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Hi, relatively new to hypermiling, and just barely breaking/hitting 40mpg in a saturn ion.

I don't use a scan gauge and I don't have a fuel consumption display, so i'm trying to find out about how much does FE take a hit at steady state cruising on average with running the air conditioner at its lowest setting on cabin recirc... the reason being Houston isn't exactly the best place to run in the summer with windows shut or barely cracked with air on vent only. I generally run with only the windows cracked, but sometimes I try just windows shut and on vent and cycle the A/C button on and off to get a littel bit of cooling on the hotter days.

Welcome to CleanMPG!

I live 250 miles north of you on I45/US75 in Dallas - Dan is in Houston.

A/C in a necesssary evil, but I keep it to a minimum by parking under the shade, opening the car up a minute to get hot air out. My hierachy of A/C use:

mildy warm: fan only
warmer: A/C coasting to a stop
yet warmer: A/C on downhills, cruising
hottest: A/C all the time (over 100F)What kind of car do you drive? Reason I ask is if it's a 96 or later, it can probably use ScanGage.

Its a 2004 saturn ion (non hybrid) with a 5 speed manual... it can probably use a scan gauge, but I havent' felt like spending the money on one yet =)

Its a 2004 saturn ion (non hybrid) with a 5 speed manual... it can probably use a scan gauge, but I havent' felt like spending the money on one yet =)

All I can say is ScanGage or anything else that give you the instant mpg makes it a lot easier to know what works and what does not. Plus with ScanGage, you can turn that loose gas cap code off. :)

I registered a consistent 15% increase in fuel consumption driving my 5-speed Accord on the open highway. I would think an Ion to be in the same ballpark.

Hi, relatively new to hypermiling, and just barely breaking/hitting 40mpg in a saturn ion.

I don't use a scan gauge and I don't have a fuel consumption display, so i'm trying to find out about how much does FE take a hit at steady state cruising on average with running the air conditioner at its lowest setting on cabin recirc... the reason being Houston isn't exactly the best place to run in the summer with windows shut or barely cracked with air on vent only. I generally run with only the windows cracked, but sometimes I try just windows shut and on vent and cycle the A/C button on and off to get a littel bit of cooling on the hotter days.
Welcome... Sorry I missed the post. I'm up here in Cy-Fair and and run the AC unconditionally for the last 2 weeks. It hit me as about a 5-7% decrease in FE. I just have to live with it till December.

Hope you can make it to the Houston Fuel Efficiency / Hybrid meetup (http://www.cleanmpg.com/forums/showthread.php?t=5099)

11011011

OK. I'm guessing that P&G'ing your a/c will net higher FE just as P&G'ing the ICE. So, how about putting a/c on high and recirc - and pointing the vents away from skin to avoid severe pain - then cycling the a/c and fans on and off manually as needed.

Slightly off topic, but your post made me think of this:
http://blogs.edmunds.com/strategies/224

I try to be energy conscious, but I love air conditioning.

We just got over a heat wave here in new england (a heat wave is technically defined as 3 more more days of >90 avg daytime weather).

Anyway, I'm too stubborn to use my AC. First and foremost, when I run the car with AC on, I lose too much power, plus the half of my driving is in stop and go traffic. Somehow I'm able to maintain i high level of fuel efficiency in spite of that, but I'm sure that AC + crawling commute = sub-hypermiling FE.

I just fill a Nalgene bottle with water, open my windows, and creep along with everyone else.

TO that end, one of the biggest mistakes I made when buying my car (and I really didn't have anyone to tell me otherwise) was getting it with black exterior and black interior. So for the whole summer I suffer.

Of course it's nice when the weather is in the teens or below, and you get into a car that's in the 20s. But those days number far fewer than the summer days.

Well anyway, I finally broke down and ordered a scangauge ... I figure the fuel I save over time will more than make up for it.

This will answer my question with real evidence for my car, along with helping me find the most efficient speed for steady state cruising and how much using the windows affects drag and fuel economy =)

I don't own a scan gauge either, but I have been looking at one for quite a while, and I will probably get one soon. With that being said, here's an air conditioning question. Does it make much of a difference if the automatic climate control (2004 accord v6) is set to something cool enough to feel comfortable (maybe 76 degrees) as opposed to "arctic air mass" (closer to 60 degrees). My thought would be that a warmer setting would mean that the AC compressor was working that much less.. But, I'm not sure if the compressor works like that (on off cycles.) .

