Re: [Biofuel] Double wall heat exchange - Solar Hot Water Heater
Well ASCII isn't always ASCII, the question mark in the sentence Personally I would put my ? (or whatever) on stainless steel... was the monetary symbol for EURO... Sorry for messing up. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Kjell Lofgren Sent: den 28 september 2005 07:19 To: Biofuel@sustainablelists.org Subject: Re: [Biofuel] Double wall heat exchange - Solar Hot Water Heater Ken, do not use PVC for drinking water, the softener DEHP in the PVC material is slowly leaking out and there is also other nonhealthy stuff (chlorine!) in PVC. Personally I would put my ? (or whatever) on stainless steel, 18/8 sounds nice to me, almost beautiful... -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Ken Dunn Sent: den 27 september 2005 21:54 To: Biofuel@sustainablelists.org Subject: Re: [Biofuel] Double wall heat exchange - Solar Hot Water Heater On 9/27/05, Zeke Yewdall [EMAIL PROTECTED] wrote: Well, in this case, there is not supposed to be any heat transfer through the PVC, so I wouldn't be worried about that. I agree that metal would be better, it you can find some large diameter metal pipe for cheap. What about just putting a coil of copper tubing in a big metal trash can? Certainly not elegant, but it would be cheap, and require just about no manufacturing. Well, while I couldn't care much less about the elegance of the installation, my kids are still young and I'd like to find someone to buy my house when I'm ready to move into a smaller space. Also, as I've mentioned several times, I would like to help others with solutions like solar hot water. And frankly, I live in the U.S. where things are supposed to be both sexy and puritanical simultaneously. A big metal trash can is neither. Furthermore, I would like to continue living in the house with my wife once its all said and done. I'm pretty sure that my wife would be just a bit leary of our drinking water getting anywhere near a trash can. Thanks, ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.o rg 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.o rg 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] Double wall heat exchange - Solar Hot Water Heater
Ken, to avoid the tube bending business you canuse a plate heat exchanger - more compact but if DIY you have to do some welding. Cut two equally sizedpieces of *thin* stainless steel plate. Make about twodimples about 2 mm deep on every square 10 cm of the platewith a ball-peen(sp?) hammer (work on a wooden bench!). Weld the two plates together all around the edges with the sides with the raised dimples facing each other. Grind away the weld and cone out openings forthe short pieces of pipes where the fluid goes in and out (on opposite corners). The short pipe pieces arewelded in place. Carefully pressurize the unit with very low air pressure - less than0.05 kg/cm2 - and test for leaks with soap water, remember to use clamps or something to hold the plates together or you end up with a pressurized 'football'! Make two or more of these units and submerge in whatever storage tank you use, you can connect them in series or in parallel as long as you avoid air pockets. The size of the platesis as big as needed butkeep in mind thatthese DIY units are not meant to be used with internal pressure! Pressure can maybe be usedinside the storage tank but the numbers of dimples have to be increased. Also beware of air pressure in large containers - even a small pressure can add up to large forces and even blow the container! Stainless steel rods for welding and a TIG welding equipment is also needed - a skilled TIG welding buddy will make things easier if you don'thave the know-how. -Original Message-From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Ken DunnSent: den 24 september 2005 08:02To: Biofuel@sustainablelists.orgSubject: [Biofuel] Double wall heat exchange - Solar Hot Water HeaterHi all,Sorry for the long subject line but, I thought it may aid in archive searches... Is there a home remedy to creating a double wall heat exchange? I have contemplated buying two sizes of copper tubing, inserting the smaller inside the larger and bending the two simultaneously. I could see how the inner tubing might kink or flatten out but, I think that would be unlikely unless I tried to bend too tight of a radius. Is there a better home-builder solution? Perhaps there is an affordable storage tank commercially available that makes building a backyard heat exchange mute anyway.? I'm going to need to come up with a storage tank anyway. I understand the theoretical pros/cons to internal and external heat exchanges but, what are the real-world practical differences?Thanks a bunch,Take care,Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
Kjell, I will certainly give this a try for my own purposes, it seems simple enough. But, I can operate a TIG and have access to one. Unfortunately, a TIG welder and the associated experience are not widely spread. I do want to keep this project as Appropriate as possible. So, I'm trying to find materials that are as readily available as possible. Also, I plan to use propolene glycol so, there is the issue of double walls. I could certainly adapt this idea accordingly. Its really too bad that brazing the plate together wouldn't be sufficient - that would make it an easier DIY. Thanks a bunch, Take care, Ken On 9/27/05, Kjell Löfgren [EMAIL PROTECTED] wrote: Ken, to avoid the tube bending business you can use a plate heat exchanger - more compact but if DIY you have to do some welding. Cut two equally sized pieces of *thin* stainless steel plate. Make about two dimples about 2 mm deep on every square 10 cm of the plate with a ball-peen(sp?) hammer (work on a wooden bench!). Weld the two plates together all around the edges with the sides with the raised dimples facing each other. Grind away the weld and cone out openings for the short pieces of pipes where the fluid goes in and out (on opposite corners). The short pipe pieces are welded in place. Carefully pressurize the unit with very low air pressure - less than 0.05 kg/cm2 - and test for leaks with soap water, remember to use clamps or something to hold the plates together or you end up with a pressurized 'football'! Make two or more of these units and submerge in whatever storage tank you use, you can connect them in series or in parallel as long as you avoid air pockets. The size of the plates is as big as needed but keep in mind that these DIY units are not meant to be used with internal pressure! Pressure can maybe be used inside the storage tank but the numbers of dimples have to be increased. Also beware of air pressure in large containers - even a small pressure can add up to large forces and even blow the container! Stainless steel rods for welding and a TIG welding equipment is also needed - a skilled TIG welding buddy will make things easier if you don't have the know-how. ___ 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] Double wall heat exchange - Solar Hot Water Heater
Maybe I'm losing my mind but I swear I used to have a kit w/ different head and a long bar that I used to bend copper pipe. I remember it as being very cheap (under 100.00 USD) at someplace like Norther Tool or Harbor Freight. Of cource I haven't done any plumbing in over 20 years - maybe the don't make it any more. -Mike Kjell Löfgren wrote: Ken, to avoid the tube bending business you can use a plate heat exchanger - more compact but if DIY you have to do some welding. Cut two equally sized pieces of *thin* stainless steel plate. Make about two dimples about 2 mm deep on every square 10 cm of the plate with a ball-peen(sp?) hammer (work on a wooden bench!). Weld the two plates together all around the edges with the sides with the raised dimples facing each other. Grind away the weld and cone out openings for the short pieces of pipes where the fluid goes in and out (on opposite corners). The short pipe pieces are welded in place. Carefully pressurize the unit with very low air pressure - less than 0.05 kg/cm2 - and test for leaks with soap water, remember to use clamps or something to hold the plates together or you end up with a pressurized 'football'! Make two or more of these units and submerge in whatever storage tank you use, you can connect them in series or in parallel as long as you avoid air pockets. The size of the plates is as big as needed but keep in mind that these DIY units are not meant to be used with internal pressure! Pressure can