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#101 2017-12-09 20:11:52

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 12,701

Re: Running on Compressed Air?

Which is part of the issue when using it to make methane.
So once we start to compress the CO2 for that we can use any excess gasses that are exhaust from that process to be used for this type of rover. Since this can use heat to help with the power stroke we can also keep it closed loop in that the exhaust from the engine being reprocess via a radiator to recool the exhaust gasses. A compressor attached like the AC pump on your car can bring in more CO2 while we drive around to keep pressures up.

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#102 2017-12-10 08:32:52

elderflower
Member
Registered: 2016-06-19
Posts: 879

Re: Running on Compressed Air?

CO2 can be collected using an amine adsorbent. This can then be pressurised and thermally stripped. The CO2 will then be at a higher pressure than you started with. That might need a few stages if it is at all possible at Mars pressures.  Perhaps Oldfart can advise on the possibility.
Otherwise industrial sized vacuum pumps would be employed as the low pressure stage. I know they can do this compression.

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#103 2017-12-10 15:15:58

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 12,701

Re: Running on Compressed Air?

We can also use cabin stripped co2 from the scubbers to aid in boosting the pressure we are keeping and give the means to use waste CO for the working gas as well. Since we will want more oxygen from insitu sources to replentish the cabin with.

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#104 2017-12-10 17:35:52

kbd512
Member
Registered: 2015-01-02
Posts: 1,983

Re: Running on Compressed Air?

SpaceNut,

I like it.  It fits in with the air tools for Mars design methodology.  If a re-purposed gas powered vehicle can go that far on a single tank of CO2, imagine how far a lightweight purpose built motorcycle could go.  There are no electronics to boot.  Having simple and reliable propulsion like this motorcycle can make or break a surface exploration or construction mission.  NASA should get their hands on one of these things and test the durability and longevity of the design.  It looks like a winner to me.

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#105 2017-12-17 08:43:10

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 12,701

Re: Running on Compressed Air?

To covert the stream of gasseous energy to electrical we could design a permanent magnet alternator generator as a means to to the end. This link is about how to retrofit a car alternator but the equations and how to make one are all still pertenant to making it for any application.
http://digitalcommons.calpoly.edu/cgi/v … ntext=eesp

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#106 2018-03-18 20:21:00

kbd512
Member
Registered: 2015-01-02
Posts: 1,983

Re: Running on Compressed Air?

SpaceNut,

In Queens, NY, the improper disposal of a Lithium-ion battery caused a 5 alarm fire that resulted in rail service suspensions in the surrounding area.  The takeaway from this should be that Li-ion batteries in their present form are not the technology of the future.  Solid polymer electrolytes or other forms of electrolytes and anode or cathode materials incapable of runaway "thermal events", as GM likes to call them, are badly needed.  The first time one of these uncontrolled reactions burns a grid Li-ion battery bank to the ground, then perhaps someone else will reach the same conclusion.  Although mobile applications, particularly vehicles, require extreme energy density, eventually what we end up with functions a lot like a conventional explosive in terms of the energy involved in the chemical reaction, which would be what fossil fuels are.

Perhaps some combination of battery and compressed gas power can service the mobile power requirement in a less dangerous manner.  The compressed gas could quickly accelerate a vehicle, whereupon a battery would provide sustainment power, given the substantially lower power requirement to simply stay in motion at a given velocity.

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#107 2018-03-18 21:37:11

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 12,701

Re: Running on Compressed Air?

Lithium fires not good as water helps them continue....

Make Your Own Miniature Electric Hub Motor

Hydraulic fuilds will also work to make a turning at low rpm....

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#108 2018-03-19 04:48:54

elderflower
Member
Registered: 2016-06-19
Posts: 879

Re: Running on Compressed Air?

Unscheduled discharge of large quantities of energy are going to cause trouble, regardless of the storage technology employed. Failing pressure vessels, disintegrating flywheels, shorted lead/acid batteries or capacitors or bursting dams spring to mind.

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#109 2018-03-19 20:15:04

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 12,701

Re: Running on Compressed Air?

That is where design testing is done to ensure that problems do not show over repeated uses.

high-pressure hydraulic fluid to capture and reuse energy

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#110 2018-03-20 21:49:56

kbd512
Member
Registered: 2015-01-02
Posts: 1,983

Re: Running on Compressed Air?

SpaceNut,

The work that Danielle Fong has done is very interesting, with respect to this topic.

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#111 2018-03-21 20:30:47

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 12,701

Re: Running on Compressed Air?

Lotus prototyped active hydraulics in its F1 racecars.

http://opensourceecology.org/wiki/Hybri … lic_System

I am still researching alternative methods to build and materials that are light weight is another factor

Building an Ultra Light-Weight Car, Part 1

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#112 2018-03-23 03:24:06

elderflower
Member
Registered: 2016-06-19
Posts: 879

Re: Running on Compressed Air?

Light weight cars will suffer greater deceleration when they run into massive objects (trucks, buildings and structures, boulders, heavy cars) than will current cars. Vehicle mass helps protect the occupants. Careful design may improve the situation but it can't be eliminated.
Not so much of an issue on Mars, for the early days, of course.

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