The Death Of Fossil Fuels

Discussions about serious topics, for serious people
Post Reply
User avatar
dyqik
Light of Blast
Posts: 5223
Joined: Wed Sep 25, 2019 4:19 pm
Location: Masshole
Contact:

Re: The Death Of Fossil Fuels

Post by dyqik » Thu Feb 24, 2022 5:06 pm

Oh, and furnaces are not the same thing as boilers. Boilers here either generate steam for steam radiators (common in older houses), or hot water for radiators (uncommon, usually baseboard radiator), or radiant underfloor heating (maybe more common than radiators, in newer houses in climates where AC isn't required). Furnaces directly heat air and send it through ducts around the house (probably the most common form of heating built into houses over the past century).

Replacing or supplementing a furnace with a heat pump to add central AC and moderate temperature heating is common - the cost differential between adding/replacing AC and adding a heat pump is essentially zero with the available rebates and tax credits. The running costs of natural gas furnaces are still lower than heat pumps in winter - the break-even is about a COP of 4 with our electricity and gas prices here over the past few years. But for oil or propane - which covers a lot of houses, as many places do not have gas supply pipes, the break-even COP is about 2.

For houses built without air ducts for a furnace, it's more common to install mini-split heat pumps, at least up here where most houses are multi-storey and often don't have enough attic space for ducts. Where houses are more commonly single level (e.g. Texas), it's usually easy enough to install ducts in the attics.

Holylol
Sindis Poop
Posts: 59
Joined: Tue Nov 19, 2019 10:14 am

Re: The Death Of Fossil Fuels

Post by Holylol » Fri Feb 25, 2022 9:15 am

Quick question on the definition of the COP that is announced by manufacturers for heat pump:
Is it defined as the ratio of heat power produced to mechanical power provided by the compressor? Or is it the ratio of heat power produced to electrical power provide to the compressor?
(so, is the compressor efficiency accounted for in the COP?)

User avatar
dyqik
Light of Blast
Posts: 5223
Joined: Wed Sep 25, 2019 4:19 pm
Location: Masshole
Contact:

Re: The Death Of Fossil Fuels

Post by dyqik » Fri Feb 25, 2022 11:41 am

Holylol wrote:
Fri Feb 25, 2022 9:15 am
Quick question on the definition of the COP that is announced by manufacturers for heat pump:
Is it defined as the ratio of heat power produced to mechanical power provided by the compressor? Or is it the ratio of heat power produced to electrical power provide to the compressor?
(so, is the compressor efficiency accounted for in the COP?)
In the spec sheet for my heat pump, it's stated COP is equal to output heat/wall plug power. Resistive electric heat is also widely stated to have a COP of 1.0.

FlammableFlower
Dorkwood
Posts: 1239
Joined: Mon Nov 11, 2019 1:22 pm

Re: The Death Of Fossil Fuels

Post by FlammableFlower » Tue Mar 15, 2022 3:32 pm

[urlhttps://www.theguardian.com/environment/2022/ma ... l-security]Hell's teeth they're slow, aren't they?[/url] I suppose we should be just a little bit thankful that some Tories are waking up to the idea that more renewables are a good thing...

User avatar
TimW
Snowbonk
Posts: 460
Joined: Mon Nov 11, 2019 4:27 pm

Re: The Death Of Fossil Fuels

Post by TimW » Sat Apr 23, 2022 11:35 am

Some peeps are claiming to have developed hydrogen tanks for aircraft...
that have demonstrated a 75% mass reduction compared to existing state-of-the-art aerospace cryotanks (metal or composite).
...
enabling H2-powered aircraft and eVTOL manufacturers to store as much as 10 times more LH2 fuel without adding mass.
https://www.compositesworld.com/news/hy ... ogen-tanks

Could be bit of a game-changer.
An aircraft equipped with GTL dewar tank technology could achieve as much as four times the range of a conventional aircraft using aviation fuel, cutting aircraft operating costs by an estimated 50% on a dollar-per-passenger-mile basis.

