New Mars Forums

Louis,  why do you believe political propaganda from sources not vetted for truth in any way?  Much of those video clips were clumsily altered (sound out of synch with picture).  They were repeated and repeated to make them look like they were more than they really were.  And they were quotes taken out of context,  from a time before the election.  It was almost 6 months later the vaccines finally became widely available under the emergency use authorization.

Why not go talk to real doctors and nurses.  They will tell you the truth about SARS-CoV-2/Covid-19 and what the vaccines do,  and how safe it is. 

You should be aware that in the US there can be an emergency use authorization before all the data has been "saucered-and-blowed",  but not until there is enough data understood to know it's gonna work.  That process is now complete with the fully-approved Pfizer vaccine,  and we expect completion in a matter of weeks for full approval of the Moderna and J&J shots.  It may be different in the UK,  but that's how we do it here in the US,  and that has been working well for us,  for a long time now.

Not to mention that these same vaccines are moving rapidly toward approval for use in children,  where the plague is circulating unchecked in schools.  Ask any teacher about that.  It'll be the same process,  emergency use authorization once most of the data are in and understood,  then full approval once all of it is in and understood.

When you ask the real medical folks,  and the real teachers,  you will get the same stories you see on the evening TV news if you watch the real broadcast networks here in the US,  not that cable crap.  Which makes the notion of some cabal controlling all the "mainstream media" exactly the false conspiracy theory that it is.

Fox news is the well-known exception that has been promoting conspiracy theories as if they were true.  Its founder Rupert Murdoch said quite plainly in public that it was entertainment for conservatives,  not a factual news service.  I heard him say it. Never believed anything from Fox ever again after I heard him say that.

GW

For Louis re #2

If you started a thread about iron air batteries, it should be possible for you to find it and to show a link to it here.

For all ... if there is someone willing to help SpaceNut to develop a collection of posts about this technology, please do so.

The company (is there more than one?) behind this development will be supported by investors.

It will have early customers and trials a multiple locations.

(th)

This is merely another vain attempt to contend with the absurd over-consumption of raw materials masquerading as "green energy"- costing the consumer a lot of greenbacks while delivering very little energy.  If the associated material consumption was not so problematic, then nobody would attempt this kind of silliness.  In point of fact, it is so problematic that we're back to throwing stuff at the wall, hoping something will stick.

1. Wood has a strength-to-weight ratio inferior to CFRP, and certainly inferior stiffness.  The material properties of wood are inconsistent, which means you need a greater safety margin to assure that the structure doesn't fail under load.  You can make a structure larger in volume to increase stiffness, but then you need more wood, further increasing demand for a building material that's already in short supply.  We can make any CFRP structure lighter than steel and concrete for a given strength / stiffness requirement.  The real fundamental engineering reason skyscrapers are made from steel and concrete, as opposed to plastic coated wood and glue, is that it takes far more energy and labor, therefore money, to fabricate composites using either CFRP or plastic coated wood.

2. Wood lacks fire and water resistance.  Fires will be far less of a problem than water intrusion, but any fire is guaranteed to destroy the structure, either outright during the fire or from water intrusion damage associated with putting out the fire.

3. Wood lacks resistance to biological agents like fungus or bacteria or termites that eat cellulose, especially over time.  If you treat the wood with something that can realistically prevent that from happening for 20 years, then it's very toxic to basic cellular processes by definition and far less recyclable into new wind turbine towers, as well as being an environmental hazard for humans to contend with.  Whereas bacteria have evolved to eat both plastics and diesel fuel in a mere 100 years, they've had hundreds of millions of years to evolve to eat cellulose.  In this instance, they've elected to coat a laminated wooden composite structure with plastic, which means it's far more energy and resource-intensive than steel.

4. Trees take decades to grow.  That process can't be "sped up" appreciably, but if it is, then the end result is wood with significantly less strength per unit weight and volume (the larger the individual growth rings, the weaker the natural composite becomes).  Maybe some form of processed bamboo or hemp fiber would work, when infused with resin, but I see using wood for millions of skyscraper-sized structures as a technological dead end, and so did all other engineers on the planet, the moment steel and concrete became available in mass quantities.  As with all other technologies, everything old is "new again", except that it's not, and some of this nonsense is getting pretty silly.

5. There is no global scalability to this solution, because it relies upon scarce natural materials fabricated using very stringent quality control, specifically because natural materials like wood are not homogeneous in nature.  Again, I'd have an easier time believing that an abundant and rapid-growth plant fiber like bamboo or hemp could serve the purpose, accepting the limitations of natural composite structures.  A single acre of hemp produces cellulose fiber tonnage equal to 4 to 5 acres of trees, except that the hemp can be harvested at least twice per year, if not three times per year in many tropical locations.  It takes 90 to 120 days to grow 10 tons of hemp fiber per acre of land, so it's utterly impossible to grow trees of any quality fast enough to keep up with hemp or fast-growing bamboo, which yields 5 to 8 tons per acre.  Pound-for-pound, hemp fiber composite is considerably stronger than high-strength steel, and 5 to 10 times stronger than wood.

