Big Dumb Boosters revisited

SpaceNut · 2007-01-08 07:27:34

A concentrator makes use of relatively inexpensive materials such as plastic lenses and metal housings to capture the solar energy shining on a fairly large area and focus that energy onto a smaller area, where the solar cell is.

Concentrator Solar Cell Receiver Test Kits

One of the ways to avoid damage caused by heat is to make as part of the cell a means to remove and convert the heat energy to power.

Quantum Dots Enables New Advances in Solar Cell Industry

Battery advances where in the Zinc oxide and now in the Lithium Ion cell types but they still are very expensive and have issues.

Tom Kalbfus · 2007-01-08 08:43:11

Solar cells are also heavy, and they become less efficient as you concentrate sunlight on them, the biggest problem with Solar cells is that they don't work in cities so well, especially if you live in a high rise. If you live on the second floor of a 5 story building, all the tennants must share the same roof, and the roof won't have enough area to supply all the occupants with electricity. Also some buildings will tend to shadow others. If you wanted to supply New York City with electricity from Solar Cells, you'd have to blanket the suburbs with them, clear cutting the trees and using up expensive suburban real estate. New York City would have to be surrounded by a field of black stretching out to the horizon. Also the further north the city is, the larger the collecting array would have to be. I think it would be much better to collect power in space and then broadcast it down to Earth. Blanketing the Earth with solar cells surrounding each city is probably bad for the environment. In the North East, you'd have to clear cut forests, and this would contribute to soil erosion, also the heating effect would be similar to surrounding New York City with a giant parking lot. If you are going to waste so much valuable real estate, you might as well build the parking lot too. Raise up the solar cell collecting surface and put a parking lot underneath. New York City is in bad need of parking space anyway, so build a giant parking lot around New York City, and force them to use Mass Transit to get in. As for the people living in the Suburbs surrounding New York City, too bad for them. That house with the solar cells on the roof that is too close to New York City will have to be torn down, as well as those of all their neighbors too. Tsk tsk tsk.

C M Edwards · 2007-01-09 11:53:25

the biggest problem with Solar cells is that they don't work in cities so well, especially if you live in a high rise. If you live on the second floor of a 5 story building, all the tennants must share the same roof, and the roof won't have enough area to supply all the occupants with electricity. Also some buildings will tend to shadow others. If you wanted to supply New York City with electricity from Solar Cells, you'd have to blanket the suburbs with them...

No.

A photovoltaic cell only responds to the angle of incident light, not the angle of the cell. Thus, if the horizontal roof of the building is too small to hold an adequate array, you can put them on a well lit vertical wall instead.

The Citigroup Building,for example, a fair-sized skyscraper in New York, has an average wall area of about 1.2 hectares on each wall. About half of this is shaded during the day, and the north side is unsuitable for solar panels, so it offers about 1.8 hectares of useable wall area, or around four times its roof area (which, if you'll look at the picture, is tilted to increase its exposed area - for a flat-topped skyscraper of the same size, the wall area is seven times the roof area).

This building could be retrofitted with a 1 MW photovoltaic powerplant. Many other suitably positioned buildings in New York City could be suitable modified, including, I'll bet, about half the houses in the suburbs.

There is no reason to travel to outer space in order to find the acreage necessary for solar power conversion on Earth. Solar power satellite stations are not necessary, and are not cost effective in comparison.

Tom Kalbfus · 2007-01-09 12:44:31

the biggest problem with Solar cells is that they don't work in cities so well, especially if you live in a high rise. If you live on the second floor of a 5 story building, all the tennants must share the same roof, and the roof won't have enough area to supply all the occupants with electricity. Also some buildings will tend to shadow others. If you wanted to supply New York City with electricity from Solar Cells, you'd have to blanket the suburbs with them...
No.
A photovoltaic cell only responds to the angle of incident light, not the angle of the cell. Thus, if the horizontal roof of the building is too small to hold an adequate array, you can put them on a well lit vertical wall instead.
The Citigroup Building,for example, a fair-sized skyscraper in New York, has an average wall area of about 1.2 hectares on each wall. About half of this is shaded during the day, and the north side is unsuitable for solar panels, so it offers about 1.8 hectares of useable wall area, or around four times its roof area (which, if you'll look at the picture, is tilted to increase its exposed area - for a flat-topped skyscraper of the same size, the wall area is seven times the roof area).
This building could be retrofitted with a 1 MW photovoltaic powerplant. Many other suitably positioned buildings in New York City could be suitable modified, including, I'll bet, about half the houses in the suburbs.

