Improving urban resilience and habitability by an effective regeneration of the streets: A comprehensive approach step-by-step validated in a real case

Building and Environment 256 (2024) 111471 Available online 6 April 2024 0360-1323/© 2024 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/). Improving urban resilience and habitability by an effective regeneration of the streets: A comprehensive approach step-by-step validated in a real case Paz Montero-Guti´ errez, Teresa Palomo Amores, MCarmen Guerrero Delgado * , Jos´ e Luis Molina F´ elix , Jos´ e S´ anchez Ramos, Professor, Servando ´ Alvarez Domínguez, Professor Grupo Termotecnia, Escuela Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos s/n, 41092, Seville, Spain ARTICLE INFO Keywords: Urban resilience Urban regeneration Climate adaption Urban thermal comfort index Urban heat island Anthropogenic heat ABSTRACT The world’s average temperature has increased by 1 ◦C, leading to more frequent and intense extreme weather events. Attention has turned to the Urban Heat Island (UHI), a warming phenomenon in cities resulting from human activities and the urban design. In this way, urban adaptation of streets and the development of new urban spaces focus on achieving thermal comfort. While the research community proposed surface energy balances (SEB), a limitation arises from SEB’s ability to identify UHI due to its exclusion of anthropogenic heat. This study highlights the need to address anthropogenic variables and the importance of continuous monitoring in urban areas undergoing adaptation. A calculation method called co-simulation is suggested to incorporate anthropogenic heat using ENVI-met software as the basis. Adaptation justification involves monitoring and assessing the COMFA comfort index in an avenue. The calculation process proposes improvements for a comfortable environment, evaluating the microclimate impact on urban adaptation. Implementation, ongoing monitoring, and a comprehensive sensitivity analysis of the COMFA comfort index ensure a 60% improvement in the thermal sensation from June to September. This approach promotes the adoption of innovative solutions for climate change, emphasizing energy efficiency and well-being in urban spaces. Abbreviations ASHRAE American Society of Heating, Refrigerating and Airconditioning Engineers Q-COMFA Thermal or Heat Load Comfort Index PMV Predicted Mean Vote PPD Predicted Percentage of Dissatisfied PET Physiological Equivalent Temperature UHI Urban Heat Island C Comfort - Assessment scale SW Slightly warm - Assessment scale W Warm – Assessment scale H Hot – Assessment scale VH Very Hot – Assessment scale SEB Surface Energy Balance Symbols Q Thermal or Heat Load Comfort Index [W/m 2 ] M Heat produced by the metabolism [W/m 2 ] W Heat consumption due to the metabolic activity [W/m 2 ] C REQ Convective heat flux exchanged by the person [W/m 2 ] R REQ Radiant heat flux exchanged by the person [W/m 2 ] E REQ Perspiration required by the body [W/m 2 ] T SQ-REQ Skin temperature required to reach comfort conditions outdoors [K] CLO Unit of measure for dress typology [−] * Corresponding author. E-mail addresses: [email protected] (P. Montero-Guti´ errez), [email protected] (T. Palomo Amores), [email protected] (M. Guerrero Delgado), [email protected] (J.L. Molina F´ elix), [email protected] (J. S´ anchez Ramos), [email protected] (S. ´ Alvarez Domínguez). Contents lists available at ScienceDirect Building and Environment journal homepage: www.elsevier.com/locate/buildenv https://doi.org/10.1016/j.buildenv.2024.111471 Received 22 January 2024; Received in revised form 25 March 2024; Accepted 28 March 2024 Building and Environment 256 (2024) 111471 2 1. Introduction 1.1. Context Climate change represents the greatest environmental threat facing planet Earth today. In line with the assessment of the World Meteorological Organization (WMO), the impacts of such change are unequivocally manifested in the global climate, with an increase in the world’s average temperature by 1.2 ◦C since pre-industrial times [1]. This increase has led to an increasing frequency, intensity, and duration of extreme weather events, such as storms, hurricanes, droughts, fires and heat waves, which have caused significant social and economic damage since 2015 [2,3]. Similarly, attention has intensified on the concept of the Urban Heat Island (UHI). The term UHI refers to the phenomenon of warming in urban areas because of human activities and the configuration of the city, exacerbated by the predominance of paved surfaces and the scarcity of vegetation areas [4]. It becomes more necessary to transform and address the design of urban spaces to accommodate both the population and to face the challenges posed by change and its critical climate phenomena [5]. In this context, urban adaptation of streets and the development of new urban spaces focus on the search for thermal comfort [6,7]. 