Shek Rahman

Shek Rahman
University of Sharjah | US · Department of Sustainable and Renewable Energy Engineering

PhD ( NUS, Singapore). CEng (UK)

About

42
Publications
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1,006
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Publications

Publications (42)
Article
In order to prolong the cycle life of the battery pack for electric vehicles or hybrid electric vehicles, phase change materials (PCMs) are employed effectively for the battery thermal management (BTM) systems. Utilizing the cooling system based on PCMs for BTM can lead to the desired cooling effect yielding the most appropriate temperature distrib...
Article
The current study aims to optimize the osmotic dehydration parameter of a food product by adjusting the quantities of several osmotic agents. In this study, a cube-shaped Zucchini is utilized as an example food product. Maltose, fructose, lactose, and fructo-oligosaccharide (FOS) were used as osmotic agents at varying concentrations (30%, 40%, and...
Article
Hybrid photovoltaic-thermal (PV-thermal) is a promising technology that could harness the maximum output from solar energy. In this work, a new thermal management system based on an innovative design of PV-thermal is designed and investigated under outdoor weather conditions in Sharjah, UAE. A numerical model is also developed to evaluate the therm...
Article
In the present work, Multi-Wall Carbon Nanotubes (MWCNT)/water nanofluids are used to increase the performance of a shell and tube heat exchanger (STHX) while reducing energy consumption and overall cost. MWCNT/water with 0.3% and 0.05% volume fractions were studied for stability and thermophysical characteristics. At a 0.3% volume fraction, a subs...
Article
Full-text available
A renewable energy source, especially solar energy, is one of the best alternatives for power generation in rural areas. Organic Rankine cycle (ORC) can be powered by a low-grade energy source, suitable for small-scale power production in rural areas. This study investigates the combined power generation and cooling system using the combination of...
Article
Metal–air batteries are a promising technology that could be used in several applications, from portable devices to large-scale energy storage applications. This work is a comprehensive review of the recent progress made in metal-air batteries MABs. It covers the theoretical considerations and mechanisms of MABs, electrochemical performance, and th...
Article
A novel g-C3N4/VC composite was prepared by adopting simple hydrothermal treatment without using any additives from bulk g-C3N4 and Vulcan XC-72R (VC) in different ratios. Further, the resulting composite materials were used as a support for the synthesis of Cu2O NPs. The use of g-C3N4/VC not only acts as a support for the Cu2O NPs but also it form...
Article
Full-text available
The main goal of this research is to develop and apply a robust Artificial Neural Networks (ANNs) model for predicting the characteristics of the osmotically drying treated potato and apple samples as a model heat-sensitive product in vacuum contact dryer. Concentrated salt and sugar solutions were used as the osmotic solutions at 27◦C. Series of e...
Article
This investigation conducted a thorough review of the application of nanomaterial to improve the performance of phase change material (PCM) for energy storage application. It was deduced that issues pertaining to thermal conductivity coupled with a leakage are key factors restricting the wider application of PCM. In this regard, the application of...
Article
Full-text available
This investigation summarised the application of nanofluids in heat exchangers (HExs). The quest for heat devices with quick response for the industrial sector is still a major challenge that has been an active research direction over the years. Addressing this issue is likely to increase the capacity of several industries. There is a direct relati...
Article
Full-text available
An experimental study combined with a mathematical modeling of vacuum drying of cocoa beans was carried out to enhance the drying kinetics without compromising the quality of dried products. Experiments were conducted to compare the effects of variation of temperature and pressure on the drying process. The temperature was varied between 40 and 60...
Article
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End pumped lasers are highly efficient lasers particularly in diode lasers using micro lenses. The common cooling method for end-pumped systems is using water jacket or copper tube surrounding the laser rod. In this paper, the temperature distribution within a water jacket and a fiber laser end pumped by a top hat beam is studied analytically. The...
Article
The thermal and thermodynamic performance of parabolic trough solar collector (PTC) could be enhanced by using nanofluids due to their enhanced thermophysical properties. In this work, numerical and experimental investigations were carried out to study the effect of suspended industrial-grade multi-walled carbon nanotubes (MWCNTs) in distilled wate...
