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

[desperate]

Noel,

the irony of it, there you are with the steam blast of yellowstone, here I am with the TS of glaciation, and we both end up with trouser fill moments


Desp

[frotter]

Hornets, steam?  Thought my tinkerin was risky..........   

I hate hornets, me. I know theyre fairly docile an all but i'm allergic to waspses and the thought of one o them giant poison-filled lances piercing paper thin ginger skin........   

Nice fiddlin old boy!

 

[Stuart]

Sounds like fun, they should have a Grand designs type programme for renewables. This episode would get recorded!

[noelsquibb]

Yeah Desp,
ironic but as Ivan says, better than a proper fire.
- His story reminded me of a mate trying to put out an under-bonnet fire with his weekly food shop ....

Thanks Frott, Its a lightly trodden path I seem to be on.  I need all the support I can get.

Stuart, I would run a mile from a Grand Designs concept.
All they want is drama, trauma, vast overspend and someone to ridicule.
I could probably tick the boxes though ....
At least on the Navvi forum, I can delude myself that anyone daft enough to read this far, is likely to be sympathetic to what Frott cheerfully calls 'bodgineering'

Anyway back to the main event -


'spect you've all had a few sleepless nights wondering what happened next ?

It wasn't the 'really difficult to access' non return valve that had stuck shut.
No, it was the 'failed the first time it was used in earnest' Tool Station reversed TMV.
This is the component that was meant to regulate the flow temp through the WBS. It was tested and set to divert at around 55c.
So until the water in the fire boilers was at least this temp, it would stay in a short loop and get a bit more heat, only diverting to the heatstore if the water remained above 55c.
It had been tested on three occasions, cos the flows were different to the other TMVs I had tested. 

When I got it out and re tested it in the sink, it completely failed to switch over to the other port when the really hot water arrived, so this fully explained the excitement of burn 1.   
Close inspection showed that something was misaligned but no obvious explanation. My guess is that swarf had got wedged in it during flushing and cold pump flow tests.

I found the paperwork for it, presented it to Tool Stn and they replaced it with a slightly different one that had different body dimensions and threads, doh !
Only consolation being that they had come down in price by about £9 since I bought it, so I got a refund on the difference.

Re-plumbed and on refilling and pressuring, I got two leaks from the three connections, well I was forcing the pipes a bit   
So another strip down and a bit of hi-tech beasting before it finally held water.

The next fire was a bit nerve wracking as the heat built and once again, I had to turn the fire stat down to start the pump but once it all settled down, the top boiler seemed to stay at a steady 'too hot to touch for long' temp and over a period of about 5 hours I got the temp in the heatstore up from 27 / 39 to 41 / 57 these numbers being bottom / top temps. So that's 1400 litres, 2m deep and the temp gradients look good. The input radiators seem to work better than I could have hoped and no noticable leakage of heat into the solar circuit, which shares the input radiators and the 22mm return line.

Next thing was to see how the cold flow diverted through the heatstore, on its way to the hot taps or combi boiler, would work.
The reversed TMV before the boiler was set a bit too cold for household approval.
I had to turn it up a bit which meant it was more likely to be diverted for small top up via the boiler.
This all seems to work perfectly well too, with the Worcester Heatslave oil combi, happily accepting water up to the divert temp and often not firing at all as hot is drawn, so another big result.

The following morning the fire had gone out but the pump was still running. Buggah. 
Apparently a flue stat from BES will sort this, run in series with the fire stat.
I moved the fire stat from the output pipe of the top boiler, to the connecting pipe between the side boilers, as this pipe seems to get hot a lot sooner and should switch the pump in before 'kettling' starts in the side boilers.   

A very smart magnetic thermometer turned up in the post and allows us to monitor the top boiler temp closely. It confirmed that the TMV to keep the water in the boilers up to minimum 55 deg was working perfectly with the circuit only opening fully when the return flow was pretty warm.

This particular fire gave me, from the bottom, 51.2 /53.0 / 56.1 /57.7 / 58.4c, in the heatstore.   
Three days later with no further wood burning the temp was 36.7 / 42.2 which was still a useful boost to the cold flow on its way to the boiler.   
Depth of probes is 0.2m, 0.4m,1.0m 1.5m and 2m. 

Did all the insulation and reconfigured the blow off pipes to vent into the void below the decking, so that in the event of pump or power failure and a good fire going ( pretty likely actually ) the hot water and steam will not fill the cupboard and electrics with water, nor should it remove any skin from someone stood nearby.
I really have to give some thought to power backup though, as the whole system is dependant on working pumps.