1.2. Urban adaptation Thermal comfort indicators refer to the ability of people to enjoy a healthy and pleasant urban environment, which directly affects the quality of life both outdoors and inside buildings. In interior spaces the concept of thermal comfort is intrinsically linked to the concept of air temperature, this being the fundamental variable to consider. Meanwhile, outdoor spaces are increasingly characterized by the intensity and frequency of heat waves, which have generated significant vulnerabilities among the inhabitants. Comfort in outdoor spaces depends on several variables of which the air temperature is only one of them and not the most important. The number of variables and the intensity of their manipulation depend on the characteristics of the space to be treated, the effectiveness and cost of the possible techniques to be used, as well as the possibility of the integration of these techniques without distorting their aesthetic objective. Therefore, it turns out that the combination of these variables to achieve a certain level of comfort outdoors is numerous [8]. Consequently, the interconnection between thermal comfort and habitability continues to be of interest in the scientific community. It is vital to review the current literature in search of procedures related to urban planning, renovation acts, adaptation and naturalization of urban canyons that focus on the study of these variables. Table 1 provides a summary of the state of the art, highlighting the objectives, methodology and implementation used by researchers in this field. This analysis aims to highlight the actions undertaken by the authors, the way in which they carry out their research, as well as the results that manage to adapt urban space to the effects of climate change. The literature review focuses on the investigation of the UHI effect and the adaptation of urban spaces through the application of methodologies based on energy balances and software such as ENVI-met [13,14, 16,17]. The methodology proposed by Oke. T. stands out, in which it exposes a superficial energy balance (SEB) [9,21,22]. Although most studies address radiant and convective heat flows or latent and sensitive heat flows [10,11,15], a limitation is observed in SEB models to detect UHI by not considering anthropogenic heat, a determining factor in the magnitude and intensity of climate change [12,18]. The main microclimate calculation software and current SEB methodologies offer an ideal approach to thermal variables, so it is necessary to analyze anthropogenic variables. It is also noted that researchers propose naturalization and urban reforestation as the main interventions for adaptation to climate change [6,7]. Recovering life in the streets is possible by improving the radiant properties of the urban elements that compose them, being necessary to quantify their effect to reduce the UHI effect and create a robust resolution methodology. The validation of the methodology is essential for the correct replicability of the proposed models. Although the literature monitors urban climate variables [11–14,18], it is important to note that only a minority of the authors complement this monitoring with the study of specific cases [13,15,16]. It highlights the need to address anthropogenic variables and the importance of continuous monitoring in urban areas undergoing adaptation processes. The objective is to evaluate the strategies implemented through computer simulation, so that monitoring and subsequent urban adaptation allow validating such simulations. 1.3. Objectives and research The main objective of this study is to implement a calculation method that incorporates anthropogenic heat as a fundamental component to understand and quantify the intensity of the UHI effect. To address this issue, the research group develops a co-simulation process based on the energy balances present in the literature. This is based on an iterative process that allows for more accurate calculations, using the ENVI-met microclimate simulation tool as the basis. The monitoring and measurement of the main variables are essential to validate the methodology and the COMFA comfort index. This study encourages the adoption of innovative solutions for climate change adaptation by increasing green areas, introducing pergolas and reflective pavements, with a focus on energy efficiency and recovery of street life and wellbeing. A detailed research process is established to validate a theoretical body, considering the innovative nature of the work and the scarcity of previous experiences dealing with these objectives. The stages on which research is based are analysis, experimentation, simulation, and validation (Fig. 1). These stages focus on the characterization and modelling of a representative urban canyon in which the detailed co-simulation process can be implemented. H abs Absolute humidity [g/m 3 ] Q ant Total anthropogenic heat [W/m 2 ] Q h Anthropogenic heat produced by humans [W/m 2 ] Q b Anthropogenic heat produced by buildings [W/m 2 ] Q t Anthropogenic heat produced by traffic [W/m 2 ] E factor Heat emission factor [J/m] N lanes Number of lanes of the studied street [−] L moderate Street length with moderate traffic density [m] L high Street length with high traffic density [m] D moderate Moderate traffic density [vehicles/h] D high High traffic density [vehicles/h] A street Floor area occupied by the urban canyon [m 2 ] h i Convective transfer coefficient [W/m 2 K] u Wind speed in the layers adjacent to the surface [m/s] V Wind speed [m/s] ACHd Air changes per hour [−] ˙ m Mass flow [kg/s] ρ aire Air density [kg/m 3 ] C p,aire Air specific heat [KJ/kg K] T int Air temperature inside the urban canyon [K] T ext Air temperature outside the urban canyon [K] T sup,i Surface temperature of urban canyon element i [K] H/W Aspect correction that relates the height (H) and width (W) of the urban canyon [−] P. Montero-Guti´ errez et al. Building and Environment 256 (2024) 111471 3 Table 1 Bibliographic analysis. Titles and references Aim Methodology Urban planning or adaptation Comments Canyon geometry and the nocturnal urban heat island: Comparison of scale model and field observations (1981) [9] Measurement and simulation of night cooling rates in rural and urban environments. Favorable weather conditions. Cities with despicable anthropogenic heat. Real experiment to simulate an urban model – Anthropogenic heat is not considered. Relation of urban geometry to UHI intensity. An urban canyon energy budget model and its application to urban storage heat flux modelling (1998) [10] Numerical modelling by Objective Hysteresis (OHM) to characterize environmental parameters that influence urban canyons. Implementation of energy balance as a simulation model. – Balance based on radiant and convective exchange. They do not consider anthropogenic heat. There are no measurements of thermal parameters. There is no real validation of the proposed model. A new single-layer urban canopy model for use in mesoscale atmospheric models (2011) [11] Development and validation of urban canyon model to calculate atmospheric variables. Study of the orientation and aspect ratio of the urban canyon. CFD analysis to study its effects, direction, and wind speed. Radiative and convective energy balance between different surfaces and air. – Validation of the model through measurements in urban cities. They do not consider anthropogenic heat. Street rehabilitation and improvement not addressed A multi-method and multi-scale approach for estimating city-wide anthropogenic heat fluxes (2014) [12] Study and development of energy balance by studying anthropogenic heat in different temporal and spatial resolutions. Detailed study of anthropogenic heat through heat due to human metabolism, electrical consumption of buildings and traffic volume of a city. Proposed method to analyze and predict the UHI of cities. Study of anthropogenic heat and thermal variables in the summer months. Validation of the model using measured data. Comparing the effects of urban heat island mitigation strategies for Toronto, Canada (2015) [13] Evaluation of UHI mitigation techniques using numerical simulations in ENVI-met. Measurement of thermal parameters in different urban configurations. Analysis of the progress of climate parameters through simulations in ENVI-met. Analysis of the improvement of the PET comfort index. Definition of case studies. Validation of simulation results with measurements made. – They do not consider anthropogenic heat. There is no real validation of study cases with in-situ measurements. Validation only with model in software. Street canyon design and improvement potential for urban open spaces; the influence of canyon aspect ratio and orientation on microclimate and outdoor comfort (2017) [14] Simulation of microclimates in 18 different urban canyons for design and implementation in cities. Measurement of climate variables in urban canyons during summer and winter. Proposed case studies. Use ENVI-met software to get the results. Analysis of the improvement of the PET comfort index. Sensitivity analysis of different climatic variables considering different orientations and aspect ratios H/W. PET comfort index analysis using heat maps and comparison between case studies. Anthropogenic heat is not considered. There is no real validation of study cases with insitu measurements. THIS – Tool for Heat Island Simulation: A GIS extension model to calculate urban heat island intensity based on urban geometry (2018) [15] Check the influence of urban geometry on the intensity of the UHI effect. Use of the theoretical-numerical model of T.R.Oke [9] Creating a calculation subroutine to enter ratio H/W. Adjustment of the new model by measurements in cities. Study of different scenarios. – Anthropogenic heat is not considered. The rehabilitation of urban canyons is not proposed through the implemented model Impact of urban canyon geometries on outdoor thermal comfort in central business districts (2020) [16] Analysis of the aspect ratio of urban canyons to define the microclimate and thermal comfort of the streets. Definition of case studies according to orientation and H/W. Simulation of microclimate with ENVI-met. Analysis of the PET comfort index. Discussion on improvements and new street design based on orientation and aspect ratio H/W. Anthropogenic heat is not considered. No measurements of climate parameters are made. The results are not validated. Evaluating urban outdoor thermal comfort: a validation of ENVI-met simulation through field measurements (2022) [17] Approach of a methodology to evaluate external thermal comfort and environmental parameters by simulation model Use of ENVI-met software for case calculation. Analysis of the PET comfort index. Study validation by monitoring variables. – Anthropogenic heat is not considered. The rehabilitation of urban canyons is not proposed through the implemented model. Development of a micro-scale heat island (MHI) model to assess the thermal environment in urban street canyons (2023) [18] Use of the H/W ratio towards a 3D perspective to calculate the energy stored in the control volume of an urban canyon. Study area where climate variables are monitored. Model development using personal energy balance (COMFA), meteorological data and urban geometry The MHI model is implemented and validated by in-situ measurements in the city. Estimation power of 87% of the UHI effect. Anthropogenic heat as the main protagonist of the energy balance and proposed model. Validation of the model by real measurements. Adaptation of urban canyons is not planned to use this method. Assessment of greenery in urban canyons to enhance thermal comfort & air quality in an integrated seasonal model (2023) [19] Simulation and modelling to investigate vegetation patterns that reduce air pollution and improve Use of ENVI-met to analyze the effect of vegetation on an urban canyon – Monitoring of variables as input data to the software. It is not considered energy balance with anthropogenic heat. They do not propose rehabilitation of building (continued on next page) P. Montero-Guti´ errez et al. Building and Environment 256 (2024) 111471 4 1. Analysis of the urban canyon: The pavements, facades and trees present in the initial case of the urban canyon are characterized, as well as the climate in which it is located. The objective is to analyze the problems caused by these urban elements on the main variables such as air temperature, relative humidity (RH), wind speed, average radiant temperature (TMR) and incident solar radiation. 