REDISCOVERING WOOD

Already we saw above as the wood is a very cheap fuel , for those that have place to store it, and for those who live in areas where trimmings abound. We also saw some factors affecting its performance. This time we will see how this applies in stoves and fireplaces or wood pellets . (καυσοξυλα)

DIFFERENCE BETWEEN STOVE AND FIREPLACE

Both are composed of two parts: the home , where combustion takes place andthe chimney , through which the combustion products are discharged.Chimneys have a construction element, usually with refractories, while uncoated stoves are used, with the evacuation tube normally sight. (ξυλα για τζακι)

The stoves are made ​​of metal, steel or cast iron closed, and heat supplied in the same room in which they are placed .

The home fireplaces can be a simple hole with refractory material or carry a metal box with ventilation and pick-ash, also called cassette or insert. The cabinet may be open or closed. The evacuation tube is well hidden in a hood, either in a recessed wall, and can be used to distribute heat to other rooms discreetly.

THE OPEN WOOD FIREPLACE

Despite the charm of an open fireplace, where we can see the logs burn without any visual impairment, the performance is very poor . This is because the chimney draft is excessive: too cold air enters the combustion gases are discharged so quickly that not enough time to exchange heat with the room. In the best one is obtained in 20% yield .(καυσοξυλα)

It's very little, but hey! the wood is very cheap. The other day we calculated a price of 2 cents per kWh, and not even a good price, as some Nergizos's getting cheaper. Even with a yield of 20%, the final price only goes up to 10 cents per kWh, which is still cheaper than other sources. If we can think of using the open fireplace to burn pellets, then it would not be economical, since the fuel is 5 cents / kWh because of poor performance and the price would go up to 25 cents / kWh.

A medium fireplace burning wood holds a power of 14 kW, but poor performance, roughly equivalent to a 2.800W heater. Build a fire like this at home can cost around 700 euros, including the cabinet.  (ξυλα για τζακι)

WOOD BURNING FIREPLACE CLOSED CHAMBER

With something as simple as controlling the amount of air entering the combustion chamber A it is achieved dramatic performance increase , which easily reaches 60% . To stay longer hot gases within the chamber is achieved higher temperature, which contributes to better combustion, and allows time for heat is exchanged in the room. In the usual modern designs achieve a yield of 70%.

Aesthetically from the fire, you only see through a glass soot usually stained, or the door is metallic and directly see nothing is lost. In newer models, a secondary air inlet is used to avoid soot on the glass and give it some charm.

The price of the stoves depends greatly on the design because there are avant-garde and retro aesthetic, functional well. But as we are concerned over the energy cost savings, we consult prices more functional, and saw a stove without glass style umbrella stand with 8 kW peak power and 75% yield (effective power 6kW) leaves 430 € that the installation will be about 700-800 €. With this performance, the cost of burning wood here is of 2.70 cents per kWh. If we use pellets or briquettes instead of firewood in the stove, a competitive price of 6.70 cents per kWh it is still achieved, although some wasting the advantages of pellets, as we shall see.

An insert to put in a fireplace that we already had, it costs about 600 €, with glass door, 14 kW and 75% yield (10.50 kW of real power), adding that the price of the chimney at 1.300 €. It is more expensive, but we must also take into account the increased power required if it is very cold.