Radiant heating - function, types and possible applications

But how do radiant heaters actually work? And what types are there? Read all about radiant heating systems and why they are the ideal choice for industrial and event halls in our article.

Radiant heaters - the difference between light and dark radiators

Heating systems, as we know them from our private homes, work with water that is heated at a central location, flows through the radiator, and thus heats the room. Radiant heaters, on the other hand, do not require a transfer medium such as water that is heated centrally, but generate heating energy directly in or on a radiant component that projects the heat into the environment. There are now three different types of radiant heaters: light radiators, dark radiators, and the new Fair.AIdH*technology. All three variants are similar, but function differently.

Characteristics of high bay heaters

In radiant heaters, which are bright radiators, a fuel gas mixed with the combustion air burns on a high-temperature-resistant, perforated ceramic plate. The burner surface heats up to temperatures between 750 °C and 950 °C in the process. The plate of the radiant heater glows visibly, which gives the heater its name, and emits infrared radiation into the environment. As soon as the radiation hits solid bodies, it is converted into heat. The exhaust gases produced by this open combustion are usually released into the open air with the room air. It is therefore important to ensure adequate ventilation, for example with ceiling fans.

Characteristics of dark radiators

The second type of radiant heaters are so-called Dark radiator, which today are usually called infrared radiators. They are also among the decentralized hall heating systems that combine heat generation and heat transfer in one device. Although their physical principle is identical to that of bright radiators, they have a different mode of operation. Dark radiators do not work with open combustion, but with pipes, usually in a U-shape. A combustion gas, usually natural gas, flows through these tubes at a temperature of up to 800 °C - a suction fan at the end of the tube generates the negative pressure for transporting the combustion gas, which is burned by a burner. The average surface temperature of 250 °C to 500 °C is approximately the same along the entire length of the pipe. Finally, a reflector directs the infrared radiation from the pipes into the heating area so that the heat generated by the radiant heating is transferred to the surroundings.

Why the name dark radiator is outdated from a technical point of view

In contrast to bright radiators, the term dark radiators used to refer to a non-glowing heating surface in radiant heaters. Today, however, there are also devices with glowing tubes in the high-performance class of dark radiators. So why are they not classed as bright radiant heaters? Because they work with closed rather than open combustion. The name infrared radiator therefore seems more appropriate for this type of radiant heater. The great advantage of closed combustion is that users can discharge exhaust gases in a controlled manner via pipes. And, if desired, the residual heat can be transferred to a heat exchanger to heat offices, for example, via a classic hydraulic heating system.

Characteristics of Fair.AIdH systems

The third and most recent type of radiant heating—also known as multi-energy IR heating—was developed for the transition to a carbon-free era. This technology is similar in function to dark radiator technology, but sets new standards in two respects: Firstly, these solutions can be used as a 2-in-1 system to simultaneously provide LED lighting for halls, which almost halves the costs for cabling and control, as well as for service calls. Secondly, Fair.AIdH systems are energy-flexible and can be operated with PV or mains power, hydrogen, biogenic gases, and even natural gas. If renewable energy is unavailable or too expensive, for example due to dark doldrums, another energy source is automatically used, thus ensuring operational reliability during the cold season. This achieves the high efficiency levels of the most modern dark radiators, which can compensate for rising energy prices and makes the decarbonization process economically feasible for companies.

By the way, if you're interested: The abbreviation Fair.AIdH* means „energy" Flexible, adaptive, infrared, AI driven Hall Heating“ and stands for the new energy-flexible heating technology for decarbonizing industrial buildings.

