Even today most consumer's computers emit under 100W average (not counting monitor and peripherals - CPU, graphics, chipset), due to power saving technologies that allow for CPU throttling, etc. You'd have to purposefully run your machine very hard 100% of the time in order to get anywhere near 400W of heating from it, and most consumer machines still only ship with 400W power supplies that really only manage about 300W constant and 400W peak. In other words, your back of the napkin calculations are overestimating heat output. If your particular rig is high end, then you may have more heat output. Most water heating elements are rated in kW, though. I would be surprised if hooking it up as a preheater noticably reduced your water heating bill. You'd probably have a much greater effect by hooking up the heat exchanger to the sewage line and recovering waste heat from showers, washers, etc to preheat your water. -Adam On 2/19/08, Tobias Gogolin wrote: > I've been shopping for new computers: CPU, Grapics and motherboards > I noticed that lots of motherboards and heatsinks now use copper heat pipes, > I assume those are made from solid copper! > CPUs range from 60-120 Watts; Graphics Processors can consume even more, I'm > not sure about the motherboard power consumption, > Anyhow 400 Watts is probably a reasonable sum, and I figure if those copper > pipes where hollow and connected in series water could be piped through them > and help to heat water for residential applications! > I suspect that the actual change of information entropy is a minute effect > in comparison to the power consumed due to resistance of conductors and > switches! > > So it may be interesting to by design harvest the energy the computer > converts and preheat water! > Just wonder what y'all think!? > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Moving in southeast Michigan? Buy my house: http://ubasics.com/house/ Interested in electronics? Check out the projects at http://ubasics.com Building your own house? Check out http://ubasics.com/home/ -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist