Y. Zeraouli

• Université de Pau et des Pays de l'Adour

This study aims to investigate the storage of heat from a heat pump's condenser in a well-insulated cylindrical tank filled with spherical capsules containing a phase-change material (PCM). Using a detailed physical model and the enthalpic method, the system's operation and phase change phenomena are simulated. The impact of various operational par...

Green hydrogen potential as a clean energy carrier presents promising prospects in the fight against climate change. The most efficient method of producing decarbonized hydrogen is through electrolysis, which involves splitting water molecules using renewable sources of electricity. Morocco boasts various advantages that enable it to play a pivotal...

This paper presents a physical model to study the energy efficiency of a residential refrigerator containing multiple phase change materials (PCMs). This model was validated using experimental data from published literature. The impact of varying parameters, such as PCM thickness (from 3 up to 7 mm), internal load (from 0 up to 20 W) and external t...

In this work, a novel detailed dynamic model for latent cold thermal storage unit containing water as phase change material (PCM) is presented. The proposed dynamic model is based on transient energy balances for both PCM capsules and heat transfer fluid (HTF). The apparent heat capacity approach is used to model phase transition processes in PCM,...

Nowadays, several countries have adopted an energy transition policy to achieve carbon targets and decarbonize transport while improving their electricity mixes. Electric vehicles are ubiquitous, considering its role in the energy transition as a promising technology for large-scale storage of intermittent power generated from renewable energy sour...

The cold chain represents a sensitive component that directly affects the food safety of our society. Refrigerated transport is one of the riskiest steps that could break it. During transportation, the control of internal temperature and delivery times is essential to preserve and improve the quality and shelf life of foodstuffs, and to reduce thei...

Refrigerated transport has been of interest to the scientific and industrial community for centuries. So far, temperature fluctuations during loading/unloading have been a major challenge. It is therefore essential to develop solutions to ensure the quality and safety of transported foodstuffs against temperature fluctuations as well as to reduce e...

Solar photovoltaic thermal (PV/T) systems have the capacity to become a key actor in the world's energy transition. The design of such systems requires the implementation and development of physical models, which can predict their thermal and electrical performances. In this paper, some of the main models for designing PV/T systems are developed. I...

In this work, a comprehensive numerical study on a latent heat storage system is presented. The adopted storage system consists of a tank with a fixed bed of phase-change materials (PCMs). A numerical model simulating the dynamic and thermal behaviour of this system during the discharge period has been developed and validated using experimental dat...

The cold chain represents a sensitive element that directly affects the food security of our society. Refrigerated truck transport directly affects the quality and shelf life of perishable products according to their appropriate temperature ranges, which are key elements of the chain. In this context, it is important to examine the cooling mechanis...

In the recent decade, Machine Learning techniques have been widely deployed in solar systems due their high accuracy in predicting the performances without going through the physical modelling. In this work, the Artificial Neural Network (ANN) method is adopted to forecast the electrical and thermal efficiencies of a photovoltaic/thermal (PVT) air...

Given the abundance of solar irradiation in Africa, different types of Solar Water Heating technologies can offer practical and reasonable solutions that are valuable for African people and their environment. However, these technologies' impacts were not quantified, and lack of studies could be in part attributed to the weak implementation of solar...

The objective of this work is to a physical model to describe the thermal performance of cylindrical tank filled with spherical water capsules during the storage period. A particularity is encountered in this type of storage; it refers to the supercooling phenomenon caused by the delay in the crystallization of the water in the capsules. The origin...

In recent years, a number of Photovoltaic/Thermal (PV/T) air designs were tested and investigated. However, it is challenging to assess whether a sophisticated design will be significantly more efficient than a basic one. This paper intends to outline different investigations conducted over the last years on photovoltaic-thermal technology. Finding...

This paper investigates the energetic performance of solar air-conditioning by absorption chiller applied for building sector in Morocco. The combined effects of cooling profiles (Morning, Day and Morning), building categories (residential house, building office and hotel) and collector’s technology on the potential of solar cooling installation op...

In this research, heat transfer in a construction material integrating microencapsulated phase change material (PCM) has been studied and analyzed using a physical model based on the apparent heat capacity approach. The PCM considered includes impurities and behaves like a binary solution. The physical model was validated with the experimental and...

An axisymmetric physical model based on the porous medium approach was performed to quantify the thermal gradients inside a building material containing microencapsulated phase change material (PCM) in the differential scanning calorimeter cells. The conservation equations are solved numerically using finite difference method. The general expressio...

This paper focuses on the potential of a solar installation combining airconditioning , heating and Domestic Hot Water (DHW) production processes intended for mass use in building sector in Morocco. The objective is to measure the relevance of the investment in such systems through a technico-economic assessment and a risk analysis based on classic...