New York City gets the same amount of sunlight as does an equivalent area of flat land without buildings. If you add buildings, you are increasing the available surface area, but not increasing the amount of sunlight. The more people you put in an area, the less area for solar energy there is per person. The tallest buildings stand out rising above all the others, while shadowing other buildings, but never the less the same amount of sunlight reaches the City as an equivalent area of vacant farmland. When people live close together and on top of each other, each doesn't have sifficient room to spread his solar collecting array. Most people live in cities where rooftop solar panels aren't an option. You probably need as much collecting area as the total amount of floorspace in New York city, except that solar panels can't be stacked on top of each other as people can.

There is no reason to travel to outer space in order to find the acreage necessary for solar power conversion on Earth. Solar power satellite stations are not necessary, and are not cost effective in comparison.

C M Edwards · 2007-01-10 14:42:13

If you add buildings, you are increasing the available surface area, but not increasing the amount of sunlight.

Effectively, averaged over the entire city, yes. The Citicorp building gets an increase in potential collector area at the expense of decreased illumination time for other portions of the city. However, power generation is unlikely to be completely homogenous, even with distributed solar power.

Another important consideration is that New York City uses so much electrical power that portions of the city cannot obtain enough power from outside the city - the state electrical grid won't handle it. New York City must generate about 75% of its own electricity, using power plants right in the city. If it could be generated on site by solar panels without significant cost over what it would take to upgrade the grids (upgraded in order to, say, pull in power from an SPS microwave receiver in the countryside), that would be competitive with anything that requires upgrading the power grid to pull in more electrical power from outside sources.

Estimating from US EIA and US Census records, the approximate average electrical power requirement of New York City is about 0.5 GW. That's a little over 60W per person, and can be supplied by a 10% efficient fixed solar array of 1300 hectares total area at that latitude. That's less than 2% of the land area of the city. There's no need to add new buildings just for solar power plants.

At $20/W installation costs (for any other city in the country, it'd be <$4 ), that's a total installation cost of $10 Billion (US). I'd love to be able to install a similarly sized SPS and receiver stations for that price, but I don't think we can.

The power demand of the urban area around New York City is similar, only distributed over a larger area. So, $20 billion, max.

We would do better to go solar right here on Earth, and either leave SPS alone or use it exclusively in space.

Tom Kalbfus · 2007-01-11 07:23:14

If you add buildings, you are increasing the available surface area, but not increasing the amount of sunlight.
Effectively, averaged over the entire city, yes. The Citicorp building gets an increase in potential collector area at the expense of decreased illumination time for other portions of the city. However, power generation is unlikely to be completely homogenous, even with distributed solar power.

So rich people who live in high rises above everyone else get solar power, while poor people who live in the shadows of those buildings do not. I call that hardly a colution at all.

Another important consideration is that New York City uses so much electrical power that portions of the city cannot obtain enough power from outside the city - the state electrical grid won't handle it.

Then the solution is obviously to fix the electrical grip so that it can carry more current, that does not require a work around such as adding solar panels to tall buildings. If the problem is not enough capacity, then you add more.

New York City must generate about 75% of its own electricity, using power plants right in the city. If it could be generated on site by solar panels without significant cost over what it would take to upgrade the grids (upgraded in order to, say, pull in power from an SPS microwave receiver in the countryside), that would be competitive with anything that requires upgrading the power grid to pull in more electrical power from outside sources.