A brief digression: It could also be electricity

Electric radiators are a special type of radiant heating system. They do not rely on the combustion of fuel, but rather on the flow of electricity through an electrical resistor. However, electric radiators did not play a role in heating industrial buildings for a long time – they were more commonly used for baby changing tables or for heating benches and tables in beer gardens. The reasons for this were simple: apart from the fact that the grids are not designed for such large consumers, mains electricity was simply too expensive for the large quantities required for heating halls. This is still the case today, but many companies are now installing PV systems. Experience has shown that these can also generate good yields in winter, making the use of electric radiant heaters increasingly attractive in industrial and commercial enterprises. This is especially true when a reliable heat supply is needed in the absence of PV power with energy-flexible Fair.AIdH*technology can be ensured by other energies such as natural gas or hydrogen (blend). An exciting approach, which is being implemented by one of the first companies at the Trier-based metal processing specialist. „Kanter & Schlosser“ was used.

This is where radiant ceiling panels differ from other radiant heating systems

Radiant ceiling panels also work with thermal radiation - heating elements in the form of profiled strips made of sheet steel with welded-in pipes. Hot water flows through the pipes, heating the radiant surfaces so that they emit radiant heat. Radiant ceiling panels can also heat large halls. Due to their low temperature, radiant ceiling panels require very large areas on the ceilings and therefore a relatively large amount of space. In addition, hot water as an activator is a very inert medium. Temperature changes and adjustments of the heating operation to a dynamic daily routine can therefore not be realized as quickly as with gas-powered radiant heating systems.

Radiant heating - the optimal choice for industrial halls

Halls with ceiling heights of several meters have a gigantic volume, and only a small portion of around 20 percent is usable space—usually 2.5 meters above the floor. The problem: with conventional convection, i.e., warm air, it is difficult to heat this area in a targeted and efficient manner. This is because warm air does not stay in one place but always rises to the top—where no one needs it. This is an unavoidable physical principle that causes hall operators to suffer significant heat loss. In addition, warm air currents cause dust to swirl and create unpleasant drafts in halls. With radiant heaters such as light or dark radiators, this does not happen and targeted heat emission is ensured.

Aspects that speak for decentralized radiant heating systems

As already mentioned, radiant heating enables the targeted heating of the desired area of a hall. It is therefore pleasantly warm where people are working, while it remains cool in the upper layers of air. Even when gates and doors open and close frequently. Radiant heating systems are therefore not only absolutely efficient, but also save a great deal of energy.

The heat from radiant heating systems is also immediately available, as there is no need for a reaction-carrying detour via heat-conducting media such as water and air. This means that rooms that normally remain cold can also be heated efficiently for short periods of use. For example, storage rooms that employees rarely enter. As there are no draughts when heating with radiant heating, dust pollution is also reduced. This makes infrared systems ideal for allergy sufferers and a generally more pleasant and healthier indoor atmosphere.

Save up to 70 percent energy with radiant heating

However, radiant heating systems not only make it possible to heat cold rooms quickly and for a short time, they also allow operators to divide huge hall spaces into several heating zones. This means that they do not have to set a standard temperature, but can, for example, set different temperatures near the Waste heat of machines and systems, but more in the storage area. In this way, radiant heating provides all employees with the perfect feel-good temperature - without wasting any energy.

If users also connect the radiant heaters to smart controls and energy management systems, they can continuously monitor and optimize all heating parameters. The bottom line is enormous cost savings. Compared to conventional convection systems, hall operators using these radiant heaters typically save between 40 and 50 percent, and in some projects even more than 70 percent, in energy costs.

A small example: St. Pauli fish auction hall saves around 50 percent on energy costs with radiant heating

However, radiant heating systems are not only used in industrial halls. Word of their advantages has long since spread in the event industry. You can find the Heating systems now also at concerts, art exhibitions and Company eventswhich take place in unusual locations - such as old fish factories or heating plants.

For example, in the old fish auction hall on the St. Pauli fish market. For many years, KÜBLER radiant heaters have been providing pleasant warmth on stage, at tables, benches, and food stands in the 103-meter-long and 23-meter-wide hall, which is eleven meters high at the dome. The cubic meters of air above the usable area, on the other hand, remain cool. Without bothering anyone. On the contrary: the operators save up to 50 percent in energy costs compared to conventional hot-air heating systems.