Before I dig any further into this. What is the average FE reduction while using a/c? Both in ECO mode, normal mode and max?


while I'm here, I found this unit.
DC Airco type 4400 is designed and used for cooling small cabs, and sleeper cabs of (EU) trucks.
DC 4400 is a small lightweight dc air conditioner introduced in 1998, and modified in 2003.

DC 4400 12 volt
DC 4400 24 volt

Cooling capacity
1300 Watt – 4400 BTU
1400 Watt – 4760 BTU

Power consumption
360 Watt 30A
360 Watt 15A

Size mm

Size inches
700 W x 920 D x 265 H

27,5W x 36,3 D x 10,5 H
700 W x 920D x 265 H

27,5W x 36,3 D x 10,5 H

Weight
30kg / 66 lbs
30 kg / 66 lbs

Max. outdoor ambient
40 ºC / 104 ºF
40 ºC / 104 ºF

Low voltage settings

(Unit will shut down if there is a low voltage)
12 VDC = 10,5 volt

24 VDC = 21,5 volt

Restart settings

(If there was a low voltage the unit will restart at)
12 VDC = 12,6 volt

24 VDC = 25,2 volt


High pressure switch
24 bar
24 bar

Low pressure switch
2 bar
2 bar

Safety switches
Max. temperature compressor and motor
Max. temperature compressor and motor

Coolant/ refrigerant
R134a
R134a

http://www.dcairco.com/DC4400.html

Figure we would need about 3000 - 3400 BTU's, this is 4400, a nice safety margin of error.

 

If the engine is running the MOST efficient way of running the A/C pretty much has to be directly off the ICE. Its a simple matter of energy (all power comes from the engine--none of it is free, even the regen is recaptured ICE drive energy that would have been burned up heating the brake pads).... it will be more efficient to pump the compressor directly rather than turn a generator, make electricity, store it in a battery, turn another electric motor to pump a compressor... there are losses all along that path. The hybrid systems efficiency comes from no idles, recaptured braking energy, and load balancing when the ICE is on....

If you have alot of different loads and speeds on the compressor then presumably you'd need differing RPM and torques to turn it at the best output. The FEH plays that balance in its transmission by balancing high torque low RPM electric effiency against high RPM lower torque ICE efficiency... the transmission makes those decisions for driving the wheels all the time.... but you aren't going to build such a system from scratch for your A/C.

I think hooking up ones own electric A/C in some homemade way might end up making one more comfy... but I doubt its going to do anything for your gas mileage.

 

You know, it just isn't the Ford design, and we need to live with it. I hate it when I have to shut off ECON, as I do in hot weather when the family is in the car, but that is just the way the vehicle is designed.

I don't see that it is possible to bring up a practical A/C unit not incorporated into the Ford design.

If you want electric A/C, buy a Toyota or Honda...

 

Toyota's and Honda's are nice. We even considered a HCHII but opted for the FEH because we needed the larger vehicle. Right now this is just curiosity and brainstorming to see if it would be beneficial to FE. As for practicality, that comes in after weighing the possible benefits.

 

Running the A/C compressor directly from the ICE will always be more efficient than using the ICE to charge the battery and then converting the battery charge back into mechanical energy to run the compressor.

But then you must consider that the battery is sometimes being charged for "free".

When you cycle a compressor on and off to modulate, moderate, the liquification/flow of refrigerant it will take about 2.5 times the operating energy to restart it against the previously built up head pressure. In other words you would need a ~3000 watt inverter to run that 10,000 BTU A/C.

Which is undoubtedly another reason Toyota uses the variable speed electric A/C compressor drive. Variable speed equals no BUMP LOAD (re)start effort.

 

I'm trying to weigh the diferences between running the mechanical ICE A/C compressor or an electrically driven A/C. I understand the inherient loses in having the ICE run the alternator/generator to charge the battery to run the a/c but I'm curious to see if they are even with the loses running the ICE to run the mechanical a/c compressor.

The perfect or semi perfect test would be running a FEH on a course with:
1. FEH no a/c
2. FEH with a/c
3. FEH with a/c in econ mode
4. FEH running 4400 BTU 360W 30A electric a/c

A 3000 BTU unit would be preferable but I haven't been able to find one online yet.

What is the average FE drop when using a/c in both econ and regular modes?

 

another potential problem is what to do with the heat generated by the portable ac unit. it would have to duct it out of the car somehow or you would make the car hotter.

 

On a 2008 there is a recirculate button. That helps to keep it cool inside longer when using the A/C because you are recirculating cooler air inside than outside.

 

Thats something to consider but not at this point in the process. One thing at a time, need to get FE numbers.

 

You have to keep in mind here that of the three things a Hybrid does to work its magic...

-Regenerative Braking

-EV Assist to allow for less ICU load (and to allow for the Atkinson cycle without horrible low end torque)

and

-ICE Shutdown at stops,

The third (ICE Shutdown at stops) makes the least impact on fuel economy improvement... unless, of course you let the engine idle for long periods of time.

Being that the A/C being run off of the engine is more efficient than electric A/C (it's also much easier on the electrical system), and given the nightmare of venting an electric A/C unit (which also might cause more wind resistance in the process)... I don't think you're going to save any fuel by trying this out.

You have to keep in mind that ANY air conditioner is going to produce more heat than it removes. Belt-driven automotive A/C systems cope with this by using the condenser mounted in front of the radiator. An electrical A/C unit has the condenser built into it with an electric fan blowing air through it. This would have to be routed through a large hose outside, or it would cause the interior of the car to heat up, not cool off.

An open window with a ventilation hose sticking out of it would not only look more goofy than a Disney character, it would also disrupt the aerodynamics of the vehicle.