DIY Solar Air Conditioning Unit

The sun is great, and vital to nearly all of Earth's processes.  What bothers me is that the sun also makes the air really hot!  As a result, millions of people turn to air conditioning to cool their homes, cars, offices, etc.  Traditional air conditioning units use massive amounts of energy, making electricity bills skyrocket in the summertime. 

What if there was a way to cool your home, car, or workplace without the need for a big, loud, and energy-hungry machine?  What if this device also was entirely solar powered with no moving parts?  Sound to good to be true? 

This Instructable will cover the method I used to build a prototype Solar Air Conditioning Unit.  This unit is a prototype, and was only ever meant as a proof of concept that my idea could work.  There is a lot of testing that needs to be done to see how this idea can be used in more practical applications.
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Index:

• Introduction
• "Why?"
• Theory of Operation
• Gather Materials
• The Build Pt. 1 - Cutting Wood
• The Build Pt. 2 - Gluing
• The Build Pt. 3 - Metalwork
• The Build Pt. 4 - PVC
• The Build Pt. 5 - Miscellaneous
• Using the Unit
• Going Further and Conclusion
• Videos!

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.:| This Instructable was intended to be entered into the Green Technology Contest.  However, because this project uses no electronics, it was not accepted.  I entered this into the Hurricane Laser Contest instead, and if you like this Instructable, it would be awesome if you would vote for it in the contest!  Having a laser cutter would be awesome because it would allow me to build things better and more quickly to be able to share them with the community! |:.
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7/17/2012:  Thanks so much for the feature!!

Step 1: "Why?"

I wanted to try to keep the Intro fairly short and sweet, and more formal.  But why build this, at a personal level?

-I'll take this point to say that if you don't care about specifically why I built this, then move on to the next step, no hard feelings : )

My car sits in the sun all day, and has a black interior.  I'm sure you already know that dark colored things tend to get hotter when they sit in the sun than lightly colored things.  Additionally, windows do a funny thing when light hit them, and serve as a sort of insulation, so that the air in my car actually gets hotter than the outside air temperature.  Both of these factors cause me to start sweating almost immediately upon entering my car, which isn't very attractive when going to work, nor very comfortable.

Therefore, I was thinking of different ways I could cool down my car while it sits in the driveway.  Leaving all my windows down isn't very practical for safety reasons and letting bugs in.  A foil sun shade that would sit on my windshield would be annoying to put up and take down.  I also had a vague idea of how a Solar Air Conditioning Unit could work, and decided that a car would be the perfect test medium for my concept!  The car would allow me to attempt to cool a small amount of space, in a fairly controlled setting, and potentially save me from a very uncomfortable commute.

Comments

[aniltvmin]

I have previously asked for the videos for some clarification, and happy to find it now. I couldnt start the project without it. Thanks....I will update after i try..

Also expecting your updates about any improvement or addition..

[Redstormx1]

Im glad your using your brain and trying to thinks of idea. Even though this might not be the easiest and simplest idea. you can take what you learnt from it and use it in the future for something else. You got some handyman skills there.
I was thinking Get some kind of air scoop so when you drive it directs the wind inside the car. Then have a wet medium infront of it . And mybe a bottle of water and a pump which sits under the seat and pumps new water to the unit.
The car would cool down pretty fast after a few mins of driving .
IF you have any questions im an air conditioning mechanic .

[Ranie-K]

Author: What do you think about this idea?

[shannonlove]

I wouldn't worry about high precision in this case. Getting down to the nearest degree is more than sufficient. Don't do more work than you have to. Adding needless precision also adds the risk of additional error. Learned that one the hard way after mis-measuring hundreds of blue crabs with needlessly precise calipers which I misread.

I would recommend cooking thermometers like the kind they sell to make candy. They have a wider upper range than weather thermometers, they are more durable and, most importantly, you can calibrate them using boiling water (corrected for barometric pressure of course.)

[fozzy13]

Hi there!! : )

I considered using candy thermometers, however they can be $10 or more, and so I didn't want to buy them when I'd only really be using them for these measurements.. I also wasn't sure how accurate/reliable they would be hanging in air, as opposed to being submerged in a syrup.

