ll 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
(ch
-
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, the
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
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
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 s
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
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 plas
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 dema
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? Certainl
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 hea
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 degr
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 de
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
>wat
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 th
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 nor
>
> 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
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
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
imes 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 b
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
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,
ot; 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
> 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 sys
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 interc
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
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
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 ho
] 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
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
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 b
>
> -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
>
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 fi
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?)
ha
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
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 acco
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 contempla
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 simult
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 mazag
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,
utilizi
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
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