Slightly open window?

[ksa8907]

With my dodge intrepid I didn't have a/c until the last year I owned it. It was standard MO in the summer to crack all 4 windows 1" or less with the fan on. The cabin air will get sucked out which will assist the fan in providing more air into the cabin.

[Ecky]

I don't even run the fan when I have my windows cracked; the suction pulls plenty of air through the vents.

Check this:

Fuel Efficiency: AC On Vs. Windows Down - Business Insider

The researchers used a wind tunnel and laps on a track to test a sedan and an SUV at speeds of 31 mph, 50 mph, and 68 mph, in 86 degree F weather.

[stefanv]

Originally Posted by redpoint5

Most vehicles have fairly high electrical draw just running the fans, perhaps around 200 W on high (measured the TSX at 220W).

I'm going to have to measure mine. It can't be anywhere near 200W though since the entire HVAC system, including the rear window defogger, is on a single 15A fuse, so at 14.5V, that would be 217W total (fan and defogger both running) if the system was designed to run right up to the rating of the fuse (unlikely).

I'd be surprised if it was much more than 50W in my car.

[cRiPpLe_rOoStEr]

Originally Posted by stefanv

I'm going to have to measure mine. It can't be anywhere near 200W though since the entire HVAC system, including the rear window defogger, is on a single 15A fuse, so at 14.5V, that would be 217W total (fan and defogger both running) if the system was designed to run right up to the rating of the fuse (unlikely).

Considering that it's fed by the battery with 12V DC, the entire system shouldn't operate with more than 180W.

[stefanv]

Originally Posted by cRiPpLe_rOoStEr

Considering that it's fed by the battery with 12V DC, the entire system shouldn't operate with more than 180W.

Yes, when the car's not running, it's 12V. When it is running, the alternator is keeping the voltage up around 14.5V, hence my 217W figure.

[teoman]

I have been pondering about this. I try to use the windows as much as possible. But I really enjoy the AC. (I am half Finnish living in Turkey). I only use a jacket a couple of times a year (besides a motorbike jacket). Nowadays urban areas are so dense that i have a tshirt on even when it snowing. Time spent outside is always less than ten minutes and my thermal inertia can handle that (i do have a little bit of (20lbs) excess).

AC on full blast is rarely enough. It can be humid over here and i get soggy really fast.

There must be ways to increase AC efficiency.

I shall install a water misting system to the AC condenser when i get the chance.

I would like to experiment with AC systems. Increase the amount of refigerant in a reservoir, so regenerative braking can be used to refill it. That way the cooling can be virtually free. Unfortunately auto work here costs an arm amd a leg. A transmission swap or engine swap is unheard of. Some one doing it diy does not exist! There mayyy be that one guy in the whole country who has done it DIY.

[teoman]

Ps: on my car there is an ac disable button that cuts off the power to the compressor clutch.

I use it a lot, enable the compressor only when decelerating. Seemed to work ok untill the ac quit because of a burned clutch.

[freebeard]

There must be ways to increase AC efficiency.

Paint the roof white.

[teoman]

I will install reflective foil once my transportation situation stabilises.

[aerohead]

Originally Posted by teoman

I have been pondering about this. I try to use the windows as much as possible. But I really enjoy the AC. (I am half Finnish living in Turkey). I only use a jacket a couple of times a year (besides a motorbike jacket). Nowadays urban areas are so dense that i have a tshirt on even when it snowing. Time spent outside is always less than ten minutes and my thermal inertia can handle that (i do have a little bit of (20lbs) excess).

AC on full blast is rarely enough. It can be humid over here and i get soggy really fast.

There must be ways to increase AC efficiency.

I shall install a water misting system to the AC condenser when i get the chance.

I would like to experiment with AC systems. Increase the amount of refigerant in a reservoir, so regenerative braking can be used to refill it. That way the cooling can be virtually free. Unfortunately auto work here costs an arm amd a leg. A transmission swap or engine swap is unheard of. Some one doing it diy does not exist! There mayyy be that one guy in the whole country who has done it DIY.

If you have ground level ozone,there is a risk that misting will create nitric acid which could chemically attack the condenser coil.