User avatar
Grumble
Stummy Beige
Posts: 3105
Joined: Mon Nov 11, 2019 1:03 pm

Re: The Death Of Fossil Fuels

Post by Grumble » Sat Apr 23, 2022 12:02 pm

TimW wrote:
Sat Apr 23, 2022 11:35 am
Some peeps are claiming to have developed hydrogen tanks for aircraft...
that have demonstrated a 75% mass reduction compared to existing state-of-the-art aerospace cryotanks (metal or composite).
...
enabling H2-powered aircraft and eVTOL manufacturers to store as much as 10 times more LH2 fuel without adding mass.
https://www.compositesworld.com/news/hy ... ogen-tanks

Could be bit of a game-changer.
An aircraft equipped with GTL dewar tank technology could achieve as much as four times the range of a conventional aircraft using aviation fuel, cutting aircraft operating costs by an estimated 50% on a dollar-per-passenger-mile basis.
Awesome, the future is coming
Would you like your chakras realigned?

User avatar
jimbob
Stummy Beige
Posts: 3742
Joined: Mon Nov 11, 2019 4:04 pm
Location: High Peak/Manchester

Re: The Death Of Fossil Fuels

Post by jimbob » Sat Apr 23, 2022 12:10 pm

TimW wrote:
Sat Apr 23, 2022 11:35 am
Some peeps are claiming to have developed hydrogen tanks for aircraft...
that have demonstrated a 75% mass reduction compared to existing state-of-the-art aerospace cryotanks (metal or composite).
...
enabling H2-powered aircraft and eVTOL manufacturers to store as much as 10 times more LH2 fuel without adding mass.
https://www.compositesworld.com/news/hy ... ogen-tanks

Could be bit of a game-changer.
An aircraft equipped with GTL dewar tank technology could achieve as much as four times the range of a conventional aircraft using aviation fuel, cutting aircraft operating costs by an estimated 50% on a dollar-per-passenger-mile basis.

This seems surprising:
"Based on our internal analysis of a De Havilland Canada Dash 8 Q300, which seats 50 to 56 passengers, the standard PW123B engine would typically support a range of 1,558 kilometers,” said Sergei Shubenkov, co-founder and head of R&D at HyPoint. “By implementing HyPoint's system and a standard liquid hydrogen tank, the same aircraft could achieve five hours of flight time or a max range of 2,640 kilometers. With GTL's tank, it could fly for 8.5 hours or a max range of 4,488 kilometers, indicating that this aircraft could fly three times further with zero emissions by using HyPoint and GTL compared with conventional aviation fuel," "That's the difference between this plane going from New York to Chicago with high carbon emissions versus New York to San Francisco with zero carbon emissions."
How is the hydrogen managing to achieve a greater range than kerosene? Even with a standard H2 tank and their "HyPoint system"?

If it works for aerospace, would that also work for other systems? I'm thinking marine engines.
Have you considered stupidity as an explanation

User avatar
Grumble
Stummy Beige
Posts: 3105
Joined: Mon Nov 11, 2019 1:03 pm

Re: The Death Of Fossil Fuels

Post by Grumble » Sat Apr 23, 2022 12:39 pm

jimbob wrote:
Sat Apr 23, 2022 12:10 pm
TimW wrote:
Sat Apr 23, 2022 11:35 am
Some peeps are claiming to have developed hydrogen tanks for aircraft...
that have demonstrated a 75% mass reduction compared to existing state-of-the-art aerospace cryotanks (metal or composite).
...
enabling H2-powered aircraft and eVTOL manufacturers to store as much as 10 times more LH2 fuel without adding mass.
https://www.compositesworld.com/news/hy ... ogen-tanks

Could be bit of a game-changer.
An aircraft equipped with GTL dewar tank technology could achieve as much as four times the range of a conventional aircraft using aviation fuel, cutting aircraft operating costs by an estimated 50% on a dollar-per-passenger-mile basis.

