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Article

Energetic Performance of Natural Building Materials: Numerical Simulation and Experimental Evaluation

by
Costantino Carlo Mastino
*,
Giovanna Concu
* and
Andrea Frattolillo
Department of Civil and Environmental Engineering and Architecture, University of Cagliari, 09123 Cagliari, Italy
*
Authors to whom correspondence should be addressed.
Energies 2024, 17(4), 768; https://doi.org/10.3390/en17040768
Submission received: 14 November 2023 / Revised: 22 January 2024 / Accepted: 28 January 2024 / Published: 6 February 2024
(This article belongs to the Section G: Energy and Buildings)

Abstract

:
The current goal of the European Commission, which aims to reduce CO2 by 90% compared to values estimated in 1980, and the ever-increasing sensitivity to environmental sustainability, fully involve the construction sector, which, according to the OECD (Organization for Economic Co-Operation and Development) is responsible for over one-third of the world’s energy requirement. In this frame, numerous researchers and companies are focusing on ecologically sustainable building materials, to be used in new and existing buildings, that are able to simultaneously fulfill the constructive function and improve the energy behavior of the building envelope. The goal of the present paper is the analysis of the energy performance of some innovative locally produced natural building materials (timber, sheep wool, rammed earth, lime-based plaster, natural fibers) used in multilayer vertical closures, compared to that of more common building materials (bricks, concrete, synthetic insulation). First, the physical-mechanical characterization of the local natural materials was carried out, then the model of a building was implemented, whose energetic performance was simulated by varying the type of stratigraphy of the walls, including the use of both innovative and common materials. The building chosen for the simulation consists of one of the BESTEST ANSI/ASHRAE reported in the 140-2017 standard using the climatic data of the Mediterranean area. The results of the simulation have been presented and discussed.

