[rollei_list] Re: OT - Turbines generating electricity
- From: Ardeshir Mehta <ardeshir@xxxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Thu, 27 Jan 2005 22:14:58 -0500
On Thursday, January 27, 2005, at 09:28 PM, Austin Franklin wrote:
> Ardeshir,
>
>> The greatest attraction of the gas turbine, and that from which all
>> its peripheral attractions derive, is its utter simplicity and
>> directness in getting power from burning gas.
>>
>> In the internal-combustion piston engine there are pistons stopping
>> and starting, spark plugs firing, valves opening and closing,
>> camshafts camming, breaker points breaking, connecting rods rocking
>> back and forth on piston pins, perhaps even fuel injection squirting
>> intermittently. It's a wonder that all this can go on 60-70 times per
>> second in a car as one cruises on the freeway without disturbing the
>> stereo. That it does is testimony to the efficacy of year-in year-out
>> incremental development of its details.
>
> Do you understand what the characteristic operational distinctions are
> between the use of a turbine vs a piston engine? As in, why a turbine
> engine is not as good a choice as a piston engine in certain
> circumstances?
>
> Austin
Austin,
Turbine engines as made at present are very expensive to make. This is
their main drawback at present.
Besides, turbine engines are only efficient if they are powering very
heavy equipment (like a dump truck) or very fast equipment (like a
military jet) because of the high RPM's they generate. Automobiles are
neither as heavy as a dump truck, nor as fast as a military jet.
This question is also debated in experimental aircraft circles.
Turbines are better suited to aircraft (no need for very low speed,
rather constant power once airborne), but even there they are not as
efficient as a well-tuned ICE. The main reasons they are considered is
their simple construction (well, relatively), high reliability, and
superior power-to-weight ratio.
Note however that I am not promoting the turbine engine being DIRECTLY
coupled to the wheels. I am envisioning the generation of ELECTRICITY
with the turbine, which would be stored in an intermediate battery or
ultra-capacitor, and which would in turn drive the wheels electrically.
This set-up would get rid of pretty much all the operating
disadvantages of the turbine engine. It would be run at a constant
speed, and would not need to be throttled except gradually and
intermittently: just like in an aircraft. It need be only powerful
enough to replenish the battery/ultra-capacitor as the car was running,
and thus could be extremely small in comparison with an ICE of the same
power.
As for the efficiency and performance of of electrically-driven cars,
one has only to read about AC Propulsion's TZero
(<http://www.acpropulsion.com/tzero_pages/tzero_home.htm>) to be ready
to plunk down the 200 grand needed to buy one (as a Porsche owner who
was trounced by grandma driving the TZero did)!
AND I am not promoting turbines as they are made at present, which are
frightfully expensive!
Cheers.
Other related posts:
