More "realistic" Power Plants (CT: Striker & MegaTraveller)

[atpollard]

I posted some art in "Civilian Wheeled Vehicles [IMTU]" recently. Those IMTU vehicles employ Fuel Cells that deviate from the RAW values found in Book 8: Robots and MT. I have created this topic to share my HOUSE RULES. These spring from two primary sources:

1. Aramis posted a calculation [by Chris Thrash] in one of many discussions on "FUEL CONSUMPTION" not working [engines are often greater than 100% efficient at converting chemical energy into electricity and sometimes 1000% efficient]

2. REAL WORLD data on these engines. There were Fuel Cells on the Gemini Spacecraft, so they are NOT TL 10+ per MT. Their efficiency can be researched, as well as their size and weight from the 1960's through 2024. That provides the start of a trend from TL 6-8.

I made an arbitrary decision to set 100% efficiency at TL 17 (matter to energy conversion) and scale the efficiency from the known values to 100% as TLs progressed. I drew from STRIKER, Book 8, MT, and TNE:FF&S (in that order of preference) for data in an effort to create Classic Traveller Vehicles in the TL 8 to TL 12 range. Vehicles below TL 8 could be drawn from real examples and just converted to Traveller Stats, so there was less need, and vehicles above TL 12 were already plentiful in the game. I saw a general shortage of TL 8-10 Civilian Vehicles.

FUEL CELLS

MAXIMUM EFFICIENCY:
Hydrogen combustion = 286 kJ/mol = 78.8 wH/g
Hydrogen, liquid = 0.070 kg/L = 70g/L
78.8wH/g x 70g/L = 5517.9 wH/L = 5.518 KwH/L = 0.181 L/kW-h [100% efficiency]

REAL WORLD Fuel Cells have a theoretical maximum chemical efficiency (100%) of 5.5179 kW-h per Liter of LH2. Setting this [0.181 L/kW-h] as the efficiency at TL 17 and subtracting 2% efficiency per TL to reach 80% efficiency at TL 7 [approximate Real World Values], yields more realistic Fuel Cells. The basic unit is the 1 kW Fuel Cell, which can be clustered together to create a Power Plant of any desired output.

THE FUEL (LH2):
Liquid Hydrogen Fuel: 1 Liter = 0.07 kg, Cr 0.035

THE TL 6-9 FUEL CELL:
(TL 6) Fuel Cell = 1 kW, 1.3 liter, 2.7 kg, Cr 20
1 kW-h LH2 Fuel Tank = 0.23 liter; 0.016 kg; Cr 0.008

THE TL 10-12 FUEL CELL:
(TL 10) Fuel Cell = 1 kW, 1.0 liter, 2 kg, Cr 20
1 kW-h LH2 Fuel Tank = 0.21 liter; 0.015 kg; Cr 0.007

THE TL 13-14 FUEL CELL:
(TL 13) Fuel Cell = 1 kW, 0.7 liter, 1.4 kg, Cr 20
1 kW-h LH2 Fuel Tank = 0.20 liter; 0.014 kg; Cr 0.007

THE TL 15 FUEL CELL:
(TL 15) Fuel Cell = 1 kW, 0.3 liter, 0.7 kg, Cr 20
1 kW-h LH2 Fuel Tank = 0.19 liter; 0.013 kg; Cr 0.007

THE TL 16 FUEL CELL:
(TL 16) Fuel Cell = 1 kW, 0.3 liter, 0.6 kg, Cr 20
1 kW-h LH2 Fuel Tank = 0.18 liter; 0.013 kg; Cr 0.006

[EDIT: add "by Chris Thrash"]

 

[atpollard]

Internal Combustion:​

Gasoline combustion = 5470 kJ/mol = 12.5 wH/g
Gasoline, liquid = 0.755 kg/L = 755g/L
12.5wH/g x 755g/L = 9437.5 wH/L = 9.437 KwH/L = 0.106 L/kW-h [100% efficiency]

REAL WORLD Hydrocarbon Fuels (irrespective of engine technology) have a theoretical maximum chemical efficiency (100%) of 9.437 kW-h per Liter of Hydrocarbon Fuel (Gasoline) [0.106 L/kW-h]. Setting the efficiency at 30% at TL 5, 40% at TL6, 50% at TL7 and 60% at TL8, yields fuel consumption rates that are slightly optimistic, but much closer to realistic and transition well to the more realistic Hydrogen Fuel Cell technology at TL 9 and higher.

