Hotels –

Energy and cost-efficient climate control at Hotel Bellevue

Located directly on the river Elbe, the Bellevue Hotel Dresden offers its guests one of the most beautiful views of the historic baroque city. In 2020, the listed building became the first hotel in Germany to join the exclusive Bilderberg Hotels collection. The hotel decided to integrate the room air conditioning into the building management system to make the air conditioning system more energy- and cost-efficient. The combination of the JOY Modbus room thermostat, the SAB+ energy-harvesting radiator valve and the SRW03 wireless window contact from Thermokon provide valuable saving opportunities.

The Bilderberg Bellevue Hotel Dresden relies on room thermostats from Thermokon

The Bellevue Hotel Dresden looks back on an eventful history. The old building was constructed between 1723 and 1727 and is the only surviving building complex on the famous “Große Meißner Gasse”, a once frequently used trading street. The building, which was used over the centuries as a residence, brewery and malt house, as a chancellery and as the Ministry of Justice, survived the the Second World War unscathed and was extensively extended during the GDR era, giving it its current appearance. Formerly being an Interhotel, it became one of the leading addresses for foreign guests. Important political events such as the reunification negotiations in 1989 and the G8 summit in 2007 also took place here. Today, both the baroque centre building and the architecturally inspired extensions are listed buildings and offer guests a unique ambience with a view at the Hofkirche, the Semper Opera House and the historic old town on the opposite bank of the Elbe.

Goal: Comprehensive integration into the Building Management System

The owner combined the acquisition of the building with extensive modernisation investments. As the existing air conditioning systems no longer met current energy-efficiency requirements, this included a fundamental modernisation of the building services in a total of 328 hotel rooms. In particular, the hotel management found the manual regulation of the room temperature via the radiators and the outdated fan coil units to be inadequate. "Even when guests were absent, the heating or cooling often continued to run. This led to significant energy losses," explains Mario Arndt, Managing Director of Arndt Badsanierung GmbH & Co. KG. The company, which operates throughout Germany, is a specialist for renovation work in hotel facilities and was requested by Bellevue to modernise the building services.

The concept developed by Arndt Badsanierung envisaged integrating the entire room air conditioning system into the building management system using state-of-the-art technology to ensure resource-efficient operation. This included replacing the existing fan coil units with fan coil units with energy-efficient EC motors and low noise levels.

The radiators and fan coil units were to be controlled based on presence detectors and depending on the occupancy status of the rooms: "If the presence detector recognises that a room is empty, a defined standby temperature is kept through the building management system. If, on the other hand, the detector registers presence, individual control by the guest is possible overwriting the system. In this way, unwanted wastes of energy can be effectively prevented," explains Mario Arndt.

Integrating the room air conditioning into the building management system also allows the Bellevue Hotel's technical service to check and control all room statuses and device functions remotely – a further boost in terms of efficiency and comfort.

Wireless EnOcean technology from Thermokon

In his search for an efficient partner to automate the heating system, Mario Arndt opted for Thermokon: "In addition to the high product quality, the tangible time and cost benefits during on-site implementation were a particular advantage." The sensor technology expert suggested a powerful combination of the JOY room thermostat with Modbus interface, the SAB+ energy-harvesting radiator valve and the SRW03 wireless window contact. With its flat housing, the elegant surface made of scratch-resistant glass and the generous LCD display with backlighting, JOY blends in with the high-quality appearance of the hotel rooms and makes controlling indoor climate simple and precise. Communication with the building management system is given any time through the Modbus interface.

Networking with the SAB+ energy-harvesting radiator valve and the SRW03 window contact is EnOcean radio-based and therefore also wireless as well as energy-harvesting. Thanks to solar cells and intelligent energy harvesting routines, the solution minimized the installation work at the Hotel Bellevue. By eliminating the need for regular battery changes, they also reduce the hotel's maintenance costs during operation. The energy savings during ventilation are also impressive: as soon as the status monitoring of the window contact detects an open window, the room air conditioning is automatically deactivated.

Reduce downtimes via Plug & Play

Another factor that was a top priority for the hotel management during the modernisation work was reducing downtime. "Loss of revenue due to the modernisation was to be avoided wherever possible. In this context, both the elimination of cabling between the room thermostat, window contact and radiator valve and the optional pre-configuration of the components proposed by Thermokon proved to be a significant time advantage," explains Mario Arndt.

In co-operation with WAGO, a leading supplier of innovative controls products for automation and connection technology, Thermokon had developed a concept based on a plug&play approach of the components via WAGO’s WINSTA-Box. Mario Arndt is extremely satisfied with the result: "The comparatively uncomplicated solution proved to be ideal for the rapid modernisation of the hotel rooms with the least possible downtime. This is extremely important both from the Hotel Bellevue's point of view and for us as the contractor. The modernisation at the Bellevue Hotel was a very promising first project with Thermokon." Another one is already in the starting blocks: the modernisation of a hotel in the Frankfurt area.

Deployed Products