The global increase in energy demand and exponential exhaustion of fossil recourses has favored the development of new systems of electricity production. Photovoltaic solar energy is undoubtedly one that has the highest application in housings, due to its simplicity and easy implementation. In this work, a new prototype of photovoltaic solar tracker with Arduino platform was developed. Feedback control system that allows carrying out solar tracking with two axes using a stepper motor and linear actuator was established through an electronic circuit based on photodiodes. Moreover, real construction of the prototype was carried out, where the effectiveness of the design and its capacity to draw a maximum benefit of an incident radiation can be observed, placing the panel perpendicularly to the received energy and improving its performance for its application in future installations in housings. Results obtained from the comparison between the developed prototype and a static panel oriented according to the latitude of the area, show about 18% energy gain.

The production of energy at the global level is conditioned by the use of fossil fuels that have a great environmental impact. In the last decades, renewable energy production systems have been implemented, and networks of nearly zero-energy buildings have been created, with a consequent complexity in the design phase in order to optimize the results. In this way, electronic prototype development methods like the one that is proposed in this paper improve the tasks of design and modelling. Thus, a new weather station based on an Arduino platform has been developed to collect and store ambient temperature, relative humidity, barometric pressure, wind speed and air quality data, comparing the obtained data to those obtained using a validation station containing commercial sensors. The results show how the use of low cost Arduino sensors allow one to obtain similar values to those collected by more professional meteorological stations with insignificant scatter between both technologies.

Ensuring good indoor air quality in the spaces within educational centres is essential for the health and academic performance of students. In this sense, studying the evolution of health pollutants and their relationship with the environmental parameters of indoor humidity and temperature presents a challenge for the design of more efficient and comfortable buildings with a lower risk of virus infection. In this work, the relationship between pollution levels and SARS-CoV-2 virus infections in the academic year 2021/22 is shown, comparing the pollution values measured on-site with the value of the official measuring stations of the Community of Madrid. In addition, the impact of ventilation measures implemented during this period is assessed, aiming to establish guidelines for ensuring a safer and healthier school environment. It was found that during winter months, when there is less outdoor ventilation, pollution levels exceeded the recommended limits, according to reference regulations. This highlights the need for interior conditioning strategies in educational spaces. Thus, this multidimensional approach, considering both airborne pollutants and weather conditions, provides a comprehensive perspective on indoor air quality in school buildings in the central area of a metropolitan city, such as the Community of Madrid.

System based on piezoelectric sensors for deflection measurement in concrete beams

En la actualidad existe una amplia gama de sistemas y materiales que se emplean como atenuadores del ruido de impacto, ofreciendo buenas prestaciones a la hora de evitar la transmisión de vibraciones a través de los forjados. En este trabajo, se han elaborado placas de mortero de cuatro centímetros de espesor con cuatro tipos de árido diferentes combinados con distintas tipologías de aislamiento. Aprovechando la menor densidad de los morteros elaborados con árido reciclado, se ha llevado a cabo una investigación en la que se propone sustituir el 100% del árido natural por árido reciclado para la fabricación de morteros empleados en el sistema de losa flotante, ya que ofrecen una solución más eficiente desde el punto de vista acústico. Los morteros elaborados con áridos reciclados de cerámica y mixto los que presentan la solución óptima para atenuar impactos producidos sobre la superficie, reduciendo hasta en un 20% la velocidad de transmisión de impactos frente a sus homólogos elaborados con árido natural.

ResumenEl actual Código Técnico de la Edificación (CTE) pone de manifiesto la necesidad de cubrir parte de la demanda energética requerida para el abastecimiento de agua caliente sanitaria y climatización de piscinas cubiertas mediante sistemas de aprovechamiento de la energía solar térmica. En este artículo se presenta una comparativa entre las dos principales tipologías de captadores solares térmicos que existen en el mercado: el captador de placa plana y el captador de tubo de vacío, atendiendo a criterios de fracción solar, diseño e integración arquitectónica. Todo ello a fin de discernir en qué circunstancias es más favorable el uso de uno u otro sistema, comparando los resultados obtenidos mediante programas de simulación con la toma de medidas in situ.AbstractThe current Technical Building Code (CTE) highlights the need to cover part of the energy demand required for the supply of hot water and heating of indoor swimming pools using solar thermal systems. This article presents a comparison between the two main types of solar thermal collectors that exist in the market: the flat plate solar collector and the vacuum tube solar collector, according to criteria of solar fraction, design and architectural integration. All of this in order to discern in what circumstances the use of one or the other system is more favourable, comparing the results obtained through simulation programs with the taking of measurements in situ.