[Closed] Calling wood fired central heating experts

Couple of options

1 a thermal store heated from gas / stove plus solar thermal etc. if required, used to run ch and hw
2 dunsley neutralizer http://www.dunsleyheat.co.uk/linkupsys.htm

I've gone for a small 300l thermal store

I did draft long post about thermal stores and call-for-heat and hot water cylinders etc, but there's also ,I imagine, fangled widgets that handle things too.

Although I reckon Im not bad at some of this stuff, your particular problem I think is out of my comfort zone.

Bear (of this 'ere parish) might be your man though.

Evening! Stoner don't put yourself down you know as much as me. I just have a practical approach and experience.
Surely a pellet boiler is automatic. Believe there is a pellet / log boiler unit. Uses pellets to light logs boiler which charges accumulator then if more demand needed then pellet kicks back in.
Can also link gas boiler in though. Give me an idea of what you are heating.

B - I think the OP has a back boiler CH system, so is talking about adding a boiler to do call for heating that augments a back boiler set up.

A thermal store obviously deals with buffering and multiple sources but I imagine there's also kit out there that can deal with a call for and a back boiler without a big water store?

Hi,
Thanks for replying. I currently have an aarrow wood burning stove with back boiler which burns logs, and pretty much anything else I feed it. Bought a few years ago before pellet boilers became all the rage. The back boiler runs about 12 radiators (there's a pump). Hot water runs off a separate system.

I need something which I can use to get the house warm quickly on cold mornings and which will warm the house in spring summer when a full on log burning session seems a bit like overkill. I think that a combi burner needs a pressurised system and I am pretty sure that is not what I have (there's an expansion radiator) but I don't want two lots of radiators which has been suggested. Will a conventional boiler do the job?

Ps I am heating a stupidly big house built out of Yorkshire stone. I bought it by accident but that is another story.

As above densely neutraliser if not using a thermal store or accumulator. Not sure a buffer would be the right thing with a log, you really need to be able to store all the heat that the stove can produce.
I'm sure with pipe stats etc and motorised valves you can do an automatic arrangement. Think you need a normally open valve in the system to make sure in the event of power failure you can get rid of the heat from the stove.
Probably best gravity to a thermal store with pipe and cylinder stats to control gas boiler.

I've never heard of a thermal store before. Where did you get yours geoffj? And how big is it - where in the house have you put it? Does it have to be on the ground floor?

I can see the benefits that you can add on other heat sources as funds allow (currently self-employed and weathering recession by living on air but would dearly like to add some solar panels to set up eventually) but if you're not using it for hot water does that reduce its efficiency?

I have a header tank on my central heating so that's one tick.

I assume your CH circuit feeds, expands and vents into your header?

How is hot water done? Single point of delivery?

Thermal stores can be quite heavy, my preference would be ground floor, but if the joists are rated for it, then nothing wrong with having it higher in the house. Help with gravity feed if you did.

My thermal store links my solar panels and my biomass boiler and then all my CH and DHW needs come off it either directly (Rads, UFH) or indirectly, DHW at the taps @ mains pressure.

Theres no problem not using it for hot water as well, although why wouldnt you - esp if using solar thermal heat during the summer - free hot showers.

geoff has his linked to his back boiler via a load charger which would be a good idea.

[i]I've never heard of a thermal store before. Where did you get yours geoffj? And how big is it - where in the house have you put it? Does it have to be on the ground floor?[/i]

Its just a big hot water tank, but you don't use the hot water in it, rather you use it to heat the radiator circuit and there is a heat exchanger for mains pressure ho****er.
Ours is a small 300l one which lives on the ground floor.

Have a look here - http://www.plumbingpages.com/featurepages/HWdpsThermstore.cfm
and here - http://www.soloheatinginstallations.co.uk/thermal_stores.htm

curiously i need new heating in my gaff and im curious - issue i have at the moment is i do not use the heating - which in turn means i have no hot water due to current set up i need to have the heating on first thing to heat the hot water - PIA to go around and turn all the rads off and on all the time and some dont even have valves on.

How does the thermal store idea get round this ? Presuming we just had a back boiler and a oil fired boiler of some kind driving it - could i have hot water without having the heating on.

im being driven more and more towards a combi at the moment ! especially as currently i have to wait an age for a trickle of hot water with zero pressure ( hot tanks entirely lower than the taps !)

which in turn means i have no hot water due to current set up i need to have the heating on first thing to heat the hot water

trai_rat - your system really ought not need to have the heating on to get DHW. there should be a valve controller somewhere that heats your hot water tank from the boiler but doest divert to your rads.

