure it is in this video though:

Emmett Ray wrote:This confounds me to no end.  

Everything I research amazes me and shows just how much of a hermit I've become.  There are incredible inventions and solutions for everything!  YouTube videos about everything from new tech to DIY redneck solutions leave me in awe at what's possible!

Except when it comes to off-grid air conditioning.  Nothing.  Nada.  Zilch.  Zip.  Goose egg.  Sure, there are things like swamp coolers and zip tying bottles of frozen water to the front of a fan but, let's be honest.  Those aren't effective long term solutions and they aren't really that great or effective without your face a few inches in front of the thing.  And still, those need electricity.

With all the ingenuity and creativity in the world, not to mention technological knowledge, why aren't there any solutions for off-grid A/C?  They're so non-existent that there's not even an A/C forum on Permies that I could find.  I know you can run A/C on solar, but that requires a LOT of solar and battery storage.  It works, but it's not ideal.  

I'm a heat wimp, folks.  Anything above 70°F and I'm as baked as an Easter ham.  I actually get physically nauseous when I get hot.  It's the only thing that causes me to question ever going off-grid.  Whoever solves this problem is guaranteed a front row seat in heaven, surely.

I think you're missing most of the picture here. There are lots of ways to have AC off grid. Personally I have been off grid for 17 years and I run my AC all summer long during the days and at night when needed. I have health issues that don't deal with temps out of a range of 50-80f well at all.

There are also other ways to live IE: underground then you're only cooling and heating from ground temperatures which here is 58f.

Male sure you look at other options you can't think straight line here but it can and is done all the time.  

John F Dean wrote:Air conditioning takes a good deal of electricity.  I have managed to run a 5000 btu unit in my basement off of my 12v system converted to 110.  The trade offs are significant.  The problems come in with how long it runs, cloud conditions, and if I want to run anything else.

 I just noticed your comment on being a heat wimp.  I put my expectations for my basement at 80 and a lowered level of humidity. Even then, it can be a challenge.  I have around 2500 watts in panels with questionable lead acid batteries.  

The best solution I have so far is putting a cot in the root cellar that's below the basement.  At least it's not an emergency situation for me.  Just one I'm planning to be prepared for if staying on the grid becomes problematic.

I asked ChatGPT to rank, in order, all the different kinds of batteries that store solar power.  Here's what it gave me:

1.  Lithium-ion Batteries – Best for effectiveness, efficiency, and storage capacity.
2.  Flow Batteries – Best for large-scale systems but still less efficient and more expensive.
3.  Saltwater Batteries – Great for environmental impact, but less efficient and bulky.
4.  Lead-Acid Batteries – Affordable but less efficient and have a shorter lifespan.
5.  Nickel-Cadmium Batteries – Durable in tough conditions but lower efficiency and toxic.
6.  Sodium-Ion Batteries – Emerging tech with potential, but not yet competitive with lithium-ion in performance.

(I've also found ChatGPT to be wrong on more than one occasion.)

Emmett Ray wrote:

John F Dean wrote:Air conditioning takes a good deal of electricity.  I have managed to run a 5000 btu unit in my basement off of my 12v system converted to 110.  The trade offs are significant.  The problems come in with how long it runs, cloud conditions, and if I want to run anything else.

 I just noticed your comment on being a heat wimp.  I put my expectations for my basement at 80 and a lowered level of humidity. Even then, it can be a challenge.  I have around 2500 watts in panels with questionable lead acid batteries.  

The best solution I have so far is putting a cot in the root cellar that's below the basement.  At least it's not an emergency situation for me.  Just one I'm planning to be prepared for if staying on the grid becomes problematic.

I asked ChatGPT to rank, in order, all the different kinds of batteries that store solar power.  Here's what it gave me:

1.  Lithium-ion Batteries – Best for effectiveness, efficiency, and storage capacity.
2.  Flow Batteries – Best for large-scale systems but still less efficient and more expensive.
3.  Saltwater Batteries – Great for environmental impact, but less efficient and bulky.
4.  Lead-Acid Batteries – Affordable but less efficient and have a shorter lifespan.
5.  Nickel-Cadmium Batteries – Durable in tough conditions but lower efficiency and toxic.
6.  Sodium-Ion Batteries – Emerging tech with potential, but not yet competitive with lithium-ion in performance.

(I've also found ChatGPT to be wrong on more than one occasion.)

 For long term off grid LifePO4 are the cells you want!

Josh Hoffman wrote:This seems like an important issue for you from your post. We feel equally as strong about the cold weather.

Where we are currently is about as far north as I would want to be. For you, you may want to figure out how far south you are willing to be based on temperature. That may help inform your relocation and negate the need for AC or reduce it significantly.  

Edited to paste this post you may want to read:

https://permies.com/t/157903/sans-air-conditioner-central-Oklahoma

Yes and no.  It's a big deal because I hate heat and humidity.  But, it wasn't a deal breaker when I was choosing where I wanted to relocate to permanently because I will be on the grid, even as rural as I'll be.  I just want to be prepared in advance to go off-grid if needed.

I love the cold.  I really do.  We're below zero and have been that way quite a bit.  Throw in the wind chill factor and we've hit -50°F.    Even that doesn't bother me.  Winter is just free air conditioning!  And heating a place is a whole lot easier than cooling it.  But, other factors ruled out colder states for me.  A big one being that I am DONE as I can be with snow shoveling.  It's part of my current job and they're so strict about it that I'm just OVER IT!  I'm often outside in the middle of the night shoveling.  I'm out there in life-threatening and dangerous cold temps because they don't care about that.  I've gotten bronchial pneumonia and frostbite but that doesn't matter to them.  My phone has shut down for days because I'm required to take pictures after I shovel.  They just don't care.  That's the city for you.  

My two compromises for where I'm moving to are the heat and humidity, and chiggers.  Everything else is perfection for me.

Thanks for the link!

Burra Maluca wrote:AC always seems like a last ditch resort for bad design to me.

More permie solutions might include things like wofati, or passive solar, or even just better insulation.

Here's a couple of videos...

Thanks, I'll check those out!  I've heard of a walipini but not a wofati, so I'm eager to study that, too.  
The construction of the house will be in stone.  Thick walls, like English Victorian and Edwardian eras.  As for insulation, I'm going with sheep's wool.  I've really looked into it and, for the area I'll be in, it's ideal.  It will definitely help keep the house cooler in the summer, too.  

Anne Miller wrote:A while back the forum had some discussion along this idea.

I didn't find the thread I was looking for though this one talk about using soda bottles:

https://permies.com/t/13565/electrical-refrigeration-freezing-air-condition

There is a guy out in West Texas that lives off grid and has developed a system using an ice chest.

I am not sure it is in this video though:

Advice I received from my elders that's served me well is:  "You ought to always listen to folks who've been down that road before you."    I'll definitely check out this guy.  I'm not lazy, so I'll find the video you mentioned.  Thanks for the suggestions!

larry kidd wrote: I think you're missing most of the picture here. There are lots of ways to have AC off grid. Personally I have been off grid for 17 years and I run my AC all summer long during the days and at night when needed. I have health issues that don't deal with temps out of a range of 50-80f well at all.

There are also other ways to live IE: underground then you're only cooling and heating from ground temperatures which here is 58f.

Male sure you look at other options you can't think straight line here but it can and is done all the time.  

I'm all ears, Larry.  I'd love to know how you have constant A/C all summer.  I'll have a root cellar that's underground, but that's about all.  Like I said earlier, I'll at least make sure there's room for a cot in there so I can at least sleep.  

I've been a hermit for so long that I'm afraid my line of thinking isn't as flexible as it was when I was younger and more creative.  That's why I joined this site and I'm glad I did.

larry kidd wrote:For long term off grid LifePO4 are the cells you want!

Never heard of them.  I just put that in my notes to look into.  Thanks big time.  

ive recently installed a smart circuit which turns on smart sockets around my offgrid farm when my batteries are at 100%, this is to irrigate a field, heat a water tank and heat a room. i am going to extend it to an ac unit that heats as well.
so when my batteries are at 100% one of these devices turn on, and when my batteries from below 100% the device turns off. great way to use the excess energy

Emmett Ray wrote:

larry kidd wrote:For long term off grid LifePO4 are the cells you want!

Never heard of them.  I just put that in my notes to look into.  Thanks big time.  

Just noticed you're moving to the foothills of Appalachia which is where I'm at in Virginia.

There are a huge number of answers.  

