Methane fuel physical plant details

[Nefrums]

The Martian dust storms can be a problem for solar panels. But I still think that thin film solar panels are the way to go.

You just have to figure out a way of getting the dust of them.

I doubt that the storms can cause any damage or even move the panels. As Martian storms has half the wind speed of Earth storms, and combined with the 1% pressure, that means they only have 0,5% of the power compared to earth storms.

Edited January 24, 2018 by Nefrums

[Green Baron]

I will have my triumph the day Wikipedia falters.

Yeah, 70 Watt average, 200 peak, and yes, panels on earth get this (surface, not space), for my area (28° North, >300 days sunshine/year) that's conservative these days. ISS is old stuff, no valid reference. Cables have only little influence if the right diameter for the temperature and current is chosen. Banana, same (or more) applies to other sources. Conversion from 18-24V or so to whatever is needed the other end doesn't swallow much.

We can make this pretty easy: a (tracking) panel with two square meters, sunshine all around the year (assuming no or few clouds on Mars), near the equator, that's 12.5 hours each day 600*0.3*12.5 = 2.5KW/day average, 5KW peak. 300.000 of them will produce 54MW. Walla.

Oh, i combobulated m² and pieces in my post farther up. I am as sorry as necessary :-)

[PB666]

1 minute ago, Nefrums said:

The Martian dust storms can be a problem for solar panels. But I still think that thin film solar panels are the way to go.

You just have to figure out a way of getting the dust of them.

I doubt that the storms can cause any damage or even move the panels. As Martian storms has half the wind speed of Earth storms, and combined with the 1% pressure, that means they only have 0,5% of the power compared to earth storms.

The thin films are not electronically robust enough to survive a solar storm. You could not really tilt them, without adding alot of mass.

Solar storms that hit mars are not an issue of mass flow, they are an issue of charge flow. If you can imagine a wave of charged particles hitting mars at an oblique angle the charge that accumulate on one side of the panel could be in the 10s of 1000s of volts relative to the other side. Since Mars has no van Allen belts there is no way for the electric charges to interact (force particles around) to neutralize or to dissipate the magnetic field. Then the problem  is what in the atmosphere will slow down these charged particles. The electrons will avoid the electric dipoles of CO2 and the delta positive is shielded by the dipole, the positively charged proton is very small.
If we recall the de Broglie hypothesis that every particle has a wavelength according to its inverse momentum.

Then the wavelength of a proton as it travels is much smaller than an electron, its less likely to collide. Its going to continue traveling thorough the atmosphere of Mars until it has something magnetic or negatively charged to interact with. https://en.wikipedia.org/wiki/Geiger–Marsden_experiment shows that interaction, even with alpha particles for a plane of gold molecules is very small.

Again don't think of Mars atmosphere in total of behaving like Earths. Earths atmosphere is 3000 times denser, it protected by a magnetic field and van allen belts.  

[Green Baron]

13 minutes ago, Nefrums said:

I doubt that the storms can cause any damage or even move the panels.

Nope. Winds here can reach 100km/h in gusts, no problem. Wind pressure on Mars is no problem at all. But someone needs to dust the panels or they need a dust repelling coating. Since they are angled it should work, but i do not know !

[PB666]

1 minute ago, Green Baron said:

I will have my triumph the day Wikipedia falters.

Yeah, 70 Watt average, 200 peak, and yes, panels on earth get this (surface, not space), for my area (28° North, >300 days sunshine/year) that's conservative these days. ISS is old stuff, no valid reference. Cables have only little influence if the right diameter for the temperature and current is chosen. Banana, same (or more) applies to other sources. Conversion from 18-24V or so to whatever is needed the other end doesn't swallow much.

We can make this pretty easy: a (tracking) panel with two square meters, sunshine all around the year (assuming no or few clouds on Mars), near the equator, that's 12.5 hours each day 600*0.3*12.5 = 2.5KW/day average, 5KW peak. 300.000 of them will produce 54MW. Walla.

Oh, i combobulated m² and pieces in my post farther up. I am as sorry as necessary :-)

You are blowing off all the other mass you need, essentially. Even I am being too too generous, the power production per kilogram in any panel, today, ready to ship and be stationed on Mars has a far lower KW/mass.

[Green Baron]

6 minutes ago, PB666 said:

The thin films are not electronically robust enough to survive a solar storm. You could not really tilt them, without adding alot of mass.

Nah. See panels on the Juno probe. They are exposed all the time and degrade 10-15% from radiation over the decades, that's all.

4 minutes ago, PB666 said:

You are blowing off all the other mass you need, essentially. Even I am being too too generous, the power production per kilogram in any panel, today, ready to ship and be stationed on Mars has a far lower KW/mass.

