Thermal-Perception-Driven Adaptive Design for Wellbeing in Outdoor Public Spaces: Case Studies in Naples

(1)

(2)

Editorial Advisory Board

PasqualeArgenziano,University of Campania, Italy

MagdaBaborska,Wroclaw University of Science and Technology, Poland ChiaraBartalucci,University of Florence, Italy

SeckinBasturk,Aecom, UK

NunziaBorrelli,Università degli Studi di Milano-Bicocca, Italy BiagioCillo,University of Campania, Italy

LauraEstevezMauriz,Chalmers University, Sweden KarloFilipan,Ghent University, Belgium

GioiaFusaro,University of Sheffield, UK FarnazGanji,University of Sheffield, UK

EfstathiosMargaritis,University of Sheffield, UK

MariaJoseMartinezSanchez,Birmingham City University, UK BobbyNisha,University of Sheffield, UK

GiuseppinaEmmaPuglisi,Politecnico di Torino, Italy VirginiaPuyanaRomero,University of Campania, Italy AntonellaRadicchi,Technische Universität Berlin, Germany JimSloan,Birmingham City University, UK

CristianSuau,Studiopop, UK

CarolinaVasilikou,University of Reading, UK

XiWang,Huazhong University of Science and Technology, China NicolòZuccheriniMartello,University of Ferrara, Italy

(3)

Chapter 9

DOI: 10.4018/978-1-5225-3637-6.ch009

ABSTRACT

The spread of digital technologies, aiming at improving the effectiveness of the technological and en-vironmental project proposals, has transformed the modus operandi for architects and designers who approach environmental impact assessment, especially about public space designs. Research activities aim at collecting guidelines for the sustainable regeneration of public spaces, focusing on the effective-ness of the performance of individual actions proposed by gradually checking and fixing the convenient benchmark design required by norms and sometimes by technology and building best-practices widely consolidated, even on a scientific basis. Early design optimization process relies on the combined use of appropriate IT tools for environmental control and on the interoperability of these systems with the traditional modeling tools for outdoor and indoor spaces. According to data-design-oriented logic, the core of the research methodology is applied to three case studies concerning public “complex” open spaces within the Neapolitan urban context (Italy).

Thermal-Perception-Driven

Adaptive Design for Wellbeing

in Outdoor Public Spaces:

Case Studies in Naples

Luciano Ambrosini

University of Naples Federico II, Italy

Eduardo Bassolino

University of Naples Federico II, Italy

Francesco Scarpati

(8)

Thermal-Perception-Driven Adaptive Design for Wellbeing in Outdoor Public Spaces

INTRODUCTION

Our cities take a remarkable role inside the global adaptation and mitigation policies to face the Climate Change effects. Considering what IPCC have been declaring since 2007, the same cities will become overcrowded in the next years till 2030, and will be always more conditioned by extreme thermal states and lower possibilities of water supplies (IPCC 2007) - that is more worrying. The poorest bracket of the population, especially old people and children, will have to face a lack of liveableness in outdoor public spaces and an increase of diseases and death rate as a natural consequence of the high rates of the (middle temporal periods) due to heat waves. Another important factor in the alterations of the best thermohygrometric comfort is due to the local microclimatic altered conditions caused by the urban heat island effect1_{(UHI). All these elements constitute a direct consequence of the synergic interaction}

between the urban morphology (see Ratti, 2003) and the specific material features which constitute the built environment surfaces (see Givoni, 1998).

Acting directly and systematically on the conditions described above becomes a priority from which the designer of the “city of the future” cannot shirk. Facing the problem systematically means acting on the building, trying to pursue operational strategies to mitigate the environmental aspects of the open space without neglecting the component of the architectural quality of the “design gesture”.

Having prior knowledge of environmental and architectural conditions represents a first step towards an intrinsic knowledge of the open space to be able to adapt and resist even the most aggressive climate events. This knowledge triggers virtuous actions on “suffering spaces” to contribute positively to their regeneration both outside and inside building wellbeing perception. The knowledge and the relation-ship between all the boundary conditions allow to structure the meta-design phase better and adopt consciously more “holistic” technical solutions. The possibilities offered by the world of any software for architecture are pushing forward the boundaries of traditional design thanks to advanced digital tools for the digitization of the processes. A co-utilization of these virtual platforms highlights the existence of some local critical situations according to a wider and selective vision in the verification phase and in that of the decisional support to the designer in complex urban contexts.

The importance attributed nowadays to the “information flow” is mainly due to the awareness of enriching our design culture with new concepts as “data mining”, “datafication” and “data storage”. They are the basis of the growing demand for new professions with computational skills and parametric/ algorithmic oriented thinking, indispensable to deal with complex contexts. The scenarios presented by this cultural approach will be able to produce an interpretation of open spaces as to ensure better ef-fectiveness of the proposed strategies, manifesting the current trend of more “data informed” promoting projects that will better support the phases of “decision making” at every level.

Pursuing this approach, to better define the methodology that led to significant theoretical design results, was undoubtedly the goal of the three following reports, focused on the well-being perception and the design complex management by advanced IT tools. It is worth highlighting how the “complex-ity” and the systemic approach are nowadays often juxtaposed to the issue of “interoperabil“complex-ity” among computer platforms. This last notation of scientific and practical interest is the base for any technical knowledge and its critical advance as a consecution of the relentless digital revolution.

These tools allow to develop environmental and microclimate analysis of the built environment (sunlight, ventilation, Sky View Factor - SVF, etc.), analysis about the perceived thermal comfort in the open space such as the Predicted Mean Vote - PMV (Fangers 1972, UNI-EN-ISO 7730: 1996), the

(9)

Physiologically Equivalent Temperature - PET (Mayer, Höppe 1987; Höppe 1999; Matzarakis et al.1999), the Mean Radiant Temperature - MRT (UNI-EN-ISO 7726: 1998), and the performance analysis of the current scenery on which the authors have carried out their investigation routines.

The use of software to run complex analysis inside the urban open space provides a detailed under-standing of the environmental phenomena that arise from natural components (sun, wind, humidity, vegetation, etc.) and anthropogenic ones (buildings, roads, etc.). Considering the simulation software available, ENVI-met 3.1 Beta 5 (now EM software) has been chosen in this case as the fulcrum for the analytical research of the urban thermal comfort in different contexts. This software simulates the urban microclimate considering the dynamic interactions among atmosphere, soil physics and the response of vegetation, allowing a critical analysis of the environmental system behaviour. Through a three-dimensional reconstruction of the urban space, the setting of the physic and chemical characteristics of the horizontal and vertical material surfaces, the vegetation, the climatic and morpho-physiological characteristics of a “generic user” (walking speed in m/s, thermal and clothing exchange - clothing CLO), it is possible to evaluate the environmental characteristics and performance of the urban space.

