An energy solution for Mars...

louis · 2015-05-13 16:12:35

This system for generating electricity using solar reflectors and a Stirling engine sounds like it could be a great solution for generation on Mars:-

http://www.theguardian.com/environment/ … ity-system

Using 3D printers coupled with basic steel production - I think a small Mars colony (numbered in tens of people) could manufacture the solar reflectors, which look they consitute the bulk of the system. They might even be able to produce stirling engines as well.

GW Johnson · 2015-05-14 14:05:04

Dunno, Louis, might work pretty good. It'll need much bigger reflectors, since the solar flux is about half out at Mars. Not as cloudy as here (excepting dust storms), which is good. Losses to the more extreme cold are bad, but the more extreme cold may make the engine more efficient in its cooling phase. 34% efficient ain't nothing to sneeze at. Giant Rankine-cycle (steam turbine) power plants here are at best about 40-something-% efficient. Size plays a role, too. What's in ships is 30-something-% efficient.

I'd be awfully careful about pinning all hopes on 3-D printing. I know they can print metal parts now, but the structural properties are no better than sintered metal forms, which are really, really lousy compared to real forged forms. Doesn't matter what metal you talk about. I'd never make a tool like a wrench, or especially a pressure vessel, by 3-D printing. Not anytime soon, meaning next several decades.

GW

SpaceNut · 2015-05-14 17:21:21

Since the critical partis the Stirling engine that I would ship with the plumbing but possibly from waste metals and packaging from the trip out to Mars and if we bring it to the surface we have what we would need for making the reflector...Also with power creation you need efficient storage (see other topic) as well as conversion back to what is a useful form of power.

louis · 2015-05-15 03:31:00

GW Johnson wrote:

Dunno, Louis, might work pretty good. It'll need much bigger reflectors, since the solar flux is about half out at Mars. Not as cloudy as here (excepting dust storms), which is good. Losses to the more extreme cold are bad, but the more extreme cold may make the engine more efficient in its cooling phase. 34% efficient ain't nothing to sneeze at. Giant Rankine-cycle (steam turbine) power plants here are at best about 40-something-% efficient. Size plays a role, too. What's in ships is 30-something-% efficient.
I'd be awfully careful about pinning all hopes on 3-D printing. I know they can print metal parts now, but the structural properties are no better than sintered metal forms, which are really, really lousy compared to real forged forms. Doesn't matter what metal you talk about. I'd never make a tool like a wrench, or especially a pressure vessel, by 3-D printing. Not anytime soon, meaning next several decades.
GW

Not sure it needs bigger reflectors. The system referenced produces enough power for 23 homes...you simply get maybe half the power on Mars - enough for the equivalent of 11.5 homes!

Well perhaps the 3D printer will just give the mould which can then be used to shape the metal.

Just been reading up on the manufacture of solar reflectors.

http://en.wikipedia.org/wiki/Solar_mirr … _substrate

Protective glass should not be a problem on Mars. I also note that Mars meteorites found on Earth have contained aluminium so one would hope that deposits of aluminium would allow for construction of the reflectors.

Looks like we know aluminium is definitely there:

http://www.jpl.nasa.gov/news/news.php?release=2014-201

SpaceNut · 2015-12-10 11:09:05

bump

Antius · 2015-12-10 12:41:19

Flat plate collectors would be sufficient relatively close to the equator. No need for tracking or even glass covers. You don't need to produce hot water, only warm enough to overcome the latent heat of melting of water or brine. So that's anything above -20C. You can then use the same panels during Martian night time as heat sinks. The temperatures are cold enough to bring CO2 down to liquid conditions at a pressure of 5.1 bar. So a CO2 vapour engine will work fine using flat panels. Earth doesn't get the right temperature ranges to make this workable, but Mars does.

louis · 2015-12-10 18:12:04

Seems like metal powders - iron being perfect -can serve as fuels.

http://m.phys.org/news/2015-12-metal-po … fuels.html

Not sure if we've focused on this before.

GW Johnson · 2015-12-10 18:58:24

Well, when your combustion products are created as solids (or liquids) it is very difficult to get any actual energy production out of your thermodynamic cycle, regardless of what the energy balance might say. Condensed phases DO NOT expand, only gas phase stuff does that.