1. Introduction

The concept of eco-efficiency in architecture indicates the capacity of a building or urban district to attain the achievement, production and supply objectives of goods and services using less and less resources and creating less and less waste and pollution [1,2,3,4]. For understanding the level of eco-efficiency of a particular ecosystem, it is important to consider the following three factors:
  • the flow of matter, energy and information that is determined in that reality;
  • the interdependence of the organisms that live in that reality;
  • the effectiveness of material and intangible transfers that take place between the various levels of their organization.
According to the WBCSD (World Business Council for Sustainable Development), eco-efficiency can be pursued by providing products and services at competitive prices that meet human needs by increasing the quality of life with less consumption of natural resources and a progressively minor ecological impact. The strategies to achieve eco-efficiency are, on the one hand, to reduce the dispersion of toxic and waste materials in general and, on the other, to increase the recyclability of materials and waste, the use of renewable resources, and the duration of the components.
Some studies have highlighted how the use of sustainable materials is linked to the actual possibility of finding substitute materials to those commonly used [5]. Other studies have also highlighted that the production and use of sustainable materials is linked to cost, performance, and possible subsidies for their production or use [4].
Recent trends in eco-sustainability highlighted that in the construction sector, particularly housing, the use of building materials of natural origin, both vegetable and animal, is increasing, as these materials are seen as cost-effective, energy efficient, and healthy [6]. The use of natural building materials is often linked to the opportunity for local production, and therefore to the possibility of enhancing local production chains and the circular economy, with consequent benefits in terms of environmental, economic, and social sustainability. Natural building materials can be used directly as load-bearing structural materials, as in the case of timber buildings [7,8] and earth brick masonry [9,10], as external reinforcing elements for other load-bearing materials [11,12,13,14,15,16,17], as additives to improve the performance of other materials [18,19,20], and as insulating materials, as in the case of cork [21], sheep wool [22], wood-derived panels [23], earth-derived elements [24], etc. [17].
Despite their specific qualities, and the benefit they can bring in terms of sustainability, natural materials are not widespread in the construction sector, and conventional materials are still predominantly used. That depends on various factors, including the inadequacy of the related standards, the inefficiency of the production chains, and the non-competitive cost, due to the current low demand, the feeling that these materials, being natural, are subject to greater deterioration than conventional ones, and cannot meet the same performance requirements.
In this regard, in 2020 the European Commission launched the Renovation Wave Strategy [25], a program to improve the energy performance of buildings. This strategy assumes that minimizing the footprint of buildings requires resource efficiency and circularity combined with turning parts of the construction sector into a carbon sink, for example, through the promotion of green infrastructure and the use of organic building materials that can store carbon, such as sustainably sourced wood. The main actions of the strategy include the need to expand the market for sustainable construction products and services, also by integrating new materials and nature-based solutions and promoting their use.
This paper fits into this context, presenting the results of research aimed at evaluating the performance of some innovative natural materials of local production used in wall stratigraphy and comparing them with those of conventional materials. First, the determination, experimental or based on the literature, of the main physical-mechanical characteristics of various natural materials of potential interest for the study was carried out, then a building model was implemented, and the numerical simulation of its energy performance was carried out as the stratigraphy of the walls was varied. As part of the simulation, stratigraphies consisting entirely of natural materials, stratigraphies consisting exclusively of conventional materials, and mixed stratigraphies were considered. The building chosen for the simulation consists of one of the BESTEST ANSI/ASHRAE reported in the 140-2017 standard [26,27] using the climatic data of the Mediterranean area.
In general, the simulation highlights that the performance of walls with innovative natural materials layers and that of walls with conventional materials layers does not vary appreciably in terms of the thermal energy required for heating or cooling. This technical aspect adds to the sustainability associated with the use of locally produced natural building materials. Natural building materials use row materials already present in nature and not deriving from industrial processes often very harmful for the environment, thus they contribute to the reduction of Carbon Footprint [28,29,30]. The choice to build with natural materials falls within the interventions aimed at reducing CO2 emissions, enhancing the activities of social and environmental responsibility [31]. In fact, many synthetic materials used in buildings require significant quantities of energy and resources to be produced, which can contribute to Greenhouse Gas emissions [32,33,34]. Natural materials, on the other hand, often come from renewable resources and their production process is generally less energy demanding. During the construction phase these materials also cause less pollution from the construction site [34]. Furthermore, the use of natural materials can help reduce the amount of waste generated during the construction process since they can be recycled, reused, or disposed of more easily than synthetic alternatives [34,35]. The use of natural materials contributes to supporting biodiversity, as they come from sustainable forests and other ecologically sensitive areas, which are the subject of strict environmental compensation actions [34,36]. Obviously, since in some cases these materials may be sensitive to parasites present in nature, in this case it is necessary to apply suitable and effective production and stabilization processes.
The study developed in this work analyzed the use of natural materials taking into account the legislative context in force in the Italian national territory. The Italian legislation, based on the receipt of the various European directives that, starting from 2002/91/EC, have followed [37,38,39], does not provide for most of the works on new or existing assessments an energy–environment balance. Most of the checks are based on the energy, balanced only by following what is reported in the ISO 13790 technical standard [40]. The calculation model created through the use of a BIM platform (Building Information Modeling) [41,42,43,44], based on national legislation, has consequently obtained results based on the energy budget only. These results do not take into account, for example, an analysis of the life cycle (Life Cycle Assessment, LCA) of the materials, an aspect developed by numerous authors for these types of materials [45,46,47], even with the use of BIM [48,49,50,51]. The choice of this evaluation is made as a consequence of the fact that on the national scene, to date, the evaluations on energy transfers do not consider energy–environment efficiency indicators that take into account the energy cost for the production of the materials used. Today in Italy, there is no national procedure that allows you to evaluate the advantages in the use of natural materials and which considers this in the energy classification provided for by national laws. Some local regulations are exceptions, such as the province of Bolzano, which applies the Clima House protocol. The LCA is a very useful tool for evaluating the environmental impact of building materials along the entire life cycle, including production, use, and disposal. The LCA should be carried out as soon as possible in the design process. This is because it allows you to carry out aware and informed assessments regarding which product is actually most suitable for a building for which sustainability is an objective. Furthermore, starting from 2030, the Directive on the Energy Performance of Buildings (EPBD) [39] of the European Union will require the quantification of total emissions (Whole-Life Carbon, WLC) for new buildings, making LCA even more relevant. It is remembered, however, as aforementioned, that the adoption of LCA in construction in Italy is still limited. To perform an analysis of the life cycle (LCA) of a building material, several pieces of data are needed. In particular, data on materials and processes are needed; these data, which can be obtained from databases such as Ecoinvent [52], are necessary to calculate the embodied carbon of materials and processes present in a project. Currently these data are not available for the materials analyzed, since they are not coded for production at an industrial level.