maybe be used inside the storage tank but the numbers of dimples have to be increased. Also beware of air pressure in large containers - even a small pressure can add up to large forces and even blow the container! Stainless steel rods for welding and a TIG welding equipment is also needed - a skilled TIG welding buddy will make things easier if you don't have the know-how. -Original Message- *From:* [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of *Ken Dunn *Sent:* den 24 september 2005 08:02 *To:* Biofuel@sustainablelists.org *Subject:* [Biofuel] Double wall heat exchange - Solar Hot Water Heater Hi all, Sorry for the long subject line but, I thought it may aid in archive searches... Is there a home remedy to creating a double wall heat exchange? I have contemplated buying two sizes of copper tubing, inserting the smaller inside the larger and bending the two simultaneously. I could see how the inner tubing might kink or flatten out but, I think that would be unlikely unless I tried to bend too tight of a radius. Is there a better home-builder solution? Perhaps there is an affordable storage tank commercially available that makes building a backyard heat exchange mute anyway.? I'm going to need to come up with a storage tank anyway. I understand the theoretical pros/cons to internal and external heat exchanges but, what are the real-world practical differences? Thanks a bunch, Take care, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
Mike, the bending is not the problem so much as bending a tube inside a tube without the inner tube flattening out or kinking. Though, the more I think about it, the inner tube, being smaller than the outter tube will be less likely to kink than the outter purely by smaller diameter and tighter bend radius. Moreover, I talked to a fellow this weekend that told me to try tightly wrapping the center tube with a heavy gauge, uninsulated wire then insert it into the outter tube, this will make up some difference in size and help to prevent kinking of the inner tube. I'm going to try this along with simply inserting the smaller tube inside the larger and bending. I had considered tube-in-tube-in-tube and running hot propolene glycol and water, in opposite directions, through it. I'm not sure that I'm still going to pursue that route except for experimentation purposes. Take care, Ken On 9/27/05, Mike Weaver [EMAIL PROTECTED] wrote: Maybe I'm losing my mind but I swear I used to have a kit w/ different head and a long bar that I used to bend copper pipe. I remember it as being very cheap (under 100.00 USD) at someplace like Norther Tool or Harbor Freight. Of cource I haven't done any plumbing in over 20 years - maybe the don't make it any more. -Mike Kjell Löfgren wrote: Ken, to avoid the tube bending business you can use a plate heat exchanger - more compact but if DIY you have to do some welding. Cut two equally sized pieces of *thin* stainless steel plate. Make about two dimples about 2 mm deep on every square 10 cm of the plate with a ball-peen(sp?) hammer (work on a wooden bench!). Weld the two plates together all around the edges with the sides with the raised dimples facing each other. Grind away the weld and cone out openings for the short pieces of pipes where the fluid goes in and out (on opposite corners). The short pipe pieces are welded in place. Carefully pressurize the unit with very low air pressure - less than 0.05 kg/cm2 - and test for leaks with soap water, remember to use clamps or something to hold the plates together or you end up with a pressurized 'football'! Make two or more of these units and submerge in whatever storage tank you use, you can connect them in series or in parallel as long as you avoid air pockets. The size of the plates is as big as needed but keep in mind that these DIY units are not meant to be used with internal pressure! Pressure can maybe be used inside the storage tank but the numbers of dimples have to be increased. Also beware of air pressure in large containers - even a small pressure can add up to large forces and even blow the container! Stainless steel rods for welding and a TIG welding equipment is also needed - a skilled TIG welding buddy will make things easier if you don't have the know-how. ___ 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] Double wall heat exchange - Solar Hot Water Heater
Hmm...what if you centered the smaller tube and held it in place with spacers, wax would work, and then filled it with fine grain sand, then bent it? let me know how it goes... -Mike Ken Dunn wrote: Mike, the bending is not the problem so much as bending a tube inside a tube without the inner tube flattening out or kinking. Though, the more I think about it, the inner tube, being smaller than the outter tube will be less likely to kink than the outter purely by smaller diameter and tighter bend radius. Moreover, I talked to a fellow this weekend that told me to try tightly wrapping the center tube with a heavy gauge, uninsulated wire then insert it into the outter tube, this will make up some difference in size and help to prevent kinking of the inner tube. I'm going to try this along with simply inserting the smaller tube inside the larger and bending. I had considered tube-in-tube-in-tube and running hot propolene glycol and water, in opposite directions, through it. I'm not sure that I'm still going to pursue that route except for experimentation purposes. Take care, Ken On 9/27/05, Mike Weaver [EMAIL PROTECTED] wrote: Maybe I'm losing my mind but I swear I used to have a kit w/ different head and a long bar that I used to bend copper pipe. I remember it as being very cheap (under 100.00 USD) at someplace like Norther Tool or Harbor Freight. Of cource I haven't done any plumbing in over 20 years - maybe the don't make it any more. -Mike Kjell Löfgren wrote: Ken, to avoid the tube bending business you can use a plate heat exchanger - more compact but if DIY you have to do some welding. Cut two equally sized pieces of *thin* stainless steel plate. Make about two dimples about 2 mm deep on every square 10 cm of the plate with a ball-peen(sp?) hammer (work on a wooden bench!). Weld the two plates together all around the edges with the sides with the raised dimples facing each other. Grind away the weld and cone out openings for the short pieces of pipes where the fluid goes in and out (on opposite corners). The short pipe pieces are welded in place. Carefully pressurize the unit with very low air pressure - less than 0.05 kg/cm2 - and test for leaks with soap water, remember to use clamps or something to hold the plates together or you end up with a pressurized 'football'! Make two or more of these units and submerge in whatever storage tank you use, you can connect them in series or in parallel as long as you avoid air pockets. The size of the plates is as big as needed but keep in mind that these DIY units are not meant to be used with internal pressure! Pressure can maybe be used inside the storage tank but the numbers of dimples have to be increased. Also beware of air pressure in large containers - even a small pressure can add up to large forces and even blow the container! Stainless steel rods for welding and a TIG welding equipment is also needed - a skilled TIG welding buddy will make things easier if you don't have the know-how. ___ 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] Double wall heat exchange - Solar Hot Water Heater
