EcoRenovator  

Go Back   EcoRenovator > Improvements > Conservation
Advanced Search
 


Blog Register 60+ Home Energy Saving Tips Recent Posts Search Today's Posts Mark Forums Read


Reply
 
Thread Tools Display Modes
Old 03-15-13, 11:40 AM   #11
Drake
DIY Guy
 
Join Date: Jan 2011
Location: Mpls,MN
Posts: 315
Thanks: 2
Thanked 17 Times in 17 Posts
Default

The sand in the tube helps prevent it from "kinking" and bending smoothly, as you say just "flattening could be a positive if you could get it to do just that and not kink.

I'm sure all of us DIY'ers have experienced the "I'd do it different if I ever did it again" but I applaud the first attempt of all of us and the sharing of that effort, for it is from those that the rest of us can benefit in our projects by building on.

Drake is offline   Reply With Quote
Old 03-15-13, 03:56 PM   #12
Exeric
Apprentice EcoRenovator
 
Join Date: Aug 2012
Location: California
Posts: 274
Thanks: 19
Thanked 37 Times in 28 Posts
Default

I agree with Drake that the experience of others benefits us all. One thing that was really good to hear was that Steve layed the tubing on its side and got really good results. All the manufactures claim that you have to have it vertically to get good even capillary action. That doesn't make sense to me. If you have it near horizontal instead you won't get that smooth action but it seems to me the results will even out in the end. The water will run slower so it seems like the heat would transfer just as well. It would go to the bottom of the tube and then conduct from the bottom to the entire circumference because copper is a good heat conductor. Steve's empirical results are encouraging because I don't have that much of a vertical drop to work with.

I'm also thinking of doing the same thing with the dishwasher. Since my house is pretty much torn apart right now I can put in a drain line for it that is separate from the kitchen sink drain line. The only problem I see is how to get a P-trap in there that is close enough to the wall to not interfere with the dishwasher.
Exeric is offline   Reply With Quote
Old 03-15-13, 05:05 PM   #13
Exeric
Apprentice EcoRenovator
 
Join Date: Aug 2012
Location: California
Posts: 274
Thanks: 19
Thanked 37 Times in 28 Posts
Smile Oops

I was thinking that I would need a separate drain line for the dishwasher because if it was hooked to the kitchen sink drain line then if cold water was drawn it would send cold water to the water heater/storage tank. That wouldn't happen. Water only goes into the tank when water is used and there is more room. If you draw cold water from the kitchen sink no room is made for more water to enter the hot water heater so that wouldn't be a problem for a heat exchanger.

That makes life simpler for me.
Exeric is offline   Reply With Quote
Old 03-15-13, 05:19 PM   #14
Exeric
Apprentice EcoRenovator
 
Join Date: Aug 2012
Location: California
Posts: 274
Thanks: 19
Thanked 37 Times in 28 Posts
Default

It would make a "whole house" grey water heat exchanger make sense. Since the only time you have room in the water heater is when you use hot water the only time the heat exchanger would add water is when there is warm heat exchanger water to be added. The only exception would be a bathtub or sink full of hot water that does not drain while the water is still hot. If you had a dishwasher the kitchen sink wouldn't be a problem. The bathtub would be though. Maybe it would be best to have everything except the bathtub on a whole house exchanger and have the bathtub join downstream of it. (Assuming the use of a dishwasher)
Exeric is offline   Reply With Quote
Old 03-15-13, 08:19 PM   #15
Drake
DIY Guy
 
Join Date: Jan 2011
Location: Mpls,MN
Posts: 315
Thanks: 2
Thanked 17 Times in 17 Posts
Default

Exeric, that is the question/s that I am pondering now as I am favoring a "whole house tank" approach for plumbing/space consideration as well that can be in the basement. Whether to just recover the higher temp gray water when use incoming and outgoing are at or close to same time(I plan to audit a dishwasher cycle to see if hot drain water is draining at same time more hot water is going in, as in a shower). An insulated holding tank, though having heat loss over time, would work better where incoming demand isn't at same time as leaving.
Drake is offline   Reply With Quote
Old 03-16-13, 03:32 AM   #16
JYL
Heat recoverer
 
Join Date: May 2011
Location: Quebec, Canada
Posts: 17
Thanks: 0
Thanked 2 Times in 2 Posts
Default

Whole house Heat recovery work pretty well.

The only potential inconvenient with the technology are the following :
a) For your shower, you might prefer to get a "Thermostatic compensation valve" to kept the temperature consistent... these are generally a little more expensive starting at about 250$ for the cheapest model. The often seen Pressure compensation valve will fail to maintain a consistent temperature. In Home depot, you might find 1 or 2 "Thermostatic Compensation valve" for 100 of Pressure compensation.

b) Sometime, you might notice that your cold water is lukewarm at some of your faucet (Ex: Kitchen). However, this is seldom really noticed or a real problem. The water is really not that hot.

c) With most GFX technologies, their is very little recovery for batch "Usage" such as bath, home dishwasher, cloth washer, etc...

d) So, at the end, unless you have several teenager in the house, the return on investment for a commercial installation is very long. (How much hot water should you safe to offset a 800$ to 1000$ GFX installation).

----------------
Horizontal vs Vertical for the sewer pipe: You can do heat recovery with both type. However, Vertical generally win by a very wide margin.

The reason explaining the large "advantage" of the vertical pipe is in the turbulence of the water. The more turbulence, the better heat transfer you get. See "Reynold Number" (Heat transfer coefficient - Wikipedia, the free encyclopedia)

When the pipe is vertical, the water stick to the surface of the pipe because of the movement of the air. So, vertical drop make a thin film of water all around the copper sewer pipe -- and that water is more turbulent because of the acceleration made possible by the gravity..
JYL is offline   Reply With Quote
Old 03-30-13, 08:12 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 33 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
Old 03-31-13, 12:29 PM   #18
Mikesolar
Master EcoRenovator
 
Mikesolar's Avatar
 
Join Date: Aug 2012
Location: Toronto
Posts: 958
Thanks: 40
Thanked 158 Times in 150 Posts
Default

I have a GFX on my stack in the basement. It really needs the speed of the heat transfer that copper gives to work properly and the copper is flattened to be rectangular. The surface area is quite important because, as said above, it only works during the shower so waiting won't be effective.
Mikesolar is offline   Reply With Quote
Old 03-31-13, 02:47 PM   #19
NiHaoMike
Supreme EcoRenovator
 
NiHaoMike's Avatar
 
Join Date: Oct 2008
Location: Austin, TX
Posts: 1,127
Thanks: 15
Thanked 247 Times in 233 Posts
Default

Quote:
Originally Posted by Drake View Post
The sand in the tube helps prevent it from "kinking" and bending smoothly, as you say just "flattening could be a positive if you could get it to do just that and not kink.

I'm sure all of us DIY'ers have experienced the "I'd do it different if I ever did it again" but I applaud the first attempt of all of us and the sharing of that effort, for it is from those that the rest of us can benefit in our projects by building on.
Maybe use salt instead of sand? Then when you flush it out with water, whatever remains would dissolve.
__________________
To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...
NiHaoMike is offline   Reply With Quote
Old 04-01-13, 08:01 AM   #20
razor02097
Helper EcoRenovator
 
Join Date: Mar 2013
Location: 245862
Posts: 43
Thanks: 12
Thanked 3 Times in 3 Posts
Default

I like the idea of wrapping the pipe around the drain. It makes a lot of sense... Makes you wonder why manufacturers don't offer it built in?

razor02097 is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 11:18 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Ad Management by RedTyger
Inactive Reminders By Icora Web Design