Ibrahim I. El-Sharkawy

• Ph.D.
• Professor (Full) at University of Sharjah

The search for potable water for quenching global thirst remains a pressing concern throughout many regions of the world. The demand for new and sustainable sources and the associated technologies for producing fresh water are intrinsically linked to the solving of potable water availability and hitherto, innovative and energy efficient desalinatio...

This paper presents the state-of-the-art of the integration of adsorption chillers into different configurations of combined cooling, heating, and power (CCHP) systems. Adsorption chillers, as a thermally-activated cooling system, provide a great solution to the utilization of low-temperature waste heat, thus help to increase the efficiency of the...

This paper thoroughly reviews the integration of absorption, adsorption and desiccant cooling technologies into vapor compression cooling/refrigeration systems. Different configurations of hybrid absorption-compression cooling systems have been collectively listed and studied based on energetic, exergetic, economic and environmental analysis. Sever...

Nowadays, atmospheric water harvesting (AWH) attracts great attention due to its potential to address water scarcity, especially in arid regions. A key component of adsorption-based atmospheric water harvesting is the adsorbent materials, which are porous materials characterized by high surface area and the ability to adsorb water vapor from the at...

In this study, thermal analysis of a vacuum-based bifacial solar thermal collector is conducted. This solar collector is expected to capture the solar radiation from both front and rear sides. One advantage of this collector is that it can work effectively in restricted positions where it should be installed in different positions such as verticall...

In this study, transient modelling for a solar-powered adsorption-based multi-generation system working under the climatic conditions of the Gulf Cooperation Council (GCC) countries is conducted. Three cities are selected for this study: Sharjah in the United Arab Emirates, Riyadh in Saudi Arabia, and Kuwait City in Kuwait. The system comprises (i)...

Despite all of the advantages of Photovoltaic (PV) systems, PV cells can only convert a small fraction of the solar spectrum into electricity due to the bandgap of the semiconductor material, which limits the converted photon energy. The remainder of the photon energy is dissipated as heat, leading to a rise in PV cell temperature, which lowers its...

The spectral-splitting technique splits the sun's spectrum into two pieces to save photovoltaic cells from overheating. The first component is instantly converted into electricity, while the second is used to generate heat energy. Since nanofluid simultaneously serves as a heat transfer liquid and a spectrum splitter, several investigations have de...

To avoid photovoltaic cells' overheating and to reduce their performance, the solar spectrum can be separated into two portions using the spectral splitting process. The first part is immediately transformed into electricity, while the second is used to produce heat energy. The system described in this paper combines a compound parabolic concentrat...

Spectral splitting technology can prevent a photovoltaic cell (PV) overheating ability and efficiency loss. The solar spectrum is split into two portions using this technology: the first produces electricity, while the second generates heat. The present research offers the design and performance evaluation of a novel PV-thermal (PV/T) system based...

The electricity sector has been undergoing profound transformations. In particular, the Portuguese self-consumer regime has allowed customers of the medium and low voltage electricity grid to be producers/consumers of electricity, actively contributing to greater energy efficiency. In this context, the energy that comes from the sun is not used to...

In this paper, the performance of innovative combined absorption and adsorption cooling (ABC-ADC) systems employing the same evaporating and condensing units is theoretically investigated. The generator of the absorption cooling (ABC) system is connected directly to the heat source system, and the outlet hot water is used to drive the desorber bed...

In this paper, thermal energy storage is utilized to store heat from solar energy and also use waste heat to counterbalance the demand and supply of energy. A laboratory multistage closed sorption thermal energy storage (STES) unit is designed and tested to study the performance of a cascade sorption system. The experimental unit consists of three...

In the present study, a theoretical assessment of an adsorption-assisted cascade compression refrigeration system powered by photovoltaic/thermal collectors is performed. The proposed system is intended to produce refrigeration and electricity simultaneously. Herein, mathematical modeling of the proposed system is developed using MATLAB/SIMULINK an...