Also need to think about ways to improve the heat transfer to the cold flow on its way through the heatstore to the boiler cupboard. If you run the hot tap slowly, its possible to run a bath without the boiler cutting in but we've got used to a combi with enough preheated water to fill a bath quickly. So  if my wife runs a bath the boiler runs while the tap is open but stops as soon as the tap is shut, which is loads better than the 5 minute burn it used to do, to replenish the stored hot water.
This will probably entail splitting the, only accessible, highest leg of the 22mm copper pipe that winds up through the heatstore into 3 or 4 parallel pipes, or possibly a 'tank in tank', if I can find something suitable that will withstand 3 bar regulated mains pressure and reliably connect to copper tube. Not too much room between the top radiator and the water level though, so most likely the parallel pipes first.

So in a sort of semi-conclusion regarding the aspects of the project that were breaking new ground, I suppose the heatstore and input heat exchanger are looking good.
The use of three reversed TMV's to act as flow divert stats looks good, although the temp range of reversed TMVs seems to be from luke warm up to about 60 deg c.  Once opened by hot enough water, they will allower hotter through which is exactly the same as the stat in a vehicle cooling circuit.
The TMV and reversed TMV for the flow divert through or past the combi boiler works ok too.
Also I have to log the results of that first exciting burn in a positive way because the whole circuit was flash tested to 3bar and probably 120c without any apparent damage plus both EV's were tested to blow off and were shown to open their safety valves within a second of each other.

Still got to programme the TDC3 and fit the tubes but I can put that off easily enough cos Im cooking more water than I am able to get rid of )

Shouldn't take long then.....

pics -

naughty reversed TMV ( with yellow lockshield )

posh thermometer

[noelsquibb]

finished heatstore - apparently it has to have a sedum lawn on top  

Tri -iso 10 on top of 100mm cellotex to keep the heat fom escaping out of the top of the store.

dry run for best fit, prior to diverting cold feed through heatstore.
It wasnt going to be easy installing in boiler cupboard.
The two white speedfit connectors were the start and finish of the diversion. The right hand TMV is reversed to act as a divert to or past the boiler, the left one will blend the hot that was diverted past the boiler, if its too hot.  
Gotta keep it safe  

[SteveH]

noelsquibb,

 You have my admiration... That's probably just words of platitude though...

 I applaud you....

 Another step forward in "Conserving the Future"...

 Steve...

[noelsquibb]

Thank you Steve.

Ive been a bit 'down' for the last few days and didnt really feel like updating.
Only 5 hours paying work for November, December not looking much better.
Plummin ? hmmmm  see below
Never stops 'kin raining ......

Had a few good hot deep baths though -



Ok we are getting close to real time reporting and there's still plenty of opportunity for .........

THINGS TO GO WRONG    -

Originally I was going to use  temperature probes and a controller, probably another TDC3, to manage the existing CH circuit and extract stored heat.

So a probe like you get with the solar tubes ( well, exactly the same really ) was planned in and set at 1.5m deep, as this seemed to be a good place to make an assessment regarding available heat.

The plan was to only divert the flow through the heatstore on its way back to the oil combi, if heat could be added. So another sensor or two would be required on the pipes before and after the divert, so there would be no chance of burning oil to warm the heatstore.
I know there's arguments for doing an efficient burn with boilers to charge heatstores but if you go back to my opening statement, this project is about becoming independent of oil.

So when the great one at Frotdor suggested that this was possible but ' a bit complicated'  I knew I needed a plan B ....

Several long hot baths later ( yes we were cooking water with wood by this time ) and I eventually decided that the KISS principle was probably the best way.

On its way back to the boiler, the CH water would be routed through a 3 way valve then, depending on which port was open, it would either go through the heatstore, back to the boiler cupboard, then through a pump and 'T' into the hot side of the CH circuit beyond the boiler, or it would go through the boiler if the other port was open.

In other words its either CH from the boiler or CH from the heatstore.

Ok that's more action in the boiler cupboard, in an area that's already pretty crowded and I've got to pick up two not very flexible bits of 22mm speedfit pipe, which makes the three way valve the key component.
I've learned that you look for the hardest bit and get it done first then do the next hardest connection, leaving the easiest bit till last.