The power grid needs to be upgraded anyway, we saw what happens when we do not upgrade the powergrid, and using Solar panels as an excuse not to upgrade the powerlines is a bad idea. Blanketing buildings with solar cells is an eyesore as well. How would you like to go to work in an office building whose windows are covered over with solar cells? With no natural light coming in through office windows, you'd be forced to rely on artificial illumination. and I doubt the roof of a very tall building would have enough solar collecting area to supply all the floors underneath, so, you'd end up having to cover over the sides as well, and this works for tall and skinny buildings, tall and fat building are even worse. Volume after all increases more with size than surface area.

Estimating from US EIA and US Census records, the approximate average electrical power requirement of New York City is about 0.5 GW. That's a little over 60W per person, and can be supplied by a 10% efficient fixed solar array of 1300 hectares total area at that latitude. That's less than 2% of the land area of the city. There's no need to add new buildings just for solar power plants.
At $20/W installation costs (for any other city in the country, it'd be <$4 ), that's a total installation cost of $10 Billion (US). I'd love to be able to install a similarly sized SPS and receiver stations for that price, but I don't think we can.
The power demand of the urban area around New York City is similar, only distributed over a larger area. So, $20 billion, max.
We would do better to go solar right here on Earth, and either leave SPS alone or use it exclusively in space.

Do you really want to replace the batteries of an apartment building, when they wear out? batteries are not infinitely rechargeable, they have a lifetime and need replacing.

dicktice · 2007-01-12 19:11:00

It'll take some time to review all those references. I'd hoped to stimulate a little original thought regarding one-way direct ascent to L1, but I guess that'll have to wait until after the New Year festivities, eh? In the meantime, "Happy New Year" to all of you old Mars-or-bust types, out there in cyperspace!

As promised, having survived Hogmanay with my crazy Scots friends, back to the economics of single-stage, direct ascent, one-way cargo rockets to the Moon:

So just as a thought problem to start with--assume a correctly timed straight-up launch (with the Moon's orbit directly overhead and ignoring atmosphere to simplify the problem) to reach L1 (where Moon = Earth gravity) at zero velocity (except for tangential vector due to Earth rotation) with just enough delta-vee to start accelerating towards the Moon, reverse direction and do a rocket burn, land tail-first at zero velocity, fall over under control and rest horizontally to enable dismantling and unloading of cargo by already arrived and established on-site crew of astronauts. What would be the equations of motion involved, I wonder... anyone?

dicktice · 2007-01-15 14:46:31

Well, after all that bla-bla, I finally convinced myself as to why direct ascent is NOT the way to go ... sorry to have been so dense. Some of us are plodders, eh? But, I still cling to the bare-bones of the BDB one-way trip: L-1 should not be ignored as a loiter or parking place....

Grypd · 2007-01-17 13:56:19

The most energy intensive part of modern buildings is heating and cooling. We have learned that we can use heat pumps to either lose or gain heat from any larger area like a buildings Car Park.

Other options to reduce energy demand is to use more modern LED lighting and increased use of natural lighting.

Still there is a need for power to come somewhere and that is why Nuclear is so popular at the moment. The 70s and 80s produced generations of what where then cheap to build, low emission Gas burning stations. These have been like the Oil burning power stations increasingly more expensive to run. Coal power stations are dirty. But we have learned that we can store all the emissions either in tankage or more effectively in Oil wells which use the emissions to increase pressure and so increase oil production. Hydro has improved but large electricity generators are like large solar plants dependent on enviromental and physical conditions.

So we have the possibility of using solar satelites to provide energy but the cost of the energy they produce added to initial cost will determine if its worth doing.

It comes down to simple economics and at the moment the cost to produce electricity is low enough that solar power sats dont make economic sense they cost too much to send up.

dicktice · 2007-01-17 16:51:00

I should've said, regarding L-1: zero velocity loiter or parking place for cargo rockets prior to designating landing sites at any point of the Lunar surface....

Palomar · 2007-01-19 15:11:04

I should've said, regarding L-1: zero velocity loiter or parking place for cargo rockets prior to designating landing sites at any point of the Lunar surface....

Hear, hear!

