Enhancing Energy Efficiency in Moroccan Construction through Innovative Materials: A Case Study in a Semiarid Climate

Abstract

Rising global energy demand has intensified the need for sustainable building practices and reduced energy consumption in the construction sector. This study investigates the energy-saving potential of integrating innovative materials into building wall structures in semiarid climates. Specifically, we examine the combination of thermal insulation made from recycled textile waste and phase change materials (PCMs) in exterior walls. Using the dynamic simulation tool TRNSYS, we analyzed heat transfer through the modified wall assembly under semiarid climate conditions typical of Marrakech, Morocco. Our results show that this “bioclimatic” design significantly impacts cooling loads more than heating demands. The modified building achieved a 52% reduction in summer energy usage compared to a conventional reference building. This energy saving translates to a 39% decrease in greenhouse gas emissions. Importantly, this study confirms that this configuration maintains thermal comfort for occupants, with particular effectiveness during the hot summer months when cooling demands are highest.

1. Introduction

The built environment significantly contributes to global energy consumption and carbon emissions, with buildings accounting for over 30% of global energy use and approximately 26% of total carbon dioxide emissions [1]. Carbon dioxide, a significant greenhouse gas, leads to climate change and can persist in the atmosphere for up to 200 years.

The energy sector faces increasingly complex and interconnected challenges across economic, geopolitical, technological, and environmental domains. The COVID-19 pandemic has further transformed this landscape, profoundly impacting societal behaviors and various sectors, including energy. The widespread shift towards remote work has significant implications for energy consumption patterns, potentially transferring substantial energy use from commercial to residential buildings [2]. As people spend more time at home, their energy consumption is likely to increase due to the heightened desire for comfortable indoor environments. This comfort is often achieved through increased use of lighting, air conditioning, heating, and ventilation systems, leading to a surge in residential energy demand. Consequently, this shift presents new challenges for energy efficiency, grid management, and sustainability efforts, necessitating innovative solutions to balance occupant comfort with energy efficiency and sustainability goals. The emergence of new environmental and economic constraints is driving the design of low-environmental-impact buildings that must meet stringent energy efficiency standards while ensuring healthy and comfortable indoor climates. Consequently, ongoing research in building energy efficiency aims to develop new materials capable of providing better building envelopes in terms of efficiency and durability.

Therefore, the question that arises here is the following: What is the optimal envelope that allows for achieving reduced energy consumption? The future evolution of environmentally friendly constructions depends on the competence of architects and engineers in creating buildings that use low energy, emit low carbon, and offer good levels of thermal comfort.

Incorporating thermal insulation into building envelope structures is a widely interesting strategy for enhancing energy efficiency. This approach is favored because insulation effectively reduces long-term energy expenses. Several studies have evaluated the thermal performance of insulation materials, taking into account various economic factors and climatic conditions [3,4,5,6,7,8,9]. For instance, Aditya et al. [10] conducted a comprehensive review of building insulation materials, their properties, and applications across different climate zones, highlighting the importance of climate-specific insulation strategies. Schiavoni et al. [11] compared different insulation materials based on their thermal properties, environmental impact, and cost-effectiveness, offering valuable guidance for material selection in diverse climatic contexts. Chihab et al. [12] focused specifically on hot climates, examining the thermal performance of multilayer hollow clay brick walls with various insulation configurations. Using Marrakesh as a case study and employing finite element analysis, the researchers made several significant findings. Firstly, they found that increasing wall emissivity significantly increased heat load. However, more importantly, they demonstrated that filling wall cavities completely with insulation materials led to notable improvements: it delayed temperature peaks by 2.3 h, reduced the decrement factor by 43%, and decreased total thermal load by 28% compared to traditional air-filled cavities.

Phase change materials (PCMs) have emerged as a promising solution for enhancing building energy efficiency. These materials offer unique thermal management capabilities through their ability to store and release latent heat during phase transitions, typically between solid and liquid states [13]. The integration of PCMs into building envelopes—including walls, floors, ceilings, and facades—has been extensively researched due to their potential to optimize energy usage and costs [14]. Furthermore, PCMs can store low-cost energy during off-peak periods and release it when needed, thereby effectively reducing overall energy expenses while requiring minimal structural alterations [15].

