Piezo-Klett: Development of piezoelectric hook-and-loop application for the energy supply of active sensor technology in the building industry

Status

completed (August 2022)

Starting point, methods and results

Considering the high contribution of the building sector to climate change and also environmental pollution (in the form of e.g., energy consumption, CO₂ emissions, resource consumption, waste generation), it is important to increase the resilience of buildings and cities through the adaptability of building elements and building components to different usage scenarios, duration and the service life of building components.

Resilient buildings therefore require, on a structural level, a deconstruct-able design of the interfaces between short-lived and long-lived as well as materially heterogeneous components. In practice, however, non-destructive deconstruction is seldom or never applied because the design does not permit it or it involves a great deal of effort, as well as construction demolition phases are closely timed, and person-hours represent a considerable cost factor.

Resilience in the building industry can only be established with the corresponding knowledge about the built structure. Through digitalization processes in the building industry, by means of systems and technologies that provide detailed knowledge about the status quo and the "history" of the individual building components, "predictive modelling" or "predictive maintenance" can open up targeted component replacement, as well as recycling and reuse. Active sensor systems such as the NETBEE sensor interface from NET-Automation GmbH are particularly suitable for this purpose. This product can be combined with different sensors, enables measurements and transmissions even outside the readout cycle, does not require the additional use of readout devices, can react independently to limit or threshold value exceedances (e.g., temperature, CO₂) and offers a local memory. The installation of active sensors is costly due to the required cabling and is especially complicated when sensors are installed in existing buildings. In addition, the lifetime of the power supply by means of batteries is very limited in the case of wireless installation.

In the context of this constructive and energy-technical problem, as with regard to the solution of the information-technical requirements for resilient buildings, the industrial research "Piezo-Klett" deals with the application of piezoelectric components, as well as the combination with the Velcro connection, with regard to the approach to supply the sensor interface NETBEE with energy autonomously. Voltage and load changes occurring directly at component interfaces, caused by environmental conditions (e.g., wind), are used to operate so-called energy harvesting as a result of the piezoelectric effect. In addition to piezoelectric products on the market (such as the DuraAct surface transducer, the piezo disk, piezo actuators and piezo rings), a particularly innovative approach to exploiting this effect exists in the "piezo textile", developed by researchers Anja Lund, Karin Rundqvist, Erik Nilsson, Liyang Yu, Bengt Hagström and Christian Müller at Chalmers University. This is accordingly investigated in the present project.

The aim of the project is to investigate piezoelectric components, as well as the combination with the Velcro connection, for the self-sufficient supply of active sensors. As well as to organise accruing data about their transmission cycles. Thus, approaching a new type of self-sufficient energy system for active sensors. The desired result is a verification of the project idea by quantifying the recoverable electrical energy depending on the application case as well as a comprehensive, interdisciplinary gain in knowledge about individual constructive concepts and applications in architecture and construction.

The object of investigation is formed by effects on (buildings and parts of) the structural engineering design, joining technologies, piezo-technological components, the NETBEE sensor interface, as well as by data transmission and data management. In these areas, a systematic literature research, concept development and an experimental investigation of individual system elements (on the constructional, electrotechnical and digital level) were carried out.

In total, 62 constructional concepts could be developed on a basic level and 13 selected concepts could be developed in depth (construction, impact, piezo technology, joining technology), three of which are presented in this report. Furthermore, as shown by test results of two parallel-connected "piezo-textile-tapes" under dynamic tensile load, it would be theoretically possible to perform five measurements in 24 hours or one transmission in 20 days with the NETBEE module. As with 12 piezo textile tapes connected in parallel, 1 measurement in 0.5 h or one transmission in 1.6 days. In the context of developing harvest electronics to supply the NETBEE module by means of energy harvesting, it was possible to create a technical basis (using pre-switching electronics systems and firmware). On a digital level, energy management was optimised, and a basis for a database for climate and building component data was created. The data was visualised in a clear and thus easy-to-interpret form.

As could be shown, at the technical level, a self-sufficient operation of active sensor systems is conceivable by means of energy harvesting. This means that in the future, effects and vibrations on buildings and parts of buildings could be used specifically as energy generators and permitted by the design of the building itself. This means a rethinking of construction practice. In addition, it was found that the application of the envisaged new system requires extensive further research and development due to the high complexity and interdependencies between different areas.

Project management

Institute of Architecture Technology, Graz University of Technology

Project or cooperation partners

• Laboratory for Structural Engineering, Graz University of Technology
• Axtesys GmbH, Graz
• NET-Automation GmbH, Zeltweg
• Anja Lund, Chemistry and Chemical Engineering, Chalmers University of Technology, Sweden

Graz University of Technology,
Institute of Architecture Technology
Univ.-Prof. Dipl.-Ing. Architekt Roger RIEWE
Rechbauerstr. 12/I
A-8010 Graz
Tel.: +43 (316) 873 6300
E-mail: riewe@tugraz.at
Web: www.tugraz.at/en

Deputy project manager
Dipl.-Ing. Matthias RAUDASCHL
Tel.: +43 (316) 873 6308
E-mail: matthias.raudaschl@tugraz.at

Deputy project manager
Dipl.-Ing. Toni LEVAK
Tel.: +43 (316) 873 6307
E-mail: toni.levak@tugraz.at