I have a better question, though:

Why in the world would anyone revert back to using wood or natural fibers instead of using welding robots and jigs to turn coiled sheet steel, welded into a structure of suitable size, to make the wind turbine towers on-site, using commodity materials rather than highly specialized and expensive forged steel structures too large to transport via truck?

They make wind turbine towers out of a thick hot-forged steel tube, plate steel forged into a tube, essentially, because it's easiest to transport that to the wind turbine field.  There's no reason why we can't make larger diameter, but lighter, sheet steel honeycomb structures that are welded together on-site.  Metal aerospace structures are light yet stiff and strong by using good geometry for stiffness in conjunction with multiple thin pieces of sheet metal riveted or welded together.  Why was that solution never considered, given that these things only last for 10 to 20 years before they're replaced?  All these Modvion people have actually done is substitute much much thicker pieces of plastic coated wood for steel.

Sheet steel is also easy to cut and re-purpose or re-melt, so 10 to 20 years from now, when the turbine is defunct, a simple angle grinder or industrial tin snip can be used to deconstruct the tower, piece by piece.  If the correct thickness of sheet steel was used, then a deconstructed wind turbine towers could then become the supply source for automotive sheet metal or liquid storage tanks.  That solves the site cleanup problem, because people will recycle the material for free, in order to use it for other purposes to make money.  There's no practical way to remove a 1 to 2 inch thick tube of steel for recycling, because you need a crane and a plasma torch to do it.  Similarly, there's no practical use for a 2 inch to 6 inch thick multi-layer tube of plastic coated plywood or hemp / bamboo fiber.  Seriously, what can you turn that into?  A yearly global supply of knife handles from a singular tower?  Why is every practical solution utterly ignored in favor of outright absurdity?  SpaceX makes strong and light sheet metal structures by welding them on-site using commonly available and inexpensive coiled sheet steel, because when strength and temperature resistance matter, steel is the go-to material.

We're going to wind up living in a world with no trees left, no potable water, and no usable farmland, but hey we'll have "green energy", right?

"Just Have a Think" about that, because we're already seeing that happen.  No solution is too nutty, so long as it feeds into the religion.

For all who've posted so far .... has anyone actually watched the video Louis showed?

I haven't yet, but definitely plan to do so.

My hope was that the towers were to be built of wood, rather than the blades.

A tower made of wood can be enclosed in fire resistant material.

However, a fire in the gear box could be a risk for any tower.  Iron burns after all, but I admit ignition point is quite a bit higher than wood.

It seems to me an obvious solution is to design the gear boxes so that they stop automatically when temperature exceeds some reasonable limit.

I've never understood why the fires that occur occasionally in wind generators are allowed to happen.

Is someone trying to save a couple bucks? (or Euros?)....

Or is this just another example of sloppy engineering, to which every organization is prey?

(th)

Temperature and sink isolation are the issues for rock storage...
Barrels of water inside a greenhouse and other such tricks have been employed for centuries as a means to control an internal environment.

The geo thermal loops are usually burried in a layer of sand for heat pumps...

Even if this process was only 30% efficient overall, 30% of something is still 30% more than nothing, which is precisely what you get right now since there is no such thing as a grid scale battery and probably never will be.

Hot rocks and hot gas flowing over rocks that retain heat well has the following benefits:

1. It requires no new technology the might exist "one day", because all real engineering is based on technology that we have, not technology that we wished we had.

2. A steel tank filled hot gas like CO2 and heated rock truly is cheap and durable.  All materials used are infinitely recyclable using existing technology, unlike Lithium-ion batteries.

3. Spectacular total efficiency is far less important than spectacularly low total cost, as it relates to energy storage.  If the cost of losing 100% of the generated energy that you can't immediately put to good use is higher than the cost of storing it for later use, then this is a winner.

The salient questions are as follows:

1. How cheap and fast is it to implement (what are the hurdles to implementation)?

2. What is the dollar figure attached to losing 100% of what we're losing now?

3. Can we store that otherwise lost energy (and money) at a profit?

Louis can scoff at thermal energy storage and GW can scoff at overall efficiency, but the theoretical Carnot efficiency with a cold reservoir of -30C and a hot reservoir of 600C is 72.15%.  They're claiming 60% efficiency, so that falls within the realm of feasibility.  Is that realistically achievable or have they neglected to mention something important?  Maybe, maybe not, and yes, they probably did leave out something germane to realistically achievable overall efficiency, because they're trying to sell their invention.  That doesn't mean their invention won't work, merely that it may not achieve the efficiency touted.  It's a closed loop system, and looks like it uses re-injection of heat to increase efficiency with a multi-stage turbine, same as NREL does with their Supercritical CO2 gas turbines for solar thermal power plants.