Additional benefits of PCMs include ease of implementation, low volume requirements, and the ability to increase a building’s thermal storage potential [16,17]. Moreover, the energy density of PCM per unit volume surpasses that of sensible heat materials by factors ranging from 5 to 14 [18], thus enabling precise control over the daily fluctuation of indoor temperature [19].

However, the effectiveness of PCMs depends on various factors, such as local climate conditions, specific phase change temperature, building parameters, and strategic placement within the envelope [20]. Although PCMs typically require encapsulation to prevent leakage and extend their lifetime, which can increase costs, their successful application in reducing cooling and heating loads across various climate zones worldwide demonstrates their potential [21].

Despite these challenges, recent advancements in PCM technology have led to the development of more efficient and cost-effective solutions. For instance, researchers have explored novel encapsulation techniques and composite PCMs to enhance thermal conductivity and cyclic stability [22]. Additionally, the integration of PCMs with other passive cooling strategies, such as night ventilation and solar shading, has shown synergistic effects in improving overall building energy performance [23].

Extensive research has demonstrated the significant impact of phase change materials (PCMs) on building energy efficiency and indoor thermal comfort across diverse climate zones [24,25,26,27]. Kenzhekhanov et al. [28] conducted a comprehensive investigation in nine subarctic towns, examining the thermal behavior and energy performance of a four-story residential building incorporating PCMs. Their findings revealed that PCMs with melting temperatures of 23 °C and 24 °C could substantially enhance building energy efficiency, resulting in annual savings of up to 10,000 kWh across the entire subarctic region. In a different climatic context, Gounni et al. [29] investigated the effects of COVID-19 quarantine on energy demand and consumption in residential buildings. They compared three building prototypes—standard, insulated, and PCM-integrated houses—across six climatic zones, analyzing energy consumption during lockdown versus normal occupancy scenarios. Their results indicated that the PCM-integrated house exhibited the lowest indoor air temperature fluctuation across all climatic zones, which was attributed to its capacity to store and release heat as needed. Mehdaoui et al. [30] investigated the thermal performance of a PCM wall installed inside a small-scale prototype over 14 consecutive days. Their results showed that the installation of the PCM wall led to enhancement in thermal comfort by reducing indoor temperature fluctuations.

Furthermore, PCMs provide a notable benefit by increasing the thermal mass of building envelopes, while insulation efficiently manages solar gain within the structure. This combination significantly reduces the demand for cooling energy. Several studies have investigated the ideal placement of PCM and insulation, as well as their combined impact on a building’s thermal efficiency [31,32,33]. To maximize the advantages of PCM/insulation technologies, it is crucial to understand the optimal positioning of the PCM/insulation layer in relation to the building’s walls and roofs. Imghoure et al. [34] studied PCMs’ effectiveness in hot climates, showing that they significantly reduce indoor temperature fluctuations and enhance thermal comfort. BioPCM-Q23 improved thermal efficiency on its own, and even more when combined with insulation. A new wall design incorporating both materials revealed that placing the PCM layer on the interior surface, after the insulation, provided superior summer comfort, with a 7 h time lag and a decrement factor of 0.0015.

Previous research in building thermal performance has often approached the optimization of phase change materials (PCM) and insulation as separate entities. However, our prior work has revealed a significant interdependence between these components, suggesting that their combined application merits further study [34]. This work builds on the research described in [34], focusing on the integration of PCM with thermal insulation derived from textile waste a combination previously identified as particularly effective. The optimal configuration, as suggested by earlier findings, involves placing the PCM layer on the interior surface, behind the insulation layer. In this study, we extend our study to evaluate the thermal performance of this wall configuration at the building scale under real-world conditions and occupancy scenarios.

To gain deeper insights into the thermal behavior of this high-performance PCM-insulation system, we conducted dynamic building simulations using TRNSYS. Our approach incorporated several considered assumptions to ensure a more accurate representation of the building’s thermal performance under semiarid climate condition of Marrakech. This research aims to enhance our understanding of how the combination of PCM with advanced insulation materials can lead to more energy-efficient and sustainable building designs.

2. Model Description

To better assess and understand the thermal behavior of the association of PCM with a highly insulating material, we adopted an approach based on a dynamic simulation of a building in real conditions. This study incorporates several assumptions to simulate the building’s thermal performance as realistically as possible, which will be detailed in the following section.