This seems surprising:
"Based on our internal analysis of a De Havilland Canada Dash 8 Q300, which seats 50 to 56 passengers, the standard PW123B engine would typically support a range of 1,558 kilometers,” said Sergei Shubenkov, co-founder and head of R&D at HyPoint. “By implementing HyPoint's system and a standard liquid hydrogen tank, the same aircraft could achieve five hours of flight time or a max range of 2,640 kilometers. With GTL's tank, it could fly for 8.5 hours or a max range of 4,488 kilometers, indicating that this aircraft could fly three times further with zero emissions by using HyPoint and GTL compared with conventional aviation fuel," "That's the difference between this plane going from New York to Chicago with high carbon emissions versus New York to San Francisco with zero carbon emissions."
How is the hydrogen managing to achieve a greater range than kerosene? Even with a standard H2 tank and their "HyPoint system"?

If it works for aerospace, would that also work for other systems? I'm thinking marine engines.
It’s possible that this fuel tank is bigger than the kerosene tanks, but it doesn’t look like it’ll fit in the wings, so either it takes up passenger/cargo space or it gets slung under the wings and increases drag. Another factor is an electrical motor is a lot lighter than a combustion engine so it might make some savings there.
Would you like your chakras realigned?

User avatar
dyqik
Light of Blast
Posts: 5223
Joined: Wed Sep 25, 2019 4:19 pm
Location: Masshole
Contact:

Re: The Death Of Fossil Fuels

Post by dyqik » Sat Apr 23, 2022 12:43 pm

The energy density by weight of hydrogen is 2.8 times that of gasoline or jet fuel, so if the tank is a bit less than half the weight of the hydrogen, you get a factor of 2 in energy storage per kg.

To that you can add another factor of about two for efficiency improvements of fuel cells and electric motors vs combustion engines.

I don't think volume is the limiting factor in aircraft cargo capacity, but weight.

User avatar
jimbob
Stummy Beige
Posts: 3742
Joined: Mon Nov 11, 2019 4:04 pm
Location: High Peak/Manchester

Re: The Death Of Fossil Fuels

Post by jimbob » Sat Apr 23, 2022 1:08 pm

dyqik wrote:
Sat Apr 23, 2022 12:43 pm
The energy density by weight of hydrogen is 2.8 times that of gasoline or jet fuel, so if the tank is a bit less than half the weight of the hydrogen, you get a factor of 2 in energy storage per kg.

To that you can add another factor of about two for efficiency improvements of fuel cells and electric motors vs combustion engines.

I don't think volume is the limiting factor in aircraft cargo capacity, but weight.
Volume is pretty important when air resistance is such a large factor in power usage.
Have you considered stupidity as an explanation

User avatar
TimW
Snowbonk
Posts: 460
Joined: Mon Nov 11, 2019 4:27 pm

Re: The Death Of Fossil Fuels

Post by TimW » Sat Apr 23, 2022 2:58 pm

The Airbus plan for hydrogen involves a tank in the body of the plane at the rear. The normal way to add volume to a plane is by a stretch, so that's a similar transformation. I assume it doesn't dramatically affect air resistance?

User avatar
shpalman
Princess POW
Posts: 6879
Joined: Mon Nov 11, 2019 12:53 pm
Location: One step beyond

Re: The Death Of Fossil Fuels

Post by shpalman » Sat Apr 23, 2022 3:06 pm

The previous discussion in this thread started back here I think.
molto tricky

User avatar
dyqik
Light of Blast
Posts: 5223
Joined: Wed Sep 25, 2019 4:19 pm
Location: Masshole
Contact:

Re: The Death Of Fossil Fuels

Post by dyqik » Sat Apr 23, 2022 4:19 pm

jimbob wrote:
Sat Apr 23, 2022 1:08 pm
dyqik wrote:
Sat Apr 23, 2022 12:43 pm
The energy density by weight of hydrogen is 2.8 times that of gasoline or jet fuel, so if the tank is a bit less than half the weight of the hydrogen, you get a factor of 2 in energy storage per kg.

To that you can add another factor of about two for efficiency improvements of fuel cells and electric motors vs combustion engines.