Geothermal cooling for everyone with the ground temperature for it.  I am going to say northern 2/3 of US and most of europe this applies to.  This is not heat pumps.

Desiccant air conditioning is another one.  Capable of working almost anywhere.  But the dream system here would probably be best used with the above.

Radiant cooling using solar panels at night.

Radiant cooling paint or cooling materials

Solar thermal air conditioning.  Would have to be stacked with other systems but could give the final edge.

Heat pipe systems

Will try and get back and post a bunch of links.

There are mini splits that run directly off solar panels.


https://signaturesolar.com/eg4-hybrid-solar-mini-split-air-conditioner-heat-pump-ac-dc-12000-btu-seer2-22-plug-n-cool-do-it-yourself-installation/


https://airspool.com


Or you can build an earthship home.....  


There are 12v mini splits for those living out of their vans..

Plenty of options, but they do cost money and time and sometimes much sweat.

larry kidd wrote:

I think you're missing most of the picture here. There are lots of ways to have AC off grid. Personally I have been off grid for 17 years and I run my AC all summer long during the days and at night when needed. I have health issues that don't deal with temps out of a range of 50-80f well at all.

Larry, do you use solar or a generator for your A/C?

Our daughter has an off-grid AirBnB with A/c.  Folks staying there are warned it is only good for a certain time frame.

Then there is the option for earth tubes or a greenhouse:

https://permies.com/t/44786/Underground-Greenhouse-Earth-Tubes

Then there is the option for a Generac:

https://www.tractorsupply.com/tsc/product/generac-powerpacttm-series-75-6kw-air-cooled-standby-generator-steel-enclosure-8-circuit-lc-1339732

Anne Miller wrote:

larry kidd wrote:

I think you're missing most of the picture here. There are lots of ways to have AC off grid. Personally I have been off grid for 17 years and I run my AC all summer long during the days and at night when needed. I have health issues that don't deal with temps out of a range of 50-80f well at all.

Larry, do you use solar or a generator for your A/C?

Our daughter has an off-grid AirBnB with A/c.  Folks staying there are warned it is only good for a certain time frame.

Then there is the option for earth tubes or a greenhouse:

https://permies.com/t/44786/Underground-Greenhouse-Earth-Tubes

Then there is the option for a Generac:

https://www.tractorsupply.com/tsc/product/generac-powerpacttm-series-75-6kw-air-cooled-standby-generator-steel-enclosure-8-circuit-lc-1339732

I use both solar and generator, mostly solar. Cool tubes are a tried and true method as well. With enough power storage a generator is seldom used...

Josh Hoffman wrote:
Edited to paste this post you may want to read:

https://permies.com/t/157903/sans-air-conditioner-central-Oklahoma

I wanted to build a little bit on this. If you approach "off grid a/c" with unlimited resources, it can be done. No matter the solution, it will cost dearly. Well, what would come to me dearly, at least.

Our years of RV travel had us "boondocking" very often with no utilities. We still live in the same RV. It is parked under our barn during cold and hot weather. Otherwise, it is outside. We have 1140 watts of solar and 300AH of LIPO4 batteries. We can pretty much do whatever we want except ac and hot water heater. We have propane, if needed, for the the H2O heater.

We just opened the RV up in hot weather and acclimated or we moved further north. Here, we open the RV up and stay outside, in the shade if necessary, until sundown. If the humidity is high, we will take a quick cold shower. It is amazing how much more comfortable you can be after one of those quick rinses in the evening.

We also have a 2000 watt gas generator as a backup but did not use it often. Even in partial sun, our setup did very well.

You will pay dearly for the battery storage or the fuel and fuel storage to have "off grid a/c". Maybe revisit it after you invest in the things that are higher on the priority list. Get your property, spend a year or two there, spend a lot of time outside. Find out how much you really want the a/c.

It sounds like you'll be on the grid anyway so you could kick this can down the road.

Check out this permies thread: https://permies.com/t/258863/tech/DIY-Supermaterial-Save-Heatstroke-house

I'm pretty sure at least a couple of permies experimented with it. You would still have to have a way to recharge it.

Look for a property with a cave - there are caves which keep constant temps, but then you'd need to light it somehow... there's always a catch! Something to do with physics and entropy!