There isn't much, almost nothing. No shielding, transformer, cables. Eventually tracking stuff. But what's a small engine and a ball rest ? Less then with a nuclear thing probably. That's what makes them so interesting for space, even out to Jupiter these days.

Edit: oh, batteries of course ... that's a (big) point. But a nuclear thing would need outage buffer at least ... clear ... much smaller ...

Edited January 24, 2018 by Green Baron

[PB666]

2 minutes ago, Green Baron said:

Nah. See panels on the Juno probe. They are exposed all the time and degrade from radiation over the decades, that's all.

You pat yourself on the back too soon, Juno's panels weight 340 kg  and they are 3 x 2.7 x 8.9 or 72.09. Therefore they weigh 4.7 kg per meter. Again I am being very generous about power per unit weight for Mars.

[Green Baron]

Solar is the best available technology for anything power. The "kilopower" unit has moving parts, a limited lifetime, highly toxic ingredients, operates at high temperatures, needs all kinds of shielding, weighs 600kg (that is almost triple specific mass to power ratio compared to solar panels !) according to this.

I must admit, i doubt the mass, but there it stands ... is there something newer about this ? But if its true this is the time to give up the weight argument ....

Edited January 24, 2018 by Green Baron

[PB666]

33 minutes ago, Green Baron said:

Solar is the best available technology for anything power. The "kilopower" unit has moving parts, a limited lifetime, highly toxic ingredients, operates at high temperatures, needs all kinds of shielding, weighs 600kg (that is almost triple specific mass to power ratio compared to solar panels !) according to this.

I must admit, i doubt the mass, but there it stands ... is there something newer about this ? But if its true this is the time to give up the weight argument ....

It is th best but its not suitable for everywhere on Mars. The less suitable the spot, the more infrastructure that will need to be added.
 

Lets give a example, Suppose NASA spots a great place to put a space base next to a crater with Frozen water at the bottom. Say 65'N, IOW it can get sunshine all year round, just barely in the winter months. The facility would be close to the bottom of the crater, were are the panels going to be. They will be at the top, and during the winter those panels will be facing the horizon, which means panels on the surface are not suitable, on the bright side dust will not be a problem, on the bad side any solar wind that hits the panels that come through the thinnest part of the atmosphere will basically exert their full electric force on the panel. Again such a panel would need to be electrically transformed and a long two-wire conductor will have to go from that site to the water extraction site. So we abandon all sites that are above say 45 degrees N that are close to water. Since the energy flow is slow in the time of the year you need the most heat then you need NTGs or RTGs to generate power during the off period (or move the denizens to a more suitable spot).

So if you go to the equator, how far down do you dig before you need to hit water, again that has a different weight cost. If water is not close to the surface it needs to be elevated (mah) and then it needs to be purified (kCal/mole cost).

Finding water in space is alot easier than dealing with the water limits on Mars. I mean you could dig a very deep pit on Mars equator and hurl directed blobs of Ice into the pit. That is a solution.

 

 

Edited January 24, 2018 by PB666

[Green Baron]

2 hours ago, PB666 said:

It is th best but its not suitable for everywhere on Mars.

Absolutely, one head and one a..., higher/lower latitudes than 50° it is not the first or even second choice.

Another thing: the initial cartload for solar power generation would be a big one, but replacement/expansion/discontinuation/disposal is much easier than the nuclear stuff. I think we can expect batteries/storage to become much denser than today, especially in the course of electric cars and traffic.

Also, i am high tech freak, technology from the last millennium just doesn't sound and feel right :-)

[PB666]

1 minute ago, Green Baron said:

Absolutely, one head and one a..., higher/lower latitudes than 50° it is not the first or even second choice.

Another thing: the initial cartload for solar power generation would be a big one, but replacement/expansion/discontinuation/disposal is much easier than the nuclear stuff. I think we can expect batteries/storage to become much denser than today, especially in the course of electric cars and traffic.

Also, i am high tech freak, technology from the last millennium just doesn't sound and feel right :-)

Even at 70'N it can be useful.