Here would be a great time to have a scan tool.

I generally find that more AC consumes more gas, but my compressor is electric (Prius), so there may not be a direct comparison.

On my car, I set it to the warmest auto setting that doesn't turn on the heat. For Texas, most of the time that means setting the AC to about 85. If we get a cold front and the temps drop below 80, I usually set the AC to ambient. On my car if the outside temp is cooler than the inside temp it interprets that as a heat request.

My main reason for using the "AUTO/AC" setting in my car is simply convince. I have an AC on-off button on my steering wheel and it only does the on-off for the "AUTO/AC". This lets me kill the AC when I need power and turn it back on when I'm not drawing much power.

My wife used to call her AC button on her 1980 Sentra her "Turbo" button. Idea was she'd hit it (turn off AC) when she needed to climb a hill or something. I usually just down shifted, but her method was much more fuel efficient. I've adopted the use of the "Turbo" button in my Prius. When I need to do a high intensity pulse, I hit turbo. One exception is stealth-warp. Stealth-Warp seems to draw a lot of power, so the only way to hit it with out a 6-bar-pack is to throw on the turbo button.

11011011

I'm very impressed by the electric compressor portion of the Prius. My dad has one (in the northwest) and I really enjoy driving it when I visit.

You mention setting the AC to the the warmest that doesn't interpret it as a "heat request".. I'm not sure I'm ready to go that far (it's been in the 90's with humidity that won't quit here in Florida)

Anyways, here's another AC related question... So, when driving in traffic (in a non-hybrid car) and approaching a red light or stop sign or something like that, does it make sense to anyone else to turn on the air conditioning (assuming it was not being used while cruising) for an added dose of "engine braking" ie turn some of the kinetic energy in the car's motion into energy to operate the AC compressor instead of turning it all into thermal energy at the brakes (or drivetrain / aerodynamic losses through coasting to a stop)

For what it's worth, I'm still familiarizing myself with all the nuances of different hypermilling techniques.. Right now, I'm using a small degree of forced auto stop and using cruise control at a reasonable speed (closer to the max FE point on the curve than 65mph anyways..)

Hi Rleech:

___Great to see yet another Accord driver over here! These things are pretty hot in their own right. With regard to Fuel Economy that is ;)

___Oh boy did this experiment cost me (60.6 down to 57.2 over 13 miles but I got her back to 57.8 pulling into the drive …) but I saw your post this afternoon and thought the following might help? To answer your questions wrt a 7th Gen Accord, what I was seeing in 81 – 82 degree temps with A/C set to Auto and 58 degrees F was .4 GPH with an occasional blip down to .3. With A/C set to Auto and 78 degrees, I was seeing similar with more occasional blips down to .3 gph. To grab more resolution, I swapped the liquid measurement to metric. The 58 degrees F and Auto setting locked in a solid 1.4L/Hour during a NICE-On while the 78 degrees F and Auto setting would cycle like clock work between 1.4L/hour and 1.0L/hour. A/C was on for ~ 20 seconds and then off for ~ 8 seconds. A straight NICE-On without A/C was consuming 1.0L/hour. Now this is with the I-4 so your V6 will be consuming more fuel during idle but the hit with A/C should be a touch less then the 40% hit I was seeing (at idle) with the I4.

___I hope this helped and thanks for the A/C although I wish it would have been 95 while I performed this 20 plus minute experiment vs. the low 80’s which I now call comfortable :)

___Good Luck

___Wayne

I got a chance to play with the A/c in the Civic yesterday. Steady 60 mph going down the road was a instant hit of 4 mpg. Turn the A/C on and SG dropped right then and there. 4mpg gone.

Ive done this with the Accord also. Results were the same. Instant 4 mpg drop in mpg.