The choice of case studies concerned three selected areas characterized by morphological identities and different surface treatments because of the overlapping of several historical events. The coexistence of historical and contemporary contexts is clearly visible in the Eastern area of Naples (Ponticelli) and even in the hill district of Vomero (Borgo Antignano) whose functional organization, with its local market, is linked to daily and perceptive life of one of the historical districts in the heart of Naples (Duchesca).

Every case study has been a testing ground to define, verify and dynamically upgrade an analytic methodology to define the urban thermal comfort into different urban patterns of the city of Naples. The evolution of these processes has been developed through the achieved previous expertise and the pro-gresses made to define new configurations and ways of using data from different simulation software to reach the double and complex objective to define a virtual environment (by exchanging data platforms), to manage the complexity of the dynamic simulation of the indoor/outdoor thermal comfort related to climate change conditions (see Peng and Elwan, 2012).

THE FIRST CASE STUDY: PROGRESSIVE CLIMATE

ADAPTIVE DESIGN IN THE EAST AREA OF NAPLES

The use of specific IT tools and software for the investigation of the factors and the solutions that contribute to the urban microclimate variation, can provide the definition of strategic actions for the improvement of comfort conditions of the open spaces of our cities, mostly in anticipation of climate changes.

By the acquisition of useful data and information to evaluate climatic, environmental and morpho-logical conditions of the built environment, the use of IT tools for environmental simulations allows to appreciate the performances and the adaptive responses of urban spaces, both for actual and future climate scenarios. This approach allows to identify the elements that make more critical the use of open spaces during the summer season, and then, to determine the best strategy suited to the environmental conditions and to the analysed context, by introducing new features and technical solutions to ensure better performances in terms of environmental comfort.

The process of analysis and verification of the performance about the rising temperatures in a climate change condition can be conducted with the support of those IT tools that could give the opportunity

(10)

to perform simulations of future climate scenarios, as well as to give back outputs regarding offered performances in terms of perceived comfort. Between all the software able to provide environmental simulations, the choice to carry on an experimental research experience has fallen on ENVI-met 3.1 beta 5, that allows to generate three-dimensional microclimate simulation and provide data on environmental thermal comfort conditions.

This simulative approach has allowed to determine what are the most environmentally critical aspects within the purpose of the study, and then to be able to test, evaluate and validate the design solutions that would guarantee better levels of adaptation and mitigation of climate-changing factors for design projects, both in current and future climate conditions, considering the IPCC’s projections of thirty years from 2040 to 2069 (2050s)2_.

Objectives and Definition of Study Area: The Historical

Centre and the Eastern Area of Naples

The areas selected for the analysis and simulation of climate adaptive design strategies are situated within the boundaries of Eastern Naples (Figure 1), with a surface area of about 24.45 km2_{, which has}

inhomogeneous spatial and morphological characteristics: 1) the historic city, 2) the consolidated city, 3) the contemporary city, 4) the urban sprawl, 5) brownfields. Within the study area, we decided to focus the attention on three specific areas, Via Duomo in the historic city (TP8S), Piazza San Francesco di

Figure 1. Identification of the focused areas for the verification of the performance of summer environ-mental comfort with integrated adaptive design solutions for urban spaces

(11)

Paola in Nineteenth century city (T89P), and a residential complex in Via Fratelli Grimm (Ponticelli) in the contemporary city (TP9C). This choice has allowed us to identify different levels of response to extreme events and weaknesses in different parts of the study area through environmental and perfor-mance analysis by using IT tools.

Detection of Environmental Characteristics

The different morphological and spatial configurations between urban elements and their relationship, the presence of vegetation and the characteristics of the materials that define the urban space, play a key role on the variation of urban microclimate. The interaction between the buildings and surrounding open spaces is critical in performing direct and indirect surveys and measurement efforts on environ-mental conditions of the open urban space. In this way, it is possible to make a preliminary diagnosis and verifications of those aspects that appear to be more critical, and the way they affect the microclimatic conditions of the urban contexts.

For this purpose, it was decided to carry out a survey campaign on the environmental conditions of the study areas on the date of the 3rd_{of July 2015 (a day falling in a heatwave period}3_{), to obtain}

environmental data about the physical properties and thermal performance of the materials that line the horizontal and vertical surfaces of the open spaces of the city. This operation was carried out with a FLIR E40 BX thermal camera, which made it possible to detect reflected temperatures of the surface, a thermo-anemometer EXTECH AN200, for the detection of wind speed, and a hygrometer with IR thermometer, FLIR MR77, to obtain data on the air temperature, relative humidity and data on the emissivity of materials.

In this way, it was possible to perform a review of the materials most commonly used for the lining of horizontal surfaces present within the study area. Useful data were also collected about the physical and thermal properties of materials, such as the albedo, the emissivity, the roughness and the thermal conductivity (table 4, Appendix 1), to identify the techniques, and then the stratigraphy, of the pave-ments of the city of Naples. A database containing material properties, together with the data of the microclimatic factors, have been a useful tool to perform a kind of software calibration suitable for the site and the microclimatic specific analysis.

Microclimatic Analysis With ENVI-met

The collection of climate data and files, the direct environmental survey and the gathering of data of the built elements and the natural ones, in addition to the filing of the properties of materials and technology packages of pavers that define the study area, are useful information to conduct simulations in ENVI-met 3.1, which, at the end of the process, allows us to extract the required data to analyse and determine the perceived comfort by the users in the open spaces.

Before performing the simulations, and before generating the 3D model of the study areas, it was necessary to customize the software by modify the software’s libraries with the characteristic materials and technological packages of pavements of the city of Naples (Figure 2). Moreover, new types of plant elements were added: trees of 3, 5, 7 and 12 m height and a grass of 6 cm height.

The simulation areas have been three-dimensional modelled within the software, paying particular attention to report: the height of the buildings and the presence of portals and underpasses; the shape and size of the buildings; the orientation of the buildings; the materials of the open spaces; the size,

(12)

type and location of the vegetation of the open spaces; the shading elements (canopies, fixed and mobile screens, curtains, etc.); bodies of water (pools, fountains, water jets, etc.).

