HG 2e Solar Panel p. 36 question

[phavoc]

The issue here is that Traveller has tried to stay rooted in the real world with some exceptions. Even Webers Honor verse stays within its defined tech rules.

Solar panels are real world tech and we kow how they operate. Even scling them up leaves certain physical rules in place, such as how "solar" panels work. Under MGT rules solar panels could work in the dead of space with no sun present. And that goes against the tech and common sense.

 

[fusor]

Yes, we have established that in our real world that solar panels as described in the Mongoose Traveller universe will not work. However, any Traveller Universe is not the real world, even though its background like a majority of science fiction stories starts out with links to the real world.

I was not asking if the Mongoose Traveller Science Fiction Universe solar panel rules work in the real world/universe, the quest is Does what I have written appear to be plausible in the Mongoose Traveller Science Fiction Universe?

If you want to use the wacky rules in HG 2e then go ahead and use them. Why do you need to doublecheck with anyone else? Follow the rules as stated, check the maths, done. The rules are so nonsensical anyway that it pretty much doesn't matter what numbers you use for them.

Yes, it would be nice if Traveller or any other science fiction bases game or book mirrored the real world, they do not because they are a possible outcome of the real world.

Problem is that you're taking rules from a book that were written by people who clearly either had no understanding of the subject, made basic mistakes, or simplified it so much that they totally lost the plot, and then blindly using them just because they're the rules. Which you can do if you want, I suppose, but why stick so blindly to the rules when you know full well that they don't make sense? Do you think that solar panels produce the same power regardless of star type or distance? Which would mean that all stars are actually the same, and luminosity doesn't fall off with distance? Do you realise that if that were the case then every single planet in Traveller would be in the habitable zone of a system? Because that's what that means if the physics of the Traveller universe worked that way.

The OTU obviously does use realworld physics. Yes, some aspects are fictional (grav drives and jump drives) - but that doesn't mean that everything else goes out of the window though. The rest of physics in Traveller is clearly still the same as it is here (at least where it doesn't run into other issues because of rules written by people who don't know the subject, made mistakes, or simplified it too much, which happens a lot...). Throw a ball in the air on an earthlike planet, it comes down due to gravity. Stars are different from eachother, and their luminosity does fall off with the inverse square of the distance. You can't breathe on an airless world. Newton's laws apply. All of these things are the same as here.

 

[snrdg121408]

Hello again,

To start out Traveller is a science fiction story that has been developed from the real world but it is not the real world. Yes, it has been established that Traveller Jump Drives, Maneuver Drives, and any number of other components do not work in the real world.

Solar Panels are optional rules which may or may not be used by designers. Those individuals who do not feel they are "realistic" can totally ignore them. The individuals who do not care about if they work in the real world can use them.

I am attempting to understand the Solar Panels in the MgT Universe not the real world

According to the MgT universe solar panels are described as follows:

"Extendible solar panels provide backup power for a ship’s power plant. They are typically installed in scout or mining ships, extending their range and endurance.

The tonnage consumed by enough solar panels required to power a ship is equal to 10% that of the main power plant, to a minimum of 0.5 tons. Solar panels cost MCr0.1 per ton.

If the panels are fitted to a ship without a power plant, then assume the (non–existent) power plant is sized to the ship’s basic systems and a Thrust 1 manoeuvre drive. A ship equipped with solar panels consumes power plant fuel at one–quarter the normal rate so long as it is only engaged in minimal manoeuvring and does not fire any weapons. Minimal manoeuvring does not include long periods at full thrust, so solar power alone is useless for most commercial and military vessels.

No power plant fuel is consumed, and endurance is considered infinite, if the ship is not manoeuvring or refining fuel. Jump drives cannot be engaged with solar panels deployed."

In CT/MT/TNE/T4 and MgT the fuel used by the jump drive and the power plant is liquid hydrogen. The power plant is a nuclear reactor "which is a device that initiates and controls a sustained nuclear chain reaction. Heat from nuclear fission/fusion is passed to a working fluid (water or gas), in Traveller the working fluid is liquid hydrogen, which runs, in the real world, through a steam turbine that turns an alternator generating electricity." I do not have a clue or what or how any of the Traveller universes runs the working fluid through to generate electricity.

