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Achieving thermal comfort inside buildings in a region with a hot desert climate is challenging, especially in social housing, which is generally not designed or built suitably for these climates. Two well-known architectural strategies for reducing heat stress in these houses are thermal insulation and solar protection by shading. However, under free-running conditions, doubts arise about the effectiveness of these strategies. The social housing of the city of Hermosillo is exclusively single-family housing. The city has a hot desert climate with an average annual temperature of 25 ¿ and a mean oscillation of 15 ¿. During the hot season, there are recurring peaks above 48 ¿. This study aims to evaluate three low-cost architectural strategies to reduce heat stress in a single-family social house under free-running conditions; adding thermal insulation to walls and windows, adding sun protection to windows, and solar protection to the roof. The results show that both the use of thermal insulation and solar protections achieve improvements in the indoor thermal conditions of the house. However, when considering the warmer months, the solar protection strategies perform better in reducing indoor heat stress in terms of discomfort hours.

The study focused on low light intensity spaces. The research helps to find strategies for the reduction of energy consumption. It aims to highlight the role of colour temperature in the lighting design of historic buildings. The case study corresponds to a Roman archaeological site of the Badalona Museum in Barcelona. The lighting design uses three different colour temperatures to differentiate groups of surfaces which play a different role in the visual field. The information panels are lit with white light, the old Roman city has warm white colour light, and the new walkway over the ruins is lit with cool white light. This study evaluates colour temperature value, luminance value and visual task. The present work reveals that the colour temperature allows setting apart and classifying the visual information from low luminance values. The research presented addresses the importance of the colour temperature, as a significant visual perception component, in the inherent low light intensity design proposal to energy conservation.

The light metal roof is one of the roof typologies most used in low latitude regions with warm and humid climates. The low installation cost is one of the benefits of this typology, however, they offer only low resistance to the heat flux. In order to analyse strategies to reduce the indoor overheating in this climates, this investigation addresses the impact of reflectivity and emissivity on the light metal roof thermal behaviour. The study was carried out with dynamic simulations, considering the climate of a city in the south coast of Ecuador (Santa Rosa, 3°27′S). This analysis has parameterized the interior surface temperature in function of the reflectivity and emissivity, which has been validated with the measurements of several samples with different radiative properties. The analysed samples show that the effect of the aging and the use of different paints have a higher impact on the increase in emissivity than on reflectivity. In conclusion, the results show that the radiative parameter with the highest influence on interior surface temperature reduction is emissivity.

Terraces, as outdoor extensions of food and beverage businesses located in the public realm, have very high potential to activate the streetscape, bring people together and improving urban experiences. Among the consequences of the current COVID-19 pandemic are the recommendations of maximizing outdoor environments when conducting human interactions. Therefore, outdoor eating has dramatically increased throughout the world, with terraces becoming a radical urban change in many streetscapes. The urgency of the situation, and rapid implementation of these changes, has revealed some aspects of this phenomenon that should be considered when adapting the regulations to this new reality. However, the research on their functioning and impact is limited. Additionally, although energy consumption in the architectural and urban field is considered fundamental, research has rarely addressed small business outdoor spaces, placing the focus instead on residential heating or public lighting. This study focuses on the intersection of these two gaps by analyzing a set of terraces in Barcelona and estimating the power installed in their outdoor heating devices. The goal is to determine the potential energy consumed, contrast it with other values more commonly used when researching architectural energy consumption and point out the lack of sustainability of these approaches to providing comfort. The calculations show that the installed power in Barcelona terraces is significant and, when estimating potential consumption, it presents values higher that the average heating consumption of residential units in Spain. These results support two main conclusions: first, the relevance of addressing the means of providing comfort in outdoor urban spaces due to the high magnitude of their potential energy consumption, second, the importance of adapting those systems to outdoor conditions, understanding the needs of the occupants and the limitations of the environment in order to develop sustainable solutions that provide comfort without attempting to heat the air of the street.

Cities in the Mediterranean basin are characterised by compact and dense urban fabric, leading to a strong night-time urban heat island (UHI) intensity which increases thermal discomfort and building energy use in summer. This chapter reviews several experimental and numerical studies investigating the UHI intensity in representative Mediterranean cities, discussing the limitations and suitability of different approaches based on the purpose of the analysis (i.e. outdoor thermal comfort or building energy efficiency). Some recurrent urban climate characteristics are highlighted, such as the importance of urban morphology and sea breeze, the range of the daytime and night-time UHI intensity and its seasonal variability. Case studies of Rome and Barcelona are used to present modelling approaches to integrate urban climate in building energy performance. The complexity of the urban climate modifications in this context and their net energy impact on buildings are discussed considering UHI intensity, mutual shading between buildings, urban surface temperatures and wind speed in urban canyons. The last section is dedicated to urban and building design strategies for heat management in Mediterranean cities, including effective UHI mitigation measures and flexible passive cooling design strategies for buildings.

One of the main responsible for the heat flux between the exterior and the interior space is the building’s envelope. In order to achieve better interior thermal comfort conditions, it is necessary to control heat gains and losses through it. The aim of this paper is to analyze the role of the facade and the roof in a habitable volume exposed to the celestial vault and their energetic behavior due to the conductive and the radiative exchanges. A volume with no windows, no thermal insulation, no internal gains and with an approximate sky view factor (SVF) of 80% was used as the study case. The case study was modeled on a digital simulation program. Then it was calibrated and validated with measurements of indoor temperature and relative humidity taken on site for approximately three years. Heat flux values were obtained from the simulation program. With the envelope heat flux analysis, it can be concluded that the roof is the enclosure of the envelope that has the greatest influence on the heat flux balance, consequently also on the indoor temperature behavior.

In recent years, many software have appeared on the market to evaluate different parameters of lighting. Since the digital image has demonstrated the usefulness of measuring the luminances of surfaces, there are different software that help to evaluate the contrast of surfaces luminance. This paper presents the evaluation of three lighting software in three different lighting situations. Firstly, Aftab Alpha software requires the use of other sophisticated equipment such as luminance meter and reflex camera. Secondly, Fusion Optix software is an application easy to use because it works with a high dynamic range image from smartphones. Finally, Lumin software which reads the content of pixel-to-pixel picture to determine the luminance at each point of a scene is studied. Comparative measures serve to find the differences between the results of software analysis, the actual luminances of surfaces and different light intensities of spaces. This evaluation allows defining advantages and disadvantages of the use of three different software according to the light intensities of spaces. The study suggests that for spaces with low light intensity, the Aftab Alpha software and the Lumin software have a closer correspondence to the measurements. Concerning medium and high light intensity spaces, the Aftab Alpha software presents values near to reality.

El objetivo de este trabajo es analizar en corto tiempo y recursos propios, el comportamiento ambiental de los edificios del Multifamiliar, para extraer recomendaciones aplicables a las nuevas edificaciones de interés social que carecen de diseño bioclimático en clima cálido húmedo. La metodología se divide en cuatro etapas: 1 Realizar estudio del clima de Tampico de los años 1991 a 2010 del Sistema Meteorológico Nacional y del 2012 al 2013 de la estación meteorológica de la FADU-UAT. 2. Determinar las zonas de confort permisible, ventilación natural y necesidades de enfriamiento con aire acondicionado, con dos software Comfort Ex y Heliodon, y analizar con diagrama psicrométrico. 3. Evaluar los edificios, con estudio básico de sombras y ángulos solares en Heliodon. 4. Analizar las fachadas y vegetación de los edificios, con temperatura de superficie, arborización existente, velocidad y dirección del flujo de viento. Como conclusiones, el estudio evidencia los meses críticos de abril a octubre, la necesidad de protección solar en verano en todas las fachadas durante todo el día. La mejor orientación para un edificio es la Norte-Sur. Las fachadas más críticas son la Oeste, Noroeste y Suroeste. La separación entre los edificios permitió que el viento fluyera sin obstrucciones y se mantuvo con dirección Sureste durante todo el día a una velocidad de aire ligero por la mañana y durante la tarde aumentó su velocidad a brisa suave. Se recomienda utilizar vegetación en todas las fachadas para su protección solar, con copas amplias de más de 10 m de diámetro y mayores de 12 m de altura. L'objectiu d'aquest treball és analitzar en curt temps i recursos propis, el comportament ambiental dels edificis de l'multifamiliar, per extreure recomanacions aplicables a les noves edificacions d'interès social que no tenen disseny bioclimàtic en clima càlid humit. La metodologia es divideix en quatre etapes: 1 Realitzar estudi de el clima de Tampico dels anys 1991 a 2010 de el Sistema Meteorològic Nacional i de l'2012 a el 2013 de l'estació meteorològica de la FADU-UAT. 2. Determinar les zones de confort permissible, ventilació natural i necessitats de refredament amb aire condicionat, amb dos programari Comfort Ex i Heliodon, i analitzar amb diagrama psicromètric. 3. Avaluar els edificis, amb estudi bàsic d'ombres i angles solars en Heliodon. 4. Analitzar les façanes i vegetació dels edificis, amb temperatura de superfície, arborització existent, velocitat i direcció de l'flux de vent. Com a conclusions, l'estudi evidencia els mesos crítics d'abril a octubre, la necessitat de protecció solar a l'estiu a totes les façanes durant tot el dia. La millor orientació per a un edifici és la Nord-Sud. Les façanes més crítiques són la Oest, Nord-oest i Sud-oest. La separació entre els edificis permetre que el vent fluís sense obstruccions i es va mantenir amb direcció Sud-est durant tot el dia a una velocitat d'aire lleuger al matí i durant la tarda va augmentar la seva velocitat a brisa suau. Es recomana utilitzar vegetació en totes les façanes per a la seva protecció solar, amb copes àmplies de més de 10 m de diàmetre i majors de 12 m d'alçada. The objective of this work is the analysis in short time and with internal resources, of the environmental behavior of Multifamily buildings, to produce applicable recommendations for new social interest constructions lacking a bioclimatic design a warm humid weather. The methodology is divided into four: 1. The study of Tampico’s weather from 1991 to 2010 by the National Meteorological System and from 2012 to 2013 by the weather station at FADU-UAT. 2. The determination of areas of permissible comfort, natural ventilation and cooling AC needs, with software Comfort Ex and Heliodon and the examination with psychometric diagram. 3. The evaluation of the buildings, with basic shade and solar angle study in Heliodon. 4. The analysis of facades and vegetation of the buildings, with surface temperature, existing vegetation, wind speeds and the flow direction. Conclusions: The study demonstrates the critical months from April to October, the need of solar protection in summertime on all the facades through the entire day. The best orientation for a building is North-South. The most critical facades are West, Northwest and Southwest. Separation between buildings allowed the wind to flow without obstructions and remained directed to the Southeast the whole day at a light air speed during the morning, and during the afternoon, its speed increased to a soft breeze. It is recommended to use vegetation on all facades for their solar protection, with broad tree crowns with more than 10m in diameter and higher than 12m. A la Universidad Autónoma de Tamaulipas por el otorgamiento de la becaya las estudiantesde la Facultad de Arquitectura, Diseño y Urbanismo de la UAT Hillary Shaden Rodríguez Lerma y Rosa Patricia Torres Fajardo, por su colaboración

The overheating of the street surfaces has negative impacts on pedestrian comfort and cooling energy consumption. During the past few decades, extensive research has been carried out on heat mitigation technologies. However, there is limited knowledge on the efficacy of textile solar protections at the urban scale. In this paper, we investigate the cooling potential of sun sails on urban surfaces based on field measurements carried out in several streets of Cordoba (Spain). To this end, we develop a novel method based on time-lapse thermography at street level that allows for assessing the thermal behavior of urban scenes, in a comprehensive and agile way. Results show that high-mounted sun sails have a global cooling effect over the street, regardless of its orientation. Decreases due to sun sails in ground temperature reach up to 16¿C, and in façade temperature, up to 6¿C. Our observations demonstrate that sun sails can provide a heat mitigation efficacy similar to standard technologies while entailing softer levels of intervention. This work was supported by the Spanish Ministry of Education [grant number FPU-13/0388]

Opaque ventilated fa&ccedil, ades (OVFs) are increasingly gaining in importance in the design of sustainable buildings, given that they can lessen the building&acute, s environmental impact. Opaque ventilated fa&ccedil, ades can reduce thermal gains in hot climate zones, improving the thermal comfort indoors, and reducing air conditioning demand. Nevertheless, the thermal behaviour of the opaque ventilated fa&ccedil, ade depends on the climatic conditions and the building&acute, s specific design. This study analyses the effect of opaque ventilated fa&ccedil, ades in office buildings using 30 constructive configurations under eight tropical climate conditions. The study considers three options for the external layer of cladding (ceramic, stone, and aluminium composite material) and two configurations for the inner layer (plasterboard with mineral wool and ceramic). Simulations were carried out using the software tools TRanNsient SYstem Simulation program (TRNSYS) and TRNFlow. The model developed considers bioclimatic characteristics, including solar radiation and wind conditions for each climatic zone. The operating temperature was selected from within the range established by occupant comfort regulations. The findings suggest that it is possible to select the best office building opaque ventilated fa&ccedil, ade configuration for each of the specific climate conditions in Brazil.

The data contained in this article refers to the measurements of climatic factors during an entire year in low latitudes regions with warm and humid climates, in Santa Rosa city from Ecuador. Since the geographical location and the importance of cloudiness in these regions, these measurements have focused on the solar radiation flux, cloud cover and sky temperature. The data obtained have been configured in a weather file for energy calculations, which has been used in the research article “Assessment of the reflectivity and emissivity impact on light metal roofs thermal behaviour, in warm and humid climate” [1] .

Many urban studies have evaluated the impact of urban morphology on the microclimate of cities, and it has been shown that the influence is substantial. One of the significant impacts on outdoor thermal comfort in hot climate cities depends on solar radiation. The city of Jeddah is expected to start constructing a subway in 2020 that is likely to drastically change the behaviors of its inhabitants. Therefore, this study aims to investigate the relationship between modern and contemporary morphology and the potential of incident solar radiation to enhance pedestrian comfort by avoiding transit under this harsh solar radiation. The authors have evaluated the performance of two urban layouts, with different building densities to investigate the extent to which morphological features of the built environment can affect solar penetration on the streets. Moreover, the study assessed the influence of various built parameters such as street geometry (H/W ratio, streets orientations) and the solar indicator (Sky View Factor). Results show that in the low rise building layouts, the orientation of streets and the H/W ratio are not reliable. Moreover, it is difficult to reduce solar radiation penetration on the streets by modifying the morphology. Therefore, other ways should be tested to shade from solar penetration. Furthermore, the authors have observed that for high rise building layouts, pedestrian comfort could be modified through the adjacent morphology.

When we think about a dwelling’s thermal comfort, one of the first things that come to mind is to improve the envelope of the building, usually through the use of thermal insulation. However, in hot desert climate cities, where there is a great temperature oscillation, both daily and annually, the behavior of thermal insulation is not that clear. The city of Hermosillo follows a scattered pattern of urban growth. It has a hot desert climate, an annual mean temperature of 25 °C with an annual mean oscillation of 15 °C; during the summer season it presents extreme temperatures of 40–45 °C, annual precipitation of 387 mm and relative humidity of 43%. The most accepted architectonic strategies to improve the thermal behavior of buildings in hot desert climates are solar protection by shading, especially glazed surfaces, and the use of thermal insulation in the building’s envelope. This study aimed to assess the behavior of thermal insulation use in one storey dwellings. The results obtained show a reduction of energy loses through the envelope of the dwelling when more insulated, resulting in an interior thermal behavior not as favorable as was thought.

The causal relation among building typology and building energy demand is a complex balance of climate, morphology, technology and use. The assessment of the relation between mass of building elements and energy demand in different housing typologies is the main goal of this study. A novel indicator, namely the Buildingmass, is introduced and tested in the Mediterranean climate region. Explorations on nine conventional housing typologies in Barcelona and Rome are carried out. Buildingmass evaluation is based on the calculation of the mass of building elements. Energy demand is assessed by modelling on multi-space dynamic thermal analysis tool. Our results point out that the Buildingmass has a strong relevance on energy, playing an important role in reducing heating and cooling demand in the Mediterranean city, as described by the proposed correlation (R2 = 0.88). Moreover, this indicator gives a more detailed characterisation of the housing stock of the Mediterranean city. The study aims at bridging the gap between urban physics and urban metabolism studies and fostering energy conservation measures for the built environment.

Hoy en día, las ciudades en las que vivimos son sistemas complejos, que consumen energía y contaminan. Se han producido cambios radicales desde el siglo pasado como resultado de la introducción del automóvil y el auge del petróleo. Además, uno de los factores esenciales que influyen en el microclima es la morfología urbana. Las calles, como son una parte sustancial del espacio abierto urbano, juegan un papel importante en la creación del microclima urbano. La geometría y la orientación de las calles afectan la cantidad de radiación solar recibida por las superficies de las calles. El confort térmico al aire libre en las ciudades cálidas de clima desértico depende de la radiación solar. En condiciones de baja latitud, la minimización de la radiación solar dentro del entorno urbano a menudo puede ser un principio deseable en el diseño urbano, y el tejido urbano de las antiguas ciudades islámicas compactas lo refleja. Jeddah es una ciudad ubicada en la parte occidental de Arabia Saudita, en la latitud 21 ° 32 'norte. Se espera que la ciudad comience a construir un metro en 2020. Por lo tanto, es probable que eso cambie drásticamente el comportamiento de sus habitantes.Este estudio tiene como objetivo extraer conceptos de la antigua área compacta para desarrollar una morfología compacta estratégica futura sobresaliente que facilitaría el desarrollo dinámico de la ciudad. Considerar las estaciones principales del futuro metro como nodos que crean una tela más densamente habitada alrededor de ellas proporcionaría espacios de transición para actividades peatonales. El concepto es proporcionar un "efecto oasis", atribuido principalmente al sombreado. El microclima generado dentro y alrededor de estos nodos de actividad debe estar principalmente bien diseñado para alentar a los residentes y visitantes a reclamar una vida peatonal que era notable en la ciudad vieja, pero que prácticamente ha desaparecido en vecindarios más nuevos, totalmente dedicada al transporte de automóviles. Los servicios e instalaciones alrededor de los nodos de metro deberían convertirse en las áreas de confort térmico de transición de las salidas de la estación de metro.El documento proporciona una visión general de la morfología de las antiguas ciudades islámicas ubicadas a bajas altitudes. Evalúa las características del antiguo tejido urbano de la ciudad de Jeddah a través del análisis gráfico de la geometría de la calle, las orientaciones y el cálculo de la densidad acumulada. Se han calculado cuatro indicadores de densidad diferentes (FSI), (GSI), (L) y (OSR). Además, las simulaciones que se utilizan para evaluar la radiación solar incidente en el diseño urbano antiguo mediante el software "Heliodon 2" (onda corta directa, Sky View Factor) "Heliodon plus" (datos climáticos), describen la distribución cuantitativa de la radiación incidente en el cañón y fachadas que nos permiten identificar aspectos específicos.Los hallazgos ilustran las implicaciones del diseño anterior. Muestra que la morfología existente socava significativamente la intensidad de la energía solar y el intervalo de tiempo de acceso solar en verano e invierno en las superficies horizontales (cañones) y las superficies verticales (paredes). Los resultados proporcionan algunas ideas útiles para la planificación de un 'efecto Oasis' de alta densidad y compacto alrededor de los nodos metropolitanos. Avui dia, les ciutats en què vivim són sistemes complexos, que consumeixen energia i contaminen. S'han produït canvis radicals des del segle passat com a resultat de la introducció de l'automòbil i l'auge del petroli. A més, un dels factors essencials que influeixen en el microclima és la morfologia urbana. Els carrers, com són una part substancial de l'espai obert urbà, juguen un paper important en la creació del microclima urbà. La geometria i l'orientació dels carrers afecten la quantitat de radiació solar rebuda per les superfícies dels carrers. El confort tèrmic a l'aire lliure a les ciutats càlides de clima desèrtic depèn de la radiació solar. En condicions de baixa latitud, la minimització de la radiació solar dins de l'entorn urbà sovint pot ser un principi desitjable en el disseny urbà, i el teixit urbà de les antigues ciutats islàmiques compactes ho reflecteix. Jeddah és una ciutat situada a la part occidental d'Aràbia Saudita, a la latitud 21 ° 32 'nord. S'espera que la ciutat comenci a construir un metro a 2020. Per tant, és probable que això canviï dràsticament el comportament dels seus habitants.Aquest estudi té com a objectiu extreure conceptes de l'antiga àrea compacta per desenvolupar una morfologia compacta estratègica futura excel·lent que facilitaria el desenvolupament dinàmic de la ciutat. Considerar les estacions principals de el futur metro com nodes que creen una tela més densament habitada al voltant d'elles proporcionaria espais de transició per a activitats de vianants. El concepte és proporcionar un "efecte oasi", atribuït principalment a l'ombrejat. El microclima generat dins i al voltant d'aquests nodes d'activitat ha d'estar principalment ben dissenyat per encoratjar als residents i visitants a reclamar una vida vianants que era notable a la ciutat vella, però que pràcticament ha desaparegut en veïnats més nous, totalment dedicada al transport d'automòbils. Els serveis i instal·lacions voltant dels nodes de metro s'haurien de convertir en les àrees de confort tèrmic de transició de les sortides de l'estació de metro.El document proporciona una visió general de la morfologia de les antigues ciutats islàmiques situades a baixes altituds. Avalua les característiques de l'antic teixit urbà de la ciutat de Jeddah a través d'l'anàlisi gràfica de la geometria del carrer, les orientacions i el càlcul de la densitat acumulada. S'han calculat quatre indicadors de densitat diferents (FSI), (GSI), (L) i (OSR). A més, les simulacions que s'utilitzen per avaluar la radiació solar incident en el disseny urbà antic mitjançant el programari "Heliodon 2" (ona curta directa, Sky View Factor) "Heliodon plus" (dades climàtiques), descriuen la distribució quantitativa de la radiació incident en el canó i façanes que ens permeten identificar aspectes específics.Les troballes il·lustren les implicacions de el disseny anterior. Mostra que la morfologia existent soscava significativament la intensitat de l'energia solar i l'interval de temps d'accés solar a l'estiu i hivern en les superfícies horitzontals (canons) i les superfícies verticals (parets). Els resultats proporcionen algunes idees útils per a la planificació d'un 'efecte Oasis' d'alta densitat i compacte al voltant dels nodes metropolitans. Nowadays, the cities in which we are living are complex, energy-consuming, and polluting systems. Radical changes since the last century have happened as a result of the automobile introduction and the oil boom. Moreover, one of the essential factors that influence microclimate is urban morphology. Streets, as they are a substantial part of urban open space, play a significant role in creating the urban microclimate. Street geometry and orientation affect the amount of solar radiation received by street surfaces. Outdoor thermal comfort in hot desert-climate cities depends on solar radiation. Under low latitude conditions, the minimization of solar radiation within the urban environment may often be a desirable principle in urban design, and the urban fabric of old compact Islamic cities reflects that. Jeddah is a city located in the western part of Saudi Arabia, at latitude 21° 32' north. The city is expected to start constructing a subway in 2020. Therefore, that is likely to change the behaviors of its inhabitants drastically.This study aims to extract concepts from the old compact area to develop an outstanding future strategic compact morphology that would facilitate the dynamic development of the city. Considering the main stations of the future metro as nodes creating more densely inhabited fabric around them would provide transitional spaces for pedestrian activities. The concept is to provide an 'oasis effect,' mainly attributed to shading. Microclimate generated in and around these activity nodes must be mainly well designed to encourage residents and visitors to reclaim a pedestrian life that was noticeable in the old city, but has virtually disappeared in newer neighborhoods, entirely devoted to automobile transport. Services and facilities around metro nodes should become the transitional thermal comfort areas of the metro station exits.The paper provides an overview of the old Islamic cities' morphology located at low altitudes. It evaluates the characteristics of the old urban fabric of Jeddah city through graphical analysis of the street geometry, orientations, and calculating the built-up density. Four different density indicators have been calculated (FSI), (GSI), (L), and (OSR). Furthermore, simulations that are used to assess the incident solar radiation in the old urban layout by the software "Heliodon 2" (direct shortwave, Sky View Factor) "Heliodon plus" (climatic data), describe the quantitative distribution of incident radiation on the canyon and facades enabling us to identify specific aspects.The findings illustrate the implications of the old layout. It shows that the existing morphology significantly undermines the intensity of solar energy and solar access time interval in summer and winter on the horizontal surfaces (canyons) and vertical surfaces (walls). The results provide some helpful insights for the planning of a high density and compact 'Oasis effect' around the metro nodes. The authors thank the Spanish Ministry of Education for supporting this work under project code: BIA2016-77675-R. And special thanks to the Ministry of Education of the Kingdom of Saudi Arabia for supporting and funding this work.

Urban heat island effect is almost always neglected in building energy simulations, due to difficulties in obtaining site-specific climate data with a district-scale resolution. This study aims at filling this gap for the Mediterranean urban context, presenting a set of tools to estimate the climatic performance of urban fabric at the local scale. The results are based on climatic analysis conducted in Rome (Italy) and Barcelona (Spain) with the Urban Weather Generator (UWG) model, validated using temperature measurements taken in urban meteorological stations. Parametric analysis of the UHI intensity was performed considering five key variables: urban morphology, vegetation cover, anthropogenic heat from buildings, anthropogenic heat from traffic and albedo. The results show that the variability of urban morphology has the major impact on urban temperature. Two robust relationships between three morphology descriptors of urban fabric and UHI intensity were established applying multiple regression analysis. Such relationships indicate that both the horizontal and the vertical density of buildings play a major role on the temperature increase in urban areas. Easy-to-use graphical tools have been provided to compare the climate performance of different urban textures and to estimate the average UHI intensity variability in Mediterranean cities.

In this chapter, vernacular roofs are analyzed to learn the principles which define their performance. Unfortunately, many examples of this typology have disappeared, due to its fragility in front of weather conditions and their state of neglect; vernacular roofs are strongly linked to place and local resources, which are perishable. Despite this, they have fulfilled successfully their function, adapted to climate, for centuries. However, many changes in architecture design and materials changed the appearance and composition of roofs in the last century. It led to a design of roofs as a series of specialized layers with differentiated functions which perform better in some aspects but present some environmental disadvantages. Contemporary roof design can learn from former experiences, not with the purpose of returning to a vernacular language but getting back to their basic principles.

Las características del entorno urbano construido influyen en el comportamiento y en el bienestar de los usuarios. En las ciudades del entorno mediterráneo, con clima templado, las condiciones ambientales son favorables al bienestar del peatón, pero no siempre son suficientes ni homogéneas en todas las calles de un mismo distrito. Hay diferencias claramente perceptibles que hacen que un peatón describa rutas, en sus recorridos diarios, que no siempre son las más cortas o las más eficientes. Las herramientas de análisis urbano que aportan datos fiables y medibles de estas características se han convertido en un recurso útil para la comunidad científica de este ámbito y para los foros donde se centra la toma de decisiones sobre política urbana a pequeña o a gran escala. En este trabajo se ha tomado como base una de estas herramientas, el Transit Orientated Development Standard (TOD Standard), un instrumento de puntuación definido por el Institute for Transportation and Development Policy (ITDP), para evaluar un total de 12 áreas urbanas de las ciudades de Roma y Barcelona. El trabajo pone en evidencia que la representación gráfica de unos valores en un mapa aporta información complementaria muy importante y que no aparece en la simple cuantificación numérica. La representación de datos geográficamente localizada añade información contextual a los valores numéricos y, convenientemente ajustada en sus valores y escala, permite evaluar la calidad del espacio urbano a pequeña escala. Los criterios que fueron establecidos para tipologías urbanas propias de ciudades dispersas, cuando se han aplicado a ciudades con una morfología compacta requieren un ajuste a esa realidad y sugieren cualidades que no se ven en las tablas de valores. Se pone en evidencia que la representación en el mapa es la mejor manera de leer, sobre el plano, qué puede hacer que unas calles sean más transitadas que otras. Este trabajo demuestra que situar en el mapa los datos de puntuación del TOD completa la información y permite interpretar cualidades de la vida urbana fundamentales para fomentar la movilidad a pie. Tener en cuenta datos cualitativos, además de los cuantitativos, puede ser decisivo para asegurar el éxito de proyectos urbanos que tengan como objetivo fomentar los trayectos peatonales como sistema de movilidad prioritario. Les característiques de l'entorn urbà construït influeixen en el comportament i en el benestar dels usuaris. A les ciutats de l'entorn mediterrani, amb clima temperat, les condicions ambientals són favorables a el benestar del vianant, però no sempre són suficients ni homogènies en tots els carrers d'un mateix districte. Hi ha diferències clarament perceptibles que fan que un vianant descrigui rutes, en els seus recorreguts diaris, que no sempre són les més curtes o les més eficients. Les eines d'anàlisi urbà que aporten dades fiables i mesurables d'aquestes característiques s'han convertit en un recurs útil per a la comunitat científica d'aquest àmbit i per als fòrums on es centra la presa de decisions sobre política urbana a petita o a gran escala. En aquest treball s'ha pres com a base una d'aquestes eines, el Transit Orientated Development Standard (TOD Standard), un instrument de puntuació definit per l'Institute for Transportation and Development Policy (ITDP), per avaluar un total de 12 àrees urbanes de les ciutats de Roma i Barcelona. El treball posa en evidència que la representació gràfica d'uns valors en un mapa aporta informació complementària molt important i que no apareix en la simple quantificació numèrica. La representació de dades geogràficament localitzada afegeix informació contextual als valors numèrics i, convenientment ajustada en els seus valors i escala, permet avaluar la qualitat de l'espai urbà a petita escala. Els criteris que van ser establerts per tipologies urbanes pròpies de ciutats disperses, quan s'han aplicat a ciutats amb una morfologia compacta requereixen un ajust a aquesta realitat i suggereixen qualitats que no es veuen en les taules de valors. Es posa en evidència que la representació en el mapa és la millor manera de llegir, sobre el pla, què pot fer que uns carrers siguin més transitades que d'altres. Aquest treball demostra que situar al mapa les dades de puntuació del TOD completa la informació i permet interpretar qualitats de la vida urbana fonamentals per a fomentar la mobilitat a peu. Tenir en compte dades qualitatives, a més dels quantitatius, pot ser decisiu per assegurar l'èxit de projectes urbans que tinguin com a objectiu fomentar els trajectes de vianants com a sistema de mobilitat prioritari. The characteristics of the built urban environment influence the behaviour and well-being of the users. In the Mediterranean cities, with mild climate, the environmental conditions are favourable to the well-being of the pedestrian. However, they are not always homogeneous in all the streets of the same district. There are perceptible differences that cause that pedestrians take some routes, in their daily journeys that are not always the shortest ones or the most efficient. Urban analysis tools that provide reliable and measurable data of these characteristics have become a useful resource for the scientific community in this area and for forums where decision-making is focused on urban policy on a small or large scale. In this work, one of these tools, the Transit Orientated Development Standard (TOD Standard), a scoring instrument defined by the Institute for Transportation and Development Policy (ITDP), has been taken as a basis for evaluating a total of 12 urban areas of the Cities of Rome and Barcelona. The work shows that the graphical representation of some values on a map provides very important complementary information that does not appear in the simple numerical quantification. The geographically located data representation adds contextual information to the numerical values. Conveniently adjusted in their values and scale, it allows evaluating the quality of the urban space on a small scale. When applying the criteria established for urban typologies typical of sprawl cities to cities with a compact morphology, an adjustment to that reality is required. They also suggest qualities that are not seen in the tables of values. It is revealed that map representation is the best way to understand what can make some streets busier than other streets. This work demonstrates that placing the TOD scoring data on the map completes the information and allows interpreting qualities of urban life that are essential for promoting mobility on foot. Taking into account qualitative data, in addition to quantitative data, can be decisive to ensure the success of urban projects that aim to promote pedestrian paths as a priority mobility system. Este trabajo se ha desarrollado en el marco del proyecto de investigación BIA2016-77675-R financiado por el Gobierno de España. En la toma de datos han participado los estudiantes del MBArch de la línea AiE (UPC) del curso 18-19, así como los participantes al 5th International Workshop on Mediterranean Urban Morphology llevado a cabo en SOS Urban Lab (Sapienza Università di Roma) en mayo de 2019.

