This study presents a comparative cradle to gate life cycle assessment of four solar-powered vacuum membrane distillation (VMD) configurations. VMD including mechanical vapor compression powered with solar thermal energy for heating photovoltaic electricity for pumping exhibits the lowest impacts across several categories. This superior environmental performance is closely linked to its energy efficiency, as it achieves the lowest specific energy consumption (154.6 kWh/m3) while producing the highest water output. Furthermore, the results indicate that solar energy components, including photovoltaic panels and solar thermal collectors, are the primary contributors to the environmental footprint, representing 75–99 % of impacts across all categories. Following the finding an analysis was conducted to assess the effect of collectors type. Three types of photovoltaic panels monocrystalline silicon (sc-Si), multicrystalline silicon (mc-Si), and cadmium telluride (CdTe) and two solar thermal technologies, flat plate collectors (FPC) and evacuated tube collectors (ETC) were considered. Thin-film cadmium telluride (CdTe) PV modules consistently achieve the best environmental performance, while multicrystalline silicon (mc-Si) modules are associated with the highest emissions. For instance, the CO2 emissions per cubic meter of produced water decrease from 7.73 to 3.04 kg when thin-film CdTe PV modules are used instead of monocrystalline silicon (sc-Si) modules. The results show that flat plate collectors (FPC) perform slightly better environmentally, with reductions ranging from 1 % to 11.4 % compared to evacuated tube collectors (ETC) across several impact categories.

This study presents a combined experimental and modeling investigation of cellulose-based evaporative cooling pads, focusing on the synergistic effects of inlet air psychrometric conditions and air velocity on cooling performance. Unlike conventional studies that examine temperature, humidity, and airflow separately, this work systematically analyzes their interactions and impact on air cooling and humidification. Experiments were conducted under controlled variations of dry-bulb temperature, relative humidity, water temperature, air velocity, and water flow rate. The results show that the maximum cooling efficiency (up to 90–95%) is achieved under moderate air temperature conditions (28–34 °C), inlet water temperature ranging from 22 to 25 °C, low to medium relative humidity (30–50%), and within the studied air velocity range of 0.27–0.53 m/s. where coupled sensible and latent heat transfer mechanisms are optimized. Air velocity enhances mass transfer by renewing the air boundary layer, while favorable psychrometric conditions drive efficient evaporation. Both humidification and temperature drop are highly sensitive to the interplay of these parameters, highlighting the importance of coordinated optimization. A one-dimensional heat and mass transfer model was developed using experimentally identified heat and mass transfer coefficients. The model demonstrates reliable performance prediction under the investigated inlet humidity conditions, with MAE and RMSE values below 7% for cooling efficiency, and shows excellent agreement with measured outlet air temperatures, with MAE and RMSE values below 1 °C, indicating very low pointwise errors. Overall, the model accurately reproduces the system behavior within the studied operating range. These findings provide practical guidance for designing and operating high-efficiency evaporative cooling systems, emphasizing the importance of simultaneously optimizing air psychrometric conditions and airflow to maximize cooling and humidity control in hot and dry climates.

Because of its potential for high permeate flux, vacuum membrane distillation (VMD) holds great promise for the desalination of water. However, high heat-transfer and mass-transfer resistances limit performance and encourage membrane fouling, making practical deployment difficult. In the present work, a submerged VMD module configuration is provided, in which the membrane module is submerged in the saline feed stream. To reduce temperature and concentration polarization, mechanical agitation is also applied. When agitation is introduced, comparative measurements show a similar to 30 % increase in permeate flux compared to when it is not. This suggests that produced turbulence around hollow-fiber membranes greatly lowers temperature-polarization resistance. By operating at a vacuum pressure of 3000 Pa, which is securely below the liquid entrance pressure of around 1.2 bar, the system validates the integrity of the membrane and permits the measurement of permeability. The impacts of feed temperature were further investigated. The module obtained a permeate flux of 10.92 kg h(-)(1) m(-)(2) at 70 degrees C, and both model-based and experimental results emphasize feed temperature as a key factor influencing performance. These results show that agitation and module immersion are efficient ways to lower fouling risk and transfer resistances in VMD, providing a feasible path to increased desalination efficiency and accurate membrane characterization.