How does the thermal store idea get round this ? Presuming we just had a back boiler and a oil fired boiler of some kind driving it - could i have hot water without having the heating on.

Yes. Much like how your system currently ought to operate, the pumped supply to the rads only comes on when a thermostat says so. Meanwhile a tank thermostat calls for heat when it needs to top itself up. That hot water can then be used at anytime to indirectly heat your DHW water, or directly to your rads via the pump. Also, whenever the back boiler is running it will heat up the water int he thermal store, allowing you to use it for either the rads or for DHW.

A 300 litre thermal store won't give you much time without a heat source IMO. I have a [url= ]1500litre thermal store [/url]and it'll only give a day max in cold weather and that's with the heating system hot.

Having gravity fed may be a problem with a large thermal store as that's a hell of a lot of water that'll expand and contact with the heat, unless youe F&E tank is big and has a good capacity. I've got a closed system and the [url= ]expansion vessel is pretty big[/url].

stoner - my boiler will not fire unless i turn on the heating system.

so unless i walk round the house turning off all the radiators at the dial i have to heat the house to get hot water

or use the immersion

its the old case of never buy a mechanics car. - the geezer was a heating engineer .....

Stoner, the CH is fed from the header tank but has a separate expansion radiator below the header. There's a pump which circulates water round the radiators which is a normal central heating system pump.

Hot water is on a separate system (Aga 😳 ). The Aga loop keeps a bit of the house constantly warm - it would be unbearable without it plus it takes quite a lot of effort to empty the hot water tank. This thermal store thing makes me wonder whether you could link the Aga in too.

Thanks for the links geoffj and Dobbo. Will look and digest contents.

This thermal store thing makes me wonder whether you could link the Aga in too.

yes you could.

If you have a big enough place, you could link your back boiler, oil boiler, solar thermal and Aga to it to make the most of various heat sources as and when they are in surplus, and the Oil boiler when other sources arent running and you need heat for DHW and/or rads.

I have a 700L thermal store, with another 200L in the boiler itself.

Jaspi make some large stores that can take loads of indirect coils.
http://www.northmangroup.co.uk/Oval.html

If the Aga is gas or oil that modulates to maintain the load unless you have demands that can't be met by the Aga then I wouldn't store heat from it, you'll load the Aga up to have heat sitting in a tank that might not be needed. I'd use a thermal store to store up excess heat from wood burner or as a buffer for excess periods like a small store on a heat pump to smooth out demand fluctuations. Not that I'm an expert, just how I kind of see it!

I'd throw the bloody lot away and buy a pellet boiler.......

Sorry Bear I am too poor! Waiting for the recession to end so that people actually buy the things we make again 😕

Need a medium term solution so that we keep warm in the meantime. Was looking at boilers and hoping to get a good deal under 1k. Thermal store as well might not be realistic thinking about it.

The Aga is ancient and came with the house and runs on coal. Sigh. But it makes nice dinners.

My comment was partly sensible too. With all the money you will be spending on configuring your system to work properly and safely you may be better advised to think long term. Bite the bullet for another year or so, or do it in stages, add the thermal store first (which you can dump Aga into) then see where you are in a year or so as to what alternative fuel source you choose.

Take it you are up north then?

Coal = northern affliction 😉

Also manufacturing 😉

Yep, up north.

Funny that bloke who did my biomass course was northern, left a funny black dusty trail wherever he walked....

How about a cheap air/air air-con/heat exchanger. The DC inverter ones perform reasonably (similar to burning gas) unless it's below freezing outside in which case you could fall back on the wood burner.

Not sure I'd like to put a heat pump into a system designed for a higher mean water temperature.

Cheap? Last time I looked one the right size worked out at £6k but if they're now cheaper please can you point me in the right direction? Cheers

for that money buy a pellet boiler!

[url= http://www.bricodepot.fr/saintes-saint-georges-des-coteaux/node/1223099 ]Airton[/url]

Airton is Brico Depot's own brand. Brico Depot is owned by the Kingfisher group. Kingfisher owns B&Q, try the B&Q site. They're popular here in SW France where the outside temperature is warmer. They work down to -15°C at which point they are little more efficent than plugging in a convector. In a well-insulated house they're all you need.