I don't think volume is the limiting factor in aircraft cargo capacity, but weight.
Volume is pretty important when air resistance is such a large factor in power usage.
It's not when installing the tank doesn't change the volume of the plane

User avatar
Gfamily
Stummy Beige
Posts: 3811
Joined: Mon Nov 11, 2019 1:00 pm
Location: NW England

Re: The Death Of Fossil Fuels

Post by Gfamily » Sat Apr 23, 2022 5:17 pm

dyqik wrote:
Sat Apr 23, 2022 12:43 pm
The energy density by weight of hydrogen is 2.8 times that of gasoline or jet fuel, so if the tank is a bit less than half the weight of the hydrogen, you get a factor of 2 in energy storage per kg.

To that you can add another factor of about two for efficiency improvements of fuel cells and electric motors vs combustion engines.

I don't think volume is the limiting factor in aircraft cargo capacity, but weight.
I saw a figure that if the Saturn V rocket burned Liquid Hydrogen rather than RP1 (kerosene), the LH tank would need to be 7x larger (almost twice as large in each dimension).
My avatar was a scientific result that was later found to be 'mistaken' - I rarely claim to be 100% correct
ETA 5/8/20: I've been advised that the result was correct, it was the initial interpretation that needed to be withdrawn
Meta? I'd say so!

User avatar
dyqik
Light of Blast
Posts: 5223
Joined: Wed Sep 25, 2019 4:19 pm
Location: Masshole
Contact:

Re: The Death Of Fossil Fuels

Post by dyqik » Sat Apr 23, 2022 7:44 pm

Gfamily wrote:
Sat Apr 23, 2022 5:17 pm
dyqik wrote:
Sat Apr 23, 2022 12:43 pm
The energy density by weight of hydrogen is 2.8 times that of gasoline or jet fuel, so if the tank is a bit less than half the weight of the hydrogen, you get a factor of 2 in energy storage per kg.

To that you can add another factor of about two for efficiency improvements of fuel cells and electric motors vs combustion engines.

I don't think volume is the limiting factor in aircraft cargo capacity, but weight.
I saw a figure that if the Saturn V rocket burned Liquid Hydrogen rather than RP1 (kerosene), the LH tank would need to be 7x larger (almost twice as large in each dimension).
That's energy density by volume, not by weight. And the tank weights would have been much higher with 50s/60s tech.

User avatar
Gfamily
Stummy Beige
Posts: 3811
Joined: Mon Nov 11, 2019 1:00 pm
Location: NW England

Re: The Death Of Fossil Fuels

Post by Gfamily » Sat Apr 23, 2022 7:52 pm

dyqik wrote:
Sat Apr 23, 2022 7:44 pm
Gfamily wrote:
Sat Apr 23, 2022 5:17 pm
dyqik wrote:
Sat Apr 23, 2022 12:43 pm
The energy density by weight of hydrogen is 2.8 times that of gasoline or jet fuel, so if the tank is a bit less than half the weight of the hydrogen, you get a factor of 2 in energy storage per kg.

To that you can add another factor of about two for efficiency improvements of fuel cells and electric motors vs combustion engines.

I don't think volume is the limiting factor in aircraft cargo capacity, but weight.
I saw a figure that if the Saturn V rocket burned Liquid Hydrogen rather than RP1 (kerosene), the LH tank would need to be 7x larger (almost twice as large in each dimension).
That's energy density by volume, not by weight. And the tank weights would have been much higher with 50s/60s tech.
Yes, obviously; but 7x the fuel volume (even if not adding fuel weight) has to go somewhere. So either there will be longer bodies of the same cross section (7x longer?), or wider bodies.
Or the need for a significant reduction in payload volume.
My avatar was a scientific result that was later found to be 'mistaken' - I rarely claim to be 100% correct
ETA 5/8/20: I've been advised that the result was correct, it was the initial interpretation that needed to be withdrawn
Meta? I'd say so!

User avatar
dyqik
Light of Blast
Posts: 5223
Joined: Wed Sep 25, 2019 4:19 pm
Location: Masshole
Contact:

Re: The Death Of Fossil Fuels

Post by dyqik » Sat Apr 23, 2022 8:13 pm

Gfamily wrote:
Sat Apr 23, 2022 7:52 pm
dyqik wrote:
Sat Apr 23, 2022 7:44 pm
Gfamily wrote:
Sat Apr 23, 2022 5:17 pm

I saw a figure that if the Saturn V rocket burned Liquid Hydrogen rather than RP1 (kerosene), the LH tank would need to be 7x larger (almost twice as large in each dimension).
That's energy density by volume, not by weight. And the tank weights would have been much higher with 50s/60s tech.
Yes, obviously; but 7x the fuel volume (even if not adding fuel weight) has to go somewhere. So either there will be longer bodies of the same cross section (7x longer?), or wider bodies.
Or the need for a significant reduction in payload volume.
Does that affect the actual limits on capacity?

