Energy Performance Assessment of Historical Buildings CFD Simulations of Scirocco Room

Energy performance assessment of historical buildings CFD simulations of Scirocco Room

Relator Prof. Fabrizio Leonforte

Author Lea Kazazi 878007 Mirko Vilei 900105

Index Introduction ...... 3 1. Numerical simulation to investigate the adequacy of historical buildings ...... 4 1.1 Natural ventilation and computational fluid dynamics ...... 4 1.2 Possibilities and limitations. CFD vs BES ...... 5 2. Fluid simulations in heritage science ...... 8 2.1 Computational fluid dynamics in historical building: state of art ...... 8 3. Ventilation and historical buildings: three case studies solved with CFD ...... 17 3.1 CASE STUDY I ...... 18 3.2 CASE STUDY II ...... 21 3.3 CASE STUDY III ...... 24 4. Forerunner cooling systems: scirocco room ...... 28 4.1 History and typology evolution ...... 28 4.2 Examples of scirocco rooms ...... 30 4.3 Defining the case study ...... 34 5. CFD modelling ...... 39 5.1 Setting simulations and control volume definition ...... 39 5.2 Setting Data ...... 40 6. Results and Discussion ...... 43 6.1 Graphs ...... 43 6.2 Best Configuration and best Month ...... 53 6.3 PMV e PPD ...... 60 7. Conclusions ...... 66 ▪ Appendix ...... 69 ▪ References ...... 76

Introduction

Natural ventilation is the best system to be provided to historical buildings as a passive cooling. In this thesis the Scirocco Room of Villa Naselli-Ambleri has been analysed [1].

The system has been modelled and simulated through a pseudo-transient simulation on Ansys Fluent. CFD analysis is a very powerful tool to read and understand this kind of systems.

The knowledge of such a construction and operating principles is particularly important to re-discover the forgotten “places of delight” that are a fundamental element in Palermo history and culture.

Furthermore, preservation and reuse of surviving rooms represent a useful way to understand a simple passive cooling system whose principles could be reproduced in a contemporary way in modern buildings intended for a valid and functional energetic control.

1. Numerical simulation to investigate the adequacy of historical buildings

Some architectural structures inside historical buildings are often interpreted as cooling systems. The problem is the knowledge about the real functioning of these systems during the past and at the present. Usually they have gone through a lot of changes. Full scale measurements can provide data on ventilation rate, airflow distribution, mean air velocity around and inside a building, but these experiments are expensive and time consuming.

So how can we study these systems? Through CFD.

CFD techniques allow to study large confined spaces, where it is difficult to predict the indoor air flows and thermo-hygrometric fields by means of simplified models or measurements. Thanks to their features, CFD software, originally used only for scientific research, have become, in recent years, a design support tool used by professional engineers when an in-depth knowledge of indoor air flow paths and pollutants distribution is required.

Though, one of the hardest tasks of modelling is to obtain a reliable model but, once achieved, it can be a flexible tool that can be combined with experimental data to provide useful information on indoor airflow patterns. 1.1 Natural ventilation and computational fluid dynamics

In these years, there has been extensive research dealing with CFD modelling of natural ventilation in buildings, probably because this ventilation is seen as a sustainable solution to reduce energy consumption and retain healthy conditions. However, there is the need of better addressing the effectiveness of natural ventilation in historical buildings and its implication in heritage preservation. Because of the monumental value of historical buildings, every intervention or refurbishment that can modify the indoors has to be carefully planned with the priority of conservation. This is because artworks have been adapted to a natural microclimate over centuries, gaining an equilibrium able to compensate cyclical seasonal variations in temperature and relative humidity. So, in these buildings, conservation should be a priority in the evaluation of indoor conditions. If adequate, a natural microclimate, to which artworks have been adapted over centuries, should be maintained to avoid sudden microclimatic changes and consider the main features of the site. This is why, at the stage of air-conditioning system design or retrofit, it is extremely important to carry out a series of preliminary analysis to evaluate and monitor the existing environmental conditions and to anticipatory simulate and predict the post-intervention conditions. In particular, the estimate, in “predictive” terms, of the microclimatic parameters and of their space distribution is becoming essential in order to define the compatibility of the environment with the maintenance of the desired conservation conditions.

Consequently, natural ventilation is generally preferable for conservation reasons, and insulating the external walls might be avoided. In natural ventilated systems the airflow is driven through ventilation openings by the natural driving forces of wind and temperature, therefore a comprehensive understanding of complex airflow patterns linked to wind effects and buoyancy is essential.

1.2 Possibilities and limitations. CFD vs BES

CFD simulation have the potential to predict the situation that is going to happen inside the volume analysed. As introduced before one of the hardest tasks of modelling is to obtain a reliable model but, once achieved, it can be a flexible tool that can be combined with experimental data to provide useful information on indoor airflow patterns.

The main steps to follow in a CFD investigation procedure are here summarized:

• definition of the geometrical model; • characterisation of the air flow opening/devices and of the internal gains (heat, pollutants, etc.); • definition of the boundary conditions and adoption of a turbulence model; • discretization of the calculation domain; • run of the numerical simulation and verification of the numerical convergence; • analysis of the results (air flow path, velocity fields, thermal fields, etc.).

In general, In CFD models the equations of conservation for mass, momentum (expressed by the Navier– Stokes equations), energy and chemical species, together with the turbulence models, are written and solved. In particular, the partial differential equations ruling the system are discretized in terms of finite differences and solved in a given number of points of a grid overlapped to the geometrical domain. The discretization approach adopted for the air distribution analysis is typically that of the finite volume method. Alternatively, the finite element method is used. To define the volume in which the boundary conditions will be set, it’s always suggested to simplify the forms, so from a slightly trapezoidal plan, is preferred to take an equivalent rectangular shaped one. This will be carefully described in the Case Study of Palazzo Madama (Turin)[2].

Often The aim of CFD simulations is to improve the thermo-fluid-dynamic behaviour by modifying as less as possible the existing configuration. To do this, the boundary conditions and the inlet and outlet features should be set carefully, recreating an indoor environment as close as possible to reality. One of the strongest point of CFD simulation is the possibility to create all the different configuration in which the building has evolved during the time. This feature will be there after deeply discussed in this thesis. As it happens for the Scirocco Room, it doesn’t mean that the latest (most recent) configuration is the best one.

CFD simulation is also very useful because the simulation reduces time and cost in comparison with experimental measurements and monitoring campaigns and can provide results (parameters) that sometimes are quite hard to get/measure. Usually is preferred to run the simulation in ‘FREE-FLOATING’ and then to add or to make comparison with the simulation that takes in account the existing/future equipment.

Through CFD simulation experimental datas were confirmed: the natural ventilation system functioning guarantees an adequate internal air movement and cooling effect. The airflow (in terms of temperature or velocity) is immediately perceived when the distribution is homogeneous (symmetric).Though, not only for the of the Senato Room [2] but also for the cellar of the Marchese Building [3], phenomena like stagnation of cold/hot air is immediately shown and clearly identified with CFD outputs.

One of the possibilities of CFD is that, even if the model can be kept quite easy, surface-mounted obstacles (such as trees, or other buildings) can be included implicitly in the computational domain, by increasing the surface roughness[4].

figura 1 The concept of roughness

figura 2 The two different type of roughness

Actually, CFD works through the definitions of two different types of roughness: the aerodynamic one, and the equivalent sand-grain one. Which is the one to be considered depends from the scale of the object that is going to be analysed. The aerodynamic roughness (zo) works and define large-scale terrain, while the other one (ks) defines small-scale surfaces [5].

In general CFD it has to be considered more versatile then BES (Building Energy Simulation) because, while CFD is applied for both the indoor environment of the buildings and the outdoor one, BES keeps the focus on the internal situation. Both CFD and BES are able to predict indoor environment, but they move on different fields.

figura 3 Microscale and building scale. The limit of the domain define the program to use

Thats why CFD is suitable to be used also in urban scales[6], instead of BES that is able mainly to work on residential one. This is clear when once the domain of the model is settled. On the contrary, if the attention is focused on Internal Gains, the choice of BES simulation is more suitable than CFD. Its vey hard through CFD to insert the OCCUPANTS and their behaviour. For this reason, once the output temperatures were obtained inside the Wind tower of the Scirocco Room, they were evaluated as more or less comfortable through the comfort index of PMV/PPD. Some other limitation of CFD are some feaures not included and quite difficult to recreate in the model such as the cloud formation or precitation, or even atmospheric radiative characteristics.

In the model of the Scirocco Room, since the Irradiance plays a foundamental role inside the comfort of the wind tower and activate its primary function, we calculated it a part and inserted as a surface temperature of the element. Of course it was considered different if the surface was vertical or horizontal.

Another example is given by the RH. CFD is not able to give directly this information, thus if is needed to be defined the thermo-hygrometric features of the mass flow-rate in that particular istant, they have to be derived as described in the case of the study of the crypt of the Lecce Cathedral [7]. For sure the versatily of the CFD modelling has to be taken in account. CFD approach can be also adopted in other cases where the microclimate can vary significantly in function of different air inlets. So, once the model is settled, just by changing the air inlets (like in the example of the Senate Room[2]) we can come with completeley different configurations.

Though, another limitation of CFD simulation should be underlined. For CFD simulation, in particular for 3D model simulation, difficulties in achieving convergence are quite common. For this reason, application of CFD to simulate long time periods (e.g.months to years), with changing boundary conditions, can become prohibitively expensive, BES in this case is better. CFD simulation will finish just when the simulation will reach the convergence. Usually is set a termination threshold of 0.001, that indicates also the accuracy of the result of the output of the model. But sometimes, the system can be trapped in oscillatory convergence. Usually, the natural ventilation flow, falls into this kind of convergence, because it recalls the modes of the actual transient behaviour of the natural ventilation flow[8].

figura 4 Oscillatory convergence

In general, if there is a need of a clear output, in each point of the system and a clear behaviour of the streamline of the mass flowrate of that system is better to use CFD, otherwise BES is enough. Recent studies have come up with the idea that to have the best indoor quality prediction, both BES and CFD should be used. BES will cover the doubts related to the occupancy and the thermal behaviour of the building yearly in terms of heating load or cooling load, while, to understand better the efficiency of the system itself, and to verify how much homogeneous is the flux of air inside of it, the model should be defined thorough CFD analysis.

In this thesis, the model was all performed through CFD analysis. BES hasn’t been taken in account. This choice has been done, since the peculiarity of the building is the building itself (as a natural cooling system). From an historical point of view, it was clear that people used to gather in the Scirocco Room to have much more comfort, but how this comfort was created is the real aim of this research.

Because of this it is important to understand how the mass flowrate moves inside the system and since the system is composed by different elements (Wind Tower, Tunnel, Sorgiva, Sorgente) how do each element acts and its related to the other one.

2. Fluid simulations in heritage science

Computational fuid dynamics (CFD) involves the calculation of fuid fows and their interaction with solids. Most historic materials are surrounded by a fluid, mostly air, in rare occasions water, sometimes a solid with a certain water content. It is widely acknowledged that air transports many of the agents of deterioration of concern for preventive conservation: heat, water in vapour phase, aerosols, spores and gaseous pollutants. So fluid dynamics is the scientific discipline that studies flows.

It was first applied to buildings and then to historic buildings, with some delay: the oldest paper cited in this review dates back to 1999[9]. The use of CFD in historic buildings is preceded by the use of building energy simulations.

Figura 5 BES vs CFD

Its application in ordinary buildings as well as those in the cultural heritage sector was reported at a Building Environmental Performance Analysis Club Seminar, RIBA London on 9 June 1994 by May Cassar in “Design Criteria for the Museums and Galleries Environment”. This report identified the challenges and opportunities of simulation and described building projects that included simulations of energy and moisture transfer that were realised for organisations. The design advice included new totally passive museum buildings as well as the refurbishment of many existing museum buildings with conventional HVAC (Heating, Ventilation, and Air Conditioning) systems that were seeking to evaluate environmental performance options.

Since then, the number of publications and applications has been rising steadily. Even though fuid dynamics has been used notably in the field of heritage, there has not been until now any attempt to review the existing research. There have not been, in fact, any events, conferences or other academic initiatives that could act as fora for the definition of a shared research agenda.

2.1 Computational fluid dynamics in historical building: state of art

Te intent of CFD simulations in heritage is diverse. It has been identifed three loose categories of simulations according to their purpose. Firstly, we find the simulations that aim at obtaining a visualisation of air flow in an environment. Secondly, there are simulations that provide evidence for the historical interpretation of a site. Finally, there are simulations intended as an integral step of a design process, a conservation project or, more generally, that support decision-making. In all of these three categories it’s easy to be found signifcant technological innovation, even though advancing the state of the art in fuid dynamics is rarely the main research objective of the reviewed articles.

