sci.energy

On 2 Mar, 22:41, "daestrom" wrote:
> "Alex" wrote in message
>
> news:ec8e7269-53ba-495e-8d1a-993d6492980e@...
>
>
>
> > 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?
>
> The proper place to apply such heat in the Brayton cycle (your gas turbine
> example) is *after* the compressor. If you did manage to duct/pipe the air
> from the turbine compressor out to some solar heater (or heat exchanger),
> you now have to figure out if the compressed air from the compressor is
> cooler or hotter than your solar equipment. Obviously if the compressor
> outlet is already hotter than your solar equipment, it's a bust.
>
> daestrom

Thanks - any idea what the target temperature would be?

Modern gas turbines employ heat exchangers to heat the compressed
reactants from the exhaust.