2. Justification of the intervention: Once the case is defined, the problem is justified by theoretical bases of comfort outdoors and experimental processes where the mentioned variables are monitored. The data acquisition procedure and the COMFA comfort index analysis are detailed in depth. 3. Microclimate simulation: It is proposed to improve and adapt the urban canyon to create a comfortable space for inhabitants. It also details the calculation process carried out with ENVI-met and the cosimulation of anthropogenic heat to evaluate the external conditions of inhabitants and the impact of urban adaptation. 4. Validation: The process of calculation and co-simulation are only approximations of reality whose validity must be contrasted with real measurements after the intervention in the urban canyon. Thanks to this validation, a comprehensive sensitivity analysis of the COMFA comfort index is proposed, obtaining relevant information on all the variables involved in the study. 2. Case studies 2.1. Case study description The present work takes as a reference study the Avenida de la Cruz Roja in the city of Seville. Seville is characterized by a warm and temperate atmosphere, classified with a Csa climate according to the classification of K¨ oppen-Geiger [23]. During the summer, the city suffers recurring heat waves, considered one of the hottest cities in Spain [24]. The average maximum temperature during the months of June and September is 36 ◦C, being the minimum of 20 ◦C. Meanwhile, winters are usually mild thanks to the presence of sunny days. The winter lasts between November and March with average daily maximum temperatures of 20 ◦C and minimum 6 ◦C [25]. Fig. 2 shows the extent of Cruz Roja Avenue. The avenue has a linear length of 500 m between two streets that cross it: Ronda de Capuchinos and Manuel Villalobos. It is divided into 4 different segments by transverse streets, retaining a practically constant width of 10 m along its extension. In the last meters of street, it takes a width of 15 m due to the presence of a bus stop. The construction characteristics of the urban elements define the initial state of the avenue. The predominant pavement is asphalt, which occupies approximately 3.50 m wide. A two-lane bicycle lane occupies 1.75 m, located on one side of the asphalt. Finally, two sidewalks are located at the ends, taking a width of approximately 2.20 m each. On its margins are residential and commercial buildings that reach maximum heights of 15 m. Constant transit of motor vehicles and buses powered by liquefied petroleum gas (LPG) contributes to increased anthropogenic heat generation and retention. In addition, the vegetation is sparse, and it is in a deteriorated and aged state, resulting in the limited presence of shaded areas during the central hours of the day. It is imperative to adapt the avenue to recover its potential, especially given its unfavorable construction conditions and the severe weather of the city in the summer months. Thanks to the repeated width and height of the avenue a representative pattern is created. Fig. 3 shows a three-dimensional representation of the urban canyon, modeled by a cubic geometry. The section of avenue belonging to the last 100 m adjacent to the intersection with Manuel Villalobos Street is defined. This section is 15 m wide due to the presence of a bus stop. It consists of different establishments intended for leisure and commerce, which causes the sidewalks to be used to incorporate seats and tables. The canyon consists of 450 m 2 (15 ×30 m) of unfavorable pavement. The width and height of the surrounding buildings take on dimensions of 15 m. 2.2. Justification for intervention The following sections set out the theoretical bases that have made it possible to identify the problem in the urban canyon. The theoretical basis for the COMFA comfort index is explained in Section 2.2.1. Section 2.2.2 explains the experimental monitoring process that supports the need to improve the comfort of inhabitants in the canyon. 2.2.1. Outdoor thermal comfort indicators Urban comfort indicators are known for their ability to guide and Table 1 (continued) Titles and references Aim Methodology Urban planning or adaptation Comments thermal comfort in urban canyons. elements of streets, but they do typology of vegetation Design recommendations for the rehabilitation of an urban canyon in a subtropical climate region using aerial thermography and simulation tools (2023) [20] Adaptation of an urban space through the implementation of a methodology based on the use of thermography. Study of an urban canyon by acquiring thermographic data, measuring climate data and surveys. Analysis of comfort indices PMV and PPD Case study of adaptation using ENVI-met software. The case study for the adaptation of urban canyons is considered. No mention of anthropogenic heat. Fig. 1. Summary of the methodology. P. Montero-Guti´ errez et al. Building and Environment 256 (2024) 111471 5 advise on thermal impact in outdoor spaces. This section summarizes the mathematical formulation and all the variables necessary to define comfort. Thermal comfort is defined as the individual’s response to the thermal conditions of the environment. Most studies focused on thermal comfort outdoors make use of a purely physiological model and described by a mathematical model, allowing to calculate the outside comfort conditions. As a result, the established wind chill for each indicator is defined by a standard scale. The most common comfort indicators studied by the scientific community are COMFA and PET. Both are distinguished by their effectiveness and direct applicability in warm climates. According to the literature, COMFA values below 100 W/m 2 are accepted for the definition of these microclimates. The PET indicator is standardised for both indoor and outdoor climates, with indoor use predominating. In the present work, the COMFA (Q) indicator is used, which was proposed by Fig. 2. Avenida de la Cruz Roja in the city of Seville. Fig. 3. Initial state of the urban canyon. P. Montero-Guti´ errez et al. Building and Environment 256 (2024) 111471 6 Brown et al. [26] and later reformulated as COMFA +by Angelotti et al. [27]. Authors such as Kenny et al. [28,29] and Vanos et al. [30] demonstrate their great utility and validity. The thermal load indicator Q [W/m 2 ] is defined as the heat flow to provide (in winter) or dissipate (in summer) the human body to be in thermal comfort. This indicator belongs to the group of direct indicators due to the calculation using a basic measurement of environmental conditions [31]. The analysis of the COMFA indicator marks the social impact of urban adaptation. This work aims to establish this impact through a comprehensive sensitivity analysis showing a change in the indicator. The theoretical bases established in the literature have allowed to consider the main study variables that influence the occupant. Also, the COMFA index helps predict the influence of conditioning strategies on the occupant in terms of comfort, so that adaptation techniques are chosen to ensure optimal behaviour. A thermal balance on the human body is necessary to study the physiological response and therefore quantify the indicator (Eq. (1)) [32]: Q= (M−W) − (C+R)REQ −EREQ (1) M is heat generated by metabolism [W/m 2 ]; W [W/m 2 ], mechanical work, is the heat consumption due to the metabolic activity performed; (C+R)REQ are the convective and radiant heat flows exchanged by the person for a skin temperature TSK−REQ necessary to reach outdoor comfort conditions; and EREQ refers to the perspiration required by the body in accordance with ISO 7933:2004 [33]. Both terms are in Eqs. (2) and (3): TSK−REQ =35.7−0.0274⋅(M−W)(2) EREQ =0.42⋅(M−W−58.15)(3) Therefore, the thermal charge is the difference between the production of internal heat and heat losses for a person who is hypothetically in comfort. Researchers have shown that, in addition to complying that the indicator is within a certain range to ensure thermal comfort [34], it is necessary that the skin temperature and the sweat rate fall between certain values [35]. The definition of temperature and sweating required under the above standard would comply with the restrictions expressed and would also be consistent with other standards applicable to outdoor thermal comfort, such as those of ASHRAE 55 [36] and ISO 7730 [37]. Thanks to all these considerations it is possible to clear the thermal load level Q of Eq. (1). Table 2 helps to determine the thermal sensation of the occupant by means of an assessment scale [38]. Because the case study focuses on the warmer summer months (June to September), the scale of assessment in Table 2 is broken down to provide more detailed information. Table 3 reports this breakdown, focusing on the range of the comfort index from −50 (Comfort) to more than 150 W/m 2 (Very hot). The above consideration “Preferably colder” (Table 2) is divided into three: “Slightly warm”, “Warm” and “Hot”. The Thermal Load indicator is equally divided for each of the categories in Table 3 [38]. 2.2.2. Experimental climate assessment The city of Seville is characterized by recording every year maximum temperatures of 40 ◦C between the months of June and September. This is why these months are considered critical for the population. It is necessary to study the progression of air temperature, humidity, wind speed and radiation for different type days. The equipment used and its characteristics are detailed in Table 4. Fixed sensors with internal memory and 5-min sampling periods are used to measure temperature and humidity at different points along the avenue. Specifically, 4 sensors with these characteristics are used, each one located in the trees adjacent to each of the intersections of the avenue. These sensors are protected to block direct solar radiation and are in the treetops as detailed in the previous work carried out by the authors [24]. In addition, there is a Table 2 Rating scale for Thermal Load Indicator (Q). Heat load Q (W/ m 2 ) >150 50–150 −50–50 50–−150 < −150 Consideration Very hot Preferably cooler Comfort Preferably Warmer Very cold Table 3 Redefinition of the rating scale for the thermal load indicator (Q). Heat load Q (W/ m 2 ) >150 120–150 85–120 50–85 −50–50 Consideration Very hot Hot Warm Slightly warm Comfort Table 4 Monitoring equipment used for the acquisition of climate variables. Sensor - situation Measurement General characteristics OMEGA OM- 92 [39]- Treetop Fixed sensor of temperature and humidity powered by batteries. Variable temperature and relative humidity register selectable by software. The range for the temperature sensor is 5 to 60 ◦C and consists of an accuracy of ±0.3 ◦C. The range for humidity sensor is 20–80% with precision of ±3%. Weather station Cruz Roja Avenue Temperature and humidity: PT-100 sensor for temperature and capacitive sensor for humidity with built-in transmitter with 4–20 mA output. They consist of a sunscreen for solar radiation. The range for the temperature sensor is −10 to 70 ◦C, up to 100 ◦C in short time, and accuracy of +0.1 ◦C. The relative humidity sensor has a range of 5–98% with an accuracy of 2% to 20 ◦C in the range of 5–80% and 3% in the range of 80–95% Wind