Greenhouse Architecture

Void · 2018-10-30 17:49:57

Ok, probably looking for grief, but.....

I will go direct solar here which is fairly unusual. And I will borrow from GW Johnson and Robert Dyck.

I guess I will leave open to what extent the first one(s) would be in situ.

So I am thinking of GW Johnsons Mushroom Houses, but I intend to make them very tall.

I do not have all that much faith in glass structures on their own holding a significant differential pressure long term.

However I am wondering if carbon ribbon with epoxy wrapped in rings around the glazed structure could give tensile strength where it is lacking. Perhaps several wraps at a time with an epoxy. Something like making a BFR/BFS. Still leaving enough transparency to make it worth while.

Carbon ribbon as in a space elevator even.
https://science.howstuffworks.com/space-elevator1.htm

As in GW Johnsons Mushroom House, a large counterweight to be on top.

From Robert Dyck reflectors on the ground perhaps all around it, to add illumination. Hopefully compensating for the fact that the cylinder of glass is partially opaque due to frames and the rings of carbon ribbon. Maybe to get it as productive as possible, wishing for Earth level illumination.

In this case I suggest a "White" diffused reflectance, rather than mirrored reflectance. My experience with shining a sun focus through window glass is that as the sun moves through the sky, thermal shock will break the glass. So you would want to avoid too much in the way of a "Hot Spot" shining into the glass.

And of course for such reflectors you will need a cleaning/sweeping system to get the dust off. Perhaps robotic.

If you wanted to go complex, you could have a cylindrical "Drop Curtain" that could be lowered at night, to limit heat losses. You could also deploy it during dust storms if that seemed a good thing to do.

You are probably going to have a sound metal structure to hold the glazing and the counterweight which would be on top. So that is a bummer, but living on Mars is going to require sound metal and other structures anyway.

Then you have to decide what is going to be inside of this. Will it be a vertical mechanized method as seems to be shown in the next link. https://www.nytimes.com/2016/03/27/busi … level.html

Or would you build multiple fixed floors?

Anyway if you care to do better. It's fine.

Done.

Last edited by Void (2018-10-30 18:06:29)

IanM · 2018-10-30 18:23:11

From my rather basic knowledge of radiation I think there should be a IR-reflecting sheet on the inside surface of the glass that would bounce the IR, and thus heat, back into the greenhouse and amplify the greenhouse effect. (It would also technically reflect the IR from the incoming solar radiation, but that's a small amount of the total incoming shortwave radiation.) I'm not sure how high an albedo would be necessary and at what costs of reflecting the other parts of the spectrum (particularly the shorter-wave ones, which I'd rather not have).

Void · 2018-10-30 18:57:39

That sounds good. That should buffer the daily internal temperature conditions.

I think Robert knows of a coating to exclude U.V., can't think of what it is. I am sure it is expensive. But...You get what you pay for. Have to pay if you want to play.

Done.

Last edited by Void (2018-10-30 18:59:37)

SpaceNut · 2018-10-30 19:16:29

Void, Thanks for the vertical farming hydroponic article.
image from the article:
27PROTO1-jumbo.jpg?quality=90&auto=webp

This shows artifical led lighting, custom tray designed for the plants that it will hold, adjustable tray to tray distances all in a compact but very tall rack system.

Vertical Harvest uses hydroponic farming methods inside a three-story greenhouse on a 4,500-square-foot downtown lot.
The company employs 15 people, they share 140 hours of work a week under a customized employment model.
projected 100,000 pounds of fresh produce a year.

How tall is 3 stories? google...

The floor to floor height of an office building is 3.9 meters per story, or almost 13 feet.
Residential buildings tend to have floor heights of about 3.1 meters, or 10 feet per story, and mixed-use edifices' floor heights are about 3.5 meters, or 11.5 feet per story.

work per person for the weeks harvest is less than 2 hrs a day for each person which leaves lots of time for each to do science.
Working up an appetite to eat about 18 pounds of food a day...which means we can scale down the gardens size to more closely match the crews size and it also mean less time for gardening for each member as well.

SpaceNut · 2018-10-30 20:15:54

I tried to find the mushroom shaped greenhouse but these are what I found for possible construction for mars.

RoundGreenhouse_2.jpg?1294631172

I think these are the simplest to construct if materials are brought from earth...

louis · 2018-10-31 02:26:47

I'm finding it difficult to conceptualise the "Mushroom House" - can you give us some more clues, Void? And if it's like a space elevator...why? What is the advantage?

Some thoughts:

1. There must be merit in a low pressure high CO2 internal atmosphere in order to reduce the amount of tensile strength of the greenhouse structure.

