ali hajji

Institut Agronomique et Vétérinaire Hassan II, Industrie Agro Alimentaire, Faculty Member

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David Seamon

Kansas State University

Armando Marques-Guedes

UNL - New University of Lisbon

Sabyasachi Mishra

National Institute of Technology Rourkela

Gary Feinman

Field Museum

naveen noronha

Visvesvaraya Technological University

Iain Staffell

Imperial College London

Miguel Garí Pallicer

Universitat de les Illes Balears

Marc Mostade

University of Liege

A. Z. Hafez

University of Nottingham

Clémentine Stunault-Moncet

Université Toulouse II Jean Jaurès

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Papers by ali hajji

Theoretical and experimental investigation of a constant-pressure adsorption process

International Journal of Heat and Mass Transfer, Dec 1, 1995

This paper presents a theoretical and experimental analysis of a constant pressure adsorption pro... more This paper presents a theoretical and experimental analysis of a constant pressure adsorption process. The governing heat and mass transfer equations derived from local thermodynamic equilibrium and energy balance are solved numerically. The model is validated by comparison with experimental results. It is then used to analyze the effect of some operating and design parameters on a constant-pressure sorption process.

Dynamic Analysis of a Closed-Cycle Solar Adsorption Refrigerator Using Two Adsorbent-Adsorbate Pairs

Journal of Solar Energy Engineering, 1991

A dynamic analysis of a closed-cycle, solar adsorption refrigerator is presented. The instantaneo... more A dynamic analysis of a closed-cycle, solar adsorption refrigerator is presented. The instantaneous and daily system performance are studied using two adsorbent-adsorbate pairs, Zeolite 13X-Water and Chabazite-Methanol. The effect of design and operating parameters, including inert material thermal capacitance, matrix porosity, and evaporator and condenser temperatures on the solar and cycle coefficients of performance are evaluated.

Transient heat and mass transfer in film absorption of finite depth with nonhomogeneous boundary conditions

International Journal of Heat and Mass Transfer, 1992

A theoretical analysis of transient combined heat and mass transfer processes that occur m liquid... more A theoretical analysis of transient combined heat and mass transfer processes that occur m liquid desiccant film absorption is presented. Analytical expressions are derived for the tem~r~tturc and concentration in a stagnant film of finite depth. Comparison with experimental data allows the determination of the effective Lewis number. Using the analytical expressions, the transient variation of the heat and mass rates and the transient dependence of the dimensionless average temperature with Lewis number and the dimensionless enthalpy of absorption are presented.

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Improving the performance of adsorption heat exchangers using a finned structure

International Journal of Heat and Mass Transfer, 1996

This paper presents a numerical investigation of the sorption kinetics under constant-pressure co... more This paper presents a numerical investigation of the sorption kinetics under constant-pressure conditions using a finned adorption reactor. The governing equations, derived from local thermodynamic equilibrium and energy balance, are solved using an explicit scheme. The model is validated and used to analyze the effect of important design parameters on the performance of the adsorbent reactor. It is found that using metallic fins at sufficiently small intervals and reducing the contact resistance at the interface, metal-adsorbent can improve significantly sorption kinetics. However, the fin thickness and the nature of the metal have little effect on the rate of heat transfer. The model can be used to optimize the design of efficient adsorption heat exchangers.

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Analysis of combined fully-developed natural convection heat and mass transfer between two inclined parallel plates

International Journal of Heat and Mass Transfer, 1988

Abstract Fully-developed, combined, natural convection heat and mass transfer in an inclined open... more Abstract Fully-developed, combined, natural convection heat and mass transfer in an inclined open-ended channel is analyzed. General solutions to the governing equations are given and the conditions of existence of solutions are determined for all Lewis numbers. The results include expressions for the flow rate, Nusselt number and Sherwood number. Two examples illustrating the use of the general solutions are also presented.

Analysis of entropy production in a heat regenerator

International Communications in Heat and Mass Transfer, 1994

Abstract An anlytiical expression is derived for the rate of entropy production in a heat regener... more Abstract An anlytiical expression is derived for the rate of entropy production in a heat regenerator. It is then proved that this rate vanishes at the limit of an infinite heat transfer coefficient. For a finite transfer coefficient, the profile of the rate of entropy production has a bell-shape profile.