Ken, why not use straight tubes (if you have the space), one tube length (20 feet?) in one direction and the next tube length running back? You could put your three (four?) tubes into each other both ways and have a U-bend and some interconnections in the far end. You get all the in- and output in the nearest end of the tube package. Slanting the two different tube branches can also support water circulation. And here is the place for brazing if you use copper tubes, brazing stainless steel is inviting trouble... -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Ken Dunn Sent: den 27 september 2005 18:05 To: Biofuel@sustainablelists.org Subject: Re: [Biofuel] Double wall heat exchange - Solar Hot Water Heater Mike, the bending is not the problem so much as bending a tube inside a tube without the inner tube flattening out or kinking. Though, the more I think about it, the inner tube, being smaller than the outter tube will be less likely to kink than the outter purely by smaller diameter and tighter bend radius. Moreover, I talked to a fellow this weekend that told me to try tightly wrapping the center tube with a heavy gauge, uninsulated wire then insert it into the outter tube, this will make up some difference in size and help to prevent kinking of the inner tube. I'm going to try this along with simply inserting the smaller tube inside the larger and bending. I had considered tube-in-tube-in-tube and running hot propolene glycol and water, in opposite directions, through it. I'm not sure that I'm still going to pursue that route except for experimentation purposes. Take care, Ken On 9/27/05, Mike Weaver [EMAIL PROTECTED] wrote: Maybe I'm losing my mind but I swear I used to have a kit w/ different head and a long bar that I used to bend copper pipe. I remember it as being very cheap (under 100.00 USD) at someplace like Norther Tool or Harbor Freight. Of cource I haven't done any plumbing in over 20 years - maybe the don't make it any more. -Mike Kjell Löfgren wrote: Ken, to avoid the tube bending business you can use a plate heat exchanger - more compact but if DIY you have to do some welding. Cut two equally sized pieces of *thin* stainless steel plate. Make about two dimples about 2 mm deep on every square 10 cm of the plate with a ball-peen(sp?) hammer (work on a wooden bench!). Weld the two plates together all around the edges with the sides with the raised dimples facing each other. Grind away the weld and cone out openings for the short pieces of pipes where the fluid goes in and out (on opposite corners). The short pipe pieces are welded in place. Carefully pressurize the unit with very low air pressure - less than 0.05 kg/cm2 - and test for leaks with soap water, remember to use clamps or something to hold the plates together or you end up with a pressurized 'football'! Make two or more of these units and submerge in whatever storage tank you use, you can connect them in series or in parallel as long as you avoid air pockets. The size of the plates is as big as needed but keep in mind that these DIY units are not meant to be used with internal pressure! Pressure can maybe be used inside the storage tank but the numbers of dimples have to be increased. Also beware of air pressure in large containers - even a small pressure can add up to large forces and even blow the container! Stainless steel rods for welding and a TIG welding equipment is also needed - a skilled TIG welding buddy will make things easier if you don't have the know-how. ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.o rg 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] Double wall heat exchange - Solar Hot Water Heater
Hey Ken; Liquids are almost uncompressable. Fill the tube with water and put a cap on each end with a compression fitting (swagelok etc) (underwater of course no bubbles allowed - you could probaly fill the tube and then tilt it up at one end and tape a bag around it with the tube poked through and fill the bag with water to put the remaining cap on) and then go ahead and bend your tubing. I have not tried this but have been told that it works. Filling with sand can be a problem in getting the sand out of the bend afterward. With a reducing union it should be able to be done with coaxial pipe as well. Hope it helps. Joe Mike Weaver wrote: Maybe I'm losing my mind but I swear I used to have a kit w/ different head and a long bar that I used to bend copper pipe. I remember it as being very cheap (under 100.00 USD) at someplace like Norther Tool or Harbor Freight. Of cource I haven't done any plumbing in over 20 years - maybe the don't make it any more. -Mike Kjell Lfgren wrote: Ken, to avoid the tube bending business you can use a plate heat exchanger - more compact but if DIY you have to do some welding. Cut two equally sized pieces of *thin* stainless steel plate. Make about two dimples about 2 mm deep on every square 10 cm of the plate with a ball-peen(sp?) hammer (work on a wooden bench!). Weld the two plates together all around the edges with the sides with the raised dimples facing each other. Grind away the weld and cone out openings for the short pieces of pipes where the fluid goes in and out (on opposite corners). The short pipe pieces are welded in place. Carefully pressurize the unit with very low air pressure - less than 0.05 kg/cm2 - and test for leaks with soap water, remember to use clamps or something to hold the plates together or you end up with a pressurized 'football'! Make two or more of these units and submerge in whatever storage tank you use, you can connect them in series or in parallel as long as you avoid air pockets. The size of the plates is as big as needed but keep in mind that these DIY units are not meant to be used with internal pressure! Pressure can maybe be used inside the storage tank but the numbers of dimples have to be increased. Also beware of air pressure in large containers - even a small pressure can add up to large forces and even blow the container! Stainless steel rods for welding and a TIG welding equipment is also needed - a skilled TIG welding buddy will make things easier if you don't have the know-how. -Original Message- *From:* [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]*On Behalf Of *Ken Dunn *Sent:* den 24 september 2005 08:02 *To:* Biofuel@sustainablelists.org *Subject:* [Biofuel] Double wall heat exchange - Solar Hot Water Heater Hi all, Sorry for the long subject line but, I thought it may aid in archive searches... Is there a home remedy to creating a double wall heat exchange? I have contemplated buying two sizes of copper tubing, inserting the smaller inside the larger and bending the two simultaneously. I could see how the inner tubing might kink or flatten out but, I think that would be unlikely unless I tried to bend too tight of a radius. Is there a better home-builder solution? Perhaps there is an affordable storage tank commercially available that makes building a backyard heat exchange mute anyway.? I'm going to need to come up with a storage tank anyway. I understand the theoretical pros/cons to internal and external heat exchanges but, what are the real-world practical differences? Thanks a bunch, Take care, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
On 9/27/05, Mike Weaver [EMAIL PROTECTED] wrote: Hmm...what if you centered the smaller tube and held it in place with spacers, wax would work, and then filled it with fine grain sand, then bent it? I'm sure it would, I think someone had already mentioned a similar technique. I think I'd like to stear clear of the sand in case of a major failure. Wax or not, I don't want to be flushing my entire system to get rid of unwanted sand. Keep the ideas coming, Take care, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
If the goal is to keep it simple, do two things differently than you are contemplating: 1 - make your heat exchanger by putting multiple loops of coiled copper in a polypropylene tank - at most you will need soldering skill if you want to break up a 3/4 or 1" flow into multiple 1/2" coils (surface area = good). One logical loop for (may be many loops of a smaller pipe diameter) for the load (ie DHW or hydronic heat) and (2 below) 2 - use a "drain down" open system instead of glycol. This allows you to use water everywhere. A pump (not a circulator) pumps the water up to your rooftop collectors when the system senses available heat (standard, cheap solar differential controls) and gravity drains it down when the system is not in use [this method requires that the panels be above the storage tank and that the pipes exposed to freezing are graded towards the storage tank - usually very easy to do] Note that the PP tank in step one above is the drain down tank and storage tank for your hot water (they can be separated if desired, and a larger tank/multiple tanks will provide additional storage, which is the key to effective solar hydronic installations). So you end up with one (open system)tank full of hot water from the sun, heating your coils of copper, containing the water from your (closed system)DHW. Similar technique (add a logical coil) for the hyrdonic side. Just make sure you don't always "preheat" your hydronic -sometimes the return water from your heating system will be hotter than your solar storage - you need a control to tell you whether there is heat available for the hyrdonic system (not an issue for preheating DHW - your solar storage temp will be almost always be above your groundwater temp). Tom From: Ken Dunn [EMAIL PROTECTED]Subject: Re: [Biofuel] Double wall heat exchange - Solar Hot Water HeaterDate: Tue, 27 Sep 2005 09:53:41 -0400To: Biofuel@sustainablelists.orgKjell,I will certainly give this a try for my own purposes, it seems simpleenough. But, I can operate a TIG and have access to one. Unfortunately, a TIG welder and the associated experience are notwidely spread. I do want to keep this project as Appropriate aspossible. So, I'm trying to find materials that are as readilyavailable as possible. Also, I plan to use propolene glycol so, thereis the issue of double walls. I could certainly adapt this ideaaccordingly. Its really too bad that brazing the plate togetherwouldn't be sufficient - that would make it an easier DIY.Thanks a bunch,Take care,KenOn 9/27/05, Kjell Löfgren <[EMAIL PROTECTED]>wrote: Ken, to avoid the tube bending business you can use a plate heat exchanger - more compact but if DIY you have to do some welding. Cut two equally sized pieces of *thin* stainless steel plate. Make about two dimples about 2 mmSNIPRadiance 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/
