Protocolo de evaluación del impacto de la iluminación natural para gestión energética

El objetivo principal de este documento será establecer un protocolo que permita evaluar el impacto de la iluminación natural en los edificios, a través de la obtención de la tabla que contenga los valores horarios de los Factores de Iluminación Natural o Daylight Factor. Dicha tabla se obtendrá mediante el software Revit, siendo validada por los valores de DOE 2 para un edificio base. Conociendo el proceso a seguir, se realizarán diferentes aplicaciones, estudiando varios espacios pertenecientes a un edificio existente. Los resultados permitirán conocer el potencial de ahorro que tiene un edificio ante el uso de la iluminación natural, disminuyendo su consumo y aumentando su eficiencia energética. El documento está dividido en tres capítulos, siendo el primero una introducción sobre los conocimientos necesarios de iluminación, pasando posteriormente al desarrollo de la metodología que se debe llevar a cabo para realizar correctamente el protocolo y terminando con la aplicación en un edificio existente.The main objective of this document will be to establish a protocol that allows to evaluate the impact of natural lighting in buildings, by obtaining the table that contains the hourly values of the Natural Lighting Factors or Daylight Factor. Said table shall be obtained using the Revit software and validated by the values of DOE 2 for a base building. Knowing the process to follow, different applications will be carried out, studying several spaces belonging to an existing building. The results will allow us to know the potential savings that a building has due to the use of natural lighting, reducing its consumption and increasing its energy efficiency. The document is divided into three chapters, the first being an introduction on the necessary knowledge of lighting, going on to the development of the methodology to be carried out in order to correctly carry out the protocol and ending with the application in an existing building.Universidad de Sevilla. Grado en Ingeniería de la Energí

Fresnel solar cooling plant for buildings: Optimal operation of an absorption chiller through inverse modelling

Increasing comfort conditions in buildings imply higher energy demands. However, these needs can be mitigated by solar cooling solutions. These systems, such as absorption chillers, are complex and require stable operation, with strict control to maximise the solar fraction and minimise gas consumption. This is incompatible with the variability of renewable resources, so they are often coupled with auxiliary gas systems. Although gas-free operation is possible if these systems are optimally controlled, they would require special supervision. This paper aims to develop an experimental validation of an inverse model to manage an absorption chiller coupled with a solar cooling plant. To know its real behaviour, long-term experiments have been performed using this plant, which consists of a linear Fresnel solar collector and an auxiliary natural gas boiler. The inverse model is used as a predictive control tool to decide the auxiliary boiler commands of the absorption chiller to optimise its operation: maximum cooling production by minimising gas consumption and maximising solar contribution. It has been identified with data from two weeks and validated with data from one summer month. Results show that the model estimates, on a time base of fewer than 30 min, are acceptable with errors of less than 5%. In addition, the maximum error of the estimated seasonal COP and the renewable fraction are less than 6% per day. Therefore, the results prove the usefulness of the proposal as a predictive control for optimal operation. Furthermore, it could be used as a baseline for preventive maintenance. If the proposed model is used for optimal management of the absorption chiller, the thermal efficiency of the plant increases significantly, doubling the solar contribution. As a result, the gas consumption of the solar cooling plant is halved and the total cost of air conditioning the building decreases by 16%.Comisión Europea A_B.4.3_02

Adaptative Cover to Achieve Thermal Comfort in Open Spaces of Buildings: Experimental Assessment and Modelling

The global need for healthy and safe open spaces faces continuous temperature rise due to the heat island phenomenon and climate change. This problem requires new strategies for improving the habitability of open spaces (indoor and outdoor conditions in buildings). These techniques include reducing solar radiation, reducing the temperature of surrounding surfaces, and reducing the air temperature. The radiant solutions are essential for outdoor comfort, both in summer and in winter. They are easy to integrate into open spaces. This study explores a new concept of radiant solutions adapted for outdoor spaces. The solution was evaluated in a test cell to obtain its thermal behaviour in different operation conditions. Solutions were optimised for operating in a cooling regimen since it has been identified that the demands for comfort in open spaces in hot climates during the most severe summer months are more pronounced. Experimental results have allowed getting an inverse model to analyse the thermal behaviour of the solution. The inverse model achieved high precision in its estimations. Also, it facilitated knowing the radiant and convective effects. Only the radiant heat flux is relevant in open spaces with a low level of air confinement. Finally, the discussion describes the application of the proposed model. The model allows the replicability of the solution—creating new designs (integration) or evaluating into different operating conditions of the system. This discussion demonstrates the high level of knowledge acquired in the characterisation of the solution studied.e European Commission / European Regional Development Funds (ERDF) UIA03-301-CartujaQanat of Urban Innovative Action (UIA

Diseño innovador de chimenea solar para edificios: modelado y optimización

Conseguir los objetivos definidos por la Unión Europea en el horizonte 2030-250 y frenar los efectos del cambio climático, hacen esencial el empleo de técnicas de ahorro y eficiencia energética en todos los sectores económicos. El sector de la edificación comprende una gran parte del consumo mundial. Reducir la demanda energética de los edificios a través de técnicas pasivas que consigan aprovechar el potencial térmico del exterior, se convierte en la piedra angular de los movimientos actuales relacionados con el ahorro y la eficiencia energética. Unido a todo esto, se presenta la crisis sanitaria acutal provocada por el COVID-19, donde se ha puesto de manifiesto, más si cabe, la importancia de la calidad del aire en espacios interiores donde los habitantes de todo el mundo pasan la mayor parte de su tiempo. Así, el objetivo principal de este documento será el diseño y modelización de una técnica de ventilación pasiva consistente en una chimenea solar con capacidad de almacenamiento térmico durante el día y sistema de ventilación natural nocturna. Se optimiza la captación solar mediante el aumento del área de intercambio a través de la inclusión de aletas permitiendo aumentar el tiro generado en la chimenea. El documento incluye una primera parte de introducción, incluyendo el contexto actual, revisión de las estrategias de confort para interiores y se realiza una revisión de la literatura sobre chimenea solar. Se presenta el principio de funcionamiento general para las chimeneas solares, así como el diseño de la chimenea propuesta. Se presenta el modelo térmico en detalle, así como los resultados del análisis de sensibilidad para maximizar la componente solar y el estudio paramétrico para conocer la influencia de las distintas variables. Finalmente, se muestra el prototipo diseñado siguiendo el modelo térmico definido.Achieving the objectives defined by the European Union in the 2030-250 horizon and curbing the effects of climate change make the use of energy-saving and efficiency techniques essential in all economic sectors. The building sector comprises a large part of world consumption. Reducing the energy demand of buildings through passive techniques that manage to take advantage of the thermal potential of the exterior, becomes the cornerstone of current movements related to energy saving and efficiency. Together with all this, the current health crisis caused by COVID-19 is presented, where it has become evident, even more, if possible, the importance of air quality in indoor spaces where the inhabitants of the whole world spend most of it of his time. Thus, the main objective of this document will be the design and modeling of a passive ventilation technique consisting of a solar chimney with thermal storage capacity during the day and a natural ventilation system at night. Solar capture is optimized by increasing the exchange area through the inclusion of fins, allowing the draft generated in the chimney to be increased. The document includes the first part of the introduction, including the current context, a review of the comfort strategies for interiors, and a review of the literature on solar chimneys. The general operating principle for solar fireplaces is presented, as well as the proposed chimney design. The thermal model is presented in detail, as well as the results of the sensitivity analysis to maximize the solar component and the parametric study to know the influence of the different variables. Finally, the prototype designed following the defined thermal model is shown.Universidad de Sevilla. Máster en Sistemas de Energía Térmic

Effect of green infrastructures supported by adaptative solar shading systems on livability in open spaces

Lack of thermal comfort in the existing building stock in many warm summer climates and the COVID-19 pandemic have increased residents' temporary occupation of urban open spaces. However, climate change and other effects such as urban heat islands are also negatively affecting the livability of these spaces. Therefore, strategies are needed to improve the thermal conditions in these areas. In this context, the research designs, simulates and assesses an urban green infrastructure supported by an adaptative solar shading system. For this purpose, a public square to be renovated in Seville (Spain) is chosen. After an analysis of the current situation, more vegetation is added. However, trees are not planted fully grown, so their cover is not enough in the short term and an artificial system that protects from the sun by casting shade and that adapts to both their growth and the seasons is included. The urban space is characterized by on-site measurements, proposing four (initial, intermediates and final) scenarios using computational fluid dynamics simulations in an holistic microclimate modelling system. In turn, changes in thermal comfort are analyzed using the COMFA model. Results show that the air and surface temperature are decreased, reducing the number of hours in discomfort by 21% thanks to incorporating the green structure and by 30% due to the vegetation. It can be concluded that the use of these temporary urban prostheses enables urban spaces regenerated with vegetation to be enjoyed without waiting 20 or 30 years for the trees to mature, encouraging people to spend more time outdoors from the start of the intervention.19 página

Thermal Resilience of Citizens: Comparison between Thermal Sensation and Objective Estimation in Outdoor Spaces: A Case Study in Seville, Spain

Sanitary issues, combined with the effects of climate change, emphasize the comfort of outdoor spaces in cities. Numerous comfort models exist and can predict thermal sensation. However, these comfort indices need to be validated in hot zones and quantify the neutral range considering people’s thermal resilience. The present study investigates the outdoor thermal comfort of people who live in hot areas and are accustomed to this and quantifies this effect. For that, predictions provided by the COMFA thermal comfort model were compared with the occupants’ perceptions given in the field campaigns’ questionnaires. The field campaigns were associated with on-site monitoring of local climate variables. It was observed that during the survey period, the entire space was predicted to be uncomfortable by the COMFA model. On the contrary, the results of the questionnaires showed that the most frequently encountered thermal sensations were distributed between the comfort zone and the hot zone. The proposed methodology has been designed to be used by other researchers, and it is adaptable to other outdoor thermal comforts such as PET or ITS. The comparison between the model’s predictions and the users’ responses to space highlighted the tendency of the COMFA to overestimate the thermal sensations. This work’s results allow extending the neutral comfort band from 50 W/m2 (value of literature) to 80 W/m2. So, the paper quantifies that the effect of the thermal resilience of the people increases the thermal band of comfort by around 60%. These results will allow an accurate assessment of the effectiveness of future mitigation solutions implemented to improve outdoor thermal comfort in other world areas. It is due to the propose of a higher neutrality range researchers or designers could achieve outdoor thermal comfort in effective and reliable ways, even in hot climates

Thermal Resilience of Citizens: Comparison between Thermal Sensation and Objective Estimation in Outdoor Spaces: A Case Study in Seville, Spain

Sanitary issues, combined with the effects of climate change, emphasize the comfort of outdoor spaces in cities. Numerous comfort models exist and can predict thermal sensation. However, these comfort indices need to be validated in hot zones and quantify the neutral range considering people’s thermal resilience. The present study investigates the outdoor thermal comfort of people who live in hot areas and are accustomed to this and quantifies this effect. For that, predictions provided by the COMFA thermal comfort model were compared with the occupants’ perceptions given in the field campaigns’ questionnaires. The field campaigns were associated with on-site monitoring of local climate variables. It was observed that during the survey period, the entire space was predicted to be uncomfortable by the COMFA model. On the contrary, the results of the questionnaires showed that the most frequently encountered thermal sensations were distributed between the comfort zone and the hot zone. The proposed methodology has been designed to be used by other researchers, and it is adaptable to other outdoor thermal comforts such as PET or ITS. The comparison between the model’s predictions and the users’ responses to space highlighted the tendency of the COMFA to overestimate the thermal sensations. This work’s results allow extending the neutral comfort band from 50 W/m2 (value of literature) to 80 W/m2. So, the paper quantifies that the effect of the thermal resilience of the people increases the thermal band of comfort by around 60%. These results will allow an accurate assessment of the effectiveness of future mitigation solutions implemented to improve outdoor thermal comfort in other world areas. It is due to the propose of a higher neutrality range researchers or designers could achieve outdoor thermal comfort in effective and reliable ways, even in hot climates

Climatic Control of Urban Spaces Using Natural Cooling Techniques to Achieve Outdoor Thermal Comfort

