Air conditioner usage

[qbee42]

Originally Posted by anne1965

Yes, it is relevant. The fact that the compressor is electrically driven means that it can be driven at exactly the right load.

<snip>

No, it's not relevant in any shape or form. The central theme of this discussion revolves around the efficiency of the Prius A/C. How the Prius achieves that efficiency is a fascinating tangent, but a tangent none the less. The Prius could use black magic and stardust to achieve the same efficiency curve and the argument would remain exactly the same.

This is a common trap in discussions. People get lost in the details, even when the details are not relevant, which is why we, as engineers and scientists, often use black box diagrams. The black box hides the distracting detail. In this case, the A/C system is the black box. How the box performs is important. What's inside the box doesn't matter.

Tom

[anne1965]

Originally Posted by qbee42

No, it's not relevant in any shape or form. The central theme of this discussion revolves around the efficiency of the Prius A/C. How the Prius achieves that efficiency is a fascinating tangent, but a tangent none the less. The Prius could use black magic and stardust to achieve the same efficiency curve and the argument would remain exactly the same.

This is a common trap in discussions. People get lost in the details, even when the details are not relevant, which is why we, as engineers and scientists, often use black box diagrams. The black box hides the distracting detail. In this case, the A/C system is the black box. How the box performs is important. What's inside the box doesn't matter.

Tom

That clears it up. Looking at the original post of bokone, I interpreted the 'belt-less electric A/C compressor' to mean 'very efficient A/C'.

[qbee42]

Originally Posted by anne1965

That clears it up. Looking at the original post of bokone, I interpreted the 'belt-less electric A/C compressor' to mean 'very efficient A/C'.

Which of course it is. The Prius A/C compressor has many advantages: belt-less, variable speed, direct drive, and hermetically sealed with no moving seals. It doesn't get much better than that at this stage of A/C development.

Tom

[namasteflc]

Air coonditioning takes horsepower: in the older(non-Prius) sedans, about 5 horsepower. Because we have electric a/c compressors means that we also have more efficiency losses: electric generator: battery: inverter: electric motor, as well as compressor losses that everyone else has. At least we don't have a belt loss.
I'm not sure if our electric a/c compressor is modulating; there are other efficiency losses if an a/c compressor isn't run at optimum rpm.