Stove lexicon

Only generated with firewood- systems and intervals with high power peaks. Use only with a buffer with a minimum of 500l.

Combustion chamber radiation and the energy of heating gases can be fed via boiler surfaces directly into the central heating. Indirect heated boiler surfaces are maintenance- free and do not have to be cleaned. Systems with heat transfer through air flowing heating gases need to be cleaned regularly.

Cast iron is one of the oldest materials for mechanically stable and durable components. Minimum elongation and machining. Very durable.

Fireclay plates in a memory block of an oven. These flue gas ducts can have a length of up to 10 meters and are fitted perfectly between the combustion chamber and the chimney. They are not easy to insert because it is of paramount importance to make sure the smoke does not get too cold or too warm in the chimney. Rules of thumb: per kg wood approx. 50-75 kg thermal mass. Storage furnaces with a filling room for 10 kg wood will be built with a storage mass of 500 to 700 kg.

No furnace "pulls", "pulls badly" or "pulls good". The heating gases rise in the combustion chamber, however it still needs a minimum negative pressure (draught) to transport it to the outside. The chimney cross- section is in a fixed ratio to the effective height. Exact measurements can be given by your local supplier. A minimum height of 4,5 meters must be considered. We recommend a minimum diameter of 160mm-180mm for all tiled stoves and fireplaces, and for open fireplaces it should be at least between 250mm and 350mm, because not only the amount of heating gas needs to be transported but also the room air, which is aspirated through the big vent.

This important natural underpressure, also called “chimney flue”, results out of the difference between outside temperature (chimney head) and the room temperature (start of the chimney). Due to the temperature difference in- and outside there is a thermic or a pressure difference (flow), which rises from the bottom to the top. In case of too big resistance between the combustion chamber and the start of the chimney the needed draught (or under pressure) cannot get through to the combustion chamber and smoke will enter the room. On the other hand there can also be overpressure instead of under pressure. This can happen on warm summer days when the chimney head gets heated up by the sun, and the stack muzzle is warmer as the entry in the room.
The thermic works vice versa. The only thing that can solve this problem would be to turn the procedure round by lighting a piece of paper, which is actually forbidden.

Tiled stove design between hot air furnace and storage furnace. A detached combustion chamber provides hot air just like a hot air furnace but the gases are sent to a memory block like with a tiled stove. Therefore it is possible to achieve long lasting warmth by only having a short time heating up. The combination of hot air/radiation can be transcribed individually to customer requirement.

1 kg of wood requires 4m³ combustion air. A good wood- fired oven take double as much excess air and 8 to 10 kg wood. For excellent efficiency and low emissions the exact setting is significant. The combustion air has to be closed after burn-off.

The combustion chamber is the most loaded component. It must be well thought- out due to temperatures of over 1000 degrees. A significant part of the energy and warmth released by the combustion chamber (up to 50%) is emitted by the combustion chamber. It is advisable to fire up to an inflammable temperature of over 600 degrees quickly.

Ember is the carbon structure what is left over after all the chemical compounds have dissolved.

New houses are usually low- energy-buildings, which cannot obtain the needed combustion air from the indoor air. Easily over 100 m³ are dissipated in less than an hour. Climate and ventilation devices can also disturb the operation of a wood fired oven. In this case combustion air will be led to the combustion chamber directly by using an air duct.

This is the coordinated amount for a combustion stove and the appropriate system. A minor (or also a greater) filling quantity would have a negative impact on efficiency and burn- off quality.

Fireproof material for combustion chamber and thermal mass, which is highly resistant. Available for different types of density and heat resistance.

Usually set into ceramic glass and, such as an open fireplace, connected to the chimney. With this solution the amount of needed air and the chimney cross- section are decreased to an average level.
The heating effect is provided by the radiation of the glass window and the combustion chamber, which emits warm air.

By this, we mean energy supplies which were originated from biomass millions of years ago. As we all know these sources will not last forever and will surely become more expensive in the future.