The material quoted is from en.wikipedia.org/wiki/Nuclear_reactor and checked with http://www.euronuclear.org/1-information/energy-uses.htm, http://www.nrc.gov/reactors.html and whatisnuclear.com/articles/nucreactor.html.

If I wanted something more "realistic" I would be using TNE FF&S or better still the now out of print GURPS Traveller.

Based on the MgT Universe, not the real world, solar panels primary use is to back-up a ship's power plant. The minimum space requirement for solar panels is 0.5 d-tons or 10% of the ship's power plant. The instruction ignore the dimensions of extended solar panels. With solar panels extended the power generated allows the power plant to consume 1/4 the normal amount of L-Hyd power plant fuel.

In the MgT Universe, again not real world standards, solar panels that are used on a ship without a power plant is required to be the same d-tons as a power plant needed to generate power for the ship's basic systems and a maneuver drive capable of Thrust 1. For example a ship that requires a 3 d-ton power plant to generate the power points for ship's basic systems and a Thrust 1 maneuver could, according to MgT HG 2e p. 36 but not in the real world, would need 3 d-tons of solar panels if the power plant were removed.

Based on MgT, not the bloody real world, do I appear to have an understanding of the he instructions as written?

 

[wbnc]

however I did point out that quantum dot solar cells are only a few hundred nanometers thick, and an electroactive polymer fiber could form a semi-rigid framework...put the "dots" on a carbon nanofiber mesh and you have a film 1/10th the thickness of a sheet of paper that can self-deploy and remain deployed during routine station keeping. The framework would be a series of "wires" only a millimeter thick at max....that would allow rather large lightweight arrays in insanely small packages...that's using existing technology and concepts...insanely expensive at current TL and probably beyond current technical abilities but feasible with higher tech levels.

Then your solar panels become a solar sail, and you'd have the acceleration from that to worry about too. And it would be very fragile (I wouldn't want to imagine trying to unfurl solar panels that are that thin).

Really, I have to wonder what the point of the solar panels is here - the only possible reason I can see for having solar panels on a large spaceship is as an emergency backup (which also assumes you're going to be close enough to a bright star to get any use out of them). Otherwise, you're going to have a power plant because the power requirements for ship components is massive.

The only other use I can think of is what we have today - small drive-less probes and drones where the panels can provide all the power for the sensors. Maybe lifeboats/escape pods too.

They're certainly NOT going to be used to supplement or "extend the life of" fusion plants though, that'd just be ridiculous.

Hmm now there's an idea combine the solar sail with the solar array as a single unit...pay cost and tonnage for both systems and in the write up of the craft describe them as being one device and that to use one you have to deploy both...


I think they are intended as emergency backups, or for craft/structures that are going to be in one location for a rather extended period such as Pickets, probes or survey craft. But my key point was that is possible to develop solar panels that can be stored inboard in a very small space.

I do agree that reducing fuel consumption might be a bit much. besides here is really no reason to use both to begin with. if you are running on only basic systems, and not spending power for thrust then you simply put the reactor into "sleep" mode. at which pint you only burn a tiny amount of fuel to keep the reactors fusion reaction going.

 

[fusor]

Based on MgT, not the bloody real world, do I appear to have an understanding of the he instructions as written?

If you really insist on believing that solar panels work totally differently in MGT to how they do in the real world, then sure. You got it, well done, thumbs up.

For people who do actually care about having real world technologies mentioned in design documents such as this work as they do in the real world, what's written in HG2e for solar panels is total nonsense - hopefully some people reading this thread have appreciated my efforts in demonstrating this, at least (even if the OP does not). Whether Mongoose decide to fix it when this phase of the public playtest of the book is finished is up to them I guess.

 

[fusor]

I do agree that reducing fuel consumption might be a bit much. besides here is really no reason to use both to begin with. if you are running on only basic systems, and not spending power for thrust then you simply put the reactor into "sleep" mode. at which pint you only burn a tiny amount of fuel to keep the reactors fusion reaction going.