Only gas phases allow expansion from high pressure to low, that does useful work. That, in and of itself, is therefore a very fundamental objection to some of the things I've seen proposed. That includes silane burning with CO2. Your products are SiO2 and C, both solids at any reasonable conditions, and SiO2 is still liquid at some very unreasonable conditions.

The other objection is very practical. If your exhaust products include more-than-utterly-trivial solid or liquid phases, just how do you expect either a piston or a turbine system to function without destroying itself? These kinds of things destroy seals and wear out all other imaginable structures, at very short time scales.

And, I defy you to name a system that generates energy in useful forms, that is not based upon hardware that is either piston or turbine.

The only concept I ever heard that meets that last criterion is MHD, but those kinds of condensed-phase exhaust products slag-up the flow passage (changing its geometry significantly), and coat-over any energy-production features (rendering them ineffective). So, even MHD won't work with condensed phases present.

GW

SpaceNut · 2015-12-10 22:12:32

Antius wrote:

Flat plate collectors would be sufficient relatively close to the equator. No need for tracking or even glass covers. You don't need to produce hot water, only warm enough to overcome the latent heat of melting of water or brine. So that's anything above -20C. You can then use the same panels during Martian night time as heat sinks. The temperatures are cold enough to bring CO2 down to liquid conditions at a pressure of 5.1 bar. So a CO2 vapour engine will work fine using flat panels. Earth doesn't get the right temperature ranges to make this workable, but Mars does.

interesting a temperature differential engine.... which is the makings of a Stirling engine
https://en.wikipedia.org/wiki/Stirling_engine
http://www3.nd.edu/~me463d18/Files/Dere … rmance.pdf

http://cmex.ihmc.us/data/catalog/Surfac … tTemp.html

Antius · 2015-12-11 06:47:06

GW Johnson wrote:

Well, when your combustion products are created as solids (or liquids) it is very difficult to get any actual energy production out of your thermodynamic cycle, regardless of what the energy balance might say. Condensed phases DO NOT expand, only gas phase stuff does that.
Only gas phases allow expansion from high pressure to low, that does useful work. That, in and of itself, is therefore a very fundamental objection to some of the things I've seen proposed. That includes silane burning with CO2. Your products are SiO2 and C, both solids at any reasonable conditions, and SiO2 is still liquid at some very unreasonable conditions.
The other objection is very practical. If your exhaust products include more-than-utterly-trivial solid or liquid phases, just how do you expect either a piston or a turbine system to function without destroying itself? These kinds of things destroy seals and wear out all other imaginable structures, at very short time scales.
And, I defy you to name a system that generates energy in useful forms, that is not based upon hardware that is either piston or turbine.
The only concept I ever heard that meets that last criterion is MHD, but those kinds of condensed-phase exhaust products slag-up the flow passage (changing its geometry significantly), and coat-over any energy-production features (rendering them ineffective). So, even MHD won't work with condensed phases present.
GW

From what you have described, an external combustion device is probably the only thing that would work, aka a boiler.

My understanding of an MHD was that it is basically a hollow tube with magnets and coils behind the walls. If the exhaust products are basically reducing (i.e. carbon, CO and SiO2) then a smooth stainless steel surface might be polished to an extent that adhesion for solid combustion products is exceptionally poor. If the dynamic pressure of the gases passing through is sufficient, then perhaps it will avoid fowling up. But then again, tiny solid particles tend to carry electric charge which makes them stick to everything. I wouldn't want to bet my life on riding a silane fuelled ram jet at 1km/s through the Martian atmosphere. In a rocket engine, any deposits on the wall could cause burnout by disrupting the boundary layer. So from what you have described this won't be very useful for a mobile device unless it can be run at chamber pressures that are low enough to make the burn-out problem survivable. For a boiler, any heat transfer surfaces would need to be brushed down after each and every operation. That doesn't sound very efficient.

The solution might be to carry the fuel in cartridges that capture the solid products. You just dump the whole cartridge after use. But again, that seems to ruin the economics of the concept.