2. People have previously referred to "pop up" self-inflating greenhouses made of some type of transparent plastic - most likely to be imported from Earth. If feasible, these surely would be the best answer to surface greenhouses, especially if combined with 1. above and also if you could connect them in series.

3. Another possibility is to build greenhouses into south facing hillsides (in the northern hemisphere, that is), these would effectively be three sided structures and two of the sides would be made of rock or regolith. Only one side would be made of framed glass or plastic.

Void · 2018-10-31 07:28:42

I have about 10 minutes than an appointment.

OK, so it could be shaped a bit like Blue Origins "New Sheppard" spaceship. But would not of course be a rocket, and we would not want it to explode upward into the sky.
https://en.wikipedia.org/wiki/New_Shepard
As the joke goes perhaps in some cases shaped like a giant S** Toy.

It might be good in some cases to put a observation capsule on top of the erected greenhouse. I think people might like to spend some time reading a book in such a place, and looking outside. However you might put a big cylinder of ballast there instead. Ballast could be regolith, or water. Alternately, a plate of metal, with high tensile cables reaching end to end, from the base to the top of the device.

I did not intentionally use the construction methods of that sort of thing, but if you erected this greenhouse, you would have several issues to understand.

I believe that Josh, at one time learned me a thing. When some boosters are filled, and pressurized, this lends a stiffness to the cylindrical structure. The internal pressure helps to make the structure endure its deployment into launch forces.

As I recall, GW's Mushroom House would have had a much shorter length, and so the circumference of the device was the dominant dimension of his "Mushroom House".

I have changed it to look more like a corn silo in the Midwest of the USA.
https://en.wikipedia.org/wiki/Silo

Quote Louis:

And if it's like a space elevator...why? What is the advantage?

If you look at the original post you might see that I intend bands of carbon ribbon, around the circumference of the "Tube" of the device, the cylinder part.

And although I did not first think of it this way, the internal process might be like a certain anatomy of a certain part of one of the genders bodies. (Not wanting a banning).

That is a stiffness is achieved by pressurizing a cylinder, and having opposing structures to keep it from expanding, or exploding.
In this case, Space Elevator ribbon material made into "Hoops" around the circumference of the cylinder of the device.

I am not shy about using solutions that nature provides us.

Similarly there could be cables which run the length of the cylinder part, which would anchor at the top and bottom, to hold structure of the length of the device. This could possibly replace the need for a counterweight at the top, and might also modify the appearance of the device so that prudes are not put off.

One of the purposes of the shape of this device is so that you can put "Dumb" reflectors on a groomed contoured ground around the perimeter of the device and outward, to provide reflectance to add photons into the glass enclosure provided by the cylinder.

Gotta Go.

Done.

Last edited by Void (2018-10-31 07:50:10)

RobertDyck · 2018-10-31 08:00:04

Void wrote:

From Robert Dyck reflectors on the ground perhaps all around it, to add illumination. Hopefully compensating for the fact that the cylinder of glass is partially opaque due to frames and the rings of carbon ribbon. Maybe to get it as productive as possible, wishing for Earth level illumination.
...
If you wanted to go complex, you could have a cylindrical "Drop Curtain" that could be lowered at night, to limit heat losses. You could also deploy it during dust storms if that seemed a good thing to do.

My idea was to keep it simple. Some people want a burried greenhouse with mirrors to reflect sunlight through narrow side windows, others want to use fibre optics. Radiation on Mars surface is half that of ISS and plants are more resilient than humans. Just build a transparent greenhouse. Plastic film works for an exploration mission, but permanent settlement will require in-situ material and something that will last. Plastic film will scratch and kraze from dust storms. The easiest transparent material to make on Mars is glass. Tempered glass is harder than minerals of sand or dust so won't scratch. That's just regular that's been given a heat treatment.

Some plants thrive in shade but others require full sun. Mars get 47% as much sunlight, but Earth's atmosphere filters out some. Spectrally selective coating will block UV and control IR. A greenhouse will get 51 to 54% as much as Earth on a sunny day. For plants that thrive in shade like most vegetables, that's all they need. But grains like wheat and rice need full sun. That's why I proposed mirrors. I propose a long narrow greenhouse, at least 10 times as long as it is wide, and exactly twice as wide as it is high. Oriented perfectly east-west, with flat mirrors outside the greenhouse along both sides. At the equator at the spring and autumnal equinox the mirrors will be tilted 45° to reflect sunlight into the sides of the greenhouse. The reason for being twice as wide as high is the greenhouse will get as much sunlight from directly overhead as the mirrors so total light equals Earth. That's to satisfy plants that require full sun. At dawn light will reflect from the east into the greenhouse westward, at dusk it will reflect eastward, but still gets into the greenhouse. This means mirrors don't have to track the sun. Mirror angle will have to be adjusted for latitude and season only. That means mirrors will change 1° every 14 Mars solar days (sols). So every other week. You could automate that with a motor and worm screw, but it could also be done with a support rod with notches. An astronaut farmer in a spacesuit could adjust the support rods by hand.

The drop curtain I got from "Case for Mars" studies. The idea is to prevent cooling from radiant heat loss at night. Some have pointed out this may not be necessary if windows have a spectrally selective coating.

Last edited by RobertDyck (2018-10-31 12:19:18)

Void · 2018-10-31 11:28:09

Very helpful Robert.

I like how this is forming up, with the confirmation of your ideas.

I do intend to promote a vertical greenhouse. It does allow for hydroponic methods as mentioned previously with a carrusel.
I will mention it would allow for a spiral staircase method as well where you could have sequentially spiraled platforms. Those could be moist or wet, aquatic even, with low water flow or high water flow.
And then of course you could have fixed decks one above the other.

As for extra illumination, all the way from completely dumb reflectors, through the amount of animation of them as you have suggested, and even more animation.

We could have a robot(s) outside which could do 3 functions.
1) Adjust the ratcheting on one dimension according to seasonal progression.
2) Wind up a clock movement (Spring driven) in each Heliostat, so that it can follow the sun during the day.
3) Move the heliostat to a new location as needed.

If you wish you might pay for completely motor driven AI directed complex heliostats.

Or perhaps you would have a mix of many kinds.

So then you only buy up to the level that earns it's worth to your agricultural or industrial process.

Tasks heliostats dumb and/or smart would do might be variable. Perhaps some additional illumination of plants, perhaps heating a water tank on top of the tower. And water tanks could be distributed throughout the tower.

One very good option to hope to keep the interior of the greenhouse temperate would be either the hydroponic carrusel, or a stepped aquatic spiral stair case garden. Maybe only a trickle of water spilling from platform to platform. But obviously this would have the potential of moderating both hot and cold extremes. It would also be a way to clean water, as vapors would condensate on the walls at night and then flow as relatively pure water down those walls during the day.

……

To be honest I would like this thing to be on the equator if possible. Not certain that water is there, but that should be something that is checked along the way. I am thinking Medusae Fossae as the location to try for.
https://www.space.com/38330-water-ice-m … uator.html
Medusae Fossae, appears to be west of the four major volcano's, and at the boundary between the southern highlands and the northern lowlands, and so quite near the equator.
https://www.space.com/15859-mars-myster … igins.html

Obviously this would only be a good place to put up a greenhouse if it is confirmed that abundant water is to be had there.
But I like an equatorial location as the climate is moderate, the sunshine is as consistent seasonally as it can be on the planet I think, and there would be two winters a Martian year. A southern one toggled with a northern one.

Done.

Last edited by Void (2018-10-31 11:44:58)

Void · 2018-10-31 16:35:15

I am going to suggest an alternative to ice for any water that might be at Medusae Fossae.

I am going to suggest that perhaps an underground "Aquifer" feeds it perhaps all the way from the South Pole. Very salty.
Medusae Fossae being apparently porous, then it might be a sponge of saturated salts within an ash or dust deposit.

This then would indicate that much of the formation underground might be within a solution which would likely have oxidized the basalt, which then lowers it's chemosynthesis potential now. But not all of it should have been oxidized yet, and of course dust dunes may still fill the role is necessary.

But the good news is that minerals may have precipitated from the solution. There could be important mineral deposits buried in what apparently is a relatively soft rock.

Of course, the thing to do is find out if there is any water either of saturated salt solutions, or of ice. And then to identify valuable mineral deposits. If this all proves true, I would find it hard to turn the site down as a prime place to put a settlement.

As for vertical greenhouses, I would rather than putting an air lock on them propose to have tunnels that connect to their bottom(s).

Boring Company type tunnels. I would also propose to consider using water column isolation, so that if they deflate they don't take the whole network to a greater vacuum with them. Think sink traps like in household pluming.

The water could be suitably warm for humans to transit. Maybe they would even have under water "Cars" (Subs) to transit these water filled tunnels.

Additional benefits of such tunnels would be that you could store heat from overheated greenhouses in the water, and then release it and humidity to the greenhouses at night. The moisture would then condense in the greenhouses at night.

Additionally, chemosynthesis could be promoted in those waters, and aquaculture, fish perhaps feeding on microbial chemosynthesis plankton, and also feeding on plant scraps from the greenhouses.

