Tag Archive for: Efficient

The new office building of mister*lady GmbH in Schwabach (photo source: LK Metall)

Dust-free feel-good climate without drafts on 4,500 sqm

The German fashion retailer mister*lady relies on energy-efficient heating without dust and drafts. LK Metall installed an innovative heating and ventilation system as part of a new construction of a logistics center for the German fashion retailer mister*lady in Schwabach. An investment that has already proven itself in many ways, emphasizes mister*lady managing director, Rudolf Kempter.

Background: mister*lady GmbH moved its headquarters from Nuremberg to Schwabach. In addition to the new central administration with an area of 6,000 m², two logistics halls with an area of 4,500m² each were built. Each hall has 10 gates, a room height of about 7.50 m and a room volume of about 75,000 m³.

In particular, the climate-friendly heating and ventilation of the logistics halls posed a challenge. Managing Director Kempter was faced with a choice. “The architect, general contractor and other consultants recommended different solutions,” he recalls, “so with new construction, it’s important to find out exactly what the requirements are.” Of course, the warehouse activities had to be taken into account: The approximately 22 mister*lady employees moved about 15 million parts in about one million packages per year in single-shift operation. Around 3,600 arrivals and departures took place at the 10 loading stations.

Since the production halls employ the company’s own staff, Kempter is particularly concerned about their well-being: “A modern and energy-efficient solution was important. To achieve a good indoor climate for our people, the temperature distribution must be even and free of dust and drafts. Rudolf Kempter deliberately decided against using gas-fired dark radiators.

Technical structure of the hot air generators
The warm air generators installed under the ceiling draw in waste heat rising from the hall – such as heat generated by lighting or solar radiation – and filter it. In addition, fresh outside air can be drawn in. The air passes a stainless steel combustion chamber to bring it to the desired room temperature. Turbulent flow of the exhaust gases is generated inside the heat exchange tubes arranged on the left and right, thus ensuring optimized heat exchange. Special air outlets and return air ceiling fans distribute the air flow draught-free in the hall. The hot air distribution is controlled automatically by means of PI differential temperature control via measuring sensors in the working area and on the ceiling.

A control system regulates the temperature of the system intelligently and adapted to the wishes of mister*lady: The hall is heated individually as required. The desired room temperature is freely programmable. After an installation period of only one week, mister*lady was able to put the systems into operation.

Costs in view
Looking back, after a first winter heating season, the managing director’s expectations have been met: “The employees are satisfied. The air layering is super, as promised. The air is distributed evenly. There are no cold or warm corners, no trace of drafts.” The energy consumption is also convincing: “On normal working days, we need an average of 320 m³ of gas during the cold season, which corresponds to a cost of about €80,” says Rudolf Kempter.

Especially in the transitional period, the system does not require the burner to be switched on. Then the accumulated heat under the hall roof is already enough. The return air ceiling fans then distribute it evenly back to where it is needed. Great climate should also prevail in the summer at mister*lady. Here, the good hall insulation and the ventilation system play the supporting role. At night, the system draws in the cold outside air and has already ensured pleasantly cool temperatures in the logistics hall by the time the shift begins in the morning. This makes extra air conditioning superfluous.

Advantage: less space required for hall expansion
Another advantage of the plant will only come into play in the future. Rudolf Kempter has further plans for the expansion of the hall. He would like to add a lattice mezzanine at mid-hall height for administration. No problem thanks to the intelligent air distribution of the RBW 125. “With our heating solution, even the employees on the first floor still get warm feet. In addition, there is no need to maintain a minimum distance, as is required for radiant heaters. The space consumption would have been enormous with probably up to 70 radiant heaters needed in the logistics area,” he concludes.

 

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.