2. Materials and Stratigraphies

2.1. Base Materials

The study involved both innovative locally sourced natural building materials and building materials already available in the market. In detail, the natural locally sourced materials selected for the study are the following:
  • Cross Laminated Timber (CLT) panels of Sardinian Maritime Pine as load-bearing material;
  • Sheep wool and Rammed Earth-based panels, with added natural fibers, as insulating materials;
  • Lime-based plaster, also with added natural fibers, and Sardinian Maritime Pine boards, as finishing.
These materials are sourced locally in the island of Sardinia, Italy, to guarantee an ecological and circular approach to resource management, and have been studied in the framework of a dedicated research project called PLES (Local Products for Sustainable Buildings) [6].
Table 1 shows the main characteristics of the materials involved in the study. Data concerning innovative natural locally sourced materials were obtained either from the PLES experimental activity [53] or from the literature [54,55,56], whereas data concerning materials already commercially available were inferred either from the producer or from experimental tests.

2.2. Stratigraphies

Base materials described in Table 1 have been combined to obtain 20 stratigraphies to be analyzed by numerical simulation, as shown in Figure 1. Table 2 shows the composition of the stratigraphies in terms of materials, layer disposition from outside to inside, and layer thickness.
Figure 1 exhibits the twenty types of walls studied. The types from W01 to W06 represent typical walls used in Sardinia in the buildings where it is possible to intervene to improve the thermal insulation performance with an external and/or internal insulating coating, as shown in the drawings of the aforementioned examples. The types from W09 to W14 and W19 to W20 represent walls with structural wood to be used in new buildings while the types from W07 to W08 and from W15 to W18 represent new walls to be used on new constructions that put together natural materials and traditional materials.
Table 3 shows the main energetic characteristics of the building stratigraphies considered in the simulation model. The performance data of the stratigraphies have been obtained either from calculations according to standards or from the literature [53,63,64]. It is worth noting that the set of stratigraphies considered for the numerical simulation includes stratigraphies consisting of natural materials, chosen among those illustrated in Table 1, stratigraphies consisting of conventional materials, and mixed stratigraphies of natural and conventional materials.
The standards to which reference has been made for the calculation of the parameters in Table 3 are the following:
  • Frontal mass Ms;
  • Thermal transmittance U [65];
  • Periodic thermal transmittance YIE [66];
  • Noise insulation index Rw [67];
  • Vapor permeance Π [61];
  • Internal thermal capacity for square meter k1 [66].

2.3. Numerical Simulation

The energetic performance of the stratigraphies shown in Table 2 has been analyzed and compared with reference to the case study BEST CASE ANSI/ASHARE Standard 140-2017 140 [26], whose characteristics are shown in Figure 2. Figure 2 shows the volume, the surface of the windows, and the size of the building taken as reference for calculations. The ratio between the surface of the windows and the surface of the floor is also reported.
The simulation model used is that provided at the European level, based on the UNI EN ISO 13790 standard [40], adapted to the national climatic type of Italy and validated by the CTI (Italian thermotechnical committee).
The model evaluates the energy needs of the building for winter and summer air conditioning. The requested data are, summarily, the thermo-energy properties of the materials, the stratigraphies, the climatic data, the geometry of the building, and its orientation. For the thermo-energy data of the materials, those of the natural materials investigated experimentally in the laboratories of the University of Cagliari [53,57] and those present in the various technical standards [58,59,60] of reference in the Italian territory have been used.
The numerical simulation consists in calculating the ideal energy needs for both heating and cooling the internal environment as a function of the various wall stratigraphies. The simulation was performed considering a set point temperature of the internal air equal to 20 °C in winter and 26 °C in summer. For the external climate, the data of the National Technical Standard of the UNI 10349 series [68,69,70] were taken as a reference considering the Mediterranean climate of the City of Cagliari in Sardinia, Italy. The simulation was carried out on each of the twenty stratigraphies described in Table 2 and Figure 1. The number of days when the intervention of the plant system is needed to maintain the set point temperature both for cooling (Figure 3) and heating (Figure 4) has been calculated. Finally, the needs of the ideal monthly energy have been calculated for both cooling and heating (Figure 5). The simulation assumes an absorption coefficient of solar thermal radiation, as defined by ISO 13786 [66], equal to 0.3 for light-colored surfaces. In this study, only the ideal energy requested by the internal environments to maintain the thermo-hygrometric conditions of the project has been evaluated, and the use of a plant system for the generation of thermal or cooling energy has not been accounted for.