At the end of the modeling process, it was necessary to configure the software to generate the analy-sis by entering the data on: wind speed [m/s]; wind direction [degrees 0: N 90: E 180: S 270: W]; air temperature [K]; relative humidity at 2m [%]; specific humidity to 2500 m [g Water/kg air]4_{, average}

of U thermal transmittance of the external vertical partitions of the buildings within the area [W/m2_K];

U thermal transmittance of the external horizontal partitions average of the buildings within the area [W/m2_{K]; albedo factor of the walls, albedo factor of the roofs, roughness of the built environment}4_,

temperature inside buildings.

The software was set to simulate the behaviour of the entire daily cycle, starting at 6 am, until the desired time, in our case at 12 am. Before that, it was necessary to collect climate data of temperature, relative humidity and wind direction and speed of the previous 24 hours from the beginning of the simulation to perform an average:

• Wind speed = 2 m/s; • Wind direction = 247°;

• Air temperature = 300 K (26.85 °C); • Relative humidity at 2 m = 47.15%;

• Specific humidity at 2500 m = 2.8731 g/kg.

The inserted data were verified so that the software could return values closer to the real ones with an acceptable deviation, obtained as a result of the instrumental survey (air temperature, relative humid-ity, wind speed and direction, surface temperatures). In addition, some values were attributed to initial temperature and relative humidity at different levels of depth of the horizontal surfaces, assuming aver-age values of:

• 303 K (29.85 °C) for the temperature upper layer and 30% relative humidity for the surfaces from 0 to 20 cm;

• 298 K (24.85 °C) for the temperature middle layer and 40% relative humidity for the surfaces from 20 to 50 cm;

• 295 K (21.85 °C) for the temperature deep layer and 40% relative humidity for the surfaces below 50 cm.

Figure 2. Scheme of the customization of the materials within ENVI-met. Scheme developed by CEC4 board of Urban Green System project (Source: www.greenurbansystems.eu)

(13)

The configuration of the environmental and climatic factors was completed by entering data on the average of thermal transmittance of buildings and the average albedo of facades and roofs.

Finally, to determine the level of environmental comfort, expressed by the PMV5_{thermal comfort}

index, the subjective variables for human body, such as the activity (sitting, running, etc.) and the type of clothing related to the human body’s energy budget of a person exposed to that corresponding climate, were taken into account. In this case, it was assumed a generic person (adult man, 35 years old, 175 cm high, 75 kg), walking at a speed of 0.83 m/s, which had an activity of energy exchange of 116 W/m2

with the environment6_{and a corresponding clothing factor}7_{of 0.5.}

A similar procedure was used for the simulations to 2050s, modifying the only values of air tem-perature, relative humidity and specific humidity at 2500m. The data were extracted from projected climate files8_{for 2050s, referring to the average of the previous 24-hour values at 6 am in the morning}

of the 3rd_{of July:}

• Air temperature = 302.4 K (29.25 °C); • Relative humidity at 2m = 47.15%;

• Specific humidity at 2500m = 3.3272 g/kg.

At the end of the simulations in 2015 and 2050s, it was conducted a meta-design verification of environmental and comfort performances on the three study areas, assuming two application scenarios, light and hard, in which different levels of adaptive design strategies were planned: cool materials (table 5, Appendix 1), urban greening, shading systems, bodies of water, etc. For all simulations, data were extracted on minimum, maximum and average values relatively to PMV, Sky View Factor and air tem-perature (Ta). (Figure 3, see also Figure 12 and Figure 13, Appendix 1).

Results and Considerations on the Application Case

The meta-design phase and the verification of the adaptive capacity of the open spaces of eastern Naples have allowed to define the levels of microclimate and thermal comfort performance that can be achieved in different analysed city spots, also related to the climate prediction scenarios. From the comparison of the average values of air temperature and PMV values of the examined areas at actual and meta-design (light and hard) scenarios (Tables 1 and 2), it is clear that, thanks to the application of adaptive design actions, their capability and extent can contribute to the improvement of urban microclimate until reach-ing the comfort conditions acceptable durreach-ing the current and future summer period (2050s).

The developed experimental procedure, applied within the study area, contributed to obtain useful information and data to understand what are the characteristics of the open spaces that influence most the perception of comfort in the Neapolitan area and define which strategic actions for the adaptation to the reduction of high temperatures could be proposed within the analysed urban environment, in order to achieve adequate levels of perceived comfort during summer seasons and in case of heatwaves.

The application of a widespread strategy on the entire study area, which provides the combined adoption of design solutions that can ensure more microclimatic benefits to open spaces, can guarantee a diffused improvement, even where it is not possible to intervene. In fact, in the areas where can be achieved high levels of environmental comfort, there will be a positive influence both on the buildings and on the areas immediately nearby (see. Doick K., T. Hutchings, Air temperature regulation by urban trees and green infrastructure, Forestry Commission, Farnham, UK, 2013).

(14)

Figure 3. Area of the historical centre of Naples: results of microclimatic analysis and comparison of values of SVF, PMV and air temperatures

(15)

The eastern area and the historic centre of Naples constitute a representative urban tissue of the morphology and microclimatic conditions of the Neapolitan territory. The design proposals and the verifications carried out allow to define strategic actions of adaptation to climate change, calibrated on the specific needs of different urban plots. These actions may be applied to the open spaces with comparable morphological characteristics and outdoor comfort performances, to ensure a widespread improvement and maximize the reduction of temperatures in the city. The aim is to create places with high resilience to climate change, ensuring the triggering of a self-regulating process at the local scale, by improving quality of life, strengthening the social economy to the entire municipal area.

