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Heats my laundry room for free Attached Images
Reply:Good job! I love ideas like this. My Dad plumbed a system in that pulled water from the well/reserve tank and ran it through the firebox in his wood stove then ran the prewarmed water into the hot water heater....saved him a noticible amount on his electricity bill. Welcome to the board.If you don't want to stand behind our Troops, feel free to stand in front of them.
Reply:I've been to Arkansas.  What are you going to do in the summer time?
Reply:Nice work, very clever.  Have you seen designs like this before?  Are there any concerns you know of as far as messing up the draw and hence the combustion?
Reply:My furnace has some little in-line electric fan that switches on when the furnace fan kicks on to evacuate the exhaust...I am guessing because my exhaust vent is not near the peak of the roof and draw might be a problem...but, anyway...does your exhaust vent with or without a fan-assist?Smithboy...if it ain't broke, you ain't tryin'.
Reply:Originally Posted by SWellsGood job! I love ideas like this. My Dad plumbed a system in that pulled water from the well/reserve tank and ran it through the firebox in his wood stove then ran the prewarmed water into the hot water heater....saved him a noticible amount on his electricity bill. Welcome to the board.
Reply:We sweat. What did you do when you were here?
Reply:Originally Posted by pulserNice work, very clever.  Have you seen designs like this before?  Are there any concerns you know of as far as messing up the draw and hence the combustion?
Reply:Originally Posted by smithboyMy furnace has some little in-line electric fan that switches on when the furnace fan kicks on to evacuate the exhaust...I am guessing because my exhaust vent is not near the peak of the roof and draw might be a problem...but, anyway...does your exhaust vent with or without a fan-assist?
Reply:Update - forgot to do this when i finished the project Attached ImagesA butterfly without wings, is just an ugly bug
Reply:Originally Posted by pulserNice work, very clever.  Have you seen designs like this before?  Are there any concerns you know of as far as messing up the draw and hence the combustion?
Reply:This is a forced draft system with a pre and post ignition purge.A butterfly without wings, is just an ugly bug
Reply:Do you have an idea what your temps are after the economizer, to prevent condensation in your flue?
Reply:No, but i don't worry about it because "This is a forced draft system with a pre and post ignition purge."It is getting cold enough that i will probably start the furnace next week.  I'll check the temps then.A butterfly without wings, is just an ugly bug
Reply:So your saying cold air and water vapor from combustion doesn't lead to condensation if you are running a forced draft system? I'm not saying you will have it, because without knowing what kind of heat transfer you're getting on your heat exchanger and the in/out temps, you're really shooting in the dark.
Reply:I'm not Saying anything!  As the hot gas moves through the exchanger some vapor will probably condense out.  So what?  the velocity of the warm forced air will push most of it out the stack and will dry up what little is left when the combustion cycle sops.A butterfly without wings, is just an ugly bug
Reply:Where are you getting cold air?A butterfly without wings, is just an ugly bug
Reply:Cold air is anything less than the temperature required to prevent condensation, which will occur at some temp below 212 degrees or so. In regards to flue gases, that's cold unless you have a condensing furnace, IE high efficiency which is purpose built to condense the flue gases. That's what I mean by cold.So you'll dry up whatever moisture is in there eventually. The whole point of this is that the condensation from the combustion is corrosive. If you dry up the water, you still leave behind the corrosive deposits, which accumulate over time and become more corrosive when they get wet.Your chimney....., not mine. If you aren't worried in the slightest, neither am I. I'm just pointing out a fundamental fact of condensing your flue gases in a furnace/chimney that isn't designed for it.Like I said though, you might be fine, just pointing out something important if you may be concerned about rusty duct work and degrading the masonry if it's brick.
Reply:Hey , I am not an engineer and don't have a PHD.  the chimny is stainless and if i have to replace the pipe every 5 years then i still saved a bundel on gas.A butterfly without wings, is just an ugly bug
Reply:Fair enough. I'm not questioning the design, just asking a fundamental. I didn't want this to be a protracted debate anyway. My line of work is running big boilers, I was just curious if you'd thought about it.
Reply:Im just assuming: using natural draft off the heat exchanger, rising heat goes up the plenum, kicks the thermostat / fan on?I too, would be interested at the difference in exhaust temps.  After all YOU paid to make that exhaust hot, may as well collect the heat off it.What's that other exhaust pipe there?  I guess a water heater??  Looks like another potential heat reclaim job to be had there.
Reply:You  are correct, rising heat goes up the plenum, kicks the thermostat / fan on.I.ll check and post the temps next week when I turn the system on.  I do know that with no air flow the exchanger temp is 140º F.The other pipe is in fact the water heater. i haven't done anything with it because it is natural draft and  haven't figured out a work around for the condensate problem.A butterfly without wings, is just an ugly bug
Reply:Love it! Is the second to last picture the final state? If so, it wouldn't be to code around here as there is too little distance between wood and the exhaust. From what I'm seeing on the photo, that is.I wish there was more of your kind out there. Holger
Reply:What wood?   Oooooh! -  You are looking at the wood grained aluminum.A butterfly without wings, is just an ugly bug
Reply:Not to hijack your thread, but a friend and I did something similar with his tankless water heater. The directions said "Any attempt to make this unit more efficient will void warranty."  Which we took as "this unit can be made more efficient"  If you search for a thread "how to void a warranty"  you'll see it.But it's this, an oil cooler heat air/liquid heat exchanger in a stainless housing.  The exhaust from the heater passes over the exchanger, water passes thru the exchanger - preheating the water into the heater.  If yours is a tanked unit, ...might have to do more engineering to get it to work.  In our system... the condensate stayed in the stainless box, in which we put a drain.  Dribble the drippings over some limestone rock and let it go down the drain.Thanks for the update on this.Originally Posted by Magnetic MechanicWhat wood?   Oooooh! -  You are looking at the wood grained aluminum.
