Johannes Peter Fütterer

Simulation-based implementation and evaluation of a system of systems optimization algorithm in a building control system

The objective of this research is to evaluate the performance of a system of systems optimization algorithm, namely, L4G-PCAO, in building energy systems. Since the test bed of this research is an office building with more than two hundred occupiers, the heating and cooling demands of the building must always be fully satisfied. Consequently, changes in the currently-installed control system cannot be made forthrightly. Therefore, fresh ideas like implementation of new control strategies or optimization algorithms should be firstly put to the test via dynamic simulation, which makes engineers capable of examining new control and optimization strategies. The performance should then be analyzed and evaluated before implementing in the use case. This paper presents a strategy for simulation-based implementation of L4G-PCAO in a building energy system and also evaluates its performance. The results show that it is not only possible to conserve energy by applying this newly-developed optimization algorithm to existing control systems, but also it can shift the usage of energy sources in a more environment-friendly direction.

System of Systems theory as a new perspective on building control

Energy efficiency of buildings has been identified as a core element in facing the climate change and the scarcity of energy resources. The energy supply system for a building is, especially with view on thermal interrelations, a highly complex and heterogeneous system that emerges jointly with the building construction, the users behavior, the weather conditions and the surrounding energy and price policy to a real system-of-system. The building control system as the “intelligent instance” of the System of Systems (SoS) takes a special role in realizing the potential of the joint operating constituent systems due to the energy efficiency of the building or district. We apply SoS as an innovative engineering approach to a complex energy system.

Demonstration of an easy-to-apply, automated control tuning method for typical PID control loops in building energy systems

Within custom-made energy or HVAC systems, control quality of the widespread PI and PID controllers is in general poor due to high tuning costs for each controller and almost unique specifications of each controlled system. We propose a control tuning method, which needs as little as possible a priori knowledge, which runs as far as possible automated, and which is applicable for all state-of-the-art building automation systems. The method is non-adaptive and suitable for initial set up as well as retuning purposes. We demonstrate the method within a multifunctional office building with a complex energy system, where the methods application led to high control quality improvements.

A mode-based implementation framework for advanced control methods in building automation systems with Petri-Nets

Energy efficiency of buildings and districts is a core element in facing the climate change and scarcity of energy resources. A major domain for improving energy efficiency is building automation and control. Especially the application of advanced control methodologies requires special attention during the engineering process in order to guarantee for a meaningful, reasonable and comprehensible system behavior. In this paper, we present the concept of operating modes for increasing both, the operability and the applicability of advanced control methods in building energy systems. Referring to process automation methods, we introduce Petri-Nets as a powerful description method for mode-based building control development.

Tuning of PID Controllers within Building Energy Systems

Within this thesis, an extended PID auto-tuning algorithm for HVAC systems and building energy systems using the advances in computational power in recent years that is easily applicable to all state-of-the-art building energy management systems and building automation and control systems through the use of cloud-based services and standardized communication protocols is developed and demonstrated. The algorithm is derived based on a review of theory and related work. A simulation study investigates the main characteristics of the proposed algorithm. Its real-life demonstration takes place in a multifunctional office building during full operation. Conducted in order to enable this research, the thesis presents the extension of the demonstration building’s building automation and control system. On the one hand, the system is equipped with an extensive monitoring system; on the other hand, it is extended with an interface system that turns it towards a system that is able to interact with an IP-connected, thus cloud-like, server infrastructure. The major contributions of this thesis are an innovative PID tuning algorithm, its general configuration suggestions for application within different types of control loops and its demonstration. Its applicability is proved and demonstrated within a simulaton study and real-life experiments. The results for a classical real-life building automation system and different classically PID-controlled loops show an amelioration of the tuned systems’ control performance in 68 % of the algorithm’s applications. The application of the algorithm leads to control quality improvements of up to 90 %, accounting for both, simulation and field study, following the integral time-weighted absolute error criterion, ITEA and in comparison to a state-of-the-art adaptive auto-tuning method. Additionally, in order to investigate the applicability of alternative control infrastructures as they might occur in future cloud-based building control systems, such control infrastructures are implemented and tuned with the proposed algorithm. Their tuning is far less successful, indicating that data resolution and transmission times are important and should be regarded in future applications. Moreover, a technical structure for cloud-based services towards building operation optimization is proposed and demonstrated with PID control loop tuning as the use case. Finally yet importantly, a real-life demonstration bench for advanced control research as well as a simulation framework for the same purpose are developed.

Gebäudeautomationssysteme in der Praxis

This document is a whitepaper containing the author‘s findings made by an online questionnaire. This document is published under Creative Commons BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article as: J. Fütterer, T. Schild, D. Müller, Gebäudeautomationssysteme in der Praxis, Whitepaper RWTH-EBC 2017-001, Aachen, 2017, http://dx.doi.org/10.18154/RWTH-2017-05671