Golden Fire burns wood cleanly and efficiently

NunnaUuni’s patented Golden Fire wood burning method (Pat. no. EP1008808) produces an extremely high temperature, in which wood gasifies evenly and burns efficiently. As a result, NunnaUuni fireplaces produce only minimal wood-burning emissions. Genuine NunnaUuni fireplaces, tested in accordance with heat storing fireplace test method, are built to adhere the emission limits of the future EU EcoDesign standards. In this strictest test method only for heat storing fireplaces the smoke gases are measured during the entire burning phase, starting from the moment the fire is lit.

European Standards for measuring the emissions of space heaters

Harmonised European standards categorise biomass room heating appliances based on various technologies. This generally includes room heaters (wood burning stoves), insets or slow heat release fireplaces.

The official test methods for room heaters (EN 13240) and insets appliances (EN 13229) only measure emissions at nominal load and after the operating temperature has been reached. The ignition of the first batch of wood and the heating-up of the stove are not factored in to the emission results.

In the European test method for slow heat release fireplaces (EN 15250), emissions are measured upon ignition and heating-up of the fireplace in accordance with manufacturer instructions regarding the complete combustion of the amount of wood specified. All exhaust emissions during the burning are included in the test results.

Wood placed on the NunnaUuni’s Golden Fire grate is lighted from underneath. This ensures that all logs begin to burn quickly. The burning process is efficient and clean from the very start.

If wood placed in the burning chamber is lit from the top, the resulting slow burning process will produce humid flue gases which will form a layer of pitch coal inside smoke ducts and flues. When this layer dries, it forms an uneven, blistery surface, which can easily cause a soot fire.

The Golden Fire gasification burning method, EP1008808.

The Golden Fire burning method developed and patented by NunnaUuni is based on the precise direction of air, which ensures that exactly the right amount of air is used in the different phases of burning. This is possible, because the grate we use in our fireplaces is specially constructed with holes and equipped with a controller that ensures that the amount of oxygen remains exactly right during the different phases of heating, from lighting the fire down to the embers.

  1. Combustion air is conducted into the space under the Golden Fire grate, either from the surrounding room or straight from outside the house. When conducted in from under the grate, the air cools the grate down and simultaneously preheats.
  2. A small portion of the combustion air is conducted under the embers through holes found in the Golden Fire grate to ensure that the gasification burning process continues smoothly and evenly. (This is a key difference to fireplaces which employ a traditional fire grate, as in them, all of the combustion air is conducted under the burning logs. This results in a fire that burns in an unstable and uncontrollable way.)
  3. Most of the preheated combustion air is conducted from the sides of the Golden Fire grate to the space around and above the logs where it serves as secondary air and ensures that the gases released evenly from the said logs burn at a high temperature of 800–1 200°C.