Talk:Masonry heater

Old ramblings

I have added the following exchange - can any one add some emissions data for these stoves, and any other useful comcments? Thanks Engineman.Engineman (talk) 05:53, 18 May 2008 (UTC) Bill / Dave O

yes I think it is " horses for courses" , clearly some off grid houses can be upgraded to Dave O's German standards , but very many won't be for the kinds or reasons you state - and these could easily have the Swedish stoves, I think - much better than pellet boilers, or metal stoves.

I agree with you about the pellet boilers in low demand houses - to run at low output they must in effect smoulder, which is inefficient and highly polluting. but in the right application - eg heating the RAF Wroughton hangers, quite acceptable I would have thought.

The great thing, on the face of it, about the Swedish stoves, is apparently that they burn all the fuel at high temperature, (much higher than you can get in a metal stove) and then condense out all the tars etc due to the labyrinth of cold brick they have to pass through on the way out. this accounts for their high efficiency and on the face of it, it seems obvious they must approach 90% simply because the flue gases leaving must necessarily be quite cold. (where else can the heat go but into the house)

I assume the tar condenses, and trickles down into the combustion zone, as the fire cools and is all burnt off next time round as more fuel is put in next day.

Any way, can someone come up with some emissions data?

This is of course a side show - and neither here nor there in the scheme of energy disaster heading our way, but quite interesting as to why we don;t have them over here.

http://en.wikipedia.org/wiki/Masonry_heater

According to Wikipedia, the Swedish version, they were designed on the orders of the Swedish King in the 18C when they were worried about their forests been burnt down. (its déjà vu all over again)

I don't think Dave O ' s comparison with CEGB chimneys is valid - we will be talking of tiny amounts of flue gas by comparison with power station emissions and immensely lower SO2 levels.

The other point to be drawn from this, in my humble opinion, is that comfortable storage heaters can be made, and whilst I agree that hopeless British storage heaters are uncomfortable, I don't see why they should not be made so, along the Swedish stove lines, and used for storing surplus wind energy, another point which David O has not addressed yet.

Dave A

David Andrews

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From: claverton@yahoogroups.co.uk [1]Subject: [claverton] Re: Those pesky Swedish stoves again.

Dear All

1. Yes, these would be useless for the mass of useless British houses, unless upgraded.

2. While radical upgrades as proposed by David are practicable in some circumstances, one often runs into constraints - space, planning, cost, technical risk - and then a combination of a practical upgrade plus a simple, efficient heat source can make sense.

3. But where it also makes sense to burn wood - e.g. with the right house in a rural location off the gas grid and with a local timber supply - then these might fill an important slot for a relatively low-tech, low-maintenance, high-efficiency, reduced-pollution alternative to a normal woodstove. I am not very happy about the capital cost, maintenance requirements, and supply chain requirements of pellet boilers for these purposes.

We need more efficiency and pollution data though.

Bill

On 17 May 2008, at 09:43, David wrote:

Insulate most of these dwellings. Visit Germany; see it happening right now. See past Claverton posting re. a Passivhaus retrofit of a German farmhouse and a reduction in oil consumption (before considering a solar system) from (I seem to recall) 5000 to 500 litres/yr.

Not invented in UK doesn't mean impossible. The house I'm renting while I build my own could easily be externally-insulated, encouraged by (1) bulk contracts (like those used when connecting the UK to N Sea gas) (2) grant aid (as available abroad).

A typical Swedish or Finnish detached house has a peak heat demand of 15-25 kW @ -30 degC. A new UK detached house meeting current Swiss Bldg Regs or the AECB Silver Standard has a peak demand of 3 kW for space heat and say 1 kW for hot water, totalling 4 kW @ -4 degC. A wood fire in such dwellings is near-uncontrollable.

I don't believe 90% seasonal efficiency; show me the evidence. Not even pellet boilers achieve 90% at peak load. Empirically several country people I know who've replaced wood heating in the past by oil or LPG have roughly halved their fuel consumption, suggesting the wood system had nearer to 40% seasonal efficiency. Most wood-burning stoves achieve 60-70% according to SAP-2005 (used to comply with UK Bldg Regs.)

17% of dwellings are off the gas grid. (A few of them might be connected at this late stage or connected to DH if it became available, but the majority are 3-5+ km from the nearest gas main.) Some areas with mains gas (possibly parts of Claverton near Wessex Water, parts of Malvern, no doubt many more) might be too dispersed to connect to DH which is more costly than a gas main. So on checking further the areas concerned might cover nearer to 20% of housing and 10% of non-domestic buildings.

D.

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Original Message -----

From: Dave EU Andrews

Subject: RE: Those pesky Swedish stoves again. Bill and Dave,5

I don’t think these would be appropriate for the mass of useless British houses, but what we are talking about here is surely the quite low 5 -10 % of UK housing ""in the country"" and off the gas grid.