Table 1. Comparison between the average of air temperature values as result of ENVI-met simulations for meta-design alternatives: absolute and percentage reduction

Meta-Design Alternative _{Mean 2015}T Air _{T Air 2015}Reduction Percentage _Reduction T Air Mean _2050s _{T Air 2050s}Reduction Percentage _Reduction

TP8S – Hard scenario 27,27 °C -4,02 °C -12,85% 28,57 °C - 4,21 °C -12,84% TP8S – Light scenario 29,16 °C -2,13 °C -6,81% 30,65 °C - 2,13 °C -6,50% TP8S – Actual scenario 31,29 °C - - 32,78 °C - -T89P – Hard scenario 27,32 °C -6,63 °C -19,53% 28,60 °C - 6,68 °C -18,93% T89P – Light scenario 29,28 °C -4,67 °C -13,76% 30,75 °C - 4,53 °C -12,84% T89P – Actual scenario 33,95 °C - - 35,28 °C - -TP9C – Hard scenario 26,89 °C -4,96 °C -15,57% 28,17 °C - 5,19 °C -15,56% TP9C – Light scenario 29,11 °C -2,74 °C -8,60% 30,60 °C - 2,76 °C -8,27% TP9C – Actual scenario 31,85 °C - - 33,36 °C -

-Table 2. Comparison between the average of PMV values as result of ENVI-met simulations for meta-design alternatives: absolute and percentage reduction

Meta-Design Alternative Mean PMV 2015

Reduction

PMV 2015 Percentage Reduction PMV Mean 2050s PMV 2050sReduction Percentage Reduction

TP8S – Hard scenario 2,78 - 2,21 -44,29% 3,16 -2,32 -42,34% TP8S – Light scenario 3,70 - 1,29 -25,85% 4,29 -1,19 -21,72% TP8S – Actual scenario 4,99 - - 5,48 - -T89P – Hard scenario 3,22 - 3,11 -49,13% 3,61 -3,27 -47,53% T89P – Light scenario 4,17 - 2,16 -34,12% 4,63 -2,25 -32,70% T89P – Actual scenario 6,33 - - 6,88 - -TP9C – Hard scenario 2,69 - 2,58 -48,96% 3,08 -2,71 -46,80% TP9C – Light scenario 3,83 - 1,44 -27,32% 4,29 -1,5 -25,91% TP9C – Actual scenario 5,27 - - 5,79 -

(16)

-Thermal-Perception-Driven Adaptive Design for Wellbeing in Outdoor Public Spaces

THE SECOND CASE STUDY: URBAN REGENERATION

PROJECT OF BORGO ANTIGNANO, NAPLES

The identification and recognition of the “genius loci” was an operation strongly characterized by a careful study of the Neapolitan rural hillside district in historical, morphological and environmental terms, thanks to an experienced multidisciplinary approach able to transform these elements in project invariants. The geometric and technological peculiarities of the built environment constitute the meta-design elements from which the urban space meta-design and its impact on the perception of the end-user’s physiological well-being arise.

An important role has been attributed to the digital simulation of materials and surface technical solu-tions considering physical aspects such as: albedo, roughness, emissivity, permeability, etc. (Table 3).

Other important boundary conditions, represented by the environmental characteristics of the place, are: diffuse and direct solar radiation, shading and natural ventilation. The interaction among these fac-tors causes a response of the entire built environment which would be difficult to assess and manage without an iterative digital approach in the definition of adoptable choices. A support to the evaluation of the design response, according to a “before” and “after” planned intervention, has been revealed as one of the research objectives to be pursued.

The specific characteristics and the technological and environmental peculiarities of the urban space have been treated and coded as physical variables, or rather “data / information”, describing the domain of the possible decision-making. In this context, the designer refines his actions according to the possible consequences of the climate change effects. The main difficulty of undertaking a study about the urban open space wellbeing perception, despite the discretization of occurring variants, is connected to the fragmented stream of each simulation results obtained using multiple advanced IT tools simultaneously. The approach to the case study has been connected to a data design topic, as outlined by the following synoptic framework (Figure 4, - Figure 1 in Ambrosini, L. & Bassolino E., 2016):

The meta-design planning phase of the proposal strategies took place within one virtual development environment, disengaging from the fragmentation of information and, at the same time, optimizing its

Table 3. Pavements materials used for the simulations

ID Material Albedo Emissivity SRI Roughness

pl Lavic stone 0.32 0.90 34 0.010

po Porfido 0.30 0.63 19 0.015

pr Reassembled lavic stone 0.50 0.80 55 0.030

s Asphalt 0.15 0.93 14 0.016

p Pavement concrete 0.30 0.63 19 0.015

2s Asphalt Cool (light grey) 0.60 0.90 72 0.010

nc Natural charcoal 0.27 0.91 29 0.030

ab Asphalt block 0.41 0.86 45 0.012

h1 Reassembled cement 0.64 0.91 78 0.010

(17)

management according to an algorithmic and parametric oriented approach. The flexible structure, offered by 3D and CAD modeling software Rhinoceros (RH) and its plug-in Grasshopper (GH)9_{, has}

provided valuable support to design the generative codes, scripts and computer visual programming languages, merging them with the creative and artistic gesture of the architectural sketch. Virtual-model and information-model can coexist and interact in the same workspace allowing the designer to explore new relationships and correlations between “tangible and intangible” elements of project.

Design Workflow

Following the problems described above, the analysis proceeded with the study of the current scenery of the Borgo Antignano, organized into five connected steps (the same method was adopted to the pro-posal strategies):

Step 1: 2D/3D Modeling of the study area

Step 2: Configuration/simulation of environmental analysis

Step 3: Numerical modeling, microclimate simulation and configuration Step 4: Importing, exchanging and analysing data in RH + GH

Step 5: Evaluation and comparison of the results

Modeling of the Study Area

The three-dimensional model was based on data maps provided by the Town Council. The study focused on four urban spaces: Piazza degli Artisti, Piazzetta Borgo Antignano, via Annella di Massimo, Via Gioacchino Rossini.

The topographic pattern was modelled by RH plug-in, Lands-Design Asuni CAD S.A, extrapolating information from the Google Earth database.

(18)

Environmental Analysis

The three-dimensional model is useful for running the virtual simulations relating to the incident solar radiation, shading and lighting setting up the local climatic data by EPW file (EnergyPlus Weather data). The dynamic interaction among results obtained and subsequent modification of the three-dimensional model was guaranteed by the algorithmic definitions of the GH plug-in, Ladybug (LB)10_{. The algorithm}

developed in GH, Environmental Analysis.gh, was implemented to better adapt itself to the investigative purposes. It made possible to isolate the urban areas subjected to greater thermal stress due to direct and diffuse solar radiations. These areas could be identified entering (by numeric slider) a flag-value of solar radiation (KWh/m2_{) as input. The main advantage is the possibility of displaying on the model}

the difference between the flag value and the radiation peak ones and the ability of concentrating the design intentio on the most exposed areas to diversify the technical solutions.

The natural ventilation study was conducted by the calculation module Winair (developed by the Cardiff School of Architecture in 2007) add-ons of Autodesk® Ecotect® Analysis 2011, relating dynamically the CFD analysis results from Ecotect to the built environment modelled in RH (the definition includes the components of the GH plug-in Geco). The data exchange operation has simplified the identification of the most exposed urban areas as potentially microclimatic discomfort areas.

Microclimate Simulation

The simulation of the microclimatic conditions of the open spaces has been carried out with the micro-climatic holistic simulation software ENVI-met 3. To describe the characteristics of local materials, an ad hoc materials package, able to provide plausible answers in terms of thermal comfort and discomfort for the study area before and after the proposal strategies, has been encoded. The operating modes have been divided into:

Step 1: Numerical modeling of study area (buildings, paving, vegetation) Step 2: Setting of the configuration file (to run simulation)

Step 3: Running simulations

Step 4: Creating data tables containing the results of the simulations Step 5: Viewing and/or exporting the results

Exchanging Data and Results Analysis

The visualization and exploration of the results imported from Excel, as exchange format, has been improved by programming some appropriated GH components within the ENVItoGH.gh definition (SortingCells, ColorsAssigment). The author has compared some of the most significant parameters - like the Mean Radiant Temperature, Relative Humidity, Potential Temperature and Wind Speed – inside the computation cells, defined by ENVI-met software (Figure 5).

The definition above has facilitated the critical evaluation of the open spaces in terms of microclimate comfort indexes (PMV, PET) as well as a clearer distribution of critical areas. The synergy achieved among simplified visualization, interaction of the results and the built environment has improved the identification of vulnerable areas by promoting a deeper understanding of comfort perception surveys

(19)

The algorithmic and parametric approach has been implemented with additional GH components able to estimate, in accordance with current regulations on the reduction of the impact housing and the biotope area factor, two indicators (RIE11_{, BAF}12_{) to assess the permeability of soils and the “ecological}

value” of urban study area.

The control phase of the project has provided the opportunity to verify, theoretically, the “resilience” of the current scenario in terms of potential temperature13_{(POT. T.) to be able to compare, subsequently,}

the results obtained by the proposal actions (Figure 6 a).

Strategy and Project

Two operational strategies, a smaller one – “soft” – and a more decisive one – “hard” –, have been set up. The difference between them essentially depends on the quantity and quality of the surface solu-tions assumed according to the objectives: green surfaces and not-green surfaces, adopted tree species and technological surface solutions (such as the technical ones reported in the RIE document). Thanks to the virtual interaction, the designer maintains full autonomy in the choice of tree species and in the

Figure 5. Microclimate simulation – exchanging data and analysis by RH+GH. (a) Natural ventilation map; (b) Grasshopper definition; (c) Computation cells detail.

(20)

(21)

displacement of them within the areas exposed to excessive radiative heat stress (Figure 7 - Figure 3 (a) and (b) in Ambrosini, L. & Bassolino E., 2016).

As the urban design requires, the installation of canopies, steady and suspended, has been neces-sary to improve comfort and functionality of the open space to face the radiation shortwave. The best configuration of the canopies has been the outcome of form-finding operations implemented in RH + GH environment especially in local market areas such as via Annella di Massimo, Via G. Rossini and the entrance of Borgo Antignano, as shown in Figure 8.

(22)

Thermal-Perception-Driven Adaptive Design for Wellbeing in Outdoor Public Spaces Figure 8. Parametric approach to the conceptual model of the tensile structure

(23)

At the end of the analytical phase, the current scenario scored the following results (see Figure 6 a): • Impact of building Reduction Index, RIE=1.94 (open space only), less than the minimum required

of 4.00 caused by the poor permeability of the soil. The percentage of the green areas is 8% (ap-proximately 1700 m2_{), while the equivalent area of planted trees is equal to 465 m}2_.

• BAF (ecological value) =0.24, less than the minimum required of 0.30; ecologically effective area is 4900 m2_{; total land area is 20200 m}2_.

• Climatic comfort indexes (Figure 8 a) describe high summer heat stress: PMV = 4.39 equivalent to

PET_max = 42.30 °C (theoretical Pet_Med = 29.30 °C).

• The IPCC 2050 scenario, returns a potential summer temperature of 29.92 °C (before action plan-ning), so a strong thermal stress perceived.

The experienced methodology expresses its effectiveness in terms of effect in decision-making to be able to “inform” multiple information relating them to the established design objectives. According to the soft strategy benchmark, the following results have been obtained:

• RIE 4.23, an improvement of permeating capacity of soils. The 25% of green areas (+ 17% com-pared to the current scenario) equal to 6300 m2_{. The equivalent area of planted trees is 2200 m}2

(+1600 m2_{compared with the current scenario).}

• BAF 0.28 excluding actions on buildings. However, the option to estimate a minimum percent-age of action by considering roofs as green-roofs (the GH definition includes green-roofs option) makes possible a positive feed-forward compared to objective strategies; ecologically effective area is 7658 m2_{; total land area is 25500 m}2_.

• Microclimatic comfort improved, PMV = 2.55, equivalent to PET_max = 32.80 °C (theoretical Pet_Med = 26.00 °C), thus the design benchmark is verified.

• Potential temperature PotT_max = 27.88 °C. From a level of “strong” physiological stress descends to ” moderate” level.

Improving dynamically the technological solutions adopted, the hard strategy maximizes the project objectives. The achieved results are (Figure 6b):

• RIE 6.67, an excellent value as expected by the relative legislation. Green areas 50% equal to 12850 m2_{(+ 25% compared to the soft strategy, + 42% compared to the current scenario). The}

equivalent area of planted trees is 3125 m2_{(+ 925 m}2_{compared to the soft strategy, + 2660 m}2

compared to the current scenario).

• BAF 0.31, the ecologically effective area obtained is 7940 m2_{(+755 m}2_{compared to the soft}

(24)

• The level of stress perception is “comfort-mild thermal stress”. In fact, the PMV = 1.99 is equiva-lent to a PET_max = 28.90 °C (theoretical Pet_Med = 24.00 °C).

• The potential temperature PotT_max = 27.32 ° C.

The results confirm the validity of the methodological process and compliance with the objectives fixed in this study, with the possibility to define the basis for future developments and expand the research objectives. Moreover, it is essential to implement the information of the specific microclimatic condi-tions, through instrumental monitoring in situ (thermography, moisture psychrometer, IR thermometer, anemometer, etc.) in order to obtain analysis from simulations closer to real conditions. (Ambrosini & Bassolino, 2015)

The aim of the authors is to replicate in the next future the procedure as described above for differ-ent physical and morphological city features to better describe currdiffer-ent and proposal strategy scenarios.