In this paper, the thermal behavior of a micro-encapsulated phase change material wallboard is numerically investigated. A physical model coupling the heat transfer inside the wallboard with the heat transfer and the phase change process within micro-encapsulated phase change material (PCM) is introduced. The effect of different parameters such as...

This paper aims to simulate heat generation in two devices, namely the horizontal thermal storage tank and the circulation pipe, which are considered as the main devices constituting solar water heating systems. For this purpose, two dimensional simulations were performed, so as to numerically investigate the proposed configurations. The storage ta...

In this paper, a comprehensive computational fluid dynamics (CFD) modeling was built to reproduce the pool boiling in the evaporator section and the liquid film condensation in a closed thermosyphon. The two phase Volume Of Fluids (VOF) model was used to simulate the heat transfer during evaporation and condensation inside a closed thermosyphon. Th...

This paper investigates the influence of the domestic hot water load profiles and the collector's technology (Flat Plate FPC, Evacuated Tube ETC and Compound Parabolic CPC) on the performance of forced circulation solar water heaters operating under various climatic conditions. For this end, a typical single family house composed of five occupants...

The aim of this work is to investigate the energetic performance of a solar cooling system using absorption technology under Moroccan climate. The solar fraction and the coefficient of performance of the solar cooling system were evaluated for various climatic conditions. It is found that the system operating in Errachidia shows the best average an...

Satisfying energy requirements in its most suitable form is the great challenge of the world in the 21st century. Moroccan authorities are fully aware about this challenge, especially with the population and economic growth that causes a sharp increase of energy demand. This paper presents the renewable energy potentials and the national strategy c...

The building sector is considered as the biggest single contributor to world energy consumption and greenhouse gas emissions. Therefore, a good understanding of the nature and structure of energy use in buildings is crucial for establishing the adequate future energy and climate change policies. Availability of the updated data is becoming increasi...

This paper presents a review of the available technologies to provide cooling from solar energy for both thermal and photovoltaic ways. Several multi-criteria performance indicators figuring in the literature are presented followed by a pros and cons analysis of the different solar thermal cooling processes. A market study is also carried out to ev...

In this paper, we reported the current status of the energy sector and its future challenges in Morocco. Recent strategies deployed by the government for sustainable development were reviewed and discussed. These strategies put the transition to renewable alternatives on the top of the national policy implications for energy security and low-carbon...

The aim of this study is to assess the technical feasibility of solar water heaters (SWH) under Moroccan conditions. Annual simulations in six different regions for two technologies: flat plate and evacuated tube collectors were carried out using TRANSOL program. It is found that high values of solar fraction can be reached in almost the studied re...

This article suggests a detailed comparison of 7 working pairs intended for use in solar adsorption cooling systems. The performance analysis was based on two indicators: adsorption capacity and solar coefficient of performance. Based on a reformed form of the Dubinin-Astakhov equation, a 3D graph was constructed to show the adsorbate concentration...

In this paper, we introduce a dynamic model of a thermal adsorber powered by solar energy. The system operates with silica gel (as an adsorbent) and water (as a refrigerant). The Finite Difference approximation was used; the obtained numerical model was then incorporated in a MATLAB code in order to solve the system of algebraic equations modeling...

In this paper, a physical model is built to study the eutectic and progressive melting of salt solution in DSC (Differential Scanning Calorimetry) cells. The finite volume method is utilized to solve the heat transfer problem, and the general implicit source-based enthalpy method is employed to handle the absorbed latent heat during the phase chang...

In this paper, an updated review of the state of technology and installations of several energy storage technologies were presented, and their various characteristics were analyzed. The analyses included their storage properties, current state in the industry and feasibility for future installation. The paper includes also the main characteristics...

The heat transfer characteristics during melting of the (phase change material) PCM dispersed inside an emulsion are investigated theoretically and experimentally by using (differential scanning calorimeter) DSC. Genetic algorithm is used to determine the unknown parameters in the physical model. The dispersed PCMs are hexadecane, heptadecane and o...

The application of phase change materials (PCMs) for building applications has received considerable attention in recent years due to the large storage capacity and isothermal nature of the storage process. This paper summarizes the results of a physical model and analysis of thermal energy storage and temperature control achieved using mortar inco...

In this paper a physical model is built to investigate the non-isothermal freezing kinetic in ice slurry systems. The global Nakamura-type kinetics is adopted to describe the nucleation rate during the freezing process. A genetic algorithm is used to determine the nucleation probability of ice slurry. The finite difference method is utilized to sol...

A main purpose of using binary solutions as phase change materials is to benefit from the latent heat or enthalpy difference at melting. In the design of latent heat storage systems, the enthalpy change of the PCM has to be known with high precision. In this article, we show with the help of experimental data and numerical analysis why the use of d...