This study conducts a cradle-to-gate life cycle assessment (LCA) of a solar-powered humidification-dehumidification (HDH) desalination system using OpenLCA 2.5, focusing on two stages: manufacturing and operation. The results show that impacts such as fine particulate matter formation (PMFP), freshwater eutrophication (FEP), and terrestrial acidification (TAP) are mainly driven by the manufacturing phase, largely due to the production process of metals and polymers. Conversely, global warming (GW), fossil resource scarcity (FRP), and several other categories are dominated by the operational stage because of electricity consumption from fossil-fuel-based sources used to power pumps and blowers. Four operational scenarios were evaluated. Scenario 4, which is characterized by enhanced heat and mass transfer through water spraying and the incorporation of phase change materials (PCM), achieved the lowest energy consumption (16.8 kWh/m3) and the best overall environmental performance. Compared to the baseline scenario, it reduced GW by 54%, FRP by 12%, and TAP by 42%. Replacing fossil-based electricity with photovoltaic power reduced CO2 emissions by 92%, fossil resource scarcity (94%), and other operational emissions. However, some categories, including freshwater ecotoxicity (FETP) and human toxicity (HTPc), increased due to the environmental impacts of photovoltaic panel manufacturing and the extraction of metals and minerals used in their production. Moreover, using recycled materials further reduced GW, FRP, and TAP by 32.9%, 24.1%, and 12.4%, respectively, though HTPc rose by 10% because of toxic additives such as stabilizers and flame retardants used in the recycling process.

Adsorption refrigeration machines (ARMs) driven by low-grade thermal energy constitute an attractive alternative to conventional cooling systems. This study develops and experimentally validates a dynamic model of a two-bed silica gel–water adsorption chiller and investigates its thermal integration with a green hydrogen production unit based on water electrolysis. Unlike conventional studies considering generic heat sources, the present work specifically exploits the waste heat released by the electrolyzer to supply the desorption process, enabling the co-production of cooling and hydrogen within an integrated energy system. A parametric analysis is performed to assess the influence of desorption, adsorption, and evaporation temperatures on system performance under transient operating conditions. The results show that appropriate thermal matching between the electrolyzer heat rejection profile and the adsorption cycle allows the system to reach a maximum specific cooling power of 0.48 kW kg−1 and a coefficient of performance of 0.72. Furthermore, the proposed hybrid configuration ensures stable and quasi-continuous cooling output despite fluctuations in the electrical or solar input powering the electrolyzer. These findings demonstrate that waste heat recovery from hydrogen production can significantly enhance overall energy utilization and provide a viable solution for low-carbon cooling in multi-energy and off-grid applications.

Nowadays, there is a specific need to develop environmentally sustainable desalination methods in light of the growing environmental issues and water scarcity. In this regard, membrane distillation (MD) is an evolving and highly promising technology that efficiently and sustainably distills without causing pollution especially since this technology can work with solar energy. VMD is among the most widely recognized configurations in MD technologies. However, the coupling with solar thermal and PV energy to power VMD has been relatively understudied, and very fewer studies have focused on energetic and economic efficiency of completely autonomous VMD plants. This research presents a thermo-economic optimization for an autonomous solar-powered VMD unit. The results proved that the energy performance of the process improves with augmenting inlet temperature and increasing vacuum level on the permeate side of the membrane. Furthermore, productivity and energy performance are significantly increased by raising membrane permeability and recycling rate. In addition, it has been noted that the rejection rate should not exceed 20

Adsorption refrigeration machines (ARMs) offer a sustainable cooling solution by oper-ating with low electrical input and utilizing environmentally friendly refrigerants. Their compatibility with renewable energy sources makes them particularly suitable for inte-gration into clean energy systems, including hydrogen production processes. This study investigates the thermodynamic performance of an ARM through a parametric analysis focused on the influence of adsorption and desorption temperatures on system efficiency. The analysis is based on a dynamic thermodynamic model simulating the adsorption cycle under various temperature scenarios. Key performance indicators, such as the coef-ficient of performance (COP), cooling capacity, and thermal efficiency, are evaluated across a range of operating temperatures. Particular attention is given to the optimization of the desorption temperature, which critically affects energy consumption and the cooling demand required for hydrogen production via electrolysis or thermochemical processes. Results show that optimizing temperature parameters can significantly improve system performance. For instance, increasing the desorption temperature within an optimal range enhances the regeneration phase and maximizes the COP. The study identifies operating conditions that promote high thermal efficiency and effective coupling with hydrogen production cycles. These findings demonstrate the technical feasibility and energetic advantages of integrating adsorption refrigeration into hydrogen production systems. Such coupling not only reduces the total energy input but also supports the development of low-carbon, energy-efficient pathways for green hydrogen generation.