I often see major projects where they've targeted the easy bit 'to make a show' and I know that we will be struggling to do the hard bits at the end, usually with a deadline looming.
Identify the hard bit and get it done soonest. It will be the key that unlocks the whole job.  ( sorry, didn't mean to get up on that little box )

Anyway, I just happened to have a spare three way valve as a result of a previous visit to the 'donut o delite' for tea and teknikal advice and after a bit of research, that involved bare wires and live feeds, I learned that to get the valve to fully open, you join the grey and the white together and energise them.  I also discovered that the orange is a switched live that goes live once the valve is fully opened, which made it ideal to use as a feed for the pump.
So that's port A open when there's no power to the valve and water routed through the oil combi, or port B open when the valve is powered up with the pump cutting once its open and the water routed through the heatstore.

So in went the three way valve, the pump and a non return valve on the boiler CH output, in case the new three way valve ever plays up.
Also took the opportunity to put in another half litre of inhibitor as I filled the extended circuit cos I like inhibitor.

Easy enough to fill and flush using the existing CH filling loop but disappointingly difficult to pressure up.  Oh dear there's got to be a leak in the new plummin that goes down into the heatstore but how is that possible when I pressure tested all the copper pipe to 5 bar, as I built the circuits up and now I'm only asking for it to hold 1 bar.

Uh - oh, times up. Wife home.   
" Yes, all done, just clearing up " .... " so can we use it for heating then ?"  " err, not yet, got to balance it all up, hopefully tomorrow " ( if you are not here )

The next day was another wet one but plummin beckoned once more and I had two possible places to access in the hope of finding a leak.
The first one was the top of the heatstore where the heat exchangers connect to the built in pipework using compression fittings, in case I need to remove them )-:
So top off, plastic sheeting off, space blanket off and I cant get the cellotex sheet to move at all and it looks like the small amount of expanding foam I used for the final seal, has continued to expand and the whole sheet is firmly wedged. I ended up using a garden spade to work around the sheet and eventually it released. The foam had apparently come back to life and expanded a bit more as I had lifted the lid before.

Five observations -

The 'water' level in the heatstore was down about 6" from its original fill up level.
There was lots of black flaky deposit, like you get if you plunge red hot copper into cold water,  floating on the top.
The copper pipe that was still immersed in the 'water' looked very coppery and new in places.
It stank like a nasty acidic chemical reaction.
The class 'O' Armaflex I had carefully teased onto the cold feed to replace the 'HT' Armaflex, had swollen up and abandoned the pipe and looked like a large dead snake.

Really not good then.

The connections all looked solid and firing up the little electric tyre pump in the boiler cupboard, to identify a leak, showed nothing.

So, time to get the old Subaru fuel pump out and see if there's anything can be pumped out of the insulation layers.
Yup,  about 4 buckets full before we started drawing air and its got the same whiff about it as is emanating from the heatstore.
Pretty cold to touch though so not much heat tracking through the insulation.

Bu66ah, that's the GRP layer failed then and no way of knowing if its one leak or if its become porous, cos it doesn't like the hot wet environment but maintained level for three months in summer when the water in the store was cold.

Ok lets try and find that plummin leak -
Moved the big potted bush thingy, stripped down the timber covering on the pipes rising vertically up the outside of the house, cut open the tri iso 10, cut back the HT Armaflex and exposed the speedfit elbows that connected the rising 22mm copper to the horizontal 22mm speedfit plastic that I had to use to bend through the internal wall and there it was bubbling away!
The simplest connection you could get and I had simply failed to push it onto the vertical copper pipe far enough. Also the only fittings that didn't get pressure tested because I had filled and bled all the copper outside the house and didn't want to make a mess testing the two bits of speedfit and the elbow connections.
Well they weren't going to fail were they .......

So connection made good, circuit refilled and bled and pressure tested to 5 bar. Looking good, connected up and filled to 1 bar and the valve opened up to
equalise pressure with the rest of the CH circuit. Sorted. Pump running and warm water going to the radiators. Phew.

Back to the heatstore and all that black flaky stuff had gone, probably knocked down by the rain.
I took the opportunity to put a knuckle bend on the 10mm pipe that I used to pump out the insulation layers and extend it to the outside of the heatstore.
Then topped up the water and put the insulation and cover layers back on.

So was it all just a bad dream ?

Nah, I forgot to put the potted plant back in its corner. Doh !  what a useless twat I obviously am.

Ok, this takes us to about two weeks ago and rather than leave things on a low note I will keep going -

The 12 kw Woodwarm Fireview has been kept going 24/7 and while burning a well filled barrow of dry hardwood a day, is able to keep the house as warm as we would have it normally and supply all the hot water we need.

Which is exactly what I hoped it would do.