3. Results and Discussion

The results obtained from the numerical simulation are shown in Figure 3, Figure 4 and Figure 5 in which the days of cooling, days of heating, and monthly energy request for heating and cooling are reported.
Figure 3 clearly shows that the number of days when cooling energy is required is quite similar for the stratigraphies. The stratigraphy that requires the action of cooling systems for a higher number of days is W13, with 131 days/year, while the one that requires it for the lowest number is W08, with 110 days/year.
Figure 4 shows the number of days when it is necessary to heat the room to reach an internal temperature of 20 °C according to Italian national legislation. The W08 stratigraphy requires the action of heating systems for the highest number of days, 174 days/year, while the W13 stratigraphy requires it for the lowest number of days, 167 days/year.
Figure 5 shows the monthly request for energy. It can be noted that stratigraphy W08 needs Qc = 676 kWh/year for an ideal energy request for cooling during the summer and Qh = 1600 kWh/year for heating during the winter, while stratigraphy W13 needs Qc = 676 kWh/year for an ideal energy request for cooling during the summer and Qh = 1600 kWh/year for heating during the winter. Thus, stratigraphy W08 is better performing than W13 in the cooling period, while stratigraphy W13 is better performing than W08 during the heating period.
The results obtained from the numerical simulations clearly highlight the role played by the mass of the structures in minimizing or maximizing the energy request for heating and cooling, as shown by walls W08 and W13. Figure 3 shows that in May (cooling period) W08 requires only four days of air conditioning to reach the set point temperature, while in the same period W13 requires thirteen days of air conditioning. Figure 4 shows that in October (heating period) the situation is reversed, as W08 requires two days of heating system intervention while W13 requires zero days. This behavior is specific to considered stratigraphy according to the distribution of the mass of the insulation layer. At the same time, an important role in finding a solution that balances the envelope performance in the periods of heating and cooling is played by the position of the insulating layer, or layers, within the stratigraphy. A stratigraphy that balances the two aspects well is W04, which has insulating layers both on the external and internal side of the wall.
In summary, the use of natural building materials can bring numerous benefits for the well-being of the occupants, the environment, and the local economy. By incorporating these materials in the construction process, healthier and more sustainable buildings that offer an ideal living space for occupants, respecting the environment, can be built.
Figure 6 shows the trend in the ideal energy needs required by envelopes with different stratigraphies as studied in the cases of winter heating, summer cooling, and total needs. From the graph it is observed that the summer cooling needs are lower than that of winter heating and are less influenced by the transmittance of the walls.
On the contrary, winter needs follow the variation in the transmittance of the different walls. This can be observed from the graphs reported, respectively, in Figure 6 and Figure 7. Figure 7 shows the variation in the performance of the different stratigraphies from the point of view of thermal transmittance, the periodic thermal transmittance, and the surface mass of the walls studied. From the trend of the three parameters, it can be seen how the variation in the surface mass of the wall affects the trend of both thermal transmittance and periodic thermal transmittance.
Figure 8 shows how the thermal transmittance varies according to the different thicknesses of the different types of walls used in the simulations. It can be seen that thickness and the performance in terms of isolating thermal performance do not have a direct correlation, in fact, it can be observed that the reduced thickness walls such as W09, W10, W11, and W12, have the lowest values of transmittance between the twenty types of walls examined.
Finally, in Figure 9 the comparison between the thermal conductivity of the different materials used and their density is shown. It can be observed that some of the used materials have thermal conductivity values strongly influenced by density (for example see M01 or M02), while others such as M11, M12, M22, and M23 are influenced much less.
Indeed, the thermal performance of natural materials is not extremely high if compared with other non-natural materials. However, in any case, it must be considered that the values found are also good. Furthermore, if further aspects are taken into account, such as environmental goals that are not a focus in this work, there is undoubtedly an advantage in their use.

