RE: Jaguar C-X75 cancelled

[CraigyMc]

Max_Torque said:

Ok, i'm going to try to say this in the simplest way i know how:
A gas turbine engine cannot ever be as efficient as a reciprocting piston engine in terms of converting fuel energy to useful work.

That must be why the country has so many large reciprocating piston engined powerplants.

Oh wait, there aren't any.

C

[Scuffers]

CraigyMc said:

That must be why the country has so many large reciprocating piston engined powerplants.

Oh wait, there aren't any.

C

That's an economic argument, not an efficiency one.

To use the same argument, show me a container ship that's turbine ?

[anonymous-user]

CraigyMc said:

Max_Torque said:

Ok, i'm going to try to say this in the simplest way i know how:
A gas turbine engine cannot ever be as efficient as a reciprocting piston engine in terms of converting fuel energy to useful work.

That must be why the country has so many large reciprocating piston engined powerplants.

Oh wait, there aren't any.

C

Ok, i'm going to try one last time ;-)

Please go and look up "surface area to volume ratio" on Wiki or something similar. When you have understood the concepts contained, then you should have a good understanding why a turbine (be that internal or external combustion, i.e. gas turbine / steam turbine) is a good solution for power generation in the MW region, but not in the kW region.

Add in the fact that heat capture, via recuporators (or condensors for their steam brethren) can easily be packaged for a static large scale power generation system (try mounting a cooling tower on your roofrack for example ;-) and the fact that for power generation, high currents are to be avoided (I2R losses) so high voltage is good, and you want 50Hz AC, so the output shaft speeds of an ultra large reciprocating piston engine (~120rpm) are too low for any practically wound generator.

Finally, until now, the fuel for large scale generation has been cheap, coal, gas, and even oil. The bigger costs are the installation and running costs, where a turbine based plant scores again. But, with the prices for all fossil fuels on the increase, this is going to change, and efficiency will be the new watch word for power generation.

However, this still has absolutely nothing to do with the fact that for low power small scale generation, a gas turbine ISN'T as efficient as a reciprocation IC engine. Which i think, is where i came in ;-)

It also is an interesting excercise to calculate (or estimate) the "round trip" power losses for a series architecture Range extender powertrain (which a turbine has to be as it cannot drive the wheels directly). Hint, every energy conversion stage has a power loss, so the primary conversion (chemical fuel to work) needs to be efficient as possible to avoid the effects of the law of ever diminising returns.