Article
Membrane distillation (MD) is an effective water treatment process with relatively low cost compared to conventional membrane processes. This study investigates several factors affecting the performance of the MD membrane such as fouling, porosity, pore size, mechanical stability, contact angle, salt rejection, and other physical and thermal pro...
Article
Full-text available
A study on mass transfer using new coating materials (namely alginic acid and polygalacturonic acid) during osmotic dehydration—and hence in a laboratory-scale convective dryer to evaluate drying performance—was carried out. Potato and apple samples were examined as model heat-sensitive products in this study. Results indicate that the coating mate...
Article
Full-text available
This work aims to maximize the drying-rate of the cocoa beans by controlling the values of temperature, pressure, and moisture contents. The drying-rate is maximized by defining the optimal operating conditions. Using the experimental data, obtained from the drying-rate process, a robust model that describes the drying-rate of the cocoa beans is ge...
Article
Full-text available
A novel design of a portable solar thermoelectric refrigerator is proposed in this study. The cooling effect of the thermoelectric module is utilized to provide cooling to the refrigerator space. To use the full potential of the thermoelectric module (TEM), the heat rejected from the hot side of the module is harnessed for a low-temperature heating...
Article
Full-text available
The aim of this project is to design a solar thermal absorption air conditioning system that operates under UAE climate conditions. In absorption system, compressor which is normally used in conventional AC system, replaced by a chemical cycle that consists of a generator, absorber, pump, and expansion valve, while the rest of the components such a...
Article
Full-text available
This work presents a novel solar powered air-conditioning system that operates under UAE climate conditions. Distinct passive techniques and refrigerant-based nanofluids, termed as ‘‘Nano refrigerants’’ were investigated to enhance the system performance. Results suggest that the proposed design of using passive techniques such as: roofing reflecti...
Article
Full-text available
Present work is focused on building a TRNSYS simulation model of solar water heating (SWH) system using heat pipe evacuated tubes, hybridized with conventional fuel (i.e., natural gas) backup to provide uninterrupted thermal energy supply. An experimental facility was developed to validate the simulated model. Further, the performance of hybrid eva...
Article
Boiler is a widely used steam generating system in industries and power plants. A significant portion of the world energy consumption is being used in boilers. A small improvement on the boiler efficiency will help to save a large amount of fossil fuels and to reduce CO2 emission. This study describes the amount of energy used in boilers, ways empl...
Article
Background: Appropriate design and development (in terms of mechano-chemical properties) of scaffold is essentially important for scaffold-based tissue engineering. Methods: In this study, scaffolds were fabricated using a desktop robot based rapid prototyping (DRBRP) system that was developed in-house. Poly lactic acid (PLA) and calcium carbonate...
Experiment Findings
Abstract: The osmotic dehydration plays an important role for preserving the products from spoilage in which it prevents any growth of toxic microorganisms. It improves the quality of the product in the food industry such as color, texture and flavor characteristics by using various types of drying. The solar dryer has been proposed because it ope...
Article
Full-text available
Osmotic pretreatment is an effective way of reducing water from the biological products as well as simultaneously accelerating the drying kinetics. This research investigates the effect of osmotic pretreatment on the biological products in a vortex tube atmospheric freeze-drying (AFD) system. To facilitate the atmospheric freeze-drying in a laborat...
Article
Full-text available
The objective of this research was to develop an atmospheric freeze drying system for heat sensitive materials. A laboratory scale atmospheric freeze drying system consisting of a vortex chiller was designed and fabricated. A vortex tube was employed to convert compressed air into a subzero and a hot air stream. The system used simultaneous applica...
Article
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This paper presents two mathematical models for drying mushrooms considering the shrinkage effect. Both the models consider the physical changes of mushrooms during drying using the diffusion equation. A convective term is presented in the first model while, in the second model, the effective diffusion co-efficient is employed. Although the diffusi...