Heat transfer characteristic during crystallization of the phase change material (PCM) dispersed inside an emulsion is investigated theoretically and experimentally by using Differential Scanning Calorimeter (DSC) technique. The dispersed PCMs are hexadecane, octadecane and water. Nucleation laws are used to simulate the supercooling phenomenon. Th...

Dans ce travail, nous nous intéressons à l'utilisation de la calorimétrie différentielle à balayage (DSC) dans la détermination de la capacité thermique massique apparente et de l'enthalpie de solutions binaires aqueuses présentant un eutectique. Nous décrirons les phénomènes en relation avec le processus de fusions eutectique et progressive de ces...

A two-dimensional numerical model has been developed to investigate the phase-change of ice near 4 °C in a rectangular cavity. The enthalpyporosity model is reformulated in terms of conservation equations of mass, momentum and heat to account for the evolution the solid/liquid interface. Constant and time-dependent (with sinusoidal law) temperature...

Heat transfer characteristics during crystallization and melting of the phase change material (PCM) dispersed inside an emulsion are investigated theoretically and experimentally. The dispersed PCMs are hexadecane, octadecane and water. The crystallization and melting processes are not symmetrical because of the supercooling phenomenon induced by t...

a b s t r a c t Differential scanning calorimetry (DSC) and numerical simulations have been used to determine some kinetics parameters of phase change materials (PCM). The heating rate affects the development of the DSC thermograms and also the apparent specific heat capacity of the PCM during the phase change process. PCM geometry has also a defin...

The interaction between laminar Rayleigh–Benard convection and non-isothermal melting process is studied for the case of ice slurry kept in a rectangular cavity heated from the bottom. Clear visualization of the Rayleigh–Benard convective cells and their interaction with the melting front are obtained. It is observed that the convective cells are c...

Melting of the binary mixture system of tetradecane and hexadecane in Differential Scanning Calorimetry (DSC) cell has been investigated experimentally and numerically. Different concentrations of tetradecane–hexadecane paraffin mixture were studied. It is found that the phase change process of the binary mixture takes place over a temperature rang...

a b s t r a c t This study addresses the heat transfer in differential scanning calorimetry (DSC) cells during the melting process of an eutectic solution. The energy and entropy equations for two-dimensional transient ther-mal analysis with associated boundary and initial conditions are solved numerically using a fixed grid numerical model with th...

A physical model for laminar forced-convection heat transfer of microencapsulated phase-change-material suspension in a circular tube with constant heat flux has been presented in this paper. Suspensions of aqueous solution and water microcapsules are tested. The energy equation is formulated by taking into consideration the heat absorption due to...

In this study, heat transfer for ice slurry flows was investigated. For the experiments, ice slurry was made from 9% ethanol–water solution flow in a 20 mm internal diameter, 1000 mm long horizontal copper tube. The ice slurry was heated by a cylindrical electrical resistance. Experiments of the melting process were conducted with changing the ice...

A model has been developed for the simulation of laminar hydrodynamic and heat transfer characteristics in a horizontal circular tube for a suspension flow with micro-size phase-change material (PCM) particles. The energy equation is formulated by taking into consideration the heat absorption (or release) due to the phase-change process. The heat s...

A new technique to improve the accuracy of the Differential Scanning Calorimeter (DSC) for the measurement of the specific heat capacity has been proposed. This technique is based on the use of multiple heating rates DSC. The effect of the heating rate and the sample mass on the heat capacity measurement is also discussed. Heat capacities of variou...

This paper presents some results obtained by Differential Scanning Calorimetry (DSC) for characterizing the phase transition within an emulsion. The dispersed substances are either hexadecane, octadecane, water or binary solution. A non-equilibrium model taking into account the inter-phase heat transfer between the emulsifying medium and the dispe...

Compared with classical secondary refrigerant loops that continuously supply cold energy, ice-slurry systems rely on the use of storage tanks designed to store and supply the cold energy on demand; thus cutting off cooling peak demands. To reliably operate an ice-slurry cooling system, it is very important to know the ice-loading fraction within th...

In this research, based on the work of Jamil et al. [A. Jamil, T. Kousksou, Y. Zeraouli, J.P. Dumas, E. Schall, Isothermal and non-isothermal melting of the binary solution inside an emulsion. Thermochim. Acta 460 (2007) 22–27], an experimental method and numerical simulations were developed to determine the liquidus temperatures of the dispersed b...

The object of this paper is-to present a simple model for the latent storage systems by using a phase-change material encapsulated in the spherical capsules. When designing phase-change-material systems, it is important to minimize thermal irreversibilities, because it works best when irreversibilities are done. In this paper, second law analysis i...

