Legionella pneumophila on tap : optimising design of domestic hot water systems using building energy simulation

Legionella is naturally present in water. It is almost undetectable in water that enters the building, but in Domestic Hot Water (DHW) installations situations can occur that stimulate Legionella growth. The most important growth factor at these points of risk is temperature. A simulation model is developed that allows to investigate the presence of Legionella in DHW systems. In this paper it is used to test the effectiveness of a renovation measure on a system contaminated with Legionella of four case study buildings with 800 apartments. To compile the simulation model, temperature, flow rate and Legionella measurements are performed in these buildings. Hot water temperature optimisation throughout the system is researched by investigating the influence of insulating this system to keep it healthy and energy efficient on the long term through simulations