Circular economy meets building automation

TL;DR

The paper addresses circular economy goals by reusing discarded smartphones as edge compute resources for building energy management. It compares two predictive control approaches—model-based MPC with horizon $N$ and data-driven SMM-PC—alongside a smartphone-enabled communication test, validated with Termux, MQTT, REST, and OPC in the NEST facility. Results demonstrate technical feasibility with satisfactory control performance and latency compatible with building dynamics, indicating potential for energy management and ancillary services as mobile hardware improves. The work highlights environmental and operational benefits of leveraging end-of-life devices while outlining security, stability, and scalability challenges that warrant future lifecycle analyses.

Abstract

This paper demonstrates the concept of reusing discarded smartphones to connect the end-of-life of e-wastes with the start-of-life of smart buildings. Two control-related and one communication-related case studies have been conducted experimentally to evaluate applicability. Diverse controlled systems, control tasks, and algorithms have been considered. In addition, the sufficiency of communication with external agents has been quantified. The proof-of-concept experiments indicate technical feasibility and applicability to typical tasks with satisfactory performance. As smartphones improve over time, higher computing performance and lower communication latency can be expected, enhancing the prospect of the proposed reuse concept.

Figures (6)

• Figure 1: The NEST building in Dübendorf, Switzerland. Copyright @ Empa.
• Figure 2: Software and information exchange setup for the experiments. The images of experimental facilities are sourced from nest.
• Figure 3: Control-related case studies composed of diverse controlled systems, control tasks and algorithms.
• Figure 4: Setup of case studies for communication delay identification. The figure on the left shows the network configuration of three information exchange paths. The figure on the right illustrates the calculation of round-trip delays.
• Figure 5: Experiment results of control-related case studies. The figure on the left shows room temperature control results, where the black dashed lines indicate the comfort limits and the blue line shows the realized temperature trajectory. The figure on the right shows battery reference tracking control results, where the black dashed line shows the reference signal and the blue line shows the measured SOC.