If they're correct, then 60% of something is still a lot more energy than 0% of anything.  When I consider what we have now, I think of that as a significant improvement.

All schemes that use extreme temperatures (50% efficient SCO2 gas turbines operating at 715C), extreme materials (Lithium, Platinum, etc), or rely upon extreme efficiency (all batteries), are typically expensive, finnicky to operate, and strictly service life limited.

You know what's good about this new technology Louis has brought attention to?

It's none of those things.  It's a "middle-of-the-road" solution that could actually be practical.  I get the impression that most people don't truly understand the meaning of that word.  Practicality trumps all other considerations in the long run.  If you can run a boiler, then you can run this energy storage plant.  Humans know how to do that, because that's how our civilization is powered.

Let's just say I am extremely skeptical of the "60% efficiency" number.  This thing is a heat engine,  subject to classical thermodynamics.  The hottest point in its cycle is 600 C = 873 K.  The coldest point in its cycle is -30 C = 243 K.  The upper bound on efficiency,  never actually reached,  is the Carnot efficiency,  which for these temperatures is 0.72 (and the heat engine turbine isn't really operating between those two temperatures).  About half that might actually be feasible:  around 36%. 

1000 MW-scale power plants use heat engines (these days mostly steam or gas turbines) operating at 35-45% efficiency.  Smaller-scale,  you do worse:  an automobile engine could approach 20% in steady cruise,  but usually averages closer to 10%. 

GW

You can always bring preserved food for a science mission: canned, dehydrated, dry, etc. That's easy. But what do you do for a permanent settlement? You can't ship food from Earth, that's too expensive. For permanent settlement, you have to produce food locally. That's what this topic is about. Livestock are difficult to transport to Mars, and difficult to maintain. You need a hard wall containment of some sort, basically a pressurized barn, that livestock cannot bite/claw/kick/dig or otherwise puncture the pressure vessel. Livestock will consume oxygen and exhale CO2, requiring more oxygen recycling. Lifestock will produce manure and urine, which have to be dealt with. And livestock consume several units mass of fodder (feed) for each unit mass of meat. On a planet without a breathable atmosphere, greenhouse area per person is a concern.

Then there's the question of how you get livestock to the Red Planet. As I've posted before, imagine a cow on a spacecraft with astronauts, going through high acceleration during launch from Earth, then zero-G in Earth orbit, then moderate acceleration during TMI, then zero-G for months in transit, then high-G during Mars atmospheric entry, then a jerk as the parachute opens, and all the manoeuvres during landing. If the spacecraft uses rotation for artificial gravity like Mars Direct, then there will be a period of zero-G after TMI before the craft spins-up for artificial gravity. As it spins, the livestock will get dizzy. They'll get used to it, but it'll take a while. Upon approach to Mars, a Mars Direct style craft will cut loose the counter-weight, which will initially result in faster spin with much shorter radius. Then quickly de-spin. Then zero-G before atmospheric entry. All this will leave a cow freaking out. You would want to transport calves, as young as possible to minimize mass, but weaned from milk because Mars will not have any milk. At least not until the cows mature.

If you transport chickens, you have all the same problems, but with a smaller animal that can fly. Birds do not produce urine, their waste is mixed with their feces. I had considered transporting fertilized chicken eggs, put them in an incubator upon arrive on Mars. You can refrigerate live fertilized chicken eggs, just not as cold as a kitchen refrigerator, and no longer than 6 weeks. That isn't long enough to reach Mars. So how? Cryogenically freeze chicken embryos? That'll take serious research. Then how? A dedicated large scale livestock transport could do it, but that's seriously expensive.

That's why I've looked at vegan diet. Yes, it looks like we could transport fish, so aquaponics is possible. But elsewhere I posted the idea of mixing starch with gluten from a genetically modified yeast to produce flour. So we could produce flour without wheat. On the surface of Mars it would probably be most convenient to just grow wheat in a greenhouse. But on a large scale passenger ship, starch from chloroplast oxygen generators, and gluten from yeast grown in a vat. So this recipe for "vegan chicken" made from wheat gluten made me think. Instead of isolating "vital wheat gluten" from wheat flour, instead use the gluten produced by yeast. So the same gluten that can me mixed with starch for flour can be used on its own for "vegan chicken".