Re: [Biofuel] Double wall heat exchange - Solar Hot Water Heater
On 9/27/05, Kjell Löfgren [EMAIL PROTECTED] wrote: Ken, why not use straight tubes (if you have the space), one tube length (20 feet?) in one direction and the next tube length running back? You could put your three (four?) tubes into each other both ways and have a U-bend and some interconnections in the far end. You get all the in- and output in the nearest end of the tube package. This seems like a pretty good idea. 20 feet is much more space than I have to offer but, I could probably figure out a way to contain a tube-in-tube design inside a large diameter pvc pipe (6 ft long or so) capped at both ends and plumbed to create a homemade shell and tube heat exchanger. I'll have to look at the economics of this design. ___ 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] Double wall heat exchange - Solar Hot Water Heater
2 - use a drain down open system instead of glycol. This allows you to use water everywhere. A pump (not a circulator) pumps the water up to your rooftop collectors when the system senses available heat (standard, cheap solar differential controls) and gravity drains it down when the system is not in use [this method requires that the panels be above the storage tank and that the pipes exposed to freezing are graded towards the storage tank - usually very easy to do] Note that the PP tank in step one above is the drain down tank and storage tank for your hot water (they can be separated if desired, and a larger tank/multiple tanks will provide additional storage, which is the key to effective solar hydronic installations). If you are willing to use a pump instead of a circulator (much higher power draw is the problem, if you are off grid), and take some care in sloping pipes and collectors properly, it is a bit simpler. In addition, you avoid the issue of acidification of glycol, common in large closed loop systems that chronically stagnate in the summertime. ___ 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] Double wall heat exchange - Solar Hot Water Heater
Tom, Does a drain down system simplify anything other than the heat exchanger and eliminate the use of glycol? Or course, you're adding the drain down. It almost seems like a wash (there is a pun in there somewhere, I'm sure). I would like to use my solar hot water for space heating as well - either radiant heat or with a liquid to air heat exchanger and blower. Either way, I think I'd prefer a closed loop so that I'm not pumping DHW through excessive piping. Am I missing something else? If the goal is to keep it simple, do two things differently than you are contemplating: 1 - make your heat exchanger by putting multiple loops of coiled copper in a polypropylene tank - at most you will need soldering skill if you want to break up a 3/4 or 1 flow into multiple 1/2 coils (surface area = good). One logical loop for (may be many loops of a smaller pipe diameter) for the load (ie DHW or hydronic heat) and (2 below) 2 - use a drain down open system instead of glycol. This allows you to use water everywhere. A pump (not a circulator) pumps the water up to your rooftop collectors when the system senses available heat (standard, cheap solar differential controls) and gravity drains it down when the system is not in use [this method requires that the panels be above the storage tank and that the pipes exposed to freezing are graded towards the storage tank - usually very easy to do] Note that the PP tank in step one above is the drain down tank and storage tank for your hot water (they can be separated if desired, and a larger tank/multiple tanks will provide additional storage, which is the key to effective solar hydronic installations). So you end up with one (open system) tank full of hot water from the sun, heating your coils of copper, containing the water from your (closed system) DHW. Similar technique (add a logical coil) for the hyrdonic side. Just make sure you don't always preheat your hydronic -sometimes the return water from your heating system will be hotter than your solar storage - you need a control to tell you whether there is heat available for the hyrdonic system (not an issue for preheating DHW - your solar storage temp will be almost always be above your groundwater temp). Tom From: Ken Dunn [EMAIL PROTECTED] Subject: Re: [Biofuel] Double wall heat exchange - Solar Hot Water Heater Date: Tue, 27 Sep 2005 09:53:41 -0400 To: Biofuel@sustainablelists.org Kjell, I will certainly give this a try for my own purposes, it seems simple enough. But, I can operate a TIG and have access to one. Unfortunately, a TIG welder and the associated experience are not widely spread. I do want to keep this project as Appropriate as possible. So, I'm trying to find materials that are as readily available as possible. Also, I plan to use propolene glycol so, there is the issue of double walls. I could certainly adapt this idea accordingly. Its really too bad that brazing the plate together wouldn't be sufficient - that would make it an easier DIY. Thanks a bunch, Take care, Ken On 9/27/05, Kjell Löfgren wrote: Ken, to avoid the tube bending business you can use a plate heat exchanger - more compact but if DIY you have to do some welding. Cut two equally sized pieces of *thin* stainless steel plate. Make about two dimples about 2 mm SNIP 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] Double wall heat exchange - Solar Hot Water Heater
Ken, If you can use PVC pipe, your efficiency is very low to start with. Normal PVC starts to soften at 60 degree C and carbon reinforced ones at 95 degree C. The surface temperatures in normal copper based solar panels can be a few hundreds of degree C and it is always special soldering in them, otherwise the soldering will melt or degenerate. I would not recommend any plastics, if you cannot get the special ones that NASA uses. They are quite expensive, so do not forget to ask for a special discount, based on your good looks or intentions. Hakan At 20:04 27/09/2005, you wrote: On 9/27/05, Kjell Löfgren [EMAIL PROTECTED] wrote: Ken, why not use straight tubes (if you have the space), one tube length (20 feet?) in one direction and the next tube length running back? You could put your three (four?) tubes into each other both ways and have a U-bend and some interconnections in the far end. You get all the in- and output in the nearest end of the tube package. This seems like a pretty good idea. 20 feet is much more space than I have to offer but, I could probably figure out a way to contain a tube-in-tube design inside a large diameter pvc pipe (6 ft long or so) capped at both ends and plumbed to create a homemade shell and tube heat exchanger. I'll have to look at the economics of this design. ___ 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] Double wall heat exchange - Solar Hot Water Heater
On 9/27/05, Zeke Yewdall [EMAIL PROTECTED] wrote: If you are willing to use a pump instead of a circulator (much higher power draw is the problem, if you are off grid), and take some care in sloping pipes and collectors properly, it is a bit simpler. In addition, you avoid the issue of acidification of glycol, common in large closed loop systems that chronically stagnate in the summertime. Is there a way to balance the PH of the glycol to extend the life of it? I knew that there is maintenance. I assumed I would have to periodically flush and replace. ___ 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] Double wall heat exchange - Solar Hot Water Heater
