Integrated woodburner, solar tubes, oil combi and underground heatstore.

[noelsquibb]

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[desperate]

Noel

That's effin brilliant, I do believe your more nuts than me, have an applaud, and whats more if our paths ever cross the beers on me.

Desperate

[noelsquibb]

Thanx Desp I could use a beer..

and back to the main story -

Next job was to beef up the heat exchanger array enough to stand it up and transfer it from the shed floor to the pit.  
I wonderd If I should heat test the support legs, aka BT duct, cos incoming pressurised hot water could theoretically reach 110deg c and it would be a proper nuisance if the legs faild.
If I lower the heat exchanger array into a dry pit, I can watch it down but if I lower it into a pit nearly full of water, it will get lighter as it goes down and with some careful measurements will give me an indication of volume, complicated only by a deduction for the volume of copper tube, pressed steel and plastic legs. I sort of need to know the volume of water in the circulation circuit so I can sort of calculate how much inhibitor and antifreeze to add, depending on how much protection I think I need.
Probably simpler to fill the circuit using a measuring jug though.

How to surround the pipes that drop cold water to the bottom with that nice pink hi temp foam as I do not need any cold flows running through the top part of the heatstore ?  Expanding foam is always entertaining.  
Turned out to be nearly impossible to create a former that would allow me to inject expanding foam into it and end up with a uniform thickness of foam around a pipe.
Might have worked for a totally straight pipe before soldering it into the heat exchanger array. I ended up using HT armaflex and clear silicon for jointing.

In order to get the heat exchanger array off the shed floor without it falling apart or breaking a cheap plastic leg, I gave it lots of triangulation and strapping, using stainless steel tying wire ( left over from the last bridge I helped to build ) and some green polyprop chord that I found.  I set up a hoist on a beam that just happened to be more or less above the array, chose four sling points and gingerly lifted the assembly up. Amazingly the contraption seemed to be quite robust and rigid so getting it upright was less stressful than I expected.
Once upright, I was able to do a few final checks and with a re-sling to give a vertical lift,  I was able to roll a bike trailer under and strap the array on. So far so good.

The assembly looked really lopsided on the bike trailer with the thing looking like it was leaning a lot more than tolerances would allow. I had not checked the geometry of the legs during assembly and had relied on two templates and visual checks.
I ended up jacking up one side of the bike trailer to try and get the bottom of the legs level so I could assess just how far off upright we were. Not as bad as I thought, so I put it down to the very wavy bit of ply that was covering the trailer.

Then I set up lawn protection and positioned the 6 tonne digger ready for the install. Various sources of help were possible, including four fit and strong young chaps travelling back from a gig in Belfast and another friend who had threatened to 'show up on Sunday'.
Another cup of tea and I decided to carry on on the assumption that I might, or might not, get help. So a careful drive from the shed to the end of the house and everything still looks good so I thought that whilst waiting for help to arrive I might as well try and sling the array and see if I could get it nice and level. I was getting a bit braver with the strength of the legs and decided I would have to risk slinging near the top so I could get the slings off once the array was in the pit.
After several minor adjustments on the different length friction tie downs, it all looked quite tidy so I thought that I would offer it up to the hole just to see if it fitted.
Not so easy on your own but I thought that if I tied a bit of rope to an appropriate leg, I could tinker with the rotation from inside the digger cab.  last time I tried this trick, I ended up with an overturned  15 tonne Hymac and a completely wrecked shutter but I was only going to check the fit whilst waiting for help ...
Yeah it looks good, perhaps I could fiddle it in without help ??  So after a few nervous moments and several in and out of the cab circuits, I eventually got the whole assembly in the pit with clearances all round just as I had planned. Phew !  Hi Andy, thanks for coming mate, your just in time to help me unsling the tie downs.Yeah.

