Accumulation fireplace

BEAUTIFUL VIEW INTO THE FLAMES COMBINED WITH MODERN ENERGY STORAGE AND UTILIZATION TECHNOLOGY

Storage fireplaces are designed for all fire enthusiasts. They often come equipped with large glass doors, offering a stunning view of the flames in the fireplace. With this comfort, however, they are capable, thanks to their design and materials used, of distributing the generated thermal energy over a longer time interval. This reduces the current hourly thermal energy output and prevents unnecessary overheating of the interior.

Storage fireplaces, like storage stoves, have a huge advantage in the way they transfer thermal energy to their surroundings. Unlike, for example, warm air fireplaces, which only heat the air, storage fireplaces utilize so-called radiant heat. Radiant heat does not heat the air but rather warms individuals and objects the moment it "hits" them. Radiant heat has the same wavelength as sunlight; it is infrared radiation that can only be emitted by the sun and fire. It provides users with thermal comfort and a healthy heating method. Radiant heat has a restorative effect on the human body, as it can affect nerve endings at a depth of approximately 0.1 mm in the tissue, promoting relaxation and calmness.

THANKS TO ITS DESIGN, THE FIREPLACE ACCUMULATES A LARGE PART OF THE GENERATED THERMAL ENERGY

The storage fireplace is used by adding fuel approximately 2 to 3 hours after the initial lighting (a total of two or three fuel batches). This ensures that the user has a view of the flames for several hours.

Thanks to its design, the fireplace accumulates a large portion of the generated thermal energy. This energy is absorbed by the fireplace's walls many hours after the fire has gone out (through so-called radiant walls). Most storage fireplaces are designed for a time interval of 8 to 10 hours.

Energy Output of the Storage Fireplace

Thanks to modern family home construction, most heated structures today have a thermal loss of under 10 kW. Thermal loss refers to how much heat a structure loses through ventilation and the transfer of heat through building materials in one hour. Simply put, the same amount of heat must be brought into the structure every hour to maintain the desired temperature in the house.
However, it is important to consider the fact that thermal loss is determined for temperature extremes from -18 °C to -10 °C (depending on the area and altitude). Most often, outdoor temperatures during heating days are around 2 °C to 4 °C. For this temperature, the thermal loss of the structure is approximately half. When we also consider that we usually only locally heat part of the house with the fireplace, the actual losses that need to be compensated by the fireplace are only a few kilowatts per hour. This is precisely why storage fireplaces are replacing previously used warm-air fireplaces, which unhealthily and unpleasantly overheat modern interiors. They are an affordable alternative that also looks similar. They simply provide users with thermal comfort and a healthy heating method.

The Shell of the Storage Fireplace

A storage fireplace is a so-called radiant structure. This means it transfers thermal energy through radiation from the heat exchange surfaces of the fireplace. The heat exchange surface (fireplace shell) is made from materials that ensure smooth heat absorption, having good thermal conductivity. In the fireplace chamber, heat accumulates first during combustion, radiating from the metal body of the fireplace insert, and later radiating from the storage flue system. This accumulated heat passes through the shell of the fireplace and is transferred to the space through perpendicular radiation from the surface (heat exchange surfaces).

SPATIAL EFFICIENCY, WIDE VARIETY OF DESIGNS

Like storage stoves, storage fireplaces can be equipped with various doors. Again, the smaller the doors chosen, the smaller the portion of direct radiant heat from the flames. For buildings with lower energy loss, it is thus advisable to use smaller doors, and vice versa.

The storage fireplace does not require much space. The dimensions of storage fireplaces are similar, and often identical, to those of previously popular and frequently used warm-air fireplaces. The differences between these fireplaces lie in their construction and method of use.

The Inner Core of the Storage Fireplace

The inner core of the storage fireplace is the fireplace insert connected to the so-called storage flue system. The fireplace insert must be designed by the manufacturer for installation into a closed casing of the storage fireplace. It is not cooled by flowing air as, for example, a fireplace insert placed in a warm-air fireplace is. This makes it temperature-stressed much more and it must be designed to withstand such stress.

The flue outlet from the fireplace insert is connected to the storage fireplace's storage flue system. Its exact positioning, length, cross-section, and thickness of materials must be professionally dimensioned specifically for the particular chimney, used fireplace insert, and altitude. For this dimensioning, we utilize both traditional calculation methods and modern software used throughout Europe.

The amount of fuel (wood) added to the fireplace insert creates the right temperature needed to heat the storage flue system. The storage system gets "charged" with thermal energy, which it continues to absorb gradually even long after the fire has gone out in the fireplace insert.

Regulation of the Storage Fireplace

Combustion in the storage fireplace is regulated by adjusting the supply of combustion air. The air can be regulated in two ways. The first option is manual combustion regulation, which is a part of every fireplace insert. The second option is the use of electronic combustion regulation. This, based on a temperature sensor, allows just the right amount of air for combustion to flow in, as needed by the fireplace. A significant added value of combustion regulation is that after the fire goes out, it completely closes the air damper, thus stopping the airflow through the fireplace insert and the storage reservoir. If air were to flow through the system, it would act as a "cooler," removing thermal energy to the chimney.

Another advantage of electronic combustion regulation is the ability to regulate draft through the chimney using a chimney damper. This is regulated based on temperature in the chimney, ensuring that unnecessary large amounts of unused energy do not escape through the chimney. This essentially optimizes the efficiency of the fireplace to the maximum and simultaneously protects the chimney from damage due to excessively high flue gas temperatures.