Recently (this spring I believe) Home Power Magazine had a series of articles with nice diagrams of all the various solar hot water systems, space heating and DHW, batch heating, closed loop, and open loop systems. I'd recommend searching their archives, as these were the easiest to understand explanations that I'd seen in a while. Zeke On 9/27/05, Ken Dunn [EMAIL PROTECTED] wrote: Tom, Does a drain down system simplify anything other than the heat exchanger and eliminate the use of glycol? Or course, you're adding the drain down. It almost seems like a wash (there is a pun in there somewhere, I'm sure). I would like to use my solar hot water for space heating as well - either radiant heat or with a liquid to air heat exchanger and blower. Either way, I think I'd prefer a closed loop so that I'm not pumping DHW through excessive piping. Am I missing something else? If the goal is to keep it simple, do two things differently than you are contemplating: 1 - make your heat exchanger by putting multiple loops of coiled copper in a polypropylene tank - at most you will need soldering skill if you want to break up a 3/4 or 1 flow into multiple 1/2 coils (surface area = good). One logical loop for (may be many loops of a smaller pipe diameter) for the load (ie DHW or hydronic heat) and (2 below) 2 - use a drain down open system instead of glycol. This allows you to use water everywhere. A pump (not a circulator) pumps the water up to your rooftop collectors when the system senses available heat (standard, cheap solar differential controls) and gravity drains it down when the system is not in use [this method requires that the panels be above the storage tank and that the pipes exposed to freezing are graded towards the storage tank - usually very easy to do] Note that the PP tank in step one above is the drain down tank and storage tank for your hot water (they can be separated if desired, and a larger tank/multiple tanks will provide additional storage, which is the key to effective solar hydronic installations). So you end up with one (open system) tank full of hot water from the sun, heating your coils of copper, containing the water from your (closed system) DHW. Similar technique (add a logical coil) for the hyrdonic side. Just make sure you don't always preheat your hydronic -sometimes the return water from your heating system will be hotter than your solar storage - you need a control to tell you whether there is heat available for the hyrdonic system (not an issue for preheating DHW - your solar storage temp will be almost always be above your groundwater temp). Tom From: Ken Dunn [EMAIL PROTECTED] Subject: Re: [Biofuel] Double wall heat exchange - Solar Hot Water Heater Date: Tue, 27 Sep 2005 09:53:41 -0400 To: Biofuel@sustainablelists.org Kjell, I will certainly give this a try for my own purposes, it seems simple enough. But, I can operate a TIG and have access to one. Unfortunately, a TIG welder and the associated experience are not widely spread. I do want to keep this project as Appropriate as possible. So, I'm trying to find materials that are as readily available as possible. Also, I plan to use propolene glycol so, there is the issue of double walls. I could certainly adapt this idea accordingly. Its really too bad that brazing the plate together wouldn't be sufficient - that would make it an easier DIY. Thanks a bunch, Take care, Ken On 9/27/05, Kjell Löfgren wrote: Ken, to avoid the tube bending business you can use a plate heat exchanger - more compact but if DIY you have to do some welding. Cut two equally sized pieces of *thin* stainless steel plate. Make about two dimples about 2 mm SNIP 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
Re: [Biofuel] Double wall heat exchange - Solar Hot Water Heater
On 9/27/05, Hakan Falk [EMAIL PROTECTED] wrote: Ken, If you can use PVC pipe, your efficiency is very low to start with. Normal PVC starts to soften at 60 degree C and carbon reinforced ones at 95 degree C. The surface temperatures in normal copper based solar panels can be a few hundreds of degree C and it is always special soldering in them, otherwise the soldering will melt or degenerate. I would not recommend any plastics, if you cannot get the special ones that NASA uses. Thanks for his piece of information, I was not of heat sensivity of PVC. I thought that it was much more heat resistent. They are quite expensive, so do not forget to ask for a special discount, based on your good looks or intentions. Has my mom been bragging about me again? Thanks again, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
On 9/27/05, Zeke Yewdall [EMAIL PROTECTED] wrote: Recently (this spring I believe) Home Power Magazine had a series of articles with nice diagrams of all the various solar hot water systems, space heating and DHW, batch heating, closed loop, and open loop systems. I'd recommend searching their archives, as these were the easiest to understand explanations that I'd seen in a while. Yikes, Zeke, I can't look at another diagram until I get some work done. I have been reading endlessly, I think I might have seen every article in Home Power, Mother Earth News, SRCC, FSEC, EERE, DOE, Billy Boy Joe Bob's Ever-Expanding-Beer-Bottle system and more. Somethin's gotta get built. ___ 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] Double wall heat exchange - Solar Hot Water Heater
Is there a way to balance the PH of the glycol to extend the life of it? I knew that there is maintenance. I assumed I would have to periodically flush and replace. Hmmm. I'm not actually sure :) I know that it is recommended to test it every two years, but no one actually said what to do if it had gone bad... replace it I guess? ___ 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] Double wall heat exchange - Solar Hot Water Heater
You can actually buy C-PVC pipe for hot water piping here. Since the heat exchanger is not going to be operating at over 90C or so, it should work fine, except that it may be very difficult to get 100mm diamter CPVC. Normally anything that large is drain pipe not hot water supply, and will be normal PVC instead.As I understood your idea, you were going to put a few runs of copper pipe back and forth submerged inside the large PVC pipe, right? Zeke On 9/27/05, Hakan Falk [EMAIL PROTECTED] wrote: Ken, If you can use PVC pipe, your efficiency is very low to start with. Normal PVC starts to soften at 60 degree C and carbon reinforced ones at 95 degree C. The surface temperatures in normal copper based solar panels can be a few hundreds of degree C and it is always special soldering in them, otherwise the soldering will melt or degenerate. I would not recommend any plastics, if you cannot get the special ones that NASA uses. They are quite expensive, so do not forget to ask for a special discount, based on your good looks or intentions. Hakan At 20:04 27/09/2005, you wrote: On 9/27/05, Kjell Löfgren [EMAIL PROTECTED] wrote: Ken, why not use straight tubes (if you have the space), one tube length (20 feet?) in one direction and the next tube length running back? You could put your three (four?) tubes into each other both ways and have a U-bend and some interconnections in the far end. You get all the in- and output in the nearest end of the tube package. This seems like a pretty good idea. 20 feet is much more space than I have to offer but, I could probably figure out a way to contain a tube-in-tube design inside a large diameter pvc pipe (6 ft long or so) capped at both ends and plumbed to create a homemade shell and tube heat exchanger. I'll have to look at the economics of this design. ___ 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] Double wall heat exchange - Solar Hot Water Heater
On 9/27/05, Zeke Yewdall [EMAIL PROTECTED] wrote: You can actually buy C-PVC pipe for hot water piping here. Since the heat exchanger is not going to be operating at over 90C or so, it should work fine, except that it may be very difficult to get 100mm diamter CPVC. Normally anything that large is drain pipe not hot water supply, and will be normal PVC instead.As I understood your idea, you were going to put a few runs of copper pipe back and forth submerged inside the large PVC pipe, right? Yes, that's one of the ideas that I would like to test. ___ 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] Double wall heat exchange - Solar Hot Water Heater
