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Comment Re:Why not both? (Score 1) 235 235

Offer void where constant-speed is not the most efficient. Pumps and fans that can match the actual demand by varying speed will be more efficient than running a full out and bypassing or artificially increasing head pressure to get the desired flow.

You're also not going to put an across-the-line starter on a motor larger than about 50HP unless you like replacing equipment. You'll always have a soft starter to get things going - this is doubly important if you're starting the motor under load.

Comment Re:"We have a profound opportunity to distort." (Score 1) 61 61

It will also vary depending on the performance of the vehicles immediately ahead of, oncoming-and-passing, or crossing ahead of the street view vehicle. Especially the first: The sensor will be running in the exhaust plumes of the vehicles ahead of the street view car, so the map will be a very non-random sampling.

On the other hand, the partculate and "volatile organic compounds" sensors will produce some very interesting data. The latter is what the federal standards call "unburned hydrocarbons" when emitted from an engine, and the output of modern engines is vanishingly small. But many species of evergreen trees emit them in enormous quantity, as part of their ongoing chemical warfare against insects that eat trees. That's what the blue haze around pine-forested mountains (such as "the Smoky Mountains") is about. You can literally destroy (by extreme and long-term contamination) an automotive conformance test cell (the room where they test the car's emissions), requiring it to be torn out and rebuilt, by placing a Christmas tree in it overnight.

I expect some towns in remote, forested, mountain areas, where people move "for their health" and "for the clean, fresh, air", to get a rude awakening. B-)

But I doubt it will affect the extremely tight standards for automobile engines - except maybe to cause a flap that tightens them further. These days many engines are so clean that running then can IMPROVE the air quality in some places (such as portions of Los Angeles, with topography that created such a thermal inversion that a single settler's campfire could leave the whole valley filled with smoke for a day or more) by inhaling and burning far more hydrocarbon and particulate pollutants than they create.

Comment Re:Why not both? (Score 1) 235 235

So called Brushless DC motors are actually permanent magnet rotor, synchronous AC motors?

They are virtually identical, yes. There might be some nuanced differences in their physical construction or drive (sinusoidal vs trapezoidal waveform, for example) but the operational principle is the same.

For fractional horsepower motors there's no cost-benefit to doing sophisticated controls in most cases. You just need it to turn on and off at one, sometimes two or three speeds and the load is more or less constant. I wouldn't expect that to change any time soon.

Comment Re:Efficiency (Score 1) 868 868

Flywheels can be charged up lots faster than batteries.

That depends entirely on the design of the flywheel/battery. But you know what flywheels do better than batteries? Leak. An idle flywheel will lose energy much faster than an idle battery.

Supercapacitors are neat but have the worst volumetric energy efficiency of then all.

Comment Re:Efficiency (Score 1) 868 868

But for the cost and weight, a battery is better than a flywheel in essentially every aspect. For however much you reduce the required size of a flywheel, you can reduce the battery size as well.

Battery systems are damn close to 100% efficient if you're not too close to fully charged or fully discharged, or not diving the current much higher than 1.0C.

There is no advantage to using a flywheel at all. None.

Comment Re:Easy Conclusion If Perceived Costs & Range (Score 1) 868 868

In 2013, the average price for a new car was $32K. Many EVs available right now are below that even *before* any state or federal incentives, and many more hit that point after incentives.

Meanwhile, the average price for a used car was $16.8K. I don't know where you'd get a sub-$10K used vehicle from a reputable source (versus a cash transaction in someone's driveway...)

Comment Lots of room for methodology issues. (Score 2) 293 293

The lack of accidents and crime are more likely related to a general trend in crime going down from before they started turning off the lights. ... Give me at least one full year worth of data so I can compare it to the prior year, and have half of the country keep their lights on so It can be compared to the same time frame as well.

Hear, hear!

There's lots of room for methodology errors. Here's another:

Comparing murder rates between Great Britain and the US is complicated by differences in reporting. The US bumps the murder stat when there is a body and evidence of foul play. G.B. bumps it when they have a conviction.