THE FUEL (HYDROCARBON):
Hydrocarbon Fuel: 1 Liter = 0.8 kg, Cr 0.25

THE TL 5 INTERNAL COMBUSTION ENGINE:
(TL 5) Internal Combustion Engine = 1 kW, 4 liter, 4 kg, Cr 4

• MT: If kW<25, then 3x (liter, kg, Cr)

1 kW-h Hydrocarbon Fuel Tank = 0.35 liter; 0.28 kg; Cr 0.09


THE TL 6 IMPROVED INTERNAL COMBUSTION ENGINE:
(TL 6) Improved Internal Combustion Engine = 1 kW, 2.5 liter, 2.5 kg, Cr 5

• MT: If kW<40, then 3x (liter, kg, Cr)

1 kW-h Hydrocarbon Fuel Tank = 0.27 liter; 0.22 kg; Cr 0.07


THE TL 7 GAS TURBINE ENGINE:
(TL 7) Gas Turbine Engine = 1 kW, 1.7 liter, 1.7 kg, Cr 8

• MT: If kW<60, then 3x (liter, kg, Cr)

1 kW-h Hydrocarbon Fuel Tank = 0.21 liter; 0.17 kg; Cr 0.06


THE TL 8 MHD GENERATOR:
(TL 8) MHD Generator = 1 kW, 1.25 liter; 1.25 kg; Cr 12.5

• MT: If kW<80, then 3x (liter, kg, Cr)

1 kW-h Hydrocarbon Fuel Tank = 0.18 liter; 0.14 kg; Cr 0.05

 

[atpollard]

I originally started working on this to create ROBOTS, so here is the data on BATTERIES:

CHEMICAL BATTERIES:​

The following BATTERIES are from STRIKER and MEGATRAVELLER converted to a “per Kilowatt-hour” format rather than per cubic meter. For all BATTERIES, 1 kilogram = 1 liter.

TL 5 Battery: [Lead Acid]
1 kW-h = 10 kg; Cr 50

TL 6 Battery: [Alkaline]
1 kW-h = 5.0 kg; Cr 20

TL 7 Battery: [Nickel Metal Halide]
1 kW-h = 3.3 kg; Cr 10

TL 8 Battery: [Lithium Ion]
1 kW-h = 2.5 kg; Cr 8.1

TL 9 Battery: [Zinc-Oxygen
1 kW-h = 1.7 kg; Cr 6.4

TL 10 Battery: [Iron-Oxygen]
1 kW-h = 1.3 kg; Cr 6.7

TL 11 Battery: [Sodium-Oxygen]
1 kW-h = 1.1 kg; Cr 7.4

TL 12 Battery: [Lithium-Sulfur]
1 kW-h = 1.0 kg; Cr 8.5

TL 13 Battery: [Magnesium-Oxygen]
1 kW-h = 0.33 kg; Cr 10

TL 14 Battery: [Aluminum-Oxygen]
1 kW-h = 0.25 kg; Cr 13

TL 15 Battery: [Lithium-Oxygen]
1 kW-h = 0.14 kg; Cr 14

 

[atpollard]

ATOMIC BATTERIES:​

STARTING DATA:
NASA MMRTG Power Module = 2.0 kW (t) / 0.11 kW (e); 4 kg Pu238; 45 kg total
NASA GPHS-RTG Power Module = 4.4 kW (t) / 0.3 kW (e); 7.8 kg Pu238; 56 kg total
Pu235 = $40 million per 45 kg = MCr 0.178 per kg [use MCr 0.180/kg]
Pu235 = 2 kg = 1 kw thermal = 1 kw electric @ 100% efficiency = MCr 0.360
FF&S Fission PP (TL 6) = 1 kW (e); 33 kg; Cr 333 [negligible cost compared to Pu235]

An ATOMIC BATTERY (aka. nuclear battery, radioisotope battery or radioisotope generator) uses energy from the decay of a radioactive isotope to generate electricity through non-electrochemical processes. They cannot be charged/recharged and are expensive, but they have extremely long operating lives and high energy density. Used as power sources for equipment that must operate unattended for long periods in inaccessible locations (spacecraft, pacemakers, underwater systems, and automated stations). Atomic Batteries are rated in Kilowatts (kW) rather than kW-h because they generate slowly decreasing power, reaching half their rated power in about 100 years and making the kW virtually fixed and the hours virtually infinite. [Note: The percentages are the efficiency at converting thermal output from the decay of Pu238 into electricity. All technologies are cumulative to capture more of the energy. Weights are based on NASA data for RTG generators and Prices are based on the cost to manufacture Pu238 adjusted for theoretical increases in efficiency with TL.]

