sci.energy

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.