Thanks for the read and the comment!! : )

[static]

I use the ~ $5 digital food thermometer in Walmart's kitchen accessories section. Unless you are working with serious critical chemical reactions, their accuracy probably is good enough for the home shop. Good instructable, but a project I would duplicate, you gotta be tough :) Currently it's 102 F outside at a time when are having record triple digit highs. I live in the part of KS swamp cooling works well most days.

[fozzy13]

That's not a bad idea. I actually got a candy thermometer yesterday, so I'll be able to take some measurements soon.
: )

[shannonlove]

$10 bucks is $10 bucks, especially when you are a young student as I remember all to well. Back in my day, $10 bucks was 2 hrs labor at my minimum wage college jobs. However, I also remember wasting a lot of time, money and effort because I guessed at something instead of measuring.

All science begins with measurement. If you can't produce repeatable measurements, whatever you're doing isn't science and probably not even useful inventing/engineering. You can easily end up pursuing dead end design paths because you had to guess whether any particular design or change was really producing the results you thought they did.

I always recommend to people building anything whether woodworking, electronics, software, cooking etc to spend money first on measuring tools. It's the traditional, "measure twice, cut once" wisdom.

Check around. You can get relatively descent infrared thermometers for $20 bucks or so. Also, remember you can borrow tools. Make friends, schmooze and help other out and they will return the favor. When you're working on a shoestring friends are more important than cache.

[fozzy13]

That's right, and I've been working 2-3 jobs all summer trying to save for all the upcoming expenses.. That said, you have a good point about the importance of measurements.

Thanks for your input and comments!! Your help and interest is appreciated : )

[bpfh]

Temperature is temperature, be it in a solid, liquid or gas. What would change would be the time taken to get a distinct reading. The candy thermometers I've seen are heavier than house ones, inside a steel casing with a window to see the temperature, and that would take longer to warm up or cool down in air compared to a plain household bulb thermometer on a plastic mount.

[shannonlove]

You are correct that it would seem like the increased mass of the candy thermometer would make them less reactive but I haven't noticed any issues with them.

Candy thermometers are quite reactive because candy making requires precision as some task like chocolate making will fail if the temperature goes outside a 4F/2C range. On the other hand the thermal mass of water, solids and sugar is enormous so they might be slow measuring just air. I have used them for a surprisingly wide variety of task e.g. checking engine temps (but please don't tell my significant other) and they seem very reactive.

Their major advantage vs weather thermometers is their upper range. Most weather thermometer peg out at around 120F/49C making them useless for measuring any temp you couldn't touch with bare hands anyway. The second advantage is that you can calibrate them with boiling water.

[fozzy13]

Thanks for your input!! I may try to look for some decent thermometers later today!

Thanks again!
: )

[rhooie]

Won't work here in Florida, to much humidity. But putting this thing on every day is easier than a foil reflector?

[fozzy13]

RIght, certainly no help to Florida, unfortunately : )
It's not hard at all to put on, however I can't really say whether or not it's "easier" since I haven't tried a foil shade. It's certainly more fun and fulfilling to put on to say the least : )

[StuNutt]

Don't worry that you've "reinvented" the swamp-cooler - These are very good and very efficient. I had a whole house "air-conned" with one on the roof when I lived in Riyadh, Saudi Arabia, where (being basically in the centre of a large desert) it was hot (up to 115 degrees F or even more) and very dry.

Compared with a "compressor-type" air-con, they cost pennies to run, and made he place more comfortable with the humidification or the air indoors.

I like the idea too of making it "dual purpose" to heat the car in the Winter before driving off - I'm currently doing something a bit similar to stop my workshop in the garden getting too cold and damp at night in the Winter by fitting a "Solar Collector" on the South end, blowing air heated by the sun in the day through a THICK insulated concrete base, which should radiate into the workshop at night and keep the conditions in there a lot nicer.

[fozzy13]

Thank you!! I did have hotter and more arid regions in mind when I thought about the possibility of scaling this project!

Your garden heating project sounds awesome! A great idea for passive solar heat.

Thanks for the read and comment!! : )

[StuNutt]

Hi Fozzy, It's not strictly speaking a "passive solar" system - that's where you just use a large area of South-facing glass (or polycarbonate) to heat the internal structure of a building directly by the sun. It's "active" because I will be using a fan to circulate the hot air captured in the solar collector and circulated through a base of rammed earth and concrete (about 100 cubic feet in my project) which is insulated from the ground below it.