La ciudad es un sistema complejo en el que confluyen muchos parámetros que dificultan sobremanera un análisis preciso de todos ellos y, en consecuencia, la valoración de los fenómenos que se producen y sus repercusiones en el medio ambiente. La planificación urbana es uno de los retos ante los que se encuentra la sociedad actual, implicando tanto a arquitectos y urbanistas como a otros colectivos muy diversos que convergen en este espacio común de intercambio energético y ecológico.La población mundial se está desplazando hacia las áreas urbanas en proporción cada vez mayor, por lo que estos son posibles puntos de conflicto y oportunidad en los que es necesario actuar y planificar de forma cuidadosa. Para optimizar la planificación urbana, será fundamental disponer de un cuerpo de doctrina en temas ambientales y sociales que tengan en cuenta aspectos de consumo energético y de recursos, así como de confort y bienestar personal.En este contexto nace el proyecto de investigación “MUM-Fundamentos para la Caracterización de la Morfología Urbana Mediterránea”. Este proyecto avanza en la mejora de la eficiencia energética en ciudades mediterráneas, identificando parámetros morfológicos de los edificios, en tanto que configuradores de ciudades, que permiten caracterizar distintas tramas urbanas y su influencia en la demanda energética.Actualmente no existe una parametrización de las estructuras urbanas que permita simular su comportamiento ambiental de forma razonable. Esta investigación ha identificado y definido parámetros urbanos necesarios para esta caracterización geométrica de las distintas tramas que facilitarían una aproximación al comportamiento ambiental. The city is a very complex system in which many parameters converge. The large number of these parameters greatly hinders not only an accurate analysis of all of them, but also the assessment of the phenomena that occur in the city and its impact on the environment. Urban planning is one of the challenges that society faces today, involving architects, planners and other social and professional stakeholders. All of them converge in a common field of energetic and ecological exchange. The world’s population is moving towards urban areas in an increasing proportion. Consequently, these areas are becoming potential points of conflict and opportunities and, therefore, must be carefully planned. To optimize urban planning, it is essential to have a body of doctrine in both environmental and social issues, considering subjects such as energy and resources consumption, comfort and well-being. In this context, the investigation project “MUM- Identification of Parameters Involved in Architectural Energy Efficiency is originated. This project aims to improve energy efficiency in buildings of Mediterranean cities by identifying those parameters of buildings morphology that allow to describe different urban tissues and their influence on energy demand. Nowadays, there is a lack of urban structures parametrization systems that allow to simulate their behaviour accurately. This investigation aims to identify and define urban parameters required for a geometric description of the different urban fabrics, in order to ease an approach to environmental performance assessment. La ciutat és un sistema complex en el qual conflueixen molts paràmetres que dificulten en gran manera una anàlisi precís de tots ells i, en conseqüència, la valoració dels fenòmens que es produeixen i les seves repercussions en el medi ambient. La planificació urbana és un dels reptes davant els quals es troba la societat actual, implicant tant a arquitectes i urbanistes com a altres col·lectius molt diversos que convergeixen en aquest espai comú d'intercanvi energètic i ecològic. La població mundial s'està desplaçant cap a les àrees urbanes en proporció cada vegada més gran, de manera que aquests són possibles punts de conflicte i oportunitat en els quals cal actuar i planificar de forma acurada. Per optimitzar la planificació urbana, serà fonamental disposar d'un cos de doctrina en temes ambientals i socials que tinguin en compte aspectes de consum energètic i de recursos, així com de confort i benestar personal. En aquest context neix el projecte d'investigació "MUM-Fonaments per a la Caracterització de la Morfologia Urbana Mediterrània". Aquest projecte avança en la millora de l'eficiència energètica en ciutats mediterrànies, identificant paràmetres morfològics dels edificis, com a configuradors de ciutats, que permeten caracteritzar diferents trames urbanes i la seva influència en la demanda energètica. Actualment no existeix una parametrització de les estructures urbanes que permeti simular el seu comportament ambiental de manera raonable. Aquesta investigació ha identificat i definit paràmetres urbans necessaris per a aquesta caracterització geomètrica de les diferents trames que facilitarien una aproximació al comportament ambiental.

In March 1995, the ITER (Instituto Tecnologico y de Energias Renovables), along with the Excellent Island Government of Tenerife (Cabildo Insular de Tenerife), launched an international competition for 25 bioclimatic dwellings to be built in Tenerife, Canary Islands, homologated by the International Union of Architects (UIA). The International Tender counted on the College of Architects of the Canary Islands to organize a call for preliminary projects of 25 one-family dwellings located in an area within the Wind Park of Tenerife, near the sea, at the south-east of the island (Fig. 9.1). The inception of the competition can be traced back to 1995, in the Summit of the Earth in Rio de Janeiro (1992). One of the key points of this meeting was to make a statement concerning the protection of the environment (General Assembly of the United Nations 2012). Consequently, the projects in Tenerife were to be designed following bioclimatic principles adapted to the climatic conditions (Lopez de Asiain 2001) of the island’s seaside environment. Moreover, the integration of recycled and recyclable materials was encouraged, as well as the use of renewable energy systems.

Within the variation of energy performance at urban scale, the relation between solar irradiation and urban form takes a central role. The solar availability on facades which is influenced by the morphology of the urban context, is strictly related to building energy performance indeed. In this paper, we aim at identifying a set of urban morphology indicators (UMIs) that show the most accurate relations with the solar availability on facades (SIy) in the Mediterranean context. The analysis that relates to 14 urban textures of Rome and Barcelona comprises seven UMIs: gross space index, floor space index, facade-to-site ratio, average building height, volume-area ratio, building aspect ratio and sky factor of building facades. The SIy in each texture has been calculated with Heliodon2 software, using normalised models; the relation between SIy and UMIs were investigated using least-square regression analysis. Results suggest that gross space index, facade-to-site ratio and sky factor show very good correlation with SIy (R2 = 0,91) and could be used to develop a comparative assessment tool of solar performance at fabric scale. This could ease the work of urban planners and architects in the early stage of design, reducing both data and time normally needed to perform solar analyses at urban scale.

The Urban Heat Island (UHI) effect is particularly concerning in Mediterranean zone, as climate change and UHI scenarios foresee a fast growth of energy consumption for next years, due to the widespread of air conditioning systems and the increase of cooling demand. The UHI intensity is thus a key variable for the prediction of energy needs in urban areas. This study investigates the intensity of UHI in Barcelona (Spain), the densest Mediterranean coastal city, and its impact on cooling demand of residential buildings. The experimental analysis is based on temperature data from rural and urban Weather Stations and field measurements at street level. The maximum average UHI intensity is found to be 2.8 °C in winter and 1.7 °C in summer, reaching 4.3 °C at street level. Simulations performed with EnergyPlus indicate that the UHI intensity increases the sensible cooling load of residential buildings by around 18%–28%, depending on UHI intensity, amount of solar gains and cooling set point. In the light of the results, the UHI intensity in Mediterranean context should be properly considered in performing energy evaluations for urban contexts, since standard meteorological data from airport weather stations are not found to be accurate enough.