Article
This paper presents an economic optimization of evaporator and air collector area of a solar assisted heat pump drying system. Economic viability of solar heating systems is usually made by comparing the cost flows recurring throughout the lifetime of the solar and conventional alternative systems. Therefore, identification of optimum variables by...
Article
Full-text available
Vacuum freeze drying has been the benchmark technology for making high-quality dried products. This technique, however, is expensive due its high fixed and operating costs. Interest in atmospheric freeze drying (AFD) has increased in recent years as it yields high product quality while reducing the net energy consumption in comparison with vacuum f...
Article
Full-text available
A three-dimensional (3D) computational fluid dynamic simulation of a vortex tube is carried out to examine its flow and thermal characteristics. The aim of this work is to model the performance of the vortex tube and to capture the highly swirling compressible flow behavior inside the tube for an understanding of the well known temperature separati...
Article
Atmospheric freeze drying (AFD) in a vibro-fluidized bed dryer coupled with an adsorbent and multimode heat input is proposed for dehydration of food products. An experimental setup was designed and built to permit simultaneous application of convection, conduction and radiation heat input to the drying material above its freezing point to ensure s...
Article
Full-text available
This article presents results of an experimental study of (AFD); atmospheric freeze‐drying which uses a vortex tube to produce low temperature air, as an alternative to vacuum freeze‐drying (VFD). An experimental setup was designed and built to permit simultaneous application of convection, conduction and radiation heat input to the drying material...
Article
Full-text available
This article presents a study of a novel fixed-bed atmospheric freeze-dryer using a vortex tube to generate cryogenic temperature air for drying and multimode heat supply. A two-layer moving boundary model was developed to simulate the variation of the transient moisture content distribution in the drying product in the form of a thin slab, sublima...
Article
Full-text available
A solar assisted heat pump dryer has been designed, fabricated and tested. This paper presents the performance of the evaporator-collector and the air collector when operated under the same meteorological conditions. ASHRAE standard procedure for collector testing has been followed. The evaporator-collector of the heat pump is acting directly as th...
Article
Full-text available
Atmospheric freeze drying (AFD) in a vibro-fluidized bed dryer coupled with an adsorbent and multimode heat input is proposed for dehydration of food products at lower cost than the traditional freeze-drying process under vacuum. The aim of this project is to study the proposed AFD system using a vortex tube to produce low-temperature dry air, an a...
Article
Full-text available
Wet particles are often difficult to dry due to their stickiness and tendency to form lumps. Mechanical vibration can assist in separating such particles as well as in mixing beds of dissimilar particles if necessary. Delumping also exposes surfaces for evaporation. The objective of this experimental project is to design, build and test a laborator...
Article
Full-text available
An experimental study of osmotic dehydration (OD) of selected heat-sensitive products was carried out in a laboratory-scale vacuum contact dryer. Cubes of potato and apple were examined as model heat-sensitive objects. Experiments were conducted at different conduction heat input levels with wall temperatures in the range 35–45C under vacuum and al...
Conference Paper
Full-text available
This paper presents results of an experimental study of atmospheric freeze drying (AFD) using a vortex tube, to produce low temperature air, an alternative for producing dried food products of high quality, which is comparable with vacuum freeze drying but at considerably lower cost. An experimental setup was designed and built to permit simultaneo...
Article
Full-text available
A two-dimensional liquid diffusion model was developed to predict the variation of transient moisture content and temperature distribution within model composite food products. Rectangular-shaped potato and apple slices were used to form the model composite samples for experimental tests. To verify the predictions of the theoretical model, a series...
Article
Full-text available
A solar-assisted heat-pump dryer and water heater has been designed, fabricated and tested. The performance of the system has been investigated under the meteorological conditions of Singapore. The system consists of a variable-speed reciprocating compressor, collector evaporator, storage tank, air-cooled condenser, auxiliary heater, blower, dryer,...

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