Constructed to supply the right combustion air- flow to the needed combustion level. This will guarantee a clean and comfortable use of a wood stove.

A highly heat- resistant transparent ceramic, which allows a perfect view into the combustion chamber and onto the open fire. With its high surface temperature (up to 400 degrees) it gives out heat through high radiant power. It is important to align this thoughtfully.

A size measure for ovens and stoves stated in kW. It only tells you that the heat generator can generate. This indicator refers to power declared to the specific device over a period of 1,5 hours. Therefore it is important to contemplate the design for they can be very different to handle. A storage furnace will need 20 kg wood, burns for approx. 24 hours and provides a thermal output of 3kW. A fireplace or a hot air furnace however has to be fired every 2 hours. This would add up to about 20 to 22 kg wood a day for the same output.

Heat output is therefore influenced by the amount of fuel. 1 kg wood has a heating output of 4kWh/kg. 10 kg wood provides 40 kWh as a heating output. By using intervals it is possible to regulate the desired output. Heat emission systems influence the effect that can be realised (fast system= fast and high output, slow system=low power output).

The heating value is in charge of how much heat quantity (in kWh) is supposed to be achieved. Here there is no difference to be found between different woods. Softwoods state at 4,4- 4,5 kWh/kg and hardwood at 4,1- 4,2 kWh/kg. Normally firewood is bought in cubic meters. One m³ of softwood weighs approx. 360 kg and m³ of hardwood approx. 510 kg. Referring to heating value this would be 1600 kWh/m³ for softwood and 2100kWh/m³.

Another important aspect is the wood humidity. Please see the table for water content below.

Estimated it can be said that freshly cut wood only achieves half of the heating output compared to the stored wood. In concrete terms this means that for a heat requirement of an average of 4kW an amount of 4kW x 24 hours= 96 kWh/day is needed. By using hardwood for covering the needs it will last for at least 3 weeks. 2100 kWh a day= 21 days and 21 hours, in comparison freshly cut wood only last for 11 days.

Size measure is stated in kW and tells you how much energy is required per hour. A heat requirement (for a room/house) of 3 kW would mean that 3kWh are needed every hour to achieve the desired heating effect. For 24 hours: 24x3=72 kWh. This corresponds to a heating value of 20kg dry firewood on an oven with an efficiency of 85%.

Generated when cooler air warms itself up on hot surfaces like with furnaces, fireplaces and tiled stoves. The hot air- principle warms up the air through a “circulatory system”. This enables to heat up large rooms. Dry air and dust can make you feel uncomfortable and there is a great danger of “overheating” a room. Ovens with too hot surfaces can evoke dust- carbonising.

Tiled stove design where released energy is implemented into heat output immediately. A cast iron heating insert with a metallic reheating surface alongside in the oven case, which warms up the room air and exits as earm air through grids.

These are “cooling surfaces” where heating gases pass the combustion chamber and cool off on the way giving warmth. In order to achieve the best possible result it is advisable to check which filling quality your construction requires.

Usually an open fireplace is a handmade, stonewalled fireplace which is connected directly to the chimney in order to heat a room. Usually dry hard woods are preferred because the combustion is hardly sparking due to the cell structure of these woods. Please note that a minimum of 300m³ combustion air referring to one m² firebox is needed to set such a system up.

When the filling quality and the combustion air are geared to the combustion chamber, and mixing of the heating gases to a minimum of 600 degrees is guaranteed.

Wood pellets consist of untreated wood leftovers (sawdust). Only use wood pellets according to DINplus or Ö-norm M135 with following characteristics:

Wood pellets are not allowed to contain impurities or inorganic binder. This natural product is a by-product of sawmills and can be purchased via organised fuel trade. It is not allowed to use different materials or else no warranty can be given.

(as of 10/2005)

Tiled stove fireplace surfaces can also be set up with plastered fireclays. Please note that these systems have to be cleaned and repainted regularly due to traces of smoke and dust. Special plasters are available in many different grains and structures. It is important in any case that the body of the stove is free to make sure no cracks appear when heating up.

