I assume you're in India; If so then you've got a big advantage as there's so much sun! A normal magnifying mirror is not the way to go as it's hard to scale up. The alternatives are a Fresnel lens or a focussed mirror array, both of which can generate enough heat over a small area to melt steel. Putting the target slightly off the focal point will give lower heat over a larger area although if you're looking to run a turbine on a continuous basis it would have to be on a small scale as it takes a surprising amount of energy to get water from nearly boiling to steam.THIS CHAP is talking about heating a pool with a large Fresnel lens and HERE is information about the construction of a solar mirror array. (There's a really good video of one of these melting various items but I can't find it at the moment.)
Select as Best AnswerUndo Best Answer
If this is a serious project then using the focussed rays to power a Stirling engine would be a more efficient way to do this. This uses the temperature differential directly rather than using the heat to generate steam. Of course, with any of these methods you'd also need some way of tracking the sun to keep the rays focussed at the right point.
It's possible just not practical. It would take a lot of magnifying glasses to get even a gallon of water to start boiling. Not to mention having to track the sun to keep it all focused. This kind of thing is done is some places. They typically involve a very large array of mirrors that reflect the sun light onto a tingle tower where the boiler is at. We are talking several acres here.
instead of boiling the whole gallon why can't we focus the light only on the pipe (coated black/dark)whose diameter equalsthe diameter of spotted light.
How big of a lens do you plan to use? You get the most heat the more focused the beam is. But the more focused it is the smaller the point of contact is. A few pin pricks on the pipe won't be enough to boil the water. Go ahead and play around with it and see if you can get it hot enough.