The rise of EVs.... some data.

[stoveliker]

I don't think these electric planes are flying at the same altitude as commercial airliners.

You may be right. But even at 3000 ft, temps are 20-30 F lower than on the ground.
Moreover, flying higher is actually more energy efficient (which is why planes that can, fly so high). So having them fly lower is a waste of energy. (And even for renewable energy that's wasteful and should be avoided.)
Finally, smaller planes don't fly long distances. And for such distances, other modes of transportation are often far better suited and far more energy efficient.

Point is, for an experiment, a trial, this is fine. But getting even more used to energy wasting short-distance flights is not the best way to deal with this - until cheap and unlimited, carbon-free energy is available. (Which, see fusion, will always be 30-50 years out...)

 

[SpaceBus]

You may be right. But even at 3000 ft, temps are 20-30 F lower than on the ground.
Moreover, flying higher is actually more energy efficient (which is why planes that can, fly so high). So having them fly lower is a waste of energy. (And even for renewable energy that's wasteful and should be avoided.)
Finally, smaller planes don't fly long distances. And for such distances, other modes of transportation are often far better suited and far more energy efficient.

Point is, for an experiment, a trial, this is fine. But getting even more used to energy wasting short-distance flights is not the best way to deal with this - until cheap and unlimited, carbon-free energy is available. (Which, see fusion, will always be 30-50 years out...)

They are using electric planes in archipelagoes where there are few bridges and not enough ferries. However, I do largely agree, you shouldn't be taking a flight when it's more efficient to drive. Unfortunately, people take two hour flights on fossil fuel burning aircraft all the time, so why not replace those with electric planes?

 

[stoveliker]

I do see your point. I think it is still wasteful (until we have cheap unlimited, etc.)

Even Boston-JFK flights go to 25 000 - 30 000 ft, The temperature is around -30 F there. So cold. And no heatpump that'll do that either.

Anyway, moot point as I don't decide what gets developed. I'm just taken aback by how much we want to try to keep our current lifestyle going, rather than recognizing there is an issue and BOTH try to improve the use of (renewable) resources AND change our lifestyle to reduce the dependence on resources.

 

[EbS-P]

I do see your point. I think it is still wasteful (until we have cheap unlimited, etc.)

Even Boston-JFK flights go to 25 000 - 30 000 ft, The temperature is around -30 F there. So cold. And no heatpump that'll do that either.

Anyway, moot point as I don't decide what gets developed. I'm just taken aback by how much we want to try to keep our current lifestyle going, rather than recognizing there is an issue and BOTH try to improve the use of (renewable) resources AND change our lifestyle to reduce the dependence on resources.

It’s more efficient to fly high. But Heating will change the efficiency equation.

 

[stoveliker]

It will mitigate some battery waste. Heating will never change the fact that flying should be done high for efficiency. Simple matter of physics.

 

[woodgeek]

As said above, heating is a solved problem: insulation. If you want, you can insulate the heck out of the cabin, AND the battery compartment. Both then only need a little heating to 'stay warm', and plenty of cooling when working. Provided by a glycol loop.

We are just not used to highly insulated CARS. But they could be built if needed.

 

[ABMax24]

IMO the battery heating issue is a non-issue. Most batteries heat up when discharging at high rates. Add a little insulation to shield it from the outside elements.

Some EV's even have to dissipate some of this heat to keep the battery cool, pump that to the cabin.

Worst case scenario install a small biofuel powered APU, dump the heat into the cabin, put the electrical output to the batteries to extend range. A couple dozen gallons of biofuel would cover most EV plane flights for heating.

 

[EbS-P]

As said above, heating is a solved problem: insulation. If you want, you can insulate the heck out of the cabin, AND the battery compartment. Both then only need a little heating to 'stay warm', and plenty of cooling when working. Provided by a glycol loop.

We are just not used to highly insulated CARS. But they could be built if needed.

