Clayton Baker

Douglas Alpenstock wrote:How about pico pumped hydro based on Earth's hydrological cycle? A passive solar heater could boil/evaporate water, pushing it upward to a condenser which feeds an elevated tank. That converts solar radiation to stored potential energy. Then, run it through a small water wheel connected to a DC motor/generator.

That's actually pretty good and just might work for the application I have in mind. I want to build one of these and use to capture large amounts of IR energy from the Sun. Allowing the steam to rise and then condensing it in an elevated tank would be a great way to store large amounts of potential energy for electrical generation when the Sun is not shining. And the whole system can operate at low pressure. I think I'm getting a concept now...

Thanks for the replies! After posting (that's how my brain works... post first, think later), I realized that the "obvious" way to do what I want to do would be to use heat exchangers after dark to create a convection draft and pass this draft through fan blades to drive a generator. I'm guessing the efficiency would be pretty low, but better than nothing. In this way, a portion of the energy from the stored heat in the water can be recovered during the night hours or whenever the Sun isn't shining. That diagram almost perfectly depicts what I had in mind in the OP.

Hi, so I'm working on a concept for a steam-driven electrical generator (steam generated by solar heat in a linear parabolic trough). That's fairly straightforward and has been done many times before, so completing the prototype for that will be "Stage 1" of my project. But I want to be able to generate plenty of electrical energy for storage or other uses so I want to generate steam even when the sun is not shining. So my concept is to heat water to near-boiling temperature at a faster rate than I can actually use it in a steam generator and then store this near-boiling water in insulated containers. This means I only have to raise the temperature a few degrees to turn that near-boiling water into steam.

So here's my question: If I use a propane burner (for example) to raise the temperature of the water to boiling and send that pressurized steam to the steam-driven generator, will this be a "net win" in terms of energy? I don't have to heat the water all the way from ambient, only just push it that last few degrees above boiling, so my thought is that I will be able to generate more total electricity than if I were to simply burn the propane in a regular, propane-fuel electrical generator. The reason I believe this is not due to some wishful-thinking violation of conservation of energy but, rather, due to the expansion of steam. Given that the water is already near boiling, the expansion effect should act like an "amplifier" on the propane burner, as though the burner is just unlocking the heat energy already stored in the water from being heated in the sunlight. Or perhaps I'm all out of whack. That's why i wanted to ask here in case anyone is aware of a system like this or knows where I can go to do more research...