Zeke Yewdall wrote: You can actually buy C-PVC pipe for hot water piping here. Since the heat exchanger is not going to be operating at over 90C or so, it should work fine, except that it may be very difficult to get 100mm diamter CPVC. Normally anything that large is drain pipe not hot water supply, and will be normal PVC instead.As I understood your idea, you were going to put a few runs of copper pipe back and forth submerged inside the large PVC pipe, right? Isn't the gray plastic electrical conduit C-PVC? Check with your local electrical shop rather than your home depot. --- David ___ 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] Double wall heat exchange - Solar Hot Water Heater
Zeke, I would not use PVC or C-PVC at all, if I wanted a long term solution with a life span of more than a couple plus years. I used some spare C-PVC in a watering system, with some small parts open to the air and partially the sun. After 3-4 years they had hardened and started to crack. This despite the very low pressure in the watering system, comparable with an open solar system. It is the surface to the sun that is critical, so running C-PVC inside a a large copper tube could work, but why would we like to do that? Plastic is a very bad heat exchanger anyway, compared o copper. C-PVC is usable up to 95 to 99 degree, depending on type and quality. Hakan At 20:45 27/09/2005, you wrote: You can actually buy C-PVC pipe for hot water piping here. Since the heat exchanger is not going to be operating at over 90C or so, it should work fine, except that it may be very difficult to get 100mm diamter CPVC. Normally anything that large is drain pipe not hot water supply, and will be normal PVC instead.As I understood your idea, you were going to put a few runs of copper pipe back and forth submerged inside the large PVC pipe, right? Zeke On 9/27/05, Hakan Falk [EMAIL PROTECTED] wrote: Ken, If you can use PVC pipe, your efficiency is very low to start with. Normal PVC starts to soften at 60 degree C and carbon reinforced ones at 95 degree C. The surface temperatures in normal copper based solar panels can be a few hundreds of degree C and it is always special soldering in them, otherwise the soldering will melt or degenerate. I would not recommend any plastics, if you cannot get the special ones that NASA uses. They are quite expensive, so do not forget to ask for a special discount, based on your good looks or intentions. Hakan At 20:04 27/09/2005, you wrote: On 9/27/05, Kjell Löfgren [EMAIL PROTECTED] wrote: Ken, why not use straight tubes (if you have the space), one tube length (20 feet?) in one direction and the next tube length running back? You could put your three (four?) tubes into each other both ways and have a U-bend and some interconnections in the far end. You get all the in- and output in the nearest end of the tube package. This seems like a pretty good idea. 20 feet is much more space than I have to offer but, I could probably figure out a way to contain a tube-in-tube design inside a large diameter pvc pipe (6 ft long or so) capped at both ends and plumbed to create a homemade shell and tube heat exchanger. I'll have to look at the economics of this design. ___ 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] Double wall heat exchange - Solar Hot Water Heater
On 9/27/05, Hakan Falk [EMAIL PROTECTED] wrote: It is the surface to the sun that is critical, so running C-PVC inside a a large copper tube could work, but why would we like to do that? Plastic is a very bad heat exchanger anyway, compared o copper. C-PVC is usable up to 95 to 99 degree, depending on type and quality. Hakan, The CPVC would only be used to house the heat exchanger which would be in the basement. All piping to, from and within the collector would still be copper. Besides, I'm still very much in the experimental stage. Thanks for you comments, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
On 9/27/05, David Miller [EMAIL PROTECTED] wrote: Isn't the gray plastic electrical conduit C-PVC? Check with your local electrical shop rather than your home depot. Is that safe for carrying drinking though? If so, that's a good lead. I could always run my potable water through the heat exchanger and glycol through the PVC but, I definitely need to know what's healthy and what's not. ___ 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] Double wall heat exchange - Solar Hot Water Heater
Well, in this case, there is not supposed to be any heat transfer through the PVC, so I wouldn't be worried about that. I agree that metal would be better, it you can find some large diameter metal pipe for cheap. What about just putting a coil of copper tubing in a big metal trash can? Certainly not elegant, but it would be cheap, and require just about no manufacturing. On the sunlight issue, the problem is that UV turns the surface of PVC (and apparently CPVC) into a different chemical compound that is much harder than PVC, but much more brittle. It serves as a crack initiator, and causes the entire thickness of PVC to crack easily, even though only the very surface has actually been affected by the sunlight. If you sand the discoloured surface off, it regains it's original plasticity because you have removed the crack initiator layer. This is from the Unibell PVC manufacturers association, that I attended a workshop from. On 9/27/05, Hakan Falk [EMAIL PROTECTED] wrote: Zeke, I would not use PVC or C-PVC at all, if I wanted a long term solution with a life span of more than a couple plus years. I used some spare C-PVC in a watering system, with some small parts open to the air and partially the sun. After 3-4 years they had hardened and started to crack. This despite the very low pressure in the watering system, comparable with an open solar system. It is the surface to the sun that is critical, so running C-PVC inside a a large copper tube could work, but why would we like to do that? Plastic is a very bad heat exchanger anyway, compared o copper. C-PVC is usable up to 95 to 99 degree, depending on type and quality. Hakan At 20:45 27/09/2005, you wrote: You can actually buy C-PVC pipe for hot water piping here. Since the heat exchanger is not going to be operating at over 90C or so, it should work fine, except that it may be very difficult to get 100mm diamter CPVC. Normally anything that large is drain pipe not hot water supply, and will be normal PVC instead.As I understood your idea, you were going to put a few runs of copper pipe back and forth submerged inside the large PVC pipe, right? Zeke On 9/27/05, Hakan Falk [EMAIL PROTECTED] wrote: Ken, If you can use PVC pipe, your efficiency is very low to start with. Normal PVC starts to soften at 60 degree C and carbon reinforced ones at 95 degree C. The surface temperatures in normal copper based solar panels can be a few hundreds of degree C and it is always special soldering in them, otherwise the soldering will melt or degenerate. I would not recommend any plastics, if you cannot get the special ones that NASA uses. They are quite expensive, so do not forget to ask for a special discount, based on your good looks or intentions. Hakan At 20:04 27/09/2005, you wrote: On 9/27/05, Kjell Löfgren [EMAIL PROTECTED] wrote: Ken, why not use straight tubes (if you have the space), one tube length (20 feet?) in one direction and the next tube length running back? You could put your three (four?) tubes into each other both ways and have a U-bend and some interconnections in the far end. You get all the in- and output in the nearest end of the tube package. This seems like a pretty good idea. 20 feet is much more space than I have to offer but, I could probably figure out a way to contain a tube-in-tube design inside a large diameter pvc pipe (6 ft long or so) capped at both ends and plumbed to create a homemade shell and tube heat exchanger. I'll have to look at the economics of this design. ___ 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] Double wall heat exchange - Solar Hot Water Heater