Type 1: Air flow visualisation

As a general rule, obtaining the air flow pattern is the main objective of simulations of this type. Conservation implications are not necessarily part of the research. The simulations may be a tool to generate a hypothesis. Here are shown some examples of this type.

figura 6 cit.[10]

figura 7 cit..[11]

figura 8 cit.[12]

figura 9 cit.[13]

figura 10 cit.[3]

figura 11 cit.[14]

figura 12 cit.[15]

figura 13 cit.[16]

Type 2: Simulations as historical evidence

This category uses the simulations as evidence to aid the interpretation of a site. The hypothesis or research questions are historical or interpretative and the simulation is used as additional evidence.

Here are shown some examples of this type.

figura 14 cit.[17]

figura 15 cit.[18]

figura 16 cit.[19]

figura 17 cit.[20]

figura 18 cit.[21]

figura 19 cit.[22]

figura 20 cit.[23]

figura 21 cit.[24] 12

Type 3: Simulations for preventive conservation

Finally, there are simulations that are used to support decision-making processes. These processes may consist of the design of ventilation systems, building layouts or urban plans and in some instances preventive conservation plans.

Here are shown some examples of this type.

figura 22 cit.[25]

figura 23 cit.[26]

figura 24 cit.[7]

figura 25 cit.[2]

figura 26 cit.[27]

figura 27 cit.[28]

Time representation

There are fundamentally three ways of representing time in CFD, each with several variants. Firstly, the simulation can represent an unchanging state that is true for a certain period that could be infinitely long, which is known as steady state. Secondly, we find pseudo-transient simulations, which represent a series of steady state scenarios that approximate a continuous variation, for example, winter and summer conditions or monthly conditions. In other words, time steps that are significantly longer than the time that the system takes to reach steady-state conditions.

Finally, there are transient simulations, which aim to resolve the equations for every time step of the evolution of the system.

Steady State Pseudo-Transient Transient

Any time period Experiment validation Costant BC

Papers: Papers: • 2 seasons:[9],[2],[29] • few hours:[33] • 3 seasons: [30] • half a day [34],[35] • constant conditions: [31] • or a day [10] • no time spain: [32], [11], [27]

figura 28 Table 1 Time representation

Visitors

The human presence is usally something difficult to try to simulate in a CFD simulation. Despite this, some researchers try to do that and try to create different form of human rappresentation in the model. In this table they are summarized. For sure the next step will be not identifing the human body just as a source of heat, but to also try to consider its movement.

figura 29 cit.[34]

figura 30 cit.[36]

figura 31 cit.[37]

figura 32 cit.[9]

figura 33 cit.[16]

Future investigations

In general its useful to say that simulation of fluid motion in heritage is predominantly concerned with air motion, particularly indoors it is observed that there are great similarities between the many published simulations: geometries tend to have a size between 10 and 50 m, the simulated fluid is typically air, mainly transporting thermal energy and humidity. The air motion is usually simulated as turbulent and k − ε is the model of choice to simulate turbulence.

And yet, despite this apparent homogeneity of objectives and methods, it seems unfitting to speak of this body of work as a well-defined scientific discipline. The reason may be that even if each publication is well aware of its scientific framework, they are not necessarily aware of each other. In other words, the simulations of heritage spaces emerge individually to resolve specific issues, but they do not share research questions or coordinate research efforts. However, many shared issues exist and they should become the basis of future investigations [38]:

• The time-scale problem. There is a miss-match between the time-scales that are usually simulated (from hours to months) and the long-term nature of processes of change. Simply put, hourly variations that cause damage over years cannot be realistically simulated with the existing CFD technology. Researchers approach this issue in many ways: using representative conditions for long periods of time, or simulating change during a few hours. However, research is needed to find the appropriate time-scale for the variety of issues of interest for heritage science.

• The need for validation. There is a need for more comparisons between simulations and real world data, collected in the simulated environment. The difficulties of this task in heritage environments are many: slow change, difficulty of monitoring, the uniqueness of the sites studied and their conditions. But there is scope for further research on the validation of CFD models. Firstly, since CFD aims at simulating the spatial distribution of a quantity, validations should also use spatially distributed data. Secondly, there is a need for the development of benchmark cases that can be used for the validation of models of a diversity of conservation issues, to be used when other types of validation are not possible.

• The low-turbulence problem. Velocities indoors are usually low (under 0.1 m/s) and sometimes air flows may not be fully turbulent. Even though the k − ε model seems to provide acceptable results, there needs to be a critical reflection on the use of turbulence models in indoor heritage spaces. Further research is needed in the assessment of the levels of turbulence found indoors and the methods to model it.

• The near-wall problem.The interest of heritage managers is not only on the value of transported quantities in the centre of rooms, but particularly on the value close to valuable surfaces. Despite the emphasis on the interaction between air and heritage materials, few published simulations include estimations of wall fluxes, such as evaporation or condensation of moisture or dust and gas deposition. This may be a valid assumption in many instances, but in any case it should be explicitly discussed. The implementation of such models will, additionally, require computational refinements close to surfaces that may differentiate heritage CFD models from other indoor simulations.

3. Ventilation and historical buildings: three case studies solved with CFD

To understand and to create our model in Fluent, we before analized some reaserch related to the ventilation in ancient buildings and the simulation of that through CFD. Three studies will be here taken in account. The way in which the physical problem is converted into 3d, the definition of the boundary conditions, the inlet and outlet variables have been applied in the Scirocco chambre thanks to what this studies have anticipated.

(1) In the first case study, situated in Palermo, an ancient cooling underground system is observed. This system is 3m underground, and there is also the presence of a qanat[3] . (2) In the second case study, in Lecce, the crypt of the cathedral is the subject of the study. In this case, the simulation was divided into two parts, considering the hot and the cold season[7]. (3) While in the third and last case study, situated in Torino at Palazzo Madama, the functioning of an HVAC system has been run through CFD. In this case, even if the reaserch deals with artificial ventilation, imposes the steps of the simulations exactly like in the case of the natural ventilation that has been considered before.

Each of this examples, in its own way, helps us defining the more suitable steps to describe the system of the Scirocco Room. The procedure through wich the examples have been analysed is diveded in 5 steps: the introduction, the definition of the case study, the measurement campaign, the Cfd modelling and finally the results and the discussion.

Here are shown the 3 case studies summarized.

figura 34 Summary case studies

3.1 CASE STUDY I Numerical simulation of ancient natural ventilation systems of historical buildings. A case study in Palermo [3]

In this paper, the airflow patterns, distribution and velocity and the air temperature distribution inside a historical building in Palermo (Italy) were investigated by a transient simulation. A three- dimensional model of the library room, actually used as book deposit, where an ancient natural ventilation system is operating, was investigated using a CFD tool during the hottest day of the summer of 2006 in Palermo. The simulation results are in agreement with the trends of air velocity and temperature of the experimental values measured during a test campaign.

The old Marchese Building is located in Palermo (Italy). The old building belongs to the Jesuit building complex of Casa Professa near the 16th Century Jesuit Church. The original arrangement of the 14th Century is not the present one: the building has been incorporated in others such as the Priory of the Jesuit Fathers and various surrounding buildings.The building analysed in this paper is the present site of the City’s Public library. In particular, the indoor space studied is the book deposit, with open shelving for the books but without reading zones, that can be considered a single high, small volume with compact structures and various zones.

figura 35 b_3D model of the ambient studied – the book deposit with the section plane

The ambient studied is rectangular with dimensions of 14m length, 6.5m width and 7.7m height. The south and north walls with about 0.6 m thickness face the Cloister and the inner courtyard of the building. The cellars are located 3m below the ground floor and have a wide corridor of 15.5m length and 1.8m width. These cellars in the past were mainly used as a warehouse for goods and 18 product workshop and sales outlet. In the ground, below the cellars, there is a qanat, an artificial cold-water course running into a ground tunnel connected to the ground tunnel system in Palermo. From the cellars, cold air is brought by the natural stack effect by a single large air duct (originally a tunnel system with three ducts was present) into the room, the book deposit, and any warm air from inside flows outside due to temperature and pressure differences. This duct has a rectangular section with dimensions of 0.80m×0.50m and of 1.30m length. Its inlet is placed on the roof of the cellars, adjacent to the south wall, and its outlet is placed at the base of one of the window – doors.

Measurements were performed in the room, the book deposit, using a multiple data acquisition device (Babuc instrument) with a multidata logger. The measured parameters are the mean airflow velocity and thermohygrometric quantities such as relative humidity, dry and wet bulb temperature. The Babuc was stationed in the centre of the duct.

The 3D model did not take into account the opened shelving with different paper materials (books and prints). The qanat system, the artificial source cold water course below the cellars, was not modelled. The ventilation system investigated, in which the space of the cellars connected to the library by a single air duct, as shown in the previous figure, was investigated. The initial conditions for this transient computation were obtained by running the simulation for 2 days before (172,800 s) assuming, for the initial indoor climatic conditions, a uniform internal air temperature of 25 ◦C and 50% of relative humidity, as usually suggested.

Computational time needed for convergence was 18 hours. The simulation results obtained follow the same hourly distribution of the air velocity and temperature provided by the experimental values measured during the test campaigns. The simulated temperature values at the outlet of the duct have the same trend but are higher than those measured experimentally, probably because of the qanat effect.

figura 36 Stagnation Phenomena: Velocity vs Streamline

These two lasts show the air movement inside the connected spaces (the cellars and the room), the turbulence air distribution and the regions where a recirculation flow occurred.

Moreover, the main pattern of internal airflow can be deduced: a stagnant layer was formed at the ceiling level and the air mixing was particularly slow. This stagnant layer is not stable moving very slowly downwards with time. Another factor, that must be considered, is the presence of a large 19 door–window near the duct inside the room. This produces a warmer zone that locally reduces the air velocity increasing the turbulence effect. The daily indoor air temperature simulated values are quite spatial uniform within the range of 25.1–26.2 ◦C: this is due both to the natural ventilation system connected to the stack effect of the duct from the cellars to the room, and to the thermal inertia of the massive building opaque envelope. The air inlet from a near garden-court into a tunnel system in the cellars of the building compensates the high external air temperature and humidity. Experimental and simulation results confirm the natural ventilation system functioning that guarantees an adequate internal air movement and cooling effect. The natural ventilation system studied ensures stable and comfortable internal microclimatic conditions with high summer external temperatures and solar radiation fluctuations. The cold air from the cellar, which is connected to the external ambient by three openings, is driven by the natural stack effect due to the thermal buoyancy through the single air duct in the floor into the room studied providing comfort without any HVAC device system.

3.2 CASE STUDY II CFD modeling and moisture dynamics implications of ventilation scenarios in historical buildings [7]

This paper deals with the development of a three-dimensional (3D) CFD model to investigate the adequacy of natural ventilation for the conservation of the Crypt of Lecce Cathedral. The purpose of the research was to get a reliable CFD model to reproduce possible ventilation solutions for the building. The model outputs were then used to study the moisture dynamics related to the different solutions. The model was then validated with on-site measurements to verify its ability to predict indoor conditions. Once the model met the specified validation criteria, the microclimatic conditions of five ventilation scenarios and twenty computational models were investigated. The aim of the most comfortable scenario should be able to guarantee a suitable microclimate with reduced fluctuations that can favour deterioration processes. With this aim, temperature and relative humidity spatial distribution was visualized for the scenarios, taking into account two outdoor wind directions in opposite seasonal conditions. Furthermore, the model allowed to assess the indoor microclimate before the walling over with bricks of two Crypt's windows during the last century.

The Crypt of Lecce Cathedral was built by the Normans in 1114 and it is located 3 m under the current ground level in the historical centre of Lecce (South Italy).

figura 37 Crypt Lecce Cathedral

The building is reachable from the above Cathedral by two stairways that directly connect the two buildings. The Crypt has a Greek cross plan symmetrical to a central axis with the nave and the double aisles divided into equal parts by 48 columns and 38 semi-columns which support a geometrical alignment of cross vaults. The masonry shows deterioration evidence in the form of white salt crystals efflorescence covering the walls, columns and the Baroque decorations. Wood artworks are located behind the main altar, two statues are in two small niches where there are also two smaller altars. All these artworks show conservation problems, such as flaking off pieces of painting layers and cracks in boards, planks and tablets. The Crypt is made of Lecce stone, a typical soft limestone, characterized by a high porosity (30% e 40%) and a high capillary rise coefficient (9.4e11.8 mg/cm2 s1/2). The stone is also renowned for the property of absorbing water rapidly and drying slowly. The standard highlights that it is very important to avoid relative humidity fluctuations for any object typology. Since the building is currently inaccessible to the public, it does not have air conditioning and the lighting system is almost always turned off, the microclimatic variations can be mainly ascribed tothe thermo-hygrometric exchange with the outdoors that mainly occurred through the windows. As regards the study site climatic condition, Lecce has a warm Temperate

Mediterranean climate characterized by non-rigid winters (average temperature 13 _C over the last ten years) and high aridity in summer (average temperature 30.3 _C).

figura 38 Lecce Cathedral Model

Experimental data were collected outside and inside the Crypt during the period from February 2011 to January 2012. Air (T) and surface temperature (Ts), relative humidity (RH) and airflow velocity (V) measurements were automatically recorded every 360 min by an appropriate instrumentation. An important water vapour contribution in the building came from the ground.