In the present study, a theoretical assessment of an adsorption-assisted cascade compression refrigeration system powered by photovoltaic/thermal collectors is performed. The proposed system is intended to produce refrigeration and electricity simultaneously. Herein, mathematical modeling of the proposed system is developed using MATLAB/SIMULINK an...

Thermal energy storage (TES) systems are used to overcome daytime solar energy instability and fluctuation. Thermochemical TES systems are more promising than sensible and latent TES systems, particularly for solar energy applications with low and medium temperatures. The most recent literature reviews summarized the advancement of sorption energy...

This paper investigates microwave drying effect as a pretreatment method on the kinetic parameters of four torrefied biomasses. The considered biomasses are rice straw, rice husk, sugarcane, and cotton stalks. Dried samples (microwave or oven-dried) were then torrefied under isothermal conditions in a thermogravimetric analyzer (TGA) at two differe...

In this paper, a theoretical investigation of a solar-powered adsorption-based trigeneration system under the climate conditions of Alexandria, Egypt has been performed. The system is intended to provide the required cooling, electricity and domestic hot water (DHW) loads for a building in Alexandria throughout the year. The system comprises commer...

Desiccant dehumidification systems are thermally regenerated systems that can be used either as standalone or as complementary additives for conventional cooling systems. One of their best competitive qualities is the potential to utilize low-grade heat sources for the regeneration process, thus decreasing electrical power consumption and scaling b...

There are no data in the literature on the energy valorization of globe artichoke (GA) leaves. Thus, an extensive lab-scale experimental torrefaction, carbonization, and coking study was performed. Operative temperatures of 200 °C–1000 °C with 30–120 min residence times were considered. Nonisothermal thermogravimetric analysis was performed at 10,...

The performance of the mechanical vapor compression desalination system is limited due to the required vacuum pressure and associated high temperature scaling problem. Thus, a new solar driven mechanical vapor compression desalination plant with nano-filtration pretreatment operating at atmospheric pressure is developed for a production of 500 m³/d...

Sorption-based hybrid vapor compression chillers have been identified as a possible replacement for energy-intensive conventional compression chillers. The objective of the current work is to evaluate the system performance and the corresponding energy savings of a hybrid adsorption-compression chiller. The adsorption chiller works with silica gel/...

This study theoretically investigates the energetic and economic feasibility of three configurations of a solar-driven hybrid adsorption-compression cooling system using typical meteorological data of Cairo, Egypt. In Configuration-I, adsorption system is driven by solar collectors and vapor compression system is electrically powered. In Configurat...

To enhance the performance of vertical axis wind turbines, a new configuration using twisted blades in multi-stage Savonius rotors is developed. Accordingly, single-, two-, three-, and four-stage Savonius rotors with twisted blades are investigated and compared with a single-stage rotor at corresponding aspect ratios ranging from 1 to 4. To determi...

In the present paper, the system performance of a solar-driven hybrid adsorption-compression refrigeration system has been investigated theoretically using the typical meteorological data of Alexandria, Egypt. The required thermal and electrical energy of the hybrid adsorption-compression refrigeration system is attained using photovoltaic/thermal...

In this paper, theoretical investigation of an integrated solar-powered cooling system consisting of commercial photovoltaic/thermal (PVT) collectors and an adsorption chiller is performed. The performance is investigated under different climate conditions of the Middle East such as Alexandria in Egypt, Dubai in United Arab Emirates and Riyadh in S...

The Savonius vertical axis wind turbine offers several benefits as simple construction, low manufacturing, installation and maintenance costs, low operating wind speed, and independence of wind direction. However, the conventional single-stage Savonius rotors have negative torque values at a certain range of rotor angles and large torque variation...

Wind energy comprises one of several renewable resources of energy engineered to contain the global energy crisis. Although horizontal axis wind turbines (HAWTs) have proven to be effective in low turbulence and steady wind conditions, vertical axis wind turbines (VAWTs) potentially have the advantage in highly variable and turbulent regions. The S...