Vacuum membrane distillation (VMD) is a promising desalination technology, which is likely to be integrated with solar energy, and offers a sustainable solution to freshwater scarcity. However, its industrial application remains limited due to high specific energy consumption and water production costs. The key to improving VMD performance lies in enhancing the recovery of the latent heat of condensation. In this investigation, four different configurations are proposed; each differs in the method of condensation and energy recovery. The first is applied by using a basic condenser, preheating seawater with latent heat from vapor. The second is implemented by incorporating a liquid ring vacuum pump (LRVP), enabling both condensation and vacuum generation. The third is performed by coupling VMD with a heat pump, which operates by using a refrigerant fluid. Lastly, the fourth is employed by using mechanical vapor compression (MVC), where the vapor is compressed to recover heat efficiently. The results show that the VMD-MVC is the most efficient configuration, offering the lowest specific energy consumption (154.6 kWh/m3), the highest energy recovery rate (54.64%), the highest gained output ratio (GOR) of 5.52, and the lowest water production cost (4.6 USD/m3). In contrast, the VMD system coupled with a heat pump presented the highest water production cost (36.4 USD/m3) among all the evaluated configurations.

Excessive consumption of water resources is a major problem almost everywhere through the world due to the global increasiness of population and the underlying high rates of urbanization and industrialization. In this context, Solar desalination is proposed as an effective solution not only to produce water but also to mitigate the emissions of CO2, which thereby contributes to the limitation of global warming. This study presents an experiment that explores the use of solar energy in desalination systems, consisting in a parabolic dish solar concentrating "SCHEFFLER REFLECTOR" for desalination-hot water system (PDSCHWS) conducted in the weather conditions of Marrakesh in Morocco also an environmental analysis conducts to calculate the emission of CO2 and the carbon credit gained. The performance of the desalination system was achieved in real thermal conditions from January to May 2022 on several days each month. The investigated results reported that the efficiency of the system is 28.75 %. It actually produced 9000 cm3/day of distilled water with an electrical conductivity of 3.4 mu S/cm which presented a significant reduction from the initial level of 4 * 103 mu S/cm. The environmental analysis concluded that the carbon credit gained from the system is 529.69($), and the net carbon dioxide mitigation is 37.83 tons of CO2 emission over the lifetime of the system.

The phase change materials PCMs are some kind of energy storage which represents a sustainable alternative for reducing energy consumption. The incorporation of PCMs in the condensation process allows the storage and the release of large amounts of energy in the form of heat during the melting and solidification process. The objective of this study is the design of a condensation system with PCM in order to extend the operating time of the condenser and to improve the efficiency of a humidification–dehumidification desalination system. A first study was carried out to select a phase change material (PCM) well adapted to the operating conditions of the desalination system by humidification dehumidification. A eutectic organic PCM mixture (80 wt

A study is conducted on the performances of a solar powered continuous-adsorption refrigerator considering two particular days as references cases, namely, the summer solstice (June 21st) and the autumn equinox (September 21st). The cooling capacity, system performance coefficient and the daily rate of available cooling energy are assessed. The main goal is to compare the performances of a solar adsorption chiller equipped with a hot water tank (HWT) with an equivalent system relying on solar collectors with no heat storage module. The daily cooling rates for the solar refrigerator are found to be 102.4 kWh and 74.3 kWh, respectively, on June 21st and on September 21st, using a total collector’s area of 43.47 m2. The corresponding values for the adsorption chiller equipped with a hot water tank of 2 m3 (and using a total collector’s area of 72.45 m2), are 127.1 kWh and 106.13 kWh, respectively.

A dynamic model is presented for a chiller working with a composite adsorbent (silica activated carbon/CaCl2)- water pair in a solar-biomass cooling installation. The main objective is determining a link between two possible evaporator configurations and the refrigerator's performances. The two considered evaporators work at different pressure levels. The related time evolution profiles of temperature, pressure and water content are studied. More-over, the effects of hot water inlet temperature and cooling water inlet temperature on the specific cooling capacity (SCP) and coefficient of performance (COP) are predicted by means of numerical simulations. The results show that an increase in the temperature of hot water and a decrease in the temperature of the cooling water allow an increase in COP and SCP. In particular, for a hot water inlet temperature of 85 degrees C and a cooling water inlet tem-perature of 40 degrees C, the COP and Qev are 0.67 and 4.3 kW, respectively.

