Coupled Thermohydraulic and Biologic Modelling of Legionella Pneumophila Proliferation in Domestic Hot Water Systems

Doctoral dissertation Elisa Van Kenhove

Hot water is produced at temperatures above 60 °C, while we only use 40 °C at our taps. This reduces the risk of the residential hot water system becoming infected with Legionella pneumophila, a bacterium that can cause pneumonia. The high design temperatures contrast sharply with the ambitions for energy efficiency and hinder the optimization of the design and control of hot water systems. By blindly opting for fixed temperatures in practice, we are missing out on opportunities for energy savings or just taking health risks. Moreover, when a contamination of a system is detected, decontamination occurs more or less through "trial-and-error", which is very time-consuming, expensive and above all unsafe.

The general societal goal of this PhD is to reduce the energy demand for hot water and at the same time keep the risk of contamination with Legionella pneumophila low. This can be achieved by optimizing the design and control of hot water systems using simulation models.

In this PhD, a coupled thermal hydraulic and biologic simulation model was developed that allows to predict the growth of Legionella pneumophila and to test the effectiveness of decontamination techniques on an infected system. Based on this model, a control optimization algorithm was developed that makes it possible to combine a lower production temperature with a dynamic heat shock regime


Doctoral student: Elisa Van Kenhove
Public defense: 2018-12-18
Supervisors: prof. Arnold Janssens and prof. Jelle Laverge

Examination Board:
Prof. Dr. Ir. Luc Taerwe (UGent, chairman)
Prof. Dr. Ir. Arch. Arnold Janssens (UGent, supervisor)
Prof. Dr. Ir. Arch. Jelle Laverge (UGent, supervisor)
Dr. Ir. Caitlin Proctor (Purdue University)
Prof. Dr. Ir. Ivan Verhaert (UAntwerpen)
Ir. Bart Bleys (WTCB)
Prof. Ir. Wim Boydens (UGent, Studiebureau Boydens)
Prof. Dr. Ir. Michel De Paepe (UGent)

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