I don't use one but have friends here that heat the whole house with a basic 3500W air/air. I also have German friends that use a much bigger air/air of the £6000 type, the last time I visited it was -16°C and the house was OK - mainly due double/triple glazing and excellent insulation.

[url= http://www.bricodepot.fr/saintes-saint-georges-des-coteaux/chauffage-production-deau-chaude/pompe-chaleur/pompe-chaleur-air-air ]And the cheaper ones if you only want to heat one room or have an exceptionally well-insulated abode.[/url]

I don't use one but have friends here that heat the whole house with a basic 3500W air/air.

In a well-insulated house they're all you need.

I have realised that a small amount of automatic heating will make a vast difference in my life.

Not designed to work with a radiator system using a flow of 82 and return of 71 deg C then?

Air/air costs a half to a third of the running cost of convectors. In France that makes them competetive with gas but in the UK gas is cheaper. They also mean one less standing charge and no annual service charge on the gas installation. Better are the heat pumps that use ground heat, efficiency is up to 480% but the investment is 12 - 15 000e.

The Sapservice thing is great but a simple start is to look at passive house standards for your climatic region and aim for that.

but a simple start is to look at passive house standards for your climatic region and aim for that.

Well for the UK you'd need an R7 roof, R3-4 walls and an R3 floor. R7 being about 350 - 400mm of rockwool/polyester/hemp etc. Google passivhaus or passive home or passive house or la maison passive or... .

I think that before the OP goes rushing off to do that it might be a good idea do try and work out what the starting point is, don't you?
Passivhaus might just be a bit of overkill too, no? A wonderful, yet quite expensive, solution.
And you forgot to mention windows. 😉

"mew"w better than 1.6 for the windows. Mew isn't on my keyboard and it's too late to hunt for it on a copy/paste symbols site. Standard double glazed on windows that get sun. Triple on north facing windows but there we really are talking big bucks. 😉

Passivhaus = overkill, or the minimum?

Edit: and yes the start point would be useful.

May I remind you energy cannot be created therefore heat pumps are not 480% efficient.
Marketing rubbish.

When the OP thinks

I have realised [b]that a small amount of automatic heating will make a vast difference[/b] in my life.

RE GSHP - They can operate at a cop of 5 which means that for every 1 khw of electricity used, 5 khw of heat is produced, the "missing" 4 comes from the ground loop. Colloquially it would be reasonable to say they are 480% efficient.

1kW of electricity consumed consumed, 4.8kW of heat for the house of which all but 1kW from the ground. So you get 4.8 kW of heat for 1kW consumed. I don't know how you want me to describe that in terms of efficiency but it's certainly not marketing rubbish.

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Has the OP even got a garden? 😆

So looking at your links, Don. If Clover wants to spend around £1000 then my suggestion of an air/air heat pump rather than gas for automatic/on-demand heat is valid, especially if it's mainly used when the outside temperature is positive - havin g first looked at how cost effective insulating might be.

I did the assessment using my house measurements and came up with 24kw gas boiler requirement.

Passive house is beyond budget - and would need adapting for 200 year old Millstone grit laithe barn farmhouse. For which I have only just obtained planning permission for double glazing (listed).

During the winter wood fired heating is the way to go but now it's too much hassle to raise the temperature by a few degrees for a short period. Something automatic for winter mornings would also be bliss - the frost on the inside of the windows is pretty but slightly impractical.

Following links now...

I have fields!

Yes, why not edukator? If it fits the OPs bill. With a bit more info, the problem is a problem of warming up the living space while the woodburner is warming up (too much repetition...). There are limitations on the insulations due to the nature of construction and listed status.

For which I have only just obtained planning permission for double glazing (listed).

edukator - we've done this before, passivhaus is all well and good, but it is completely impractical as a retro fit solution to an old building.

yes maximise insulation and draught reduction, but there's no way you can re-fabricate a gritstone building (or an 18th C barn) to have 0 vent loss, maximum solar gain and tiny U-values.

Your 1kw of electricity produces 1kw of heat. The rest is solar energy stored in the ground. If you can make 5kw of energy from 1kw of electricity then you are the messiah!

You use 4kw of heat to heat your home. Most of that is produced by the sun the electricity is used to convert it.

Your 1kw of electricity produces 1kw of heat. The rest is solar energy stored in the ground. If you can make 5kw of energy from 1kw of electricity then you are the messiah!

You use 4kw of heat to heat your home. Most of that is produced by the sun the electricity is used to convert it.

