Actually it's quite the opposite -- if the a/c runs on electricity, we have to contend with conversion losses. Escape saves on this conversion loss by using the gas engine to run it. It is actually more efficient to run the engine than to convert kinetic energy to electric then back to kinetic to run the a/c compressor.

That might be true, but some people think that an engine driven compressor has to be oversized to provide good cooling at low engine rpm. An electricly powered compressor can be run at a single speed as needed, and can be built to an optimal size. Also, electric compressors don't have the frictional loss of a pulley and clutch system that keeps on spinning, even when the AC is not in use.

The losses due to the pulley spinning are minimal, it is spinning on a bearing (~97% efficient), and belts are ~95% efficient, much more efficient than the electricity generation and running of an electric compressor motor. But the shutting down of the engine, which is the big contributor to ~70% inefficiency of the gasoline usage due to the ~30% efficiency of an IC engine is still the big saver, so some lower level losses may need to occur to accomplish the big one.

And a little discomfort on the part of the driver may be part of the compromise needed to achieve the mpg. Back in the 50's and 60's, we just opened the windows when it got too hot inside. ;-)

Electric A/C is a must if you want to drive with electricity alone - PHEV. The conversions are available if Ford doesn't want offer the option.

The complaint with Escape AC has been that average mpg goes way down in hot climates like ours in Arizona, because the AC needs to be on 10 months a year, morning noon and night, while one is driving.

Doesn't matter which design is more efficient from a kcal or overall efficiency point of view, because nobody is worrying about battery consumption at present. It's strictly gas economy that is at issue.

So I too would like to know if the 2009 model has changed to an all-electric AC.

I have read a lot of articles now on the electric a/c compressor and I have been pleasantly surprised by them. Some of the compressors being made now are much more efficient then the current belt driven ones for one simple reason. In order for the a/c to function a sufficient amount of coolant has to be compressed. Your standard gas engine runs most of its life between 800 and 2000 rpms which is relatively what the compressor is turning. Now with an electric compressor you can run it from start to finish at around 7500 rpms which, with a brush-less electric motor is not difficult at all, allows you to move your sufficient amount of coolant at a much smaller volume and thus being more efficient.

Oh and by the way, in south GA the a/c compressor gets used all day every day as well. In case that wasn't clear, a normal compressor runs more coolant at lower rpms while an electric moves less at higher rpms so the end result of coolant cfm is the same. It is just done in a different way. the electric is allowed to spin more freely at its higher rpms and that is why it is more efficient.

And about the electricity conversion loss that was mentioned; You may want to remember that even though that is true that kinetic to electric and back to kinetic has losses involved, your automobile is constantly wasting kinetic energy on the alternator. All the power generated by it is far more than enough to power all the components of the car, so adding an electric a/c compressor would only serve to utilize some of that extra energy that is being generated. Then you don't have to turn anything for the a/c that you are not already turning.

And about the electricity conversion loss that was mentioned; You may want to remember that even though that is true that kinetic to electric and back to kinetic has losses involved, your automobile is constantly wasting kinetic energy on the alternator. All the power generated by it is far more than enough to power all the components of the car, so adding an electric a/c compressor would only serve to utilize some of that extra energy that is being generated. Then you don't have to turn anything for the a/c that you are not already turning.

I guess the fact that many cars have been using electric radiator fans for years as opposed to belt driven on the front of the water pump doesn't mean anything either. Am I the only one that realizes this.

Pardon me, I'm a first-timer. Would someone point
me in the direction of putting electric a/c in my
'60 Ford F-100. Trying to get around all the belts
and pulley's. I've already converted to electric
p/s with the Toyata MR2 pump. Suggestions appreciated
Thx Bill

JDL wrote: "your automobile is constantly wasting kinetic energy on the alternator."

Wrong. The alternator may always be spinning. But power is produced only when there is a demand. There is no extra energy being generated. Only enough to satisfy demand.

I am trying to exchange my beltdriven AC compressor with a electrically driven compressor. Anyone having some suggestions on what to buy?

I guess the fact that many cars have been using electric radiator fans for years as opposed to belt driven on the front of the water pump doesn't mean anything either. Am I the only one that realizes this.

Posted by: JDL

The number one reason for the increase use of electric radiator fans is the transverse engine mount. It changes the orientation of the engine relative to the front mounted radiator making a direct drive fan impossible.

There are other advantages to using electric fans, but most longitudinal mounted engines use direct drive fans. Since the fan is most needed at low speeds or idle they are designed to perform at low rpm with advanced blade designs and/or clutches to reduce noise and engine drag at high rpm.