The dynamic thermal simulation at the scale of the representative building allows for the contextualization of energy consumption evaluation in real-scale buildings. It considers the local climate factors such as irradiation and wind, as well as interactions between the building walls, the environment, the internal loads from occupants, and other essential parameters. This approach aims to better represent reality and quantify potential energy savings resulting from the integration of PCM in the structure of exterior walls.

The modeling of the building in question was carried out in several main steps and based on various assumptions. The steps followed will be detailed in the next section.

2.1. Methodologies

2.1.1. Prototype of the Studied Buildings

▪

Reference building

The initial step in our modeling process involves defining the geometry of the reference building and establishing its thermal zones. Using AutoCAD software, we created a precise model that accurately represents the building’s external dimensions and interior layout (Figure 1).

This study focuses on an 80 m² apartment. The architectural plans (Figure 1) detail all construction elements, including load-bearing walls, partitions, and both exterior and interior openings. The apartment consists of a living room, two bedrooms, a bathroom, a kitchen, and a hallway.

To ensure accurate thermal modeling, we utilized the thermal properties of building envelope materials as reported in the recent study by Gounni et al. [29]. This approach allows for a realistic representation of heat transfer through the building’s structure.

This model serves as the foundation for our subsequent analyses, enabling us to evaluate the impact of innovative materials on the building’s thermal performance and energy efficiency.

▪

Building with PCM and Super Insulation

The building with phase change materials (PCM) and super insulation, later referred in this manuscript to as a bioclimatic building, is constructed using the same materials as the reference building, with the addition of two integrated layers within the exterior wall structure. The first layer comprises PCM, followed by a layer of thermal insulation made from recycled textile waste (Wr). This configuration was chosen based on previous research [34], which identified it as optimal for enhancing energy performance. By integrating these innovative materials, we aim to improve the building’s thermal regulation and energy efficiency compared to the reference building.

2.1.2. Meteorological Data

The climate analyzed in this study corresponds to that of Marrakech city, known for its semiarid weather conditions, which provides thermally uncomfortable climatic situations between the winter and summer seasons, which generates significant heating and cooling needs by this region.

In Figure 2, the evaluation of ambient temperature and incident global radiation intensity on a horizontal plane is presented, utilizing data sourced from the METEONORM database for a typical meteorological year. Notably, this climate zone experiences its highest temperature and radiation levels during July, signifying it as the peak of the year’s heat. Conversely, December, January, and February emerge as the coldest months, with low levels of sun radiation.

2.1.3. Simulation Assumptions

A transient simulation utilizing TRNSYS software was used in this study to measure the energy efficiency of the building. The model featured the full structure as well as energy-saving techniques. The cell model was created in TRNBUILD (type 56) to input the essential building simulation data, incorporating details from the envelope description, such as material properties, thickness, layers, thermophysical parameters, windows, and infiltration data. Throughout the year, the structure is modeled in mono-zones with a one-hour time step (0 to 8760 h) utilizing Marrakech’s varied climatic data. Convective radiative exchanges are considered. The external surface of walls and roofs is expected to have an absorption coefficient of 0.7 and an emissivity coefficient of 0.9. Equation (1) is used to calculate the convection coefficients of internal walls and surfaces.

$$h_{inside}=C{\left(T_{surf}-T_{air}\right)}^n$$

(1)

The values of C and n, which depend on the surface type, are indicated in

Table 1. Internal parameters for thermal transfer coefficient calculation.

Surface Type	C (W·m−2·Kn−1)	n
Roof $T_{surf}-T_{air}>0$	1.07	0.31
$T_{surf}-T_{air}<0$	2
Wall -	1.60	0.30
Ground $T_{surf}-T_{air}>0$	2	0.31
$T_{surf}-T_{air}<0$	1.70

.

The convective heat transfer coefficient for the external surfaces is determined using the following correlation, which considers the wind speed $V_{wind}$.

$$h_{c,ou}=4.955+1.44V_{wind}$$

(2)

The cell temperature was set at 20 °C, while the relative humidity was maintained at 50%. Each wall has an infiltration factor of 0.5 ACH [36].

