sci.energy

Alex wrote:

> On 1 Mar, 23:45, Eeyore
> wrote:
> > Alex wrote:
> > > Just a thought ...
> >
> > > Has anyone tried using solar thermal power as a pre-heater for thermal
> > > power stations (gas or coal?)
> >
> > > Imagine a 20 Hectare solar collector field supplying about 200MW of
> > > heat. This is used to preheat air and natural gas, prior to combustion
> > > in gas turbines.
> >
> > > Input: 200MW solar and 800MW gas
> > > Output: 500MW electric
> >
> > > Advantages:
> >
> > > - The heat is converted to electricity at an effective efficiency of
> > > that of the plant, about 50% for gas turbines.
> > > - The circulatory fluid is only heated to about 200-300C - quite
> > > manageable with limited losses
> > > - The heat can be stored in a molten salt and released when there's no
> > > sun
> >
> > > Any problems with this?
> >
> > Yes, the heat is low temperature and no use for the application.
> >
> > Power stations actually need to GET RID of 'low grade' heat !
> >
> Yes, they need to get rid of 50 degrees C or so out the back end. If
> you've got a good coastal site it could even be worth pumping cold
> water up for 50m below.
>
> But preheating your input gases to 200-300 degrees means you can
> increase the air:fuel ratio and still get the same temperature in the
> combustion chamber.

How do you propose to get significant amounts of 200-300 degree heat ?

Graham