The thermal mass of this base is intended to store that heat and to radiate it from the floor into the building once the temperature inside starts to drop at night. Yes - I've been taking pictures as I've been going, and it will be submitted as an instructible when it's finished . . . . But that won't be for several months as I won't need the heating until later in the year when it starts to get colder at night. I've been neglecting a lot of other chores since I started which I'll have to catch up on!

I've built the workshop with stud wall, OSB skin inside,  which will have the space between the studs insulated with glass wool insulation and twin-wall plastic cladding outside, while the roof is OSB, covered with glass wool and another layer of OSB over that. Should be nice and cozy!

Stu

[static]

Respectfully your definition of passive is much stricter than it is in the general community. In using a solar chimney to create a cooling breeze in a building wouldn't be passive given how you define passive. For most. passive solar means using solar without any other additional energy input to complete the desired task. In the event you could design it to use heat from the sun to circulate the air through the thermal mass in your project it would then be %100 passive.

[StuNutt]

I did think about that for my project, and "hot air rises" - yeah? So if the cold air comes into the bottom of the collector, and goes out of the top, then a pipe from the top of the collector should connect to the top of the concrete storage slab, circulate through it, drop to the lower area of the slab (as it cools, giving up heat to the slab), circulate and then return to the bottom of the collector.

I agree it would work - to a degree, but I'm putting in a "muffin" fan to be able to get the airr to circulate better.

Of course, I MAY find that it circulates enough without the fan, and that will save me having to provide a small power source (probably solar PV) to run the fan during the day.

In fact, I have the air planned to go to the bottom layer of the slab first, as this way the heat should take longer to transfer to the top of the slab (and hence into the structure above, in order to achieve my aim of keeping the building warmer during the late part of the night (electronic equipment does not like cold, damp atmosphere), but it still may work . . . . (?)

Stu

[GordieGii]

If your muffin fan were powered by a solar panel, would that be considered passive?

Gordie

[StuNutt]

Good question Gordie - But I really don't want to get into a lot of semantics. Yes, the muffin fan will probably be powered by solar. I intend to have a small solar PV (about a 10-watt panel) to charge a "float battery", but mainly to allow me to use my ham radio gear in an emergency (I'm a member of the UK ham emergency volunteers) should we have a total power failure. The fan will be powered from that battery-backed supply.

[fozzy13]

Ah! I called it "passive solar", since I thought that term applied to systems that stored solar energy in stone, or in your case concrete.  I guess it does make sense that it's not truly passive if there's a fan involved.

An awesome project nonetheless!  Can't wait to see it!

Thanks! : )

_{(My good friend, the "vote" button, gets forgotten and feels unloved)
: )}

[dll932]

Nicely done. When I was a kid in Arizona "swamp coolers" for houses and even cars were common. There was also flax bags: You would saturate them with water, then fill them up. Hung on your car outside the grille, after driving awhile the water would be ice cold!

The idea of using your apparatus dry creating heat might be useful in the winter.

[fozzy13]

Flax bags sound interesting!! And I'm excited to try using it for heat as well! Thanks for the read and comment!! : )

_{*casually points to the "vote" button in the upper right* : )}

[dll932]

You can still buy flax bags:
http://www.lifestylestore.com/details/ls_detail_6058.html

This is about Trombe walls: Same effect as using your device dry:
http://en.wikipedia.org/wiki/Trombe_wall

[static]

The water bags I recall had a canteen like neck http://www.epier.com/product.asp?1479334 . In the process of keeping the water cool, water in the bag was consumed by evaporation. While they keep the water refreshingly cool, it certainly isn't  ice cold as the other commenter stated.

[dll932]

They're not perfect devices, but I recall using them in 90-100 degree heat in Arizona resulting in very cold water. The basic principle remains the same: Cooling by evaporation.

[tafelice]

Just a note about MDF.
-very susceptible to moisture, and it will swell up to maybe 3 times its size. Not desireable.
-the strength on the face of it is very good, i.e. you want to walk on it or rest things on it. I built a medium duty workbench with it, works wonderful, nice flat surface. I built utility shelves with it, very nice. I did all the wood work in my house with it... OUTSTANDING.
-but it is not structural in that it has very little span, not good on its edge, won't hold a screw (or nail) very well in the edge or even on the face to well, suggest glueing along with screwing/nailing.
-absent of moisture it is extremely stable.
-MDF is VERY heavy

For this project I would almost suggest some type of foam board with hot glue gun. Easier to work with, more resistant to moisture and very economical

[albeem]

Yes MDF is heavy and susceptible to moisture. /You can use GatorBoard foam at 1/2" thickness to construct a rigid, lightweight more waterproof housing. Should paint it. It is a phenolic resin paper sandwich with a styrofoam interior. styrofoam interior wither different than FoamCore.

[fozzy13]

Is GatorBoard available at your average home improvement store at a reasonable price? I'm definitely interested for future projects.

Thanks for the read and comment!! : )

[tafelice]

I was thinking more of R-Max 1/2"

This stuff doesn't have a rigid outlayer but has a somewhat rigid inner core between some silver reflective paper. It has a less than 2% water absorbtion. It is just $9.48 at Lowes. I put this on my basement ceiling and had a ton of big scraps leftover, some of which spent a couple of weeks out in the weather and it came in still in good shape. I read they do a lot of modeling with that gatorboard and perhaps it is a tad more permanent but this R-Max 1/2" would be great for proof of concept projects and I even believe it would hang in there for a good deal of years outdoors, but I can't be certain.

[tafelice]

I guess it is also called R-Matte Plus 3 and I looked up the specs and it is <1% water absorbtion, and can be used between -40f and 250f

It is NON-structural. but for small boxes etc I would try it. I'm thinking of trying a dual chamber swamp cooler using this material.

[fozzy13]

With that low of water absorption and wide temperature range, I could easily look past the "non-structural" label, especially for a project like this.  For this specific application however, the 1/2" thickness would be a bit of an issue, since my car window is thinner than that, but the 1/4" fit very nicely.

I can't wait to see your cooler!

Thanks! : )

[albeem]

This is used in Graphic Arts or TradeShow/ Exhibit displays. Photographers use it for mounting. You might find some scraps or used panels if you check around local companies.

The price is rather high, but here are some sources for single sheets.
Paint edges with latex or acrylic! Maybe 3/16" would be sturdy enough for your use...

GatorBoard
http://www.foamboardsource.com/
http://www.artsuppliesonline.com/catalog.cfm?cata_id=6044

UltraBoard is similar but with plastic surfaces (I haven't tried it):
http://www.tri-dee.com/Ultra%20Board%20Panels.htm

[fozzy13]

Ah, okay, it's too bad that it sounds hard to find. It's good to know it's around though so I can look for it.

Thanks! : )

[fozzy13]

I didn't know MDF was so susceptible to moisture! I chose it because I thought it was made of sawdust and a sort of resin, which I assumed would be more resistant to moisture than plywood.

I don't know if foam board would be quite sturdy enough for this project though, but it wouldn't hurt to give it a shot.

Thanks! : )

[isaacwilk]

I agree with tafelice's comment on using MDF - it's pretty terrible when it comes to waterproofing, and will swell up and turn to mush if exposed. I'd at least paint it, or coat it with something waterproof.

Great idea and instructable though!

[fozzy13]

I will have to do that!! It wouldn't take much to get some clear coat or something of the sort to make it more durable.

Thanks for reading and commenting!! : )

[kjemielity]

great idea,and a well executed instructable.two thumbs up!!!

[fozzy13]

Thanks for the kind words, as well as reading and commenting!! : )

[SAWWAS72]

Could the effectivness of your design be increased by using a small solar powered fan? I just curious.
:-)

[fozzy13]

Yes! It would just need to be placed at the bottom near where the air intake would be.

Thanks for reading and commenting! : )

[Mig Welder]

I commend you for an excellently written instructable with no noticeable grammar or orthographical errors (that's a big deal for me). I'm rather busy with work these days but it's something I'm seriously considering doing for the car that I drive.

Also, I voted for your 'ible.

[fozzy13]

Thanks so much! I definitely tried hard to keep my grammar in check. I'd love to see your version if you get around to making it!

Thanks! I'm really glad you did, I would be ecstatic if I were to win a laser cutter!! Thanks for reading and commenting : )

[tafelice]

I have a generic comment that applies to many instructables. Whenever someone builds something and "they have it already" they count the cost as $zero. This is soooo misleading. Not everyone "has it already." I would encourage everyone who "has it already" to say they have it BUT would cost $1.87 etc. Some instructable writers "have" some very pricey stuff. Just saying.

