A/C box

"inverter compressor"

fredag den 23. juni 2023 kl. 22.09.05 UTC+2 skrev RichD:

instead of running the compressor at a fixed high speed set by the mains frequency it uses an inverter to generate a variable frequency 3 phase AC to run the compressor at the just right speed needed for the load

at one point there was talk about switching cars to 42V with a big combined starter generator that way all the accessories could be electrical and mounted where convenient instead of where it could be driven by a belt

for AC that would also enable variable speed and a hermetically sealed compressor with out fancy seals on an input shaft that have to hold high side refrigerant pressure

The compressor is driven by a VFD (which they call a variable speed inverter)

This is not new Air Con technology, but may be new to through-wall units.

Switchers use bang/bang for greater efficiency vs. linear.

Oh, great, now we'll be completely inundated with crappy unfiltered Chinese variable-frequency drives. Talk about an EMI nightmare.

Cheers

Phil Hobbs

Quit your bitchin'. They will all have UL and FCC and CE stickers.

The idea of directed cooling is not very functional. My car is rather cavernous, as opposed to a smallish cab pickup truck I used to drive. I notice when going around turns, that the air does not fully turn with the car and I am suddenly sitting in hot/cold air, when I was sitting in cool/warm air. Cars of any size will have this effect that mitigate the effectiveness of trying to just cool the occupants.

There must be an obvious A/C energy saving in EV.

They have heated seats, so....

This raises an interesting question of human biology and perception. A/C is primarily an issue of perception, comfort. Then, which surfaces of the body are most sensitive to temperature? I don't know of any research on this. But it might offer large energy efficiencies for cooling.

On Friday, 23 June 2023 at 17:26:42 UTC-7, Ricky wrote: ...

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My Prius has that feature.

A control button allows conditioning either for just the driver or all occupants.

I don't know how much it reduces energy consumption but I've never noticed any issue with it.

The Prius is a hybrid so the A/C compressor is powered electrically with an inverter from the traction battery. I don't know over what speed range it operates.

kw

Yes, there is. In an ICE, all power ultimately comes from the gasoline, converted by the engine to mechanical power. This is VERY inefficient, around 25 to 30%, typically. In the BEV, the electricity runs a compressor thorough an electric motor, all with very good efficiency.

It is the efficiency of converting electrical power to other forms, that reduces the pollution caused by BEVs, even when that electricity is generated from fossil fuels.

And in some cars, cooled seats.

I don't think it works that way. If find in my model X, in the winter, my left foot tends to be cold and there's nothing I can do to mitigate this. I never had it in my T100, where tons of heat was available, or any other car that I can recall.

One thing about the Teslas that I think shows the difference between a startup and a long term automaker, is the lack of attention to details. The poor circulation of warm air by the floor, is one of those. The electric drive train is nothing short of amazing. But the rest of the car is... a car.