View Single Post
Old 03-30-13, 07:12 PM   #17
menaus2
Apprentice EcoRenovator
 
Join Date: Feb 2011
Location: Driftless Region, North America, Earth, Solar System, Orion Arm, Milky Way Galaxy,Virgo Supercluster
Posts: 116
Thanks: 13
Thanked 34 Times in 25 Posts
Default

I've been thinking about grey-water-heat-recovery as well, and it's great to see some sweet projects already completed. I've been thinking a lot about the use of pex-al-pex as a lower cost quick alternative. My solar collector is pex-al-pex, and the heat exchanger on the solar preheat tank is 1" pex so I know the stuff works reasonably well. A system like this whether pex or Cu could considerably improve the performance of my solar preheat tank.

The hypothesis being that with a less expensive material, you can afford to do heat exchange over a larger area; Potentially recovering more total btu's despite being a less conductive material.

Any thoughts on the plausibility of pex as a material for a similar project or is copper just that much of a superior material?

Another thought as far as the best places to locate a heat recovery section would be to look at the piping with a thermal camera. A simple run through of different scenarios would give you an idea of where the heat is distributed in the drain pipe..

... oooooor you could just re-engineer the whole drainpipe so that each waste heat source has it's own vertical drop. All the vertical drainpipes would have a simple electronically controlled valve to route the preheat water to the appropriate drainpipe(s) with available waste heat. Again, what kind of payback are you looking at for the extra complexity and with what kinds of materials? Also to consider is potentially what cost cutting further along in the system will be made possible by excellent performance early on aka "cost tunneling". As an example by implementing excellent heat recovery I could be able to replace a new water heater when it inevitably dies with a much smaller and less expensive model etc... Basically potential synergies, what role would that play?
menaus2 is offline   Reply With Quote