The residue (Fish poo, and dead microbes) could then be collected to grow mushrooms, and the results from that to be gardening soil.

Done.

Last edited by Void (2018-10-31 16:45:45)

SpaceNut · 2018-10-31 19:03:28

There are some real nice thoughts here but until we get the landers, rovers and probe to test for what we need man will not be ready to go to be able to stay. That makes mission 1 a sortie style exploration of landed site to be able to answer the questions that we still will have for being able to stay and to be self relient.

kbd512 · 2018-10-31 20:12:31

This is parallel development stuff. As soon as we have the lander, we need the inflatable greenhouses and rovers to move the inflatables into position. It's also useful for Earth applications, which is another synergistic effect and spin-off from the space program. In addition to thin film solar arrays, I would suggest solar concentrators connected to a light pipe array so that the entire greenhouse can be protected from radiation with regolith powder bags. Part of the solar array power can split H2O into O2 and H2 so that an array of micro gas turbines can supply power to lasers that also feed their output into the light pipes for 24/7 operation. The gas turbine exhaust can be fed into duct work that feeds the sprinkler system for the greenhouse.

Void · 2018-10-31 21:50:00

Well, maybe I might speculate on a mission for BFS.

I am going to presume that if SpaceX manages to make a refueling station at say Utopia Arcadia.
https://www.geekwire.com/2017/arcadia-p … pacex-ice/

If they had time before it was appropriate to launch back to Earth, could they use a BFS as a hopper. Fuel it up, do a hop to Medusae Fossae, and still have enough fuel to hop back after they checked it out?

Not saying that I think they will, but it does bring up the question, how good of a hopper would BFS be on Mars, if you had at least one refueling station and lots of propellants? Just a curiosity.

Done.

Void · 2018-11-04 17:52:23

I will avoid a new topic.

I think I have what I want for greenhouse lakes. I think I have found harmony with the Martian environment, what it has to offer, and how to make it work for us.

I want to keep the materials for it as low cost as can be while still being effective to the purpose intended.

1) A bag of ice. Really an enclosure of transparent material, circular, and flat on the top and flat on the bottom. A deepness of the ice to be a nominal 11 feet which on Mar is roughly equivalent to a pressure load on the water below of 100 mb. The material of it to be of a more normal type of transparent "Plastic" film. Filled with liquid water, of 32 degrees, and degassed. Gasses dissolved in the water would encourage air bubbles which would interfere with transparency.

2) Above that a "Half shell", like an igloo, or like a short cylinder. With an open bottom. Nominal materials to make it with being fiberglass or mineral wool glass. It will be able to rotate on a bearing provided by the implementation of an air flow into it to lift it from the ground, and a motor system to actuate it. It will have aluminum foil inside to reflect light, or some other reflective material, if better is available.

3) Solar cells mounted to it's sunward side as counterbalance to a solar concentrating mirror on the leeward side. The solar cells will point at the sun as the device spins to follow the sun.

4) A heliostat mirror on the leeward side putting a focus to an opening on the rear of the "Half Shell".

5) In the opening a relatively small selectively transparent window of high temperature glass also able to endure thermal shocks. It will be expensive, but also small, so in that way the expense is less than a full free standing glass greenhouse.

Selectively Reflective. I will start here:
https://www.quora.com/Do-mirrors-reflec … olet-light
Quote:

Aluminum is a good reflector of UV, visible and IR light.
However, if the aluminum is on the Back Side of a piece of glass, the glass will absorb most of the UV light and therefore, No, a back-face mirror will not reflect much of the UV light. Unless the glass is special glass that has a a high transmissivity for UV.

And to that I would add that it seems reasonable to me that you could put a U.V. blocking tint to the glass, just as you can make glass of visible coloration. This of course will make the glass more expensive, but again since it is to be high temperature, and there will be less of it, then the expense may be worth it.

I am just starting to consider what type of glass. These are potential nominations, but may not be the ones.
https://en.wikipedia.org/wiki/Vycor
http://www.glassdynamicsllc.com/heatresistantglass.html

So, if the primary heliostat mirror were of aluminum, it would reflect a focus to the window of most wavelengths, but the window it is hoped would filter out much of the U.V., and I expect that the window would get hot.

So;

6) Around the window frame a pressurized metal tubing to remove heat for use. Probably liquid filled, circulating.

*Note if desperate, if not enough U.V. is filtered out, you could have a second interior pane of glass, with a coating to do the job as in EVA space helmets. But again even if this is expensive, the window would be small, so you limit costs. The second inside glaze with the protective coating would not be expected to get nearly as hot as the high temperature window on the outside.