TL 6 Thermo-Electric Generator: (5% efficient)
1 kW = 320 kg; MCr 7.200

TL 7 Thermo-Photovoltaic Generator: (20% efficient)
1 kW = 80 kg; MCr 1.800

TL 8 Stirling Generator: (40% efficient)
1 kW = 40 kg; MCr 0.900

TL 9 Electrostatic Generator: (60% efficient)
1 kW = 27 kg; MCr 0.600

TL 10 Radio-Voltaic Generator: (80% efficient)
1 kW = 20 kg; MCr 0.450

 

[whartung]

THE TL 6-9 FUEL CELL:
(TL 6) Fuel Cell = 1 kW, 1.3 liter, 2.7 kg, Cr 20
1 kW-h LH2 Fuel Tank = 0.23 liter; 0.016 kg; Cr 0.008

So, for the fuel tank. Is there enough insulation etc. for that small fuel tank to keep the LH2 as LH2? Is the vessel under particularly high pressure?

THE TL 5 INTERNAL COMBUSTION ENGINE:
(TL 5) Internal Combustion Engine = 1 kW, 4 liter, 4 kg, Cr 4

• MT: If kW<25, then 3x (liter, kg, Cr)

1 kW-h Hydrocarbon Fuel Tank = 0.35 liter; 0.28 kg; Cr 0.09

What does "MT" mean here?

 

[kilemall]

So, for the fuel tank. Is there enough insulation etc. for that small fuel tank to keep the LH2 as LH2? Is the vessel under particularly high pressure?


What does "MT" mean here?

Mega traveller I assume. It’s kind of in that same CT/LBB8/Striker family of powergen assumptions.

The thing I found myself changing was the air breather jet engines. Just not the jump in power that should be there.

 

[atpollard]

So, for the fuel tank. Is there enough insulation etc. for that small fuel tank to keep the LH2 as LH2? Is the vessel under particularly high pressure?

Classic Traveller (CT), Striker, Book 8 Robots, MegaTraveller and TNE:Fire, Fusion & Steel all ignored the issue of insulation around LH2 fuel tanks in any and all Power Plant calculation, so I saw no need to add that level of complexity to CT vehicle or robot design. The required insulation would follow a 2/3 power progression ... decreasing as the tank got larger (as a percentage of weight or volume). That was enough of a P.I.T.A. for the shell of a vehicle.

Indirectly, it is accounted for in the "volume" calculations on the spreadsheet I use to create vehicles in the generic "shell" that encloses all components and follows the ^2/3 curve ... then gets promptly ignored in the final result because nobody cares how many liters a Pickup truck really is [which is wildly inaccurate anyway since the cargo bed is open and the cargo varies in density.]

What does "MT" mean here?

MegaTraveller. It is a note that in MT design there is a penalty for small engines not found in other rules like Striker (and often not found in real life).

 

[atpollard]

The thing I found myself changing was the air breather jet engines. Just not the jump in power that should be there.

Do you have a link to your changes?
I am always interested in better data to check against the RAW.

I did not get into POWER, but I did note that Jet engines are available VERY SMALL on Amazon ... so the "minimum size" needed to be looked at.

 

[kilemall]

Do you have a link to your changes?
I am always interested in better data to check against the RAW.

I did not get into POWER, but I did note that Jet engines are available VERY SMALL on Amazon ... so the "minimum size" needed to be looked at.

Just power output for 1950s 70s 90s etc. definitely more than the progression in the design sequence. Not a specific single resource, just looking up thrust to engine weight for representation per decade.

 

[aramis]

I posted some art in "Civilian Wheeled Vehicles [IMTU]" recently. Those IMTU vehicles employ Fuel Cells that deviate from the RAW values found in Book 8: Robots and MT. I have created this topic to share my HOUSE RULES. These spring from two primary sources:

1. Aramis posted a calculation in one of many discussions on "FUEL CONSUMPTION" not working [engines are often greater than 100% efficient at converting chemical energy into electricity and sometimes 1000% efficient]

I was redoing math by Chris Thrash on the TML. Put the credit where it was due.