Re: [Biofuel] Polaris as heat exchanger (was solar heat exchanger...)
I don't know Zeke; Does anybody on the list know the answer? I should say that the info I got was from a student who worked in a co-op job installing solar systems for the summer. I have not verified it, although I have no reason to doubt it, and cannot clarify the issue at this point, nor do I have time to persue it. Anyone? Joe Zeke Yewdall wrote: Do they make a distinction between propylene glycol, which is actually used as an ingredient in food, and ethlyene glycol, which is poisonous? We only use propylene glycol solution now, but I wonder if this requirement is still from back in the 70's and early 80's when various stuff (ethylene glycol, bray oil, silicon oil, various alcohols, etc), were used, that you definitely didn't want to get in potable water. Zeke On 9/29/05, Joe Street <[EMAIL PROTECTED]> wrote: Hi Stan; Well you can't get better contact than that! I was told that here in Canada you can't do that for pre-heating domestic water. Aparently if there is glycol in the solar array loop then the heat exchanger must either be stainless or double walled where it contacts potable water. Maybe that was why I made the assumption that I did. Doh! Anyways good luck with it. I'm keen to hear how well it works. Joe Stanley baer wrote: I plan to run the water directly through the flue, the condensing (outlet) end of the flue already has a pipe thread and the plate I made to cover the burner end has a nipple welded on to it. stan Joe Street wrote: One thing you might consider is a way to enhance the thermal transfer efficiency by lowering the thermal resistance. If you plan to run copper pipe through the flue consider attaching it to the surface. I have used metal filled epoxy to glue copper tubing to stainless. It worked well. I was using this as a condenser in a home made soxhlet. In your case there may be a problem with mismatches in the coefficient of thermal expansion between the copper, the epoxy and the iron of the tank which may crack the epoxy (I am thinking outloud and do not know for sure but it is a possiblility). I think the glass transition temperature of the epoxy would be somewhere around 80 deg C or so but you may be ok fer a domestic hotwater application. If I was doing this I would line the surface of the flue with copper pipes glued in and then fill the hollow space remaining in the center with glass fiber to eliminate convective air currents up the middle which would rob heat from the system.. Just a thought. Joe ___ 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/ ___ 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/
Re: [Biofuel] Polaris as heat exchanger (was solar heat exchanger...)
Do they make a distinction between propylene glycol, which is actually used as an ingredient in food, and ethlyene glycol, which is poisonous? We only use propylene glycol solution now, but I wonder if this requirement is still from back in the 70's and early 80's when various stuff (ethylene glycol, bray oil, silicon oil, various alcohols, etc), were used, that you definitely didn't want to get in potable water. Zeke On 9/29/05, Joe Street <[EMAIL PROTECTED]> wrote: > Hi Stan; > > Well you can't get better contact than that! I was told that here in > Canada you can't do that for pre-heating domestic water. Aparently if there > is glycol in the solar array loop then the heat exchanger must either be > stainless or double walled where it contacts potable water. Maybe that was > why I made the assumption that I did. Doh! > Anyways good luck with it. I'm keen to hear how well it works. > > Joe > > Stanley baer wrote: > > I plan to run the water directly through the flue, the condensing (outlet) > end of the flue already has a pipe thread and the plate I made to cover the > burner end has a nipple welded on to it. > > stan > > > Joe Street wrote: > > One thing you might consider is a way to enhance the thermal transfer > efficiency by lowering the thermal resistance. If you plan to run copper > pipe through the flue consider attaching it to the surface. I have used > metal filled epoxy to glue copper tubing to stainless. It worked well. I > was using this as a condenser in a home made soxhlet. In your case there > may be a problem with mismatches in the coefficient of thermal expansion > between the copper, the epoxy and the iron of the tank which may crack the > epoxy (I am thinking outloud and do not know for sure but it is a > possiblility). I think the glass transition temperature of the epoxy would > be somewhere around 80 deg C or so but you may be ok fer a domestic hotwater > application. If I was doing this I would line the surface of the flue with > copper pipes glued in and then fill the hollow space remaining in the center > with glass fiber to eliminate convective air currents up the middle which > would rob heat from the system.. > Just a thought. > > Joe > > > > ___ > 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/ > > > > ___ 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/
Re: [Biofuel] Polaris as heat exchanger (was solar heat exchanger...)