Reply:Originally Posted by slamdvw The directions said "Any attempt to make this unit more efficient will void warranty."  Which we took as "this unit can be made more efficient"
Reply:I too, would be interested at the difference in exhaust temps.  After all YOU paid to make that exhaust hot, may as well collect the heat off it.TEMPS:                                in               outBefore duct fan        656º F             271º FAfter duct fan          656º F             217º FA butterfly without wings, is just an ugly bug
Reply:That was supposed to look like this Attached ImagesA butterfly without wings, is just an ugly bug
Reply:I cant see the pictures well enough to tell what is going on here.This is an exchanger on the vent? And it is piped to the combustion air? What type of gas furnace? (Brand, model) I am with the previous poster. The vents are sized for btu output...  to prevent condensation of combustion gasses, among other things. Maybe a drain would help, but still you have changed the required vent sizing by lowering the "furnace output".Have an HVAC inspector check out this setup and see what they say. ( He will call the gas supplier and have you cut off until  it is put back to code)This might not be worth savings in gas or propane. Carbon monoxide aint good fer ya.
Reply:Exchanger is on exhaust side.have not changed the size of  anything.Rheem mo#  RPGN 12 EARJRHey, what can I tell you no CO and the exhaust is dry'A butterfly without wings, is just an ugly bug
Reply:Originally Posted by greyHave an HVAC inspector check out this setup and see what they say. ( He will call the gas supplier and have you cut off until  it is put back to code)
Reply:Hey guys, don't get me wrong. I do appreciate the feedback.My son (the mechanical engineer) will be home for Thanks-givng, and he will thoroughly check it out.A butterfly without wings, is just an ugly bug
Reply:Me personally... I'd trust the newly added heat exchanger to be more leak free than the exhaust pipe it's connected to.Get a couple of good CO detectors and be done with it.The water heater, I am guessing has a vent hood on it.  An open place where the tank don't seal against the exhaust, but is mixed with cooler air.  Say a big fat bird lands on the 'code inspected' exhaust.  The furnace kicks on with it's fan forced exhaust...  ( see where this is headed?? ).If a person got creative they could modify a CO detector to shut off the furnace in the event of a detection event.
Reply:I think this is a great idea as long as you understand what is going on, and use common sense. I have been kicking around the idea of doing this exact same thing with the dryer vent. There is a hell of a lot of heat going out and heating the great out doors. I might have to rig something up this winter. Only thing with the dryer vent is you are going to get a lot of water so I will have to rig up some kind of drain. -DanOwnerDW Metalworks LLCMiller Trailblazer 302Miller 8RC FeederMiller Passport PlusMiller Dynasty 200 DX W/Coolmate 1Hobart Handler 135Hypertherm PowerMAX 30Smith O/A Torch SetPlus much much more
Reply:Originally Posted by Magnetic Mechanichave not changed the size of  anything.
Reply:Vents are sized to the btu in put of a fuel burning device.  If it's a 100k input, 80k out, or a 100k in  with 20kout, the exhaust is still the same size ( same amount of fuel being burned )... the output is dependent on how efficient the heat exchanger is.If he was changing the fuel jets, he'd have to change exhaust size.  Seeing as he's still burning the same amount of fuel, nothing about the furnace has changed, except for the efficiency.
Reply:Originally Posted by slamdvwVents are sized to the btu in put of a fuel burning device.  If it's a 100k input, 80k out, or a 100k in  with 20kout, the exhaust is still the same size ( same amount of fuel being burned )....
Reply:Well, Paul didn't make it for thanksgiving, but did manage to stop here this weekend on his way to Romania.. After inspecting and measuring the unit he got out the calculator, consulted his steam tables, chemestry book. took manometer readings did some stuff with dew points....Anyway, he said-  "go with it"  "shouldn't have any problems."  So that is what I'm going to do.A butterfly without wings, is just an ugly bug
Reply:Man, you got set up just in time!I don't know if the same cold front hit you that just dropped down into OK, but I bet the temp dropped 30 degrees within an hour.  Complete wind shift, and sleet startin' now.  Stay warm"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Iiiiiittttsss  Commlig>A butterfly without wings, is just an ugly bug
Reply:Time for some hot cocoa or hot chocolate!  Stay warm. It's a balmy 40 degrees here in Columbia,SCIf I knew that I was going to live this long, I would have taken better care of myself
Reply:Originally Posted by Happy BobTime for some hot cocoa or hot chocolate!  Stay warm. It's a balmy 40 degrees here in Columbia,SC