I would like to see how much energy goes to heating vs cooling an EV battery pack. And see that broken down my location. 1000# plus batter has a good bit of thermal mass. My guess is more is spent heating than cooling.

 

[Ashful]

Keeping batteries with in an optimum operating temp range is a sloveable problem.

Easy... have the pilots and passengers sit on them!

 

[Ashful]

I'm just taken aback by how much we want to try to keep our current lifestyle going, rather than recognizing there is an issue...

At least in my little corner of the world, this appears to be one of the several more positive results of our response to the COVID pandemic. People made huge lifestyle changes, and at least in my world, MS Teams, Zoom, and other platforms have replaced at lot of unnecessary travel. In addition, more people working from home, fewer cavernous and inefficient office buildings lit and heated full-time...

I would like to see how much energy goes to heating vs cooling an EV battery pack. And see that broken down my location. 1000# plus batter has a good bit of thermal mass. My guess is more is spent heating than cooling.

Remember that heat can be moved from source of loss (motors, power translation) to where it's needed (batteries), meaning that not all heating requirement needs to come at the expense of battery life.

Likewise, when it's -40 outside, passive cooling becomes a pretty trivial matter. If mass is provided sufficient for storing some heat (eg. air frame), it can be expelled while at altitude.

 

[stoveliker]

Mass is generally minimized in planes... And Alu and carbon and epoxy are have a low heat capacity.

 

[woodgeek]

Existing EVs already have multiple heater/chiller loops for the cabin motor/inverter and battery, with integration where they can use the heat from one to heat one of the others, and a single AC/chiller to cool any of them (that has to be pretty large to keep the battery cool during DCFC events). My Bolt has three loops and three reservoirs. IIRC the Tesla is similar.

Even so current EV designs are optimized for warmer climates, bc that is were most current sales are. And so battery packs are NOT thermally insulated, and cabins are not thermally insulated.

The Bolt is 'undone' by the control software, which can't read my mind. In v cold weather, the car will allow the pack to get cold (to save energy/range), but then when the pack is too cold, it limits the DCFC speed. If the software would allow me to just press a 'roadtrip today' button, it could then use a little more energy to keep the pack warm, and my DCFC would go better in very cold weather. But it doesn't.
The Tesla software with integrated 'nav' and DCFC/supercharger routing KNOWS that there is a destination requiring DCFC, and keeps the car primed to an ideal temp. THIS is one reason when the Bolt has slow DCFC bc GM didn't care about getting this control right (which might cost EPA range and thus sales).

HP heaters (putting a reversing valve on the AC) is not super useful, bc they save energy when its a little cold out, but then fail in extreme cold when energy savings are most needed. KInda a goldilocks solution.

 

[peakbagger]

I do appreciate the HVAC mode on my Prime. If I am going anywhere on cold day and the car is plugged in, I just push a button on my Key fob and the cars heat pump goes on and warms up the cabin. Obviously not an option on subzero days but nice down to about 15 or 20 degrees. Anything colder than that and the heat pump does not do much. In that case, the engine starts up quickly and I get heat within a few minutes and have to rough it with seat heaters and heated steering wheel

 

[Ashful]

Mass is generally minimized in planes... And Alu and carbon and epoxy are have a low heat capacity.

Eight seconds on Google shows that most commercial airliners have a dry (curb) weight of 31,000 to 127,000 pounds, with even the newest airframes (eg. 777) being at least 50% aluminum, steel, and titanium, by weight. Seems sufficient to store at least some momentary battery-generated heat during their most demanding phase (takeoff), for expelling just several minutes later. I see conduction to and from the storage as the bigger challenge, than the storage capacity itself.

 

[stoveliker]

Yeah, but we were talking small planes. Not triple 7s. Those will be a ways out, if battery technology progress is an indicator...
Especially given the poor energy density per mass for batteries, mass will be minimized even more on planes using batteries for energy for propulsion.



There is a reason some Airbus planes are made of composites rather than pure aluminum alloys. Mass.