……

It is important to point out that these windows and the "Half Shell" would not need to hold any large differential pressure. When the rotational "Half Shell" were lifted off the ground, the amount of pressure inside of it relative to Martian ambient should not be that much more, as all that is needed is to lift what should be a relatively light frame off the ground from time to time between minutes to allow it to adjust to the travel of the sun in the sky.

So, this thing would have three types of solar energy.

A) Solar panels to give electrical power without too much fuss, that power likely to provide the animation of the machine by motors and air compressors.

B) Thermal heat from the small window, extracted by fluid method, to whatever purpose. Probably to inject the heat into the lake below as in pushing steam into a heat exchanger, perhaps direct steam to water encounter.

C) The visible light spectrum to pass from the main heliostat window, through the window(s), to reflect off of the interior of the "Half Shell", and then to pass through the ice window into the waters below.

……

Then you can begin aquiculture, or even terrestrial agriculture inside of air filled transparent underwater enclosures.

The variety of options there is very large. Fresh water, salt water, cold, warm, or air filled? If air filled, completely enclosed, or a diving bell structure?

Some options but not at all, all of them:
https://phys.org/news/2018-11-scientist … algae.html

Or one of my favored ones is fairly large terrariums completely enclosed, put on a tether. That is you could plant them in a diving bell at the bottom of the water, but then could allow them to float up to the bottom of the ice window, on a cord. While you would not want to swim at that level without a pressure suit, the terrarium should be possible to be build to maintain internal pressure.

As I have mentioned before, a good combination of crops in such terrariums could be potatoes, and mushrooms. The mushrooms to break down organic materials provided to them, and the potatoes to absorb the CO2 produced by that, and to then release Oxygen to the mushrooms.

More fun could be a enclosure of warm water at the bottom of the reservoir, with a air filled habitat for humans. In some cases even greenhouses.

Actually I have said some of these things before, but now feel I have a complete setup to make it make sense.

And you could still do chemosynthesis in the water. H2 and CO2 and maybe Oxygen in the water.

Of course I will come back to things like this again.

Done.

Last edited by Void (2018-11-04 18:37:31)

Void · 2018-11-04 19:54:37

Oh, and how to construct the ice window?

Well you have the fiberglass dome which you can pressurize lightly. The "Half Shell". If you can bring the pressure inside up to 24 mb, then you should have no trouble melting a hole at the freezing point, and putting the bladder for the ice window into it, and then filling it with water, degassing the water inside, and letting it freeze.

If needed you could even put temporary extra weights on it, and perhaps seal the edges to the "Ground" temporarily. Maybe just water ice created by squirting water on the edges. A flash boiling of some of the water would leave behind ice. Or something like that. Then you could bring the pressure inside up even more. I anticipate that the pressurizing gas would simply be pressurized Martian atmosphere.

Of course you also need a way in and out, so include a door hatch with a removable air lock.

Something like that should work for installations, repairs, and replacements as required.

Done

Last edited by Void (2018-11-04 19:59:12)

Void · 2018-11-05 12:26:24

Just because I want to, I will post a bit more about the device described in the previous two posts.

I feel that both the solar panels on the front of the sun tracking device, and the heliostat(s) on the leeward side, may have weight bearing wheels, which would make sense anyway to provide a twisting force to help allow the whole device to track the sun. In the case where you want to weight down, the center "half shell" a provision to jack up each so that they are not bearing weight on the wheels should work well to weight down the half shell in the event you want to pressurize it to say 24 mb or more. As for the half shell, I anticipate it would spin slowly on a "Track", a circular channel, perhaps including a slide like Teflon. That track would be anchored to the ice below.

So in sun tracking mode it would float above the track on a cushion of air periodically, floated perhaps every few minutes during the day to re-orient to the suns location in the sky periodically. I do not know what the lifting force needed would be, but I anticipate that the shell would be rather a light frame of fiberglass with reflective foil on the interior of it.

Then during times of need to install, repair, or replace the ice window in a plastic bag, the solar panel frame and heliostat frame would be jacked up to impose additional weight on the half shell, and a sealant would be applied to the track to allow the interior to hold air in, sufficient to allow for cold water to not boil. The sealant I prefer would be ice, which would be temporary, but others can be considered.

It might make sense to have a low pressure air lock that can be temporarily attached to a hatch on the half shell, during installation, repair, or replacement of the ice window. This would of course allow people in EVA suits and the materials they need to be passed in the direction needed, between Martian ambient pressure and a somewhat elevated pressure in the interior of the half shell.

Done.

