Edoardo Alessio Piana

Hydraulic balancing strategies: A case study of radiator-based central heating system

With energy efficiency regulations coming into force, the retrofitting of existing plants has become mandatory in many European countries. The application of thermostatic radiator valves is a cheap, effective solution in case of radiator-based hydronic plants, but it requires the distribution system to be re-engineered and, in some situations, further adjusting devices to be added. In this paper, the behaviour of a vertical distribution heating system has been simulated with the aim of analysing the outcome of different hydraulic balancing strategies and proposing a method to identify the most suitable option. The common problem of noisy valves has been examined and the cost impact of the different solutions has also been considered. Practical application : This paper applies simple calculation tools to explore the impact of different balancing solutions to a real building, using an approach that could valuably assist the practitioner in the decision process.

Dynamic and acoustic properties of a joisted floor

Lightweight structures find more and more applications in both vehicle and ship industries. To meet a growing demand, a variety of different types of joisted panels have been developed during the last few decades. One of the problems to deal with is the assessment of the acoustic performances of such panels once they are already mounted in their final place. In this case, it can be of importance to find a way to characterise their dynamic and acoustic properties, such as bending stiffness, internal losses and sound reduction index through non-destructive testing. A method for a quick determination of the bending stiffness of a lightweight joisted floor is presented. On the basis of the apparent bending stiffness and of the losses, it is possible to predict the sound reduction index of the panel in a fairly simple way. The results obtained from the mobility tests have been compared to the measurements carried out according to the ISO standard procedure.

Accurate prediction of the corona noise produced by overhead transmission lines

The paper presents the results of a critical analysis of the most important prediction methods of radio-interference and acoustic noise produced by power transmission lines available in the technical literature. A code has been implemented in the MATLAB environment to improve the quality of the predictions, and the results of a preliminary validation of the tool are presented. Particular attention is given to the applicability to non-conventional geometries of the lines.