The measurements of solid–liquid phase diagrams for a binary mixture using a differential scanning calorimeter are revisited in this paper. A new method employing the DSC curves and a theoretical model to detect solid–liquid equilibrium temperature of the initial mixture before freezing is proposed. The liquidus temperatures for different compositi...

The aim of the present paper is to study the melting process inside an emulsion using the non-equilibrium model of microscopic heat transfer between the emulsifying medium and the dispersed droplet of binary solution (DSC). DSC experiments are used to validate the numerical results. The effects of the heating rate, mass fraction of the dispersed sa...

Il s'agit d'un travail expérimental mené sur un banc d'essais hydrauliques où circule un mélange de glace et d'une solution d'éthanol. Les mesures simultanées des températures et des concentrations de la phase liquide, à l'entrée et à la sortie d'un échangeur, simulant le déstockage, ont révélé l'existence d'un déséquilibre thermodynamique entre le...

Differential scanning calorimetry (DSC) is applied to analyse the process of ice melting. Experimental results were compared to those obtained by a numerical simulation in which a conventional enthalpy formulation was applied. The effects of various parameters on the kinetics of transformations and therefore the shape of curves has been analysed an...

We present in this paper a new method of determining the nucleation probability J(T) of a supercooled liquid dispersed within an emulsion, based on the analysis of the thermogram obtained during a regular cooling. The thermal behaviour of the sample during the cooling is modelled in order to calculate the thermogram and so to compare it with the ex...

In order to understand the non-isothermal melting kinetics in the ice slurry, a differential scanning calorimetry (DSC) was used. Experimental results were compared to those obtained by a numerical simulation in which a general enthalpy method was applied. In this work the ice slurry studied consists of ice particles uniformly dispersed within a wa...

The main objective of this paper is to present a model for the heat transfer in the case of the melting of saline binary solution. This model is applied to calorimetry in order to determine the kinetics of the eutectic melting. The investigated cell containing the solution is a cylinder of a few mm3 in volume. By simulation, we could replicate the...

Parmi les différentes possibilités existantes de conversion de l'énergie solaire en électricité, les machines à "air chaud" fonctionnant à température moyenne semblent très prometteuses, en particulier pour les faibles puissances (< 50 kW électrique). Le couplage d'un concentrateur solaire cylindro-parabolique avec une machine à cycle de Joule (i e...

In this paper, we propose a model concerning the thermal transfers inside an emulsion of aqueous saline binary solution during the crystallization of the dispersed undercooled droplets. This model takes into account the erratic character owed to the probability of water crystallization, and to the probability of salt apparition. It also takes into...

Heat transfer models during the melting of a dispersed binary solution. In this paper, we present a model for heat transfers occurring during the melting of crystallized droplets of a binary solution dispersed within an oil. This model takes into account the heat conduction within the emulsion associated with a heat source (sink) due to the eutecti...

In this paper, we present a model for heat transfers occurring during the melting of crystallized droplets of a binary solution dispersed within an oil. This model takes into account the heat conduction within the emulsion associated with a heat source (sink) due to the eutectic melting of droplets followed by the progressive melting. The model has...

Results concerning the crystallization of a hot melt adhesive are presented. This adhesive was a liquid at high temperature (160°C) and was deposited on a wood slab kept at ambient temperature. Cooling can be enhanced by circulating air above the adhesive. The temperature within the adhesive and the wood were measured versus time under three condit...

A general study of the heat transfers inside the cell of a differential scanning calorimeter is presented. In Part 1 of this study, the crystallization of undercooled droplets of an emulsion is analysed. It is demonstrated that the classical assumption of a uniform temperature in the cell cannot explain the shape of the thermogram. The model, which...

A model is presented to explain the shape of the thermogram obtained by differential scanning calorimetry of the melting of the crystallized droplets of an emulsion. This model is entirely different from the model presented in Part 1 of this study concerning the crystallization of undercooled liquid droplets. In spite of the purity of the dispersed...

Experiments on heat transfers inside an emulsion when the dispersed phase crystallizes or melts have previously been presented [Dumas et al., Eurotherm Seminar 5 (1988)]. The crystallization and melting processes are not symmetrical because of the large undercooling induced by the smallness of the emulsion droplet sizes. The space-time evolution of...

The heat transfers during the melting of the crystallized droplets inside an emulsion are investigated. Contrary to the crystallization case (see Part 1), in the case of pure substances, the melting of the crystallized droplets occurs, upon heating, at a fixed temperature which corresponds to the phase equilibrium and the kinetics of melting depend...

Ice slurry flows have been receiving considerable attention because of their usefulness for transportation of ice and cold. One of the main components of a closed ice slurry system is the heat exchanger in which ice slurry absorbs heat resulting in the melting ice crystals. A detailed knowledge of heat transfer and pressure losses inside the heat e...