Void · 2018-11-05 12:49:23

And further in relation to posts #14, #15, and #16, I would say that a flooding method of terraforming would work much faster than simply warming the atmosphere, particularly for basins such as the northern hemisphere.

Much later basins in the southern hemisphere could be worked with such as hellas, but that would require extensive hydro constructions such as canals, and perhaps as in the Colorado aqueduct in some cases a siphon method to get water over elevated terrain.

Fresh water can at it's bottom reach 39 degf / 3.88888889 degC. With the probable leaching of salts into the water, a greater stratification is possible, perhaps the bottom waters being at 50 degF / 10 degC or more, but that is guess work.

In both cases the reservoirs would be covered with ice, as in an Antarctic dry valley lake.

The bottom being gradually thawed, and the biological activities presumed for these reservoirs suggests the potential for release of gasses to the reservoir from the thawing reservoir bottom, and also with a small effort the release of such gasses to the atmosphere, Methane, maybe CO2, and perhaps even Nitrogen, if it is locked in clathrates.

So then even with a negative estimate of the amount of gasses for terraforming, we might hope for an eventual atmospheric pressure of 3 x the current average of ~5.5 mb. Or 16.5 mb for the average, and much more for low elevations such as Hellas or the northern plains. Perhaps in some locations 24 mb, which may be enough to not require dirt coverings for the ice. Of course dust storms will determine to a large degree how ice would or would not be covered with dirt. In some cases it would be relatively transparent if dust did not accumulate.
Of course humans could also make efforts to uncover ice. But of course until an Ozone layer or a heavy contentment of Methane were present to the atmosphere, then U.V. would pass through those ice layers, without intervention. This would then suggest that for uncovered ice it might make sense to apply a U.V. absorbing pigment on top of the ice or within the ice.

As for the water cycle, it would still be likely that much water vapor would condense on the polar ice caps, so then the full deployment of the project would eventually include melting the ice caps from below, with relatively warmer water currents from the reservoirs to the polar ice cap. This should work quite well for the north ice cap. However for the south ice cap which is at high elevation, a ring "Sea" around the south ice cap would be necessary.

Done.

Void · 2018-11-06 13:40:41

And further in relation to posts #14, #15, #16, and #17, I have some afterthoughts and elaborations and alternatives.
……

First of all the high temperature outer window. An additional method to tolerate thermal shocks would be to section it like a stained glass window. Of course you could not use lead between the facets. It would have to be a higher temperature material. But by making it with multiple facets, it should be possible to further limit the harm that thermal shock could do. So the outer window would be primarily to convert infrared light and U.V. light to heat, and to block passage into the "Half Shell". And the intention as well would be to pass useful visible light into the "Half Shell" to be reflected down through the ice bag window, the ice bag window would be shaped like a large coin perhaps.

To use the heat collected I have specified channels for the passage of fluids to heat up. Most likely an Ammonia Water mix might do. It would perhaps endure the cold of night as well, so you would not have to purge it daily. We would not want to pass large quantities of Ammonia into the lakes water, and we would not want to flow a liquid with dissolved mineral content through the ducts of the outer window, so, I suggest that a containment be embedded into the waters of the lake below the ice, and that the walls of it would freely pass heat from the containment into the water. Then boiled ammonia could quench into the liquid contents of the containment and bring back a cooling fluid. In this situation it is not out of the question to consider a electrical turbine generation method. But it is not required.

There has been some question on this site about how to generate or store energy for use during dust storms, or at night. Of course as I see it the fiberglass or mineral glass dome could make a good radiator, if you provided ducting for the flow of the condensation of ammonia in that event. In this case heat would come out of the lake into containments with ammonia in them, and would boil the ammonia. Here again electrical turbines. This should work in some variation during dust storms and very well at night when it is very cold. With the inclusion of sufficient salts into the waters of the lake, stratification will allow a solar pond / Antarctic photo lake process where a saltier layer at the bottom of the lake could store at least room temperature, while a fresher layer above would be near the freezing point of water.

……

As for spinning the dome on a cushion of air, that is not required. I specified a track for the edges of the "Half Dome", including Teflon. It may be that it can be spun without an air cushion, or you could resort to wheels. In those cases, your method to pressurize the interior of the dome would be implemented only when you wanted to repair the ice bag window. In those cases then you would have a portable air compressor which would not be a permanent installation to the apparatus.

……

I guess if more comes to mind I can add it later.

Done.

Last edited by Void (2018-11-06 13:59:18)

Void · 2018-11-06 20:06:58

And further in relation to posts #14, #15, #16, #17, and #18 I have some afterthoughts and elaborations and alternatives.