Dynamic simulation of a recuperative adsorption heat pump

Energy, 1993

ABSTRACT

Experimental and theoretical study of a constant-volume adsorption process

Energy, 1994

During the multi-square punch forming (MSPF) process of hull plate in shipbuilding industry, the ... more During the multi-square punch forming (MSPF) process of hull plate in shipbuilding industry, the springback occurs after unloading due to the elastic deformation energy stored in the plate, which makes the one-step forming difficult to achieve. This paper aims to uncover the physical mechanism of the elasto-plastic deformation and the springback characteristics in the MSPF process and derive appropriate mathematical interpretations. A series of strip-forming tests were carried out by using the three-dimensional computational numerical control (CNC) hull plate forming machine. Besides, by considering the follower load with moving boundary condition in the forming process, theoretical equations are derived to analyse the forming mechanism and springback characteristics of the strip, and their accuracy is demonstrated through the comparison with experimental data. Through the proposed formula, the strip's profile under different loadings in the forming process can be properly described, which provides the characteristic range of the strip (e.g. the strip's thickness) which can be formed on a specific MSPF machine. Parametric studies indicate that the springback ratio of the strip increases with the increase of the strip's thickness and the tool curvature.

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Thermodynamics of Constant-Pressure and Constant-Volume Sorption Processes in Closed-Cycle Soliddesiccant Systems

Chemical Engineering Communications, 1991

A relationship for adsorption equilibrium is proposed and compared to known potential theories. U... more

Methodology for Optimizing Sewage Sludge Treatment, Valorization and Disposal Methods. Application to the Marrakech (Morocco) Wastewater Treatment Plant

International Journal of Innovative Technology and Exploring Engineering, 2020

Wastewater treatment leads to a significant production of about 150 to 200 kg of sludge per popul... more Wastewater treatment leads to a significant production of about 150 to 200 kg of sludge per population equivalent (P.E) per year, with a humidity level higher than 90%. The treatment and discharge of this sludge involves high costs for wastewater treatment plants (WWTPs), which can amount to up to 60% of their total operating cost. The environmental and public health aspect should also be carefully considered during evacuation as sludge may contain harmful elements. Currently, several treatment, valorization and disposal methods are possible for sludge. In order to respect the various constraints on the possibilities of discharging sludge and to minimize its cost, a reasonable approach must be followed to establish an optimal management path according to the WWTP situation. The objective of this work is to develop a methodology for optimizing sludge treatment, valorization and disposal methods for a given WWTP. This method is based on operational research technique. The methodology ...

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Optimal design of an off-grid hybrid solar photovoltaic-diesel system in community electrification of a fishing village in Morocco

2016 International Renewable and Sustainable Energy Conference (IRSEC), 2016

In the present work, we developed a computerized methodology to optimize the design of an off-gri... more In the present work, we developed a computerized methodology to optimize the design of an off-grid hybrid solar community electrification. It is based on a 3-phase process: (1) Determining the load profile of the village by making a power balance, the average daily consumption and establishing the load; (2) Determining the optimum photovoltaic (PV) peak capacity and storage capacity which yield the lowest total specific discounted costs over a specified project lifetime; and (3) Sizing all PV system components and updating the cost-benefit analysis based on quoted project cost. This methodology is applied to Aftissat, a fishing village in Boujdour (Southern Morocco). We found an optimal peak capacity of 128 kWp, and 623 kWh of battery storage capacity. The 126 kWp PV capacity, and 800 kWh battery storage capacity were actually installed. The payback period is 9.0 years, and the discounted specific cost is 1.40 MAD/kWh. The corresponding CO2 emissions are reduced by 98.3%. Laayoune is one of the most interesting solar locations with a potential of 2 450 kWh m−2 year−1 at an optimum angle of the panels of 28°. An increase in diesel rate and solar irradiation of the site greatly reduces the PV power and storage capacity to install. The depth range of ideal discharge is between 40 and 70%. Storage batteries with a liquid electrolyte tubular plate technology provide the lowest specific cost (1.1 MAD/kWh).