My intended comment, though, was: I still don't think it's nice to call them big dumb boosters.

dicktice · 2007-01-21 11:53:08

"Dumb," in that there'd be no crew aboard, with all astrogation, steering and decision making shared by Earth- and/or Moon-based mission control centres using remote presence, both visualy and tactily clued--just like being on-board, only with the ability perhaps to self-destruct under dire circumstances, such collision avoidance....

cjchandler · 2007-01-27 11:40:32

Dicktice, I don't think bringin the whole rocket to the lunar surface is going to save much. The only advantage would be you'd get the tanks and the engines on the lunar surface, but what's the point? The tanks will be probably alluminum or steel, but with a lunar base you'd be able to mine your own alluminum with only a little more effort than smelting the tanks. The engines would like wise be difficult to re-use. That leaves you with the payload only, so why not use more stages and maximize that? I'm not even sure that a lunar base will need metal. Moon dust is basically glass and alluminum oxide, and you can use microwaves to sinter it into building blocks, like bricks. If you need something lighter, try basalt fiber. Doesn't sound to hard to manufacture and I think you could find basalt on the moon. Instead of epoxy, maybe you could use moon dust and sinter it to keep the fibers in place.
http://www.space.com/adastra/adastra_mo … 60223.html
http://www.sfsti.uzsci.net/basalt.htm

dicktice · 2007-01-27 18:20:04

Right you are, for sometime in the future, but I venture to say you and I'll never see mining, refining, and metal fabrication operational on the Moon.

But for now, each site initially won't be so equipped. The tanks with built-in habitat partitions, etc. would provide readymade metal components, bits, and pieces, for what I would call "community junk yards" from which to throw together and/or modify ad hoc structures as needed. Works on Earth!

As for the derelict rocket engines, if the Moon is to be utilized for deep space, such as repetitious Mars freighting missions, they could be usefully employed then atteched to unshouded booster modules. The tanks too, come to think of it, eh?

And consider as well the Moon as a base for rocket misssions against potential asteroidal threats to the Earth/Moon system. Off the wall? I don't think so.

cjchandler · 2007-01-28 06:13:04

I'm going to take a leap of faith here and assume that we're talking about the upper stage of something like the seadragon. It would seem very unsafe to me to use the upper stage as a jery rigged habitat, there is only one wall, and it probably was weakened by it's flight. There would probably be little thermal insulation, and there wouldn't be any radiation shielding. So to change them around, and mess with them on the moon would take a significat amount of infrastructure, buldozers to cover them, welders to conect them. Might as well just bring a microwave and do it with the moon dust. I really don't think the engines would be useful either, if they are anything like seadragon, they are going to be way too big and you'd need to import fuel to use them.

dicktice · 2007-01-28 10:29:21

No, I've learned my lesson and realize that two stages minimum are necessary, loitering in LEO after discarding the 1st and then going on towards the Moon with the 2nd containing whatever payload, again loitering at L1, the staging point from which it would be directed anywhere on the Moon's surface--accomplished over and over until temporary outposts can be established by synchronized Apollo-type crewed missions. The 2nd stage might be splittable longwise after being toppled under thruster control, to form Quonset-type gradually covered over habitats, the regolith moving assisted by Moon buggies with blades as well as manual shoveling by the crews. Think: next generation spacesuits designed for physical work, with saunalike cleanup and waste handling facilities possible aboard the larger LEMs and then transferred to the Quonsets. The engines, having been designed to land cargo stages on the Moon, will be just right for launching skeletal booster stages from the Moon to L1 and attached to other Mars-bound hardware assemblies from other Lunar sites as well as from Earth.

cjchandler · 2007-01-28 14:15:27

Don't get me wrong, for the industrialization of space, I think a sea dragon would be wonderful, (60$ a kg to LEO!) but I don't think bringing the 2nd stage to the moon is going to be worth while. To build Quonset huts you don't need a metal cylinder, just bring an inflitable mylar tube ~ 0.5 ton and push dirt onto it. Then microwave the dirt as you drive/walk over it. It's too easy to build a shelter on the moon to warant the complexity of putting all those thrusters and guidance systems to land the second stage, and then you have the payload reduction from carrying that giant stage. Likewise I don't think the engines would be useful. Sea dragon's "small" engine had almost 60 million newtons of thrust, which means even with a 100:1 thrust to weight ratio it would weigh about 63000 kg. Even if you could import the fuel, that's way to big to be practical, unless you have some very heavy exports that need to go all in one shot.

dicktice · 2007-01-29 18:12:37

This is very interesting, in that there are real trade-offs to debate.