It does sound as if you might want to also research "ice houses" and how people kept ice stored for long periods. If you're already planning an underground cold cellar, having a second area designed as a well insulated icehouse might not be too big a stretch.

Born and raised in the South, but since 1980 have lived in CA...mean streets of LA area and near Big Bear above 8k feet....also Hawaii, coastal WA, Czech Republic,  Thailand and a few more.  Yes our home here in GA is roasting at times but we all survive by remaining humble. Hence the famous phrase " if it's not the heat it's the humility "

I lived without ac throughout my Southern chikdhood then again for 7 years of my adult suffering.  It only hurts if you think about it obsessively , or you don't give it a good long patient time.  I believe we all have something of an internal thermostat.   When night Temps were 100, for example,  I kept my bed sheets in the freezer until the last moment. Another low tech way to sleep was placing my old boy scout canteen in fridge or freezer, then stretch out at night while balancing the frosty metal on my chest.  On the bright side, my power bill was often 18 bucks per month.

Off grid living was a bit tough but strategies helped.  Rammed earth walls and proper window placement were key to my success over the decade I tried that. I am sure you do this, in shape or form, lots of crafty suggestions on this thread.  Live long and prosper my friend
Rico.  

Sorry, 17 years of my adult suffering.  My wife put a stop to that nonsense eventually

Gasifier to generator to A/C but only air conditioning a small, very well insulated area.

I am not sure how serious you were about temps above 70 making you nauseous. If you are being literal, that mean no room for failure for a big part of the year, as you can't fix anything when you are nauseous. So in addition to the gasifier, a solar generator as  back up to the gasifier generator.

Might be easier to choose a colder climate and warm a greenhouse to grow what you want than try to maintain a sub 70 degree living space in that area.

Those Russian/Chinese trench greenhouses can do amazing things. No nausea.

Emmett Ray wrote:  With all the ingenuity and creativity in the world, not to mention technological knowledge, why aren't there any solutions for off-grid A/C?.

It sounds like you have your home-building plan set, but if you have the option, you may want to consider SIREwall, as air conditioning is not needed (nor heating, although fireplaces are so homely!).  
This video has a simple overview, but there is so much more: https://www.youtube.com/watch?v=ra4Pldetd_M
SIREwall means "Stabilized-Insulated-Rammed-Earth Walls", and the benefits are incredible and almost unmatched by any other building method (that I have yet to learn).
https://www.sirewallusa.com/wow

If you can't build a SIREwall, perhaps researching various "Passive Cooling" methods, like "Wind Catchers" (aka Badgir or Malqaf), wind towers, earth air tunnels, and narrow housing for cooling could provide viable options for you.  Passive cooling requires no electricity, as it was a technique used from ancient times up until electricity was commonplace.  Simple things like transom windows, linear homes, etc. - and the Amish also have practical ideas, of course without using electricity.  
Helpful passive housing video: https://www.youtube.com/watch?v=UB_ima2t_xU  (btw, was cool to see an entire shopping center built with no heating/cooling!)
This article has great information: https://www.sciencedirect.com/science/article/pii/S2666123320301070

Basically, let nature do the work for you!

Hi Emmitt,

I know that I am late to this thread, but there was something that was itching in the back of my mind that I couldn’t quite put a finger on until now.  The concept is called passive solar cooling and involves utilizing something called infrared cooling paint.  Basically, the physics involved relate to the fact that some substances radiate heat at wavelengths that pass right through the atmosphere with basically no resistance.  Even better, other wavelengths that strike the surface get converted to this specific wavelength (somewhat like the way a glow-in-the-dark pigment works).  Ironically, this works best on a bright, sunny day (although, a cloudless night is spectacular!).  Simple, at-home tests show that a panel painted with this substance (barium sulfate—so harmless that it is used in hospitals as a GI imaging tool—in the form of a milkshake!  That’s right, you can eat it!) in full sunlight on a cloudless day is actually 3 degrees lower than the ambient temperature!  And that effect gets quite a bit better at night.  


I have even seen systems where this was incorporated into a water-cooling panel.


Perhaps something like this would be helpful.