[graydog111]

I agree with "tafelic" about pricing stuff you already have. I cancelled my subscription to "Mother Earth News" magazine after the cover said it had an article on how to build a free wheelbarrow. In the story, they explained, "Get the nose wheel off a Cessna airplane". Sorry, I could not get one legally.

[fozzy13]

Thanks for your input!! I will definitely take that into consideration when I'm writing my new Instructables!! I hope nothing in the project is quite as obscure as an airplane nose wheel! : )

Thanks for reading and commenting!! : )

[fozzy13]

You make a great point! I've been frustrated at times by the same thing. I would have put the prices on there, however since I didn't buy it, I didn't have a receipt to look up the price, and the prices can be hard to find on Home Depot's website for example, when I can't find the exact product.

Thanks for the read and the comment! : )

[ramatern]

This would work a lot better dual-channel. Make the wet cloth the boundary between an outer channel (heated by the sun, rising as a result, and evaporating the water in the cloth) and an inner channel (cooled by the cold cloth, falling as a result). So the inner channel circulates inside air, cooling it - and the outer channel circulates outside air, evaporating water increasing humidity - which is no problem, since that air is being exhausted anyway. A small solar fan or fans to increase the flow rate in the respective channels could increase the efficiency, at the cost of greater complexity.

My family had a swamp cooler in California that worked this way. The evaporation cooled a heat exchanger - the moistened air did not flow into the building, as it does on many swamp coolers.

[graydog111]

They sold a swamp cooler for cars in the 1930s thru the 1950s. It was a round cylinder mounted on the passenger's side window, outside the car. The force of the air as you were driving passed the air through water soaked excelsor and into the car. It did work, if the outside humidity was low. It only worked when car was moving; the faster you drove the better it worked.

[fozzy13]

That's really cool!! I think it would be more interesting to try to mount one underneath the car, and route the cool air into the vehicle somehow, that way it wouldn't be noticeable, but the air would still flow through it as it moves under the car.

Thanks for sharing, reading and commenting!! : )

[fozzy13]

A dual-channel would be awesome! I didn't think about it as I was building it, however it would be interesting, and fairly easy to add a second channel on the back of the base board.

I had considered using a heat exchanger, but decided not to due to the scale of the unit. : )

Thanks for the read and the comment!! : )

[mgcasella]

Here in Kansas, the temperature has been between 98 and 105 degrees these past two weeks! However, it's been dry heat so I was wondering if anyone knows how to adapt this project to a house?

For example, I live in an three floor, old Victorian, house that is split into three apartments. How many windows would I put this unit in? Could I use it in conjunction with my dehumidifier, fans, or air conditioner for a better effect?.
==

[fozzy13]

Hi there!!
This project would be easy to adapt to a home window! The base board would need to be cut to fit your window instead, and the size of the window box and convection shaft would need to change, but other than that, it's basically the same!
You could definitely use this with your other appliances, and the dehumidifier could help cancel the humidity gained from the Unit.

Thanks for the read and the comment!! : )

[mgcasella]

Would I have to remove the window (I don't think the landlord would like that) or would I simply place this swamp cooler up against it?

We have an old house and the air conditioning works for the whole house, and is quite inefficient. I wonder if there is a way I could use this to save money or if would just end up a hassle?

[fozzy13]

In my case, I just had to roll down my car's window. There will need to be some way for the air from the convection shaft to be able to enter the house. Your specific setup would determine if you needed to remove the window or not.

Thanks! : )

[tbt10f]

It would be more efficient to use an air conditioner than a swamp cooler and a dehumidifier, as a dehumidifier is just an air conditioner with the cold side and hot side merged. see: http://en.wikipedia.org/wiki/Dehumidifier#Mechanical.2Frefrigerative

[aniltvmin]

This is an awesome project....! thanks for sharing....

I am an electronic hobbyist and thats why I subscribe to this site. I used to try and enjoy different projects from instructables, but this is the first time i see a project WITHOUT any electronic part, and still interesting to me....!

I will definitely do this to cool my bedroom. It will be helpful, if you can give more elaborate instructions on how to do it.

I was planning to install a hot air exhaust at the top and an inlet at floor level to get some cool effect. But, your idea will be a better one to try...

I appreciate a video of your current project also.