I don't think people really understand how much energy fusion releases. You only need to fuse about a millionth of a gram of hydrogen per second to produce 1 MW (1,000,000 joules per second) of power. Even if you only capture only 10% of that, you could harness 0.1MW of power from a single gram of hydrogen (about the same mass as your average raisin) for about 11.6 days. Does the ship have a 200MW reactor? A bit over 2 kg of hydrogen would last you two weeks at that rate. And that just assumes you're making 0.1 MW (100,000 Joules per second), which doesn't have to be the case. Now you see how daft it is for Traveller to talk about requiring huge tanks of fuel for the reactor? (heck, HG 1e claimed that a 3000 ton power plant would consume 2000 tons of fuel in two weeks?!!). At least TNE listed the fuel use in kilolitres per year, which is a lot better.

So " sleep mode" may not really be required here .

 

[snrdg121408]

Evening PDT fusor,

Based on MgT, not the bloody real world, do I appear to have an understanding of the he instructions as written?

If you really insist on believing that solar panels work totally differently in MGT to how they do in the real world, then sure. You got it, well done, thumbs up.

Thank you very much for confirming that I am following the solar panel instruction as written.

For people who do actually care about having real world technologies mentioned in design documents such as this work as they do in the real world, what's written in HG2e for solar panels is total nonsense - hopefully some people reading this thread have appreciated my efforts in demonstrating this, at least (even if the OP does not). Whether Mongoose decide to fix it when this phase of the public playtest of the book is finished is up to them I guess.

I do appreciate that you and others are attempting to make rules like MgT HG 2e solar panels instructions be more accurate. Had I not asked if I was getting the solar panels instructions down now, I have no doubt that if I posted a design using them the feedback would be what has happened here.

With your information I will not be using solar panels as written in MgT HG 2e on anything bigger that a satellite.

Thank you all for your help, even though I was unclear about what I was after. I really hope that someone at Mongoose reviews the thread, ignoring my stuff, for the information provide to make solar panels workable.

Since I have my answer that I correctly interpreted the instructions I'll avoid posting anything further about solar panels, unless it is to point someone else to the points made on how they really work.

 

[snrdg121408]

Hello again fusor,

I do agree that reducing fuel consumption might be a bit much. besides here is really no reason to use both to begin with. if you are running on only basic systems, and not spending power for thrust then you simply put the reactor into "sleep" mode. at which pint you only burn a tiny amount of fuel to keep the reactors fusion reaction going.

I don't think people really understand how much energy fusion releases. You only need to fuse about a millionth of a gram of hydrogen per second to produce 1 MW (1,000,000 joules per second) of power. Even if you only capture only 10% of that, you could harness 0.1MW of power from a single gram of hydrogen (about the same mass as your average raisin) for about 11.6 days. Does the ship have a 200MW reactor? A bit over 2 kg of hydrogen would last you two weeks at that rate. And that just assumes you're making 0.1 MW (100,000 Joules per second), which doesn't have to be the case. Now you see how daft it is for Traveller to talk about requiring huge tanks of fuel for the reactor? (heck, HG 1e claimed that a 3000 ton power plant would consume 2000 tons of fuel in two weeks?!!). At least TNE listed the fuel use in kilolitres per year, which is a lot better.

So " sleep mode" may not really be required here .

Would scramming the reactor be sending it into time out? ;-)

 

[Condottiere]

1. Even in the first edition, it was obvious that solar panelling was over efficient; I may have been the only one that actively exploited this, or may have pointed it out at various different times, which was why the wording was carried over without apparent much examination of the actual implications.

2. Having done your duty in pointing it out, and no action is taken, you can feel free to exploit it as well.

3. A compromise could be scaling efficiency precisely across the tech levels.

4. And the rules should clearly state how much juice is generated per half tonne of panelling, and maximum acceleration possible without breaking off the panelling, though it should be pointed out that they may be embedded in the hull, not deployed as sails.

5. I rather doubt the designers are ever going to go back into the quagmire of assigning actual current units of power to future gadgetry.