Design and Cost Optimization of Small-Scale PV-Powered Reverse Osmosis Desalination (Case Study)

Photovoltaic-powered reverse osmosis (PVRO) desalination can potentially be the solution to two m... more Photovoltaic-powered reverse osmosis (PVRO) desalination can potentially be the solution to two major global issues: water and energy. This technique not only increases water supply but also decreases the dependency on fossil fuels. The objective of the present paper deals with the design of a small-scale (20 m3/day) PVRO desalination unit, given the daily water needs, in addition to conducting an economic analysis to determine both the total investment and the specific desalination cost (MAD/m3). For this case study in Dakhla (South of Morocco) which supplies drinking water for a coastal hotel, the system configuration that has the lowest investment and specific water costs is the one with an energy recovery system and separate components. The specific energy consumption of such system was found to be 2.92 kWh/m3. The total costs over a 10-year period for this system is 1,056,024 MAD, producing water at a cost of 15.47 MAD/m3. An effective methodology is used for determining the optimal design configuration for a PVRO desalination station. For our case study, the results show two optimal solutions, both of which operate with one machine only. The first one, which yields the lowest initial investment (828,000 MAD), consists of installing one RO machine with a nominal capacity of 36 m3/day, 23 kWp of PV power and 50.5 kWh of battery storage. The second optimal combination, which generates the lowest cost of water during 10 years (14.28 MAD/m3), consists of installing one bigger RO machine having a capacity of 72 m3/day, 32 kWp of PV power and 38.5 kWh of battery storage.

Analyse technico-économique et évaluation de l’impact environnemental de la cuisson solaire directe au Maroc

L’objectif de cet article est de presenter une methodologie de dimensionnement des cuiseurs solai... more L’objectif de cet article est de presenter une methodologie de dimensionnement des cuiseurs solaires directs, faire l’analyse economique et evaluer l’impact environnemental de la cuisson solaire directe au Maroc. Pour satisfaire les besoins energetiques d’un menage de 5 personnes consommant 3 kg de repas a midi pour une duree de cuisson de 2,5 heures, un concentrateur parabolique de 1,4 m de diametre (surface utile de 1,6 m²) est necessaire. A l’echelle du menage, l’analyse financiere a revele que le temps de retour d’un cuiseur solaire direct par rapport au butane varie de 4 a 10 annees selon le taux de la subvention publique. Par rapport au bois de feu, le temps de retour varie de 0,6 a 10 annees selon le rendement du four et le prix du bois. A l’echelle nationale, pour subventionner a hauteur de 50% les cuiseurs solaires directs avec un taux de penetration de 50% en milieu rural, l’Etat doit consentir un budget de 1,61 milliard de dirhams (1$US=10 Dirhams). Cet investissement per...

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Modeling, testing, and parametric analysis of a parabolic solar cooking system with heat storage for indoor cooking

Energy, Sustainability and Society, 2017

Background: In an ever-changing world where needs increase daily due to economic growth and demog... more Background: In an ever-changing world where needs increase daily due to economic growth and demographic progression, where prices are unstable, where reserves are running out, where climate change is topical, the energy issues are increasingly marked by the question of sustainability. In many developing countries, wood and subsidized butane are the main sources of energy used for cooking in households. The use of solar energy in domestic cooking becomes unavoidable. Several models of solar cookers have been proposed, but most of them dealt with box and oven types of solar cookers without storage. Methods: This paper presents a dynamic thermodynamic model of a parabolic solar cooking system (PSCS) with heat storage, along with a comparison of the model solution with experimental measurements. The model uses various thermal resistances to take into account heat transfer between the different parts of the system. Results: The first experimental setup consists of a parabolic concentrator (0.80-m diameter and 0.08-m depth) and a 1.57-l cylindrical receiver. The second experimental setup is composed of a parabolic concentrator (1.40-m diameter and 0.16-m depth), the same receiver, and a 6.64-l heat storage. Tests were carried out in Rabat, Morocco, between April 24 and July 10, 2014, and between May 15 and June 18, 2015. Synthetic oil is used as a transfer fluid and a sensible heat storage. Conclusions: Comparison between predicted and measured temperatures shows a good agreement with a relative error of ± 4.4%. The effects of important system design and operating parameters were also analyzed. The results show that a 50 W m −2 increase of the daily maximum solar radiation increases the storage temperature by 4°C and a 5% increase of the receiver reflectance or absorptance improves the maximum storage temperature by 3.6 and 3. 9°C, respectively. Optimizing the aspect ratio of the receiver to 2 gives a maximum storage temperature of 85°C. Increasing the thermal fluid mass flow rate from 0 to 18 kg h −1 , or the receiver thermal insulation from 0.01 to 0. 08 m, increases the maximum storage temperature by 65 and 17°C, respectively.

