[rollei_list] Re: OT - Turbines generating electricity
- From: Jerry Lehrer <jerryleh@xxxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Thu, 27 Jan 2005 13:31:34 -0800
Richard,
The fuel does NOT have to be volatile. A Caterpillar diesel, with
it's large diameter jets, can be set up to run on Vaseline!
Jerry
Richard Knoppow wrote:
> ----- Original Message -----
> From: "David Seifert" <dseifert@xxxxxxxxxxxx>
> To: <rollei_list@xxxxxxxxxxxxx>
> Sent: Thursday, January 27, 2005 10:11 AM
> Subject: [rollei_list] Re: OT - Turbines generating
> electricity
>
> > Ardeshir,
> >
> > I certainly wouldn't characterize this as a "trend" in
> > shipbuilding.
> > The vast majority of tonnage is being built with really
> > conventional low
> > or medium speed diesel engines driving shafts via gearing.
> > While gas
> > turbines are, indeed, quite efficient in the weight/power
> > ratio, weight
> > is seldom much of an issue for a large vessel. There are
> > a couple of
> > issues, first is the cost of fuel. Jet A costs a lot more
> > than bunker
> > fuel and the prices are much more volatile too! Second is
> > a highly
> > inefficient conversion of heat to electricity. None of
> > the heat in the
> > exhaust gasses are converted to electricity and are thus
> > wasted unless
> > you go to a very fancy system like GE created for Chantier
> > and
> > Celebrity. In this system the hot exhaust gasses are used
> > to heat water
> > which, in turn, runs a steam turbine which generates yet
> > more
> > electricity. This goes a long way to solve the heat
> > recapture problem
> > without messing with the efficiency of the gas turbine.
> > Again, a very
> > elaborate (and fairly large) system to improve on the
> > fundamentally weak
> > fuel efficiency problem of gas turbines.
> >
> > I have sailed on both diesel (both geared and
> > diesel-electric) and
> > turbine (both steam and gas) powered commercial vessels
> > and I can tell
> > you there is a distinct difference. The turbine powered
> > ships are much
> > smoother and vibration free. Other than the cachet
> > Celebrity was
> > convinced to go gas turbine not for the fuel efficiency
> > reasons (there
> > are none) but for space efficiency. The power plant is
> > much smaller
> > than an equivalent diesel system and thus provides more
> > revenue space.
> > Completely different economics.
> >
> > Needless to say, none of this applies to cars!
> >
> > Best,
> > David
> >
> > Ardeshir Mehta wrote:
> >
> I was not aware that marine deisels burned bunker oil, I
> thought that was confined to boilers. It must need to be
> heated to get it volitile enough.
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx
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