Abstract:In the present paper, the energy performance of buildings forming a school centre in the northwest of Spain was analyzed using a transient simulation of the energy model of the school, which was developed with TRNSYS, a software of proven reliability in the field of thermal simulations. A deterministic calibration approach was applied to the initial building model to adjust the predictions to the actual performance of the school, data acquired during the temperature measurement campaign. The buildings under study were in deteriorated conditions due to poor maintenance over the years, presenting a big challenge for modelling and simulating it in a reliable way. The results showed that the proposed methodology is successful for obtaining calibrated thermal models of these types of damaged buildings, as the metrics employed to verify the final error showed a reduced normalized mean bias error (NMBE) of 2.73%. It was verified that a decrease of approximately 60% in NMBE and 17% in the coefficient of variation of the root mean square error (CV(RMSE)) was achieved due to the calibration process. Subsequent steps were performed with the aid of new software, which was developed under a European project that enabled the automated calibration of the simulations.

The presence of four biogenic amines in Chilean Gauda cheese was studied, and the effect of certain factors may influence the production of those amines. Histamine, tyramine, putrescine and cadaverine were quantified with high-performance liquid chromatography (HPLC), in cheeses from the three major Chilean cheese manufacturers. Multiple regression analysis revealed that water activity, free amino acid content and the Enterobacteriaceae count all favoured production of biogenic amines. The total amount of biogenic amines in the samples studied was between 47.9 and 150.5 mg/kg of cheese, much lower than that associated with a possible consumer health risk (1000 mg/kg).

Monitored variables in biomass combustion devices, such as emissions or temperature, are usually characterized by their averaged values over the entire process, although they tend to present a pulsating behavior. This assumption induces instantaneous errors when experimental data are used in numerical simulation. The interest in obtaining high‐quality experimental information for a proper model validation leads to find an alternative to describe them and to discern which operating variables are the main ones responsible for those fluctuations. The application of frequency‐domain tools, such as coherence, is proposed as a useful solution for determining if the emission and temperature profiles are intrinsically related to any known periodical signal, such as the feeding cycle.

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Climate change and fossil fuel depletion foster interest in improving energy efficiency in buildings. There are different methods to achieve improved efficiency; one of them is the use of additives, such as phase change materials (PCMs). To prove this method's effectiveness, a building's behaviour should be monitored and analysed. This paper describes an acquisition system developed for monitoring buildings based on Supervisory Control and Data Acquisition (SCADA) and with a 1-wire bus network as the communication system. The system is empirically tested to prove that it works properly. With this purpose, two experimental cubicles are made of self-compacting concrete panels, one of which has a PCM as an additive to improve its energy storage properties. Both cubicles have the same dimensions and orientation, and they are separated by six feet to avoid shadows. The behaviour of the PCM was observed with the acquisition system, achieving results that illustrate the differences between the cubicles directly related to the PCM's characteristics. Data collection devices included in the system were temperature sensors, some of which were embedded in the walls, as well as humidity sensors, heat flux density sensors, a weather station and energy counters. The analysis of the results shows agreement with previous studies of PCM addition; therefore, the acquisition system is suitable for this application.