4. Conclusions

In this paper, the use of innovative locally sourced natural building materials has been evaluated from the point of view of energy performance. A numerical simulation aimed at evaluating the energy request of the case study BEST CASE ANSI/ASHARE Standard 140-2017 140 for reaching, by heating or cooling, an internal set point temperature typical of the Mediterranean climate has been implemented.
The numerical simulation has been performed for 20 different walls that include stratigraphies consisting entirely of natural materials, stratigraphies consisting exclusively of conventional materials, and mixed stratigraphies. The output of the numerical simulation is the number of days per month when the use of heating/cooling systems is necessary to reach the fixed internal set point temperature, together with the energy monthly request.
Results can be summarized as follows.
  • The surface mass of the building element and the position of the insulating layers within the wall play a crucial role in the energy performance of the wall.
  • For the Mediterranean climate assumed in the simulations, a building solution based on the W04 typology best balances the needs of heating and cooling energy in a building used 365 days/year; the result could change if the building is used mainly in the winter or summer.
  • In general, the performance of walls with innovative natural materials layers and that of walls with conventional materials layers does not vary appreciably in terms of the thermal energy required for heating or cooling.
Only the ideal energy requested by the internal environments to maintain the chosen thermo-hygrometric conditions has been evaluated, and the use of a system for the generation of thermal or cooling energy has not been accounted for. This aspect will be addressed in future research with the aim of maximizing the self-consumption of energy produced by a RES (Renewable Energy Source) during the air conditioning of the internal environments.
In conclusion, from the point of view of the energy balance applied to the building only, natural and traditional materials did not show significative difference in terms of energy needs for heating in the winter and cooling in the summer. In fact, the need for energy, evaluated according to the legislative procedures that most of the buildings must today follow in Italy, was very similar. To appreciate the global advantages that natural materials can give, it is necessary that the verification and certification procedures turn to the environmental energy aspects by evaluating the reduced emissions for their production through the analysis of the life cycle. In our case, however, there are some situations in which it may not be convenient to perform an LCA:
Lack of data: An LCA requires a large amount of accurate data. If enough data is not avaliable, or if the available data is not reliable, the LCA may not provide precise results.
High costs: LCA can be expensive in terms of time and resources. If the benefits expected from an LCA do not justify the costs, it may not be convenient to perform it.
Complexity of the product: If the product or service is extremely complex, with many different components and complicated production processes, the LCA could become too complex and difficult to manage. The materials studied are currently in the state of prototype and have no codified production processes, consequently it has been chosen not to perform the LCA as this could lead to conflicting results. This analysis will be performed in the future when research development has clearly coded production processes and supply for raw materials, which today are not known for our materials.

Author Contributions

Conceptualization, C.C.M., G.C. and A.F.; methodology, C.C.M., G.C. and A.F.; numerical analysis, C.C.M.; investigation, C.C.M. and G.C.; data curation, C.C.M. and G.C.; writing—original draft preparation, C.C.M. and G.C.; writing—review and editing, C.C.M., G.C. and A.F.; funding acquisition, G.C. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by POR FESR 2014/2020—ASSE PRIORITARIO I “RICERCA SCIENTIFICA, SVILUPPO TECNOLOGICO E INNOVAZIONE”, CUP F21B17000750005”, and This study was carried out within the “e.INS—Ecosystem of Innovation for Next Generation Sardinia”, funded by the Italian Ministry of University and Research under the Next-Generation EU Programme (National Recovery and Resilience Plan—PNRR, M4C2, INVESTMENT 1.5—DD 1056 of 23 June 2022, ECS00000038), and the “NEST-Network 4 Energy Sustainable Transition”, funded by the Italian Ministry of University and Research under the Next-Generation EU Programme (National Recovery and Resilience Plan). This manuscript reflects only the authors’ views and opinions, neither the European Union nor the European Commission can be considered responsible for them.

Data Availability Statement

The data presented in this study are available on request from the corresponding authors. The data have not been included for not weighing the paper.