[fozzy13]

Hi there!!
Thanks so much for the interest! I hope your project goes well, and be sure to post some pictures here when you get it done!!
I may try making a video soon since I've been getting more comments.

Thanks for the read and comment!! : )

_{(The "vote" button in the upper right gets lonely)
: )}

[foreverdisturbed]

I used to work for Thermacore Inc. and we used to build air to air heat exchanger for large outside electronics cabinets for getting the internal air temp as close to the outside temperature as we could. The only moving part was a fan inside and out to move air over the fins. It was made up of 24 thermosiphons with methanol as a working fluid.

[fozzy13]

That sounds like an awesome project! Even if it was for a job, it sounds like fun to me. Thanks for sharing!

Thanks for the read and the comment!! : )

[foreverdisturbed]

I worked there for 18 years and built all types of electronics cooling products and they were all different which did make it interesting and challenging.

[dougbyte]

When I first saw this ible I thought "Now thas about as Redneck as you can get" sorry for pre-judging. This is an awesome idea and it comes at just the right time. My daughter's car is going to be sporting one soon.

Dougbyte
aka Redneck Doug

[fozzy13]

No problem, we all judge, but thanks for the read and the comment!! If you do make one, be sure to post some pictures here, I'd love to see it!

_{(That "vote" button on the upper right looks so nice!  Whoever made the image should be rewarded..)
: )}

[sbappleg8]

I used to like to tinker around making things out of scraps and loose ends but never did I make anything so handy and usefull.

Everytime I read article's from this web site I get the urge to try and find my workshop and start making things that are usefull.

I know my work shop used to be in the basement but I forgot where!

Thank you so much, my wife would love me to do a little cleaning up the junk.
It's not junk as I see from this website it's very usefull treasures.

[fozzy13]

Thank you for the kind words, and the encouragement!! I hope you find that workshop and get to build something awesome!

Thanks for reading and commenting!! : )

_{*Shifts eyes to "vote" button on the top right, smiles and looks away* : )}

[slgibbs1]

I can get pretty much the same effect by opening the windows and the sun roof. The cooler outside air moves in the heat rises and exits out the sunroof...
I used to drive a hatchback and I had to open the hatchback since there was no sun roof.
You couldn't drive with this thing on right? But you made a good effort.

[windshadow]

Having a rear facing opening open during driving could result in carbon monoxide being suctioned back into the car .

[DragonDon]

Given the fact that just about ever major sunroof installation opens like this (http://albertandsonsauto.com/images/sunroofs/sunroof_popup_red_tk.jpg), your statement is illogical. Otherwise there'd be a ton of lawsuits against every major car manufacturer.

We bought a 2000 Neon in 2000, owned it for 7 years, loved the sun roof, rarely used the AC because driving with the sunroof open allowed for awesome airflow inside the car. Use the AC so much that we never got it recharged and it still blew cold when we did use it.

My big question is usability with this design. How easy/reasonable is it to remove and setup? How secure is the car? Too many loose ends to be overly feasible I think. Great idea, loved this stuff, always looking for alternative uses for such things, still needs work I believe.

[fozzy13]

Hi there! For motor vehicles, the usability of this particular setup is minimal. This was definitely a test model and needs to be expanded on. I personally think it could be much better utilized in homes as opposed to cars. However, if it were implemented directly into the vehicles, using the car's windows as the insulating outer box, with the convection shaft and water trough inside the car, perhaps using plexiglass for the base board, then it would be far more practical.

Thanks for the read and comment! : )

[windshadow]

slgibbs1 says:
"I had to open the hatchback since there was no sun roof"

I was not referencing the sun roof.

[DragonDon]

Err, typo:

"Use the AC so much that we never got it recharged and it still blew cold when we did use it. "

Should have said

"Used the AC so little..."

[fozzy13]

I have tried opening the windows and sun roof, and even while driving it takes a good 15-20 minutes until the car starts to get cooler. In the drive way, I don't want to leave them open because of security and bugs could get in.

I wouldn't drive with this on because it would make it hard to see, and could fall off : )

Thanks for the read and comment! : )

[danzo321]

If you spread an old towel on car roof and spill water on it, I think you can more easily cool the interior if you have a few minutes to stand around.

[fozzy13]

More easily? That's quite possible. However like I explained, I used my hot car as an opportunity to test a scalable concept of air cooling.
Are there easier ways? I'm sure!! But for example, it wouldn't be practical to throw wet towels all over the roof of your home to try to cool it, but this concept could be scaled to help!