Do they do that with other crime? If so, stable stats in the absence of street lighting might mean that any rise in crime is compensated for by a fall in identifying, apprehending, and convicting the criminals responsible. (Indeed, turning off the lights might easily result in LOWERED crime statistics at the same time it was causing a drastic increase in actual crime.)

Comment Re:Efficiency (Score 1) 868 868

Consider replacing the electric commuter-car battery with a flywheel. We have the tech to do this for ranges of 50 miles or so.

Why would you, though? Flywheels have atrocious energy densities.

We should be thinking about replacing batteries with "fuel cells", because, like hydrocarbon engines, only fuel (most agree hydrogen is best) needs to be carried around, and the waste (H2O) can be dumped.

Wrong. A fuel cell car also needs a sizable battery, because a fuel cell capable of providing sufficient output for acceptable performance would be massive and expensive. A battery needs to be included to provide the peak power and the fuel cell basically acts as an on board generator to keep it topped off.

And given that, it's a waste. For all the solar energy you collected to make and process the hydrogen, you could have put that directly into an EV's battery and come out way ahead.

Comment Re:Why not both? (Score 1) 235 235

if you're going to have an internal module that "generates whatever voltages are needed" then you're just going through the conversions again, and you're saving nothing on efficiency (and losing a lot on costs).

The only way it'll work is if the DC input, eg solar panels, is matched to the unit's requirements. Anything other than that and you're just running in circles.

Comment What hospital is that? (Score 1) 54 54

I'm an anesthesiologist. I put people to sleep for cardiac surgery. My hospital does around 400-500 hearts a year... and we don't kill any dogs.

What hospital is that? I'll want to avoid it if I ever need heart surgery.

Seriously: How does your cardiac unit's mortality and morbidity rate stack up against those of hospitals where practice surgery on live animal, models, at least where the surgeon is new to the procedure, is more common?

Comment Re:Solar Powered Aircon (Score 1) 235 235

Of course you can power everything with heat. Indeed, nearly everything *is* powered with heat; Most conventional power plants use thermal processes, converting heat energy into mechanical energy then into electrical energy.

A solar powered refrigerator (or any refrigeration cycle driven directly by heat) allows the use of fairly low quality heat sources to do useful work without losses converting it to electricity first. Very useful in some circumstances.

Comment Re:Why not both? (Score 3, Informative) 235 235

And yet, in practice, HVDC is still more efficient than current AC lines in the end, even if still somewhat more expensive at the moment.

Yes and no.

AC power is far more efficient at higher voltage and short to medium distances, and you save a lot of material (and thus money) on conductor sizes. The voltage can be changed easily and it is safer and easier to switch on and off since there's 50 or 60 times per second where the voltage/current is zero - allowing for the circuit to be opened without arcing or inductive voltage spikes. AC arcs also tend to be self-extinguishing for this reason.

But AC systems also have inductance and capacitance to deal with. For very high power, very long distance runs, the capacitive losses start to add up. More current is required to charge/discharge this inherent capacitance, which means more power losses. This is where HVDC really shines.

Comment Re:Animals (Score 1) 54 54

I'm an anesthesiologist. I put people to sleep for cardiac surgery. My hospital does around 400-500 hearts a year... and we don't kill any dogs.

So maybe I'm not up to date, or things are/were different in research hospitals.

My personal info was based on stories told by my mother, in about the '60s, when she was a special duty RN at the University of Michigan hospital, often handling cardiac recovery.

My favorite was the one where the UofMich hospital cafeteria, which had been purely open seating, established separate rooms for the staff to eat after an incident where patients' families overheard, and were traumatized by, a cardiac surgeon's response to a question. Asked how his operations the previous day had gone (referring to his experimental and/or practice surgery on a collie and another dog), he said "The blonde lived but the old bitch died."

The kids and adopted dogs story was from my wife. The surgeon in question was Dr. Albert Starr in (at least) the '60s through '80s. He was at St. Vincent's and also flew, with his team, to operate at a number of other west coast hospitals, university and otherwise.

Function reject.