6. However, it's obvious they can assign actual output per half tonne of solar panelling, in scotts.

 

[AnotherDilbert]

1. Per HG 2e p. 36 "The tonnage consumed by enough solar panels required to power a ship is equal to 10% that of the main power plant, to a minimum of 0.5 tons. Solar panels cost MCr0.1 per ton. A ship equipped with solar panels consumes power plant fuel at one–quarter the normal rate so long as it is only engaged in minimal manoeuvring and does not fire any weapons."

I think that the fuel consumption rate reduction of 1/4 means that the solar panel array generates 1/4 of the power plants output. If I'm correct then a ship's power plant with an output of 60 Power Points (PP) the deployed solar panel array would generate 15 PP.

No? The fuel consumption is reduced to 1/4, so the PP is still producing 1/4 Power (or less if inefficient under partial load). Nothing is implied about the solar panels output.

3. HG 2e p. 36 "If the panels are fitted to a ship without a power plant, then assume the (non–existent) power plant is sized to the ship’s basic systems and a Thrust 1 manoeuvre drive."

A ship requires a 2 d-ton fusion power plant to generate the Power Points needed to support a ship's basic systems and a maneuver drive thrust of 1. I think the source above means that a 2 d-ton solar panel array is supposed to be the equivalent of the 2 d-ton power plant.

No? Calculate the size of the imaginary PP, then calculate the size of the solar panels, based on the imaginary PP.

Example: A TL12 1000 dT vessel would need 200 Power for basic systems and 100 Power for M-1. A 300 Power PP would be 20 dT. A solar panel for this vessel would be 20 dT × 10% = 2 dT. It would perhaps support essential basic systems, but not manoeuvring or weapons.

 

[AnotherDilbert]

Hmm now there's an idea combine the solar sail with the solar array as a single unit...pay cost and tonnage for both systems and in the write up of the craft describe them as being one device and that to use one you have to deploy both...

A 800 m × 800 m = 640 000 m2 sail/panel would generate 5 N as a sail and perhaps 640 MW as a panel. 640 MW fed into a M-drive would generate a thrust in the region of 30 000 000 N.

The solar sail effect is negligible.

An experimental sail https://en.wikipedia.org/wiki/IKAROS produced a thrust of 0,00112 N from a sail system massing about 4 kg. That would be enough to accelerate the sail (without any payload) at 0,00003 G. If you add a payload we are talking about 0,000001 G or so. Solar sails are completely obsoleted by anti-grav and M-drives.

 

[AnotherDilbert]

Let's assume a stellar tech solar panel that is a thin film with say 70% efficiency. That is theoretically quite possible, if I understand it correctly. Let's further say that the deployed film masses like the existing Ikaros sail, about 0,01 kg / m2. At 70% efficiency 1 m2 would generate 1 kW.

To power essential basic systems of a 100 dT vessel we need 10 Power or very roughly 100 MW. To get 100 MW we would need a solar panel of about 100 000 m2, it would mass 1 000 kg and have a volume of about 100 000 m2 × 7,5 µm = 0,75 m3 or 0,055 dT.

A Traveller solar panel for that vessel would be 0,5 dT.

Even if it is perhaps a bit optimistic to pack that deployable 0,055 dT film into 0,5 dT without damaging anything, it would be theoretically possible to produce a solar film with the requisite power and volume.

We cannot dismiss the MgT2 solar panels out of hand.

 

[snrdg121408]

Morning PDT AnotherDilbert,

Many thank for your for the reply.

1. Per HG 2e p. 36 "The tonnage consumed by enough solar panels required to power a ship is equal to 10% that of the main power plant, to a minimum of 0.5 tons. Solar panels cost MCr0.1 per ton. A ship equipped with solar panels consumes power plant fuel at one–quarter the normal rate so long as it is only engaged in minimal manoeuvring and does not fire any weapons."

I think that the fuel consumption rate reduction of 1/4 means that the solar panel array generates 1/4 of the power plants output. If I'm correct then a ship's power plant with an output of 60 Power Points (PP) the deployed solar panel array would generate 15 PP.

