Background: Legionnaires' Disease occurs worldwide. Many authorities have guidelines and regulations to prevent and control Legionella in water systems. These regulations are based on often very limited field and laboratory observations and measurements. They are, therefore, very different from country to country. This paper aims to map the existing regulatory framework on Legionella control in the world in order to assess the feasibility of regulatory unification. Methods: The paper gives an overview of the different standards, guidelines and recommendations and of how various authorities and/or countries deal with Legionella infection. A three-step process is followed to identify current regulations. Results: Although Legionella is a global concern with a common scientific base, the regulatory framework is different from country to country. The current guidelines and standards are not the best possible ones, still there is a broad unification of underlying principles despite different regulatory frameworks. Common principles across regulations are avoiding and monitoring critical spots, avoiding water stagnation and the requirement of sufficiently high temperature (above 60°C, below 25°C). Differences between regulations are the target group and dangerous Legionella concentration levels. Discussion and conclusion: The comparative analysis of the frameworks is a good starting point to reach future regulatory unification based on their common ground.

The energy needed for the production of domestic hot water represents an important share in the total energy demand of well-insulated and airtight buildings. Domestic hot water is produced, stored and distributed above 60°C to kill Legionella pneumophila. This elevated temperature is not necessary for domestic hot water applications and has a negative effect on the efficiency of hot water production units. In this paper, system component models are developed/updated with L. pneumophila growth equations. For that purpose different existing Modelica pipe and boiler models are investigated to select useful models that could be extended with equations for simulation of bacterial growth. In future research, HVAC designers will be able to investigate the contamination risk for L. pneumophila in the design phase of a hot water system, by implementing the customized pipe and boiler model in a hot water system model. Additionally it will be possible, with simulations, to optimise temperature regimes and estimate the energy saving potential without increasing contamination risk. Keywords: domestic hot water (DHW), Legionella pneumophila, pipe model, boiler model, contamination risk, energy use Attachment Annex 1-Approach 1 to determine multiplication time (y and yb) Annex 2-Approach 2 to determine multiplication time (y and yb) Annex 3-Explanation of conservation equations Annex 4-Pipe and boiler models: reasons for non-retention Annex 5-Simulation model components used in pipe and boiler component Annex 6-Understanding the simulation log basics

The energy needed for domestic hot water represents an important share in the total energy use of well-insulated and airtight buildings. One of the main reasons for this high energy demand is that hot water is produced at temperatures above 60°C to mitigate the risk of contaminating the hot water system with Legionella pneumophila. However, this elevated temperature is not necessary for most domestic hot water applications, and has a negative effect on the efficiency of hot water production units. A simulation model has been developed which proposes an alternative to this constant 60°C by predicting the Legionella pneumophila concentration dynamically throughout the hot water system. Based on this knowledge, a hot water controller is added to the simulation model that sets a lower hot water comfort temperature in combination with heat shocks. In this paper, the simulation model is used to estimate the energy saving potential in a case study building, at the level of the heat production system by reaching higher production efficiencies. Three different production units, namely an electric boiler, heat pump and solar collector have been investigated. The controller is expected to become an alternative for the current, energy intensive, high temperature tap water heating systems.

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Historic homesteads can be found on a large scale in Europe and particularly in Flanders. In Flanders there are hundreds of homesteads in desperate need of renovation. Within the framework of the Europe 2020 objectives both CO 2 emission and energy use need to be reduced with 20% by 2020. Unlike for the average residential building renovation, focus lies on synergy between respect to heritage and achieving an optimal energetic effectiveness. The object of this research is a case study homestead in Bruges, named the Schipjes. The first step in energy efficient renovation is to lower energy use by optimizing the building physics, therefore dynamic simulations in Modelica are performed to evaluate primary energy demand, especially for heating, and thermal comfort. The second step is the choice of the most energy efficient technical installations for a district heating system as will be used for Schipjes. Five different scenarios or combinations of heat production and distribution systems are developed as input options for future research simulations and energetic equations in Modelica.