THIRD CASE STUDY: FROM THE OUTDOOR SPACE TO THE INDOOR

EFFECTS - A PARAMETRIC SIMULTANEOUS SIMULATION METHODOLOGY

FOR THE DEFINITION OF CLIMATE ADAPTIVE DESIGN SOLUTIONS

The current phenomena of Climate Change are having increasingly growing impact on the urban as-sets. The Urban Heat Island effect in particular, depending on morphological and material conditions of the urban assets, affects the local microclimate, determining risks for people who live in the areas. These phenomena have much greater effects in the contexts of southern Europe, characterized by higher temperatures and often by overbuilt urban context, generating variation of the local microclimate and growing increase of the temperatures which determinate bad conditions of thermal comfort of the users, both in the outdoor and the indoor environments. If on one hand the effects of the current Climate Change are perceived more in the outdoor than in the indoor environment, on the other hand they have conse-quences also on the inner built space, where people spend more time and which are often characterized by technological and architectural conditions unable to hinder the current thermal and environmental changes. Moreover, it is the outdoor space itself that generates consequences on the indoor one, so that in addition to the effects coming from the bad construction of the buildings there are the ones produced by material and morphological conditions of the outer asset.

The current research in the field of Environmental Design is based on the use of advanced informa-tion technology tools which provide the definiinforma-tion of Climate Adaptive Design soluinforma-tions to mitigate the effect of the current Climate Change phenomena. These researches have been conducted both on the outdoor and indoor environments, using different tools and methodologies, producing considerable results in term of analysis and affordability of the defined solutions. Although there is still shortage of surveys and tools aimed at investigating the microclimatic relation between indoor and outdoor space, not only in qualitative but also in quantitative terms.

While it is known that an improvement of the outdoor thermos-hygrometric conditions ensures an improvement of the indoor conditions, few research works aiming at establishing not only the qualitative but especially the quantitative relation between outdoor and indoor environments have been conducted.

(25)

The only significant case in this filed is the research An outdoor-indoor coupled simulation framework

for Climate Change–conscious Urban Neighborhood Design, of Chengzhi Peng and Amr Elwan of the

Sheffield University, where, “Utilizing two existing software systems, ENVI-met for urban neighbor-hood outdoor simulation and Ecotect for building indoor simulation it has been demonstrated “how a workflow can be implemented to play out climate change scenarios on urban neighborhoods and the buildings located within” (Peng & Elwan, 2014).

On the other hand, the possibilities offered by parametric based software (Grasshopper 3D and its add-ons in particular) allow the users to simultaneously work with different variables and outputs coming from different simulation models in an unique virtual work environment, guaranteeing the monitoring of the data concerning different environments, such as the indoor and outdoor spaces.

Thus, the following research aimed at defining a methodology that, making use of appropriate informa-tion technology tools, and taking in account the interoperability of their outputs, ensure a simultaneous monitoring between different parametric software environments and the determination of the quantita-tive and qualitaquantita-tive impact that the outdoor environmental conditions produce on the indoor comfort. The described methodology has been then applied to an urban redevelopment project of the Duchesca district in Naples, showing how climate adaptive design solutions directed to contrast the Urban Heat Island effect in the outer urban space ensure a simultaneous improvement of the outdoor comfort and the indoor comfort in the surrounding buildings.

The following research project started by considering the results of the previous above mentioned research (An outdoor-indoor coupled simulation framework for Climate Change–conscious Urban

Neighborhood Design), analysing chosen urban neighbourhood context by using the three-dimensional

(3D) prognostic micro-climate model ENVI-met, developed by Michael Bruse and team at the University of Mainz. However, trying to overcome some possible weakness of the previous mentioned methodol-ogy and in order to accelerate and making the whole process parametrically based, the resulting data of the simulated microclimate have been used for indoor simulation of a parametric model in the virtual workplace made up of Rhinoceros 3D and Grasshopper’s plug-ins Ladybug and Honeybee, establishing an interoperability between the outputs of the different tools (Figure 14, Appendix 2). Hence, thanks to the newly defined workflow, on one hand it is possible to deduce quantitatively the effects that outdoor conditions produce on the indoor environment; on the other hand, it is possible to use the results of the conducted simulations to define adaptive design solutions for both the outdoor and the indoor space in the same virtual environment where the design process is conducted, overcoming the fragmentation of simulation and outputs.

Workflow

In the light of the above observations, the research was articulated in the following steps:

• 2D and 3D modeling of the study area in ENVI-met and Rhinoceros 3D and definition of a para-metric model for the environmental analyses through the graphical algorithm editor Grasshopper 3D

• Outdoor microclimate simulation in ENVI-met and evaluation of the analyses results • Extraction of the weather data of the outdoor environment from ENVI-met

(26)

• 3D and energetic modeling of the indoor environment in Rhinoceros and Grasshopper’s environ-ment, import of the weather data into Grasshopper’s plug-ins Ladybug and Honeybee and indoor microclimate simulation with Grasshopper’s plug-ins Ladybug and Honeybee

• Evaluation of the results of the simulations and definition of Climate Adaptive Design solution • Iteration of the process and evaluation of the results of the simulations

The chosen case study to which the following research has been applied is the Duchesca district of Naples, an area of the city of Naples between the UNESCO world heritage of the historic centre and the western city. The lack of green infrastructures and the dense overbuilding contributed to generate bad microclimate conditions and an increase of the temperatures in this area. A morphological and technologi-cal analysis of the area was a key point to understand the current criticises and to define a microclimate simulated model. The area was modelled using the cartographic documents of the municipality of Naples both in 2D and 3D through the computer aided design software Rhinoceros 3D. This three-dimensional model has been used for any kind of environmental simulation and to successively define the design solutions. In fact, the possibility to simulate the model through graphical algorithm editor Grasshop-per 3D integrated in Rhinoceros 3D (and in particular through the open source environmental plugins for Grasshopper Ladybug and Honeybee), not only to know the environmental behaviour of the area, but also to read the results of the simulations directly on the surfaces. Moreover, through the defined algorithm in Grasshopper it is possible to analyse and compare different simulation by differentiating the three-dimensional model in Rhinoceros, thanks to the interoperability between the simulation model and the simulation results. In this way, by using the same algorithm, it is possible to simulate the starting condition and the design solutions, comparing in the same virtual workspace the different results. In particular, the analyses about the solar incident radiation and insulation sunlight hours were performed on the model, based on the climate data of Naples in EPW format (EnergyPlus weather data).

