What I've got and what I want - help appreciated

[Mr Pipples]

Hi there. Am considering adding solar and wood burner (with back boiler for heating just hot water and pref' poss' to cook on) sources to gas heating system and am wondering on best way to go...

Currently have Buderus 600 condensing boiler as source for ch and hw. Also have a newish cylinder (162L indirect gravity fed) that is linked up as a seperate ch zone to the boiler via a thermostat on the tank. (This was left over from old oil-powered rayburn system that was in place up till a couple of years ago - thought I'd keep it and use it for filling the bath and ensuite shower - maybe not that economical an idea!)

Hopefully you can see from the attached pic where stuff is roughly. Thinking to move up and use the existing single coil cylinder as a solar pre-heater tank for a new twin coil cylinder - to be further heated if necessary by the boiler and possibly the wood burner if and when this might get used in the future.

Largish old family house with a south facing roof. Still need to buy wood burner/cooker, solar panel, twin coil cylinder, etc.

What do you reckon? Thoughts on design, required items, etc. much appreciated - can possibly supply additional info' if that would help.

Cheers.

[Loir]

I have a HW cylinder that is heated by solar panels. Then this feeds down to a conventional HW cylinder in the airing cupboard that is heated by the boiler. If I was starting from scratch I wouldn't do it this way.

My solar cylinder is heating nicely with the sun today, it will be above 60C by the end of the day. But the water in the cylinder in the airing cupboard is gradually cooling. It will only get hot water into it if some hot water (well, warm water) is drawn off. Then the new hot water will mix with the warm water that is already there. So I will have slightly warmer water. The only way to get lots of the solar heated water into the cylinder and out to the taps would be to use a good quantity. Like have a shower. 

Changing it around is too big a job but I will have a go at pumping from the top solar cylinder to the bottom some time.

You might want to consider how to move the solar heated water to your bottom cylinder, too.  Or to have a change-over valve to use the solar water if it is hotter than the other cylinder.

Loir

[Mr Pipples]

The only way to get lots of the solar heated water into the cylinder and out to the taps would be to use a good quantity. Like have a shower. 

Loir

Thanks for your response Loir.

That's what the main use of the cylinders will be - 2x showers and maybe a bath. That's where most hot water goes - may do something separate later for dishwasher and washing machine.

[dhaslam]

Does the existing cylinder position suit the woodburner?  If it does then it would  be  better just to replace the cylinder with a conventional solar cylinder with  extra coils for the stove and gas  and a central heating  coil for output.   The only proviso would be that the new cylinder needs to be large and well insulated. The the solar panels need to be a bit larger than normal   because in summer the larger cylinder would need and could handle more solar input.       

[sleepybubble]

erm... in your diagram you have the cylinder downstairs and the boiler upstairs, and you say your boiler gravity cycles to the cylinder....

How does that work then? surely they should be the other way around....

[Mr Pipples]

erm... in your diagram you have the cylinder downstairs and the boiler upstairs, and you say your boiler gravity cycles to the cylinder....

How does that work then? surely they should be the other way around....

The boiler doesn't gravity feed to the cylinder - it's pumped. The water to be heated for distribution (ie not what's in the ch system loop) fills by gravity from the water tank in the loft - it's not a mains pressure system, or combi delivered (just combi heated) and therefore would be called gravity fed - as far as I'm aware: http://www.gasapplianceguide.co.uk/central_heating_systems.htm

[Mr Pipples]

Does the existing cylinder position suit the woodburner?  If it does then it would  be  better just to replace the cylinder with a conventional solar cylinder with  extra coils for the stove and gas  and a central heating  coil for output.   The only proviso would be that the new cylinder needs to be large and well insulated. The the solar panels need to be a bit larger than normal   because in summer the larger cylinder would need and could handle more solar input.       

Do you mean just have one 3 coil cylinder? Yep, the existing cylinder is in the right place for easy link up to a wood burner but is on the ground floor and therefore quite far from where the solar panels will be sited on the roof. So, I was thinking that maybe a separate cylinder near to the solar panels might work better... You might be right though - can I get a 3 coil cylinder and would this layout work better considering the solar to cylinder factor?