The next day I slowly filled the pit with some magic water ( didn't want to stress the tank by quick filling ) and noted a small leak in one of the olive/ compression  connections in the top radiator. I had left the incoming heat circuit pressured up and on test. It had dropped from 30 psi (2 bar) to 9psi in a week, so I jacked it up to 30 psi and got a spanner onto the well rounded nut to try and nip the fitting up, to seal it. The water was absolutely freezing and my arms went bright red from being immersed.
I bl00dy hate those olive compression fittings, although theyve become a bit more reliable since I listened to Lord Frot and try to ensure the pipe is not rammed fully into the fitting prior to tightening.

I tested the two 10mm tubes that I inserted behind the thermalite blocks in the pit, because now Ive finally stopped dewatering the area around the concrete sections, both layers of waterproofing are under test. The test was simple enough, suck or blow to see if there's any water got to the bottom of the tubes / heatstore. Suck gave a strong taste of styrene and blow felt smooth and un-restricted. So far so good.

Also, I had to organise some reliable underwater temp sensors, cos once its all in the pit I will not want to revisit the plumbing. I found some cheap hand held thermometers with probes on the end of a meter long wire at  www.thermometersdirect.co.uk    and ordered 5.


Being curious, I decided to do some heat testing on various types of insulation.
I made a little nest with some aluminium sheet and tinkered with the heatgun to see how stable I could keep the temperature.
It was pretty simple and it was possible to keep the temp to within a couple of degrees as long as nothing moved.
The kebab in the attached pic shows four different types of insulation that seemed quite happy with a temp of 180-190c for about 10 minutes.
From the bottom there's Navitrons HT armaflex, then there's a bit of ordinary black class 'O' armaflex, then a small chunk of fire resistant ( nice 'n pink) expanding foam and at the top there's a chunk of ordinary green expanding foam.
I also had a loose piece of cellotex foam in there for a while but it got away. The HT, class 'O' and the PU foam all seem to be able to withstand a temp approaching 190c for approx half an hour. I felt I should stay below 200c because that is apparently the limit of the thermometer.
The cheap grey B&Q pipe lagging failed at 90c and simply reduced in volume to become a small lump of congealed snot. Polystyrene was not a lot better.

So fired up with the success of this hi tech testing, I went indoors to re-do the hot / warm / cold flow tests on the Toolstation TMV, especially now that the nice lady at ToolStation has explained to me how that yellow cap is not an adjuster, its a lockshield that has to be removed with an allen key !   Well she did have the advantage of a complete boxed TMV with instructions and an allen key (-;
I didnt need to tell her about removing the non return valves though, although they were a bit reluctant to come out .....
This time I was able to tinker with the temp adjuster on the TMV, whilst flowing various temp water through it 'backwards'. The only thing that concernd me a bit, was the possible restriction to the quantity of water that can flow through the valve.
It would appear that this TMV has the potential to act as a thermostatic diverter valve, with the option to vary the divert temp all the way from cold to 62 deg c.
Which is pretty much what I want it to do.

[noelsquibb]

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[noelsquibb]

Heh

I see Ive managed to unbuild the veranda 
I thought I built it after the underground pipework was completed
oh well, it seems to have re materialised since installing the heat exchanger array...

[noelsquibb]

Stunned silence or bored indifference ?

I dont want to spend time writing this project up if Im the only one reading it 
Should I assume the former and keep going ?

Perhaps theyve all gone t' pub, I mean, it is Saturday night.

Yeah that'll be it. Ill go and see.....

[desperate]

OI get back here,.................                 here we are waiting with baited breath,  running out of bates fast, and you go skiddadling orf to the rubbadub, at least you could bring back a coupla bottles

Desperate

[KLD]

Noel, keep going. PLEASE!
I'm sitting here in awe. Your latest laboratory setup for testing the reverse behaviour of a TMV is brilliant! I can't wait for the verdict of how well it all works 

Cheers
Klaus

'Old Peculiar' in front of the woodburner tonight. At least 23°C in here. Got it all wrong and went to the pub last night with the family 

[Stuart]

defiantly watching quietly!

[daftlad]

You're a loooooonnnnnnatic, brilliant.
I missed this one at first, coz I was away, more more more MORE.
ta ta

[frotter]

I can vouch for Noels tinkering awesomeness, as he has sat and supped Frotdor tea a time or two. I totally nicked the reverse TMV idea from him - works a blimmin treat!
I sense some forthcoming appeals for help from forum nerds with the setting up of lektroniks, int that right, Noel? 