A roughness constant of 0.5 was used in the simulations. A pressure based standard k-ε turbulence model was adopted with absolute velocity formulation. As already pointed out, no radiation model was included in the simulations as the effect of solar radiation is negligible in the Crypt due to the particular position of the building and the shape of its windows that do not directly face the outdoors. Possible scenarios given by ventilation were analysed in correspondence to a combination of different outdoor climatic conditions and airflow inlets, which produced air layers moving at different temperature under the force of gravity acting on the density variations. The windows that link the building with the outside were usually open without considering the connected microclimatic effects. Moreover, two of them were walled over with bricks in the last century, causing microclimatic variations needed to be better assessed. Two prevailing wind directions (from north/north - west and south/south - east) were considered, leading the air into or out of the Crypt in a different way through each window. Because of this, two main seasons (wet from October to March and dry from April to September), corresponding to extreme opposite rainfall and thermal conditions, were considered, for a total five scenarios, and twenty computational models to be simulated. In the first simulated scenario, called (A), all the windows were considered open. The walled-up windows were supposed to be openable in order to investigate the Crypt's condition before the walling of the windows F.5, F.6. In scenario (B), the windows F.5 and F.6 were closed to reproduce the current microclimate. The windows producing a negative airflow for conservation were simulated as closed in the other scenarios. In the last simulated scenario, called (E), all the windows were closed. Due to the building's structure, the entrance through which the Crypt communicates with the Cathedral was always considered both as an inlet and outlet air source. The columns and other internal partitions (altars, statues, artworks) were considered adiabatic.

Moisture dynamics evaluation A steady state ss characterized by the balance of the water absorbed by capillary forces U and the water lost by evaporation E, Uss = Ess, was considered to quantify relevant moisture physical quantities. Average, minimum and maximum temperature and relative humidity values were derived for each scenario to calculate microclimatic gradients in function of the season and wind direction.

Considering that the Crypt is closed to the public and that people comfort is secondary in respect to conservation needs, scenario E ensured a more suitable microclimate with the lowest microclimatic variations and a reduced relative humidity compared to the other scenarios. This scenario permitted air exchanges only by the entrance from the Cathedral, which provided air replacement.

figura 39 Scenario E: the best one

This study was not aimed at decreasing RH parameter, that is usually done increasing ventilation, but to determine the most appropriate microclimate for conservation, considering the building's feature and the fact that it is actually closed to visitors. To retain a consistent temperature and humidity throughout the Crypt, all the windows should be kept closed with the main entrance open. This can also limit the airflow velocity, reduce the evaporation rate and the consequent salts crystallization.

3.3 CASE STUDY III CFD application to optimise the ventilation strategy of Senate Room at Palazzo Madama in Turin (Italy)[2]

The present work aims at showing the potential of CFD tools to predict air flow paths and thermo- hygrometric fields in museum indoor environments. A large exhibition area is studied in order to identify an alternative solution for more suitable ventilation strategy and microclimatic conditions in the environment, without changing the position of the air inflow devices. Since the aim of the research was to optimize the ventilation strategy and the air distribution, only thermal and flow fields have been analysed and compared, and the effectiveness of the proposed improved solution has been demonstrated. Construction constraints were such that it was not possible to change the position of the air inlet devices and the only applicable improvement was to change shape and direction of the primary air supply jets. The research activity has consisted of a detailed analysis of the total air flow paths and velocity/temperature fields inside the room, during both heating and cooling operating conditions. Different solutions have been tested to optimize the primary air distribution. Indoor air flows and the thermal fields were simulated, and the resulting environmental conditions were compared. The effectiveness of the proposed optimal solution was, finally, proved.

The fluid-dynamic simulations were aimed at analysing the air distribution and the environmental conditions in the Senate Room, a large-sized exhibition space in Palazzo Madama – Turin (Italy)

figura 40 Palazzo Madama (Turin) view

This room is parallelepiped-shaped, with a base of 18.6 m×23.5 m and a height of 19 m. The HVAC system consists of a primary air system coupled to fan-coils. The primary air is supplied thorough seven air inlet devices located near the ceiling, just above a cornice, with an inclined flow direction, as shown in figure.

figura 41 Air inflow devices position: previous solution and ameliorative solution (plan view/vertical section).

Moreover, inside the room, there are 12 fan-coils homogenously distributed on the sidewalls and located at floor level, which provide both heating and cooling.

The Senate Room was modelled as a parallelepiped enclosure with a size of L(x) = 18.6 m, W(y) = 23.5 m, H(z) = 19 m. Compared to the actual shape of the room, which is slightly trapezoidal, the model adopts an equivalent rectangular shaped plan.

figura 42 Senate Room: model

The figure shows the geometrical model of the room with the location of the air inlet openings and fan-coils. The geometrical domain has, then, be discretized subdividing the sides of the parallelepiped as follows: L(x) = 54 segments, W(y) = 49 segments, H(z) = 33 segments; this corresponds to a computational grid of over 87,000 structured cells. The air inlet devices and the fan-coils have been positioned in the same points as they are in the actual design. They were simulated by means of fixed air velocity boundary conditions (that is specifying air speed, air flow direction and local turbulence quantities- turbulence intensity and equivalent length of turbulence for the specific inlet device). Primary air was extracted, through rectangular openings at the floor level. For both the primary air and the recirculated air from the fan coils, the boundary conditions were chosen so as to provide in the model the same value of the actual air flow rate and air speed of the Senate room (this meant to create a model in which the size of the air inlet devices match that of the actual design. Therefore, the boundary conditions refer to the design specifications). The temperature of the primary air introduced through the air inlet devices and the fan-coils, in both winter and summer operating modes, and the surface temperatures of the building envelope components (identified in the floor, ceiling and walls) were assumed equal to the nominal design values. The internal heat gains during the summer period have been modelled as a uniformly distributed load over the floor (fixed heat flux boundary conditions). The resulting total thermal loads (corresponding to about 33 W/m2 for heating and 77 W/m2 for cooling) are balanced by the thermal powers generated by the mixed system “primary air and fan-coils”.

figura 43 Boundary conditions

Some of the simulation results are graphically resumed in the figures below, where the streak lines (showing the main air flow path inside the Senate Room), the velocity fields and the temperature fields are shown. Flow and air temperature fields are plotted over a plane located at a representative height of 1.8 m above floor level. For the sake of brevity, only results related to the original (design) and the optimized (final, after retrofit) configurations are analysed in the paper. The sensitivity analysis, from which the optimal configuration has been identified, was based on a series of simulations performed by using the same ventilation system but by changing the direction (angle and tilt) of the inlet air jets. For the design configuration, the velocity and temperature fields reveal a non-uniform spatial distribution of the environmental parameters during both the heating and cooling operations. In particular, the flow field (velocity vectors are sketched) and streamlines, highlight that the supply air flow does not mix efficiently with the indoor air. The main air flow path, in fact, is confined in a small part of the room, near the lateral and front walls. The primary air jets reach the upper part of the opposite wall and then flow downwards, influencing the occupied zone only in a relatively small area located at the opposite side of the main entrance. This flow structure does not allow for an optimal exploitation of the ventilation air. Flow shortcuts between supply and exhaust air arise and a stagnation zone, characterized by low velocities, forms in the central part of the room.

figura 44 Cooling Mode. STAGNATION ZONE

The phenomenon is particularly stressed for cooling (summer) conditions where a zone with higher air temperatures is also highlighted. The fact that the air distribution performance is quite poor, will negatively influence the possibility of properly controlling the relative humidity, pollutant concentration and temperature levels inside the hall and of achieving optimal environmental conditions for the conservation. The final proposed ventilation system set-up allowed to find an improved solution for both the heating and cooling operation modes. It can be seen that, now, the primary air jets behaviour is similar to a “free air jet”, with the primary air flow falling “as a cascade” into the occupied zone.

figura 45 Cooling Mode. Symmetry ZONE

The degree of mixing is far higher than in the original solution and this leads to a better spatial uniformity of the air velocity and temperature. Both the flow and temperature fields reveal a reasonable symmetry along the longitudinal axis, without any relevant stagnation zone. The environmental parameters, despite the significant volume and height of the room, are sufficiently uniform. Therefore, such flow configuration will allow a better control of the temperature, relative humidity and pollutant transport and deposit within the entire space occupied by the exhibition, in both summer and winter configurations. The presented study did not deal with relative humidity field, but the uniform air and temperature distribution inside the room (well mixed ventilation strategy) allow to assume that it will be possible to satisfactorily control the relative humidity. A continuous monitoring of the indoor environmental parameters (T and RH) has been suggested and will be performed after the ventilation system renovation.

4. Forerunner cooling systems: scirocco room

Once the settlement typology and the technological were adequate to the different territorial realities. Scirocco room can be identified as bioclimatic archetype. A real model of integration between environment and human life. In the expressions of the pre-modern architectural culture of the Mediterranean area and in particular in the Arab-Islamic one, it can easily be read the attention to the cooling issues and passive ventilation that made the adaptation of human settlements possible in extreme environmental systems. In Palermo, when the already high summer temperatures were made unbearable by the hot African scirocco wind, (from the Arabic shurhùq), which it blows from the south-east, the heat was fought through wet bed sheets, placed at the windows that, drying in contact with hot air, released humidity and coolness inside the rooms. The thick house walls, built with the local limestone, contributed with their thermal mass, to protect the rooms from the excessive heat of daylight hours. Water, thermal mass and ventilation were therefore possible remedies to fight the heat.

4.1 History and typology evolution

In Palermo influences from Middle Eastern countries have left a deep mark, and it is really in the Arabic world and in particular to the old Persia [39] that the origins of the sirocco rooms took place. These are underground structures that draw inspiration from the sirdáb, term deriving from the Persian sard (cold) and ab (water); semi-underground environments provided with fountains, water mirrors or canals that cool and humidify the air.

figura 46 King Zoser's Stepped Pyramid and mortuary precinct. Saqqara, Egypt. Dynasty III, circa 2675-2625 B.C.

An ancient example of this structure was found among the ruins of the palace of the caliph of Damascus (724 AD), Hisham ibn ‘Abd al-Malik, in Archaeological site of Jericho.

figura 47 Hisham's Palace. Jericho, West Bank. 724-743

The sirocco rooms of Palermo are the prerogative of the local nobility and of rich gentlemen owners of the sumptuous villas of the suburbs arose around the eighteenth century during a moment of particular economic growth for the city. During this period many Palermitan families used to move to the country houses to spend the long summer months taking refuge in large artificial caves dug underground, below or near the houses, to escape the stifling heat of the sirocco days. The rooms, in fact, mainly in square or circular, they were isolated from the external environment because the thermal inertia of the calcarenite which allowed the room temperature to be kept constant underground.

Added to this room, usually there was the presence of water in the subsoil. The underground of Palermo is full of water network channels, called "ngruttati", like the qanat of Persian tradition realized during the Arab domination in Sicily. The scirocco chambers were thus preferably made where there was the crossing of a watercourse, natural or artificial, not much deep, in order to be able to intercept the passage of fresh water that evaporating contributed to the cooling of the air inside the cave. Moreover, the current of air generated by the flow of moving water pushed the heat, conveying it towards the top of the vault that covered the chamber and in which an opening was used to conduct hot air outside, also providing some light to the hypogeum. Once again, the architecture and technologies of the Islamic world find a wise application also in Sicily and the underground rooms of Iranian homes, ventilated through wind towers and cooled by the qanat are transformed into the "rooms of the scirocco" in Palermo.

The temperature of these environments, almost constant throughout the year, made these places ideal places for the preservation of perishable foodstuffs, thus also acting as primordial refrigerators.