I don’t think David O has given a satisfactory answer - these are houses already built and are not going to slap on extra insulation at this late stage.

Rather than continue to shove wood into a hopeless, inefficient open fire or smouldering stove, the Swedish designs seem to me an ideal solution for the country dweller.

They were not apparently designed by the Russians if you look it up on Wikipedia and translate it

Dave O these things are 90% efficient and so far you have not given any emissions data.

It is evident that they are quite comfortable since 90% of Finnish dwellings have them so I don't think we are going in circles, you have just not answered my questions, (I think)

Kind regards

David Andrews

Claverton Energy Group

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From: Bill Sent: 17 May 2008 16:45

Subject: Re: Those pesky Swedish stoves again.

Dear All

My understanding is that these stoves are most effective in houses which have a tendency to be cold and benefit from a steady source of heat, and where the gains in combustion efficiency more than counterbalance any wastage, e.g. from unnecessary heating overnight. This is certainly what they were developed for.

They can also make some sense in new, well-insulated houses in colder climates (e.g. Sweden and Finland) in which a gentle, continuous source of heat is appropriate. These can do this effectively with short bursts of firing, as already described. So, for example, you can fire them up for an hour in the evening and that carries you through the next 24 hours.

Problems begin to arise:

1. Where you need faster warm-up response. These are partly resolved by putting fans in the units.

2. Where heat carry-over leads to waste (e.g. overnight in poorly-insulated British buildings which do not hold their heat).

3. Where heat carry-over leads to overheating and, window-opening for example, e.g. in lightweight buildings with high daytime internal or solar gains.

I suspect there is also a cultural dimension. For example, they would work best in situations where one was happy live with a fluctuating temperature.

Sue Roaf put one in in her Oxford Ecohouse, but very much as a standby unit I think, as there was also had gas-fired heating. I'll ask what her experience is of it.

With good wishes

Bill

______ On 17 May 2008, at 03:32, David wrote:

Uncontrollable. Developed for almost uninsulated houses in Russian winters, not insulated houses in western Europe. Put yout thermal mass in the building not in the heat emitters.

Dirty (unless you think particulates and PAHs an order of magnitude more than from an oil boiler are clean).

Waste of a valuable chemical fuel. Insulate houses, don't waste solid biofuels on them which could better supply transport sector, chemical feedstocks, gas for glass-making, CHP plant, etc etc.

Sweden has a tiny fraction of the population density of the UK, so can presumably support more air pollution per dwelling without exceding a certain threshold.

As it is, particulates shorten the life of EU citizens by an average 8 months according to medical research. I can't understand why so many people are prepared to risk public health for a gain which is so illusory and could be gained by retrofit insulation, solar and backed up by fluid biofuels.

Read past Claverton postings as this goes round in continuous circles.

D.

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Original Message -----

From: Dave EU Andrews

Subject: Those pesky Swedish stoves again.

Dave () - what is your objection to this kind of thing for use in the country areas, and supplemental heating by surplus wind farm electric?

There Swedish so by definition they must be good.

Kind Regards Dave A

http://www.buildingforafuture.co.uk/summer03/22-43.pdf page 36.

The Scandinavian kakelugn is normally constructed in its simplest form, that is as a space heater designed to perform that one function very efficiently. Tests in Swedish government research laboratories have rated the heating efficiency of these stoves at over 90% and their environmental efficiency at over 80%. They have been granted exemption from the Clean Air Act in this country due to their extraordinary ability to consume practically all of the pollutant normally produced by burning wood and this without the use of a catalytic conversion system. Their impressive heating efficiency is a product of the same factors that allow the stove to consume the pollutants; the high temperature in the combustion chamber, the channelling of the hot smoke and gases around the interior of the stove instead of straight up the chimney, the use of stone with a high heat-retention value and slow release rate and the employment of a damper to keep the heat in once the fire has gone out.

The burning cycle differs from conventional stoves in that the fire is alight for relatively short periods of time, generally a couple of hours. During this period, the wood is being consumed at maximum efficiency with normal combustion temperatures of around 1,000∞C. The fire is then allowed to go out and the damper closed (the Scandinavians close theirs completely, but in this country where we are less familiar with the concept we are required to construct a damper that will only close to 80/90% to allow for the escape of any residual fumes). So the fire is either roaring away like a furnace or it’s out, thus avoiding the smouldering cycle that is inherent in the design of many conventional woodburners, which is both inefficient and produces so much pollutant. The heat stored in the stone and tile mass is then released in the form of long-wave radiant heat until the stove reaches ambient temperature or until it is re-fired. The length of time that the stove retains useful heat depends on its size (mass) and the ambient temperature, but a stove that was alight in the evening will still be warm the following morning and some large European stoves are capable of retaining heat for 30 hours; it goes without saying that more heat gain will be felt in a well insulated building. Stoves built in houses with a lot of brick and stone construction also heat the fabric of the building itself which will contribute to the heat storage capacity, but well-insulated houses of wooden construction have also

