If the heat spiral heat exchanger is set up properly at the base of the sewer stack, the top portion of the exchanger will be hotter then the bottom. You should see a 15 to 25 deg drop in the temp from top to bottom depending on the temperature differential.
In our case the heat exchanger preheats our well water going to our 60 gallon hot water tank. We have five people taking showers each morning and used to run out of hot water. Now we never run out of hot water and our electric bills are down better then $30 each month since install. One can argue the merits of the system but my experience is the system works as shown and reported in the DOE studies. With the tax credit of $190 we received the unit cost us $195 making our payback less then 1 year. John -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Chip Mefford Sent: Thursday, October 13, 2005 8:29 AM To: Biofuel@sustainablelists.org Subject: Re: [Biofuel] Grey water heat recovery and low techSolar collectors???? Zeke Yewdall wrote: > The heat exchanger path for the incoming cold water is indeed much > smaller with a higher pressure loss (usually, a small spiral tube > wrapped around the greywater drain pipe), however it is clean water, > and is no different than the heat exchanger for any on demand water > heater. > ---------------------------------------------------------- Just a quick note: I considered, then dismissed the spiral wrap in favor of a multi-tube manifold, thus: /-----------------\ ->-------------------->- \------------------/ (sorry but that's the idea) soldered to the underside of the copper drainpipe, as it occured to me that there isn't going to be a whole lot of warm water on the top of the drain pipe where it runs near-horizontal, (slowing the drain to recover more energy) before dropping off vertically. If I spiral wrapped the drain pipe, I'd be putting what heat I recover to work warming the colder side of the pipe, and might end up with a warmer drain pipe with a more even heat distribution, but no real gain of heat into the intake path. _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/ _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