The open spaces of cities have become hostile to citizens due to the high temperatures. Lack of thermal comfort hampers outdoor activities. It is imperative to combat these phenomena to bring life back to the streets and make spaces frequently used in the past more appealing to local citizens. The aim is to mitigate the severity of the outdoor climate to reach comfortable conditions in open spaces. For that, microclimate control based on natural cooling techniques is proposed to recover the habitability of these spaces of the cities. These techniques are characterised via experiments. Demostrando como es posible conseguir and integrated using simulation tools. Following this methodology, it is possible to design, size and define operation strategies for the ideal climate control system according to the type of need. This paper addresses a degraded and unused real space as a case study to demonstrate the feasibility of the methodology used. A system has been designed that stores water cooled at night by using the sky and night air and uses it during the day to produce cold air and cool cover. The experimental results test the efficiency of each solution that has been integrated into the complete system. The system operates every technology to keep the temperature radiant and the air of the occupants cool. For it, falling-film technology cools every night a volume of water below 18 °C and dissipation in a water pond by water sprinkler maintains a pond 10–15 °C below the outside air temperature. Also, results test how it is possible to guarantee thermal comfort conditions (operative temperature below of 28 °C) even when the environment surrounding the conditioned volume is at temperatures above 40 °C, and how the seismic allows maintaining these conditions during the worst summer hours. In conclusion, microclimate control allows for mitigating the severity of the outdoor climate to reach a degree of thermal comfort equivalent to that in enclosed venues

Extending the concept of high-performance buildings to existing dwellings

The ongoing energy crisis in Europe is highlighting the role of the building sector in energy consumption, particularly in countries like Spain, where 90.4% of existing dwellings lack thermal efficiency. Encouraging homeowners to undertake renovations can prove challenging, especially when complex thermal insulation techniques are involved. This study defines the optimal renovation package for six residential building models for 90% of southern Europe climates. Three methodologies were employed for optimal selection: a conventional cost-optimal approach, a method considering the impact of internal insulation on floor loss, and a CO₂ eq emissions approach based. The findings reveal that, on average, the primary energy demand of existing buildings can be reduced by 57%, with potential savings reaching up to 75% for a cost-optimal approach. Internal insulation significantly has a significant impact on floor loss costs, accounting for up to 60% of a building's life cycle cost, where the property value plays a significant role in the choice of insulation material, especially when considering the same thermal resistance. On the other hand, the CO₂ eq emission-based approach results in buildings with lower energy demand but more costly. Choosing the most suitable methodology for life cycle assessment requires a balance between economic constraints and environmental considerations

Thermal resilience of citizens: comparison between thermal sensation and objective estimation in outdoor spaces: a case study in Seville, Spain

Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).Sanitary issues, combined with the effects of climate change, emphasize the comfort of outdoor spaces in cities. Numerous comfort models exist and can predict thermal sensation. However, these comfort indices need to be validated in hot zones and quantify the neutral range considering people’s thermal resilience. The present study investigates the outdoor thermal comfort of people who live in hot areas and are accustomed to this and quantifies this effect. For that, predictions provided by the COMFA thermal comfort model were compared with the occupants’ perceptions given in the field campaigns’ questionnaires. The field campaigns were associated with on-site monitoring of local climate variables. It was observed that during the survey period, the entire space was predicted to be uncomfortable by the COMFA model. On the contrary, the results of the questionnaires showed that the most frequently encountered thermal sensations were distributed between the comfort zone and the hot zone. The proposed methodology has been designed to be used by other researchers, and it is adaptable to other outdoor thermal comforts such as PET or ITS. The comparison between the model’s predictions and the users’ responses to space highlighted the tendency of the COMFA to overestimate the thermal sensations. This work’s results allow extending the neutral comfort band from 50 W/m2 (value of literature) to 80 W/m2. So, the paper quantifies that the effect of the thermal resilience of the people increases the thermal band of comfort by around 60%. These results will allow an accurate assessment of the effectiveness of future mitigation solutions implemented to improve outdoor thermal comfort in other world areas. It is due to the propose of a higher neutrality range researchers or designers could achieve outdoor thermal comfort in effective and reliable ways, even in hot climates