Last edited by Antius (2015-12-11 06:50:12)

Antius · 2015-12-11 10:35:56

SpaceNut wrote:

Antius wrote:
Flat plate collectors would be sufficient relatively close to the equator. No need for tracking or even glass covers. You don't need to produce hot water, only warm enough to overcome the latent heat of melting of water or brine. So that's anything above -20C. You can then use the same panels during Martian night time as heat sinks. The temperatures are cold enough to bring CO2 down to liquid conditions at a pressure of 5.1 bar. So a CO2 vapour engine will work fine using flat panels. Earth doesn't get the right temperature ranges to make this workable, but Mars does.
interesting a temperature differential engine.... which is the makings of a Stirling engine
https://en.wikipedia.org/wiki/Stirling_engine
http://www3.nd.edu/~me463d18/Files/Dere … rmance.pdf
http://cmex.ihmc.us/data/catalog/Surfac … htTemp.jpg
http://cmex.ihmc.us/data/catalog/Surfac … tTemp.html

This is definitely my pet favourite idea for generating power on Mars. As a scientist, I know I shouldn't have them.

The 'cold source' can be stored under ground - just run polyethylene hose pipes through the regolith. The hot source is a tank of briny water that freezes as heat is withdrawn from it and is recharged at day time temperatures. Latent heat of freezing for water is about 100kWh per cubic metre. Hence, constant power supply regardless of the time of day or even time of year. Martians could actually store energy by freezing CO2 and covering it with regolith. During a period of high demand, dig it up again and subject it to day time heat. Solid CO2 heated up to 270K will release about 400MJ per m3 pressure energy as it expands to Martian pressures. And we can produce dry ice at much lower energy cost than that simply by compressing the Martian atmosphere at night time temperatures.

At the poles, if a geothermal heat source can be found with a temperature greater than about -20C, then power can be generated by heating and subliming the solid CO2 and passing the high pressure gas through a gas turbine. Or alternatively, wait until summer and store ambient solar heat as latent heat in a reservoir of liquid brine.

Terraformer · 2015-12-11 13:37:37

I wonder if carbonates could be used as an energy storage system? Decompose them using solar heat, and then pass the Martian atmosphere over them to get the energy back. In terms of heat energy, 1 kg of CaO should give off ~900 Wh when reacted with CO2, which is better than batteries at least.

Antius · 2015-12-11 15:30:38

Terraformer wrote:

I wonder if carbonates could be used as an energy storage system? Decompose them using solar heat, and then pass the Martian atmosphere over them to get the energy back. In terms of heat energy, 1 kg of CaO should give off ~900 Wh when reacted with CO2, which is better than batteries at least.

That is probably a better storage mechanism than silanes, although only about 10% of the energy density of gasoline. But the fuel is solid and would release heat without generating a shower of particulates. Maybe some sort of hybrid rocket with bypass.

Terraformer · 2015-12-11 15:47:09

I don't think it has the density required to power a rocket, to be honest. I was thinking more of some kind of boiler (using onboard liquid CO2 perhaps - sort of a combined heat engine/compressed air storage system?) that would be used to power land vehicles.

So basically, what you're suggesting doing with the brines, but using CaO to provide a smaller, portable heat source that could be easily regenerated.

EDIT: if you're doing that, you could use the exhaust CO2 to combine with the CaO to remove the need to pump outside atmosphere.

Last edited by Terraformer (2015-12-11 15:49:25)

SpaceNut · 2015-12-12 15:23:52

Antius I did not konw what the term MHD was so goggled.... https://en.wikipedia.org/wiki/Magnetohydrodynamics

Magnetohydrodynamics (MHD) (magneto fluid dynamics or hydromagnetics) is the study of the magnetic properties of electrically conducting fluids. Examples of such magneto-fluids include plasmas, liquid metals, and salt water or electrolytes. The word magnetohydrodynamics (MHD) is derived from magneto- meaning magnetic field, hydro- meaning water, and -dynamics meaning movement.

