Acremulating stoves save heating costs

Compact radiant storage stoves made of concrete are suitable for passive houses and timber constructions.

However, it often happens that the fireplace stoves in the household start to be used more and become a source of heating for a longer period than originally intended. This is precisely due to the unstable energy prices, as heating with wood remains economically more acceptable than other heating options. Moreover, the investment in correctly chosen fireplace stoves is still more affordable compared to investments in other heating devices.

That is why it is essential not to underestimate the selection of fireplace stoves to meet the requirements and expectations of the user.
 

How to properly choose a storage fireplace

It is really important to consider the heat loss of the building and select a heater that will comfortably heat the spaces, not overheat them.

The heat loss of a new building with a usable area of 120 m² at –12 °C is 5 to 6 kW. The heat loss of the living area (living room with dining area and kitchen) in such a house with a usable area of 40–50 m² at calculated frost temperatures (approximately –12 °C) is 2 to 3 kW. At temperatures around zero, it is a few kilowatts of heat loss per hour.

Storage fireplace stoves have the advantage of being freestanding units that can be installed practically anywhere in the building. It is necessary to consider the higher weight of storage stoves, which is around 400 kg. However, the vast majority of construction structures and floors have no problem supporting such a weight, so the limitations for stove installation are not significant.

Important factors when selecting stoves are the heater's performance, size, and, last but not least, appearance. Nowadays, the availability and time-consuming nature of assembly and installation are also important, considering the workload and time capacities of stove masons.

Storage radiant stoves heat for 12 hours on one loading

When choosing storage fireplace stoves, it is important to ensure that the stove has what is known as an active storage mass. This means that the engine of the stove is the storage mass, which is in direct contact with the flue gases. The flue gases during combustion flow directly around the storage mass, which accumulates heat.

Storage fireplace stoves with an active storage mass are designed for two to three fuel loads. The loading interval for storage stoves is 10 to 12 hours. Depending on the heat loss of the space and the desired comfort temperature of the user, the loading interval can be shortened. The shortest possible loading interval for accumulation is 8 hours between individual fuel loads.

Way of loading fuel and heat release

The fuel dose and time interval are determined by the manufacturer. If fuel is loaded more frequently than specified by the manufacturer, the efficiency of the stove decreases, and heat literally escapes through the chimney. At the same time, the stove and chimney are unnecessarily thermally overloaded, creating a risk of damage.

Utilizable energy from 1 kg of wood = 1 regular log approximately 33 cm long and about 10–12 cm in diameter = 4 kWh With the recommended fuel dose of 3 kg of wood, the obtained energy is 12 kW. At an efficiency of over 80%, more than 9.6 kW of energy is stored in the stove. This energy is then radiated from the surface of the stove into the living space, and due to the absorption of this energy over time, we obtain the stove's output measured in kilowatts per hour.

Storage fireplace stoves with an active storage mass formed by double-walled storage rings.

How to correctly heat with storage fireplace stoves

As mentioned, for optimal and continuous operation, storage stoves are designed for a loading interval of approximately 12 hours.

After loading the first batch of fuel and starting the fire, let the stove burn for about an hour, then load the second batch of fuel. During these two hours when the stove is burning, the stove "charges," accumulating the energy created into the storage mass. Subsequently, for the next 10 hours, the accumulated heat is gradually radiated into the living space through the surface of the stove.

So if you start a fire in the morning and evening, the stove will be in continuous operation, meaning it will remain warm and provide heat. This way, it is possible to continuously and smoothly heat the house with efficient fuel consumption and optimal stove operation.

Controlling the stove with electronics

For the proper functioning of storage stoves, it is essential to follow the correct heating procedure. After the combustion phase of the wood, approximately after two hours, it is necessary to close the air supply damper to prevent heat from escaping through the natural draft of the chimney.

For comfortable and easy operation, stoves can be equipped with electronic combustion control, which ensures electronic regulation of the air supply damper. Therefore, it is not necessary for the user to sit by the stove and wait for the fuel load to burn out. The electronic combustion control automatically closes the air supply damper after the fire goes out, and also optimizes and controls the air supply during combustion, regulating its amount and thus increasing the efficiency of the stove and optimizing the combustion process.

Radiant heat

One of the greatest advantages of storage radiant stoves is the transfer of thermal energy in the form of infrared radiation. Due to this radiation, there is no layering into thermal zones (the temperature near the floor and at the ceiling is very similar). The stoves heat objects, from which the surrounding air then warms up. It is a healthy, dust-free, and pleasant way of heating.

It is actually a kind of infrared radiation, similar to solar radiation. Radiant heat has a regenerative effect on a person because it can impact nerve endings at a depth of ~0.1 mm in the tissue. This thereby relaxes and soothes.
Heat accumulation in the stove's casing.

Heat accumulation in the stove's casing

1 hour after lighting Average surface temperature 29°C

3 hours after lighting Average surface temperature 88°C

12 hours after lighting Average surface temperature 45°C

Modular system of storage stoves for quick installation

Due to the energy crisis, the demand for wood heating has significantly increased in recent years, resulting in the workload and limits of stove masons.

Many manufacturers have reacted and started offering modular storage fireplace stoves made from individual prefabricated blocks. It's essentially a sort of sophisticated puzzle, while of course maintaining all the utility properties of the storage structure. For the stove masons, assembly and commissioning are less time-consuming and can be completed within a day.

Modular system of storage fireplace stoves facilitates installation and assembly.