navitron
 
Renewable Energy and Sustainability Forum
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Anyone wishing to register as a new member on the forum is strongly recommended to use a "proper" email address. Following continuous spam/hack attempts on the forum, "disposable" email addresses like Gmail, Yahoo and Hotmail tend to be viewed with suspicion, and the application rejected if there is any doubt whatsoever
 
Recent Articles: Navitron Partners With Solax to Help Create A More Sustainable Future | Navitron Calls for Increased Carbon Footprint Reduction In Light of Earth Overshoot Day | A plea from The David School - Issue 18
   Home   Help Search Login Register  
Pages: [1] 2 3   Go Down
  Print  
Author Topic: Wood burner feeding cylinder on same floor with door in the way  (Read 21841 times)
Greenbeast
Hero Member
*****
Offline Offline

Posts: 2319


WWW
« on: October 16, 2012, 03:37:33 PM »

Gonna put a wood burner in my static caravan and though might be handy to heat the HWC with it but the main entrance to the 'van is in between the burner location and the cylinder location, meaning the pipework would have to go up and over the door.

I assume this is a no go for a thermosyphon.

Might have to think about changing the intended location of the burner 
Logged
dhaslam
Hero Member
*****
Offline Offline

Posts: 6775



« Reply #1 on: October 16, 2012, 03:45:24 PM »

Can the return pipe go underneath the door?
Logged

DHW 250 litre cylinder  60 X 47mm tubes
Heating  180,000 litre straw insulated seasonal store, 90X58mm tubes + 7 sqm flat collectors, 1 kW VAWT, 3 kW heatpump plus Walltherm gasifying stove
johnrae
Hero Member
*****
Offline Offline

Posts: 764


« Reply #2 on: October 16, 2012, 04:02:59 PM »

Feed pipe (hot side) over the door and return (cold side) under the door (floor).  With a 2 metre height differential you should get a good thermo-syphon effect, even with a drop from door height to cylinder entry point.
Logged
Greenbeast
Hero Member
*****
Offline Offline

Posts: 2319


WWW
« Reply #3 on: October 17, 2012, 08:20:57 AM »

much thanks chaps! that is most certainly doable!
Logged
Billy
Guest
« Reply #4 on: October 17, 2012, 01:00:05 PM »

Top feeding rads from roof height manifold used to be the norm in tall buildings before pumps, at least it was in the states.  It will work just fine.

Logged
johnrae
Hero Member
*****
Offline Offline

Posts: 764


« Reply #5 on: October 17, 2012, 01:15:10 PM »

One point  -  make sure your pipework is large enough  -  22mm minimum / 28mm preferred and "slow" bend rather than sharp right angles
Logged
Greenbeast
Hero Member
*****
Offline Offline

Posts: 2319


WWW
« Reply #6 on: October 17, 2012, 01:53:07 PM »

Yeah i thinking 22/28 with plenty of curves Cheesy
Logged
Greenbeast
Hero Member
*****
Offline Offline

Posts: 2319


WWW
« Reply #7 on: October 17, 2012, 03:29:14 PM »

I will not have a lot of head room for the overflow pipe and expansion tank, i imagine it's be a few inches above the horizontal pipe run

will that cause a problem?
Logged
rogeriko
Hero Member
*****
Offline Offline

Posts: 1445



WWW
« Reply #8 on: October 17, 2012, 03:58:51 PM »

Pressurize the whole system like everyone else in the world and you dont have to worry about an expansion tank. Use a regulator to keep it to 1 bar or so. stir stir
Logged

johnrae
Hero Member
*****
Offline Offline

Posts: 764


« Reply #9 on: October 17, 2012, 06:45:35 PM »

I agree with Roger but having spent 30+ years of using a header tank (15 metres or 0.5 bar of hydrostatic head) but now changing to a sealed system (due to a probable new boiler installation) who am I to comment.  I suppose there are arguments that pressurising (via a suitably sized expansion vessel with 0.5 bar precharge) to 1 bar may lead to old joints or radiators leaking but such defects need sorting out sooner rather later.  With a "new" build all joints should be built leak-free irrespective of working pressure.
Logged
Greenbeast
Hero Member
*****
Offline Offline

Posts: 2319


WWW
« Reply #10 on: October 17, 2012, 07:32:39 PM »

is pressurising a serious prospect for me? with a standard cylinder
Logged
Billy
Guest
« Reply #11 on: October 17, 2012, 08:35:57 PM »

I use a 3 bar pressure relief valve close to the top outlet of the stove/boiler, just in case.  Been fine for many years now but don't forget an expansion tank or the valve will dribble when the system pressurises.   There is a formula for what size to use in comparison to your system volume somewhere.  Mine is 20 litres but I have a high volume system.

Logged
johnrae
Hero Member
*****
Offline Offline

Posts: 764


« Reply #12 on: October 17, 2012, 09:08:50 PM »

Taking a step back

You suggest concern about your cylinder.  Do I read that your hot cylinder water is actually circulating through your boiler (copper or stainless steel).  If so then you do NOT operate a pressurised system.   How do you currently feed water into your cylinder (header tank?)  Perhaps a rough sketch of what you have will get you the correct answer, rather than some potentially dangerous solutions.

Unless your boiler is copper or stainless steel you MUST use an indirect coil in your cylinder, otherwise your hot water will be a lovely brown colour.

Should you want/need to put together a pressurised system, using an indirect coil in your cylinder, then volume of expansion vessel is nominally 10% of the system volume.  So evaluate the volume of cold water in boiler+piping+cylinder coil and minimum volume of expansion vessel required is 10% of this figure.  The expansion vessel has a rubber diaphragm installed to create a sealed air cushion for the expanding water to compress.  The air precharge pressure is usually 0.5bar (pumped in through a schrader valve.  The water circuit is then pressurised to 1 bar.  This will increase slightly, say to about 1.5bar (depends on how oversized your expansion vessel is) as the water heats up.  As Billy says you also need a pressure relief valve and this should be set to around 3bar.  At a guess, your system volume will be pretty low, say less than 20 litres so your expansion vessel will be extremely small (say a couple of litres or so)
Logged
Greenbeast
Hero Member
*****
Offline Offline

Posts: 2319


WWW
« Reply #13 on: October 17, 2012, 09:25:38 PM »

the cylinder is the only existing thing and it's not even inside the caravan yet Smiley
it is a standard indirect cylinder with one coil which i'm planning on running the wood burner through.

all other system design considerations can be created from scratch

my current concern is having only a few inches above the flow pipe to accommodate an overflow pipe.
if i can avoid that by running an expansion vessel and prv then great, i have plumbed a pressurised solar system before, is this essentially the same?
Logged
Greenbeast
Hero Member
*****
Offline Offline

Posts: 2319


WWW
« Reply #14 on: October 19, 2012, 09:57:10 AM »

Thoughts?
Logged
Pages: [1] 2 3   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2013, Simple Machines
SMFAds for Free Forums
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!