We also found out that putting the sun roof in tilt was a instant 3 mpg hit. With or without A/C.

psy

PS,,, I really am starting to dislike summer. :(

I don't know how relevant this is to other cars out there but mine does not seem to change the compressor cycles that much for different settings. When you want it warmer it just mixes in engine heat. For this reason, if I just have to cool off I manually cycle using the "turbo button" with the temp set at maximum cooling (:) I like that name as that is exactly what I used it for in the '95 Elantra -- couldn't get going from a stop with the AC on!!!). Before my concerted effort with new techniques I'd just turn it on during downhill stretches and when coasting up to a light during NICE ON. I still do this but now I also will flip it on during the glide portion of a NICE ON P&G effort. I still see a hit but I can exercise more control over it by adjusting the duration of both the AC runtime and the glide.

That said, I've only used a max of 2 AC "pulses" during any of my drives so far this summer -- ignoring the times the wife was in the car, of course. ;) With that exclusion I've only used the AC for 3 "pulses."

I was fighting using the A/C on my drive from work as much as I could. I would bring a nice cold drink with me on my way home from work but once the temps started hitting above 105°F I couldn't last any longer. I think yesterday in my area where I work the temp was 118°F :eek: at around 2pm on my way home! Today isn't going to be any better with a high of 113°F.

I'm with you psyshack, I really hate summer.

A couple of dittos: Sometimes it's just good to know "you're not the only one". I too, for the longest time, have referred to the A/C button as the "Turbo Boost" button (with the added embarrassment of referring to Knight Rider (http://www.imdb.com/title/tt0083437/). This is funny, I was just telling my wife, with all those retro movies like Dukes of Hazzard, we can expect a Knight Rider movie - turns out they are indeed working on one. I wonder how that will turn out... "KITT, slow down, we'll never make Elite Hypermiler this way.... and show me our fuel economy for the last three days!").

I also feel a big hit to FE when turning it on, so "pulsing" the A/C has just made sense to me, although other people don't always see it that way - "just leave it on at a little higher temperature already!". Easy for them to say; YOU're the one fretting all trip long about the extra gas being consumed :). It's not like it's working any LESS when I turn up the temperature... Plus the fan regulator has lost some of its functionality - it's either OFF or on HIGH :) - so "pulsing" just comes naturally.

Finally, I'm also in the "hate summer" camp. Despite a warm spring I'm happy to say I haven't had to use the A/C much yet. By the time I finally get to go home I can handle it with just the window down. During the day it has to be on though... Can't stand the heat... Hence my user name.

Just to give you some perspective, I've been looking at A/C effects on my mileage.

So I've set my A/C to AUTO at around 80 ºF and run it on all commutes.

My morning commute has about a one hour soak with the EBH and with the Garage temp at about 90 ºF. The outside air temp (OAT) is usually 85 ºF.

My evening commute has no soak on the EBH with an engine that has cooled for 9 hours. The parking garage temp is about 100 ºF. The OAT is usually about 95 ºF.

The difference in consumption on the morning and evening commutes is 5-6 oz of gas. The commute is 14-15mi and 35-40min.

So the 10 ºF delta in OAT from the morning to evening commute translate to 9-10 oz / hr. So based on my high scores, the AC probably consumes 10 oz/hr in the morning and 20 oz/hr in the evening.

So once August hits with it's triple digit mornings, I'm gonna have a tough time holding a PoE above 100% since my AC will likely burn 15-20 oz a trip just to hold cabin temperatures at 80.

Edit:
Comes out to 1 oz/hr per ºF over 75 ºF. So
at 80, AC = 5 oz/hr
at 85, AC = 10oz/hr
at 90, AC = 15oz/hr
at 95, AC = 20oz/hr

11011011

I also "pulse" the compressor button, and only allow it to be on or off at certain times.

My terrain is very hilly, and anytime I'm on a incline it's off.
Another way of saying it, I'm never accelerating or climbing hills with the added load of AC.
I try and take advantage of the car's weight by running AC while going downhill. It's kept my AC tax to minimum. It has made a big difference in my case.
My car isn't a rolling refrigerator, but it can remain tolerable even in the hot, humid Georgia summers.
I doubt it would really matter uphill vs downhill with an electric AC, such as Prius.