David, I doubt it, since the plastic pipes are colored according to a system and gray is normal PVC. I have also seen those gray tubing exposed to the sun and the get discolored after a while, with fine cracks on the surface. Since this electrical tubing is an electrical insolation, it is no demands on holding of liquids. Most C-PVC I seen are for heated floor and they are transparent/yellow, if you ask me that have a slightly defect color seeing, as most men. If you want a more exact color, always ask a women. Hakan At 21:04 27/09/2005, you wrote: Zeke Yewdall wrote: You can actually buy C-PVC pipe for hot water piping here. Since the heat exchanger is not going to be operating at over 90C or so, it should work fine, except that it may be very difficult to get 100mm diamter CPVC. Normally anything that large is drain pipe not hot water supply, and will be normal PVC instead.As I understood your idea, you were going to put a few runs of copper pipe back and forth submerged inside the large PVC pipe, right? Isn't the gray plastic electrical conduit C-PVC? Check with your local electrical shop rather than your home depot. --- David ___ 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] Double wall heat exchange - Solar Hot Water Heater
I agree, the gray stuff is just normal PVC, except that I think it has flame retardant added for electrical conduit. Darker colors will also hold up to the sun somewhat better, but obviously not perfectly. On 9/27/05, Hakan Falk [EMAIL PROTECTED] wrote: David, I doubt it, since the plastic pipes are colored according to a system and gray is normal PVC. I have also seen those gray tubing exposed to the sun and the get discolored after a while, with fine cracks on the surface. Since this electrical tubing is an electrical insolation, it is no demands on holding of liquids. Most C-PVC I seen are for heated floor and they are transparent/yellow, if you ask me that have a slightly defect color seeing, as most men. If you want a more exact color, always ask a women. Hakan At 21:04 27/09/2005, you wrote: Zeke Yewdall wrote: You can actually buy C-PVC pipe for hot water piping here. Since the heat exchanger is not going to be operating at over 90C or so, it should work fine, except that it may be very difficult to get 100mm diamter CPVC. Normally anything that large is drain pipe not hot water supply, and will be normal PVC instead.As I understood your idea, you were going to put a few runs of copper pipe back and forth submerged inside the large PVC pipe, right? Isn't the gray plastic electrical conduit C-PVC? Check with your local electrical shop rather than your home depot. --- David ___ 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] Double wall heat exchange - Solar Hot Water Heater
On 9/27/05, Zeke Yewdall [EMAIL PROTECTED] wrote: Well, in this case, there is not supposed to be any heat transfer through the PVC, so I wouldn't be worried about that. I agree that metal would be better, it you can find some large diameter metal pipe for cheap. What about just putting a coil of copper tubing in a big metal trash can? Certainly not elegant, but it would be cheap, and require just about no manufacturing. Well, while I couldn't care much less about the elegance of the installation, my kids are still young and I'd like to find someone to buy my house when I'm ready to move into a smaller space. Also, as I've mentioned several times, I would like to help others with solutions like solar hot water. And frankly, I live in the U.S. where things are supposed to be both sexy and puritanical simultaneously. A big metal trash can is neither. Furthermore, I would like to continue living in the house with my wife once its all said and done. I'm pretty sure that my wife would be just a bit leary of our drinking water getting anywhere near a trash can. Thanks, ___ 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] Double wall heat exchange - Solar Hot Water Heater
Ken, If it is a pure heat exchanger, you need more than double the surface for plastic, than for metal. This apart from the possible defects that can develop in plastics. If it is only the housing of 2 heat exchange loops, why not use a steel drum, with copper tubing for the two loops. The cost should be close to the same, if you consider the material efficiency and corresponding amounts. Hakan At 21:27 27/09/2005, you wrote: On 9/27/05, Hakan Falk [EMAIL PROTECTED] wrote: It is the surface to the sun that is critical, so running C-PVC inside a a large copper tube could work, but why would we like to do that? Plastic is a very bad heat exchanger anyway, compared o copper. C-PVC is usable up to 95 to 99 degree, depending on type and quality. Hakan, The CPVC would only be used to house the heat exchanger which would be in the basement. All piping to, from and within the collector would still be copper. Besides, I'm still very much in the experimental stage. Thanks for you comments, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
PS, Do not forget to insulate the steel drum well and maybe enhance the looks that way. Hakan At 22:03 27/09/2005, you wrote: Ken, If it is a pure heat exchanger, you need more than double the surface for plastic, than for metal. This apart from the possible defects that can develop in plastics. If it is only the housing of 2 heat exchange loops, why not use a steel drum, with copper tubing for the two loops. The cost should be close to the same, if you consider the material efficiency and corresponding amounts. Hakan At 21:27 27/09/2005, you wrote: On 9/27/05, Hakan Falk [EMAIL PROTECTED] wrote: It is the surface to the sun that is critical, so running C-PVC inside a a large copper tube could work, but why would we like to do that? Plastic is a very bad heat exchanger anyway, compared o copper. C-PVC is usable up to 95 to 99 degree, depending on type and quality. Hakan, The CPVC would only be used to house the heat exchanger which would be in the basement. All piping to, from and within the collector would still be copper. Besides, I'm still very much in the experimental stage. Thanks for you comments, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
On 9/27/05, Hakan Falk [EMAIL PROTECTED] wrote: If it is only the housing of 2 heat exchange loops, This is the purpose. I won't be using any plastic-like material to exchange heat. Sorry, if I didn't make that completely evident. why not use a steel drum, with copper tubing for the two loops. The cost should be close to the same, if you consider the material efficiency and corresponding amounts. I may end up using a steel drum. I'm try to find the best option to match whatever materials that I can find locally. For what it's worth, there is an issue of space efficiency also. The steel drum might not meet those requirements. Having the greatest number of options at my disposal can only benefit me and anyone that might want to the do same for themselves. Take care, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
Ken, do not use PVC for drinking water, the softener DEHP in the PVC material is slowly leaking out and there is also other nonhealthy stuff (chlorine!) in PVC. Personally I would put my ? (or whatever) on stainless steel, 18/8 sounds nice to me, almost beautiful... -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Ken Dunn Sent: den 27 september 2005 21:54 To: Biofuel@sustainablelists.org Subject: Re: [Biofuel] Double wall heat exchange - Solar Hot Water Heater On 9/27/05, Zeke Yewdall [EMAIL PROTECTED] wrote: Well, in this case, there is not supposed to be any heat transfer through the PVC, so I wouldn't be worried about that. I agree that metal would be better, it you can find some large diameter metal pipe for cheap. What about just putting a coil of copper tubing in a big metal trash can? Certainly not elegant, but it would be cheap, and require just about no manufacturing. Well, while I couldn't care much less about the elegance of the installation, my kids are still young and I'd like to find someone to buy my house when I'm ready to move into a smaller space. Also, as I've mentioned several times, I would like to help others with solutions like solar hot water. And frankly, I live in the U.S. where things are supposed to be both sexy and puritanical simultaneously. A big metal trash can is neither. Furthermore, I would like to continue living in the house with my wife once its all said and done. I'm pretty sure that my wife would be just a bit leary of our drinking water getting anywhere near a trash can. Thanks, ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.o rg 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] Double wall heat exchange - Solar Hot Water Heater
Thanks, everyone, for the advice. I went to the PA Energy Fest yesterday and talked to experienced folks there as well. I got some ideas how to incorporate some the concepts mentioned in this thread and also some others. I'm going to experiment on a smaller scale and design my heat exchange accordingly. Thanks again for the input, Take care, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
