Tag Archive for: Climate Protection

Hybrid heating

LK "Green-Climate-System (GCS)" Warm Air Heater

The Climate Protection Act has been in force since August 2021.
The German government has tightened climate protection targets and enshrined the goal of greenhouse gas neutrality by 2045. By 2030, emissions are already to be reduced by 65 percent compared with 1990.

Warm air heater RBW
LK Warm air heater RBW

LK Metallwaren offers three innovative solutions for the heating, ventilation and air conditioning of production, logistics and industrial halls. In order to achieve the climate protection targets in non-residential buildings, LK Metall has combined the RBW warm air heater and the REKU ventilation system with heat pump technology , as well as developing the new “Green Climate System”, which heats industrial halls without using gas as a fuel.

LK Warm air heater RBW with condensing boiler and heat pump technology
LK Warm air heater RBW with condensing boiler and heat pump technology

The hybrid heating system with gas and heat pump technology

The very efficient RBW warm air heater with condensing technology is extended with a heat pump package. The combination of gas as a fuel and heat pumps for heat exchange creates the hybrid heating system. Here, the heat pump takes over the heat generation mainly in the transitional period, i.e. in autumn and spring. In winter, on the other hand, the gas heating only switches on when the outside temperatures are too low to heat mainly with the heat pump.

With the air-to-air heat pump, the air is used as a heat source and thus an efficient and environmentally friendly operation is realized. The heaters in the warm air heater are piped to the heat pump and filled with R32 refrigerant. Additional fan units make independent operation of warm air heater and heat pumps possible. The air-to-air heat pumps used with the new R32 refrigerant significantly improve energy efficiency.

Comparison of the greenhouse potential of refrigerants
Graphic - Global Warming Potential (GWP) over 100 years
Graphic – Global Warming Potential (GWP) over 100 years
Source: IPCC Fourth Assessment Report. Global Warming Potential (GWP) over 100 years.

Compared: 2,088 (R410A) vs. 675 (R32). The advantages of hybrid heating are obvious. Hybrid heating reduces CO2 emissions by up to 30%, significantly reducing the need to burn fossil fuels. Another advantage of hybrid heating is the cooling function, which is provided by the heat pumps at all times. Especially in summer, this additionally improves the hall climate for the staff. LK hybrid heating is used in production and logistics halls. In the case of renovation, a gas hybrid heating system is subsidized by BAFA with up to 30 %.

The ventilation system REKU combined with heat pump technology

The LK ventilation systems REKU are often used in aerosol polluted production areas such as machining fabrications, welding shops and areas with high process waste heat. Filtrations up to class F7 ( New: ISO ePM 2.5) can be used in supply and exhaust air. The filter class can be adjusted depending on the application. With the integrated heat recovery system, up to 84% of the thermal energy contained in the exhaust air is transferred to the supply air via a plate heat exchanger using the counterflow principle. The outside air drawn in is thus heated and fed into the hall. With this technology, the supply air and exhaust air flow is separated from each other. Thus, heat from polluted air can also be used.

LK Ventilation system REKU with heat pump package
LK Ventilation system REKU with heat pump package

In summer, the process waste heat is discharged directly to the outside. The heat recovery is bypassed via a bypass to avoid unnecessary heating. A combination of the LK ventilation system REKU and an air-to-air heat pump does not require fossil fuels. As with the other system combinations with heat pumps from LK Metallwaren, the heating element can be operated for heating (direct condenser) or for cooling (direct evaporator). This added value helps to significantly improve the hall climate. Another advantage is that this combination is also subsidized by up to 35%.

The LK Warm Air Generator Green Climate System
The LK Warm Air Generator Green Climate System

The new LK “Green-Climate-System” (GCS) warm air heater

In order to conserve finite resources, the LK design engineers have developed the new CO2-neutral LK “Green-Climate-System (GCS)” Warm Air Heater developed for industrial halls from 4 m hall height. The “Green Climate System” does not use fossil fuels. The LK warm air heater is installed under the hall roof and draws in either hall air or outside air. Ventilation is provided by highly efficient radial impellers with EC motor technology. The passing air is heated via a heating coil connected to the heat pump. An upstream filter cleans the fresh and hall air supply from impurities. In case of very cold outdoor temperatures, it is possible to use an electric reheating coil. This covers peak loads without having to resort to a fossil fuel.

The system behaves similarly to the heating element in the heat pump in the domestic sector. Here, as in the systems already mentioned above, a heat pump with R32 coolant is used. The new system can thus heat and ventilate the hall during the winter months. In summer, ventilation and cooling is possible. With the new LK warm air heater “Green-Climate-System”, LK Metall relies 100% on the medium electricity and thus on regenerative energy sources. This makes the new plant system particularly eligible for subsidies.

Conclusion: LK Metall relies on energy efficiency and resource-saving systems with its entire plant technology in hall heating.


Warm air heater RBW - Gentle temperatures on 7,700 sqm

Three different temperature ranges for sensitive goods

Euphoniums, cajons and agogos – all these wonderful musical instruments can be found in Treppendorf in the Steigerwald in the 7,700 square meter logistics halls of the Thomann music store. In total, there are about 24,000 items here – from guitars and pianos to stringed instruments and various types of percussion instrument.