I haven't done any study regarding setting compressor cycle duty of a warmer temp setting vs full cold. But I do know that when I turn the dial to warmer, the ducts allow heated air in the mix- which I consider counter productive. It would be interesting to see an analysis of this.

One can always go extreme as I have in past summers- that is bring a ice bucket and cloth.

-Steve

It's hot in FL. Just blisteringly hot. I'll pulse the AC over the course of my 20 minute commute home, probably spending a good 12 minutes with it on. Any FAS and the AC is off, obviously. I understand that I am paying for a creature comfort, and at the same time, I'm trying to modulate my usage so that it's optimal. No AC load on acceleration, uphill, or any idling.

And no AC in the morning makes up for it a bit. :)

Something that I've found that helps is to close all other vents except for the 2 on either side of the steering wheel. That way I can have it on the lowest setting and it still blows out pretty hard.

IIRC, fan/blower setting will not affect how much your compressor runs. Then again . . . anyone have any more knowledge?

A... Plus the fan regulator has lost some of its functionality - it's either OFF or on HIGH :) - so "pulsing" just comes naturally.


I just had mine repaired. It was a $25 part. I highly recommend it. Mine was only working on 3 and 4, and now I have 1 and 2 as well.

Where I post from in Canada, if we didn't do an aftermarket interior insulation the heater in some vehicles often wouldn't keep up to minus 50F temperatures. The upside during about 2 or 3 months of +80 and 90 summer tempuratures here is that once a well insulated vehicle is initially cooled down with AC it stays colder for a lot longer, and a second is that as the AC seldom kicks in it also lasts longer.

One way to get it done is to take the car to an autobody shop and and several hundred's later you may or may not have a well insulated vehicle :rolleyes: , another is to research the materials needed such as closed cell foams, low-E film for windows, hvac aluminum foil and tape, butyl rubber sheeting, 3m thinsulate, etc, get an owners service manual which details the steps needed to pull and replace the body panels, roof liner, seats, carpet, etc and dedicate an afternoon to the project. An added benefit is that you get to address any other problems such as rust spots starting in the door panels or along the window sills, that are not usually seen.

A good compromise might be to go to a local body shop or backyard mechanic, get them to pull the interior, install the insulation products yourself and have the body guy put the panels back in for you. Once you get the car well insulated you can almost keep it cold by leaving the lid off of a cooler with a few frozen ice packs. :)

As an aside question do any know the aproximate amp draw of electric AC compressors. Thanks.

As an aside question do any know the aproximate amp draw of electric AC compressors. Thanks.

On the Civic Hybrid the AC compressor is actually a hybrid scroll compressor. If I recall correctly, the electric half of the compressor can draw up to 10 amps. Usually it is throttled to less depending on the automatic climate control settings.


MSantos

It's hot in FL. Just blisteringly hot. I'll pulse the AC over the course of my 20 minute commute home, probably spending a good 12 minutes with it on. Any FAS and the AC is off, obviously. I understand that I am paying for a creature comfort, and at the same time, I'm trying to modulate my usage so that it's optimal. No AC load on acceleration, uphill, or any idling.

And no AC in the morning makes up for it a bit. :)

Sounds about how I use it. I don't know if E. Texas gets as hot as Florida, but coming from California to Texas, it gets SO hot here, I can't stand it, but I do try to cycle the a/c on and off. Otherwise, I went years in a car without a/c, so it's become second nature to open windows, and I prefer the feel of fresh air to that of a/c. Of course, if I have passengers, I'm gladly willing to take the FE hit and use A/C so I don't have to listen to their whining. ;)

I imagine E. Texas and FL have similar heat - we've got the wet, heavy humidity and ya'll have the arid, hot heat. Either one will make you sweat like a horse. :P

My old Taurus didn't have AC and I also rolled down the windows for any sort of cooling. Once my tint sets in on the Mazda and weather cools off, I'll run the AC sparingly, only to keep the system fresh.

On every car I've ever owned, the compressor is always on if the A/C is on. Cars with automatic climate control (which I've never had) probably cycle it on and off, and it would be pretty easy to tell. I've always used the A/C switch as a Turbo-boost button too, and almost always turn it off for acceleration or climbs.