You are being incredibly pedantic (and probably wrong as much of the electricity is used in pumping etc), where you only have to pay for 20% of the energy used, it is a perfectly reasonable claim. Only other solar and wind can make an equivalent claim.

pedantry aside, Im still not convinced of those high COPs in ideal conditions let alone for the majority of the time.

but there's no way you can re-fabricate a gritstone building (or an 18th C barn) to have 0 vent loss, [b]maximum solar gain[/b] and tiny U-values.

I heard they cost an arm and a leg, and I wouldnt trust the importer 😉

pedantry aside, Im still not convinced of those high COPs in ideal conditions let alone for the majority of the time.

I have see higher audited ones, albeit taking into account cooling for modern buildings, cops of 4 are being contracted for by providers on big builds.

[s]I don't[/s] I've heard that that particular importer doesn't do wooden shutters. 😛

No I'm a realist. I fit heat pumps too, they are massively mis sold which is one of the reasons that the RHI payments have been with held.
To even suggest fitting one in an old property with radiators is ridiculous.
They are sold as being 400% efficient etc which is a lie. You cannot create energy surely tat is a basic law of physics.
Pumping usually accounts for a fraction, modern grundfos pumps tell you the energy usage on the front. Most of the electricity will be used raising the domestic water temperature probably.

And pleased with the pedantic tag too!

I have see higher audited ones, albeit taking into account cooling for modern buildings,

thing is it should be immaterial what building it's installed in, its a simple calculation of net energy gain. How it's used can be maximised for the building fabric.

I just am very sceptical of what the average COP of the system would be over a day. I doubt it would be within 75% of the cited COP.

And of course it's pegged to elec costs. big bad in my book 🙂

They use less paid for energy than they produce that is what people in the real world care about, RHI isn't being withheld although take up across the board has been much lower than DECC anticipated mainly because both GSHP and Biomass simply do not financially stack up against gas unless you make pretty heroic inflation assumption. With the possiblilty of shale gas keeping gas prices low, it is difficult to make those assumptions.

EDIT: Cops are calculated by comparing actual metered heat to actual electricity usage so real world numbers and cover the whole day.

If mains gas were an option, Id never recommend going for an alternative energy source (except maybe solar thermal added to a tank).

Gas will be cheaper for at least the next 20 years IMO.

Its Oil and Elec which are the ones for renewable to beat. Its a smaller market than the whole UK, but its still a big enough market. And the reason Im training up to get into it in 3 years or so. Round these parts (rural worcs) Oil fired CH/Agas is the norm. Its a big market to to have crack at.

Its a big market to to have crack at.

Too small for me, but then I only finance this stuff that is why I am focussed on the commercial sector as I see very low take up in the domestic market for a few years yet.

mefty, mind if I pm you. There's a business thang that may be of interest to discuss with my "other hat" on.

No problem

The geologist in me says that ground heat is from both solar warming and nuclear fission.

In my friends house with a heat pump the ground water is 10-12°C and the under-floor heating runs at 25°C or less. Why should he doubt the COP claimed?

If the house is millstone grit how about insulating walls on the inside. Use 90mm of recycled polyester behind 22mm pine floor boarding for R3 (with the wall) or rockwool backed plaster board or even a multi-layer insulator behind wood or plasterboard to reduce the interior space lost to 7cm.

Polyester is about £8/m2 and pine £6/m2. Not to all tastes but it looks and feels cosy. Do something with the walls, double glaze and make sure there's 350mm of insulation in the roof and you won't need a 24 kW boiler.

ASHP are not eligible for RHI domestically yet because the jury is still out....

Stoner - domestic Biomass will be a good field to be in I think, providing the current commercial RHI doesn't do a solar on us........

TBH I think in many cases biomass can be justified in spite of RHI not because of it.

Its those dammned expensive Windhagers that need it 😉

Hello, I think I am looking for a gas boiler + either a heat store or a dursley link thingy then? Where do I find someone on the Yorkshire/Lancashire border who knows about such things?

Anyone on here?

Or anyone who wants a few days of Pennine riding in the Calder Valley?

Clover - recommendations are the best way, personally I would use a store rather than the Dunsley as it will provide greater flexibility in the future. Make sure they understand the controls though.

And yes Stoner they do make sense even without RHI, especially if you look at lifecycle analysis (think that is your thing! Got a couple of spreadsheets that do it for me though!)