It only just held the temp in the kitchen-diner at 18-19c when we had an overnight frost, but generally can just about maintain 20c in this room.
The water in the radiators is only about 45-55c but with constant pumping we can just about get enough heat from the rads to replace the heat being lost.

We drive the woodburner by monitoring the magnetic thermometer stuck on the top boiler. Between 60c and 70c seems to be the magic numbers to keep everything balanced. So quite a lot of the house gets warmed by direct heat from the WBS and the furthest rooms get indirect heat from the heatstore.

Having the CH pickup loop in the bottom two thirds of the heatstore seems to be working ok and around 9.00 in the morning, when I might get round to stoking the fire, the temps in the heatstore will be around 60c for the top third and 55c- 45c for the bottom two thirds, with an obvious step up in temperature above the CH pickup loop.

I will try and write up a few more observations and float a few questions soon as there's still plenty to consider.

In the mean time, I've serviced the 4.5kva diesel genny and am about to build it a permanent shedlet, so it can be accessed and fired up quickly in the event of a power cut. If it ever dries up, I might even dig a 'pit o doom' to shut the exhaust noise down.

A more permanent solution to mains power failure may come from the stream that's rushing past the log shed.

But if anyone knows why the water in the heatstore has gone bad ( pH down 2 units and electrical conductivity way up ) and what I might add to it to neutralise those nasty niffs .........

I would be extremely pleased to hear from them.

Oh yeah and theres the toobs .........

pics -

oh dear 

[noelsquibb]

hidden speedfit connection

pumping water out from insulation layers

look at all them pipes valves pumps wires n gauges eh ?  retro fitting is never the easiest way though

[noelsquibb]

indoor temp, outdoor temp and the exact time in Germany

temp range in heatstore

fire boiler temp.

sort of average readings in the morning once the fire has been topped up

Dunno if this makes any sense ......

[Stuart]

I suspect there is some chemistry happening between the iron rads and that warm water, a bit of atmospheric Sulfur dioxide and you get acidic iron sulphate which will start eating the copper too

dig the pit bigger and fill it with oil? mmm.....oil pit

if it was air tight maybe some fernox would help....will a nice auto antifreeze mix in that pit be more stable?

[lightfoot]

Noel - with regards to your stinky store - a couple of things spring to mind that maybe worth looking into, ie; there maybe some galvanic reaction between the dissimilar metals in the store - leading to corrosion etc (which will be accelerated by any dissolved oxygen in the water and open vented systems are more prone to this than sealed systems).  There may also possibly be a slime build-up due to biological contamination?  Have you used any/sufficient inhibitor etc? 

Here's some more info....

http://www.fernox.com/?cccpage=break_down_guide&sub=2

http://www.plumbingpages.com/featurepages/WaterProblem.cfm


Good luck,

LF.


PS, One other thing - I don't know what type you used - but some GRP resins etc may not be suitable for high temps and chemicals etc, and may well breakdown over time causing your leak.....or you could be just losing water through evaporation?

[frotter]

Blimmin eck Noel! This is top tinkerin and no mishtake......
Your store does look real nasty though...   Whether you can permanently stabilise it has to be a worry. In the short term i would treat it like a particularly pickled H*t T*b and treat the water with a bit o bromine to kill any lurgies and then try to keep PH balanced to protect your precious copper. Caustic soda would work, then use pool/tub test strips etc.
Maybe really strong anti freeze or inhibitor...
Wot a pain though!

Pff!

 

 

[wexford]

Maybe see if someone nearby keeps fishes. They would have a water test kit that will tell you PH, ammonia, nitrite and nitrate.

That'd tell you if there's anything biological going on or rule it out. As Frotter suggested bromine would work or a mild bleach to kill anything biological. . PH can be adjusted up or down by using caustic soda or vinegar. Have a look here for ratios. http://dataguru.org/misc/aquarium/calKH.asp Again a fishkeeper will be able to help with KH readings. Checkout buffering (as in PH buffering), coral chips are supposed to be good .

Wexford

[frotter]

You might also want to check there int a gert conger eel lurkin down there - conger poop is well known to be highly corrosive! And mind yer fingers.......

 

[desperate]

Jeez Noel, I reckon you should fill up the biggest teapot and flog it to the local builders, Seriously though, I fear your rads in the store are acting as sacrificial anodes to protect the copper and unless you can exclude the oxygen an inhibitor will gradually loose it,s protection. Do you think you could make the cover reasonably air tight? Or worst case scenario make a new heat exchanger all out of copper, possibly a coil of soft 22mm? I',m just sort of guessing really it may be sommat real simple.

Desperate