On my Subaru, the ScanGauge indicates 0.2 gph 90% of the time while idling, with occasional blips to 0.3 gph. With the A/C on it indicates 0.4 gph most of the time with fairly frequent blips to 0.5 gph. On the highway the mileage penalty appears to be 2-3 mpg, but I need to do some more testing to be sure.

I've run the A/C a fair amount on this tank and it has definitely cost me. Will just barely hit 30, I think. We hit 103F last Tuesday and have had a lot of days in the 90s. I try to avoid it as much as possible while driving alone, but my toddler gets really hot in his plastic shelled carrier in the back seat. Without A/C he ends up a sweaty mess no matter how much cold air I aim back his way.

I imagine E. Texas and FL have similar heat - we've got the wet, heavy humidity and ya'll have the arid, hot heat. Either one will make you sweat like a horse. :P

No trust me...only West Texas gets the dry heat. It's humid here, as the gulf moisture takes a direct march through us here in E. Texas. Still not as bad as FL I imagine, though.

Here's a comparison. The two look pretty darn similar to me, with Florida slightly higher temperature.
Orlando, FL (http://www.srh.noaa.gov/forecast/MapClick.php?CityName=Orlando&state=FL&site=MLB&FcstType=graphical)
Tyler, TX (http://www.srh.noaa.gov/forecast/MapClick.php?CityName=Tyler&state=TX&site=SHV&FcstType=graphical)

No trust me...only West Texas gets the dry heat. It's humid here, as the gulf moisture takes a direct march through us here in E. Texas. Still not as bad as FL I imagine, though.

I wouldn't doubt it - it's hot in both states. I like Wayne's solution - need to get one of those cold-water suits to wear for driving. For now, it'll be AC P&G. ;)

I just had [my fan regulator] repaired. It was a $25 part. I highly recommend it. Mine was only working on 3 and 4, and now I have 1 and 2 as well.

Yeah, the parts are always cheap, it's the labor that kills you :). Actually, I did ask my mechanic if he could fix that a long time ago... Unfortunately, the good man is cheap and honest and as such in high demand - meaning he's always swamped and just about everything else has a higher priority than my fan regulator :(. (Can't really complain though; if something is seriously wrong, like brakes that are about to go out, he'll drop everything and fix that.)
Plus, neither of us had thought my car would still be on the road today :).

We get dry heat in NM, but that also is why we don't have that many trees. Parking in the shade is at a premium. Even where I work in the summer and can trust people and keep my car open all day I could still probably could something (rib roast maybe?) if I didn't have the air on. I have always tried to use the minimum of air. I like the idea of turning the other vents off. Might try this if it is possible.

I had my car painted white to get a bit lower temps. I didn't do the tinted windows. I think that does make a difference. I have found that the shades on the windshield help but not that much if you park all day in the sun.


--des

I ran some AC effect on FE tests last weekend for my HCH2 - posted under FILES at left. Not suprisingly, AC kills FE, although the impact was higher at 55mph vs 70mph.

Well, here's something I don't get. I glanced through Consumer Reports' New Car Buying Guide the other day, and in their tests, running the A/C only lowered the FE by 1 mpg! (The effect of driving with the windows open at 65 mph couldn't even be measured.)

What vehicle did they use for testing!? Certainly not mine! :)

Well, here's something I don't get. I glanced through Consumer Reports' New Car Buying Guide the other day, and in their tests, running the A/C only lowered the FE by 1 mpg! (The effect of driving with the windows open at 65 mph couldn't even be measured.)

What vehicle did they use for testing!? Certainly not mine! :)

You fail to give the common driver his/her due for ability to lower FE with "normal" driving!!

I know what you mean, though. I drive without AC and the windows all rolled up even at low speeds. I just have the vent on with the fan set at level II (of IV) with all outlets directed at my face. I can definitely tell the difference in glide distance at moderate speed if I have the windows rolled even part way down.

I drive without AC and the windows all rolled up even at low speeds. I just have the vent on with the fan set at level II (of IV) with all outlets directed at my face.

I drive the same way, and so far it works real well. But it hasn't been more than high '80s here yet.