In this study, adsorption characteristics of water vapor onto several silica gel-based composites have been investigated experimentally. Adsorbent samples under investigation are silica gel powder (SGP), 98wt% SGP with 2wt% Polyvinylpyrrolidone (PVP) binder, 93wt% SGP, 2wt% PVP binder with 5wt% EG500 and 93wt% SGP, 2wt% PVP binder with 5wt% EG100....

It is important to determine the most optimal configuration of a Savonius vertical axis wind turbine that attains the best performance with a high self-starting ability. Thus, the effects of several design parameters including twist angle, overlap ratio, and endplates size ratio, along with the wind velocity on the performance of the Savonius wind...

Theoretical and experimental investigation of the thermal energy storage of an open adsorption system is presented. The theoretical model describes the mass and energy transfers in the system. The coupled energy and mass balance equations have been solved using the COMSOL™ software. The model was validated against laboratory experiments performed a...

The motivation of the present paper is to synthesis high packing density and thermal conductivity consolidated composite using silica gel powder (SGP) almost without affecting its porous properties. The effect of packing density, binder type and amount on porous properties as well as thermal conductivity were studied. Four types of binder, namely H...

This paper presents the thermo-physical properties of silica gel powder (SGP) consolidated composites for adsorption cooling and desalination applications. The motivation of this research is to develop high packing density and high thermal conductivity SGP consolidated composite without highly affecting the porous properties of parent SGP. The effe...

Biomasses are renewable resources and suitable precursors for synthesis of activated carbons (ACs). Two biomass sources: (i) Waste Palm Trunk (WPT) and (ii) Mangrove (M) are employed to synthesis activated carbons with huge surface area by chemical activation with potassium hydroxide (KOH). Thermophysical characteristics of the derived activated ca...

Adsorption cooling systems employs benign refrigerants and could be driven by solar energy or waste heat. Therefore, they are a feasible alternative to vapor compression cooling systems. This paper investigates the performance of metal-organic framework (MOF) ethanol based adsorption cooling cycle. Adsorption isotherms of ethanol onto MOF of type M...

This paper presents a review on physical adsorbent-adsorbate pairs for adsorption cooling applications. Adsorption isotherm models used to estimate adsorption equilibrium uptake of the studied pairs have been presented. Employing ideal adsorption cooling cycle, adsorption uptake difference along with the specific cooling capacity of various pairs h...

This study deals with the thermodynamic analysis of adsorption cooling cycle using consolidated composite adsorbents-ethanol pairs. The studied composites are named as c omposite A (50% Maxsorb III, 40% expanded graphite (EG), 10% binder) and composite C (70% Maxsorb III, 20% expande d graphite (EG), 10% binder). The Dubinin- Radushkevich (D-R)...

Adsorption of carbon dioxide onto highly porous activated carbon based consolidated composite adsorbent has been experimentally investigated. Experiments have been conducted at temperatures of 30, 50, 70 ºC and pressures up to 7 MPa using magnetic suspension adsorption measurement unit. The innovative adsorption isotherms data have been correlated...

Water vapor sorption kinetics of two polymer based sorbents has been experimentally measured at adsorption temperatures of 20, 30, 50, 70 and 80 °C using a magnetic suspension adsorption measurement unit. The experimental data is employed to commonly known adsorption kinetics approximations i.e. Linear driving force (LDF) model, Fickian diffusion (...

This study deals with the preparation and characterization of consolidated composite adsorbents for adsorption cooling application. The consolidated composites are a combination of activated carbon powder (ACP) namely Maxsorb III and some additives materials such as expanded graphite (EG) and binder. Composite samples with different mass ratios of...

An insulated storage tank has been added with adsorption cooling system run by solar heat collected by CPC panel. It has been expected and seen that the storage tank has a vital contribution in the performance of the chiller. The storage tank is connected with a solar heat driven single stage two bed basic adsorption chillers activated with silica...

In this study, consolidated composite adsorbents which are combinations of a highly porous activated carbon powder (Maxsorb III), expanded graphite (EG) and binder have been developed and characterized. Porous properties of the developed composite adsorbents have been investigated experimentally using Nitrogen adsorption. Adsorption equilibrium upt...

This paper presents an experimental investigation of adsorption equilibrium characteristics of natural gas onto granular activated carbon (GAC). Experiments have been conducted at adsorption temperatures ranging from 20 °C to 50 °C and pressures up to 10 bar. The measurements are based on measuring the adsorption uptake difference between two equil...

Adsorption (AD) cycle is recently pioneered for cooling and desalination applications. For water treatment, the cycle can be used to treat highly concentrated feed water, ranging from seawater to ground water and to chemically-laden waste water. This paper presents a review of the recent development of AD cycle and its hybridization with known conv...

Two polymer based sorbents PS-I and PS-II are analyzed for water sorption applications. Adsorption/desorption isotherms of water vapor onto PS-I and PS-II have been experimentally measured using a magnetic suspension adsorption measurement unit for adsorber temperature ranges 20-80 °C and evaporator temperature ranges 2-73 °C. The equilibrium adsor...

This paper presents experimental and theoretical investigations of adsorption characteristics of ethanol onto metal organic framework namely MIL-101Cr. Adsorption isotherms and kinetics of the studied pair have been measured gravimetrically using a magnetic suspension adsorption measurement unit and volumetrically employing a Quantachrome Autosorb...

Adsorption of water vapors onto silica-gel and two types of carbon based adsorbents (CBAs) has been experimentally investigated. Adsoption data has been analyzed for various adsorption models. The Guggenhein, Anderson. De-Boer (GAB) and Dubinin-Astakhov (D-A) models gave the good fit for silica-gel and CBAs respectively with an error of less than 5...

Adsorption equilibrium uptake of environment friendly refrigerant ethanol onto highly porous activated carbon based adsorbents has been experimentally investigated by using a magnetic suspension balance adsorption measurement unit (MSB-VG-S2). Adsorbents used in the present study are parent Maxsorb III, H2 and KOH-H2 surface treated Maxsorb III. Ex...

The purpose of our study is to develop a compact adsorption refrigeration system. Use of high pressure refrigerants, such as hydrofluorocarbons (HFCs) or CO_2 is one of approaches to reduce a system size because the volume flow rate of refrigerant can be significantly reduced. In our previous studies, adsorption equilibrium of activated carbon-R32...

This paper presents experimental and theoretical investigation of decentralized desalination system based on a humidification-dehumidification (HDH) process. HDH is one of the methods that employed in the decentralized systems in remote areas where there is lack of experienced operators, maintenance and water resources. HDH is suitable for remote a...

The paper compared the performances of adsorption refrigeration/heat pump systems between the silica gel-water and the activated carbon-ethaonol as adsorbent-adsorbate combinations. The system performance was predicted in a wide range of heat source/sink by simulation. The adsorption isotherm and kinetics of the silica gel-water pair were taken fro...

This paper presents an experimental investigation of adsorption isotherms and kinetics of promising adsorbent/refrigerant pairs towards the performance improvement of adsorption cooling systems. Adsorbents used in the present study are (i) parent Maxsorb III, (ii) KOH-H2 treated Maxsorb III, and (iii) a metal organic framework (MOF) material namely...

In the present study, an experimental analysis for adsorption of water onto carbon based adsorbent i.e. activated carbon powder (AC) has been presented. An experimental system has been employed to measure adsorption isotherms of AC and RD type silica-gel with water. Experimental data for AC have been correlated using an appropriate adsorption isoth...

Adsorption isotherms of ethanol onto surface treated activated carbons, namely H 2 treated Maxsorb III and KOH-H 2 treated Maxsorb III have been investigated experimentally. The magnetic suspension adsorption measurement unit of type MSB-VG-S2 is used for measuring the equilibrium uptake over adsorption temperatures range from 30 to 70 ºC and evapo...

This study presents an experimental investigation of adsorption kinetics of ethanol onto a highly porous activated carbon powder namely Maxsorb III. Instantaneous adsorption uptake of ethanol is measured using magnetic suspension adsorption measurement unit (MSB-VG-S2). Experiments have been carried out at different adsorption temperatures ranging...

