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 environment work with water, which is heated at a central point, flows through the radiator and thus heats the room. Radiant heating systems, on the other hand, do not require a transfer medium such as water, which is heated centrally, but instead generate heating energy directly in or on a radiating component, which projects the heat into the surroundings. There are two different types of radiant heaters: Bright radiators and dark radiators. Both variants are similar, but have a different mode of operation.

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.

A brief digression: it doesn't always have to be natural gas

Electric radiant heaters are a special form of radiant heating. They do not rely on the combustion of a fuel, but on a current flow in an electrical resistor. However, electric radiant heaters do not generally play a role in the heating of indoor buildings - they are more suitable for baby changing tables or the heating of benches and tables in beer gardens. Nevertheless, this is an exciting approach that will be further developed and expanded over the next few years to offer alternatives to radiant heating systems, such as dark and light radiators, as well as classic heating systems.

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 part of around 20 percent is the usable area - usually 2.5 meters above the floor. The problem: with classic convection, 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 upwards - to where nobody needs it. A physical principle that is incorruptible and causes hall operators a great deal of heat loss. In addition, warm air currents cause dust turbulence and unpleasant draughts in halls. With radiant heaters such as light or dark radiant heaters, this does not occur and targeted heat dissipation 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 network the radiant heaters with intelligent control systems and analysis software, they can continuously monitor and optimize all heating operation parameters. The bottom line is enormous cost savings. Compared to conventional convection systems, hall operators generally save between 30 and 50 percent energy with these radiant heating systems, and up to 70 percent depending on the project.

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. Radiant heating systems from KÜBLER provide pleasant warmth on the stage as well as at tables, benches and food stands in the 103-metre-long and 23-metre-wide hall, which is eleven meters high at the dome. The cubic meters of air above the usage area, on the other hand, remain cool. Without disturbing anyone. On the contrary: the operators save up to 50 percent in energy costs compared to conventional warm air heating systems.

Six mistakes you should avoid when planning heating systems for new hall construction

Now more than ever, hall heating has an impact on a company's profitability and freedom of action. Why? Because energy prices are rising and environmental regulations are becoming stricter. But which heating solution is the most energy-efficient and future-proof? Companies don't have much room for experimentation. Once installed, heating systems usually remain in operation for up to 20 years. This makes it all the more important to invest a lot of time in heating planning before investing. A phase in which you should avoid the following mistakes.

Mistake no. 1: Only superficially studying the relevant laws for new hall construction

Laws are generally complex. A superficial study can become a pitfall here. This also applies to the new Building Energy Act (GEG), which has been in force since November 2020. Although it simplifies and summarizes the previous legislation - namely the Energy Saving Act (EnEG), the Energy Saving Ordinance (EnEV) and the Renewable Energies Act (EEWärmeG) - it often confuses companies. For example, many managers assume that they can only use renewable energy when building new halls. This is a fallacy that restricts the choice of technology. And often leads to compromises that are demonstrably too expensive - both to purchase and to operate. A closer look reveals this: Hall operators do not have to use renewable energies for decentrally heated zones with ceiling heights of over four meters. They can also use gas-powered infrared heaters, provided their efficiency and energy efficiency are high enough.

Mistake no. 2: Treating a hall like an office building

Offices are generally well-insulated rooms with low ceilings. Their volume is almost identical to the usable zone. It is therefore not a waste of energy to heat the entire room. However, the situation is completely different in industrial and commercial buildings. Anyone using the heating approach for multi-storey buildings is wasting heat and money. This is because it is usually sufficient for the working area to be warm. As a rule, this means the lower two meters of the hall - in the case of a hall with a ceiling height of ten meters, only 20 percent of the room volume. Or even just the part where people are working.

With such a targeted heating approach, the following principle applies: the smaller the ratio between the usable area and the total volume, the more important the quality of the heat transfer. Infrared heaters achieve a high level of quality here. Instead of heating the air per se, the decentralized heaters generate electromagnetic waves that are only converted into heat as soon as they come into contact with solid objects. In combination with intelligent control systems, energy savings of up to 70 percent can be achieved compared to conventional heating systems. This is a significant factor, as it can be assumed that energy will become more expensive in the coming years.