Regarding the occupancy scenario, the building is considered inhabited by a family of three people: two adults and one child. An internal heat production related to lighting is considered equal (6 W/m²). The lighting remained active when the illuminance (L) was below 120 W/m² and was turned off when the illuminance exceeded 200 W/m². Regarding appliances, the internal thermal loads were influenced by the area-related equipment heat gain, according to SIA2024 guidelines for the residential category. The convective power accounted for 23.04 KJ/h, while the radiative power contributed 5.76 KJ/h, both during the occupancy period. Thus, the internal gains made by the occupants were counted by 70 W per person.

During each simulation time step, this analysis is conducted to estimate the energy amount needed to sustain a predefined temperature in accordance with Moroccan requirements. The heating thermostat setting is 20 °C, while the cooling setting is 26 °C. TRNSYS type 77 is used to execute ground coupling on the building, according to the Kusuda correlation, which is written as follows:

$$T=T_{mean}-T_{am}*exp\left[-depth*{\left({\displaystyle \frac{\pi }{365{\alpha }_{soil}}}\right)}^{0.5}\right]*\cos \left\{{\displaystyle \frac{2\pi }{365}}*\left[t_{now}-t_{shift}-{\displaystyle \frac{depth}{2}}*{\left({\displaystyle \frac{365}{\pi {\alpha }_{soil}}}\right)}^{0.5}\right]\right\}$$

(3)

Correlation (Equation (3)) focuses on the vertical distribution of soil temperature, considering key parameters such as the mean soil surface temperature for the entire year, the amplitude of soil surface temperature variations throughout the year, the time difference between the start of the calendar year and the point when the minimum surface temperature occurs, and the thermal diffusivity of the soil. In cases where the mean surface temperature (T_mean) is not directly measured, it can be approximated as the average annual air temperature. Additionally, the Type 69b component is utilized to determine the effective temperature of the sky. This effective sky temperature enables the calculation of the exchange of long-wave radiation between the building’s exterior surfaces and the atmosphere.

$$T_{sky}={\epsilon }_{sky}^{{\displaystyle \frac{1}{4}}}{T}_{amb}$$

(4)

with ${\epsilon }_{sky}={\epsilon }_{0,sky}+\left(1.0-{\epsilon }_{0,sky}\right)f_{cloud}{\epsilon }_{cloud}.$

Different methods for evaluating atmospheric emissivity under clear sky conditions, ${\mathsf{\epsilon }}_{0,\mathrm{sky}}$, can be found in the literature [37], each of which leads to a distinct mathematical correlation. Among these correlations, we selected the Martin and Berdahl equation (corrected) because it stands out as the only one that interpolates experimental data with a nonlinear equation, potentially offering a more comprehensive description of the phenomenon.

$${\epsilon }_{0,sky}=0.711+0.0056T_{dp}+0.000073T_{dp}^{2}60.013\cos \left(2\pi {\displaystyle \frac{time}{24}}\right)+0.00012\left(P_{atm}-P_0\right)$$

(5)

The dew point temperature was calculated using an integrated type 33e (psychrometric module). Type 33e computes various thermal properties of moist air, encompassing humidity, wet bulb temperature, enthalpy, moist air density, dry air density, relative humidity percentage, and dew point temperature, among others.

For the modeling of phase change material in wall constructions, we used the Type 399. Figure 3 illustrates the tools used in the Trnsys dynamic simulation platform developed.

3. Validation of Our Model

To test and validate our numerical model, we simulated various scenarios for a house model. Numerical models can be validated using analytical approaches, comparative tests with other numerical models, or experimental results. In this study, we validate our proposed numerical model by comparing our results with existing numerical codes and experimental data, specifically those obtained by Gounni et al. [29] and Mourid et al. [38].

▪

1st Validation: Numerical Results from Gounni et al. [29]

To validate the proposed TRNSYS tool, we compared our model’s results with those from the study conducted by Gounni et al. [29]. We used the same literature databases, assumptions, and modeling conditions for this comparison. Figure 1 depicts the floor plan of the apartment.

Study Parameters:

• Location: Tangier, northern Morocco.
• Apartment size: 80 m².
• House type: “PCM house” (constructed with standard materials plus a paraffin-type phase change material layer in exterior walls and roof).
• Occupancy scenario: Unoccupied throughout the year.
• Setpoint temperatures: 15 °C (heating) and 30 °C (cooling).