The objective of this article is to improve the performance of thermally powered adsorption/cooling systems by selecting a new adsorbent/refrigerant pair. Adsorption equilibrium data of R134a onto granular activated carbon (AC) and Unitika activated carbon fiber (ACF) of type (A-20) have been measured experimentally using Rubotherm ISOSORP 2000 wit...

Performance enhancement of adsorption cooling system has been required for commercial use. Therefore, revealing details of adsorption phenomena are important for optimizing adsorber/desorber heat exchanger which is the bottle-neck of the system. This study deals with the experimental investigation of ethanol vapor adsorption on activated carbon fib...

This paper aims to address the effect of using classical Linear Driving Force (LDF) model on the performance of adsorption chillers. A comparative study between the well known LDF equation and the Fickian diffusion (FD) model has been conducted. Two adsorbent/refrigerant pairs namely, RD silica gel/water and “CaCl2 confined to KSK silica gel”/water...

This paper presents adsorption isotherm data of CO2 onto two different types of highly porous activated carbons (ACs) for temperatures ranging from (−18 to 80) °C and pressures up to 10 MPa. The assorted adsorbents are activated carbon fiber (ACF) of type A-20 and activated carbon powder of type Maxsorb III. Adsorption isotherm data have been obtai...

In this chapter, the Boltzmann Transport Equations (BTE) is used to formulate the transport laws for equilibrium and irreversible thermodynamics and these BTE equations are suitable for analyzing system performance that are associated with systems ranging from macro to micro dimensions. In this regard, particular attention is paid to analyze the en...

This article presents the adsorption isotherms of HFC-134a and activated carbon Maxsorb III measured using the constant-volume–variable-pressure method. The adsorption isotherms cover temperature ranges from 293 to 338 K and pressures up to 0.7 MPa. The trends of the experimental isotherms for activated carbon are found to be identical in all cases...

The thermodynamic property surfaces of R507A, R134a, and n-butane on pitch-based carbonaceous porous material (Maxsorb III) are developed from rigorous classical thermodynamics and experimentally measured adsorption isotherm data. These property fields enable us to compute the entropy, enthalpy, internal energy, and heat of adsorption as a function...

In this chapter, the Boltzmann Transport Equations (BTE) is used to formulate the transport laws for equilibrium and irreversible thermodynamics and these BTE equations are suitable for analyzing system performance that are associated with systems ranging from macro to micro dimensions. In this regard, particular attention is paid to analyze the en...

Adsorption equilibrium data are the most essential information needed for the design and development of adsorption systems. It describes the amount of adsorbate that could be adsorbed onto the surface of a certain mass of adsorbent at a given equilibrium pressure and temperature. Even though the practical adsorption processes are unequilibrium and...

The thermodynamic property surfaces for a single-component adsorbent + adsorbate system have been derived and developed from the view point of classical thermodynamics. These thermodynamic frameworks enable us to compute the specific heat capacity, partial enthalpy and entropy for the analyses of adsorption processes thoroughly. A theoretical frame...

This paper presents adsorption isotherms of R-134a (HFC-134a) on highly porous pitch based activated carbon (Maxsorb III) in the temperature range of 5–70°C and pressures up to 12bar, using desorption method. The experimental data have been fitted with the Dubinin–Astakhov (D–A) isotherm equation. The adsorption isotherms of R-134a on Maxsorb III o...

This paper presents the isothermal characteristics of methanol onto two specimens of activated carbons namely Maxsorb III and Tsurumi activated charcoal. Dubinin Raduskevich (D-R) equation is used to correlate the adsorption isotherms and to form the pressure–temperature–concentration diagram for both of the assorted pairs. Experimental results sho...

This article deals with the experimental study of adsorption rate of R507A on highly porous activated carbon of type Maxsorb III by constant volume variable pressure (CVVP) method over a temperature ranging from 20 to 60℃. These data are useful for the operation of adsorption chillers and these data are unavailable in the literature. Data obtained...