Three-dimensional numerical model of heat losses from district heating network pre-insulated pipes buried in the ground

The purpose of the paper is to investigate the challenges in modelling the energy losses of heating networks and to analyse the factors that influence them. The verification of the simulation was conducted on a test stand in-situ and based on the measurements of the testing station, a database for the final version of the numerical model was developed and a series of simulations were performed. Examples of the calculated results are shown in the graphs. The paper presents an innovative method of identify the energy losses of underground heating network pipelines and quantify the temperature distribution around them, in transient working conditions. The presented method makes use of numerical models and measured data of actual objects.The dimensions of the pipelines used were 6m wide, 8m high and 1m in depth, while they were simulated under conditions of zero heat flow in the ground, in the perpendicular to the sides direction of the calculated area and considering the effects of ground's thermal conductivity. The mesh was developed using advanced functions, which resulted its high quality with the average orthogonal quality of 0.99 (close to 1.00) and Skewness of 0.05 (between 0.00 and 0.25). To achieve better accuracy of the simulation model, the initial conditions were determined based on the numerical results of a three-dimensional analysis of heat losses, in steady state conditions in a single moment. The validation process confirmed the high quality of the model, as the differences between the ground temperatures were approximately 0.1°C

Do you see what I see? Exploring differing awareness of the same situation

Fundamental limits on the human ability to process all available information in real-world situations necessarily require that some information is filtered out by attentional processes, and so that information is not used to build ‘situation awareness’ (SA). The implication is that two (or more) people in the same situation may not perceive it in the same way, nor make the same decisions as to how to operate. Such differences in perception can become very important in safety critical situations such as the one that we report here—firefighter attendance at a road-traffic collision (RTC). Using a desktop virtual reality simulation of a RTC, we examined firefighters’ awareness of their situation (SA)—and also their understanding of what aspects of that situation are relevant to the successful completion of their task (situation understanding, SU). Our data, collected from 685 firefighters, suggest that the firefighters showed pronounced individual differences in the amount of information they accepted when building SA, but that they were almost universally predisposed to believe that information was relevant to their task (even though it may not have been). Non-firefighters, when compared with firefighters were generally more likely to accept a wider range of information spatially distributed across the RTC situation, but less likely to believe it to be relevant. The implication of our data is that individuals in the same situation may perceive that situation in different ways due to the way they handle the available information—and that training and experience affect that perception

Do you see what I see? Exploring differing awareness of the same situation

Fundamental limits on the human ability to process all available information in real-world situations necessarily require that some information is filtered out by attentional processes, and so that information is not used to build ‘situation awareness’ (SA). The implication is that two (or more) people in the same situation may not perceive it in the same way, nor make the same decisions as to how to operate. Such differences in perception can become very important in safety critical situations such as the one that we report here—firefighter attendance at a road-traffic collision (RTC). Using a desktop virtual reality simulation of a RTC, we examined firefighters’ awareness of their situation (SA)—and also their understanding of what aspects of that situation are relevant to the successful completion of their task (situation understanding, SU). Our data, collected from 685 firefighters, suggest that the firefighters showed pronounced individual differences in the amount of information they accepted when building SA, but that they were almost universally predisposed to believe that information was relevant to their task (even though it may not have been). Non-firefighters, when compared with firefighters were generally more likely to accept a wider range of information spatially distributed across the RTC situation, but less likely to believe it to be relevant. The implication of our data is that individuals in the same situation may perceive that situation in different ways due to the way they handle the available information—and that training and experience affect that perception