Figure 4 shows the evolution of the exterior surface temperature over time. Our results demonstrate good agreement with those obtained by Gounni et al. [29], confirming the accuracy and effectiveness of our developed code. The mean relative error does not exceed 0.32%.

▪

2nd Validation: Numerical Results from Mourid et al. [38]

To further validate our TRNSYS-based numerical model, we conducted an experimental study using a full-scale prototype.

Experimental Setup:

• Location: Faculty of Sciences Ain Chock, Casablanca, Morocco (latitude 33°36′ N, longitude 07°36′ W, Altitude 57 m).
• Building size: 9 m² area, approximately 27 m³ volume.
• Orientation: North-facing entrance.
• Window: Single glazing with aluminum frame, 1 m × 1 m.
• Study period: 20 April to 22 April 2014 (passive period).
• Temperature measurement: Sensors with ±0.35 °C accuracy.

For more details on the experimental setup and results, refer to Reference [38].

Figure 5 presents a comparison between the simulated and experimental temperature data over the two-day period. The results show good agreement between the model predictions and actual measurements. The relative error ranges from 1.21% to 3.75% throughout the measurement period. The slight differences observed between the simulated and experimental results are mainly due to the inherent limitations of the measuring instruments and possible environmental factors that were not considered in the simulation.

The validations conducted demonstrate the accuracy and reliability of our TRNSYS-based numerical model. The comparison with the numerical results from Gounni et al. [29] shows excellent agreement, with a mean relative error below 0.32%, while the experimental validation based on Mourid et al. [38] yields relative errors between 1.21% and 3.75%. These results confirm the robustness of our model for accurately simulating the thermal behavior of buildings.

4. Results and Discussion

4.1. Thermal Behavior Analysis of Studied Configurations

The calculation results, illustrated in Figure 6, demonstrate that integrating PCM with insulation into the wall structure significantly affects the building’s internal temperature profile. This configuration reduced internal temperature fluctuations throughout the year.

To conduct a more in-depth examination of the interior air temperature for both configurations, we focused on two-day periods in winter (15–17 January) and summer (15–17 July).

The results indicate that our bioclimatic configuration has significant potential for practical application. Figure 7A,B show temperature estimates for the winter and summer seasons, respectively. The bioclimatic building shows notable benefits in summer, with indoor air temperatures reduced by 2 °C to 5 °C compared to the reference building.

However, the thermal performance of the bioclimatic building in winter is often insufficient. The interior temperature remains well below the set temperature. This may be due to the combination of insulation and PCM reducing the transmission of solar energy to the interior, which significantly affects the phase transformation of the PCM.

4.2. Analysis of Heating and Cooling Requirements

The aim is to study the impact of the proposed wall configurations on energy consumption. Several methods are used to estimate the building’s energy demand, such as degree-day and degree-hour methods and the instantaneous transmission load calculation method. The latter is considered the simplest and most accurate method. In determining the daily heating/cooling charges, Daouas [39] and Ozel [40] propose a technique that revolves around quantifying the heat transmission between the wall and the indoor environment. The calculation of heat transfer loads is achieved through the utilization of the following equation:

$$q_i=h_i\left(T_{x=L}-T_{int}\right)$$

(6)

where h_i is the heat transfer coefficient by indoor convection, $T_{x=L}$ is the temperature of the inner surface, and Tin is the indoor temperature of thermal comfort. The instantaneous heat load is calculated using the 15th day of every month as a representative, typical day throughout the year. The total daily load is obtained by integrating the instantaneous heat flow of the inner surface over a period of 24 h. To determine the annual heating and cooling loads, the daily transmission loads are calculated separately, and then they are added for the entire year. This method ensures accurate assessment of the overall energy demands for heating and cooling purposes.

• During summer:

(T_x=L − T_int) > 0: The interior is overheated, and the calculated flux represents the energy consumed by the cooling system to maintain the comfort temperature.

• During winter:

If T_x=L − T_int) > 0: The interior is losing thermal energy through the wall. Thus, the calculated flux represents the energy consumed by the heating system to maintain the comfort temperature.

Figure 8a shows the monthly heating and cooling demands for a bioclimatic building and a reference building. The comparison of heating and cooling needs for both buildings shows that the bioclimatic building requires less energy for heating and cooling compared to the reference building in all months of the year.