Hi Stan; Well you can't get better contact than that! I was told that here in Canada you can't do that for pre-heating domestic water. Aparently if there is glycol in the solar array loop then the heat exchanger must either be stainless or double walled where it contacts potable water. Maybe that was why I made the assumption that I did. Doh! Anyways good luck with it. I'm keen to hear how well it works. Joe Stanley baer wrote: I plan to run the water directly through the flue, the condensing (outlet) end of the flue already has a pipe thread and the plate I made to cover the burner end has a nipple welded on to it. stan Joe Street wrote: One thing you might consider is a way to enhance the thermal transfer efficiency by lowering the thermal resistance. If you plan to run copper pipe through the flue consider attaching it to the surface. I have used metal filled epoxy to glue copper tubing to stainless. It worked well. I was using this as a condenser in a home made soxhlet. In your case there may be a problem with mismatches in the coefficient of thermal expansion between the copper, the epoxy and the iron of the tank which may crack the epoxy (I am thinking outloud and do not know for sure but it is a possiblility). I think the glass transition temperature of the epoxy would be somewhere around 80 deg C or so but you may be ok fer a domestic hotwater application. If I was doing this I would line the surface of the flue with copper pipes glued in and then fill the hollow space remaining in the center with glass fiber to eliminate convective air currents up the middle which would rob heat from the system.. Just a thought. Joe ___ 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/
Re: [Biofuel] Polaris as heat exchanger (was solar heat exchanger...)
I plan to run the water directly through the flue, the condensing (outlet) end of the flue already has a pipe thread and the plate I made to cover the burner end has a nipple welded on to it. stan Joe Street wrote: One thing you might consider is a way to enhance the thermal transfer efficiency by lowering the thermal resistance. If you plan to run copper pipe through the flue consider attaching it to the surface. I have used metal filled epoxy to glue copper tubing to stainless. It worked well. I was using this as a condenser in a home made soxhlet. In your case there may be a problem with mismatches in the coefficient of thermal expansion between the copper, the epoxy and the iron of the tank which may crack the epoxy (I am thinking outloud and do not know for sure but it is a possiblility). I think the glass transition temperature of the epoxy would be somewhere around 80 deg C or so but you may be ok fer a domestic hotwater application. If I was doing this I would line the surface of the flue with copper pipes glued in and then fill the hollow space remaining in the center with glass fiber to eliminate convective air currents up the middle which would rob heat from the system.. Just a thought. Joe ___ 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/
Re: [Biofuel] Polaris as heat exchanger (was solar heat exchanger...)
One thing you might consider is a way to enhance the thermal transfer efficiency by lowering the thermal resistance. If you plan to run copper pipe through the flue consider attaching it to the surface. I have used metal filled epoxy to glue copper tubing to stainless. It worked well. I was using this as a condenser in a home made soxhlet. In your case there may be a problem with mismatches in the coefficient of thermal expansion between the copper, the epoxy and the iron of the tank which may crack the epoxy (I am thinking outloud and do not know for sure but it is a possiblility). I think the glass transition temperature of the epoxy would be somewhere around 80 deg C or so but you may be ok fer a domestic hotwater application. If I was doing this I would line the surface of the flue with copper pipes glued in and then fill the hollow space remaining in the center with glass fiber to eliminate convective air currents up the middle which would rob heat from the system.. Just a thought. Joe Zeke Yewdall wrote: On the positive side, circulating hot water through the flue should increase heat transfer rate considerably compared to the original design as an air to liquid heat exhanger. But the hot water from the collectors are also much lower temperature than flue gasses. I'm interested in hearing the results too. On 9/28/05, Tom Scheel <[EMAIL PROTECTED]> wrote: The Polaris flue is a 2" diameter heat exhanger. That is how the Polaris achieves 95%+ efficiency ratings. That is the good news. The bad news is that the source of that heat is that 100k+ BTU gas burner you tossed out. So you will not get the short recovery times. What is your square footage of collector? (you would need roughly ten 4'X10' panels to match the oringal 100k BTU (not suggesting you do that, especially given that your heat exchanger can't exchange that much heat)). You will need to move more GPM (gallons per minute) than "normal" becuase of the large flue size. And your post identified the biggest problem, your surface area per volume is low (surface area=good). All of that said, I can't say it won't work. Please update on your progress/results. Hi I have been following this thread. My plan for the heat exchange between the solar collector and the potable hot water system is to modify a discarded gas fired Polaris hotwater heater. The tank of this hotwater heater is made of stainless. I have pulled out all the gas burner guts out of it, made a plate to close off the bottom of the heater end. I hope to acheive the heat tranfer by circulating hot water from the collectors throught the flue of this tank. this setup does not leak but I am not sure how well it will work as a heat exchanger as the surface area of the flue is not all that large. stan Radiance Heating and Plumbing, Inc. (ROC 204149,204150) Tom Scheel 928-380-6294 ___ 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/ ___ 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/
Re: [Biofuel] Polaris as heat exchanger (was solar heat exchanger...)