Error no. 3: Usage profile and requirements are not specified

Simply install a heating system and switch it on until it is halfway warm everywhere? Companies have been wasting energy in this way for decades. A waste that can become a competitive disadvantage in times of rising energy prices. Therefore, consider in advance what makes your new building stand out: Where exactly in the hall do employees need heat, where can it stay cooler? How much air exchange takes place in the hall and when? How much waste heat do machines and systems already produce? How can this be used intelligently?

If you know these parameters, specify requirements and create a detailed usage profile, a responsive heating system with intelligent control can adapt to the hall like a tailor-made suit. And save a lot of energy. Because the most economical heating system in terms of consumption is the one that the operator doesn't even have to switch on.

Mistake no. 4: Not using networking and intelligent control when building a new hall

Intelligent control is a luxury? Networking a superfluous gimmick? No, digitalization is essential in order to heat halls in an energy-efficient way and save a lot of money in the future. It is therefore essential to make sure that the heating system for your new building has arrived in the digital age. Networked devices, modern control systems and analysis software make it possible to adapt heating systems to the hall dynamics and thus save energy. In addition, hall operators can better meet the requirements of the DIN 50001 standard with software-supported heating systems. With this certification (or a registered environmental management system acc. EMAS Regulation), you meet the requirements for partial exemption from the EEG levy or future relief from electricity and energy tax.

Mistake no. 5: Only looking at investment costs

Focusing only on initial investment costs for decision-making? That can also be a mistake. Because much more important are the total costs that are incurred over the entire life cycle of the heating system - including service, maintenance and repair costs. A particularly interesting part of this total cost of ownership (TCO) is the consumption costs. Here you should never let the provider get away with a pi times the thumb estimate. Nowadays, it is easy to provide detailed and reliable information in accordance with DIN V 18599 - including the annual primary energy requirement, energy costs and CO₂-emissions. Information that gives you planning and decision-making security.

Mistake no. 6: Not taking a close look at providers

On the way to an economical heating system for your new hall construction, you should not only take a close look at the quality of the devices, but also at the competence of the manufacturer. Research whether the company can provide credible references. Equally important: To avoid long downtimes, you should make absolutely sure that the provider will still be offering services and a spare parts supply in fifteen years' time. After all, it is annoying if you are left to your own devices to maintain your hall heating system after just a few years. You can also find out whether the company has its own research and development department. Such a department - especially in combination with convincing references - is usually a reliable indicator of competence and experience. Two points that are important for finding and operating an economical and future-proof hall heating system.

Hall heaters - solutions for event halls and exhibition rooms

Concerts, art exhibitions and corporate events are increasingly taking place in unusual locations - for example in old fish factories, heating plants or in tents on historic factory sites. The ambience is often a mixture of rustic and modern. An atmosphere that only unfolds, however, when the temperature is right. After all, who likes to drink Chardonnay with cold feet? Or eat a salmon canapé with a chilled nose?

That's right, nobody. And that's why most event organizers strive to maintain a comfortable temperature. They experiment with various heating solutions. For example, with mobile warm air heaters that blow heated air into tents via warm air hoses. Or with mushroom heaters, near which guests warm themselves with a gas flame.

The problem: many hosts are not really satisfied with warm air systems as hall heaters

Because warm air has a mind of its own. It is distributed unevenly in halls and tents, mixes with cold layers of air and creates a draught on guests' legs, arms and necks. "Darling, do you think we should leave so slowly?" is a sentence that is uttered far too early in the evening at worst. Not the only drawback.

The electricity bill is also often unnecessarily high. This is because warm air escapes towards the ceiling - i.e. to where it does no one any good and only causes energy costs. Creating different temperature zones, such as a cool zone at the buffet and a warmer one in the common areas? Virtually impossible with air that is constantly mixing. Last but not least, many warm air systems do not look very stylish as hall heaters, more like relics from the 1980s. They often cannot be integrated into a modern environment without a visual break. And in the worst case, they are so loud with their humming and hissing that they disturb the ambience.