There is no doubt that cutting edge technology can be useful, but for most people the technology they are familiar with was often invented decades ago. The durable glass on the smartphone was invented about 2 decades before it was used for some completely different application (something like durable windows for space craft) and was never seriously used in that application. When I was getting out of college people were talking about bucky-balls and this kind of thing. Diffraction gratings for spectral analysis was invented (I don't even know 1920s) but were never seriously used for bulk photospectronomy until 1980s. Just because something is the latest tech does not mean it has been reworked for a highly specified usage. For example, I would not take any current computer into space (having just built one), the basic problem is that for instance, the demands on power supplies are much more finicky than past computers. There are several computers I owned I never replaced a power supply, never even thought of replacing a power supply, I have 40 year old pieces of equipment that I threw away that still had the original power supplies working in them. I have computers that are 6 months old and are on their 3rd power supply. This is amazing because I tend to chose processors and video on the performance inflection point (generally means 4 or 5 years old relative to peak performance). The panels on the ISS are massive, each Bus is something like 14,000 kg. We don't even consider the power per unit weight I once calculated it to 20kg per sq. meter or something like that. But of course none of them have failed, the ISS, of course is over built, but its not overbuild by a magnitude. This means that in order to get the power/weight issue down some very huge near future change needs to occur. Yes we can use carbon fiber (weight is 1/3rd) yes we can use superconducting materials, sure its possible to get more efficient. But there also tradeoffs.

If you are at a high elevation and at 70'C you are pretty much above any scattering layer, you have very little atmospheric scattering (except in the UV spectrum) so that you can horizontally look through the atmosphere with less scattering than on Earth. The problem is that as you get further north during part of the year you have great sun, but during part of the year you have no sun or only a few hours per day.

In terms of panel disposal, this is going to be a thing on Mars were absolutely you have to recycle the panels. There is no situation on Mars were hunting for rare-earth minerals will be profitable or feasible. But on the other hand, since bulk panels are flat, reasonable density, they can be shipped and while they are being shipped they don't loose performance, and given that they are flat they can be made into basically a giant aero-foil and landed on mars with little waste. So if we had a ION powered space tug, we could not to expensively ship  lots of panels to Mars. BFR however is not a space tug. BFR is to tugging what Fed-Ex is to bulk-materials shipping.

Remember that the most popular electric cars also have chemical engines, they are still using basically 1930s battery technology. A hybrid is much more about the drive system (engine off time) than it is about the battery. The materials they are discovering today, for example graphene based materials, 20 or 30 years, much less if the gov't says we want you to apply these things into space technologies now.

 

[kerbiloid]

So, what's the conclusion about the solar panels?

Spoiler

(Though it originally was a methane production thread, but who cares).

How much would weight mass the modern, hi-tech, vandal-proof,  wiki-proof solar panels for Mars to get 1 kW?
How long would they live?

Edited January 25, 2018 by kerbiloid

[Green Baron]

2 hours ago, kerbiloid said:

So, what's the conclusion about the solar panels?

  Reveal hidden contents

(Though it originally was a methane production thread, but who cares).

How much would weight mass the modern, hi-tech, vandal-proof,  wiki-proof solar panels for Mars to get 1 kW?
How long would they live?

A rugged one aluminium framed covered with glass and backed with a plastic plate for use in the backyard or on the rooftop weighs around 15-20kg. It is ~90*180cm. The weight mass can easily be halved for space app. At noon it will produce around 583*0.3*0,9*1.8 Watt, at midnight 0. 0.3 is the assumed efficiency.

I assume your stuff needs 1kW all around the clock, that is 25kWh. Half of that must be provided by the battery which must be charged. Batteries should not discharge fully, so multiply again by 2, but depends on kind of battery(*), so 25kWh.

Size calculation for the battery bank is trivial if you have the voltage (let's say 48V because the higher the better in terms of line loss), so it boils down to dividing the 25kWh by 48V which gives us a bank of *thispchasnocalculatorinstallederror* battary capacity in Ah.

Pls. double check with one of the many online calculators. Keep in mind that the generation in them is for earth (1kW/m², not 0.583).

(*) lead based batteries should not discharge lower than 50%, Li-Ion ones 70% ?

 

Edit: state of the art consumer type batteries: according to a quick search a car battery (Li-ion) of 100kWh weighs around 600kg. To charge it fully from 0 and at the same time provide 100kWh one would need ~800 solar panels with a mass of 12tons. If you design your stuff to use 48V (should be done on earth anyway !) a few cables and plugs are all else you need. All easily scaleable and maintainable, and with the weight of the panels, i think there is a lot of leeway for space application, so we can get down to 6tons for the panels, 600kg for the battery, a few hundred kilo for cables and plugs.

Edited January 25, 2018 by Green Baron

[FleshJeb]

15 hours ago, Green Baron said:

I assume your stuff needs 1kW all around the clock

FYI, the paper I linked only has the ISRU process running 12 hours a day.

On 1/24/2018 at 3:02 PM, PB666 said:

I have computers that are 6 months old and are on their 3rd power supply.

That's a component quality problem. This company had a fantastic reputation back when I was into computers: https://www.pcpowerandcooling.com/

[Green Baron]

10 minutes ago, FleshJeb said:

FYI, the paper I linked only has the ISRU process running 12 hours a day.

 

So that would be a solar power friendly setup then, or a battery saver ... :-)