4.2 Examples of scirocco rooms

Few researchers have been interested in these structures for the "refreshment" in the past, welcoming underground shelters, often carefully finished with precious decorations. The historian Vincenzo Di Giovanni (1550-1627), the ecclesiastic Francesco Baronio Emanfredi (1593-1654), historian Nino Basile (1866-1937)[40]. Important research and cataloguing work was carried out, finally, by the geologist Pietro Todaro[41], who for decades has been conducting a tireless investigation. Today more than thirty examples of these forerunner cooling systems are known some are nowadays ruins, others unreachable, others well maintained or recovered; all datable between the XVII XVIII centuries except for the one in the villa Ambleri-Naselli [42], made in 1552 by the knight Giovan Battista Agliata is described for the first time in 1615 by Vincenzo Di John, in his work Palermo Restaurato.

Among this examples we can recall:

The hypogeum of the "Villa of the Four Rooms"[40]

The "Four Chambers" were named after four sumptuous rooms adorned and painted, which constituted the centrepiece of Don Carlo d'Aragona's villa, destined for his erotic pleasures. Their memory still survives in a neighbourhood in the Zisa district, where once existed this magnificent villa, already which fell into ruin in the seventeenth century; adjacent to it, between the Capuchin convent and the Zisa, the garden of the Siccheria, of which it is also preserved in the name of a street in the neighbourhood. The hypogeum of the "Villa of the Four Rooms", in Mezzomonreale, has been described by Nino Basile as a "cave of wonderful beauty". It was embellished with paintings and frescoes of grotesque scenes. The floor was covered with bricks from Valenza and a stone seat was developed along the circular perimeter of the room.

The hypogeum of the "Villa Agnetta"[40]

Villa Agnetta, which testifies to the presence of a room of the sirocco built by nobleman of Pisa Don Francesco Zoppetta.

The Basile accurately describes other rooms of the sirocco including the one of

The hypogeum of the “Villa Saccone of the barons of Grotta Rossa” [40]

Villa Saccone of the barons of Grotta Rossa: "...there is a beautiful staircase of carved stone preceded by two pillars surmounted by a pine cone with an elegantly shaped support, and then you can access to a semi- circular underground chamber. At the bottom there is a spring surrounded by a balustrade supported by white marble columns; around the walled seats, there are two rectangular niches near the entrance where you can still see the joints for the scans." and that of

The hypogeum of the “Villa Savagnone in fund Micciulla” [40][41]

Villa Savagnone in fund Micciulla and in his writings also speaks of a stone inscription found in the sirocco room of Villa Savagnone, in the district of Altarello, is perhaps the most famous both for its historical past and because it is the only example of open-air room. Of the bottom Micciulla, in which it is excavated, we

30 have news dating back to the fifteenth century when, the then owners, gave in concession the land to a Genoese merchant, Gerardo Battaglia, for the extraction of calcarenite.

During the excavation operations, part of the vault collapsed, revealing the presence of a natural cave and a qanat, dating from the early ninth century, powered by the source of the Uscibene, not far away. The excavation was interrupted, and the cave was abandoned or probably used for water collection for irrigation. The property then passed into the hands of the Jesuits who arrived in Palermo in 1549 and the congregation of the Holy Office, between 1600 and 1698, under the tutelage of Cardinal Mongitore, but no one was interested in the abandoned quarry until, in 1715, the barons Micciulla come into possessionof the estate, they built a villa (sold at auction to the Savagnone family in 1894, together with the garden where the sirocco chamber is located) and also buy the usufruct of the waters of the source of Gabriel, transforming the hypogeum in the sirocco room, according to the canons of fashion of the period.

figura 48 The hypogeum of the “Villa Savagnone in fund Micciulla”

Around the twenties of the last century and for more than forty years, are lost the traces of the owners and of the land which in the 1960s was found to belong to the boss Filippo Piraino. After the kidnapping which took place in 1980, at the request of Judge Giovanni Falcone, the property was entrusted in 1999 to AGESCI, which has been actively involved in the recovery and maintenance of the equipment. It has to be taken in account that this place, over the years had been transformed in an open-air repository of all kinds of waste. Today, it has been completely cleaned up, is presented in all its evocative beauty. A fragrant citrus grove and a stone staircase of billiemas, preceded by two pillars lead to a underground level, about 5 meters below which faces the cave and from which two opposite ramps depart dug into the calcarenite and from which you reach the base of the room at about three meters below. The circular plan is spread over an area of about 100 square meters and the perimeter is bordered by a seat carved into the rock. Along the walls of the room there are two gates that mark the passage of the qanat that used to flow through part of the room floor along a canal, now covered and which contributed to the cooling of the hypogeum. In front of the access staircase, at the base of the rocky wall you can see a small basin in which the waters collected by an intake shaft converge which runs underground for about 50 meters, until it reaches the source of the Uscibene. The small pool also contains the waters of a small waterfall coming from the sources of Gabriel that used to came down from above with roar offering together with the coolness, a pleasant sound and scenographic effect, as well as the possibility of getting wet directly at the contact with water collected in the natural basin below.

Some rooms of the sirocco seem to draw inspiration from the nymphaea and from the artificial caves of classical architecture, cleverly camouflaged by gardens of the villas, like fake natural elements.

Among these, it deserves a mention the small room of Villa Spina in the Piana dei Colli, an artificial cave built inside a large park full of plants and trees and gardens that made the estate an agricultural estate and a holiday resort.

The hypogeum of the “Villa Spina”[40]

The original structure of the villa is that of a hunting lodge, built in 1676 by Vincenzo Vanni and transformed into the current configuration by his son, Alessandro Vanni Torre, Prince of San Vincenzo. There were other owners, including the banker Don Giuseppe Velia, who enters in the possession in 1790, the Isgrò, the Spina and, finally, around the thirties of the last century, the Palminteri family that, along with the lords Venice and Messina, are the current owners of the estate. The small artificial cavern located close to the northeast boundary of the property is hidden by lush vegetation that surrounds the artificial mound and covers the vault of the room on the top of which you can admire a small a horseshoe-shaped belvedere made from blocks of calcarenite. The entrance to the room is through two opposing openings, preceded by as many curvilinear access corridors bordered by walls in blocks of calcarenite that, starting from the ground, rise as you get there.

figura 49 The hypogeum of the “Villa Spina”

Getting closer to the room, the course of the paths is intended to deflect the wind warm of south-east while the juxtaposed openings favour the ventilation the environment. The north door captures the fresh air by conveying it inside of the cave where it comes out through the opposite entrance. An air hole on the vault of the southwest corridor facilitates the escape the hot air. There are no traces of waterways in the immediate vicinity of the cave. The chamber was built on a slight depression of the ground, on which large blocks of calcarenite were set to form an elliptical vault in shape, with an axis greater than 3.9 metres and a height at the highest point of 2.5 meters. A seat, also made of calcarenite, develops along a portion of the seat.

It sometimes happens that what today seems to have always fulfilled its function of the sirocco chamber, in the past, had other destinations.

Cave of the “Beati Paoli”[40]

An example of this is the underground cave of the district of the Capo, in which the Blessed Pauls gathered to decide the fate of dishonest nobles who imposed their power on the weakest. The ancient court underground, now restored, presents all the characteristics of a sirocco room, with a circular environment illuminated from above by a ventilation shaft and delimited by stone seats that develop along the perimeter. An underground well also guaranteed the presence of water and to cool of the environment.

There are still many examples of these very special cooling systems which can still be admired today as a testimony to a past, culture and great civilization that has always characterized the city of Palermo. But in this thesis The Scirocco Room of Villa Ambleri-Naselli will be analysed and modelled with CFD.

4.3 Defining the case study

From the middle age, the trend to spending free time outside the city began more common in the Golden Valley surrounding Palermo. So from the XV century a lot of farms were gradually renovated by the aristocracy to became luxury estates, “place of delight” characterized by gardens completed by water machines, green-houses, lakes waterfalls, labyrinths, etc. After the feudalism these villas were divided to many owners and due to their greatness became expensive to be maintained and were slowly dumped, only some of them are still in a good condition, this is the case of Villa Naselli-Ambleri.

figura 50 Villa Naselli-Ambleri

Villa Naselli-Ambleri (from arab ayn billawri meaning “crystalline fount”[1]) is the typical middle-age baglio (a Sicilian fortified farm, a quadrangular disposition of different buildings around a courtyard) placed South- East to Palermo Mountains in a prelevant position over Ambleri village. It belonged to four important Sicilian families who constant expanded and adorned the property. One of the heirs, Gerardo Agliata built underground “some rooms, large and fair; such a knight used to keep those rooms and galleries decorated by silk curtains and many other ornaments”, this is the Scirocco Room. In the XVIII century the Naselli’s achieved the property and the baglio was renovated to its nowadays style.

Scirocco rooms developed in Palermo during the Renaissance are a typical “low passive cooling architectures” that used natural sources to improve indoor thermal conditions.

They usually are an artificial underground structure, built close to a water spring is characterized by pleasure freshness conditions.

Scirocco Rooms are typologically marked by three main elements:

• The stair, made of rubble or stone mansory; • The proper room, round or quadrangular with a stone vault and completed by little opening and stone seats;

• The water well, located typically in the centre.

The underground structure is manly formed by a tunnel, a wind tower and a water stream. The tunnel is divided by the wind tower into two parts, major and minor gallery. Entire the gallery in constituted by calcarenitc stone.

Villa Naselli’s Scirocco Room is unique for its passive cooling power due to its special architectural configuration. It takes birth from the fusion of two works of hydraulic engineering: a middle age water well and a Renaissance addiction. The truncated cone (wind tower) is the pre-existing medieval water well/basin. Then it’s construction and architectural arrangement change, as Gerardo Agliata made the tunnel built the medieval water well lost its original function of water basin.

The following pictures can show plan and sections of whole structure figura 51.

figura 52 Plan and longitudinal section of the Scirocco Room

Next there is a description of the Villa Ambleri-Naselli’s underground structure with some images and notes kept from a scientific research [1].

The entrance (1) is a groin-arched door located at the main court end. A stone stair leads to a quadrangular uncovered room (5x5 m large), 3 m underground into the Entrance shaft. Exotic plants and marble sculptures of fishes adorn the space. The entrance gives access to the galleries : the minor (13) going N-W under the court, the major (3) is 3 m tall, 3 m large and 50 m long and is split into two sections by a round space called Round, or Fountain (4) figura 53.

figura 54 Minor gallery. A. Wall's gallery dug into the calcarenitic limestone bank and vault's stone disposition. B. Entrance of the minor gallery, vault's stone disposition.

That is 6 m diameter and furnished with stone seats. This space is surmounted by an uncovered squat 10 m tall truncated-cone tower culminating with four little windows (cardinal points oriented) and seven tripartite crenellations Errore. L'origine riferimento non è stata trovata.. Such a structure is the above mentioned medieval well, which presently works as a wind tower, giving birth to the extraordinary cooling operating principle. The major gallery is lightened by seven quadrangular openings (6) 90 cm large, in the barrel vault built every 5 m. It terminates into the Large Fountain (7), 8x8.50 m large. There the Ambleri water springs out. Close to this gallery’s end, four masonry seats let people stay pleasantly nest to water. All galleries’ walls show a little holes’ line (8), 5 cm in diameter and 10 cm deep located every 50 cm at 1.70 m from the ground. They were probably realized to provide walls with vault’s centring and later utilized to hang lanterns, flower garlands and silk curtains in order to adorn the bare place [1].

figura 55 Wind Tower. A. Exploded axonometric view of the medieval waterl well (reconstruction). B. Wind Tower (medieval water well), external view.

From the Large Fountain. Water flows into a covered canal (9) (qanat) under the galleries. Then, it enters a settling-tank (10) and arrives into a water den (11) close to an old lavatory (12), or space for water distribution. Finally, water goes outside the property to irrigate other gardens. There Ambleri water flows into a typical canal made of stone and cement within the citrus-grove. The minor gallery (13) is 1.8 m tall, 2.15 m large and 45 m long. It used to be lightened and aired by five openings (14). A sub rectangular space is in the middle of this gallery (15). It was probably a tiny prison as orally transmitted through the Naselli’s members [1].

Differences and similarities between the Villa Naselli -Ambleri Scirocco chamber and other two main examples

Here are underlined some differences between or case study and two other scirocco Rooms. This scheme was done to better understand the specificity of the Scirocco Room of Villa Ambleri – Naselli. As before mentioned, is quite difficult to talk about a Scirocco Room typology. The presence of underground water is not always a constant in this archetype [40].

In the case of the Scirocco Room of Villa Ambleri – Naselli, the tunnel duct is something quite particular. Also the presence of the all chimneys. How much the form influences the comfort? This is an answer to which we would like to answer through CFD. To have had a different function in history, in general, for the Scirocco Room of Villa A-N but also for the others seems something quite common. But how from thing totally different function/shape finally we came to the same result is still a mystery.

One of the most important elements in our case study seems the wind-tower. The wind direction activate the system and ‘capture the mass flow-rate necessary for the comfort’[1]. No one of the other cases shows this element. Of course, there are small chimneys also in the other examples, but in the Scirocco Room of Villa A-N this element seems the key through which we are able to read the system[42].

Here it is shown a brief legend that define the main elements of the three examples.

LEGEND

- UNDERGROUND SYSTEM (m)

- PRESENCE OF WATER SOURCES

- FUNCTION THAT HAD BEFORE BEING RECOGNISED AS A SCIROCCO ROOM

- PEOPLE SEATS

- SCIROCCO DIRECTION

figura 56 Differences and similarities

5. CFD modelling 5.1 Setting simulations and control volume definition

In order to have a wide issue about the functioning of the Scirocco room five set configurations are chosen for five different months:

• (1) August because has the highest outdoor temperature and the lowest ground temperature in hot climate • (2) Februaty because has the lowest outdoor temperature in cold climate • (3) March because has the lowest ground temperature in cold climate • (4) September because has the highest ground temperature and the lowest outdoor temperature in hot climate • (5) November because has the highest outdoor and ground temperatures in cold climate

Every group simulation listed have three different configurations related to the physical arrangement of the Scirocco Room.

• Case A, that has Sorgiva unroofed and water underground • Case B, that has Sorgiva roofed and no water underground • Case C, that has Sorgiva roofed and water underground

AUGUST FEBRUARY MARCH SEPTEMBER NOVEMBER 1A 2A 3A 4A 5A 1B 2B 3B 4B 5B 1C 2C 3C 4C 5C Table 2 Simulation runned

So there will be presented a total amount of 15 simulations Table 2.

The Figure 1 can show longitudinal section of the ANSYS model and highlights all the elements of the system, that compose the control volume of the CFD analysis. The control volume consists in the air mass present in the Scirocco room and in a small part of the sky.

camino_interno

pavimento(sorgente)

Water steram

pavimento(sorgiva)

Figure 1 Longituninal section of ANSYS's model

• Sorgiva and Sorgiva (acqua) are contact side surfaces between air and Sorgiva chamber

• Pareti_tunnel is contact surface between air and wall gallery surface • Passerella-circolare is contact surface between air and Wind Tower floor • Water stream is contact surface between air and water qanat (that can be empty) • T_fori is contact surface between air and wall chimneys • Sorgente and acqua(sorgente) are contact side surfaces between air and Sorgente chamber • Camino_esterno and camino_interno are indoor/outdoor contact side surfaces between air and Wind Tower • Terreno and Terreno1 are contact surfaces between air and ground • Red, Blue and Green surface define boundary of outdoor air mass volume

Some elements listed above can change their physical arrangement and therefore influence the system temperatures:

• Sorgiva bottom surface (in case A and C there is presence of water) • Sorgiva upper surface (the Sorgiva chamber can be opened or closed) • Water stream (is empty in case B) • Red and Blue surfaces (are the surfaces where the wind direction goes left to right and vice versa, depends on the data coming from the outdoor conditions)

5.2 Setting Data

The main climate data such as Dry Bulb Temperature, Ground Temperature, Wind Direction, Wind Speed and Relative Humidity are derived from Climate Consultant (weather data software). Dry Bulb Temperature, Wind direction, Wind speed and Relative Humidity are kept as monthly average.

Figure 2 Monthly average weather data [Climate Consultant]

For the ground temperature it was be considered its underground distribution.

Figure 3 Ground temperature distribution, [Climate Consultant]

The surface temperatures settled in the ANSYS model are calculated with the formula of Air-Sun temperature [2] reported as follow.

Tas = Tout + αI/h where Tout is the outdoor temperature [3] used for the outdoor surfaces, α is the material diffusivity [2], h = 23 W/m2K is the outdoor heat transfer coefficient [2] and I [W/m2] is the irradiance [4]. It is used direct radiation for horizontal and vertical surfaces directly hit by the sun, while diffuse radiation for those surfaces not facing the sun.

I (W/m2) Coming from PVGis (online software) 275.2264 Direct radiation vertical shape 538.3396 Direct radiation horizontal shape 117.36 Diffuse radiation horizontal shape 73.58 Diffuse radiation vertical shape Table 3 Direct and Diffuce radiantion for vertical and horizontal surfaces, August month, [PVGis]

The input velocity for the ANSYS model is calculate with a formula [2] that take into account terrain characteristic, the wind direction and height where it is evaluated.

α Vz = +/- Vavg*cos(δ + β)*Ks*Z

Where:

β is the wind direction [3] and δ is the angle between North and Scirocco longitudinal axis

Z = 2m, Ks = 0.52 and α = 0.2 are coefficient that depends on the type of ground, Suburbs City with low density

Vavg is the monthly velocity speed average [3]

The following table show the input data settings of ANSYS software related to the first simulation.

2 Tground Ground temperature I (W/m ) Coming from PVGis (online software) Tout (°C) 27 -0.5 (m) -2 (m) -4 (m) 275.2264 Direct radiation vertical shape h (W/m2 K) 23 25 22.5 21 538.3396 Direct radiation horizontal shape Vinlet/Voutlet -0.8

117.36 Diffuse radiation horizontal shape Table 5 Tout, h and v data Table 3 Ground temperature distribution 73.58 Diffuse radiation vertical shape Table 4 Diffuse and Direct radiation

Simulation 1A AUG Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 31.18822783 Tas boundary_t 0 27 Tout vinlet 0 27 Tout terreno 0.92 48.53358491 Tas terreno1 0.92 48.53358491 Tas camino_finestre 0.35 28.78591304 Tas camino_interno 0.35 28.11969565 Tas t_fori 0.35 22.5 Tground at -2m sorgente 0.35 21 Tground at -4m pavimento (sorgente) 0.35 21 Tground at -4m pareti_tunnel 0.35 21 Tground at -4m passerella-circolare 0.35 21 Tground at -4m sorgiva 0.35 21 Tground at -4m wall:022 0.35 21 Tground at -4m Water stream 0.2 16.99999 Tw is water underground temperature Pavimento(sorgiva) 0.2 16.99999 Tw is water underground temperature Table 6 ANSYS data input

For the other simulations the tables are reported in the appendix A.

the three compartments, theradiant temperatures have avery similardistribution inall In theSorgente compartment (left), intheCone Tower (in the centre) andinthetunnels connecting radiated by thesun,andtherefore isstrongly influenced by the radiative effect ofthesun. rence issincetheairflow insidetheSorgiva compartment isin contact with themassof external air closed theradiant andstatic temperatures have ahomogeneous and constant distribution. Thisdiffe va compartment undergo astrong downward variation from top to bottom, whilewhenthesorgiva is It can benoted that intheopen sorgiva configuration the radiant and static temperatures ofthe Sorgi sed sorgiva andyes/no qanat (presence orabsence ofwater inthechannelat thebaseoftunnel). diant andstatic temperatures are also affected bythedifferent configuration of the system: open/clo the ground whichisat lower temperatures thanthemassofoutdoor air. IntheScirocco Room, thera vely), inside theSirocco room thetemperatures are muchlower, thisisdueto theradiative effect of values ofradiant andstatic temperature ofthe external control volume (48°C and37-42°C respecti The August simulations (outdoor air temperature 27°C, ground temperature 25-21°C)show high very CLOSED SORGIVA NO QANAT CLOSED SORGIVA SI QANAT OPEN SORGIVA SI QANAT RADIATION TEMPERATURE AUGUST SIMULATION - 1B 1C 1A - - - - with qanat (25-27°C). ratures insidethe system are slightly lower (23-25°C)compared to theconfiguration ofaspringclosed closed sorgiva andwithout qanat they stop nearthe openings towards theoutside,infact the tempe sorgiva withqanat theisotherms expand throughout thetunnel,whilefor theconfiguration witha This phenomenonisclearly visiblefrom thestatic temperature graphs: inthe configuration ofclosed communicating withthe outside. si qanat, where thepresence ofwater “sucks” thehotaircoming from outsidethrough theopenings lower andhave amore homogeneous distribution thanthe temperatures recorded inthe configuration gurations withclosedsorgiva yes/no qanat: inthe configuration noqanat the static temperatures are A slight difference is recorded instead by analyzing thegraphs of the static temperatures ofthe confi water doesnotsignificantly affect the temperatures recorded intheScirocco Room. a closedspringcompartment makes usunderstand that theradiative effect due tothe presence of three configurations, moreover, the absence ofsubstantial differences between the configurations with AUGUST SIMULATION STATIC TEMPERATURE 1B 1C 1A - - FEBRUARY SIMULATIONS FEBRUARY SIMULATIONS RADIATION TEMPERATURE STATIC TEMPERATURE SI QANAT SORGIVA SORGIVA OPEN 2A 2A SI QANAT SORGIVA SORGIVA CLOSED 2C 2C NO QANAT SORGIVA SORGIVA

CLOSED 2B 2B

The February simulations (outdoor temperature 11°C, ground temperature 12.5-17.5°C) record radiant temperature values inside the tunnel compared to the temperatures recorded with the open sorgiva, temperature values of about 21°C in the external volume of the Scirocco Room , while inside it is kept this is due to the fact that the average temperature of the ground is higher than that of the outside air slightly below, in particular it varies from 18°C to 20°C for the three configurations. In this case, howe- in February. ver, there is no substantial difference between the three configurations: the three systems have very The effect of the presence of water can be seen by analysing the two configurations of closed sorgiva: similar radiant temperature values. the absence of water makes the tunnel more isolated than outside, in fact the static temperatures are From the analysis of the static temperature graphs, which vary from 16°C to 19°C, some slight differen- constant around 19°C (green area) with small areas at a lower temperature 16°C (blue area), while in ces can be seen between the three configurations, in particular: starting from the open sorgiva con- the configuration of closed sorgiva the areas at a lower temperature (16°C) are wide and spread throu- figuration with the presence of qanat the temperatures recorded are slightly lower than those of the ghout the tunnel. closed sorgiva configuration, therefore, as for the August simulations, the closure of the sorgiva has a The presence of water in some way creates convective flows that drag the air outside the tunnel inside mitigating effect with respect to the external temperature conditions. In August the closed sorgiva- ke it, significantly influencing its temperature. eps the temperatures inside the tunnel lower than the temperatures recorded with the open sorgiva; Therefore the configuration with closed sorgiva and absence of water in the qanat makes the system in the month of February the phenomenon is similar but opposite, the closed sorgiva keeps higher Scirocco room more isolated than the external environment. MARCH SIMULATIONS MARCH SIMULATIONS RADIATION TEMPERATURE STATIC TEMPERATURE SI QANAT SORGIVA SORGIVA OPEN 3A 3A SI QANAT SORGIVA SORGIVA CLOSED 3C 3C NO QANAT SORGIVA SORGIVA

CLOSED 3B 3B

The March simulations have very similar outdoor and ground temperatures (outdoor temperature bringing the temperature values closed to the comfort interval. 13°C, ground temperature 12.5-15°C). It can be seen, as for the other previous ones, that the external In these simulations it should be noted that the influence of water, which had marked the previous radiant temperature is higher than the internal one, radiant and static temperatures are almost the simulations, is almost none; in the configurations that differ in the presence of water in the qanat static same inside the tunnel (16-17°C), except for the Sorgente, Sorgiva and Cone Tower compartments. As temperatures, that radiant ones, have very similar distribution so as not to report obvious differences with the August simulations, the radiant temperatures distribution in the surroundings of the Sorgiva in terms of temperature variation. changes considerably if one changes from an open to a closed sorgiva configuration. What significantly influences the results of the system are: the configuration of the sorgiva that modi- The static temperature of the control volume of the external air mass is lower than the static tempera- fies the temperatures recorded in its surroundings, when it is open increases the radiant temperature ture inside the tunnel, contrary to what happens in other simulations. and decreases the static temperature compared to when it is closed; the second is that the radiative Inside the tunnel the static temperature is higher than the radiant temperature because in the simula- effect of the ground increases the temperature inside the Scirocco Room compared to the outside air tions made in March (where the temperature of the outside air is lower than that of the ground, con- temperature towards values closer to the comfort range. trary to what happens in August where the temperature of the ground is lower than the temperature of the outside air) the radiative effect of the ground “increases” the temperature inside the tunnel SEPTEMBER SIMULATIONS SEPTEMBER SIMULATIONS RADIATION TEMPERATURE STATIC TEMPERATURE SI QANAT SORGIVA SORGIVA OPEN 4A 4A SI QANAT SORGIVA SORGIVA CLOSED 4C 4C NO QANAT SORGIVA SORGIVA