speed: Combined speed and wind direction sensor, with 4–20 mA transmitters with delay system. The wind speed sensor has a range of 0–35 m/s with precision of ±1%. The wind direction sensor consists of a range of 0 to 360◦ with ±2%. Radiation: Horizontal surface sensor for global radiation measurement using 12 receiving plates. Spectral response between 0.3 and 3 μ , with sensitivity of 15 mV per 1000 W/m 2 Fig. 4. Climate variables monitored in the months of June, July, August and September 2022. P. Montero-Guti´ errez et al. Building and Environment 256 (2024) 111471 7 fixed climate station to monitor wind speed and radiation, and in turn, temperature, and humidity. This station is located on the deck of one of the houses on the avenue. Fig. 4 shows the monitoring of the different climate variables during the hottest months of 2022 in the city of Seville: June, July, August, and September. It is observed that 20% of the days monitored present temperatures above 35 ◦C. The daily oscillation of temperatures is important, reaching an average value of 18 ◦C, reaching 23 ◦C on the hottest days. From the point of view of humidity, the climate of Seville is intermediate, reaching values of 25% for those days in which maximum temperatures are suffered. The wind direction is generally located in the southwest reaching mean gusts of 1.2 m/s. Finally, it is worth noting the radiation, which reaches very high values of 750 W/m 2 , close to the theoretical maxima according to the latitude of the place. Also, to finish contrasting the problem, surveys are made to passersby with the aim of knowing the thermal sensation in the studied area. Surveys are conducted in the study area throughout the monitoring period. The KoBoToolbox web tool [40] is used to generate the individual questions and answers of passers-by thanks to a mobile device. Table 5 details the process performed by the interviewer, which is divided into two clearly differentiated parts providing that the execution time is as short as possible. The interviewee only must answer three simple questions about their thermal perception according to the comfort index and how cold or warm the space is. These questions are related to the metabolic activity performed in the last hour, how the interviewee is usually defined in terms of thermal sensation (cold, normal, hot) and how the space finds in terms of thermal comfort (comfort, slightly warm, warm, hot and very hot). Moreover, the interviewer is responsible for entering data on the approximate age, sex, dress, metabolic activity in the interview moment, and mood of the interviewee. It is essential to record the location of the person using latitude, longitude, and altitude. To do this, use the application Geo Tracker (Android) and Maps 3D (iOS) to record geospatial coordinates. 1432 surveys were conducted in summer 2021 while in summer 2022 they amounted to 2063. Fig. 5 shows a summary of both percent of respondents, ages and clothing for summer 2021 and 2022. The interviews were conducted between June and September, the hottest months of the year. In the summer of 2021, 48% of respondents were women and 52% men. 12% were children and adolescents between 10 and 18 years, 65% were adults between 18 and 40 years, and 23% were people between 40 and 80 years. In the summer of 2022, a value similar to the percentages of 2021 is maintained considering gender. 18% were children and adolescents between 10 and 18 years old. 63% were adults between the ages of 18 and 40, and 19% were people between the ages of 40 and 80. 3. Urban canyon improvement and ENVI-met model 3.1. Urban canyon adaptation proposal The fundamental purpose of this paper is focused on the real adaptation of the proposed case study. A new distribution of the urban canyon materializes, including new urban elements thanks to the comprehensive study of the COMFA comfort index. Innovative technologies are incorporated that promote the use of materials that allow to reduce heat absorption and, therefore, increase the reflectivity of solar radiation. In addition, the importance of vegetation as a crucial component is recognized. The first action on the avenue focuses on restricting the anthropogenic generation due to motor vehicles, thus creating a pedestrian street and traffic-free street. The strategy consists in replacing the asphalt pavements of the road and the bicycle lane, which due to their characteristics have a high thermal absorption capacity. The concrete pavement has also been demolished to create a street with a level pavement. A space for bicycles and pedestrians is guaranteed with seats where people can perform leisure activities, enhancing the visual coherence of the adapted space. Meanwhile, trees damaged are removed with the aim of planting new species. The adaptation of the Cruz Roja Avenue is not limited to mere urban aesthetics but pursues a comprehensive approach in which advanced urban technologies predominate. Sustainable Urban Drainage Systems (SUDS) are installed to ensure a reduction in the average surface radiant temperature. Light colors permeable pavements are used to reflect the radiation. All implemented SUDSs make use of infiltration and catchment wells to subsequently reuse collected rainwater. This water strategy not only contributes to the efficient use of water resources, but also minimizes the risk of flooding and erosion on the avenue, increasing the useful life of materials. Fig. 6 shows the inclusion of a greater number of trees with respect to the initial state. Table 6 shows a summary of the species considered in the adaptation. In total 60 new trees are planted, and vegetation seats are provided for pedestrians to use the street. Trees are planted in which adulthood is guaranteed a sufficient crown and foliage to provide shade. This not only adds an attractive aspect to the avenue, but contributes to improving air quality, reducing ambient temperature, and reducing surface temperatures thanks to shade. Similarly, for existing and new vegetation, artificial rafts are used to capture, retain, and filter rainwater naturally. 