Air conditioner really kills mileage

[Danncomm]

I had the air conditioning fixed in the slug yesterday. About time, temp was in the mid 90's and the humidity was in the low 80% range. Up until I had the ac fixed I was running 90 mpg for 370 miles. I had to do about 80 miles for work and ran the air, by the time I got home it was 82.4 mpg for 450 miles. I knew that ac hurt mileage but the ac combined with my little engine made my poor car even worse as far as pulling power goes, I was driving with little to no wind and would compare it to driving into a 20mpg headwind.

[cfg83]

Danncomm -

Poor little Insight. I fixed my A/C for carpooling and I saw my MPG plunge. I still keep A/C off for accelerating onto freeways. Need every once of power I can get.

CarloSW2

[Danncomm]

I am way too tired tonight to try to figure out the mileage hit the ac caused. Will try to figure out the difference tomorrow. Would figure somewhere in the 30mpg range to cause that kind of mileage hit in the 80 miles driven.

[Old Mechanic]

Last two weeks here I have seen the temp hit 106 with our typically higher humidity.

Sorry folks but no AC is no longer an option for this old man.

I do P&G the AC to try to minimize its impact, but in my Insight it was about a 10 MPG (out of 70) hit. The VX seems to take about a 5-7 hit.

It forces me to change my strategy and just hop on the interstate and not take more time for the back roads and avoid any idling.

When you are in lean burn, even in the 1.5 liter engine on the VX and 5th gear, the load of the AC and just maintaining speed at 62 MPH is about the max lean burn power of that car. The benefit is you spend less time on the road so the overall AC energy use is lower.

When I have to stop, I go max fan and Max AC temp (always on recirculate) to take advantage of otherwise wasted energy.

regards
Mech

[Daox]

Your IMA battery thanks you for AC though. I was just talking with the owner of hybridbatteryrepair.com this weekend and he says heat is the number one killer of packs.

[dcb]

So how do you do "Regenerative" AC?

The simple version is to hook a compressor up to a wheel and blow the cold air over a thermal mass.

There are probably more efficient schemes than that though.

[Laurentiu]

Regenerative AC sounds like a good idea. I always think why do the auto-manuf. never bother to insulate the passenger cabin more properly, glass with lower conductivity that would allow smaller more energy efficient units in the cars. Passive cooling is an interesting idea I read about.
Vehicle cooling systems

L.E. it is appalling to think that the few cubic feet of cabin space in a passenger car which are 10's of times less than the size of 1 room require such vast amounts of Watts to keep it cool..

[Daox]

Originally Posted by Laurentiu

Regenerative AC sounds like a good idea. I always think why do the auto-manuf. never bother to insulate the passenger more properly, glass with lower conductivity that would allow smaller more energy efficient units in the cars.

Someone at drive green expo asked a Ford rep in a meeting about this. He said they have no plans to insulate the cabin as far as he knows.

[JellyBeanDriver]

Originally Posted by Laurentiu

glass with lower conductivity that would allow smaller more energy efficient units in the cars.

More like coatings to reflect infrared energy instead of letting it in to bake the interior.

[JeepNmpg2]

Originally Posted by Daox

Someone at drive green expo asked a Ford rep in a meeting about this. He said they have no plans to insulate the cabin as far as he knows.

Of coarse not, that would make sense wouldn't it? For my jeep, if I cut the ac on it is a 1-1.5 mpg detriment, which doesn't seem like much until you realize that it is about 4-6% of my overall. So it would seem that ac's in general draw up to 10% of your engine power. At least mine on recirculate/max and on low, while on the freeway the compressor only comes on for 2 or so seconds then stays off for almost 10.