User avatar
jimbob
Stummy Beige
Posts: 3742
Joined: Mon Nov 11, 2019 4:04 pm
Location: High Peak/Manchester

Re: The Death Of Fossil Fuels

Post by jimbob » Sat Apr 23, 2022 9:35 pm

dyqik wrote:
Sat Apr 23, 2022 8:13 pm
Gfamily wrote:
Sat Apr 23, 2022 7:52 pm
dyqik wrote:
Sat Apr 23, 2022 7:44 pm


That's energy density by volume, not by weight. And the tank weights would have been much higher with 50s/60s tech.
Yes, obviously; but 7x the fuel volume (even if not adding fuel weight) has to go somewhere. So either there will be longer bodies of the same cross section (7x longer?), or wider bodies.
Or the need for a significant reduction in payload volume.
Does that affect the actual limits on capacity?
If you have wider bodies, then you're affecting the air resistance. Which is important at the start.
Have you considered stupidity as an explanation

User avatar
Gfamily
Stummy Beige
Posts: 3811
Joined: Mon Nov 11, 2019 1:00 pm
Location: NW England

Re: The Death Of Fossil Fuels

Post by Gfamily » Sat Apr 23, 2022 9:46 pm

The A320 has a cargo capacity of about 37m^3
Replacing the 27,000 litres of fuel capacity with ~190,000 litres of LH is going to take all of that and more.

ETA Clearly, it's not going to be a straight swap, but as a back of the envelope calculation, I don't think it's too far out to say "it's not going to make a negligible difference"
My avatar was a scientific result that was later found to be 'mistaken' - I rarely claim to be 100% correct
ETA 5/8/20: I've been advised that the result was correct, it was the initial interpretation that needed to be withdrawn
Meta? I'd say so!

User avatar
dyqik
Light of Blast
Posts: 5223
Joined: Wed Sep 25, 2019 4:19 pm
Location: Masshole
Contact:

Re: The Death Of Fossil Fuels

Post by dyqik » Sat Apr 23, 2022 10:08 pm

jimbob wrote:
Sat Apr 23, 2022 9:35 pm
dyqik wrote:
Sat Apr 23, 2022 8:13 pm
Gfamily wrote:
Sat Apr 23, 2022 7:52 pm

Yes, obviously; but 7x the fuel volume (even if not adding fuel weight) has to go somewhere. So either there will be longer bodies of the same cross section (7x longer?), or wider bodies.
Or the need for a significant reduction in payload volume.
Does that affect the actual limits on capacity?
If you have wider bodies, then you're affecting the air resistance. Which is important at the start.
The question is whether you need wider bodies, and whether that makes a big difference to the coefficient of drag.

Remember, fuel isn't only stored in the bodies right now, but also in the wings. And a wider body doesn't necessarily make a huge difference to the drag, which is dominated by wings etc. Not having fuel tanks in the wings may open up a bit more design space.

User avatar
dyqik
Light of Blast
Posts: 5223
Joined: Wed Sep 25, 2019 4:19 pm
Location: Masshole
Contact:

Re: The Death Of Fossil Fuels

Post by dyqik » Sat Apr 23, 2022 10:15 pm

Gfamily wrote:
Sat Apr 23, 2022 9:46 pm
The A320 has a cargo capacity of about 37m^3
Replacing the 27,000 litres of fuel capacity with ~190,000 litres of LH is going to take all of that and more.

ETA Clearly, it's not going to be a straight swap, but as a back of the envelope calculation, I don't think it's too far out to say "it's not going to make a negligible difference"
You've missed the factor of two improvement in efficiency of fuel cells vs combustion engines there - it's more like 100k liters of LH2 needed.