“We need a special indoor climate for storing musical instruments,” explains Stefan Thomann, co-founder and project manager for logistics at the music retailer. “The items are very sensitive; for example, if the humidity is too low, the tops of guitars can crack. With temperatures, constant air quality is especially crucial.”

Therefore, the company paid special attention to heating and air conditioning technology. Stefan Thomann: “For the pallet warehouse, we only had low temperature requirements because employees are not permanently working here. In the small parts storage area, on the other hand, we were aiming for a temperature of 16 to 17 degrees. But for incoming goods, it had to be a little warmer. The challenge with the technology: despite the three different temperature areas, it is one large, continuous hall.” This three-part temperature concept was realized by LK Metall. Two RBW direct-heated warm air generators with integrated mixed air equipment were used in the pallet and small parts warehouse, which were mounted on the hall ceiling between the two areas. An RBW warm air heater with integrated mixed air unit was also installed in the goods receiving area.

Music store Thomann
Music store Thomann

Evenly from the floor to the roof

The heating system is controlled by a building management system and several thermostats. If the temperature in one of the zones falls below a programmed set point, the respective heating system automatically turns on. Through the surface of the combustion chamber, the heat released by the burner is transferred directly to the passing air. Thus, up to 95 % of the energy used is converted directly into heat. In addition, further heat exchange of the flue gases takes place through the downstream, countercurrent heat exchange tubes, which are washed by the air flow along the entire length of the plant. At the end of the heat exchange pipes, the heated air leaves the plant via mixed air parts. Individually installed return air ceiling fans ensure uniform heat distribution over the entire height of the hall. A differential temperature control system also optimizes and reduces the temperature differences from the roof to the floor in the entire hall area to around 3 to 4 degrees.

A special feature of the system: the warm air generators can be used not only for heating, but also for ventilation. “In the summer months, the temperature in the hall is driven down by a summer night cooling system,” explains Harald Wimmer Sales Manager at LK-Metall. “This allows air temperature, air quality and air distribution to be adjusted as needed.”

Thanks to the finely tuned heating technology between the halls, the sensitive musical instruments will be safely stored in the future with regard to room temperature.

Efficient and climate-friendly! Heating solutions for large production halls

Regulate 32,000 sqm to constant 18 °C hall temperature

The RBW decentralized warm air generators from LK Metall are an efficient and climate-friendly heating solution for large production halls.

In order to heat the new light-flooded production hall with a total area of around 32,000 m2 evenly and effectively during the annual heating period and to achieve a pleasant hall climate in summer, the axle manufacturer commissioned Kessler+Co. GmbH & Co KG from Abtsgmünd, Germany, provided the LK Metall company with a climate-friendly heating system using effective condensing boiler technology.

A total of 12 decentralized warm air generators of the RBW type were installed over a wide area under the hall ceiling. In order to achieve a uniform temperature of around 18 °C during the heating period, rising hall air is extracted, filtered and heated via the combustion chamber and the designed heat exchangers and fed back into the hall without drafts. The decentralized warm air generators are each heated with a natural gas-fired gas blower burner.

Warm air heater RBW for Kessler+Co
Warm air heater RBW for Kessler+Co

Additional use of waste heat

The rising warm hall air from process heat and the solar radiation via the skylights are an additional usable heat source for the warm air generator. The hall air extracted and filtered under the hall ceiling mixes with supplied fresh air. Due to the additional use of waste heat in combination with the modulating burner operation of the units, the RBW warm air generators consume significantly less energy.

“The use of the decentralized warm air generators type RBW for heating production halls is a convincing contribution to climate protection,” says Harald Wimmer Sales and Marketing Manager for hall heaters at LK Metall, “Because the additional use of waste heat means that less fossil fuel is consumed. This significantly reduces CO2 emissions.” The heat output range of RBW warm air heaters is from 40 kW to 160 kW. Special knitted metal filters made of stainless steel clean the hall air from dust particles and aerosols from production. Around 90 installed return air ceiling fans reduce the temperature stratification over the entire hall height to 0.3 °C to 0.5 °C per rising meter. These are regulated by sensors in the ceiling and floor areas.

Cooled hall air in summer

In the summer months, the RBW warm air generators improve the hall climate through the mixed air device. An automatic night-summer ventilation control system uses the cool outside air at night to cool the hall air, reducing accumulated heat from the day back to a comfortable temperature. “Thus, the RBW warm air heaters are also used in summer to maintain a pleasant daytime temperature,” said Harald Wimmer after commissioning the heating systems at Kessler+Co.

Central control from PC

A modern PLC flexibly controls the warm air generators. All settings are made via the respective touch displays on a total of four control cabinets. In order to be able to operate the twelve warm air generators centrally via a PC, the systems were integrated into the company’s network. Regardless of the size of the production and manufacturing halls, the RBW warm air heaters from LK Metall are a flexible, efficient and infinitely scalable heating solution with an extremely high efficiency of up to 99% based on the calorific value, thanks to the decentralized installation under the hall roof.