Try searching “Infrared cooling paint”


Good luck,

Eric

Emmitt, Everyone

Here are some links I found for cheap, low power a/c.  The first two involve radiant cooling.  The third involves a sort of (self-contained) chemical reaction (don't worry, its a safe chemical--calcium chloride) that not only cools but also dehumidifies.  Maybe these are worth a look.

https://www.youtube.com/watch?v=dNs_kNilSjk&t=5s

https://www.youtube.com/watch?v=5zW9_ztTiw8

https://www.youtube.com/watch?v=7w4rg3UcsgI



Good luck!

Eric

Emmett Ray wrote:This confounds me to no end.  

Everything I research amazes me and shows just how much of a hermit I've become.  There are incredible inventions and solutions for everything!  YouTube videos about everything from new tech to DIY redneck solutions leave me in awe at what's possible!

Except when it comes to off-grid air conditioning.  Nothing.  Nada.  Zilch.  Zip.  Goose egg.  Sure, there are things like swamp coolers and zip tying bottles of frozen water to the front of a fan but, let's be honest.  Those aren't effective long term solutions and they aren't really that great or effective without your face a few inches in front of the thing.  And still, those need electricity.

With all the ingenuity and creativity in the world, not to mention technological knowledge, why aren't there any solutions for off-grid A/C?  They're so non-existent that there's not even an A/C forum on Permies that I could find.  I know you can run A/C on solar, but that requires a LOT of solar and battery storage.  It works, but it's not ideal.  

I'm a heat wimp, folks.  Anything above 70°F and I'm as baked as an Easter ham.  I actually get physically nauseous when I get hot.  It's the only thing that causes me to question ever going off-grid.  Whoever solves this problem is guaranteed a front row seat in heaven, surely.

Small efficient window a/c unit powered by battery/inverter/solar array. Place unit in a highly insulated small space (a cool room -probably where you sleep is best). Next, power a small chest freezer packed with water bottles. Provide small duct work with a dc blower to direct cool air to wherever you happen to be sitting.

If your home is a very modest size and well insulated, then cooling the entire space with a small a/c unit on a solar array is now a practical alternative - in most settings. Selecting a small generator and operating it properly to minimize fuel use can be used to augment solar including providing backup power during inclement weather.

I manage an estate where the main house summer cooled is done by well based geo thermal.  it's a big nut upfront for minimal operational cost.  the advent of mini splits have pretty much killed small scale geothermal projects.  that might be your answer, mini splits.

there are some architectural things, but I'm not sure if they solve heat or humidity issues.  or if the difference matters.  thick walls and large overhangs.  double roof/ceiling, inner one curved and perforated and the outer one either curved askew or angled.

Dane, I am with you.  Mini splits are getting more efficient,  the upfront costs easier to swallow as they sip energy over time. We had a Mit....shi lasting 17 years with no problems at all.  Lightning finally killed it.  Our new Sam...g is quietly working away with generous 10 years warranty.  We really just need this system for summer in sunny Georgia

Also Dane is correct, start out with just cooling bedrooms.  Living in the tropics for two years convinced us, you can handle any heat by day if your nighttime revery is blissfully cool.  We had several cold showers each day in the tropics, and living spaces in our house just used small fans.  You eventually get acclimated.  
My two ice cubes.  
Rico

I wonder if, at least for the time being, progress might be made by thinking of how to cool your body as such, as contrasted with cooling the entire living space.  Personally I've found that water is the solution....turning a hose on myself as I'm working through a hot day; or better still having a body of cool, shaded water to dunk myself in multiple times a day.  This made a central Georgia bush homestead, where I lived the first four years in a tent, much more endurable!  Cooling a bottle of homemade wine in the water for the end of the day helped too

Like the others here I would recommend some sort of subterranean air circulation, lots has been done in the realm of passive greenhouse cooling - one thing to keep in mind is that in high humidity it's possible to get mold growth in the underground pipes so it's good to have a way of cleaning them. Look into Earthship passive cooling, the approach is to use convection to pull cool air into the building by venting the hot air through the highest point in the structure and it generally seems to be pretty effective.