Very nice. Please share your results during your progress. Cheers On 9/25/2005, Ken Dunn [EMAIL PROTECTED] wrote: Thanks, everyone, for the advice. I went to the PA Energy Fest yesterday and talked to experienced folks there as well. I got some ideas how to incorporate some the concepts mentioned in this thread and also some others.. I'm going to experiment on a smaller scale and design my heat exchange accordingly. Thanks again for the input, Take care, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
Hi all, Sorry for the long subject line but, I thought it may aid in archive searches... Is there a home remedy to creating a double wall heat exchange? I have contemplated buying two sizes of copper tubing, inserting the smaller inside the larger and bending the two simultaneously. I could see how the inner tubing might kink or flatten out but, I think that would be unlikely unless I tried to bend too tight of a radius. Is there a better home-builder solution? Perhaps there is an affordable storage tank commercially available that makes building a backyard heat exchange mute anyway.? I'm going to need to come up with a storage tank anyway. I understand the theoretical pros/cons to internal and external heat exchanges but, what are the real-world practical differences? Thanks a bunch, Take care, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
I know Rheem makes (or made) a domestic HW tank that had an internal heat exchange coil. Presumably made for solar heat. I was examining it a while back. However, being in Canada the Canadian branch did not carry it. I have seen others build their own exchangers using solid copper pipe, utilizing reducers to actually position smaller diameter pipe inside the larger diameter pipe. The reducers were installed backwards such that the small end pointed into the larger pipe. I may have the picture files (assuming I saved them). If interested I'll try to locate them. John On 9/24/2005, Ken Dunn [EMAIL PROTECTED] wrote: Hi all, Sorry for the long subject line but, I thought it may aid in archive searches... Is there a home remedy to creating a double wall heat exchange? I have contemplated buying two sizes of copper tubing, inserting the smaller inside the larger and bending the two simultaneously. I could see how the inner tubing might kink or flatten out but, I think that would be unlikely unless I tried to bend too tight of a radius. Is there a better home-builder solution? Perhaps there is an affordable storage tank commercially available that makes building a backyard heat exchange mute anyway.? I'm going to need to come up with a storage tank anyway. I understand the theoretical pros/cons to internal and external heat exchanges but, what are the real-world practical differences? Thanks a bunch, Take care, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
Commerciall tanks tend to be pretty expensive. I have heard of people doing as John says with two diameters of pipe. I think there is also a company that makes just double wall heat exhangers that you can buy by the foot. I can't remember the name, but they usually have an ad in Home Power mazagine, which you can download from their website for free and look for the ad. www.homewpower.com On 9/24/05, John Mullan [EMAIL PROTECTED] wrote: I know Rheem makes (or made) a domestic HW tank that had an internal heat exchange coil. Presumably made for solar heat. I was examining it a while back. However, being in Canada the Canadian branch did not carry it. I have seen others build their own exchangers using solid copper pipe, utilizing reducers to actually position smaller diameter pipe inside the larger diameter pipe. The reducers were installed backwards such that the small end pointed into the larger pipe. I may have the picture files (assuming I saved them). If interested I'll try to locate them. John On 9/24/2005, Ken Dunn [EMAIL PROTECTED] wrote: Hi all, Sorry for the long subject line but, I thought it may aid in archive searches... Is there a home remedy to creating a double wall heat exchange? I have contemplated buying two sizes of copper tubing, inserting the smaller inside the larger and bending the two simultaneously. I could see how the inner tubing might kink or flatten out but, I think that would be unlikely unless I tried to bend too tight of a radius. Is there a better home-builder solution? Perhaps there is an affordable storage tank commercially available that makes building a backyard heat exchange mute anyway.? I'm going to need to come up with a storage tank anyway. I understand the theoretical pros/cons to internal and external heat exchanges but, what are the real-world practical differences? Thanks a bunch, Take care, Ken ___ 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] Double wall heat exchange - Solar Hot Water Heater
Ken wrote: Hi all, Sorry for the long subject line but, I thought it may aid in archive searches... Is there a home remedy to creating a double wall heat exchange? I have contemplated buying two sizes of copper tubing, inserting the smaller inside the larger and bending the two simultaneously. I could see how the inner tubing might kink or flatten out but, I think that would be unlikely unless I tried to bend too tight of a radius. Is there a better home-builder solution? Perhaps there is an affordable storage tank commercially available that makes building a backyard heat exchange mute anyway.? I'm going to need to come up with a storage tank anyway. I understand the theoretical pros/cons to internal and external heat exchanges but, what are the real-world practical differences? Disclaimer - I have not tried this myself. I have read (somewhere) that if you start with straight tubing, then pack sand between the two tubes before making your bends, this will avoid/ reduce kinking in the inner tube. Of course, the trick is probably getting all the sand out again before plumbing this new arrangement into the lines. If I end up going this route (double-wall) some day in the future, I think I will put two coils into an exchange tank instead. One coil provides the heat input from the solar collectors, the other coil provides the heat input to the conventional hot water tank. The tank will have a sealable lid, and a lot of insulation. Both coils will be immersed in water in the tank. This way, the lid can be removed for inspections, and the coils can be removed fairly easily for repairs. To date, my solar water pre-heaters are in-line, so no heat exhangers required. Darryl McMahon -- Darryl McMahon http://www.econogics.com/ It's your planet. If you won't look after it, who will? ___ 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] Double wall heat exchange - Solar Hot Water Heater
Mandrel benders are cheap most places and will do the same thing better... Darryl McMahon wrote: Ken wrote: Hi all, Sorry for the long subject line but, I thought it may aid in archive searches... Is there a home remedy to creating a double wall heat exchange? I have contemplated buying two sizes of copper tubing, inserting the smaller inside the larger and bending the two simultaneously. I could see how the inner tubing might kink or flatten out but, I think that would be unlikely unless I tried to bend too tight of a radius. Is there a better home-builder solution? Perhaps there is an affordable storage tank commercially available that makes building a backyard heat exchange mute anyway.? I'm going to need to come up with a storage tank anyway. I understand the theoretical pros/cons to internal and external heat exchanges but, what are the real-world practical differences? Disclaimer - I have not tried this myself. I have read (somewhere) that if you start with straight tubing, then pack sand between the two tubes before making your bends, this will avoid/ reduce kinking in the inner tube. Of course, the trick is probably getting all the sand out again before plumbing this new arrangement into the lines. If I end up going this route (double-wall) some day in the future, I think I will put two coils into an exchange tank instead. One coil provides the heat input from the solar collectors, the other coil provides the heat input to the conventional hot water tank. The tank will have a sealable lid, and a lot of insulation. Both coils will be immersed in water in the tank. This way, the lid can be removed for inspections, and the coils can be removed fairly easily for repairs. To date, my solar water pre-heaters are in-line, so no heat exhangers required. Darryl McMahon ___ 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/