Conflicts of Interest

The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

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Figure 1. Walls stratigraphies used in the numerical simulation modeling.
Figure 1. Walls stratigraphies used in the numerical simulation modeling.
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Figure 2. Axonometric view and planimetric view of the BEST CASE ANSI/ASHARE Standard 140-2017 140 [26].
Figure 2. Axonometric view and planimetric view of the BEST CASE ANSI/ASHARE Standard 140-2017 140 [26].
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Figure 3. Comparison of the number of cooling days needed to obtain the set point temperature, as a function of the stratigraphies.
Figure 3. Comparison of the number of cooling days needed to obtain the set point temperature, as a function of the stratigraphies.
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Figure 4. Comparison of the number of heating days needed to obtain the set point temperature, as a function of the stratigraphies.
Figure 4. Comparison of the number of heating days needed to obtain the set point temperature, as a function of the stratigraphies.
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Figure 5. Comparison of monthly energy request for heating and cooling.
Figure 5. Comparison of monthly energy request for heating and cooling.
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Figure 6. Comparison of primary energy need to square meters per year for heating, cooling, and total with the different walls used.
Figure 6. Comparison of primary energy need to square meters per year for heating, cooling, and total with the different walls used.
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Figure 7. Comparison of thermal transmittance, periodic thermal transmittance, and superficial mass of the walls.
Figure 7. Comparison of thermal transmittance, periodic thermal transmittance, and superficial mass of the walls.
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Figure 8. Comparison of thermal transmittance and thickness of the walls.
Figure 8. Comparison of thermal transmittance and thickness of the walls.
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Figure 9. Comparison of thermal conductivity and density of materials used in to energy simulations for the walls.
Figure 9. Comparison of thermal conductivity and density of materials used in to energy simulations for the walls.
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Table 1. Physical and mechanical properties of materials.
Table 1. Physical and mechanical properties of materials.
IDMaterialρ * [kg/m3]λ ** [W/m2K]cp *** [J/kgK]μ ****
[-]
I.n.l.s.
(Innovative natural locally sourced)
Load bearingM01Sardinian Maritime Pine CLT—3 layer—60 mm thick
Board class C16 *****
EI ****** = 138,667 MNmm2/m
491.70.11160040
M02Sardinian Maritime Pine CLT—3 layer—100 mm thick
Board class C16 *****
EI ****** = 1,109,333 MNmm2/m
491.70.11160040
Insulating
/
finishing
M03Sheep wool mat (Sardinian)30.0820.0368605
M04Rammed Earth panel1054.430.15386010
M05Slaked lime + hemp fibers459.0580.1093994040
M06Sardinian Maritime Pine board5500.15160040
Already availableLoad bearingM07Lightweight concrete half-solid block (450 × 295 × 195 mm)
fbk ******* > 15 N/mm2
11660.5079209
M08Hollow brick block (300 × 250 × 250 mm)
fbk ******* > 15 N/mm2
6930.3189209
M09Hollow brick block (300 × 120 × 250 mm)
fbk ******* > 5 N/mm2
7170.38649209
M10Hollow brick block (250 × 80 × 250 mm)
fbk ******* > 2 N/mm2
7750.49209
Insulating
/
finishing
M11Sheep wool mat300.0562586010
M12Expanded cork panels with binders1300.045210015
M13Plasterboard 7300.2100010
M14Gypsum fiber board10180.25100010
M15Wood fiber panel 1100.038210040