3.2. Model and simulation in ENVI-met software ENVI-met is an integral system with the ability to model the urban climate through the interaction of landscape elements [41]. Through its results, it is possible to analyze the parameters of surface temperature and incident solar radiation. Later sections detail the design and simulation process of the study scenarios. Likewise, the external climate variables, the hourly renewals considered, the effect of convection with urban elements and the analysis of anthropogenic heat by co-simulation are specified. 3.2.1. Geometry and climate The geometry of the avenue is defined by the ENVI-met Spaces tool. In order to perform a detailed analysis of the space, a grid of equal cells with dimensions of 1 ×1 ×1 m is created, creating a three-dimensional mesh. These dimensions will increase the calculation time, however, it can be assumed because the size of the model will not be high and therefore allow a further analysis of the results in more detail. The correct definition of the vertical mesh is essential for the results to be consistent with reality. Therefore, the height of the models should be at least twice the maximum height in the space. All cells of the vertical mesh have the same dimensions, it is not necessary to make a greater discretization of the mesh near the ground (telescopic function). The Table 5 Survey campaign conducted on Avenida de la Cruz Roja. Questions to be answered by the interviewee Information about the interviewee provided by the interviewer Question 1: Have you done any activities in the last hour? Answer 1: Gender. Female/Male. Answer 2: Age. 10–18 years/18–40 years/40–80 years. Answer 3: Clothing. Spring clothing: light pants, long-sleeved shirt, shoes/Summer clothing: shorts or skirt, short-sleeved shirt, dress, sandals/shoes/Answer 4: Metabolic activity in that moment. Rest/ Low: Soft walking/Medium: Fast walking/High: Running. Answer 1: None/Somewhat (moderate – walking, housework)/A lot (high intensity – running, sports). Question 2: How do you usually define yourself in terms of thermal sensation? Answer 2: Cold/Normal/Hot. Question 3: How do you find the space in terms of thermal comfort? Answer 3: Comfort/Slightly warm/ Warm/Hot/Very Hot. P. Montero-Guti´ errez et al. Building and Environment 256 (2024) 111471 8 dimension of the modeled mesh is 15 ×30 ×15 m. (Fig. 7). The location is defined by the coordinates referring to the city of Seville: latitude 37.24 deg (+N,-S) and longitude −5.58 deg (-W,+E). The reference time zone is GMT+2 because standard summer days are tested. Selecting urban elements within the tool is essential to ensure accurate and realistic results. The most important urban elements in the adaptation of the avenue are pavements, building facades and vegetation. All selected elements belong to the ENVI-met database. Specifically, Albero is used for vegetation, in which the different tree species are defined, establishing the albedo and transmissivity data for each species. Also, Table 7 specifies the technical properties of the chosen elements. Climate data are essential for a correct definition of cases in the ENVI-met software. They are necessary to study the standard days for each reference month. Specifically, four standard days are defined; one for each hot month of the year 2022: June, July, August, and September. These meteorological data come from the continuous monitoring and detailed in section 2.2.1 whose summary is in Table 8. 3.2.2. Co-simulation and anthropogenic heat Surface temperature and radiation are the main results obtained through the simulation process with ENVI-met. This software allows to analyze the temporal evolution of incoming and incident solar radiation on the different surfaces defined in the canyons. It plays a fundamental role in the simulation process due to its effect on surface and indoor air temperatures. Despite this, ENVI-met is limited in establishing anthropogenic heat. Temperatures reach higher values because they are influenced by the anthropogenic heat of people, buildings, and traffic. This study proposes a co-simulation process (see Fig. 8) that allows to consider anthropogenic heat by performing an iterative process. Step 1 and 2 consists of creating the geometric model and defining the climate using the ENVI-met software, respectively. In step 3, the calculation procedure is performed which will give the output of the results of step 4. The results obtained are the radiation and the surface temperature for each defined urban element. Thanks to this, step 5 and 6 defines the co-simulation process, in which it performs an energy balance in the air of the urban canyon to determine the temperature of the interior air (Eq. (4)). These output data serve again as input data to the ENVI-met software to establish the different iterative processes. A total of 3 complete iterations are performed to validate the results obtained by ENVI-met. The energy balance considers the hourly calculation of anthropogenic heat, forced convection and hourly renewals in the canyon. ˙ m•Cp,air • (Tint −Text) = Qant +∑ i hi•Ai•(Tsup,i−Tint)(4) where Qant (W/m2), is the anthropogenic heat; Cp,air (kJ /kg K), is the specific heat of the air; Tint (K), is the temperature of the interior of the canyon; Text (K), is the temperature outside the avenue; Tsup,i(K), is the surface temperature of each of the elements defined in the urban canyon; Ai(m2), is