A continuous adsorption refrigerator, aiming for cold production to a fruit storage room installed in arid regions, is proposed. After cooling load estimation, a technical-economic study of different types of solar collectors was performed. Then, the dynamic performances of a solar-driven two-bed adsorption chiller are studied. Furthermore, this study shows that an optimal choice of the collector-type area and the operating conditions can reduce the global system cost and ensure better energy management. With 43.47 m 2 collectors’ area, a solar fraction of 55% is reached at cycle time (tcycle) 1600s; however, 49% is obtained at tcycle of 900s. With a total collectors’ area of 43.47 m2, a tcycle of 1600s and a cooling water inlet temperature (TCW,in) of 22°C, 60% of the cooling demand is solar produced. However, 57% is achieved at a tcycle of 900s, 50.61 m2 collectors’ area and TCW,in of 25°C.

This study investigates the performances of a self-sufficient greenhouse powered by a solar humidification–dehumidification desalination unit. It aims to achieve an overall integrated system that produces enough fresh water to cover the irrigation demand as well as the air humidification needs of the greenhouse. The humidification–dehumidification operation was numerically simulated using the developed model along with the greenhouse microclimate. The greenhouse model was validated through an experimental real-scale greenhouse. To make the proposed system more flexible, an auxiliary control system is used to easily monitor the greenhouse needs and ensure its satisfaction. The findings revealed that the integrated system, with its two main subsystems and its regulation device, successfully ensures the greenhouse irrigation, the humidification needs and provides an optimal plant growth. For the case study, i.e. cucurbit greenhouse situated at El Hamma (Tunisia), the desalination system can cover more than 200% of the greenhouse water irrigation needs while keeping the greenhouse inside air at a humidity level of 60% at least. The maximum productivity and the best energy efficiency are respectively 5.1 m 3 /day and 63.25%.

In this work, several configurations of seawater desalination plant by vacuum membrane distillation were presented. Two types of membranes were studied: flat membranes and hollow fiber modules. These systems use solar energy to supply the heating needs for the seawater to be desalinated. The different possibilities depend on the type of collector used (plan collector (CP), cylindro-parabolic solar collector (CPC), or solar pond (SGSP)) and the nature of the coupling of the module with the collector (integrated or separate module). The type of flow within the fibers (external–internal or internal–external) is a key parameter for the design of these configurations. The performance analysis of the different possible configurations made it possible to compare their productivity according to the type of collector used and to study quantitatively the interest of integrating a hollow fiber module within the solar collector. The study of different configurations made it possible to present the advantages and disadvantages of each configuration. This work made it possible to evaluate the annual production of desalted water by the vacuum membrane distillation; this production varies from 5 to 32.5 m3/m2.

The present study deals with heat storage in a solar-powered refrigeration system designed for indigenous products preservation in a cold room with a positive temperature. One of the key goals of this study is to show the importance of heat storage and the choice of the suitable coupling, position, and technology of thermal heat storage in these systems to ensure energy management and system operation flexibility. A new system configuration design where the direct connection between the solar collectors and the adsorption chiller used in the directly driven chiller without any heat storage module and in the classic storing system is suppressed and a new special regulation system is added to manage the temperature of the supplied water to the adsorption chiller. Under the same solar collectors' area, the new configuration design performs well than the existing configurations and offers more flexibility and stability to the system. It was found that, the heat storage, performed by a Hot Water Tank (HWT), enhances the system's cooling production time duration as well as offers stability and reduces the highly fluctuant hot water temperature in solar adsorption chillers. It's shown that the choice of the adsorption chiller cycle time duration is of great importance as well as the HWT volume on the system's performance. The study shows also that the system achieves better performances when considering a stratified HWT instead of a fully mixed HWT. Using a total solar collectors' area of 84.53 m2, a hot water tank of 3 m3, and a cycle time of 1200 s, a solar fraction of 86% is obtained when the proposed configuration is connected to the stratified heat storage technology however 80% is reached when the system is equipped with the mixed hot water tank.