M16OSB panel 6500.13169930
M17Lime-based plaster18301.28100015
M18Lightweight lime-based plaster11500.6383012.5
M19Lime + concrete mortar18000.9100020
M20Air gap 20 mm—horizontal flow1.230.1091210081
M21Air gap 50 mm—horizontal flow1.230.272810081
M22Air gap 60 mm—horizontal flow1.230.3273610081
I.n.l.s.Insulating
/
finishing
M23LC—Luffa Clay panel397.600.13986010
M24JC—Jute Clay block786.810.11886010
M25JCP Jute fiber + Clay plaster1054.430.15386010
M26JW—Jute and Wool fiber 20.140.04386010
* density; ** thermal conductivity [55,56,57,58,59,60]; *** specific heat; **** hygroscopic resistance factor [58,59,61]; ***** according to [62]; ****** effective bending stiffness; ******* characteristic compressive strength.
Table 2. Composition and layer thickness of the stratigraphies.
Table 2. Composition and layer thickness of the stratigraphies.
ID Wall Layer 1Layer 2Layer 3Layer 4Layer 5Layer 6Layer 7
W01externalM13
1 cm
M12
10 cm
M07
30 cm
M14
2 cm
internal
W02M17
1 cm
M12
10 cm
M08
30 cm
M19
2 cm
W03M17
1 cm
M12
6 cm
M07
30 cm
M12
4 cm
M19
2 cm
W04M17
1 cm
M12
6 cm
M08
30 cm
M12
4 cm
M19
2 cm
W05M19
1 cm
M12
10 cm
M19
1.5 cm
M09
12 cm
M21
5 cm
M10
8 cm
M19
1.5 cm
W06M19
1 cm
M03
10 cm
M19
1.5 cm
M09
12 cm
M21
5 cm
M10
8 cm
M19
1.5 cm
W07M19
1 cm
M09
12 cm
M12
10 cm
M10
8 cm
M19
1.5 cm
W08M19
1 cm
M09
12 cm
M11
10 cm
M10
8 cm
M19
1.5 cm
W09M19
1 cm
M12
10 cm
M01
6 cm
M11
8 cm
M15
1.25 cm
M15
1.25 cm
W10M19
1 cm
M12
10 cm
M01
6 cm
M04
8 cm
M19
1.5 cm
W11M17
0.3 cm
M13
1 cm
M05
10 cm
M02
10 cm
M18
6 cm
M15
1.25 cm
M15
1.25 cm
W12M22
1.5 cm
M14
2 cm
M02
10 cm
M11
10 cm
M15
1.25 cm
M15
1.25 cm
W13M19
1.5 cm
M12
10 cm
M02
10 cm
M11
8 cm
M15
1.25 cm
M15
1.25 cm
W14M22
1.5 cm
M14
2 cm
M02
10 cm
M11
10 cm
M16
2.4 cm
W15M19
1.5 cm
M09
12 cm
M23
10 cm
M10
8 cm
M19
1.5 cm
W16M19
1.5 cm
M09
12 cm
M24
10 cm
M10
8 cm
M19
1.5 cm
W17M19
1.5 cm
M09
12 cm
M25
10 cm
M10
8 cm
M19
1.5 cm
W18M19
1.5 cm
M09
12 cm
M26
10 cm
M10
8 cm
M19
1.5 cm
W19M19
1.5 cm
M12
10 cm
M01
6 cm
M26
10 cm
M15
1.25 cm
M15
1.25 cm
W20M19
1.5 cm
M12
10 cm
M02
10 cm
M26
10 cm
M15
1.25 cm
M15
1.25 cm
Table 3. Energetic and acoustic properties of building stratigraphies.
Table 3. Energetic and acoustic properties of building stratigraphies.
IDMs [kg/m2]U [W/(m2K)]YIE [W/(m2K)]Rw [dB]Π [kg/(sm2Pa)] E-11k1 [kJ/m2K]
W1417.100.330.03524.2158.44
W2275.200.300.03484.2151.32
W3417.100.330.01524.2135.78
W4275.200.300.02484.2136.38
W5233.100.320.05474.8251.10
W6223.110.270.05466.3551.30
W7215.040.340.13465.1356.56
W8205.040.400.21465.8857.35
W990.150.200.03653.8118.83
W10133.230.250.05422.6037.95
W1196.130.260.06392.4330.27
W1282.800.240.06383.4022.68
W13109.820.200.02402.9218.49
W1476.040.240.05373.1525.20
W15241.80.700.30485.8857.36
W16280.70.6400.203495.8855.50
W17307.50.7310.209505.8854.81
W18204.10.3290.165465.8857.28
W1989.80.1820.0276518.3718.37
W20109.40.1710.014412.8318.11
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Mastino, C.C.; Concu, G.; Frattolillo, A. Energetic Performance of Natural Building Materials: Numerical Simulation and Experimental Evaluation. Energies 2024, 17, 768. https://doi.org/10.3390/en17040768

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Mastino CC, Concu G, Frattolillo A. Energetic Performance of Natural Building Materials: Numerical Simulation and Experimental Evaluation. Energies. 2024; 17(4):768. https://doi.org/10.3390/en17040768

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Mastino, Costantino Carlo, Giovanna Concu, and Andrea Frattolillo. 2024. "Energetic Performance of Natural Building Materials: Numerical Simulation and Experimental Evaluation" Energies 17, no. 4: 768. https://doi.org/10.3390/en17040768

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