 

[noelsquibb]

Im having to have a lovely hot deep bath every night cos my Wife seems to like having the fire lit and theres just sooo much hot water. Sorry not to have got back sooner.

I sense some forthcoming appeals for help from forum nerds with the setting up of lektroniks, int that right, Noel?

err probably, especially if I knew what lektroniks were...

Anyway class of five, do I have your attention ?

Some theory. What I wanted to achieve in slightly more detail -

Three separate sources of heat-

1. Woodwarm Fireview WBS - 12kw max output.
2. 30 x 47mm  Navvi Solar Toobs - total output still under discussion (-;
3. Oil Combi boiler

any or all of which can contribute to the heat harvest at any time,
The WBS circuit is reduced to 22mm once away from the fire, cos that's the size of the pump fittings. The solar circuits is 15mm from pump to panel on the return then 10mm on the hot delivery, combined at the heatstore with the incoming flow from the WBS, diverted down to a lower radiator if only warm, on down through the radiators in the store and back along the combined 22mm return line to split off in the control cupboard and go back through the WBS or solar panel as required.
Ok, that's 3 pipes in the underground duct box, 2 of which combine just outside the heatstore

To recover the stored heat there are two 'coils' of 22mm copper that take cold / cool water straight down to the bottom of the heatstore in insulated pipes then wind up through the heatstore collecting heat. There's about 18m of pipe for the DHW and 12m for the CH circuit.
So water on its way to the combi boiler is diverted through the heatstore and if hot enough will be diverted past the combi, to go directly to the hot taps. A normal TMV in this boiler bypass loop in case its too hot for safe use.
This idea was copied from - http://www.atmos.uk.com/core_files/productDoc(114).pdf   and was what got me thinking about using TMV's backwards.
Any spare heat to be utilised by pumping the CH circuit through its heat exchanger loop that terminates about a quarter of the way down the heatstore.

Now a lot of this had to be nailed down quite early on because there is no easy re-hash if it aint quite right, what with that heat exchange array, buried pipes, pipes under decking, pipes hidden behind large pieces of wood that look like structural timbers, its quite daunting to commit to all this, when I'm a novice regarding the whole caper. Ok I've done plenty of plummin but there's no one whispering in my ear that it'll be fine, that's why I came here.

And what I did get was a huge amount of snippets of info that gradually built up a comprehensive picture, gems like Mick Bees stagnation page on the Navvi Wikki -
http://www.navitron.org.uk/pmwiki/pmwiki.php?n=Main.Stagnation  insulating exposed pipes above roof, high level vents below the roof, potential for very high temps within the solar loop, sizes of EV's to cover the worst likely situation, all of it hoovered up and incorporated into the planning.
The heat dump beat me though, because I simply could not get 28mm rising pipework to a big rad somewhere out of sight with no pipework  or radiator visible.
There seemed to be a consensus that a big enough heatstore would take several days of sunshine and that it rarely shone all day every day for weeks plus we don't do holidays, cos we live in a fantastic area and just never got into the habit. ( now there's a lame set of excuses for ignoring basic safety )

I read in the handbook and on the forum that the new woodburner doesn't like the water coming back too cold. I think 54 deg c was mentioned.
By the time my very hot water has done the 30m round trip, plus dropped down through 3 or 4 radiators immersed in possibly quite cold water, its not going to be very warm when it gets back to the fire.
So - fire heats up and stat cuts in pump. Water circulates in short circuit until reversed TMV allows any hotter than 54 deg c water to start its long journey to the heat exchanger. If it gets back too cold and even after a trip through the fire it is still below 54, the TMV diverts it back for a reheat.
Pump runs continuously for as long as the hot stat says its hot.
Basically we are using a TMV in reverse to do exactly what a thermostat does for the cooling circuit in a car.

So that's 4 TMVs then. 3 of em working backwards.

