by **DirtpatchSmacky** » Sun Jul 02, 2006 5:34 am

The turbine would have to be geared to such a low ratio as to be allmost useles, there is allmost no pressure behind the water in a downspout, cant think of what the mathematical formulea would be, but something along the lines of gutter mass(if completely full) times resevour mass(water on roof, if constant) times gravity at turbine height. for the turbine to be geared to produce anything but negligble amounts of energy, the resevour mass would have to be along the lines of sustainably holding 40 times the amount the gutter can hold per foot untill it reaches the turbine. so if the gutter, per foot was capable of holding one cubic foot of water the resevour would have to hold 40 cubic feet, then multiply that by the linear feet of the gutter,, say 10 running foot, times 1 cubic gallon per foot, is 10 cubic gallon, so the resevour would have to sustain around 400 cubic foot of water. when the water in the resvour got down to about 100 cubic foot, there wouldnt be enough pressure to power the turbine, if geared to produce noticable amounts of juice.i am far from a mathemetician or energy turbine theorist, so these numbers may be flawed,, but they should be close.