Outdoor Microclimate Simulation in ENVI-met and

Evaluation of the Analyses Results

Simultaneously the area was modelled in the holistic microclimate simulation software ENVI-met based on computational fluid dynamics and thermodynamics. By setting up the Configuration and the Area Input files in accordance with the ENVI-met input requirements (ENVI-met 2011), it was possible to obtain large volume of outputs from the neighbourhood simulation that can be further extracted and visualized by the LEONARDO module included in ENVI-met. In particular, by reading the comfort indicator PMV, PET and MRT it was possible to understand the criticises of the outdoor space and de-lineate a situation of high summer heat stress. Due to the long time required by ENVI-met to simulate the area and the impossibility of providing environmental inputs regarding long period the 3th July 2016 was chosen as simulation period. Though the belief that any other day of the year would not have worse thermo-hygrometric conditions make the results of the simulation plausible.

In order to simulate the indoor environment, in ENVI-met, the ‘atmospheric receptor’ construct can be initiated to produce simulated urban micro-climatic conditions specific to the studied locations within the described input area. In particular, as already shown by Peng and Elwan, “by placing receptors around a specific building, […] one can actually generate localized weather data files specific to that building’s immediate outdoor surroundings” (Peng Elwan,2014). In this way, it is possible to generate

(27)

weather data which are directly influenced by the characteristics of the surrounding, despite the usual weather data produced by weather stations, which are often based on the environmental and urban con-dition different from the urban assets (Figure 15 see Appendix 2). In ENVI-met’s LEONARDO module weather data can be extracted in .dat format generating data tables of the environmental conditions of the simulated input area.

Through the interface of the Ecotect’s Weather Tool it is possible to generate from this data a weather file in WEA format by setting up some inputs. Finally, in order to use the generated weather data in the indoor simulation environment, this one has to be converted in EPW file though the EP LAUNCH module integrated in EnergyPlus.

For the indoor simulation, the building known as “Palazzo Kimbo” in Via Mancini, one of 1950s con-crete buildings surrounded by the analysed context, was chosen. Thanks to some surveys and cartographic documents it was possible to draw and model a type apartment of the chosen building. Simultaneously an energetic model of studied space was defined, by generating EnergyPlus based materials and constructions through the use of Grasshopper’s add-on Honeybee (which generates a bridge between the Rhinoceros/ Grasshopper environment and EnergyPlus itself). The definition of an algorithm has made possible to simulate the indoor environment and to read different kinds of comfort indicator, such as PMV, PET and MRT (Figure 9). The analyses conducted at the starting condition by using the previously generated weather data show a situation of high summer stress as consequences of the constructive characteristics of the simulated environment and of the environmental conditions of the outer space (Figure 10 a).

The possibility of working in a parametric based environment like Rhinoceros and the integrated add-on Grasshopper allow the user to define climate adaptive design solution which are directly related to the results of the conducted simulations. For example, by reading the points where incident solar

(28)

Figure 10. (a) Evaluation of the results of the simulations and definition of Climate Adaptive Design solution; (b) ENVI-met Outdoor Comfort Simulations at the post-design conditions; (c) Grasshopper-Honeybee Indoor comfort Simulations at the post-design conditions

(29)

radiation generates the worse thermal conditions on the surfaces of the analysis model, it is possible to define the areas where the green has to be increased. The possibility of simulating in the same working environment also the indoor space allows to define climate adaptive design solutions by using the same methodology both in the outdoor and the indoor space.

By considering the results of the simulation and by identifying the more critical areas, design so-lutions, with the aim of increase the outdoor thermo-hygrometric conditions, were defined. Without intervening on the indoor space, the previously described workflow was again applied. The new results show not only an increase of the outdoor microclimate, but also of the indoor one (Figure 10 b and c). The possibility of reading the comfort indicator related to the indoor space allows to understand the quantitatively increase that climate adaptive design solution for the outer environment generate on the indoor microclimate.

Iteration of the Process and Evaluation of the Results of the Simulations

By iterating the previous workflow for multiple design proposal, it is always possible to understand the increase of the microclimate both in the outdoor and the indoor space. Moreover, the possibility of working on multiple design solutions in the same working environment allows a reduction of the time simulations and a better understanding of the most efficient strategy.

The application of the defined methodology to the case of an urban redevelopment project of the Duchesca district in Naples shows numerous advantages in term of increase of the microclimate condi-tions and affordability, where a unique design strategy conducted on the outdoor space allow also an increase of the indoor condition of the surrounding buildings (Figure 11).

Figure 11. Evaluation of the result and increase of the comfort conditions both in the outdoor and indoor environment

(30)

DISCUSSION

The defined simulation processes and the obtained results following the simulation processes show the efficacy and the evolution of the methodology used, as well as the possibility of obtaining results to define sets of solutions to state guidelines to orient designers and administrative bodies towards a climate adaptive design approach to design the urban space.

The three case studies analysed, have shown a significant improvement in urban thermal comfort (about -50% of reduction considering PMV values) and that the consequent reduction in summer air temperatures above 2 °C is possible through a spread urban regeneration and differentiated approach, according to the context of application (historical, modern or contemporary).

Generally, and where possible, the design actions which contribute in terms of temperature reduction and to improve outdoor thermal comfort, with benefits to indoor comfort, are represented by: 1) the use of green, such as trees, flowerbeds, lawn areas, etc., which in addition to the increase in shading to reducing the incident temperature (see. Nouri, 2015), enhance ground evapotranspiration phenomena by lowering air temperature; 2) replacement of urban surfaces with ones which have an albedo factor between 0.40 and 0.60, that balance the performances in terms of temperature reduction and perceived thermal comfort (see Givoni, 1998; Zinzi 2013; EPA, 2008), and can be distinguished depending on the contexts and the urban morphology (in areas with an SVF values between 0.60 and 0.80, the albedo of pavers should be between 0.40 and 0.50, while in areas with an SVF values between 0.40 and 0.60, the pavers should have an albedo between 0.50 and 0.60); 3) the use of shielding systems, fixed or mobile, which are able to reduce the summer heat load on urban surfaces, by ensuring shading in those parts of the city where it is not possible to intervene through the use of vegetation.

