Thread: Solar Panel Workshop sept 2007

So many cool things to build ... so little time!

It sounds like it may be a good idea for the DIYer, but at £150 plus the time involved, I'd want some independent verification, under controlled conditions to see just how effective they are at reducing energy consumption.
Don't forget that for about $2,000 you can get an entire set up using optimum materials from companies that have done a lot of research into the subject. This includes the tank as well, so if you need to replace your tank anyway, then you're only paying about $1,000 for the solar technology. I'd guess that they're a lot more efficient than a home made job.

Another point with this DIY set up is, how do you transfer the water to the tank?
With most professional set ups, the tank is mounted on the roof above the panel. As the water heats and expands, it rises to the tank, and cold water from the tank descends to the panel.
With the panel mounted on the roof, and the tank at floor level, how are you going to circulate the water? If it is just connected to the cold water inlet, then it will only heat the very small amount of water that's in the pipe in the panel, and this will cool down again quite quickly as the sun sets, or is obscured by dense cloud cover. It would also cool down a lot just traveling through the cold pipe down to the tank.

Without some sort of pump (using more energy), I don't see how the water circulates to the panel.

Edit: And don't forget that in Australia, only a licensed plumber is allowed to work on mains pressure pipes. So if you're going to follow all the rules , then it will cost you a lot more than the equivalent of £150.