I don't know how you guys handle that... My commute is fine, but during the day, or I should say as soon as the sun starts beating down on you, high 80s? NEED AIR!!!

I drive the same way, and so far it works real well. But it hasn't been more than high '80s here yet.

I've done it up into the high 90's before and do pretty well for about the first 20-25 minutes. Then I need a one or two pulses of AC to get me through the next 20 on the way home.

I don't know how you guys handle that... My commute is fine, but during the day, or I should say as soon as the sun starts beating down on you, high 80s? NEED AIR!!!

:D I grew up in muggy SC driving a '70 VW Bug with pop out rear windows, no AC, no fan, and black vinyl interior. Nothing but whatever breeze you could generate by moving. Temps in the summer were usually low to mid 90's most of the time with August showing low 100s -- usually one week with nothing but 100+ every day. With no alternative you toughen up a bit. ;)

Seriously though, push yourself a bit at a time and I'll bet you discover you can handle more than you thought. Don't pass out though. That's seriously bad for FE. ;)

You don't understand - without A/C I will require Excedrin, a shower and a clean set of clothes at my destination (and that's assuming I brought enough water to stay hydrated). It's not that I CAN'T do it... If I were to engage in, let's say, an MPG Challenge of any kind :D, I might try that passing out thing you mentioned before turning it on! But in regular driving, it's just not worth saving a dollar - if that much. And when dressed up, not using the A/C just isn't an option.

Can't wait till summer is over!

I can certainly understand the need to keep your clothing in decent shape. Yesterday the back of my shirt was completely soaked. For me it is merely uncomfortable because I'm on my way home and don't need to go elsewhere. Once I'm there I just strip down to shorts and sit in front of a fan for a few minutes to dry off.

I don't get that extreme when I have to be presentable, but that isn't usually an issue after my afternoon/evening drive. :)

I can certainly understand the need to keep your clothing in decent shape.
But you have no sympathy for the headaches :).
Like I said, I'm fine without A/C on my commute; it's the other 10-12 hours behind the wheel...

It was about 90 degrees the other night and I had to take an hour long drive. I decided that it's dark and I'm driving on the highway so I took off my shirt soon after I started going. It was actually relatively comfortable with A/C off and the fan on low.

But you have no sympathy for the headaches :).
Like I said, I'm fine without A/C on my commute; it's the other 10-12 hours behind the wheel...

Sorry -- missed that one! I don't generally get headaches -- and the ones I do get aren't much more than a dull ache. Hey, do what suits you but I can tell you from experience that the savings without AC on are quite significant and are immediate. :)

If you can't do it, you can't do it.

It was about 90 degrees the other night and I had to take an hour long drive. I decided that it's dark and I'm driving on the highway so I took off my shirt soon after I started going. It was actually relatively comfortable with A/C off and the fan on low.

Having your shirt off does make a BIG difference. Now that you mention it, I'm going to do that more often.

I believe I'll be keeping my shirt on, otherwise I might get arrested for indecent exposure-- but nice idea boys. :-)

For those of us who do want to keep our heads clear and arrive in one piece there are options to not using a/c at all. I find people very indiscriminate about when they use their a/c and how high up it is. Went out last night with someone and he had the a/c at full tilt even though it was 8 PM or so and it was a lot cooler outside. I think about how high I want the a/c and whether I will use it or not. That way I am only using the amt. (maybe somewhat less) than I would want in a perfect situation.

The a/c is turned off when I get in the car, that way I set it each time to how much and how high I really want it. I do the same thing in my house, and so the air is not always blaring.

I think a thermometer would be a good idea but I am scared to see just how hot the car gets after sitting all day in the sun (no other option).

--des

Here's a fairly good solution to cooling needs from an aircraft application,
the interesting thing about these is they reduce cabin humidity as well.;

http://www.sportys.com/acb/showdetl.cfm?&Product_ID=10784&DID=19

...and another cold water/ice type cooler for various applications;

http://www.swampy.net/index.html

...some info on a similar homebuilt unit for cost savings.

http://www.instructables.com/id/EHNCAI7F54HJ6C4/

These are interesting ideas for someone with $500 lying around or who is good at diy (and who could hold a bucket of ice around with it out it thawing all day.