On the positive side, circulating hot water through the flue should increase heat transfer rate considerably compared to the original design as an air to liquid heat exhanger. But the hot water from the collectors are also much lower temperature than flue gasses. I'm interested in hearing the results too. On 9/28/05, Tom Scheel <[EMAIL PROTECTED]> wrote: > The Polaris flue is a 2" diameter heat exhanger. That is how the Polaris > achieves 95%+ efficiency ratings. That is the good news. The bad news is > that the source of that heat is that 100k+ BTU gas burner you tossed out. So > you will not get the short recovery times. What is your square footage of > collector? (you would need roughly ten 4'X10' panels to match the oringal > 100k BTU (not suggesting you do that, especially given that your heat > exchanger can't exchange that much heat)). You will need to move more GPM > (gallons per minute) than "normal" becuase of the large flue size. And your > post identified the biggest problem, your surface area per volume is low > (surface area=good). All of that said, I can't say it won't work. Please > update on your progress/results. > > Hi > > I have been following this thread. My plan for the heat exchange > between the solar collector and the potable hot water system is to > modify a discarded gas fired Polaris hotwater heater. The tank of this > hotwater heater is made of stainless. I have pulled out all the gas > burner guts out of it, made a plate to close off the bottom of the > heater end. I hope to acheive the heat tranfer by circulating hot water > from the collectors throught the flue of this tank. this setup does not > leak but I am not sure how well it will work as a heat exchanger as the > surface area of the flue is not all that large. > > stan > > > Radiance Heating and Plumbing, Inc. (ROC 204149,204150) > Tom Scheel > 928-380-6294 > ___ > 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/
Re: [Biofuel] Polaris as heat exchanger (was solar heat exchanger...)
The Polaris flue is a 2" diameter heat exhanger. That is how the Polaris achieves 95%+ efficiency ratings. That is the good news. The bad news is that the source of that heat is that 100k+ BTU gas burner you tossed out. So you will not get the short recovery times. What is your square footage of collector? (you would need roughly ten 4'X10' panels to match the oringal 100k BTU (not suggesting you do that, especially given that your heat exchanger can't exchange that much heat)). You will need to move more GPM (gallons per minute) than "normal" becuase of the large flue size. And your post identified the biggest problem, your surface area per volume is low (surface area=good). All of that said, I can't say it won't work. Please update on your progress/results. HiI have been following this thread. My plan for the heat exchange between the solar collector and the potable hot water system is to modify a discarded gas fired Polaris hotwater heater. The tank of this hotwater heater is made of stainless. I have pulled out all the gas burner guts out of it, made a plate to close off the bottom of the heater end. I hope to acheive the heat tranfer by circulating hot water from the collectors throught the flue of this tank. this setup does not leak but I am not sure how well it will work as a heat exchanger as the surface area of the flue is not all that large.stanRadiance Heating and Plumbing, Inc. (ROC 204149,204150)Tom Scheel928-380-6294___ 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/