Visual environment in Mediterranean countries is full of contrasts. The vertical position of the sun as well as the frequent clear sky condition shape an urban environment defined by surfaces flooded by the sun and in the shade, which causes a high contrast, also between interior and exterior spaces. It is paradoxical that, in latitudes where the amount of natural light available is clearly over demand, the design of interior lighting has to cope with this situation using high levels of artificial light. If sustainable criteria are aimed to be introduced in lighting design, it is important to know the lit environment outside and the contrast with the interior of the building. With this aim, an analysis implemented in a specific case of study was outlined. The results highlight the existing contrast between inside and outside in a specific Mediterranean urban environment, and lay the foundations for further studies.

Today, the building sector is one of the greatest energy consumers of the world. Therefore, it is important that designers think about strategies to save energy at the different stages of the building process, including during its life. Considering that a great deal of energy will be spent in artificial lighting, an improvement in the performance in front of light of the architecture itself could lead to a better vision of the spaces, which depends on the quantity and quality of light available and on the architectural characteristics as well. One of the most influential aspects is the colour of the space. Here, a case study is presented in which three coloured spaces were assessed by observers under different lighting conditions. Luminance and illuminance measurements were taken to compare these values with the votes given. The results query the correlation between measured values and luminosity of three-dimensional spaces. As a consequence, the choice of a particular colour may increase the sensation of light in a space and, therefore, a reduction of energy use in artificial lighting is possible. In addition, architectural design can take advantage of colour to improve the visual quality of indoor spaces.

The construction of high-rise buildings has always been where the newest technological advances were displayed for the first time.

The correlation between air and surface temperatures is recurrently used as a descriptor of the urban climate within built environments. The aim of this paper is to explore the possibilities of time-lapse thermography to visualize this relationship in time and space. To this end, thermograms are colorized using a relative-to-air temperature scale, instead of the usual absolute one. This approach was tested for two deep urban canyons belonging to cities with different climates. Relative-to-air thermography has two main advantages: it facilitates comparisons between the thermal responses of urban scenes under different climates and makes convective energy exchanges more comprehensive.

Following years of research and design in architecture under bio-climatic, sustainable and passive-energy concepts, today’s buildings are often well designed and constructed, responding to determined climate conditions and the user’s requirements for comfort and, in some cases, they are integrated into the urban environment. However, the lifetime of a building can be over 100 years and the climate is changing rapidly. This work investigates the impact of climate change future (2040 and 2070) on the energy consumption of residential buildings recently constructed, under three possible scenarios. The scenarios are created considering a low, medium or strong effect of global warming. Two types of buildings, with comparable consumption results of today, are investigated in three different cities around the world with a multi-zone type 56 of Trnsys simulation tool. At the end of the work, the concepts of energy robustness and global thermal effusivity of buildings are discussed as important strategies to reduce the possible impact of climate change on the built environment. The use of simulation tools to estimate the sensitivity of buildings is also analyzed, taking into consideration the recent goals of applying uncertainty and sensitivity analysis to building performance simulation science.

The urban canyon model has been recurrently used as a basis for many solar access studies. However, its conception as endless structures disregards the effect of street intersections, despite being characteristic elements of urban fabrics. This paper aims to evaluate the impact of street discontinuities on solar access over building façades. The potential of crossings to increase the available radiation has been assessed through computer simulations in dense urban environments in a Mediterranean location. For the cases studied, results show that local effects of an intersection almost disappear beyond a speci¿c distance for each aspect ratio, which can be helpful to determine the suitable level of detail for solar analyses at an urban fabric scale.

The appearance of the city is strongly linked to many aspects such as climate, culture and sociological background. In cities with a prevalence of clear skies, one of the determining aspects is the climatic condition, which defines a luminous context where all elements appear significantly bright. In order to establish the luminosity of the urban scene and its components, an analysis of pictures taken in real environments is proposed, carried out through a digital image processing software developed by the authors. The information contained in each pixel of a digital image is used to assess the distribution of light in the picture. The pictures selected for assessment represent an urban scene as seen by a standing observer. In this situation the scene can be divided in three zones with similar features: pavement, sky and façades. The developed software provides output information for the aforementioned zones and the whole image consisting on light data (average, maximum, minimum and standard deviation) convertible to luminance (cd/m2) if reference values are provided. The validity of the procedure is tested in this work and implemented in real pictures. After testing it, the software has proven to be easy to use and the results obtained in the examples have shown a trend in their values. The implementation of the software suggests that a wider number of cases of study would make possible to establish a pattern in the daylight distribution of urban scenes conceived as an addition of zones with different luminous appearance. La apariencia de la ciudad está fuertemente ligada a muchos aspectos como el clima, la cultura y el trasfondo sociológico. En las ciudades con una prevalencia de cielo despejado, uno de los aspectos determinantes es la condición climática, que define un contexto luminoso donde todos los elementos aparecen significativamente brillantes. Para establecer la luminosidad de la escena urbana y sus componentes se propone un análisis de imágenes tomadas en entornos reales, realizado a través de un software de procesamiento digital de imágenes desarrollado por los autores. La información contenida en cada píxel de una imagen digital se utiliza para evaluar la distribución de luz en la imagen. Las imágenes seleccionadas para la evaluación representan una escena urbana vista por un observador permanente. En esta situación la escena se puede dividir en tres zonas con características similares: pavimento, cielo y fachadas. El software desarrollado proporciona información de salida para las zonas antes mencionadas y toda la imagen consiste en datos de luz (promedio, máximo, mínimo y desviación estándar) convertibles en luminancia (cd/m2) si se proporcionan valores de referencia. La validez del procedimiento se prueba en este trabajo y se implementa en imágenes reales. Después de probarlo, el software ha demostrado ser fácil de usar y los resultados obtenidos en los ejemplos han mostrado una tendencia en sus valores. La implementación del software sugiere que un mayor número de casos de estudio haría posible establecer un patrón en la distribución diurna de escenas urbanas concebidas como una adición de zonas con diferente aspecto luminoso. L'aparença de la ciutat està fortament lligada a molts aspectes com el clima, la cultura i el rerefons sociològic. A les ciutats amb una prevalença de cel clar, un dels aspectes determinants és la condició climàtica, que defineix un context lluminós on tots els elements apareixen significativament brillants. Per establir la lluminositat de l'escena urbana i els seus components es proposa una anàlisi d'imatges preses en entorns reals, realitzat a través d'un programari de processament digital d'imatges desenvolupat pels autors. La informació continguda en cada píxel d'una imatge digital s'utilitza per avaluar la distribució de llum a la imatge. Les imatges seleccionades per a l'avaluació representen una escena urbana vista per un observador permanent. En aquesta situació l'escena es pot dividir en tres zones amb característiques similars: paviment, cel i façanes. El programari desenvolupat proporciona informació de sortida per a les zones abans esmentades i tota la imatge consisteix en dades de llum (mitjana, màxim, mínim i desviació estàndard) convertibles en luminància (cd/m2) si es proporcionen valors de referència. La validesa del procediment es prova en aquest treball i s'implementa en imatges reals. Després de provar-ho, el programari ha demostrat ser fàcil d'usar i els resultats obtinguts en els exemples han mostrat una tendència en els seus valors. La implementació del programari suggereix que un major nombre de casos d'estudi faria possible establir un patró en la distribució diürna d'escenes urbanes concebudes com una addició de zones amb diferent aspecte lluminós.