As far as more traditional A/C systems, the lowest power ones I've been able to find utilize indirect evaporative cooling; essentially a swamp cooler that keeps the evaporated water separate from the cooling airstream, such as the M-Cycle design https://www.achrnews.com/articles/108864-the-m-cycle-based-cooling-system - these essentially only require electricity to run the fan to circulate air and as such require significantly less power than standard air conditioners relying on compression cycles, however they have the major limitation of decreasing effectiveness with increased outside humidity (although this can be solved via a dessicant/dehumidification system prior to air intake). The other issue is that these seem impossible to buy anywhere. At one point there was a company called coolerado making these but they appear to be discontinued: https://www.youtube.com/watch?v=PHSuFmmHpDM. A guy in Dubai has been 3d printing them and appears to be having some success https://www.youtube.com/watch?v=r7LITeqLLwY, I might attempt to build one of these at some point in the near future for my partner's camper van (if I ever have the time haha) and will make a post here if I have any luck recreating the design. Here's an example configuration with a dessicant wheel inline for humid environments: https://youtu.be/RqS6TXI-Nj4?si=1Pwjr5vQWqavVQCk&t=378

Direct sky cooling is another option (essentially materials which emit thermal radiation in a bandwidth that can escape earth's atmosphere, although these generally don't work nearly as well as standard A/C), several people have created formulas for a paint which can be created, however there is question about the long-term durability of these panels : https://www.youtube.com/watch?v=KDRnEm-B3AI

Another potential avenue for person-level cooling is phase change materials which don't require much additional cooling, although again there is the question of long-term durability: https://www.youtube.com/watch?v=Nqxjfp4Gi0k&t=1069s

The bottom line is that any steps you can take to optimize your house / space to make it generally cooler in the first place will be very beneficial, some best practices are things like: controlling airflow through the space efficiently, ensuring solid insulation and thermal mass, building partially buried structures (with extreme caution, working in even shallow holes is deceptively dangerous), having shades/awnings over windows, really any steps to prevent heat from entering the structure in the first place.

Hope you're able to find something that works, I second your frustration at the lack of a comprehensive off grid air conditioning approach

Emmett Ray wrote:This confounds me to no end.  
I know you can run A/C on solar, but that requires a LOT of solar and battery storage.  It works, but it's not ideal.  

I'm a heat wimp, folks.  Anything above 70°F and I'm as baked as an Easter ham.  I actually get physically nauseous when I get hot.  It's the only thing that causes me to question ever going off-grid.  Whoever solves this problem is guaranteed a front row seat in heaven, surely.

If you break down your issues and look at it from a slightly different perspective, you can rephrase the issue as "How to I stay cool and comfortable off-grid?"

Solar aircon works well during the heat of the day when you need it most.  If you try to use solar ac when the sun doesn't shine, it gets very expensive very quickly.  I think most of us can agree in most environments, early morning and LATE afternoon can be acceptable without aircon.  To me, the real problem is how to get through the peak heat of the day and then how sleep comfortably.  My approach, in "development" is as follows:
* morning - fans running on solar charged batteries, a single 100-200ah LiFePo batter can easily handle this off of a 300W solar panel
* late-morning thru early/late afternoon - solar aircondtioning, ability to run into the later afternoon/evening is entirely dependent on investment you're willing to make in batteries and additional panels but looks to be roughly $250 per hour you want to run when sun is down ... this is all assuming something like a 400-500 ft2 area
* evening - chilled mattress pad.

For the chilled mattress pad, there are a variety of commercial options but either require meaningful electricity (though still MUCH less than traditional ac) and are both expensive to buy and maintain in the long run.  I've already put together a trial unit that works perfectly well at 1/3 - 1/4 of the cost of commercial options and is very inexpensive to maintain.  My wife actually complains that she's a bit too chilled.  We comfortably sleep through the night on >80F nights with no ac.  Approximately 12lbs of frozen salt water in old milk bottles (with a 6F freezing point) will chill water sufficiently for 8 hours of nice, chilled mattress.  I split a cooler into two parts and use the frozen salt water in the larger portion to hold chilled water and a radiator to maintain the temp of the smaller portion of the cooler that uses waterbed softened water to circulate thorugh mattress pad.  My plan is to use a solar freezer to freeze the water bottles during the day then transfer to bed cooling system. This isn't as complex as it seems ... I just throw the bottles in the freezer each morning and then back in the chilling cooler each evening (using regular wired kitchen freezer for now).  

Going off-grid shouldn't be doing exactly what we do today, it should be using innovative approaches to solve our problems.  My approach above is a bit of a hack, but I've proven the hard part (non-battery intensive solution to staying cool at night) and the rest is pretty proven technology.