I've fastened upon the idea that initially anything launched from Earth that can end up on the Moon, should be allowed to do so. But in order to become purpose-made community junk piles, from which to cobble together things not capable of being planned for ahead of time, the dump-sites-of-choice should be capable of controlled, repeatable bulk cargo deliveries of water-ice, for example.

The remainder of the derelict 2nd stage comprising metal sheets, angles, rods, tubes, pulleys, cables, fittings, springs, wire, you-name-it, could be immediately reworked on site into mining props, scaffolding, hoists, solar smelters, forming jigs, fuel cracking and storage facilities ... as well as the aforementioned temporary shelter habitats.

publiusr · 2007-05-04 16:25:25

I'm still Bullish on Sea Dragon, and here is a nice way to fuel it from Sea Water.

http://forum.nasaspaceflight.com/forums … 22&start=1
http://www.energy-daily.com/reports/Flo … r_999.html

LH2 carrying LNG ships could fuel off it as well.

cIclops · 2007-05-05 04:16:03

LH2 carrying LNG ships could fuel off it as well.

LNG tankers are designed to carry natural gas at about -170 C, LH2 needs to be kept at -252 C.

GCNRevenger · 2007-05-05 06:58:18

Hydrogen has a greater tendency to go boom without much provocation too

publiusr · 2007-06-23 12:49:08

A stronger shell and good containment will be less of a bother. LH2 is light, so extra weight can go into containment.

I was thinking, with California so anti-nuke--why not put all of Americas future reactors in a handful of nuclear friendly states. Alabama could break down sea water en masse and ship it to hydrogen states.

I think Penn and Tellear advocated 200 new plants. If I had them all in Alabama, we might get laser propulsion to work after all.

We have Bowns Ferry up and running, and a new 3 billion Krupp steel plant on the way.

If only we could get our rails fixed for SRBs....

New Mars Forums

Announcement

#76 2007-01-08 07:27:34

Re: Big Dumb Boosters revisited

#77 2007-01-08 08:43:11

Re: Big Dumb Boosters revisited

#78 2007-01-09 11:53:25

Re: Big Dumb Boosters revisited

#79 2007-01-09 12:44:31

Re: Big Dumb Boosters revisited

#80 2007-01-10 14:42:13

Re: Big Dumb Boosters revisited

#81 2007-01-11 07:23:14

Re: Big Dumb Boosters revisited

#82 2007-01-12 19:11:00

Re: Big Dumb Boosters revisited

#83 2007-01-15 14:46:31

Re: Big Dumb Boosters revisited

#84 2007-01-17 13:56:19

Re: Big Dumb Boosters revisited

#85 2007-01-17 16:51:00

Re: Big Dumb Boosters revisited

#86 2007-01-19 15:11:04

Re: Big Dumb Boosters revisited

#87 2007-01-21 11:53:08

Re: Big Dumb Boosters revisited

#88 2007-01-27 11:40:32

Re: Big Dumb Boosters revisited

#89 2007-01-27 18:20:04

Re: Big Dumb Boosters revisited

#90 2007-01-28 06:13:04

Re: Big Dumb Boosters revisited

#91 2007-01-28 10:29:21

Re: Big Dumb Boosters revisited

#92 2007-01-28 14:15:27

Re: Big Dumb Boosters revisited

#93 2007-01-29 18:12:37

Re: Big Dumb Boosters revisited

#94 2007-05-04 16:25:25

Re: Big Dumb Boosters revisited

#95 2007-05-05 04:16:03

Re: Big Dumb Boosters revisited

#96 2007-05-05 06:58:18

Re: Big Dumb Boosters revisited

#97 2007-06-23 12:49:08

Re: Big Dumb Boosters revisited

Board footer