During the summer period, consumption is highest in August during the cooling season. The reference building consumes almost 70 kWh for cooling in August, while the bioclimatic building consumes only 36 kWh.

• During the heating period, January exhibits the highest energy consumption.

The heating energy consumption of a bioclimatic building in January was slightly lower than the baseline.

To better estimate the energy savings that a bioclimatic building could provide, Figure 8b represents the relative energy savings in terms of electricity consumption. It can be observed that the energy consumption intensities of a bioclimatic building are significantly reduced compared to the reference building, especially during the summer period with a gain of 52%.

In summary, the results indicate that the integration of phase change materials (PCMs) with insulation in the walls led to significant energy savings. This was achieved by shortening the winter heating period through effective heat conservation during the phase change and limiting the cooling period by minimizing excessive overheating from solar and internal gains as much as possible.

Marrakech’s semiarid climate, characterized by hot summers (ranging from 25 °C to 38 °C, often exceeding 40 °C), significant diurnal temperature variations, and high solar radiation (approximately 2900 sunshine hours annually) significantly influences the effectiveness of our bioclimatic design, particularly the combination of phase change materials (PCMs) with insulation. The PCM-insulation system is optimized for such conditions where cooling needs are predominant, especially from May to October.

In Marrakech’s hot summers, the PCM effectively absorbs excess heat during the day, preventing indoor overheating, while the insulation layer minimizes external heat gain. The substantial temperature drop at night allows the PCM to release the stored heat, readying the system for the following day. This interaction is demonstrated by a marked reduction in cooling energy consumption, from 70 kWh to 36 kWh in August, reflecting a 48.6% decrease (Figure 8a). The high solar radiation in Marrakech enhances the PCM’s efficiency by ensuring consistent phase changes.

In winter, while the PCM still contributes to thermal management, its impact is less pronounced due to reduced solar radiation affecting its phase change process. This climate-specific efficiency indicates that the PCM-insulation combination is particularly beneficial in regions with similar semiarid climates or those dominated by cooling needs, such as hot arid or certain subtropical zones.

For other climate zones, the PCM’s performance could vary. In temperate climates with moderate temperatures and less extreme diurnal variations, the PCM’s phase change properties might be less effective, necessitating adjustments to the insulation to balance both heating and cooling needs. In cold climates, the PCM’s melting point would need to be tailored to manage lower temperatures effectively, potentially requiring enhanced insulation to reduce heating demands. Conversely, in tropical climates with consistently warm temperatures and minimal variation, the PCM might primarily address cooling needs, but its overall effectiveness could be limited by the lack of significant temperature swings. Therefore, while the PCM-insulation approach shows considerable promise in semiarid climates like Marrakech, adjustments to the PCM’s melting point and insulation properties would be necessary to optimize performance across different climate zones.

4.3. Analysis of Greenhouse Gas Emissions (GHG)

This study extends our previous research by integrating environmental aspects into the evaluation and improvement of building energy efficiency. We focus on the impact of heating and cooling demands on greenhouse gas emissions.

Annual GHG emissions from electricity consumption are calculated using the annual electricity consumption and the GHG emission factor. This factor represents the equivalent CO₂ emissions generated per kilowatt-hour of energy consumed.

Figure 9 illustrates the calculated GHG emissions for both the reference case and the bioclimatic building in Marrakech. The results show that the bioclimatic building achieved a significant net reduction of 36% in emissions compared to the reference case. This reduction can be attributed to the superior thermal performance of bioclimatic buildings, which enables them to emit less CO₂ than conventional buildings.

5. Economic Analysis

While the thermal and energy performance of the innovative bioclimatic (PCM with textile material Wr) wall demonstrates promising results, a comprehensive economic assessment is essential to determine its practical applicability in the construction industry. This evaluation is crucial for stakeholders, including architects, engineers, and building owners, to make informed decisions about adopting this technology. We primarily utilize two key approaches: life-cycle cost analysis (LCCA) and payback period evaluation.

▪

Life-Cycle Cost Analysis (LCCA)

This method considers the total cost of ownership over the entire lifespan of the building, including initial investment, operational costs, and potential savings. The life cycle cost (LCC) is defined by [41]

$$LCC=IC+PWF\times EC$$

where

• IC: Investment cost (MAD);
• EC: Annual energy cost for indoor comfort (MAD);
• PWF: Present worth factor.