CLOSED 4B 4B

The September simulations are very similar to those carried out in August, even if the outside tempe- (about 25°C). The radiant temperature of the outside air is higher than the static temperature becau- rature (24°C) is not higher than that of the ground (23-26°C), sometimes lower, the radiant temperatu- se of radiation. As with the other simulations presented above, the configuration of the sorgiva signi- re of the outside air volume (37-38°C) is usually higher than the radiant temperature inside the tunnel ficantly influences the distribution of temperatures within it: when it is open it quickly decreases from (26-25°C), for the two closed sorgiva configurations the same compartment is at constant distribution top to bottom (37-25°C), when it is closed the temperature in the Sorgiva is almost constant (25°C). temperature (25°C) while for the open sorgiva configuration inside it the radiant temperature gradual- The presence of water also influences the results of the system, this is more visible by analyzing the ly decreases from top to bottom, even if the outside temperature (24°C) is not higher than the ground graphs of the static temperature. In the configuration of a closed sorgiva with qanat the temperature one(23-26°C); the sorgente compartment, the Cone Tower and the tunnels connecting the three com- flow lines develop up to the base of the tunnel where the water is present and the temperature is partments record similar temperatures for all three configurations. 17°C, while in the configuration of a closed sorgiva without qanat they develop mainly in the upper The static temperature measures lower values than the radiant one in the volume representing the part of the tunnel and the temperatures reached are never lower than 23°C. external air (31-35°C), while we have very similar values between radiant and static temperatures in the volume inside the Scirocco Room where the static and radiant temperatures are almost the same NOVEMBER SIMULATIONS NOVEMBER SIMULATIONS RADIATION TEMPERATURE STATIC TEMPERATURE SI QANAT SORGIVA SORGIVA OPEN 5A 5A SI QANAT SORGIVA SORGIVA CLOSED 5C 5C NO QANAT SORGIVA SORGIVA

CLOSED 5B 5B

From the November simulations (outdoor air temperature 17°C, ground temperature 22.5°C) it can be Analyzing the graphs of the static temperature it is clearly visible the influence of the configuration of seen, as for the simulations carried out in March, that the outdoor radiant temperature is higher than the sorgiva on the distribution of its temperature, but it is also clear that the presence of water slightly the indoor one (27°C against about 23°C, here the difference is smaller because the radiance is lower influences the temperatures along the whole tunnel: the static temperatures of the configuration with than in March) and that the indoor static temperatures are slightly higher than the outdoor static closed sorgiva and presence of water in the qanat are slightly lower, characterized in fact by a colour temperatures. Again, the distribution of temperatures near the Sorgiva is strongly influenced by its more tending to blue than green compared to the static termperature of the configuration with closed configuration, while the temperatures in the rest of the Scirocco Room are influenced by the presence sorgiva and absence of water in the qanat. This shows once again how the closed sorgiva configuration of water, both phenomena are more visible from the analysis of the static temperature. and absence of water in the qanat makes the Scirocco Room system more isolated than the external From the analysis of the radiant temperatures comes mainly the relevance of the radiative effect of environment, and therefore less conditioned by the external environmental conditions especially du- the sun and the soil, which in this case are collaborating; the higher temperature of the soil increases ring cold months. the lower temperature of the outside air. 6.2 Best Configuration and best Month

To understand better the functioning of the system is better to split the analysis into two parts:

• Scirocco Room Summer Case (HOT) (August and September simulations) • Scirocco Room Winter Case (COLD) (February, March and November simulations)

For the first case in this section is considered only the August simulation because it has more relevant results. While for the second case are chosen February and November due their opposite wind direction.

To choose the best configuration we start going deep into the analysis of the August simulation, which is the month when usually people used to stay inside the Scirocco Room.

Analysing three configurations from the graphs of static temperature plotted at height of 1.6 m along all the system underground, it can be seen two mainly different behaviours.

Figure 4 August. Static temperature plotted at 1.6 m height along the system

In Case A the Wind Tower temperature at h 1.6 m height is almost <20°C as Case B the Wind Tower temperature at h 1.6 m height is almost >20°C. While in Case C the Wind Tower temperature at h 1.6 m height is higher, almost 30°C.

Case B and case C are very similar; the right part (from x>47m) is the only different curve, the reason is because in that part there is the Sorgiva of the system, so in the case of open sorgiva si qanat, is going to be there water at the base of the sorgiva and the temperature is lower.

In Case A the Sorgiva temperature at h 1.6 m height is almost 18°C.

In Case B the Sorgiva temperature at h 1.6 m height is almost 21°C.

To understand better the differences between the three cases it has been plot a graph (Position(m)/Static Temperature(°C)) of the Wind Tower placed at x = 33m of the system.

Figure 5 August. Static temperature plotted into the centre of the Wind Tower

The worst configurations from this graph is again the one with closed sorgiva si qanat (Case C). The people that are going to lay inside the room will perceive a temperature of almost T=30°C, while in other two cases the difference of temperature felt is about DeltaT=10°C. These results can be explained thanks to the temperature difference between outdoor temperature and indoor temperature:

• In Case A Tout – Tin = 7°C • In Case B Tout – Tin = 6°C • In Case C t Tout -Tin = 0°C (the worst configuration ever)

Again the last configuration shows a completely different behaviour and its lack of performance is due to the fact that the temperature felt outside is more or less the same of the indoor temperature.

At this point the best configurations seems to be the one that has open sorgiva and si qanat better that the closed one with no qanat probably because the presence of water at the base of Scirocco Room cool down the temperature of the air mass flow thanks to the phenomena of evaporative cooling, the water (at lower temperature 17°C) absorbs a relatively large amount of heat from cold air (at 20°C) in order to evaporate, this cool down the air mass .

The reason that underline Case C as worst configuration can be related to some convective flows coming from outside, in this case the qanat become rival of the system sucking hot air from outside increasing the inside temperature, this can be seen from the temperature stratification of the graph below, the flux lines spread until the bottom of the Scirocco room.

Figure 6 August. Static temperature plotted for a longitunal plane section for Case C

February simulation belong to winter case, where the outdoor conditions are completely different from the summer case, the outdoor temperature (11°C) is lower that the underground temperature (15°C) and this leads to a completely different behaviour of the system.

Analysing the static temperature graph along all the Scirocco Room it can be seen a different situation between August and February:

Figure 7 August. Static temperature plotted at 1.6 m height along the system

Figure 8 February. Static temperature plotted at 1.6 m height along the system

While in August black and green line have the same trend (Case A and Case B) instead of the red one (Case C), in February the Case A goes alone.

Figure 9 February. Static temperature plotted into the centre of the Wind Tower

From the graph of the static temperature inside the Wind Tower the worst configuration is the one with open sorgiva si qanat, even if the temperature difference between three configurations is very low.

Probably this is because to keep comfort in the system during cold period it’s better to avoid any kind of flowing air coming from outside, so to do this the sorgiva must be closed.

For what concern the qanat in this case it’s better not to have it because the inside temperature drop down, even if the difference is minimal.

Another element that keeps the Scirocco Room quite isolated during February is the wind direction, in this case the wind blows N-E direction perpendicularly to the axis of the Scirocco Room.

Wind direction

This situation doesn’t occur in the case of November where the wind direction is the same of the gallery direction (N-W exactly opposite to the Scirocco).

Wind direction

For this reason, in November the comfort temperature inside the system seems difficult to be reached but it’s not like this. Even if the sorgiva is closed an important amount of cold air from outside will penetrate the chamber, but the system positively reacts to this condition thanks the heat capacity of the underground. In fact, in November the ground temperature is almost 22.5°C against the outdoor temperature that is around 17°C.

Figure 10 November. Static temperature plotted at 1.6 m height along the system

Figure 11 November. Static temperature plotted into the centre of the Wind Tower

As in the previous case the configurations of closed sorgiva are the best one because keep the system isolated from the external conditions, but here the comfort is better (the temperatures reach are around 20°C against February where the temperatures reach are around 17°C) thanks to the wide power of thermal mass of the calcarenitic stone of the underground (λ 0.7 W/mK).

Thanks to the upper graph (static temperature/position along the system) the function of the small chimneys is underlined, the lower peaks of the curves prove that the colder air from outside goes in through themselves.

6.3 PMV e PPD

Environmental comfort is defined as that condition of comfort determined, according to the sensory perceptions of an individual that is in an environment, by temperature, air humidity and level of noise and brightness detected within the environment. This definition distinguishes between thermo-hygrometric, acoustic and luminous comfort.

Environmental comfort is identified with the psychophysical comfort of the people who live in an environment (home, office) and is a feeling dependent on certain environmental conditions that are largely plannable and therefore fall under the responsibility of the designer, for example in the design, construction and management of a green building.

Thermohygrometric comfort in a building is achieved according to the relationships established between subjective and environmental variables.

The subjective variables are related to the activity that the individual carries out within the environment and the type of clothing.

The environmental variables are those that depend on the climatic conditions outside and inside the building and that influence the thermohygrometric comfort:

• Air temperature • Relative humidity • Radiant temperature • Air velocity

These are indexes of comfort levels that arise from the relationship between the functioning of the human body and the feeling of thermal well-being. The UNI EN ISO 7730 standard identifies two of them:

• The Predicted Mean Vote PMV is an index of evaluation of the state of well-being of an individual and takes into account the subjective and environmental variables; it is therefore a mathematical function that results in a numerical value on a scale with range -3 (index of feeling too cold) to +3 (index of feeling too hot), where the zero represents the state of thermal well-being. Being an average index referred to a group of individuals, the achievement of PMV equal to zero does not mean that the entire group has reached the conditions of well-being. • The Percentage of Person Dissatisfied PPD expresses the percentage of dissatisfied people in each environment.

The following graph represent the PMV/PPD evaluation in the Wind Tower for the main months selected above. The input parameters that act in the index calculation are evaluated as follow:

• Clothing coefficient from a table [5]; • Air temperature coming from ANSYS analysis, it is kept the static temperature at 1.6 m height in the Wind Tower; • Mean radiant temperature coming from ANSYS software in the Wind Tower at 1.6m height; • Activity coefficient from a common table coming from website (users were stationary); • Air speed coming from ANSYS software in the Wind Tower at 1.6m height; • Inside relative humidity calculated as difference between outside relative humidity (coming from Climate Consultant) and humidity rate difference provided by the following graph.

The plot in the following picture is the humidity rate difference (outside/inside) and tendency that is used to calculate the indoor relative humidity.

Figure 12 Humidity rate difference (outside/inside) and tendency, campaign measurement coming from Analytical studies of the Scirocco Room of Villa Naselli-Ambleri done by Manfredi and Enrico Saeli [1]

Regarding the clothing coefficient, are used the following tables [5].

For summer case it is used light clothing while in winter the coefficient is higher.

Figure 13 Clothing coefficient for daily and work wear [5]

For activity met (metabolic equivalent of task) coefficient is used the following common table coming from the website. People used to be stationary and it is chosen light activity level.

Figure 14 Activity MET, methabolic equivalent of task

Parameter Input Clothing (clo) 0.50 Air temp. (°C) 20.0 Mean radiant temp. (°C) 26.0 Activity (met) 1.5 Air speed (m/s) 0.0210 Relative humidity (%) 63.0

Parameter Results Operative temp. (°C) 23 PMV 0.0 PPD 5.0

Figure 15 August. PMV/PPD input and output data and curve

The green part of the curve represents the comfort zone while the left and right parts mean feeling too cold or hot respectively. As it can be seen in August there is a comfort situation.

Parameter Input Clothing (clo) 1.20 Air temp. (°C) 17.5 Mean radiant temp. (°C) 18.0 Activity (met) 1.5 Air speed (m/s) 0.080 Relative humidity (%) 64.0

Parameter Results Operative temp. (°C) 17.75 PMV 0.1 PPD 5.2

Figure 16 February. PMV/PPD input and output data and curve

In February the comfort index is in the green part of the curve. It indicates an index of good felling.

Parameter Input Clothing (clo) 1.20 Air temp. (°C) 19.5 Mean radiant temp. (°C) 23.0 Activity (met) 1.5 Air speed (m/s) 0.001 Relative humidity (%) 63.0

Parameter Results Operative temp. (°C) 21.25 PMV 0.6 PPD 12.5

Figure 17 November. PMV/PPD input and output data and curve

At last in November the comfort index goes slightly on the right of comfort zone that means slightly warm feeling sensation with 12.5 % of people dissatisfied.

So, from these graphs the best month, where the system works better, seems to be November in which the outdoor temperature is 17°C and the ground one is 22.5°C. The huge heat capacity of the ground leads to a comfort conditions inside the Scirocco Room.