Thanks for the read and the comment!! : )

[danzo321]

I salute you, but wishing you had started us off with a good diagram of the thing!

[fozzy13]

My diagram skills are clearly lacking, and I thought they applied most to Step 2 when I was explaining the Theory of Operation..
My diagrams looked way better in my head!

Thanks for the read and comment! : )

[schmitta]

Very Nice. You should patent it. It is novel and your particular design would be patentable. You could work one up for a sliding glass door. That would mean you would have a fixed size for the unit so it could be manufactured. Just an idea.

[fozzy13]

Thank you!! I considered applying for a patent, but then again the paperwork and cost of actually doing it seemed overwhelming.

However, I noticed the Jack Daniel's Independence Contest and have been strongly considering getting a patent, making a video, and praying I would win to get some funding to put some units into production!

Thanks for the read and comment! : )

[danzo321]

Normally you cut cardboard to size and shape, and when done, you trace it on something harder to cut. I know because I have made clear acrylic car windows as needed.

[fozzy13]

That would have been a great idea for the window shape!! I didn't have any cardboard laying around, but I'll definitely do that on my next project, so thanks for the tip!!

Thanks for the read and comment!! : )

[shannonlove]

A minor quibble:

Firstly, the movement of water up the fabric is caused by capillary action.  While technically the sum of cohesive and adhesive forces in most liquids, that is not the way it is measured, calculated and termed. People looking to learn more should search on "capillary action" instead of adhesion and cohesion because the latter terms are seldom used in reference to water. 

Secondly, a surprising amount of the cooling done by this system will actually be performed by compression and then decompression of the air as it is drawn through a narrow opening into the bottom chamber and then allowed to expand. 

This latter effect can be employed alone to produce surprising levels of cooling. Buckminster Fuller discovered that geodesic domes would auto cool from this effect if he put small opening in the very top and allow the heated air on the surface of the dome to pull air inside the dome out through open door ways. Later it was discovered that the traditional domed architecture of many desert dwelling peoples also employed this effect. 

If you intentionally draw the air down a small tube configured like a radiator, you may find that you don't need any water at all to produce useful levels of cooling. The compressed air will be warmer than the ambient so it will cool as it passes down the tube. When it reaches the end of the tube, it will decompress and cool even further. 

[fozzy13]

You make a good point about capillary action! I was merely going from the terms I remembered from my chemistry classes.

I'm aware of Charles's Law, however it would only play a miniscule part in this particular setup. This is because the outer window-box is not completely air-tight. Therefore, when air is drawn into the system it is not at a significantly smaller volume than it will be as it moves through the convection shaft.
-Unless you are referring to the air as it expands moving from the unit into the car, in which case you'd be correct!

Geodesic domes are awesome!

Thanks for the read and the comment! : )

[glorybe]

This design will work as an evaporative AC. They are common to cool entire homes in the western desert areas as they work well in arid environments and poorly in humid environments. It is simply evaporation that cause the cooling and not compression of the air. The reason that more common AC units use freon is that cooling and expansion by air is very limited. It would take a lot of energy to compress air and release it through a narrow opening to get limited results. If you look at a capillary tube in a normal AC it can not function with air at all as moisture would freeze and plug the tube. Freon contains no moisture and when AC units are built they are evacuated by deep vacuum before freon is added.

[fozzy13]

Thanks for the comment and insight!! : )

[DeusXMachina]

I love evaporative cooling, and have been trying to build a portable evap chiller myself. I have even thought about using some sort of evap chilling to boost cooling of a car's AC coils or radiator/intercooler.

But I'm not sure a big box full of water is less annoying to put up and take down than a foil sun shade :P Mine takes about 15 seconds if I REALLY have to wrangle with it. And it keeps my car about 15 deg F cooler.

[qorlis]

Sorry that this comment is a bit off topic, but I hope it is welcomed nonetheless.

Folks, I just wanted to make a general comment here about the other comments I've read. I want to applaud all of you for the high quality of your input. I have been reading comments in Instructables for a few years now and I have never been so impressed by them as I have been with the ones here. They are positive and constructive (as stated below) and well worth reading. Bravo to each and all of you!

[--= Excogitate =--]

Very nice! The only thing I foresee being an issue is the ambient humidity. Swamp coolers tend to only work okay in arid climates. Places with high humidity will not support adequate evaporation.

