I used to work at the home depot. It wasn’t the most challenging task to work in the plumbing department, but it did afford me some interesting learning opportunities. I had a few people come in looking for parts to build a DIY solar pool heater. After the first three or four, I was pretty good at remembering the parts needed from the previous customers experience. That was always a fun one.
But there was another section of the department that interested me greatly. It was the Zurn Pex Tubing section. If you have ever worked with Pex tubing, maybe you can attest to the splendor of the product. There is no sweating (that’s fancy plumber talk for soldering pipe and fittings together), no heat at all actually, just some fancy clamp rings and brass fittings. The tubing is used to deliver pressurized water, one type is used for radiant floor heating, and the other is for drinking water. Its all the rage in new home construction, especially when I was there and copper prices were hitting all time highs. That was years ago so I can’t even imagine what copper costs now when people are willing to steal the wiring from street lamps for scrap.
One of the most interesting parts of Zern Pex tubing was that it could be used for radiant floor heating, and that system could be supplied with hot water in several ways. Another employee talked at great length of the flexibility of a radiant floor heating system with Zern. He told me great stories of how an electric water heater could be used to efficiently heat the water for the tubing. Lately I’ve been imagining such a system in combination with a solar water heater.
It was then that I stumbled upon a really interesting article on Make Magazine where some one had created a parabolic focused mirror array out of an old satellite dish. The dish is twelve feet in diameter and they used several mirrors broken into pieces and carefully arranged to focus sunlight at a fixed point about five feet above the center of the dish. The results were astounding. There are plenty of videos on youtube.com featuring chicken roasted to charcoal on the dish side yet still frozen on the other side. The focal point quickly raises the temperature of an oven thermometer to the max reading.
That’s when it hit me, why not use such a device to focus sunlight on a pipe of water to heat your home in the winter time? Furthermore, why not use that sunlight to heat water to steam and push it through some sort of electricity generating device that could be used in the summer to reduce your power bill? While we are on the subject, why not use mirrors more in general? Imagine how much more light a solar panel could collect on an overcast day if it had a bunch of mirrors pointed on it! Mirrors are much less expensive than solar panels so it could increase their productivity at a fraction of the cost of adding more solar panels to your array. Maybe we could even make some sort of cold water heat sink for a solar panel at the focal point of such a dish and harness light and heat from the sun.
Call me a crack pot, but I think its a completely possible idea. If anyone has any experience with such an experiment, I would love to see the data and results. A proof of concept is in order for this one, and maybe I will have the time to try it out. Last summer I bought the four foot tall mirror and a glass cutter for about $10 and started cutting the mirror into small squares. I wasn’t able to find a suitable parabolic curve and work was demanding a lot of my time. The project was pushed to the back burner, but I’m going to bring it back to the front very soon. Comments, suggestions, or angry responses?
