Electrical Generators
#Generally
Generators are unique parts in KSPI because, depending on the type of Generator it is set to become it can handle different types of energy which is generated by the reactor. The first type of energy is the more traditional thermal power. The second type of energy is only created by certain types of reactors and is made up of charged particles. Regardless of the type of source energy, a properly set generator can utilize it to make both the stock KSP Electric Charge and the KSPI resource called Megajoules. The third type of energy created by reactors is waste heat and is something that must be properly disposed of and is of no use to the generator (see linked article).
All sizes of generators function exactly the same, but suffer from a large penalty if they are attached to a wrong-sized reactor.
The effectiveness of an electric generator is primarily determined by its percentage of Carnot efficiency parameter. An ideal heat engine generates power at the theoretical Carnot efficiency. However, in practice most heat engines operate at a somewhat lesser efficiency. Your true efficiency is dependent on the temperature of your reactor and the temperature of your radiators. The hotter your reactor and the colder your radiators are, the closer your efficiency will be to the maximum.
Generators convert the thermal power output by a reactor into electrical power and waste heat. Their efficiency determines what percentage of that thermal power is converted into electricity. The rest becomes waste heat.
Typical heat engines in space use closed cycle Brayton gas turbines. For traditional molten salt-based fission reactors, this type of generator gives a maximum theoretical efficiency of 31%. Upgrading the electric generators changes them from Brayton Cycle Turbines to a KTEC Solid State Generator heat engine with no moving parts - this ups the theoretical efficiency to 60%!
Reactors which produce charged particles offer a slightly different scenario. Charged particles are created in great quantities by fusion reactors and to a considerably lesser extent by Uranium Nitride fueled particle bed fission reactors (the Sethlans/Akula reactors series). When using either one of these two types of reactors you can tweak the generator to a Direct Conversion mode generator instead for a superior theoretical efficiency of 85%. However, these generators only operate on charged particles which are produced in varying amounts depending on the type of reactor and/or the fuel mix being used.
For reactors that output a portion of energy as Charged Particles along with Thermal Power. You can place two generators on each side of the reactor for higher total MJ output. This is done by setting one generator to Direct Conversion Generator mode, to utilize the Charged Particles, and the other set to KTEC mode, to utilize the Thermal Power. This however precludes the use of parts that utilize Thermal Power such as Thermal Rockets or Thermal Turbojets, which must be connect directly to the reactor to function. This setup requires that the reactor produces both Charged particles and Thermal Power, and that you have unlocked the KTEC generator upgrade that comes from researching the Experimental Electronics node on the science tree.
There are several types of reactor/modes that output both Charged Particles and Thermal Power.
- Deuterium/Tritium mode with a Fusion reactor
- Deuterium/Helium-3 mode Fusion reactor
- "Sethlans"/"Akula" Fission reactors
After unlocking Experimental Electronics, Direct Conversion mode becomes the default for fusion generators. Be sure to check before launch that any generators that should be set to KTEC Solid State Generator mode have not reverted to a Direct Conversion generator mode, as it sometimes does.
This part must be connected directly to a reactor in order to function and can only utilize the output of one reactor at a time.
Below are stats for upgraded Reactor/Generator combos. Output ratings are at 55%. Results may very based on atmosphere thickness and number of radiators used.
- 62.5 cm: 0.125 t
- 1.25 m: 0.5 t
- 2.5 m: 2 t
- 3.75 m: 8 t