Sustainable building automation in heritage buildings

Modern building control technology is a central element of energy- and cost-efficient climate control in buildings. Particularly in heritage buildings, sustainably functioning building automation requires a great deal of sensitivity when it comes to choosing the right products and technologies. When modernizing the building services and improving the air conditioning in the Bellevue Hotel Dresden, those responsible also relied on products that use EnOcean energy harvesting technology.

Modernizing building services and efficiently designing room air conditioning
The Bellevue Hotel Dresden looks back on an eventful history. Built between 1723 and 1727, the only remaining building complex on the famous Große Meißner Gasse was also the scene of politically significant events, including the reunification of Germany in 1989 and the G8 summit in 2007. The new owner of the now heritage-listed hotel with 328 rooms decided to comprehensively modernize the building services. Particular focus was placed on correcting the manual regulation of the room temperature via the radiators as well as the outdated fan convectors, which were also in operation when guests were absent and had been proven to lead to energy losses and increased energy costs. Arndt Badsanierung GmbH & Co. KG was awarded the contract for the installation of energy- and cost-efficient room air conditioning solutions. For the implementation, the company relied on room thermostats and radiator valves from Thermokon’s “EasySens” wireless system, which makes use of the EnOcean energy harvesting solution.

Integrating room air conditioning into the building management system
“The key to the energy- and cost-efficient design of the room air conditioning was the decision to equip it with state-of-the-art technology and integrate it into the building management system. As a result, the hotel’s technical service is now able to centrally control all room statuses and device functions,” says Mario Arndt, Managing Director of Arndt Badsanierung. To ensure resource-efficient operation, the fan coils were replaced with fan coil units with energy-efficient ec motors and low noise levels. The radiators and fan coil units were linked to the presence detector and are now controlled depending on the occupancy status of the rooms: if the presence detector detects that a room is empty, a defined standby temperature is activated via the building management system. If a guest is present, on the other hand, the system enables individual control by the guest.

“The use of high-quality sensor systems from Thermokon, in particular the combination of the JOY room thermostat with Modbus interface and the EnOcean-based energy self-sufficient SAB+ electronic radiator valves and SRW03 wireless window contacts, was essential for the successful automation of the heating technology,” emphasizes Timon Deisel, Thermokon Sales Manager Germany. With its flat housing, scratch-resistant acrylic glass surface and backlit LCD display, JOY blends in with the look of the room and makes controlling the indoor climate simple and precise. Communication with the building management system takes place via the integrated Modbus interface. Networking with the SAB+ radiator valve and the SRW03 window contact is radio-based and therefore also wireless. Thanks to their solar cells and intelligent energy harvesting, the two solutions reduced the installation work at the Hotel Bellevue to a minimum. By eliminating the need for regular battery changes, they also reduce the hotel’s personnel 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.

Added value through energy harvesting, battery-free wireless switches and window contact sensors
“This project demonstrates the benefits of our energy harvesting technology and our sensor products. The use of alternative energy sources from the environment, such as temperature, movement, and light in this case, as well as our integrated battery-free wireless switches and window contact sensors, which provide information about open windows, for example, have contributed to increasing the energy and cost efficiency of the Bellevue Hotel Dresden,” summarizes Markus Florian, CCO at EnOcean. Savings were also achieved during the modernization by reducing downtimes, saving on cabling and through external pre-assembly of the components. In addition, Thermokon worked with Wago to develop a concept based on ready-to-plug-in cabling of the components via Winsta-Box. That way, commissioning in the rooms could be carried out quickly, safely, and error-free via plug & play.

Solutions for building automation in existing buildings
The Building Energy Act 2024 (GEG) aims to promote the use of renewable energies in the building sector and also to end the use of fossil fuels by 2045. Sustainable building automation in listed buildings poses a particular challenge in this regard, especially when it comes to anchoring energy- and cost-efficient room air conditioning. The modernization of the building services at the Bellevue Hotel Dresden demonstrates the potential that can be realized when all parties involved work together in a goal-oriented and responsible manner. Together with its partners, EnOcean will continue to support owners and tenants of houses, buildings and industrial facilities with high-quality products and sustainable IoT solutions, especially in the area of retrofitting and energy optimization of existing buildings.

Image – Lobby of the Bellevue Hotels Dresden ©Lichtwerk Christian Plaum