Crops under solar panels can be a win-win

Of course I know it. But none of that means that it can't used. The same objections apply to liquid oxygen, and your incapacity to appreciate this isn't clever.

Liquid hydrogen is a lot colder than liquid oxygen, but your prediction that it will never get a general aviation certificate may not be all that useful.

If liquid hydrogen is the fuel that aviation industry needs to stay in the mass market, they will work out how to live with the associated difficulties.

Neither of us owns a certified crystal ball, and there's always the possibility that very high speed trains (possibly running in evacuated pipes or tunnels) may eat the aviation industry's mass market.

Clifford Heath wrote in news:7pHcF.99414$ snipped-for-privacy@fx27.iad:

Yes, and do not those boosters rely on eject after use SRBs for initial lift segment? The part that returns is expensive. Expensive to make into a returnable, when disposable is not that much more. But then there is that carbon footprint litterbug thing.

I do not think I fully get the returnablr booster thing. That has to add a lot of weight to it and detract from total payload capacity.

Bill Sloman wrote in news: snipped-for-privacy@googlegroups.com:

The rocket motors are more difficult to design and use, because the liquid hydrogen gets boiled (evaporated) into gaseous form for mixing with also evaporated liquid Oxygen before making it to the "carburator" and subsequent engine nozzle. The liquid form is simply to allow for more storage of a greater than when used density fuel element. Also single element "fuels" have no residue to worry about.

Liquid elements discussed here "boil" at a very low temperature with respect to normal lay person human interpretation. I guess 'evaporation' is the correct term. I essentially mean that before any "fuel" hits the engine nozzle, it is 'converted' from liquid phase to gas phase.

The big Saturn V engines which went on to be those used also in the space shuttle had evaporation coils encircling the entire engine nozzle.

Except that our tape-out cost $2M (c. 2005).

Yuppie greenies standing around and pointing at things. Not an actual farmer in overalls in sight.

Why just two wins? Why not win-win-win? Alternate rows of solar cells, organic quinoa, and Tesla assembly lines.

The latest issue of Aviation Week discusses some experimental hydrogen fuel-cell airplanes. Boiloff of cryo hydrogen is a severe limitation on range. Looks like 10,000 PSI room-temp gas might work, if the fuel cell cost and weight can be improved maybe 5:1.

The best way to store hydrogen is to stick it to carbon.

Boiloff limits hydrogen fuel-cell flights to something like 2 hours max. A rocket uses up all its 1st stage fuel supply in minutes.

And rockets are expensive.

Cool!

Have you connected with any of the vintage/resto, homebrew or emulator communities? If you still have some code or tools floating around that's since lapsed out of NDA it could prove very helpful to some. :)

Tim

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s-can-be-a-win-win/

for the amount of food produced the solar panels stay cooler improving the ir electrical production. True win-win.

ything is an improvement. It is not a general recommendation.

es to run irrigation pumps, and they really want to be using drip irrigatio n in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff doesn 't do well in shade. Notice they didn't mention any of the economics, but t he crummy vegetable crop isn't going to make up for the loss of revenue due to greatly reduced panel density.

ways. They have HUGE problems. Here is a story about their plastics proble m:

illion-plastic-problem

unsustainable.

There really aren't enough private planes to create a problem, but interna tional tourism probably has to go.

be true.

d hydrogen fuel - rather lower energy density than liquid hydrocarbons - mi ght save the tourist industry, but it would take a while and a great deal o f expensive development.

uel. You can make the tanks well-enough insulated that the boil-off rate is tolerable.

ing for take-off, but "bulbous" does envisage thicker insulation than you'd choose for a rocket.

Perhaps more costly than other liquid fuels. "Inordinately" is a value judg ement, and ingenious design has a way of making problems less "inordinate" than they might seem at first sight.

Thicker or better insulation is always a possibility.

Or nitrogen. Liquid ammonia gets shipped around in truckloads.

ote:

ote:

ls-can-be-a-win-win/

r for the amount of food produced the solar panels stay cooler improving th eir electrical production. True win-win.

nything is an improvement. It is not a general recommendation.

kes to run irrigation pumps, and they really want to be using drip irrigati on in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff does n't do well in shade. Notice they didn't mention any of the economics, but the crummy vegetable crop isn't going to make up for the loss of revenue du e to greatly reduced panel density.

y ways. They have HUGE problems. Here is a story about their plastics probl em:

billion-plastic-problem

unsustainable.