I think now that I would see the "Half Shell" as having 3 porthole windows that tolerate high temperatures, and thermal shock.
I would place them 120 degrees apart around it. One in the front and two at the rear sides.

Each could be fed by heliostats that will have the ability to point to the elevation of the sun in the sky. The dome will be the pivot that further allows the sun to be tracked. The front heliostat would have a secondary mirror to deflect the light back to the dome. Solar panels can be included as needed for electrical power, on the heliostats so that they also would track the sun.

This is intended so that the heliostats and solar panels will not be blocked from the sun by the shadow of the dome "Half Shell". It also reduces the thermal shock problem by splitting one window into 3. Each may have multiple facets.

……

And although it can be that there may be a temporary airlock above the ice. It would also be possible to access the dome when it was pressurized by simply melting the contents of the ice window and emerging into the dome below, or taking the ice window bladder down lower in the water column where it might be repaired or recycled.

……

As for extracting heat from the windows, I think CO2 pressurized or even liquid might do the job as well. I believe that even if it freezes it shrinks unlike water, so cold nights might not damage the piping.

……

As for chemosynthesis promoted intentionally, it should be easy to inject Martian atmosphere into the waters, and also to generate Hydrogen to inject into the waters. I did previously mention as well that I also expect chemicals to emerge into the waters from the melting permafrost below the waters.

Done.

Last edited by Void (2018-11-06 20:08:33)

Void · 2018-11-08 13:04:57

And further in relation to posts #14, #15, #16, #17, #18, and #19 I have some afterthoughts and elaborations and alternatives.

So, perhaps a part of this offers energy of cold even during the day. It is not ready for prime time, but something to keep an eye on.
https://techxplore.com/news/2018-11-har … outer.html
Quote:

Harvesting renewable energy from the sun and outer space at the same time
by Cell Press
The apparatus that is proving the efficacy of a double-layered rooftop panel. The top layer uses the standard semiconductor materials that go into energy-harvesting solar cells, the novel materials on the bottom layer perform the cooling task. Credit: Linda Cicero, Stanford News
Scientists at Stanford University have demonstrated for the first time that heat from the sun and coldness from outer space can be collected simultaneously with a single device. Their research, published November 8 in the journal Joule, suggests that devices for harvesting solar and space energy will not compete for land space and can actually help each other function more efficiently.
Renewable energy is increasingly popular as an economical and efficient alternative to fossil fuels, with solar energy topping charts as the worldwide favorite. But there is another powerful energy source overhead that can perform just the opposite function—outer space.
"It is widely recognized that the sun is a perfect heat source nature offers human beings on Earth," says Zhen Chen, the first author of the study, who is a former postdoctoral research associate at Stanford in the group of Shanhui Fan and is currently a professor at the Southeast University of China. "It is less widely recognized that nature also offers human beings outer space as a perfect heat sink."
Objects give off heat as infrared radiation—a form of light invisible to the human eye. Most of this radiation is reflected back to Earth by particles in the atmosphere, but some of it escapes into space, allowing surfaces that emit enough radiation within the infrared range to drop below the temperature of their surroundings. Radiative cooling technology reflects copious amounts of infrared light, providing an air conditioning alternative that doesn't emit greenhouse gases. It may also help improve solar cell efficiency, which decreases the hotter solar cells become—if only the two technologies can coexist peacefully on one rooftop.
Stanford Professor Shanhui Fan (left) and postdoctoral scholar Zhen Chen examining the world's first dual-purpose solar array. The prototype technology is designed to capture energy from the sun and cool buildings at the same time. Credit: Linda Cicero, Stanford News
Chen and his colleagues developed a device combining radiative cooling with solar absorption technology. The device consists of a germanium solar absorber on top of a radiative cooler with silicon nitride, silicon, and aluminum layers enclosed in a vacuum to minimize unwanted heat loss. Both the solar absorber and the atmosphere are transparent in the mid-infrared range of 8-13 microns, offering a channel for infrared radiation from the radiative cooler to pass through to outer space. The team demonstrated that the combined device can simultaneously provide 24?C in solar heating and 29?C in radiative cooling, with the solar absorber improving the radiative cooler's performance by blocking heat from the sun.

For Mars, there should be a difference. More of a window for infrared I expect, a significant partial vacuum.

I also am not interested in collecting heat in the way they are, as I intend to have hot windows, which will be heated by blocked wavelengths of light, but will pass at least some of the visible spectrum to the interior of the dome for the ice window.

As for the dome and the heliostats and maybe the solar panels, they can serve as radiators also. In the case of the dome, and maybe the heliostats, it may be possible to use their methods with some modifications to provide significant cold even during the day.

