Nick Raaum wrote:Nice find Marcos! This system looks very promising, for starters distributed solar thermal systems of that scale will prove to be more efficient overall (once line losses and other complexities are factored in), the choice of a steam engine at that scale is also wise, in fact i'd argue that the steam engine is the only engine of choice for solar thermal since temperatures above 600 deg F become prohibitively expensive to generate and increase overall costs of solar collector. As you mention steam turbines only shine at high steady state power outputs, to which i'd also add high temps preferably of 1000 deg F +- 10 deg to the list. Part of the reason steam turbines evolved as the dominant heat engine for power generation was their ability to operate at higher temps and therefore higher efficiencies since lubrication was a non issue whereas there piston counterpart suffered above 600 deg F.
Marcos Buenijo wrote:Turns out that the steam pressures and temperatures achieved with this system, along with using irrigation water pumped by the system to cool the condenser, will allow for good efficiency. The CEO claims 30% cycle efficiency with 70% concentrator efficiency, and this would allow for 20% overall conversion of solar energy to work. This would be outstanding. However, I am skeptical about the efficiency claim. Their system does not allow for steam reheat or heat regeneration as I understand the configuration. If steam temperature is limited to 600F as the claim, and there is no reheat, then the best efficiency this system would see is the low 20's%. When the concentrator efficiency is considered, then the figure drops to about 15% net conversion of solar energy to work. Now, this is still excellent. More important, the efficiency of the system is not important - it's all about COST. In my opinion, this is where this system shines. I think it's brilliant.