Then there's some non return valves and an expansion vessel, further complicated by the difficulty of linking the EV to both circuits without any bleed-over occurring ( so avoiding pumping heat into the WBS in summer or heat into the solar circuit in winter ). Initially I opted for a pump for each circuit, then, when I found there was no good way of connecting the EV to both circuits, I opted for a 3 way valve and a single pump, all to operate as per hydraulic option 7 in the TDC3 handbook. Then when I went to see the Uber Ginger One at Frotdor, he kindly suggested that it wouldn't work in the way I was expecting, because of all those Td tronik things,  that don't mean nothing to me.
He said 'KISS' and use separate pumps, thus running the solar circuit on hydraulic option 1 and a simple pipe stat strapped onto the back of the WBS to run its pump. Sounded right to me anyway.
Ok this meant another smaller EV for the WBS but it was a whole lot simpler and it allowed both circuits to run simultaneously, on the off chance of the sun shining on a freezing cold day.

Are you awake at the back ?
Do you understand what I'm telling you ?
Hmm thought not.

Basically lots of pipes and quite a few wires.  
An EV that got positioned 3 different ways and a temp probe at the bottom of the heatstore that somehow ended up in the same duct as the power supply.
Hey I knew that.

[noelsquibb]

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[noelsquibb]

Progress,  around spring 09 -

Not really looking forward to it but eventually I managed to connect the pipes and a cable duct through the office wall in the house, so the circuits for the DHW and CH heat exchangers were now complete except for the final hookup in the boiler cupboard. I opted to use plastic pipe because I couldn't see a way of getting copper tube to feed through the series of holes in the studwork, plus curving as it came through the main external walls and again into the boiler cupboard.

The electricians had showed me a simple trick for opening up plasterboard and closing it off with the minimum of work. They did a cut-out of whatever shape seemed appropriate , did the hidden work then screwed some timber strips across the cut-outs and screwed the cut out piece onto the strips. Exact thickness and fit.
Quick splash of easyfill, rub n paint. No evidence of disturbance.

Assembled the mighty 30 tube Navitron collector frame , as per my instructions ( cos they don't seem to come with any ) and noted that it was not going to blend in very nicely with the new veranda roof so I decided to colour co-ordinate it a bit. Not so easy to match slate especially as there's a lot of variation in the slate itself but we ended up with a dusting of silvery grey from an old ford cortina plus a bit of dark green and some purple. I used to do car bodywork as a sideline and still occasionally sort out the odd ding, so mixing cellulose paint is just another bit of fun.

Access you would be proud of, was based on bits of carpet clout nailed onto the undersides of the scaffold boards, all resting on the ladders fixed onto the timber frame ( I told Clive the roofer, not to use rope but he knew best ) Top fixing for the panel was a delight as we only had to lift a couple of 'topper' slates and we could mini coach screw into a doubled up batten , so nothing visible from below. Bottom fixing went down around a slate then bent up under it to almost invisibly fix into the edge of a batten as this gave us a shorter run of strap above the slates.

Set up the comp fittings  to mark out then core cut through the slates using a slow drill, broke one but easy to access and repair because we had deliberately not  done the mortar capping.

Once the holes were formed and the slates all back in place, we set up some strips of timber in order to form the mortar cap. It was around this time we became aware that the entire set of scaffold boards had moved the ladders off the wall a couple of inches with possibly more stretch in the rope to come. Time for the HD ratchet straps but too late to put everything back up the roof a couple of inches, oh well, the mortar cap looks fine.

You can only be impressed by the elegant design of the roof access boards and the sheer number of ladders involved ( one more would have been handy ) and note how careful we were not to upset the emerging grass seed.

Next up ?  well more plummin actually.
Final conns into heatstore for incoming heat, temp probes into heatstore, pipework for solar to control area, then woodify the exposed top bit of the heatstore including top insulation , woodify the drop pipes at the back of the veranda with a shelf between to hide the controls under and sit logs on so nice and dry and close to log fire, install new log fire, hookup, fire up, tinker and err, bu88er off for three months to go and earn some money on a big skool project in Plymouth with an end August deadline. Totally stole my life it did.   Oh well ought to be grateful.

[noelsquibb]

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