7. Conclusions

With between 30% and 40% of the EU’s annual energy consumption caused by the building sector, we appreciate that the target laid down in the Energy Performance of Buildings Directive (EPBD) to install a “Nearly Zero Energy Building” is a must for the coming years. Although this type of building is not yet completely defined, we can be sure that the first priority is to reduce energy demand, whilst the second is to increase renewable energy in buildings. However, the basic objective of a building is not to save energy, but rather to provide the right balance between heating and cooling, to provide good indoor air quality, and to achieve these objectives at acceptable standards and in an efficient manner to proved high user productivity [43].

There are three key objectives in choosing natural ventilation strategies:

• Internal Air Quality (IAQ)

• Thermal comfort

• Energy use reduction

In looking at pre-industrial vernacular we can understand how buildings worked without the use of a low cost, carbon-rich fuel source such as coal or oil; the resultant economy of means provides us with a rich vocabulary of building methods from which to learn. We can see in vernacular architecture a relationship between the building, the microclimate and thermal comfort and understand that vernacular buildings were passive modifiers of the environment[44].

The Scirocco Room was the perfect example to be analysed from this point of view. But how to analyse natural ventilation? How to give scientific results and performance related to the best configurations and other changes? CFD gave us the answer.

Softwares used to analyse ancient and new buildings are CFD or BES tools. Computational fluids dynamics (CFD) is a branch of fluid mechanics that uses numerical analysis and data structures to analyse and solve problems that involve fluid flows. While, building energy simulation (BES) is used for analysis of energy performance of buildings and the thermal comfort of the occupants.

BES programs provide a detailed whole year energy analysis of the target thermal performance building without consideration of the surroundings. However, the relationship between building performance and the surrounding environment is closely connected. Therefore, the lack of interactions with the environment will lead to inaccurate building energy estimation.

CFD technology can provide detailed information of the outdoor environment such as the distribution of wind velocity, air temperature. Since CFD can provide more specific microclimate parameters, a more accurate heat transfer process can be expected and applied in the energy simulation of target building.

Thus, coupling BES with CFB is very attractive, as it poses high potential of accurate analysis of building energy; BES can provide surface temperatures as the boundary conditions for CFD, while CFD can calculates the heat transfer coefficient as input to BES in each time step.

BES programs assume that indoor air is well mixed, and thus cannot accurately predict energy consumption for buildings with non-uniform air temperature distribution in an indoor space, such as those with displacement ventilation systems. For this reason, for the case study analysed it has been chosen a CFD modelling simulation. Furthermore, CFD tools can provide more accurate geometric models. 66

Scirocco Rooms have a very uncommon shape that was hard to be modelled with BES programs. Generally, regarding historical buildings, modelling matter, even before the simulation step, is a major hindrance.

Moreover, CFD simulations have some limits. They don’t include some features:

• Weather data: these data must be taken from other software like Climate Consultant, since Scirocco room is underground system the thermal capacity and the ground temperature play a fundamental role in keeping the comfort into the structure; • Material set data is not accurate: in CFD programs the control volume consists of air, so the surfaces describe dynamic features of the elements; • Problems related to the indoor energy components of the system (internal gains), internal gains can really affect the simulations result; • The model size: to make an accurate analysis is needed a big model with a lot a cell so it’s needed a lot time for simulating and very performance hardware, however it’s better to use a big model especially for the outdoor environment to provide a as much real as turbulence behaviour of the air flow; • Difficult simultaneously generation of geometry and grid that works for both outdoor and indoor environment.

Thanks to CFD it was possible to understand the real functioning of the system and to understand what role is played by each part of the system. With the BES simulation would have been quite impossible to come out with a clear solution of the best configuration.

Because of the acknowledge of the system the simulations were set in this way. Since the Wind Tower is the element that characterized the Scirocco Room of Villa Naselli-Ambleri, the simulations are grouped in terms of outdoor conditions:

• Summer Case (August and September simulations) • Winter Case (February, March and November simulations)

Both the cases are divided then in three parts, these parts depend not anymore on outdoor conditions but on the set up of the system:

• Case A (Sorgiva compartment with no roof and presence of water in the canal) • Case B (Sorgiva compartment with roof and absence of water in the canal) • Case C (Sorgiva compartment with roof and presence of water in the canal)

It wasn’t considered Case D in which the Sorgiva compartment is open and there is not water in the canal because practically is easier to add or to remove the underground river then to create and remove again a roof in the last part of the system.

From the result of the analysis there are four elements that play as main character in the indoor conditions. These are the sorgiva configuration, the ground temperature, wind direction and the presence of water underground.

The Sorgiva must be kept open during the summer period while closed in the winter one because in summer the system is refreshed while in winter it’s better to avoid any air flow at lower temperature coming from outside to inside.

The ground temperature plays a fundamental role thanks to its thermal capacity. During summer period, the ground temperature is lower than the outdoor one so the cold air inside the Scirocco Room is kept insulated from the hotter outside. While in the winter the higher temperature of the ground produce comfort inside the system against bitter temperature outside. 67

The wind direction effects the system in three ways. During the summer case the wind blows parallel to the system from the Sorgiva to the Wind Tower; since the Sorgiva is going to be open the mass flow air blows inside the system and is cooled down by the water that is at lower temperature. In February the wind direction is perpendicular to the main axe of system, so the wind doesn’t blow through the tunnel and the internal conditions wins over the external. While in November and March, even if the wind blows parallel to the system, the main charter that keeps comfort conditions is the ground temperature.

The presence of water underground acts as secondary effect. Its importance is revealed during the summer case with open Sorgiva. In this case the water, through the evaporative cooling, cools down the air coming from outside. But if Sorgiva is closed the canal will act as antagonist for the final comfort inside the Wind Tower. The result will be the stagnation of the air inside the system as also other paper reported.

▪ Appendix

AUGUST SIMULATIONS

2 Tground Ground temperature I (W/m ) Coming from PVGis (online software) Tout (°C) 27 2 -0.5 (m) -2 (m) -4 (m) 275.2264 Direct radiation vertical shape h (W/m K) 23 25 22.5 21 538.3396 Direct radiation horizontal shape Vinlet/Voutlet -0.8

117.36 Diffuse radiation horizontal shape 73.58 Diffuse radiation vertical shape

Simulation 1C AUG Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 31.2 boundary_t 0 27 vinlet 0 27 terreno 0.92 48.5 terreno1 0.92 48.5 camino_finestre 0.35 28.8 camino_interno 0.35 28.2 t_fori 0.35 22.5 sorgente 0.35 21 pavimento (sorgente) 0.35 21 pareti_tunnel 0.35 21 passerella-circolare 0.35 21 sorgiva 0.35 21 wall:022 0.35 21 Water stream 0.2 17 Pavimento(sorgiva) 0.2 17

Simulation 1B AUG Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 31.2 boundary_t 0 27 vinlet 0 27 terreno 0.92 48.5 terreno1 0.92 48.5 camino_finestre 0.35 28.8 camino_interno 0.35 28.2 t_fori 0.35 22.5 sorgente 0.35 21 pavimento (sorgente) 0.35 21 pareti_tunnel 0.35 21 passerella-circolare 0.35 21 sorgiva 0.2 21 wall:022 0.2 21 Water stream 0.2 21 Pavimento(sorgiva) 0.2 21 69

FEBRUARY SIMULATIONS

2 Tg Ground temperature (coming I (W/m ) Coming from PVGis (online software) Tout (°C) 11 from Climate Consultant) 166.293 Direct radiation vertical shape h (W/m2 K) 23 -0.5 (m) -2 (m) -4 (m) 288.439 Direct radiation horizontal shape Vinlet/Voutlet -0.08 12.5 15 17.5 125.9 Diffuse radiation horizontal shape

70.22 Diffuse radiation vertical shape

Simulation 2A FEB Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 13.5 boundary_t 0 11 vinlet 0 11 terreno 0.92 22.5 terreno1 0.92 22.5 camino_finestre 0.35 12.9 camino_interno 0.35 12 t_fori 0.35 15 sorgente 0.35 17.5 pavimento (sorgente) 0.35 17.5 pareti_tunnel 0.35 17.5 passerella-circolare 0.35 17.5 sorgiva 0.35 17.5 wall:022 0.35 17.5 Water stream 0.2 17 Pavimento(sorgiva) 0.2 17

Simulation 2C FEB Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 13.5 boundary_t 0 11 vinlet 0 11 terreno 0.92 22.5 terreno1 0.92 22.5 camino_finestre 0.35 12.9 camino_interno 0.35 12 t_fori 0.35 15 sorgente 0.35 17.5 pavimento (sorgente) 0.35 17.5 pareti_tunnel 0.35 17.5 passerella-circolare 0.35 17.5 sorgiva 0.35 17.5 wall:022 0.35 17.5 Water stream 0.2 17 Pavimento(sorgiva) 0.2 17

Simulation 2B FEB Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 13.5 boundary_t 0 11 vinlet 0 11 terreno 0.92 22.5 terreno1 0.92 22.5 camino_finestre 0.35 12.9 camino_interno 0.35 12 t_fori 0.35 15 sorgente 0.35 17.5 pavimento (sorgente) 0.35 17.5 pareti_tunnel 0.35 17.5 passerella-circolare 0.35 17.5 sorgiva 0.35 17.5 wall:022 0.35 17.5 Water stream 0.35 17.5 Pavimento(sorgiva) 0.35 17.5

MARCH SIMULATIONS

2 Tg Ground temperature (coming I (W/m ) Coming from PVGis (online software) Tout (°C) 13 from Climate Consultant) 229.13 Direct radiation vertical shape h (W/m2 K) 23 -0.5 (m) -2 (m) -4 (m) 400.74 Direct radiation horizontal shape Vinlet/Voutlet 1.7 12.5 14 15 165.98 Diffuse radiation horizontal shape 97.08 Diffuse radiation vertical shape

Simulation 3A MAR Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 16.5 boundary_t 0 13 vinlet 0 13 terreno 0.92 29 terreno1 0.92 29 camino_finestre 0.35 15.5 camino_interno 0.35 14.5 t_fori 0.35 14 sorgente 0.35 15 pavimento (sorgente) 0.35 15 pareti_tunnel 0.35 15 passerella-circolare 0.35 15 sorgiva 0.35 15 wall:022 0.35 15 Water stream 0.35 17 Pavimento(sorgiva) 0.35 17

Simulation 3C MAR Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 16.5 boundary_t 0 13 vinlet 0 13 terreno 0.92 29 terreno1 0.92 29 camino_finestre 0.35 15.5 camino_interno 0.35 14.5 t_fori 0.35 14 sorgente 0.35 15 pavimento (sorgente) 0.35 15 pareti_tunnel 0.35 15 passerella-circolare 0.35 15 sorgiva 0.35 15 wall:022 0.35 15 Water stream 0.35 17 Pavimento(sorgiva) 0.35 17

Simulation 3B MAR Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 16.5 boundary_t 0 13 vinlet 0 13 terreno 0.92 29 terreno1 0.92 29 camino_finestre 0.35 15.5 camino_interno 0.35 14.5 t_fori 0.35 14 sorgente 0.35 15 pavimento (sorgente) 0.35 15 pareti_tunnel 0.35 15 passerella-circolare 0.35 15 sorgiva 0.35 15 wall:022 0.35 15 Water stream 0.35 15 Pavimento(sorgiva) 0.35 15

SEPTEMBER SIMULATIONS

2 Tg Ground temperature (coming I (W/m ) Coming from PVGis (online software) Tout (°C) 24 from Climate Consultant) 220.47 Direct radiation vertical shape h (W/m2 K) 23 -0.5 (m) -2 (m) -4 (m) 416.82 Direct radiation horizontal shape Vinlet/Voutlet -1.2 26 24 22.5 137.69 Diffuse radiation horizontal shape 79.73 Diffuse radiation vertical shape

Simulation 4A SEPT Open sorgiva si qanat Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 27.4 boundary_t 0 24 vinlet 0 24 terreno 0.92 40.7 terreno1 0.92 40.7 camino_finestre 0.35 26.1 camino_interno 0.35 25.2 t_fori 0.35 24 sorgente 0.35 22.5 pavimento (sorgente) 0.35 22.5 pareti_tunnel 0.35 22.5 passerella-circolare 0.35 22.5 sorgiva 0.35 22.5 wall:022 0.35 22.5 Water stream 0.35 17 Pavimento(sorgiva) 0.35 17

Simulation 4C SEPT Closed sorgiva si qanat Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 27.4 boundary_t 0 24 vinlet 0 24 terreno 0.92 40.7 terreno1 0.92 40.7 camino_finestre 0.35 26.1 camino_interno 0.35 25.2 t_fori 0.35 24 sorgente 0.35 22.5 pavimento (sorgente) 0.35 22.5 pareti_tunnel 0.35 22.5 passerella-circolare 0.35 22.5 sorgiva 0.35 22.5 wall:022 0.35 22.5 Water stream 0.35 17 Pavimento(sorgiva) 0.35 17