So, I like it.

Done.

Last edited by Void (2018-11-08 13:07:19)

tahanson43206 · 2018-11-11 12:41:37

20181111 Notes for LED Lighting for NewMars Greenhouse thread

The link below points to another article about commercial applications of LED lighting for agriculture on Earth. Writer Adrian Higgins of the Washington Post picked up some insights that are new to me, and which might be of interest to NewMars readers.

https://www.dispatch.com/business/20181 … ropping-up

Begin Quotation:
In agricultural applications, LED lights are used in ways that seem to border on alchemy, changing how plants grow, when they flower, how they taste and even their levels of vitamins and antioxidants. The lights can also prolong their shelf life.
End Quotation.

The article closes with this prediction by grower Tisha Livingston:

Begin Quotation:
Five years from now, everyone is going to be living with indoor farming and wonder how we did without it.
End Quotation.

I am skeptical of this optimism for the Earth case, but consider it encouraging for Mars and other away-from-Earth locations, where exposure to surface conditions is problematic.

(th)

SpaceNut · 2018-11-11 16:24:24

Its doubtful that many will have any sort of a greenhouse let alone a small garden or planting of flowers or shrubs on earth but on Mars it will be a must to do so.

Void · 2018-12-11 13:35:08

Seems a reasonable line of thinking.

I have this, new, which is troublesome to relate into. Still, a power storage system, and the potential to extract appropriate wavelengths of light.

I see a chance to have such devices in two locations.

1) Buried in enclosures underground, with associated tunnels of human habitation. Just possibly the ability to also grow plants from the illumination potential of the very hot silicon. Some work required, much.

2) A solar power tower, somehow, a hot silicone vat at the top of a cone enclosure, looking like a sun above. This all being on the surface of mars. The power tower hot element being heated by heliostats (Which I think you hate).

Anyway chew toys for the imagination.

Ended

SpaceNut · 2019-12-12 17:47:27

Punching holes in opaque solar cells turns them transparent

opaque-solar-cell-compared-neutral-colored-transparent-solar-cell-hg.jpg

Existing transparent solar cells tend to have a reddish hue and lower efficiency, but by punching holes that are around 100 um in diameter (comparable in size to a human hair) on crystalline silicon wafers, it allows light through without coloring. The holes are then strategically spaced, so the human eye is unable to "see" the pattern. The best solar cells on the market have an efficiency of over 20 percent. The transparent neutral-colored solar cell that the research team developed demonstrated long-term stability with a high-power conversion efficiency of 12.2 percent. The next step for the team is to scale up the device to 25 cm2 (3.88 in2) and increase the efficiency to 15 percent. Furthermore, most windows are vertically placed, which causes light to hit the windows at a low angle. When hit by low angle light, the electrical current in conventional cells drops nearly 30 percent, while transparent solar cells reduce less than 4 percent--allowing it to utilize solar energy more efficiently.

http://dx.doi.org/10.1016/j.joule.2019.11.008
Research Report: "Neutral-Colored Transparent Crystalline Silicon Photovoltaics"

This makes it ideal for solar concentrated light to pass as well as to get the energy from the reflected light. This is a benefit to a natural lighted greenhouse as the panels now become part of the construction and not extra mass to supply energy.

SpaceNut · 2020-01-08 21:08:26

Lots of good information in this Farming and the geography of nutrient production for human use: a transdisciplinary analysis

The variety of crops and of livestock as well as fish biomes but not how much land or energy for each are required. Lest we forget we have hugh biomes of forest and oceans with which we would not live with as well.

So data from FOOD, LAND, POPULATION and the U.S. ECONOMY

At least 1.2 acres per person is required in order to maintain current American plus Currently the 400 gallons of oil equivalents expended to feed each American ...

Its actually more when we include the other resources which make these other food possible along with the breathable air and materials we take for granted.

Lets call it 2 acres and that converts to 8093.71 m^2 for just 1 person....or 90 meters on a side...
https://www.metric-conversions.org/area … meters.htm

So now what is the energy that we need for solar light...
Goggling mars greenhouse floor thermal insulation for heat lose calculations reference materials
Will read more tomorrow for these links

https://www.greenhousemag.com/article/t … heat-loss/

Conductive heat loss = SA x U x TD
Infiltration heat loss = 0.02 x V x C x TD

http://www.marshome.org/files2/Hublitz2.pdf
ENGINEERING CONCEPTS FOR INFLATABLE MARS SURFACE GREENHOUSES

https://farm-energy.extension.org/wp-co … tation.pdf
Greenhouse Energy Efficiency (Heating)

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