I've also pondered an AC that has no moving parts and isn't too big. My idea's have been based on thermo-acoustic coolers. They use sound to part hot and cool air. They aren't effected by humidity plus relatively simple construction, but efficiency needs work... Oh and there is a magnet based refrigeration cycle (need superconductors though...). Keep it up man! Maybe you can make something and be a gajillionaire.

[fozzy13]

Hi there!
Thermo-acoustics is awesome, though I'm only lightly familiar with it, but as far as I know, there are very few moving parts. I remember seeing a refrigerator that used it in a video at some point. And I'd love to get my hands on superconductors if it were possible cheaply!

Thanks for the read and comment!
Don't worry about bringing up humidity, it may be the one negative of this project.
: )

[--= Excogitate =--]

Geez sorry to bring up humidity; I see a million others did too >_<.

[clay7185]

This idea is a very basic swamp cooler. They used mostly in places like Arizona because the efficiency of the unit drops as humidity increase due to the slowing of evaporation also these units put humidity into the air which is great in Arizona not so good in Iowa where I live.

This unit is a great start it would work really well on a house if you added in an automatic float valve and a fan to speed up the cooling(assuming you live where adding some humidity is ok).

[fozzy13]

Thanks for the comment! A fan at the bottom would be a nice addition, but I wanted to keep it as simple and reliable as possible.

[dkersting]

I'm havind a hard time to visualize this paragraph: "These three principles make the Unit what it is. The sun will shine on (...) adhesion."

Maybe someone could do a small scheme showing the flow of the wather?

[dkersting]

Is there any videos telling more about this project?

[fozzy13]

I have not made any videos about the project. I considered making a few, however I wouldn't really be adding any information that isn't already written here, and since I haven't gotten the kind of response I hoped for upon publishing this, I've been unmotivated to get those explanation videos made.
However, I'm sure there are other videos online explaining the core principles of the Unit.
Thanks so much for the read, the interest, and comment!!

[bobby sissom]

If one was to upscale to a size that would fit a small work shop, my main concern would be the humidity level,would this act simular to say, a swamp cooler,and raise the humidity so high as to make everything in the shop feel damp. It might be interesting enough to try out,I happen to be planning to make a small shop about the size of a one car garage, and just might make the sunny side into an experiment,plus like you said in the winter it could do duty as a heater. I am thinking along the lines of the space already existing between each stud along sunny wall, with vents top and bottom and water filtration shelves about waist high

[fozzy13]

That would be awesome if you upscaled this!! I would certainly love to see it. Humidity is a concern that I thought about during the design stage, but decided not to worry about it due to the scale of the project. The idea I had to get around it was to have two convection channels, or alternating channels. The channels that have water in them would be directed to a sort of heat exchanger, and pass through other channels that would only move air. Thus, the moisture would cool the air, but not make it more humid.
Incorporating this system into the studs on a shop would be awesome, however I think that it would be most effective if the water trough were situated as high as possible. That way the upward-moving air could become cool as close to the downward-moving phase of the convection cycle as possible.
Thanks for the read and the comment!! : )

[bobby sissom]

E#xcellent point ,on the water being a little higher. After i hit send i thought about that, if i cooled the air to soon it would have trouble rising. If i decide to incorperate this idea ,you better believe i will give you props for the original idea and record the results. Might be this time next year before my plans allow me to try.

[fozzy13]

That was along my line of thought as well. I would really love to see this if you do end up building it! Definitely make sure you at least take some pictures!

[jgregory83]

Great thinking! Dont give up on your concept. This is only the first step. I would love to see a temp drop of up to 30^ F. That would put it on par with most AC systems.

[fozzy13]

Thank you! I agree that this is only the first step. I'm sure a more significant drop could be easily implemented with a small solar panel and a fan situated at the bottom.
Thanks for the read and the comment!! : )

[jgregory83]

One more idea would to use copper or galvanized pipe instead of PVC. It would pre heat the water thus causing the water to evap faster. What do you think?

[fozzy13]

That's not a bad idea at all. I chose PVC mostly because it's cheap and easy to work with. Galvanized steel would add a fair amount of weight to a unit, and copper can be pricey. If I were choosing though, I'd go with copper, because it's lighter and more conductive than steel. You should give it a test!