The methodological evolution in the simulation processes of the urban environmental conditions has thus allowed to reach the intended starting point, namely the creation of a data exchange platform between different softwares, capable to investigate the issues of today’s outdoor comfort and in climate change conditions, and to evaluate the contribution of urban regeneration actions to the indoor comfort.

The study of the microclimatic response of some parts of the city of Naples and the assessments of adaptations action in response to high summer temperatures in cities and the phenomena related to future climate change may, and should, intercept the interest of municipal administrative bodies in order to guiding them towards decision-making widespread processes of urban regeneration, capable of respond-ing adequately to the problems associated with high urban temperatures. Appropriate and differentiated sets of adaptive design solutions must be prepared and suggested to the municipal administration based on the analysis of the physical and morphological characteristics of the different urban contexts of the city. Special attention should be paid to define the most suitable solutions for those parts of the city that are subjected to architectural and landscape constraints by the safeguard administrative authorities.

CONCLUSION

Most analysis about the meta-project concerned the study of intervention strategies aimed at improving any form of microclimate wellbeing and the effects of adoptable solutions in terms of interaction between end-users and the built environment.

(31)

The attention given to the open spaces can be understood as an element within the nodal role that cities are taking on a global vision. They are the most exposed places to very tangible effects that natu-ral phenomena, generated by climate change, are giving to the built environment, the economy and the society, too. These changes are reflected in everyday life and in the way of “living” urban spaces.

Careful environmental design must never forget that in the futile future phenomena such as heat waves, the alteration of rainy weather and the disadvantages due to urban heat island effect, will be a constant of the design process and it will be necessary to confront and interact with it through methodological rigor.

It becomes necessary to define those actions and technical solutions for adaptation and mitigation for climate risk management, useful to be adopted for the design of buildings and urban outdoor spaces: • No-Regrets: Those that will pay off immediately under current climate conditions;

• Low-Regrets: Low-cost policies and measures that have potentially large benefits. These should be identified as early as possible in the design process, to maximize opportunities and minimize costs;

• Win-Wins: Policies and measures that help manage several climate risks at once, or that also bring other benefits, such as complementary reduction in GHG emissions;

• Adaptable, flexible and resilient policies and measures, so places can adapt to a continually chang-ing climate. (see Shaw et al., 2007).

The result achieved, in terms of strategies, actions and interoperability results from design simula-tion environments to consultative/representative ones, is driven by the logic of process digitizasimula-tion. The achievement of the project objectives, as well as the representation of the open space as close as possible to reality, remains possible only if experimentation and simulation (in the sense of representation through shared codes) will tend to be customizing the potential solutions in the next future. The phases of deci-sion making in environmental assessment processes will be increasingly built to address the peculiar characteristics of the analysed study context if carefully “informed and modelled”.

The platforms for the Digital Design, broadly, represent an ideal virtual development environment in which the phases of decision and management process, [...] constitute places to manage complexity. (Chiesa, 2015. Trans. by authors)

The need to manage multiple streams of information, direct (measured in situ) and indirect (simulated by software), gave rise to the possibility of improving certain management aspects of environmental design process not only in the performative sense, but also assisting in decision making.

The direct result of this “complexity” is changing rapidly the role, the competence and the respon-sibilities of all building industry operators who, from the local level to the global one, will tend to be increasingly involved in more and more data driven and shared processing oriented projects.

Pending specific regulatory instruments, architecture, through the ability of designers and research-ers, will have to propose innovative solutions and design processes that can cope with events that are changing the world and the human life.

(32)

REFERENCES

Ambrosini, L., & Bassolino, E. (2016). Parametric Environmental Climate Adaptive Design: The Role of Data Design to Control Urban Regeneration Project of Borgo Antignano, Naples. Procedia: Social

and Behavioral Sciences, 216, 948–959. doi:10.1016/j.sbspro.2015.12.092

Anderson, K. (2014). Design energy simulation for architects. New York: Routledge.

Dessì, V. (2010). Progettare il comfort urbano. Soluzioni per un’integrazione tra società e territorio. Napoli: Sistemi Editoriali Esselibri.

Dessì, V. (2015). La progettazione bioclimatica degli spazi urbani. REBUS® - REnovation of public

Buildings and Urban Spaces, 4(1), 1-20.

EPA - Environmental Protection Agency. (2008). Reducing Urban Heat Islands: Compendium of

Strate-gies Cool Pavements. EPA.

Fanger, P. O. (1982). Thermal Comfort. Analysis and Application in Environment Engineering. New York: McGraw Hill Book Company.

Fitch, J. M. (1980). La progettazione ambientale. I caratteri ambientali dell’architettura. Padova, Italy: Franco Muzzio Editore.

Givoni, B. (1998). Climate Considerations in Building and Urban Design. New York: John Wiley & Sons. Höppe, P. (1999). The physiological equivalent temperature – A universal index for the biometeoro-logical assessment of the thermal environment. International Journal of Biometeorology, 43(2), 71–75. doi:10.1007/s004840050118 PMID:10552310

IPCC. (2007). Synthesis report: summary for policy-makers 2. Retrieved July, 2015, from https://www. ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf

IPCC. (2013). Climate Change 2013: The Physical Science Basis. Summary for Policymakers. Technical

Summary and Frequently Asked Questions. Retrieved July, 2015, from https://www.ipcc.ch

IPCC. (2014). Climate Change 2014 - Mitigation of Climate Change. Cambridge, UK: Cambridge University Press.

Losasso, M., & D’Ambrosio, V. (2014). Progetto ambientale e riqualificazione dello spazio pubblico: Il grande progetto per il centro storico di Napoli sito Unesco. Techne: Journal of Technology for

Archi-tecture and Environment, 7, 64–74.

Matzarakis, A. (2015). Città e cambiamenti climatici, il progetto del benessere termico nelle aree urbane per l’urbanistica e l’architettura. REBUS® - REnovation of public Buildings and Urban Spaces, 3(1), 1-16. Matzarakis, A., Mayer, H., & Iziomon, M. (1999). Applications of a universal thermal index: Physi-ological equivalent temperature. International Journal of Biometeorology, 43(2), 76–84. doi:10.1007/ s004840050119 PMID:10552311

Mayer, H., & Höppe, P. (1987). Thermal comfort of man in different urban environments. Theoretical and Applied Climatologyl, 38, 43–49. doi:10.1007/BF00866252