That takes up an additional 7m of fuselage length (cabin width is 3.7m), which is enough that you'd not just add it all while keeping the same diameter of the body.

It's not simple to add, but it's certainly not non-viable to include in a design, particularly since it doesn't weigh very much.

User avatar
shpalman
Princess POW
Posts: 6879
Joined: Mon Nov 11, 2019 12:53 pm
Location: One step beyond

Re: The Death Of Fossil Fuels

Post by shpalman » Sat Apr 23, 2022 10:32 pm

jimbob wrote:
Sat Apr 23, 2022 9:35 pm
dyqik wrote:
Sat Apr 23, 2022 8:13 pm
Gfamily wrote:
Sat Apr 23, 2022 7:52 pm

Yes, obviously; but 7x the fuel volume (even if not adding fuel weight) has to go somewhere. So either there will be longer bodies of the same cross section (7x longer?), or wider bodies.
Or the need for a significant reduction in payload volume.
Does that affect the actual limits on capacity?
If you have wider bodies, then you're affecting the air resistance. Which is important at the start.
https://en.wikipedia.org/wiki/Airbus_Beluga
molto tricky

User avatar
Martin_B
Dorkwood
Posts: 1251
Joined: Mon Nov 11, 2019 1:20 pm
Location: Perth, WA

Re: The Death Of Fossil Fuels

Post by Martin_B » Sat Apr 23, 2022 11:30 pm

dyqik wrote:
Sat Apr 23, 2022 10:15 pm
Gfamily wrote:
Sat Apr 23, 2022 9:46 pm
The A320 has a cargo capacity of about 37m^3
Replacing the 27,000 litres of fuel capacity with ~190,000 litres of LH is going to take all of that and more.

ETA Clearly, it's not going to be a straight swap, but as a back of the envelope calculation, I don't think it's too far out to say "it's not going to make a negligible difference"
You've missed the factor of two improvement in efficiency of fuel cells vs combustion engines there - it's more like 100k liters of LH2 needed.

That takes up an additional 7m of fuselage length (cabin width is 3.7m), which is enough that you'd not just add it all while keeping the same diameter of the body.

It's not simple to add, but it's certainly not non-viable to include in a design, particularly since it doesn't weigh very much.
Adding the fuel in the fuselage body might also make the aircraft handle significantly differently at take-off and landing (ie, 'full' and 'empty'). Changing the centre of gravity of the plane can make huge changes to trims required.

Maybe the computer systems can handle that these days such that the pilots won't notice the difference, and I doubt that the answer will be as simple as adding a 7m fuel tank at the back of the fuselage, but any sort of long, thin fuel tank stretching along the fuselage to counter centre of gravity changes will negate savings in fuel tank weight, and could add access and safety issues.
"My interest is in the future, because I'm going to spend the rest of my life there"

User avatar
Gfamily
Stummy Beige
Posts: 3811
Joined: Mon Nov 11, 2019 1:00 pm
Location: NW England

Re: The Death Of Fossil Fuels

Post by Gfamily » Sat Apr 23, 2022 11:39 pm

The A321 is about 7 metres longer than the A320, so it's not too much of a stretch to make it work.
My avatar was a scientific result that was later found to be 'mistaken' - I rarely claim to be 100% correct
ETA 5/8/20: I've been advised that the result was correct, it was the initial interpretation that needed to be withdrawn
Meta? I'd say so!

User avatar
Martin_B
Dorkwood
Posts: 1251
Joined: Mon Nov 11, 2019 1:20 pm
Location: Perth, WA

Re: The Death Of Fossil Fuels

Post by Martin_B » Sat Apr 23, 2022 11:55 pm

Gfamily wrote:
Sat Apr 23, 2022 11:39 pm
The A321 is about 7 metres longer than the A320, so it's not too much of a stretch to make it work.
Elongating the fuselage isn't the bit I had concerns about. Both the A320 & A321 will have a centre of gravity somewhere around the wings and it won't change significantly between loaded and unloaded conditions.
"My interest is in the future, because I'm going to spend the rest of my life there"

Post Reply