the area of each of the surfaces of the elements that form the urban canyon. The mass flow ˙ m(kg /s)is obtained thanks to the air renewals produced in the urban canyon (Eq. (5)). The flow of air from outside enters the avenue at a certain speed. The geometry and height of the defined buildings are decisive in the time of exit of the renovation air. The mass flow m (kg/s) is obtained thanks to the air renewals produced in the urban canyon (Eq. (5)). Equivalent hourly renewals (ACHd) are defined as the number of times per hour that the total air volume in a space is completely renewed, being the variable used for the mass flow calculation. The canyon is surrounded by buildings whose heights (H) are equal to the width (W) of the street, so the ratio of both parameters (H/ W) is equal to the unit. It is shown that these geometries are influenced by a single vortex of air mass. Also, for an air inlet velocity equal to 1 m/ Fig. 5. Percent of interviewees for summer 2021 and 2022, classified in gender, age and type of clothing. Fig. 6. Adapted urban canyon. Table 6 Tree species plante don the Avenida de la Cruz Roja. Scientific name of the tree Height (m) Diameter (m) Sophora pyramidalis 15 6 Sophora jap´ onica 15 6 Brachychiton acerifolius 15 7 Paulownia 15 8 P. Montero-Guti´ errez et al. Building and Environment 256 (2024) 111471 9 s and for a height-to-width ratio equal to 1, the ACHd takes a value of 0,0141 [42]. ˙m Astreet •V• ρ aire =ACHd(5) where Astreet (m2), is the surface area of the urban canyon; V(m/s)the wind speed; ρ aire, is the air density equal to 1225 kg/m 3 . The wind speed obtained must be analyzed to obtain the coefficient of convective film between the surfaces of the facades and the air. The wind acts as an external force that causes air movement in the urban canyon. Air collapses with different surfaces and buildings, creating high and low-pressure areas. Eq. (6) allows the calculation of the convective transfer coefficient hi(W/m2K)[43]. This coefficient depends on the value of the wind speed near the outer surface considered, u(m/s), differentiating between the surfaces that are at leeward or windward (Eqs. (6)–(9)). The west façade of the present work is considered downwind because the prevailing wind in Seville comes from the southwest. The east facade and pavement are considered windward. hi=3,5+5,6u(6) Windward :V>2m/s u =0,25 •V(7) Windward :V<2m/s u =0,5(8) Leeward u =0,3+0,05 •V(9) Anthropogenic heat is the critical variable for defining cosimulation. Eq. (10) summarizes that this fact is influenced by the metabolic activity of humans (Qh), the heat produced by the heat installations of buildings (Qb)and the heat generated by traffic (Qt). This work focuses on specifically studying Qt. Qant =Qh+Qb+Qt(10) Traffic is quantified for the city of Seville, allowing its influence on the streets to be characterized [44]. Determining the contribution of heat produced by traffic requires information on traffic density, types of vehicles passing through the avenue, types of fuels, consumption, and characteristics of the road (Eq. (11)). Qt=Efactor •Nlanes •(Lmoderate •Dmoderate +Lhigh •Dhigh) Astreet (11) where Efactor (J/m), is the emission factor which depends on the type of vehicle and its consumption; Nlanes, is the number of lanes on the street; Lmoderate,Lhigh, is the total length of the street with moderate and high traffic density; Dmoderate,Dhigh, is the number of vehicles per hour for each type of traffic. As shown in Fig. 9, 85% of the anthropogenic heat is caused by combustion vehicles circulating along the avenue in the previous state to adaptation. The remaining 15% is due to the regular passage of LPG Fig. 7. Modelling urban canyons in ENVI-met software. Table 7 Construction characteristics and properties of urban elements in the previous and later state. Urban element Previous state Later state Pavements There are three types of pavement: Tread pavement: Dark black asphalt. Reflectivity equal to 0.1. Steel: Medium grey concrete. Reflectivity equal to 0.5. Bike path: Medium green concrete. Reflectivity equal to 0.5. The asphalt pavement is eliminated. The full width of the avenue is formed by concrete of reddish, orange and light green colors. Reflectivity equal to 0.9. Facades Two residential facades on each side of the avenue with a first floor for leisure. The total height of the facades is 15 m. Vegetation Three Sophora-Japonica trees are defined with a height of 10 m. All are located on one of the sidewalks, the other being deserted by vegetation. Albedo: 0.60. Transmissivity: 0.30. A total of 5 additional new Sophora-Japonica trees are defined according to project planning. They have a height of 10 m. Albedo: 0.60. Transmissivity: 0.30. Table 8 Initial weather conditions introduced in ENVI-met software. June July August September Measured wind speed at 15 m (m/s) 1.5 1.7 1.7 1.2 Direction of wind (deg) 225 225 225 225 Minimum air temperature (◦C) 18 20 19 16 Maximum air temperature (◦C) 37 37 39 33 Minimum relative humidity (%) 25 21 21 26 Maximum relative humidity (%) 90 81 78 85 P. Montero-Guti´ errez et al. Building and Environment 256 (2024) 111471 16 Fig. 17. Sensitivity study for study day in July and for two metabolic activities: rest and light pedestrian activity. P. Montero-Guti´ errez et al. Building and Environment 256 (2024) 111471 17 Fig. 18. Sensitivity study for study day in August and for two metabolic activities: rest and light pedestrian activity. P. Montero-Guti´ errez et al. Building and Environment 256 (2024) 111471 18 Fig. 19. Sensitivity study for study day in September and for two metabolic activities: rest and light pedestrian activity. P. Montero-Guti´ errez et al. 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