BTW, there is a personal a/c (that it is air conditions you).

There is the high tech gadget (didn't get such a great rating).
http://www.amazon.com/Personal-Cooling-System-3-0-SI758CB2/dp/B0009R3JMU

OTOH, I think you can get a cooler vest for $40 or a neck wrap for $5 or a hat at a dollar store. Might do better.

All these cool by evaporative cooling-- won't do much in high humidity.
If evaporative cooling won't work the alternatives are not cheap. I have salt water tanks as a hobby and one of the more expensive aspects is people trying to cool their tanks. Since they can't use copper (being deadly to marine organisms) you're stuck with titanium.


--des

Here's a fairly good solution to cooling needs from an aircraft application,
the interesting thing about these is they reduce cabin humidity as well.;

http://www.sportys.com/acb/showdetl.cfm?&Product_ID=10784&DID=19

...and another cold water/ice type cooler for various applications;

http://www.swampy.net/index.html

...some info on a similar homebuilt unit for cost savings.

http://www.instructables.com/id/EHNCAI7F54HJ6C4/

These are interesting ideas for someone with $500 lying around or who is good at diy (and who could hold a bucket of ice around with it out it thawing all day.

Flyboys often go to great lengths to make efficient decisions...maybe we could gain some insight from people who's lives often depend on efficiency.

I would do it in a heart beat if I could keep a thing of ice in cold all day without carrying it inside with me, AND I could build anythign with my hands.

--des

Flyboys often go to great lengths to make efficient decisions...maybe we could gain some insight from people who's lives often depend on efficiency.

I would do it in a heart beat if I could keep a thing of ice in cold all day without carrying it inside with me, AND I could build anythign with my hands. --des


Hi Des,

you might want to look at a Coleman Stirling freezer which draws about 48 watts, I've seen these at Costco for under $400. It could be installed in the trunk and ducted to circulate cabin air or put between the front seats and vented to the outside as they kick out some heat when running. A more expensive solution that I've seen 4x4er's in Australia use is to run similar freezers on a separate battery/emergency power supply unit kept charged with a solar panel. If installed in the front a single 12v computer fan on top of the freezer to circulate air through frozen gel refrigerant bags should work as an effective AC unit.

http://www.coleman.com/coleman/colemancom/detail.asp?product_id=5726-750

Thanks, I think it is a little over budget. :-)
I think the little project involved less than $100 of parts.


--des

Hi Des,

you might want to look at a Coleman Stirling freezer which draws about 48 watts, I've seen these at Costco for under $400. It could be installed in the trunk and ducted to circulate cabin air or put between the front seats and vented to the outside as they kick out some heat when running. A more expensive solution that I've seen 4x4er's in Australia use is to run similar freezers on a separate battery/emergency power supply unit kept charged with a solar panel. If installed in the front a single 12v computer fan on top of the freezer to circulate air through frozen gel refrigerant bags should work as an effective AC unit.

http://www.coleman.com/coleman/colemancom/detail.asp?product_id=5726-750

Rather than fooling around with coolers, ice and storage, etc, a more compact solution for a pure AC application might be to get a 12v 'Free Piston Stirling Cooler' from the company supplying to Coleman, or scavenge one from a Coleman freezer, installing a convective fan and condensation drain line for the cooling side, and a fan or ducting to dump waste heat from the unit outside the vehicle. For budget minded there should be Coleman Stirling freezers on the used market. This unit might not be effective to initially cool down a vehicle but it may be enough to maintain temperature without further use of the AC.

http://www.globalcooling.com/documents/M100PublicityPack.pdf

http://www.globalcooling.com/products.html

Well, here's something I don't get. I glanced through Consumer Reports' New Car Buying Guide the other day, and in their tests, running the A/C only lowered the FE by 1 mpg! (The effect of driving with the windows open at 65 mph couldn't even be measured.)

What vehicle did they use for testing!? Certainly not mine! :)

It was probably a comparison between running with the AC and running with windows wide open... but I seem to get better MPG even with windows open than running AC (of course, I don't go 65 either.... and during the one stretch that I do the windows are either partially open or I'll sweat it out since its a short run if i'm in the mood)