We can induce currents in a moving conductive fluid, which in turn polarizes the fluid and reciprocally changes the magnetic field itself, such as fero-fluidics a good example is in spindle motors to reduce friction.
When we think about "stored under ground - just run polyethylene hose pipes" this brings to mind geothermo heat pumps as another possible use of the stored energy.

Reading through the link I see that it relates to the megosphere that Mars is lossing as the solar winds are striping the plasma from mars and in turn its atmosphere. Will poke that topic as well.....

As Terraformer noted making use of the natural UV to decompose specific chemical combinations to create a storable energy process as well as the ability to get the energy back out.

Void · 2015-12-15 10:13:37

I am enjoying every ones work in this topic. It all seems to be good.

Scope: I am interested in trying to contribute to energy obtainment methods from Insitu materials, just after the first settlement has been provided from delivered materials.

Obviously when stimulated by other peoples work, I then try to adapt it to my thinking. This topic has been quiet for a little time, so now I will intrude and hope to add something or maybe just learn more.

So one thing needed is plastic tubing of some kind. That requires Hydrogen, most likely. While you certainly can propose electrolysis of water, this maybe is another way. However it requires the attainment of 200 to 300 degrees Centigrade, so to do it you would most likely want to bring a light weight solar concentrator from Earth at the start.
http://eandt.theiet.org/news/2013/dec/h … livine.cfm

French scientists have managed to produce hydrogen by accelerating natural processes taking place in rocks deep below the Earth’s surface, possibly opening new avenues for hydrogen production.
The team from the University Claude Bernard in Lyon, France, used aluminium oxide to speed up the process by which hydrogen is naturally produced when water interacts with olivine, a common type of rock, under high temperatures and pressures found deep underground.

I risk displaying a broad ignorance, but I am desiring that the above reaction will also provide a clay.

Other substances that might be processed in a similar way are Pyroxine, and Fieldspar.

These may be found on Mars, in Rocks, Dunes, and fine soils.

https://en.wikipedia.org/wiki/Serpentinite
Quote:

Hydrogen production by anaerobic oxidation of fayalite ferrous ions[edit]
In the absence of atmospheric oxygen (O2), in deep geological conditions prevailing far away from Earth atmosphere, hydrogen (H2) is produced by the anaerobic oxidation of ferrous ions (Fe2+) present in the crystal lattice of the iron-endmember fayalite by the protons (H+) of water.[2][3]
Considering three formula units of fayalite (Fe2(SiO4)) for the purpose of stoechiometry and reaction mass balance, four ferrous ions will undergo oxidation by water protons while the two remaining will stay unoxidised. Neglecting the orthosilicate anions not involved in the redox process, it is then possible to schematically write the two half-redox reactions as follows:
4 (Fe2+ → Fe3+ + e−) (oxidation of ferrous ions)2 (H2O + 2 e− → O2− + H2) (reduction of protons into hydrogen)
This leads to the global redox reaction involving ferrous ions oxidation by water:
4 Fe2+ + 2 H2O → 4 Fe3+ + 2 O2− + 2 H2
The two unoxidised ferrous (Fe2+) ions still available in the three formula units of fayalite finally combine with the four ferric (Fe3+) cations and oxide anions (O2−) to form two formula units of magnetite (Fe3O4).
Finally, considering the required rearrangement of the orthosilicate anions into free silica (SiO2) and free oxide anions (O2−), it is possible to write the complete reaction of anaerobic oxidation and hydrolysis of fayalite according to the following mass balance:
3 Fe2SiO4 + 2 H2O → 2 Fe3O4 + 3 SiO2 + 3 H2fayalite + water → magnetite + quartz + hydrogen
This reaction closely resembles the Schikorr reaction observed in the anaerobic oxidation of the ferrous hydroxide in contact with water:
3 Fe(OH)2 → Fe3O4 + 2 H2O + H2ferrous hydroxide → magnetite + water + hydrogen
Abiotic methane production on Mars by serpentinization[edit]
The presence of traces of methane in the atmosphere of Mars has been hypothesized to be a possible evidence for life on Mars if methane was produced by bacterial activity. Serpentinization has been proposed as an alternative non-biological source for the observed methane traces.[4][5]

So, we might have a source of Hydrogen for plastic tubing, either by electrolysis, or by in situ materials which assist the production of Hydrogen and Methane. Both cases require that some manufactured materials be imported from the Earth/Moon location to establish the initiation of the industrial process of producing Hydrogen in situ on Mars.