No? The fuel consumption is reduced to 1/4, so the PP is still producing 1/4 Power (or less if inefficient under partial load). Nothing is implied about the solar panels output.

I dropped the above comment in my post with the time stamp Sun Sep 04, 2016 4:39 am. Good to know that I was putting my own spin on the instructions.

3. HG 2e p. 36 "If the panels are fitted to a ship without a power plant, then assume the (non–existent) power plant is sized to the ship’s basic systems and a Thrust 1 manoeuvre drive."

A ship requires a 2 d-ton fusion power plant to generate the Power Points needed to support a ship's basic systems and a maneuver drive thrust of 1. I think the source above means that a 2 d-ton solar panel array is supposed to be the equivalent of the 2 d-ton power plant.

No? Calculate the size of the imaginary PP, then calculate the size of the solar panels, based on the imaginary PP.

Example: A TL12 1000 dT vessel would need 200 Power for basic systems and 100 Power for M-1. A 300 Power PP would be 20 dT. A solar panel for this vessel would be 20 dT × 10% = 2 dT. It would perhaps support essential basic systems, but not manoeuvring or weapons.

In my original post I think I followed your example then in the last couple of posts I switched gears and headed off in the wrong direction. Thank you for confirming that I was on the right page, perhaps not the right sentence, in my first.

On a different note I think I figured out why some of my posts have not shown up. While I was working on my replies yesterday PDT notifications piled up. When I clicked on submit instead of being posted the replies went to Preview which I thought was the forum page and I moved on to the notification list.

 

[fusor]

Even if it is perhaps a bit optimistic to pack that deployable 0,055 dT film into 0,5 dT without damaging anything, it would be theoretically possible to produce a solar film with the requisite power and volume.

We cannot dismiss the MgT2 solar panels out of hand.

The ISS has 27,000m² of solar panels, and that generates about 120 kW of power at earth's distance from the sun (https://www.nasa.gov/mission_pages/station/structure/elements/solar_arrays.html).

100,000m² is going to be a bit unwieldy for pretty much anything (and 70% efficiency is being pretty optimistic too).

 

[-Daniel-]

.... and 70% efficiency is being pretty optimistic too.

Is there no point where we allow optimistic for the sake of the game? Is it so very bad to say "Let's allow the dream that 70% has been reached" just for the fun of it?

Sometimes I get the desire to make the science of the game closer to that of the real world. But then there is a point where I feel like we need to remember this is a game and it's focus is for the adventure. If it were meant to be a scientific simulation then I could see pushing the science harder to be even more accurate. But it isn't. It is a Role Playing Game. :mrgreen:

 

[AnotherDilbert]

The reason I assumed 70% is very prosaic: It makes my calculations simpler, it means that 1 m2 gives 1 kW (in Earth orbit).

I checked Quantum Dots as wbnc suggested, it seems to be projected that theoretical maximum would be 86%, so 70% is not out of the question.

So 70% isn't all that optimistic, but 70% after a few years in space might be*, and the material strength to keep a 100 000 m2 sheet of 7,5 µm thickness together and pointed at the Sun, might be a bit optimistic.


* Solar panels degrade rather quickly in space, but I have no idea if that applies to Quantum Dots.

 

[Condottiere]

As written, it has the potential to be a perpetual motion machine.

 

[-Daniel-]

As written, it has the potential to be a perpetual motion machine.

:lol: Would be quite interesting if it could be. Endless energy at no cost.

 

[wbnc]

As written, it has the potential to be a perpetual motion machine.

:lol: Would be quite interesting if it could be. Endless energy at no cost.

Its not a closed system it's constantly receiving energy from an outside source..that massive ten gazillion ton fusion reactor nearby. The device just converts photons into electrons.

 

[-Daniel-]

As written, it has the potential to be a perpetual motion machine.

:lol: Would be quite interesting if it could be. Endless energy at no cost.

Its not a closed system it's constantly receiving energy from an outside source..that massive ten gazillion ton fusion reactor nearby. The device just converts photons into electrons.

Oh I understand that. I was just saying that if he could figure out how to make a perpetual motion machine it would be interesting.