Heat rays, also known as infrared rays. The radiation does not heat up the air but the “body” it meets. This can be anything- furniture, plants, animals or human beings. Can be compared to the heat radiation of the sun. However it is generally perceived as enjoyable. A surface temperature between 40 and 65 degrees is the most pleasing. Heat rays from the combustion chamber are too hot, even when a glass window is inserted, and should not be pointed at human beings. Storage furnaces/ basic furnaces and tiled stoves are known as radiant heating solutions, which are able to provide mild radiation heat for several hours.

Solar energy and biomass are renewable energies. Wood is a renewable energy source. Firewood is mostly regional wood breakage.

Systems with efficiency need a combustion chamber which is equipped with surfaces to use the energy contained in the heating gas. Ovens with smaller reheating surfaces blow too hot exhaust gas temperature in the chimney. By using certain reheating surfaces the level of thermal effect can be determined. Boiler surfaces for production of heating water, metallic surfaces for hot air and ceramic reheating surfaces with delayed delivery of radiation heat.

A community of master craftsmen who have devoted themselves to the values of traditional and handicraft furnace- construction.

A natural stone with a very high gross density, which is therefore very often used as thermal mass and also covers the fireplace. Unfortunately only available in grey.

Neither newspapers nor waste paper should be used. Only use split wood or natural starting aids like “fidibus”. Here is the rule: fire quickly!

A start-up flap is a short- circuit flap for flue gases. Suitable reheating surfaces, especially for ceramic features are welcome to provide best efficiency. Due to bad weather conditions the chimney may not be strong enough to pull the flue gases all the way from the combustion chamber. The furnace will smoke. Therefore there is a “short cut” which can be switched on- or off through the start- up flap. As soon as the furnace is set it will be closed again and the gases can extract as usual. Start-up flaps are available for manual or automatic use.

Is usually a fireplace, which is closed by ceramic glass and does not immediately transport the heating gases from the combustion chamber into the chimney, but heats up a ceramic thermal mass. This is the solution with the most efficiency- even though the fireplace is off radiation can still be felt for hours.

Tiled stove design that slowly releases the heat from the combustion chamber to the room. The gases flow from the ducts of the heating block, which is charged like a “heating battery”, to then set the energy free by releasing it through the surface as mild radiant heat. The heat output is determined by your stove engineer. the storage capacity depends on the weight.

It is the shell of a tiled stove, the architecture of the system. These are not regular tiles, they are made of ceramic mass, which steer the flow of heat evenly.

Stores not needed energy output, and sets it free when required. A ceramic draught system is inserted as thermal mass into the tiled stove, which defers heat, depending on the design, and emits it to the installation room (see ceramic draught system). For boiler devices an extra buffer will be fitted, which is normal for heating installations and works the same way. Excessive generated heating water will be stored temporarily and transported to the different rooms by the heating system when needed. To warm up 100l of water up to 10 degrees, 1,16kWh of water is needed. To heat up an amount of 750l from 30 to 80 degrees a heat quantity of 43,4 is required. This corresponds to the energy content of about 11 kg of wood.

It is always a closed fireplace, which makes use of hot flue gases in a best possible way. All functions and individual heat emission systems are possible. Only offered by specialists. Surfaces usually made of glassed ceramic tiles. This is why it is calles a tiled stove. Known as the top level of stove- design and is available with a viewing glass.

Wood is an organic material, a natural composite of cellulose fibres, which is the result of photosynthesis and therefore is a regenerative energy resource.

Wood pellets consist of untreated wood leftovers (sawdust). Only use wood pellets according to DINplus or Ö-norm M135 with following characteristics:

Wood pellets are not allowed to contain impurities or inorganic binder. This natural product is a by-product of sawmills and can be purchased via organised fuel trade. It is not allowed to use different materials or else no warranty can be given.

(as of 10/2005)