[billi]

Here are woodburning central heating cooker

http://www.windhager.com/fileadmin/user_upload/ZHN_KSN_01.pdf


Billi

[dhaslam]

The extra  pipe run needed to drop an extra floor is very small.   If you have two cylinders you have this extra connection anyway.   Having everything in one cylinder allows you to get avoid overheating in the summer by running the central heating circulation pump and if you have large panels the heat can  assist heating in spring and autumn.   You need to have enough space above the central heating take off point for domestic water needs.   

[Mr Pipples]

The extra  pipe run needed to drop an extra floor is very small.   If you have two cylinders you have this extra connection anyway.   Having everything in one cylinder allows you to get avoid overheating in the summer by running the central heating circulation pump and if you have large panels the heat can  assist heating in spring and autumn.   You need to have enough space above the central heating take off point for domestic water needs.   

OK, see what you're saying. Could you possibly recommend actual kit required as after looking through what Navitron are selling it's not seeming obvious to me. Cheers.

[Mr Pipples]

Here are woodburning central heating cooker

http://www.windhager.com/fileadmin/user_upload/ZHN_KSN_01.pdf


Billi

Can't find a price for these online - can you give me an idea? Cheers.

[dhaslam]

Navitron only have up to 1.8m tall cylinders listed on their website and only have a price up to 500mm wide but they can supply 550s.   The prices of the various additions come up on the dialog box  but you cannot order online because the website only allows one option.    The standard cylinder has only the solar coil so you need two input coils.   The underfloor heating coil seems very expensive, I suppose you could use a third input coil instead.    If possible a taller cylinder would be better because it would allow more separation of the coils.  Remember that the solar input needs its own space, the two boilers need a good buffer zone in the middle and plenty of space on top  that won't be cooled too by the  heating circuit.    The best thing is to give them the details and  let them  suggest the  best options.    I have ordered two 30 tube 47mm panels which hopefully will  allow all other heating to be off for almost half of the year but they won't be installed for another few weeks so I am only working in theory.


http://www.navitron.org.uk/product_detail.php?proID=114&catID=88

[wookey]

See numerous threads here along similar lines. The most efficient way to do this is to have one tank (lower losses, heat always in right tank). If you go for a thermal store rather than a hot water tank, then the wood-burner (and preferably the boiler) can (should) be directly-conencted, not through coils. This way it is also easy to use the hot water for heating as well as DHW (should you wish to). Ideally such a tank would be stratified and top-loading, but good stratifiers currently only seem to be available in very expensive tanks.

Lightfoot will no doubt be along shortly to explain how big your tank should be to accomodate the wood-burner inputs. Or just read some of the many previous threads.

[Mr Pipples]

Thanks for all the advice - have sent a request for designs, prices, etc. to Navitron after considering your suggestions. Any recommendations on other suppliers to check with/up on also?

[martin]

hrrrumph!
"Any other suppliers?"............unlike the BBC, which does the "there are other suppliers" thing we don't have to...........
Although I spend a lot of time here, I run a totally independent company that is free to buy from whoever we want to - in the field of solar hot water, we have never found the need to purchase from other sources.........
To my mind, there are a few companies around who are cheaper (usually on Fleabay) who are best avoided - it's very hard to find out beforehand if their products are any good - often they're of extremely poor quality, and sometimes they'll offer downright illegal tanks.........
Newark tanks, which Navitron offer, are probably the highest quality tank available - they will make almost anything you want to special order, and considering the quality, are excellent value.....
I've been noticing in recent weeks a lot of people discussing "other" makes of tanks, on investigation they often turn out to be overpriced, and inferior to the "house" make
Last but not least, we've dealt with Navitron for some years, and have always found their after-sales service excellent - so you pays your money, and takes your choice!
If you're doing a "first", or "once and only" install, its probably wise to stick to established combinations of equipment -
other people have done the experimentation, made the mistakes, and you get the benefit of something that's been well-proven!