The Lost Plot...
"Zen and the art of going to the lavatory"
Dedicated Power Supplies
Written By: Claire Rand
Last Updated: Saturday, 01 July 2006 10:39:01 PM
Many 'Real Life' craft have an engine that provides much of the crafts propulsion, as an afterthought almost provides power for the rest of the craft. e.g. consider a car, the engine drives the car and provides limited electrical power also.
Efficency is gained by transfering power between the engine and wheels mechanically, removing a requirement to convert to electrical energy and then back again.
Consider this in Traveller, well MegaTraveller anyway, the largest consumer of power on many craft is the through space drive (either anti-grav or thrust modules). with weapons also a consdieration on military craft. What if power could be fed into these systems with greater efficency?
To this end I use the folling 'House Rule' for craft design, a device can have a dedicated power supply, which will be smaller and more efficent than a regular power supply. How much smaller depends on the device configuration.
I assume a totally dedicated power supply (DPP Rating of 100%. This would provide for a saving of 10% to the power plants Mass, volume and more importantly fuel consumption. Its cost and thus CP requirements being unchanged.
Thus back to our car, the 'power plant', an internal combustion engine, is designed as normal, but will only take 90% of the calculated space, have 90% of the mass and use 90% of the fuel for each MW produced, with the cost and CP being unchanged.
Note the volume of the device (in this case the transmission) is unchanged, this is important to note. Only the power supply is affected by this system.
However this isn't ideal, we will almost certainly require some actual electrical power for other uses, thus we can decide that not all of the power plant is dedicated, and have a DPP of less than 100%. Note that a DPP of 0% is the same as a normal non-dedicated supply.
We may decide we would like 10% of the output to be avalible to the craft, with the remaining 90% dedicated to the drive system. This gives a DPP of 90%, but what of the savings? Well with a DPP or 90% we get 90% of the savings, thus our powerplant is 9% smaller, lighter and uses 9% less fuel (90% of the 10% savings).
This relationship is illustrated below
| D.P.P. | Saving | Vol, Mass & Fuel Usage | Comments |
|---|---|---|---|
| 100% | 10% | 90% | Totally dedicated power plant |
| 90% | 9% | 91% | |
| 80% | 8% | 92% | |
| 70% | 7% | 93% | |
| 60% | 6% | 94% | |
| 50% | 5% | 95% | |
| 40% | 4% | 96% | |
| 30% | 3% | 97% | |
| 20% | 2% | 98% | |
| 10% | 1% | 99% | |
| 0% | 0% | 100% | Normal, undedicated, power plant |
For a detailed worked example of how this actually works out have a look at the JX-425 CPP example.