Targeted and economical heating: infrared heaters reshuffle the cards

For hosts who are not satisfied with warm air systems because they are too loud and unattractive, consume too much energy and do not even satisfy many guests, there is an alternative solution: Infrared heaters. These hall heaters are reshuffling the cards when it comes to heating event halls and exhibition spaces. Why?

Because their functional principle differs fundamentally from that of warm air systems. Infrared systems do not heat the air. Instead, they generate electromagnetic waves that are converted into heat as soon as they hit solid objects - such as guests or tables, benches and stages. The advantage: hosts no longer have to heat the entire air in a hall or a large tent to create a pleasant temperature, but can concentrate specifically on the area of use. As this is usually many times smaller, you save a lot of energy. But that's not all.

Bringing the pleasure of pleasant sunlight indoors

Do you know this? You go for a walk on a fall day. The air is pleasantly cool, but at the same time you can feel the warm rays of the sun on your skin. A feel-good atmosphere that infrared heaters also create indoors. Guests find the infrared heat particularly pleasant because it corresponds to the natural heating principle of the sun - without dry heating air, dust turbulence and draughts.

The eye is not neglected either. Modern infrared heaters can be discreetly integrated into the surroundings or emphasized as a design element in their own right. In addition, the hall heaters are whisper-quiet and would not even disturb Ludwig von Beethoven's 15th string quartet. They are therefore perfect for controlling the temperature of large marquees, event halls and exhibition rooms.

Hamburg fish auction hall pampers guests with infrared heat

Do you know the fish auction hall at the St. Pauli fish market? It is a magnet for night owls and tourists from all over the world. This is because visitors come here every Sunday from dawn to buy fish sandwiches and other delicacies from hundreds of food stalls and food trucks. They enjoy eating and drinking in a cheerful get-together on beer benches in the fish hall - with live music until twelve o'clock at night. An inviting backdrop that is also appreciated by organizers of cinema festivals, theater and reading days and the multi-day light festival. Events with up to 4,200 people regularly take place in the 4,100 m2 hall.

And the temperature in the fish auction hall is always just right. This is because the operators have installed infrared radiant heaters from the OPTIMA painted to match the style of the architecture and suspended from specially designed, invisible wire ropes. The devices heat the 103 meter long and 23 meter wide hall, which is eleven meters high at the dome, with a total output of 700 kW. The heat from the hall heaters is concentrated specifically on the area of use, i.e. the tables, benches, food stands and, of course, the guests themselves.

The thousands of cubic meters of air above this area, on the other hand, are cool without disturbing anyone. Visitors' ears are also spared any annoying noise. KÜBLER supplied the radiant heaters in a super-silent design and also soundproofed the exhaust fans. This reduces the noise effect from industry standard to almost concert level.

Fish auction hall saves 50,000 euros in heating costs per year

However, the operators of the fish auction hall not only benefit from the modern, unobtrusive appearance and quiet operation of the hall heaters. OPTIMA also reduces energy consumption in the fish auction hall - by up to 50 percent compared to conventional systems. Even more energy can be saved with the digital control system R.O.S.S.Y heating systems can be controlled with pinpoint accuracy and preheating times can be reduced to an environmentally friendly minimum depending on the weather periods and seasons.

The bottom line is a saving in heating costs of 50,000 euros per year. And extrapolated over the life cycle, a saving of 19,830 MWh of primary energy. Enough to heat around 700 average households for a year.

Incidentally, KÜBLER infrared heaters are also used in the Tresor, a decommissioned combined heat and power plant in Berlin's Mitte district. Now spread over six levels, connected by stairs and mezzanines with numerous rooms and niches, there are over 20,000 m2 of exhibition and event space for contemporary music, art and culture. Space that needs to be heated. The operators initially planned to use hot air heating. However, it soon became clear that too much energy would be lost due to the expected thermals towards the roof.

The alternative: 20 black lacquered infrared heaters from the OPTIMA series. However, the radiators are only part of the heating solution. A heat exchanger called O.P.U.S. X. It makes it possible to use the residual heat from the infrared radiators in the system H.Y.B.R.I.D. to heat water, for example. In this way, the operator of the safe recovers up to 15 percent of the energy that was previously lost to the environment.