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Optimal design, field performance and impact of energy legislation on the cost effectiveness of a domestic on-grid photovoltaic system in Morocco

2015 3rd International Renewable and Sustainable Energy Conference (IRSEC), 2015

Solar PV is an important part of the Moroccan national energy strategy which helped the recent de... more Solar PV is an important part of the Moroccan national energy strategy which helped the recent development of this sector. In the present work, we developed a computerized methodology to optimize the design of on-grid solar PV systems which is adapted to local power billing, feeding restrictions and legislation in Morocco. It is based on a 3-phase process: (1) Determining the customer's power load profile using his monthly electric bills and the "typical load curve" developed by the national power utility company (ONEE); (2) Determining the optimal PV peak capacity which yields minimum total updated costs over a specified project lifetime; and (3) Sizing all PV system components and updating the cost-benefit analysis based on quoted project cost. This methodology is applied to a household in Rabat (34° 00' N, 6° 50' W). We found an optimal power of 2.1 kWp and a payback period between 7 and 13.2 years. The system was installed and its performance monitored for more than two years. The results show that power production and energy cost savings are close to the design values. The household energy consumption/cost and its corresponding CO2 emissions are reduced on average by 56%. The impact of energy policy can affect the cost effectiveness and the competiveness of economic operators.

Performance Testing of a Parabolic Solar Concentrator for Solar Cooking

Journal of Solar Energy Engineering, 2016

The objective of the present work is to conduct a worthwhile experimental study of the performanc... more The objective of the present work is to conduct a worthwhile experimental study of the performance of a parabolic solar concentrator for solar cooking. The literature survey briefly highlights the standard performance tests of solar cookers and gives the experimental studies obtained by some authors. Our experimental device, made from simple means using local materials, consists of a parabolic concentrator having a 0.80 m diameter and 0.08 m depth as well as a cylindrical absorber with a 0.10 m diameter and is 0.20 m long. The testing period started on April 24th, 2014 and continued till July 10th of the same year, in Rabat (33°53′ N, 6°59′ W), Morocco. The average ambient temperature is 24 °C. The results show that using synthetic oil as the heat transfer medium has achieved a maximum temperature of 153 °C against 97 °C with water. The overall heat loss coefficient is estimated to be 17.6 W m−2 °C−1. The energy and exergy efficiencies are, respectively, 29.0–2.4% and 0.1–0.5%. Add...

Solar heating system for a Hammam. Design and implementation of a public bath in El Attaouia (Morocco)

Analysis of combined heat and mass transfer in closed-cycle adsorption cooling systems

A relationship for the solid-vapor adsorption equilibrium is proposed and proved to represent acc... more A relationship for the solid-vapor adsorption equilibrium is proposed and proved to represent accurately the experimental data and to be convenient for numerical calculations. Formulas describing the process involved in closed-cycle cooling and heating systems are also derived. These formulas are first applied in a dynamic analysis of a closed-cycle solar adsorption refrigerator. A computer program was written to study the effect of the design parameters and operating conditions on the system performance. A second application concerns the simulation of the regenerative adsorption cooling systems which were recently introduced to increase the performance of adsorption machines. A computer program was developed to analyze the dynamic behavior of such systems. An analytical investigation of the vapor-liquid absorption is presented. Closed-form solution were obtained where the depth of the absorbing solution is taken into account. The effect of interfacial instability on heat and mass t...

A Methodology to Evaluate the Potential of Using PVRO Desalinated Brackish Water in Irrigation on Large Farming Scale: Application to Saline Area in Rhamna Province (Morocco)

Technologie de séchage solaire des boues des stations d’épuration des eaux usées et son impact sur la gestion des boues au Maroc

Revue Marocaine des Sciences Agronomiques et Vétérinaires, 2020

Résumé La gestion des boues est un problème majeur dans les stations d’épuration des eaux usées (... more Résumé La gestion des boues est un problème majeur dans les stations d’épuration des eaux usées (STEP), son coût peut aller jusqu’à 60% du coût d’exploitation de ces dernières. L’objectif de ce travail est de faire le point sur le séchage solaire de ces boues au niveau mondial et ensuite analyser son impact sur la gestion des boues au Maroc. Le séchage solaire des boues se fait dans des serres pouvant être ouvertes, fermées ou chauffées. La performance d’une serre est évaluée par sa capacité évaporatoire (CE). La CE varie de 2,2 à 12 kg d’eau évaporée par m2 et par jour selon le climat du site d’installation, la saison de l’année et le type de technologie installée. La CE constitue aussi le paramètre majeur du dimensionnement des serres de séchage solaire. L’utilisation de l’énergie solaire permet de diminuer le coût d’exploitation par rapport au séchage conventionnel. Le coût d’investissement varie de 250 à 500 €/m2 et le coût d’exploitation de 20 à 250 €/tonne de matière sèche (MS...

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Theoretical and experimental investigation of a constant-pressure adsorption process

International Journal of Heat and Mass Transfer, Dec 1, 1995

Dynamic Analysis of a Closed-Cycle Solar Adsorption Refrigerator Using Two Adsorbent-Adsorbate Pairs

Journal of Solar Energy Engineering, 1991

Transient heat and mass transfer in film absorption of finite depth with nonhomogeneous boundary conditions

International Journal of Heat and Mass Transfer, 1992

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Improving the performance of adsorption heat exchangers using a finned structure

International Journal of Heat and Mass Transfer, 1996

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Analysis of combined fully-developed natural convection heat and mass transfer between two inclined parallel plates

International Journal of Heat and Mass Transfer, 1988

Analysis of entropy production in a heat regenerator

International Communications in Heat and Mass Transfer, 1994

Dynamic simulation of a recuperative adsorption heat pump

Energy, 1993

ABSTRACT

Experimental and theoretical study of a constant-volume adsorption process

Energy, 1994

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Thermodynamics of Constant-Pressure and Constant-Volume Sorption Processes in Closed-Cycle Soliddesiccant Systems

Chemical Engineering Communications, 1991

A relationship for adsorption equilibrium is proposed and compared to known potential theories. U... more

Methodology for Optimizing Sewage Sludge Treatment, Valorization and Disposal Methods. Application to the Marrakech (Morocco) Wastewater Treatment Plant

International Journal of Innovative Technology and Exploring Engineering, 2020

Download

Optimal design of an off-grid hybrid solar photovoltaic-diesel system in community electrification of a fishing village in Morocco

2016 International Renewable and Sustainable Energy Conference (IRSEC), 2016

Design and Cost Optimization of Small-Scale PV-Powered Reverse Osmosis Desalination (Case Study)

Analyse technico-économique et évaluation de l’impact environnemental de la cuisson solaire directe au Maroc

Download

Modeling, testing, and parametric analysis of a parabolic solar cooking system with heat storage for indoor cooking

Energy, Sustainability and Society, 2017

Download

Optimal design, field performance and impact of energy legislation on the cost effectiveness of a domestic on-grid photovoltaic system in Morocco

2015 3rd International Renewable and Sustainable Energy Conference (IRSEC), 2015

Performance Testing of a Parabolic Solar Concentrator for Solar Cooking

Journal of Solar Energy Engineering, 2016

Solar heating system for a Hammam. Design and implementation of a public bath in El Attaouia (Morocco)

Analysis of combined heat and mass transfer in closed-cycle adsorption cooling systems

A Methodology to Evaluate the Potential of Using PVRO Desalinated Brackish Water in Irrigation on Large Farming Scale: Application to Saline Area in Rhamna Province (Morocco)

Technologie de séchage solaire des boues des stations d’épuration des eaux usées et son impact sur la gestion des boues au Maroc

Revue Marocaine des Sciences Agronomiques et Vétérinaires, 2020

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