 

[EbS-P]

Eight seconds on Google shows that most commercial airliners have a dry (curb) weight of 31,000 to 127,000 pounds, with even the newest airframes (eg. 777) being at least 50% aluminum, steel, and titanium, by weight. Seems sufficient to store at least some momentary battery-generated heat during their most demanding phase (takeoff), for expelling just several minutes later. I see conduction to and from the storage as the bigger challenge, than the storage capacity itself.

I imagine the plane would look something like this and be about the same size. I also think green aviation flue will happen before electric planes. Maybe even hydrogen.

https://www.corporatejetinvestor.co...ine-powers-celera-500l-performance-965/?amp=1

 

[Ashful]

I imagine the plane would look something like this and be about the same size. I also think green aviation flue will happen before electric planes. Maybe even hydrogen.

https://www.corporatejetinvestor.co...ine-powers-celera-500l-performance-965/?amp=1

Agreed. But I got a kick out of the opening sentence of that article:

"RED Aircraft’s liquid cooled V12 twin six-cylinder RED A03 engine is the primary reason why the Celera 500L boasts running costs of $328 per hour with a 4,500nm range"

I suspect the author meant to indicate nautical mile, but the abbreviation he used is actually nanometers, with 4500 nm being roughly 0.0002 inches. That would certainly give some ammo to the BEV range anxiety crowd. I think he meant 4,500 nmi or NM.

 

[stoveliker]

A plane with a four and a half micron range. Now that is science fiction right there.

 

[Ashful]

Ah... isn't nerd humor fun.

 

[begreen]

I do appreciate the HVAC mode on my Prime. If I am going anywhere on cold day and the car is plugged in, I just push a button on my Key fob and the cars heat pump goes on and warms up the cabin. Obviously not an option on subzero days but nice down to about 15 or 20 degrees. Anything colder than that and the heat pump does not do much. In that case, the engine starts up quickly and I get heat within a few minutes and have to rough it with seat heaters and heated steering wheel

Yes, the Volt lets you do this from an app. It was great on my commute home in winter. I would tell the car to warm itself up about 5 minutes before I arrive.

 

[begreen]

I imagine the plane would look something like this and be about the same size. I also think green aviation flue will happen before electric planes. Maybe even hydrogen.

https://www.corporatejetinvestor.co...ine-powers-celera-500l-performance-965/?amp=1

Fasten your seat belts.

Alice, the first all-electric passenger airplane, takes flight | CNN Business

The world's first all-electric passenger aircraft has successfully taken to the sky.

www.cnn.com

 

[ABMax24]

I'll take one of these please:

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[Ashful]

I'll take one of these please:

I've seen a hell of a lot of crashed 4-rotor drones, sometimes due to nothing but an errant breeze. I've also observed the fact that a significantly large fraction of our driving population have no business getting behind the wheel of a car that stays on the ground. When combined, these two factors don't paint a picture for success.

Hopefully autonomous control of such vehicles is built into the plan.

 

[GrumpyDad]

You may be right. But even at 3000 ft, temps are 20-30 F lower than on the ground.
Moreover, flying higher is actually more energy efficient (which is why planes that can, fly so high). So having them fly lower is a waste of energy. (And even for renewable energy that's wasteful and should be avoided.)
Finally, smaller planes don't fly long distances. And for such distances, other modes of transportation are often far better suited and far more energy efficient.

Point is, for an experiment, a trial, this is fine. But getting even more used to energy wasting short-distance flights is not the best way to deal with this - until cheap and unlimited, carbon-free energy is available. (Which, see fusion, will always be 30-50 years out...)

Well, they are also able to get above some weather, it gives them more options to fly through developing weather, and you avoid more critters, not to mention yahoos who fly once in a blue moon.
Leer jets can fly above many thunderstorms, whereas commercial airliners generally cannot fly above big storms.

 

[GrumpyDad]

I'll take one of these please:

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no thanks.
The only thing that helmet is going to do is frustrate EMS when they come to ident his body.