I presume that having Hydrogen, you may react it to Martian atmospheric gasses to get what you want. Plastics, Energy.

But you guys are trying to make a KISS power source for Mars. (Keep It Simple Stupid).
So, I will suppose that the preference is to use Hydrogen to produce plastics.

I believe that Antius has been working towards a KISS energy source, and I would like to try to contribute.

Searches by me on the internet suggest that 3D printers can manufacture the plastic tubing that is desired, if you have the plastic.

Conversation with Spacenut elsewhere suggests that clay might even be obtained from dune materials, using a centrifuge. Or if I misunderstood, the Serpentinization process will be required to produce, it, or perhaps clay can be found in places on Mars.

I will presume it can come by some method from dune materials, or loose soils.

So having clay, compressed earth blocks are really possible, I think. Bricks also, but for this purpose bricks would be overkill.

When I was much younger one of my deviant behaviors was to make a 3 sided (Tetrahedron) out of a soil with significant clay content.
I then spray painted one face, the solar face with black paint, when the object was dry enough.

I can testify, that even though I kept it in a porch which was very cold, it could hold significant heat from being exposed to sunshine, so Antius is on to something there.

From my point of view at this time it seems reasonable to construct a thermal diode composed of compressed earth blocks, and plastic tubing, and curtain walls.

You could make a 3 sided or 4 sided pyramid, or a cubic construction with compressed earth blocks, and put curtain walls, on south and north facing walls. You could have plastic fluid filled tube loops which respond to natural thermal convection.

In one part bonded to the south facing curtain wall, and in another part bonded to the north facing curtain wall.

Then heat should be stored at the top of the structure, and cold at the bottom.

You might consider carbonated water as the fluid to drive your turbine process. Heating carbonated water will likely take CO2 out of solution, cooling water will allow you to saturate it with CO2.

You might want an additional antifreeze, such as salts to be involved.

Metal plates? Sure, it just depends how you intend to unfold your expansion into higher and higher technology. But with the above (Which I mostly drew from others), is a lower tech method to get power generation in situ.

Like the ideas about chemicals Terraformer and Lewis.

Last edited by Void (2015-12-15 11:17:50)

SpaceNut · 2015-12-15 22:22:10

post on clay is now in resources

SpaceNut · 2015-12-16 23:19:30

I am reminded of the lunar parabolic reflector that has an optical cable at the focal point to bring the heat generated into a chamber.
http://fti.neep.wisc.edu/neep533/SPRING … ture41.pdf

NASA Inflatable Solar Concentrator
http://ntrs.nasa.gov/archive/nasa/casi. … 026381.pdf

http://www.psicorp.com/pdf/library/sr-1091.pdf

http://www.psicorp.com/pdf/library/SR-1395.pdf

louis · 2015-12-17 04:40:21

SpaceNut wrote:

I am reminded of the lunar parabolic reflector that has an optical cable at the focal point to bring the heat generated into a chamber.
http://fti.neep.wisc.edu/neep533/SPRING … ture41.pdf
NASA Inflatable Solar Concentrator
http://ntrs.nasa.gov/archive/nasa/casi. … 026381.pdf
http://www.psicorp.com/pdf/library/sr-1091.pdf
http://www.psicorp.com/pdf/library/SR-1395.pdf

The inflatable solar concentrator technologically looks perfect for Mars. It's amazing how little the concentrators weigh - just 20 kgs for something about 5 metres in diameter I think it was.

Although they seem to be thinking in terms of regolith processing, to support life (on the Moon, rather than Mars), I am wondering whether on Mars we could use them to operate steam turbines, and thus generate electricity.

SpaceNut · 2015-12-18 18:13:51

http://ntrs.nasa.gov/archive/nasa/casi. … 188521.pdf

http://www.lgarde.com/assets/content/fi … -1879s.pdf

http://www.eolss.net/ebooks/Sample%20Ch … -06-00.pdf

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