The present worth factor (PWF) converts future recurrent expenses to present costs, considering the economic outlook of the country. It depends on the discount rate (r) and the lifetime (N):

$$\left\{\begin{array}{c}PWF={\displaystyle \frac{{\left(1+r\right)}^N-1}{r{\left(1+r\right)}^N}}\left\{\begin{array}{c}i>gr={\displaystyle \frac{i-g}{1+g}}\\ i<gr={\displaystyle \frac{g-i}{1+i}}\end{array}\right.\\ PWF={\displaystyle \frac{N}{1+i}}i=g\end{array}\right.$$

where

• g: Inflation rate;
• i: Interest rate;
• N: Lifetime of the building.

▪

Payback Period Evaluation

This approach focuses on determining the time required for the energy savings to offset the initial investment costs. The simple payback period (PP) for the TIM-PCM wall integrated into the building envelope is calculated by [7]

PP = IC/ESC

where

• PP: Payback period;
• IC: Initial cost;
• ESC: Energy savings cost (including annual lighting savings where applicable).

Furthermore, the LCC of 2628 MAD/m² over a 9-year period indicates that the system’s long-term benefits outweigh its initial costs. This figure becomes even more favorable when considering potential increases in energy prices over time, which would amplify the cost savings provided by the bioclimatic system.

6. Potential Challenges to Implementing Novel Materials for Energy-Efficient Buildings in Morrocco

While integrating PCMs with insulation in Marrakech’s buildings offers significant benefits by improving building energy efficiency, several challenges must be addressed to ensure practical implementation. Material availability is a key concern, necessitating the development of local supply chains for innovative materials like PCMs and high-performance insulation. Morocco is making substantial strides in waste valorization, energy efficiency, and innovative material creation. A 2021 waste mapping study conducted by the United Nations Industrial Development Organization (UNIDO) [42] revealed an annual potential of 83,200 tons of preconsumer textile waste generated by the Moroccan textile industry. This progress could stimulate the growth of sustainable material sectors, including construction.

Initiatives such as the textile waste recycling unit in Tangier and various projects demonstrate the country’s commitment to advancing these sectors, potentially improving the availability of innovative construction materials and enhancing local expertise in energy-efficient technologies. However, regulatory constraints and building code compliance pose additional obstacles, as current standards may not yet accommodate these new materials. Close collaboration with local authorities, regulatory bodies, and research laboratories will be essential in developing appropriate testing protocols and performance standards.

Moreover, the effective implementation of these technologies requires specific expertise, underscoring the need for targeted training programs for building professionals. Finally, further studies on the durability and long-term performance of PCMs under various climatic conditions are crucial to ensure their sustained effectiveness. By proactively addressing these challenges, we can facilitate the adoption of innovative solutions and maximize their positive impact on energy efficiency and building sustainability in Morocco.

7. Conclusions and Recommendations

In this study, we adopted a numerical approach based on a dynamic simulation of a building at real scale using Trnsys software. Several hypotheses were employed to conduct the thermal simulation of the building in a state close to reality. Our study aimed to investigate the thermal behavior and energy performance of a bioclimatic configuration, specifically the association of phase change materials (PCMs) with a super insulator.

The obtained results demonstrated the great potential of bioclimatic building design. During the summer season, the bioclimatic configuration proved highly effective in reducing indoor air temperatures over a notable range of 2 °C to 5 °C. However, in winter, this configuration did not significantly influence indoor temperatures, which remained considerably lower than the set temperature.

Furthermore, our research demonstrated that this building design leads to substantial energy consumption reduction when compared to the reference building. Particularly during the summer period, we observed a remarkable 52% reduction in energy usage. This energy-saving leads to a payback time of about 9.2 years. The adoption of the bioclimatic configuration also resulted in a substantial decrease of 39% in greenhouse gas emissions compared to a conventional reference building.

Looking ahead, our research opens up exciting avenues for further innovation in building energy efficiency. One promising direction is the exploration of microencapsulation techniques to integrate phase change materials into biobased textiles. This novel approach has the potential to significantly enhance the thermoregulating characteristics of building envelopes while reducing wall thickness and weight. By combining PCMs with textile materials, we could create multifunctional building components that not only provide excellent thermal regulation but also contribute to lightweight, sustainable construction practices.