been found to have benefited from the inclusion of a high-mass

stove in the heating plan. This stove would normally be built on

its own foundation and travel right up through the house very

much as a conventional chimneybreast would. This produces

a core of comfortable heat as near to the centre of the house

as feasible with the possible inclusion of hotplates, ovens and a

warm seat upstairs in a bedroom or bathroom. As a general rule

of thumb a ceramic stove of average dimensions (about 2m

high and 80cm in diameter) will heat about 150m3, in return for

a daily burn of about 15kg of wood. This is such an effective use

of biomass that over 90% of new Finnish homes have a ceramic

stove of some sort.

The World's Most Efficient Fireplace!

Masonry Heaters have revolutionized the woodburning ethic. They take the same amount of heat expelled through a normal, straight vertical flue and direct it differently - upward over the firebox and then fully downward before exiting through the chimney, which is off to the side. By directing flue gases downward, heat gases absorb much quicker than flue gases exiting normally. During this time is the "charge" period, and usually lasts around 2-4 hours.

Once the fire is complete and all combustion is exited through the main flue and chimney, the Masonry Heater is "shut down". This begins the "release" period of the heat from the Masonry Heater, which can last up to 48 hours, depending on the size of the home as well as exterior temperatures.

There is simply no way any woodstove on the market today can accomplish this task. By utilizing a renewable resource (wood), and gaining up to 90% efficiency over the typical woodstove, Masonry Heaters have earned the "Green" label, giving it distinction in a world where fossil fuels are the most prevalent source of heat.

These fireplaces basically become a "warm rock" in the middle of your home, and emit radiant heat - the best form of heat available. You can stand right next to it and become warm within a matter of seconds!

There is a website for more information on this subject:

http://www.mha-net.org —Preceding unsigned comment added by 75.164.231.78 (talk) 22:37, 17 November 2008 (UTC)

How to assemble...kakelugn?????

I have inherited a family heirloom from Sweden. My Mother brought it back from Sweden and after all these years, it is still in boxes. I would like to add it into the remodeling of my home ,so that her precious items can be in our home. I live in Oklahoma and do not know how much I may use it, but it is sentimental and something I want to add it incase of ice storms which we have had recently. I do not know where to start with the installation or even how to prepare for it's placement. Are there things that need to be added to construction for things such as it's weight, etc.????? Any ideas???? Thanks, Gigi —Preceding unsigned comment added by 72.24.43.98 (talk) 18:45, 23 February 2010 (UTC)

If you search the net "kakelugn ritning" you will find a few drawings of how the Swedish kakelugn is built up (including some pictures of rebuilding one. WARNING; they are heavy with a of of firebricks inside. You need a good fundation) You use clay as mortar. You fire it slowly first time to dry out the clay. After that you put in a fire that usually burns out in an hour or two, when the embers are glowing with NO BLUE FLAMES you shut of the draft. (It is important that there are no blue flames since blue flames mean Carbon monoxide, POISON!) Shutting of the draft completely means you loose no heat to ventilation, also you draw in no cold air except when the fire is going. When it is cold you may have to lay in a fire morning and evening, usually one fire a day is enough. (Be frugal, there is no way of damping the fire safely after it is lit!)

If you go to http://libris.kb.se and search "kakelugn" you will find a lot of literature, sadly only in Swedish as far as I can se.

A Little history: During the 30 yoear war, Swedish officers in winter quarter used to replace the fireplace with a "kakelugn " usually without ceramic tiles on the outside. Visitors usully noted that the rooms were confortabler than the usual german rooms. When they left for next summer fighting the house owner usually replaced the original fireplace, ignoring that the "kakelugn " had used less then a third of the usual wood and had given a lot better climat in the room!

They were standrard in Sweden (today Sweden and Finland) BUT did not spread to Russia after Russia took Finland 1809 even though the Russinas noted how much better the rooms in Finland was heated!Seniorsag (talk) 15:54, 1 September 2017 (UTC)

too much advertising

External links section is pure advertising. I would change

Thanks — Preceding unsigned comment added by Conestogo (talk • contribs) 17:07, 14 January 2011 (UTC)

Cocklestove

Hi, you seem to me to be misunderstanding what this word means - I must say I'd never heard it before, despite being very familiar with tiled stoves, and it isn't I think now in use in British Enmglish. This may be helpful, or this. It is certainly not a general English term for tiled stoves, especially domestic ones. I think the changes should be reversed. Johnbod (talk) 13:20, 24 April 2019 (UTC)

Physics of heat transfer

There are several references in this article to these heaters working by radiating into the living space. At 110°C and with shiny tiled surfaces I would expect much more convection than radiation. S C Cheese (talk) 20:00, 11 January 2024 (UTC)