Adsorption refrigeration technology such as green refrigeration method, following environmental protection and growing economic development, has received much attention. Which are considered more environmentally friendly alternatives to conventional compression refrigeration, since they can use refrigerants that do not contribute to ozone layer depletion and global warming.The silica gel -water is the adsorbent-adsorbate pair used in this paper . Compared with other adsorbents (activated carbon - methanol, Zeolite - water), silica gel-water presents the advantage of excellent physical and thermal properties of water (high latent heat of evaporation, low viscosity, high thermal conductivity , thermal stability in a wide range of operating temperature and a compatibility with several materials) as well as good adsorption property of silica gel (high adsorption/desorption rate and low generation temperature). The couple of silica gel-water can be classified as the best couple for adsorption cooling applications. This paper presents an experimental study of a solar adsorption refrigeration system for three typical days. The variation of the solar flux, the characteristic of temperatures of the solar collector as well as the temperatures of the various components of the adsorption chiller allowed seeing the effect of the solar flux on the various parameters and the performance of the adsorption chiller for two different cases : solar/aerothermal coupling and the solar /geothermal coupling system.

The lower productivity of the conventional solar still requires bringing modifications to this system. The proposed modification in this work consists of coupling water spray and ambient air injection, which may enhance the water–air surface contact area as it plays a crucial role in the performance in such a device and, consequently, increases the still performances. Response surface methodology (RSM) model is derived from an experimental test set up using the design of experiment procedure to investigate the binary interaction effects of the operating parameters, i.e., spraying height, inlet water temperature, and water and air flowrates. Based on RSM results, a simple polynomial statistical model is stated in this investigation to determine and maximize the amount of evaporated water from solar still based on the four considered input factors. An excellent fitting is attained between the predicted results derived from the statistical model and the experimental results. The performance of this model was also validated using the variance analysis approach. The findings indicate that the main influencing parameters in the order of impact on the system productivity is ambient air mass flow, saltwater temperature, sprayed water mass flow and sprayer height. The binary interaction effects of the variables were considered and illustrated for design recommendations. Within the studied ranges, the hourly productivity varies from 1.91 to 7.9 kg/h m2 for a water temperature between 40 and 70 °C.

An innovative design approach consists of using a saline water spray humidifier to improve the performance of the humidification-dehumidification water desalination system, where hot water was sprayed from the top and air was supplied from the bottom of the humidifier. Before scaling a unit of this type, it is necessary to get sufficient information about the heat and mass transfer process that occurs in the unit. A prototype desalination unit has been developed and used to fulfill the main objective of this research which is to evaluate the mass and heat transfer coefficients in the humidifier. As well, the effect of salt water flow rate, water temperature, air flow rate and position of the water spray are examined in order to optimize the operating conditions. A quadratic model estimating the performance of the humidifier was developed and validated using the design of experiment analysis and variance approach. A response surface methodology was used to correlate and assess the influence of each parameter and its interactions with the others. The results indicate that the effect of air flow rate and inlet water temperature on mass and heat transfer is greater than the height of the sprayer and the saline water flow rate. Binary interaction effects of the variables were taken into account and provided for the design recommendations.

Plant materials have been used in different fields such as therapeutics, cosmetics, and energy for ages. Several studies have investigated seeds, whether common or not, in order to ensure a better valuation of natural resources. Among these, Pistacia atlantica Desf. has been the subject of several works on its characterization and valorization. Among the current trends in sustainable development and environmental protection, valorizing natural wild plants via green chemistry has become prevalent. One of these plants, Pistacia atlantica Desf., is a tree that grows in arid and semi-arid areas, notably in Tunisia, and produces seeds rich in oil. In this study extracting the oil from its seeds is tried by three methods (supercritical carbon dioxide (CO2), pressure, and hexane), and the efficiency of these extraction processes is compared in order to obtain the best yield and maximize its valorization in a variety of industrial fields. The obtained oil is found to be rich in polyunsaturated fatty acids, namely linoleic and oleic acids, with a similar acidic composition among all extraction methods. The tocopherol composition of the oil is determined using high performance liquid chromatography. The total polyphenol content is determined using the Folin-Ciocalteu colorimetric analysis method. The results show that the seed oil of Pistacia atlantica Desf. extracted by supercritical CO2 gives the highest extraction yield (25%) and the lowest acidity and peroxide values with a high degree of oxidation at 232 and 270 nm. This method also gives the highest content of alpha, gamma, and delta tocopherol as well as total phenolic content compared to the other extraction methods. The composition of chlorophylls and carotenes in the seed oil of Pistacia atlantica Desf. is determined. Besides, the analysis of the sterol composition reveals that beta-sitosterol is still prevailing. Among all the tested extracts, the supercritical CO2 extract demonstrates the best antioxidant performance against the tested radicals. The oil extracted by supercritical carbon dioxide (CO2) is of a higher quality compared to that extracted by pressure and by hexane.