Energy is considered as a main influence on urban configurations. However, there is a difficulty on translating the city models based on theoretical renewable energy concepts into practical applications. This study considers the possibility of understanding this future model as a transformation of the existing urban centres. With this objective, a methodology to intervene in existing cities based on the study of solar access is developed. Therefore, an analysis of solar potential in relation with urban morphology is carried on through a simulation software in l’Eixample, a neighbourhood of Barcelona. The distribution of the sun factor in the different areas of the building blocks envelope displays possible morphological modifications that would facilitate solar energy collection. Consequently, the analytical method presented could be applied to regulate urban interventions with the aim of obtaining more solar energy based cities.

Natural resources such as daylight and sunlight are highly appreciated in countries with prevailing overcast skies. Taking advantage of this scarce resource contributes to saving energy on artificial lighting. In contrast to northern, southern European cities are distinguished by a large number of days with direct sunlight caused by a propitious climate condition. While it is a positive issue in terms of energy availability, the abundance of it can be counterproductive if management measures are not taken. Apart from the thermal consequences, lighting penetration into buildings causes a great contrast between inside and outside. This is especially critical when the visual system does not have enough time to adapt, as happens at entrance areas. The aim of this study is to analyze the light contrast between these areas and the urban outside in sunny conditions. To attain this objective, light data from five entrance spaces and their contiguous streets were analyzed and measured. The results were divided into three zones in the visual scene, showing an increasing contrast from top to bottom of the visual field. It may be concluded that interventions applied to urban areas and building pavements can improve visual adaptation in the transition zone.

The lack of urban-specific climate data is, today, one of the major limits for an accurate estimation of the building energy performance in the urban context. The urban climate is substantially modified by the “heat island” effect that determines an increase of the air temperature compared to the surrounding rural areas. By contrast, the weather data used to run the energy simulations normally refer to rural or suburban weather stations, causing relevant errors in the energy assessment, especially in hot climates.This study aims at evaluating the accuracy of the "Urban Weather Generator" (UWG), a model developed for generating urban weather files from rural weather data in order to improve the accuracy of the building energy simulations in the urban context.To this purpose, the model predictions have been compared to actual observations in different urban sites in Rome and Barcelona. The comparisons have been conducted for one year of observations for each site, focusing the analysis on summer and winter months. The model accuracy has been assessed through statistical analysis of the average error.Results show that the UWG model is able to capture the general trend of the urban temperature. The accuracy of the prediction increases for urban sites located in a rather homogeneous urban fabric in terms of building density and vegetation coverage. In these situations, the model allows a good prediction of the urban air temperatures with low computational requirement and it can be a useful tool to improve the accuracy of urban energy analysis. La falta de datos climáticos urbanos específicos es, hoy en día, uno de los principales límites para una estimación precisa del desempeño energético de los edificios en el contexto urbano. El clima urbano es sustancialmente modificado por el efecto "isla de calor" que determina un aumento de la temperatura del aire en comparación con las áreas rurales circundantes. Por el contrario, los datos meteorológicos usados para ejecutar las simulaciones de energía normalmente se refieren a estaciones meteorológicas rurales o suburbanas, causando errores relevantes en la evaluación energética, especialmente en climas cálidos. Este estudio tiene como objetivo evaluar la exactitud del "Generador de Tiempo Urbano" (UWG), un modelo desarrollado para generar archivos meteorológicos urbanos a partir de datos meteorológicos rurales con el fin de mejorar la precisión de las simulaciones energéticas de los edificios en el contexto urbano. Con este propósito, las predicciones del modelo se han comparado con observaciones reales en diferentes lugares urbanos de Roma y Barcelona. Las comparaciones se han realizado durante un año de observaciones para cada sitio, enfocando el análisis en los meses de verano e invierno. La precisión del modelo se ha evaluado mediante el análisis estadístico del error medio. Los resultados muestran que el modelo UWG es capaz de capturar la tendencia general de la temperatura urbana. La exactitud de la predicción aumenta para los sitios urbanos situados en un tejido urbano bastante homogéneo en términos de densidad de edificios y cobertura de vegetación. En estas situaciones, el modelo permite una buena predicción de las temperaturas del aire urbano con un bajo requerimiento computacional y puede ser una herramienta útil para mejorar la precisión del análisis de energía urbana. La manca de dades climàtiques urbans específics és, avui, un dels principals límits per a una estimació precisa de l'acompliment energètic dels edificis en el context urbà. El clima urbà és substancialment modificat per l'efecte "illa de calor" que determina un augment de la temperatura de l'aire en comparació amb les àrees rurals circumdants. Per contra, les dades meteorològiques que es fan servir per a executar les simulacions d'energia normalment es refereixen a estacions meteorològiques rurals o suburbanes, causant errors rellevants en l'avaluació energètica, especialment en climes càlids. Aquest estudi té com a objectiu avaluar l'exactitud del "Generador de Temps Urbà" (UWG), un model desenvolupat per generar arxius meteorològics urbans a partir de dades meteorològiques rurals per tal de millorar la precisió de les simulacions energètiques dels edificis en el context urbà. Amb aquest propòsit, les prediccions del model s'han comparat amb observacions reals en diferents llocs urbans de Roma i Barcelona. Les comparacions s'han realitzat durant un any d'observacions per a cada lloc, enfocant l'anàlisi en els mesos d'estiu i hivern. La precisió del model s'ha avaluat mitjançant l'anàlisi estadística de l'error mitjà. Els resultats mostren que el model UWG és capaç de capturar la tendència general de la temperatura urbana. L'exactitud de la predicció augmenta per als llocs urbans situats en un teixit urbà bastant homogeni en termes de densitat d'edificis i cobertura de vegetació. En aquestes situacions, el model permet una bona predicció de les temperatures de l'aire urbà amb un baix requeriment computacional i pot ser una eina útil per millorar la precisió de l'anàlisi d'energia urbana.