. There really aren't enough private planes to create a problem, but intern ational tourism probably has to go.

be true.

id hydrogen fuel - rather lower energy density than liquid hydrocarbons - m ight save the tourist industry, but it would take a while and a great deal of expensive development.

el. You can make the tanks well-enough insulated that the boil-off rate is tolerable.

ng for take-off, but "bulbous" does envisage thicker insulation than you'd choose for a rocket.

Boil-off limited a particular liquid hydrogen fuel-cell flight to something like two hours. The quality and thickness of the insulation on the liquid hydrogen tank is a design feature.

Most of the discussions of liquid hydrogen powered long range aircraft talk about bulbous designs to make room for bigger fuel tanks with thicker insu lation than the current generation of slimline aircraft can accommodate.

So are aircraft. Of course we build more aircraft so there's more economy o f scale.

ote:

ls-can-be-a-win-win/

r for the amount of food produced the solar panels stay cooler improving th eir electrical production. True win-win.

nything is an improvement. It is not a general recommendation.

kes to run irrigation pumps, and they really want to be using drip irrigati on in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff does n't do well in shade. Notice they didn't mention any of the economics, but the crummy vegetable crop isn't going to make up for the loss of revenue du e to greatly reduced panel density.

y ways. They have HUGE problems. Here is a story about their plastics probl em:

billion-plastic-problem

unsustainable.

. There really aren't enough private planes to create a problem, but intern ational tourism probably has to go.

be true.

id hydrogen fuel - rather lower energy density than liquid hydrocarbons - m ight save the tourist industry, but it would take a while and a great deal of expensive development.

fuel.

Are you sure about that? From your cite,

"Hydrogen embrittlement (HE) also known as hydrogen assisted cracking (HAC) and hydrogen-induced cracking (HIC), describes the embrittling of metal af ter being exposed to hydrogen. It is a complex process that is not complete ly understood because of the variety of mechanisms that can lead to embritt lement."

e:

ote:

ls-can-be-a-win-win/

r for the amount of food produced the solar panels stay cooler improving th eir electrical production. True win-win.

nything is an improvement. It is not a general recommendation.

kes to run irrigation pumps, and they really want to be using drip irrigati on in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff does n't do well in shade. Notice they didn't mention any of the economics, but the crummy vegetable crop isn't going to make up for the loss of revenue du e to greatly reduced panel density.

y ways. They have HUGE problems. Here is a story about their plastics probl em:

billion-plastic-problem

unsustainable.

. There really aren't enough private planes to create a problem, but intern ational tourism probably has to go.

be true.

id hydrogen fuel - rather lower energy density than liquid hydrocarbons - m ight save the tourist industry, but it would take a while and a great deal of expensive development.

fuel.

Why is that relevant? The limitation to reusing rockets is the control to allow them to land and be recovered.

How many were reusing rockets of any type until Musk did it?

Someone said it's not practical to use Hydrogen fuel, then someone else poi nted out those examples were single use, but there is nothing inherent in h ydrogen fuel that makes a reusable rocket impractical.

Or is there something about this you aren't telling?

rote:

te:

s-can-be-a-win-win/

for the amount of food produced the solar panels stay cooler improving the ir electrical production. True win-win.

ything is an improvement. It is not a general recommendation.

es to run irrigation pumps, and they really want to be using drip irrigatio n in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff doesn 't do well in shade. Notice they didn't mention any of the economics, but t he crummy vegetable crop isn't going to make up for the loss of revenue due to greatly reduced panel density.

ways. They have HUGE problems. Here is a story about their plastics proble m:

illion-plastic-problem

unsustainable.

There really aren't enough private planes to create a problem, but interna tional tourism probably has to go.

be true.

d hydrogen fuel - rather lower energy density than liquid hydrocarbons - mi ght save the tourist industry, but it would take a while and a great deal o f expensive development.

uel. You can make the tanks well-enough insulated that the boil-off rate is tolerable.

ing for take-off, but "bulbous" does envisage thicker insulation than you'd choose for a rocket.