Simulation 4B SEPT Closed sorgiva no qanat Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 27.4 boundary_t 0 24 vinlet 0 24 terreno 0.92 40.7 terreno1 0.92 40.7 camino_finestre 0.35 26.1 camino_interno 0.35 25.2 t_fori 0.35 24 sorgente 0.35 22.5 pavimento (sorgente) 0.35 22.5 pareti_tunnel 0.35 22.5 passerella-circolare 0.35 22.5 sorgiva 0.35 22.5 wall:022 0.35 22.5 Water stream 0.35 22.5 Pavimento(sorgiva) 0.35 22.5

NOVEMBER SIMULATIONS

2 Tg Ground temperature (coming I (W/m ) Coming from PVGis (online software) Tout (°C) 17 from Climate Consultant) 161.67 Direct radiation vertical shape h (W/m2 K) 23 -0.5 (m) -2 (m) -4 (m) 269.43 Direct radiation horizontal shape Vinlet/Voutlet 1.68 22.5 22.5 22.5 108.82 Diffuse radiation horizontal shape 63.33 Diffuse radiation vertical shape

Simulation 4A NOV Open sorgiva si qanat Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 19.5 boundary_t 0 17 vinlet 0 17 terreno 0.92 27.8 terreno1 0.92 27.8 camino_finestre 0.35 18.7 camino_interno 0.35 18 t_fori 0.35 22.5 sorgente 0.35 22.5 pavimento (sorgente) 0.35 22.5 pareti_tunnel 0.35 22.5 passerella-circolare 0.35 22.5 sorgiva 0.35 22.5 wall:022 0.35 22.5 Water stream 0.35 17 Pavimento(sorgiva) 0.35 17

Simulation 4C NOV Closed sorgiva si qanat Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 19.5 boundary_t 0 17 vinlet 0 17 terreno 0.92 27.8 terreno1 0.92 27.8 camino_finestre 0.35 18.7 camino_interno 0.35 18 t_fori 0.35 22.5 sorgente 0.35 22.5 pavimento (sorgente) 0.35 22.5 pareti_tunnel 0.35 22.5 passerella-circolare 0.35 22.5 sorgiva 0.35 22.5 wall:022 0.35 22.5 Water stream 0.35 17 Pavimento(sorgiva) 0.35 17

Simulation 4B NOV Closed sorgiva no qanat Element name α (diffusivity) ANSYS input temp. (°C) camino_esterno 0.35 19.5 boundary_t 0 17 vinlet 0 17 terreno 0.92 27.8 terreno1 0.92 27.8 camino_finestre 0.35 18.7 camino_interno 0.35 18 t_fori 0.35 22.5 sorgente 0.35 22.5 pavimento (sorgente) 0.35 22.5 pareti_tunnel 0.35 22.5 passerella-circolare 0.35 22.5 sorgiva 0.35 22.5 wall:022 0.35 22.5 Water stream 0.35 22.5 Pavimento(sorgiva) 0.35 22.5

▪ References

[1] M. Saeli and E. Saeli, “Analytical studies of the Sirocco room of Villa Naselli-Ambleri: A XVI century passive cooling structure in Palermo (Sicily),” J. Cult. Herit., vol. 16, no. 3, pp. 344–351, 2015. [2] S. P. Corgnati and M. Perino, “CFD application to optimise the ventilation strategy of Senate Room at Palazzo Madama in Turin (Italy),” J. Cult. Herit., 2013. [3] C. Balocco and G. Grazzini, “Numerical simulation of ancient natural ventilation systems of historical buildings. A case study in Palermo,” J. Cult. Herit., 2009. [4] J. Franke et al., “Recommendations on the use of CFD in wind engineering,” COST Action C14 Impact Wind Storm City Life Urban Environ., pp. 1–11, 2004. [5] B. Blocken, “Computational Fluid Dynamics for urban physics: Importance, scales, possibilities, limitations and ten tips and tricks towards accurate and reliable simulations,” Build. Environ., vol. 91, pp. 219–245, 2015. [6] V. Heijst and V. Hooff, “CFD simulation and validation of urban microclimate : a case study for Bergpolder Zuid , Rotterdam CFD simulation and validation of urban microclimate : A case study for Bergpolder Zuid , Rotterdam,” vol. 83, no. August, pp. 79–90, 2017. [7] D. D’Agostino and P. M. Congedo, “CFD modeling and moisture dynamics implications of ventilation scenarios in historical buildings,” Build. Environ., 2014. [8] J. I. Perén, T. van Hooff, B. C. C. Leite, and B. Blocken, “CFD analysis of cross-ventilation of a generic isolated building with asymmetric opening positions: Impact of roof angle and opening location,” Build. Environ., vol. 85, no. 2015, pp. 263–276, 2015. [9] K. A. Papakonstantinou, C. T. Kiranoudis, and N. C. Markatos, “Computational analysis of thermal comfort: The case of the archaeological museum of Athens,” Appl. Math. Model., 2000. [10] C. Balocco, “Daily natural heat convection in a historical hall,” J. Cult. Herit., 2007. [11] A. S. Hussein and H. El-Shishiny, “Influences of wind flow over heritage sites: A case study of the wind environment over the Giza Plateau in Egypt,” Environ. Model. Softw., 2009. [12] I. Requena-Ruiz, “Thermal comfort in twentieth-century architectural heritage: Two houses of Le Corbusier and André Wogenscky,” Front. Archit. Res., 2016. [13] T. A. G. Smyth and R. Quinn, “The role of computational fluid dynamics in understanding shipwreck site formation processes,” J. Archaeol. Sci., 2014. [14] L. Tang, M. Nikolopoulou, F. Y. Zhao, and N. Zhang, “CFD modeling of the built environment in Chinese historic settlements,” Energy Build., 2012. [15] A. T. Nguyen, Q. B. Tran, D. Q. Tran, and S. Reiter, “An investigation on climate responsive design strategies of vernacular housing in Vietnam,” Build. Environ., 2011. [16] C. Balocco, G. Petrone, and G. Cammarata, “Numerical multi-physical approach for the assessment of coupled heat and moisture transfer combined with people movements in historical buildings,” Build. Simul., vol. 7, no. 3, pp. 289–303, 2014. [17] M. Castro-García, J. I. Rojas-Sola, and E. De La Morena-de La Fuente, “Technical and functional analysis of Albolafia waterwheel (Cordoba, Spain): 3D modeling, computational-fluid dynamics simulation and finite-element analysis,” Energy Convers. Manag., 2015. [18] T. Pujol, J. Solà, L. Montoro, and M. Pelegrí, “Hydraulic performance of an ancient Spanish 76

watermill,” Renew. Energy, 2010. [19] C. R. Ortloff, “Water engineering at Petra (Jordan): Recreating the decision process underlying hydraulic engineering of the Wadi Mataha pipeline system,” J. Archaeol. Sci., 2014. [20] B. Haut and D. Viviers, “Analysis of the water supply system of the city of Apamea, using computational fluid dynamics. Hydraulic system in the north-eastern area of the city, in the Byzantine period,” J. Archaeol. Sci., 2007. [21] G. Tseropoulos, Y. Dimakopoulos, J. Tsamopoulos, and G. Lyberatos, “On the flow characteristics of the conical Minoan pipes used in water supply systems, via computational fluid dynamics simulations,” J. Archaeol. Sci., 2013. [22] G. R. Tabor, D. Molinari, and G. Juleff, “Computational simulation of air flows through a Sri Lankan wind-driven furnace,” J. Archaeol. Sci., 2005. [23] F. Pagliaro, E. Bukowiecki, F. Gugliermetti, and F. Bisegna, “The architecture of warehouses: A multidisciplinary study on thermal performances of Portus’ roman store buildings,” J. Cult. Herit., 2015. [24] C. Balocco, “Analysis of Ancient Natural Ventilation Systems inside the Pitti Palace in Florence,” Energy, 2008. [25] D. Camuffo et al., “An advanced church heating system favourable to artworks: A contribution to European standardisation,” J. Cult. Herit., 2010. [26] P. Pineda and A. Iranzo, “Analysis of sand-loaded air flow erosion in heritage sites by Computational Fluid Dynamics: Method and damage prediction,” J. Cult. Herit., 2017. [27] S. Pitsch, S. Holmberg, and J. Angster, “Ventilation system design for a church pipe organ using numerical simulation and on-site measurement,” Build. Environ., 2010. [28] A. Mikayama, S. Hokoi, D. Ogura, K. Okada, and B. Su, “Effects of drifting sand particles on deterioration of mural paintings on the east wall of cave 285 in Mogao caves, Dunhuang,” in Energy Procedia, 2015. [29] C. Bonacina, P. Baggio, F. Cappelletti, P. Romagnoni, and A. G. Stevan, “The Scrovegni Chapel: The results of over 20 years of indoor climate monitoring,” Energy Build., 2015. [30] F. Ascione and F. Minichiello, “Microclimatic control in the museum environment: Air diffusion performance,” Int. J. Refrig., vol. 33, pp. 806–814, 2010. [31] S. Albero, C. Giavarini, M. L. Santarelli, and A. Vodret, “CFD modeling for the conservation of the Gilded Vault Hall in the Domus Aurea,” J. Cult. Herit., vol. 5, no. 2, pp. 197–203, 2004. [32] F. Stazi, A. Vegliò, C. Di Perna, and P. Munafò, “Experimental comparison between 3 different traditional wall constructions and dynamic simulations to identify optimal thermal insulation strategies,” Energy Build., vol. 60, pp. 429–441, 2013. [33] H.-J. T. 801001854676 001999074717 Steeman, M. Ug. 002002154061 802000189992 Van Belleghem, A. T. 801001330674 0000-0003-4950-4704 Janssens, and M. T. 801001009059 0000- 0003-0233-0719 De Paepe, “Coupled simulation of heat and moisture transport in air and porous materials for the assessment of moisture related damage,” Build. Environ., 2009. [34] C. Pasquarella et al., “A multidisciplinary approach to the study of cultural heritage environments: Experience at the Palatina Library in Parma,” Sci. Total Environ., 2015. [35] G. Litti, A. Audenaert, and J. Braet, “Natural ventilation as passive cooling strategy aimed at summer overheating reduction in heritage buildings: the case study of Vlesshuis museum in Antwerp

(Belgium),” Eur. Conf. Sustain. , Energy Environ. 2014 Off. Conf. Proc., no. March 2015, pp. 277–293, 2014. [36] J. Srebric, V. Vukovic, G. He, and X. Yang, “CFD boundary conditions for contaminant dispersion, heat transfer and airflow simulations around human occupants in indoor environments,” Build. Environ., 2008. [37] W. Oh and S. Kato, “The effect of airspeed and wind direction on human’s thermal conditions and air distribution around the body,” Build. Environ., vol. 141, 2018. [38] J. Grau-Bové, L. Mazzei, M. Strlic, and M. Cassar, “Fluid simulations in heritage science,” Herit. Sci., vol. 7, no. 1, pp. 1–12, 2019. [39] S. H. Hosseini, E. Shokry, A. J. A. Hosseini, G. Ahmadi, and J. K. Calautit, “Evaluation of airflow and thermal comfort in buildings ventilated with wind catchers: Simulation of conditions in Yazd City, Iran,” Energy Sustain. Dev., vol. 35, pp. 7–24, 2016. [40] V. Olgyay, “Le camere dello scirocco : archetipi bioclimatici della Palermo antica.” [41] P. Palermo, “Sistemi d’acqua tradizionali siciliani : qanat, ingruttati e pozzi allaccianti nella Piana di Palermo,” no. November, 2014. [42] M. Saeli, “M AnFREDI S AELI , E nRICO S AELI Luoghi di delizie nella Palermo del XVI secolo . Il caso di villa Naselli-Ambleri,” no. January, 2017. [43] C. Händel, “Is a Necessity in ‘ Nearly Zero ’ Energy Buildings,” Energy, no. May, pp. 18–22, 2011. [44] M. P. G. Haslam and A. Farrell, “NATURAL VENTILATION STRATEGIES IN NEAR- ZERO-ENERGY BUILDING A design primer for students and professionals The purpose of the research is to understand how effectively passive environmental design impacts on architectural form and to test the assumptio,” no. 1984, pp. 619–630, 2014.

[1] E. S. Manfredi Saeli, Analytical studies of the Scirocco Room of Villa Naselli-Ambleri: XVI ventury passive cooling sructure in Palermo, Palermo, 2014.

[2] F. Butera, Architettura e ambiente. Manuale per il controllo della qualità termica, luminosa e acustica degli edifici., ETAS, 1995.

[3] Climate Consultant.

[4] «PVGis,» [Online].

[5] S. Z. M. a. R. Sager, Performance of protective clothing.