15 miles isn't bad. I commute about 9 miles to work every day. I have the 4WD FEH and I average about 30 MPG. If I go just a little further I probably get about 32-34. I haven't done any of the air pressure tricks for the tires, and I drive pretty "normal." As for the A/C. When its on its pretty darn cold. I have to turn it down. At intersections I find the recirculate mode is plenty unless I'm sitting for 4 or 5 minutes or its extremely hot outside. If it gets that way I just reach over and pop on the max A/C for a minute.

Its completely under my control and I find I rarely have to pop on that max A/C.

 

It is true that all the energy used comes from the ICE, however, I think that an electric A/C could actually be more efficient (as opposed to ICE-driven Mac A/C) in terms of MPG.

The battery gets charged while the ICE is running and by braking. Now if the A/C could stay on while the ICE shuts off when it isn't needed - eliminating the need to run the ICE solely for A/C (very wasteful...gas burned for no miles gained) - this shift would still allow higher overall efficiency by using the stored energy in a situation where the ICE isn't needed.

I think it's similar to driving in EV mode, shifting traction to electric at slow speeds (where the ICE is less efficient) and leaving the ICE off so as not to waste gas, is a better overall option.

It's the shift/blend of electric and ICE power that makes hybrids what they are... that's why a hybrid can achieve much higher MPG compared to a conventional vehicle, even though both vehicles derive all their power from the ICE.

Of course, it depends on the type of driving you do and your A/C usage. Electric A/C might be more fuel-efficient for some and worse for others.

 

I'd be real interested to know what size the electric motor is that drives the a/c compressor in the Camry. Any experts out there know what kind of horsepower it takes to run a car a/c? I know it is a significant amount since you can feel the difference when the compressor kicks in on any car (you can see it in the mpg too). What about Camry owners - what kind of difference do you get in your EV mode when you are using a/c versus when you are not?

 

The TCH has an ECO mode for the A/C that somehow avoids a big hit on the mpg. Monday I drove over an hour (about 30 miles in 105 to 110 heat in freeway rush hour traffic, very humid too...) with the A/C set to 77, ECO and recirc on and did not notice any drop in my tank mpg. I park in a parking structure so the A/C doesn't have to work so hard to keep it cool.

If the car is parked in the shade, I honestly think the mpg hit is under 1mpg for the A/C running in ECO mode. Now if I park in the sun, I notice a big hit - a good 2 or 3mpg drop is my estimate. It takes a lot of energy to remove all that absorbed solar heat, and while the A/C blows cold, it takes time to cool down.

I'm curious too about the compressor sizing and power managment. I can't tell if it cycles like a belt driven compressor or just 'throttles back' and uses less power to regulate the temperature.

 

Nash, since you have both types of vehicles - which a/c system do you prefer? Which seems to effect gas mileage the least? Do you see any drawbacks to one over the other?

Wat about impact on performance?

Thanks

 

I prefer the TCH electric A/C, mostly due to the constant cooling in EV mode. Both cool down, and perform about the same. Our FEH drops from 30mpg to about 28mpg when running the A/C all the time. I don't need A/C in the morning with the TCH, so I'm not sure about the mpg hit, but my feeling for it is they both have about a 2mpg hit if you park in the sun.

I suspect the belt driven A/C compressor on the FEH will not last as long as the electric A/C TCH compressor. The belt driven compressor has both a clutch and shaft seal that wear out. The TCH compressor appears to be a sealed unit, with no shaft seal or clutch to wear out.

Edit: I have FormulaOne Pinnacle 35% tint all the way around (not the windshield!) as the first thing I noticed was how much heat came in the TCH rear window. The tinting dramatically reduces the heat and improves the A/C comfort.

 

That's a good point.

With a ICE driven compressor, you have that electromechanical clutch to deal with. Plus, an ICE driven compressor has to be "over designed" with not under compressing the FREON at low ICE RPM's, while not over compressing the FREON at high ICE RPM's.

The electric driven compressor doesn't have the clutch, and runs at a fixed, known, RPM. A much more simple and, I would venture a guess, more efficient design.

 

Since I'm not unhappy with the way it works in the Escape, I won't quite say I wish it had electric a/c but I am starting to be a believer that it may be better.

We are allowed to change our mind around here, right?

 

So on the TCH, is the A/C for the EV battery run off the same electric compressor as the cabin air? I assume it would be.

One appeal of the electric A/C is the ability to run the air without the ICE when the car is parked. Many times at work during lunch hour I see people sitting in their vehicles, engine running, A/C on, reading, napping, or talking on the cell phone. That's something I personally wouldn't do, but with electric A/C it seems somehow less wasteful than idling the engine for an hour. I wonder how long the electric A/C can run on a full battery?

Don

 

I need to investigate the TCH battery life when running theA/C only. We've only had our car 2 weeks. The ICE turns on and off frequently as needed. It is fairly quiet. You can be sitting at idle (with the radio on) and not really know what you are running on unless you look at the monitor.