The trouble with that is returning the carbon so it can be reused. It tend s to get into the exhaust stream with the obvious issues that creates.

Much easier to return your electrons to have them rejuvenated electrically.

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t fuel.

C) and hydrogen-induced cracking (HIC), describes the embrittling of metal after being exposed to hydrogen. It is a complex process that is not comple tely understood because of the variety of mechanisms that can lead to embri ttlement."

Of course I'm not sure. On the other hand, we don't "completely understand" a whole lot of processes that we can manage perfectly adequately.

The Australian hydrogen lobby hopes to make a lot of money by shipping tank er loads of liquid hydrogen from Australia to Japan and South Korea.

That does imply that some people with money are fairly confident that the t ankers won't start breaking in half before they get to their destinations.

Of course the first few super-sized oil tankers did break in half from time to time, so their confidence isn't necessarily well-founded.

rote:

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ket fuel.

ns.

HAC) and hydrogen-induced cracking (HIC), describes the embrittling of meta l after being exposed to hydrogen. It is a complex process that is not comp letely understood because of the variety of mechanisms that can lead to emb rittlement."

d" a whole lot of processes that we can manage perfectly adequately.

Ok, so if you aren't sure, but you still think we should listen to your arg ument?

nker loads of liquid hydrogen from Australia to Japan and South Korea.

tankers won't start breaking in half before they get to their destinations .

When do they think they will break in half?

me to time, so their confidence isn't necessarily well-founded.

You seem to be arguing against yourself.

y to

ocket fuel.

ions.

(HAC) and hydrogen-induced cracking (HIC), describes the embrittling of me tal after being exposed to hydrogen. It is a complex process that is not co mpletely understood because of the variety of mechanisms that can lead to e mbrittlement."

and" a whole lot of processes that we can manage perfectly adequately.

rgument?

tanker loads of liquid hydrogen from Australia to Japan and South Korea.

he tankers won't start breaking in half before they get to their destinatio ns.

Probably not at all.

time to time, so their confidence isn't necessarily well-founded.

I'm trying to be realistic, rather than dogmatic.

How much do you pay for a paper match and a wrap of aluminum foil? Someone has been overcharging you very badly.

For aircraft, there's AIR available, the 'first stage fuel' in an expensive space rocket is burned so quckly because that's how you avoid lifting (among other things) a lot of liquid oxygen. The economics of space rockets don't apply to aircraft.

Those reusable stages have mainly been the first stage, i.e. running in a high atmospheric pressure, in which the trust drops compared to vacuum. In such environments it makes sense to use exhaust gases with higher molecular weight.

In addition, the LH2 would require huge tanks. Think about how huge the first stage of Saturn V have been, if the fuel had been LH2 instead of kerosine. On the Shuttle, LH2 takes out the main part of the ET and still you need those SRBs as the first stage.

On Sunday, September 8, 2019 at 6:17:35 AM UTC-4, snipped-for-privacy@downunder.com wr ote:

rote:

te:

anels-can-be-a-win-win/

ater for the amount of food produced the solar panels stay cooler improving their electrical production. True win-win.

y anything is an improvement. It is not a general recommendation.

takes to run irrigation pumps, and they really want to be using drip irrig ation in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff d oesn't do well in shade. Notice they didn't mention any of the economics, b ut the crummy vegetable crop isn't going to make up for the loss of revenue due to greatly reduced panel density.

many ways. They have HUGE problems. Here is a story about their plastics pr oblem:

ing unsustainable.

the

lem. There really aren't enough private planes to create a problem, but int ernational tourism probably has to go.

to be true.

iquid hydrogen fuel - rather lower energy density than liquid hydrocarbons

- might save the tourist industry, but it would take a while and a great de al of expensive development.

et fuel.

to allow them to land and be recovered.

pointed out those examples were single use, but there is nothing inherent i n hydrogen fuel that makes a reusable rocket impractical.

ET?

I don't know why people find typing to be so difficult.