Mohammad H. Ahmadi

• Associate Professor
• University of Shahrood

The increasing demand for hydrogen as an energy carrier requires the development of efficient and sustainable production strategies. Methane reforming is a widely used method for hydrogen production, and catalysts play a crucial role in optimizing this process. This paper provides a comprehensive review of the catalytic aspects of methane reforming...

In this study, sawdust from a paper factory in north Iran was selected as the biomass resource to supply some of this region's electricity, cooling, and heating demand. Accordingly, a steam Rankine cycle (SRC) based tri-generation system is designed, and exergy analysis is conducted. According to the modeled cycle, the generating power of the proce...

Heat exchangers are widely used in different chemical industries and energy systems. Among different types of heat exchangers, shell and tube heat exchangers are among the most conventional ones that have significant share in the market and industry. Performance of shell and tube heat exchangers is affected by a variety of factors which can lead to...

Humidification and dehumidification (HDH) desalination units compared with the other thermal desalination systems have relative advantages due to working under ambient pressure and low temperatures and are more attractive. In this research, the application of an HDH desalination unit with indirect‐contact of air and water streams in a steam power p...

The heat transfer efficiency of a thermal energy storage unit (TESU) can be improved by the addition of novel longitudinal fins. A series of TESUs are analyzed using the finite volume method (FVM) to determine the effect of fin angle on the heat transfer performance. As the fin angle increases, the TES rate first increases, then decreases, reaching...

This study presents the effect of inert gas flow inlet positioning and orientation on the conversion efficiency of the proposed solar thermochemical reactor for hydrogen production. The nitrogen gas was used as (i) a reducing agent, (ii) a cooling agent to control the porous matrix temperature and (iii) removing oxygen from the STCR chamber. The re...

Due to the critical water situation in the world and the need for freshwater, the use of desalination systems is very common. One of the main problems of using such devices is the production of a high-concentration brine stream, which causes environmental problems. Therefore, the need to use systems that reduce the level of salt water to zero (zero...

Guest editorial introducing the special issue on the International Conference on Sustainable Energy Sources, Technologies and Systems 2023.

The present study’s goal was to investigate the efficiency of applying carbon/water Nanofluid and triangular baffles in the double-tube heat exchangers. The Reynolds number was in the range of 4000 to 14,000, and the carbon/water Nanofluid, which was with various volume fractions ranged between 0.1 and 0.3 volume percentages, was applied. Moreover,...

Performance improvement of heat exchangers is important since their size and manufacturing cost can be decreased. This study aims to evaluate two techniques, namely use of nanofluid and employment of vortex generator (VG) applicable in performance improvement of a fin-plate heat exchanger. In the present article, a numerical investigation is carrie...

The surging demand for electricity, fueled by environmental concerns, economic considerations, and the integration of distributed energy resources, underscores the need for innovative approaches to smart home energy management. This research introduces a novel optimization algorithm that leverages electric vehicles (EVs) as integral components, add...

Considering the issues related to the usage of fossil fuels namely the environmental pollutants and fluctuations in their cost, development of renewable energy technologies is necessary and inevitable for sustainable energy supply in future. Geothermal energy is advantageous compared with solar and wind in term of availability in all hours of a day...

The search for an effective solution to improve performance and emission characteristics of internal combustion (IC) engines used in the commercial sector is regarded as one of the most important and essential issues in recent years due to increasing levels of pollution. Nanoparticles with their additive ability to increase fuel reactivity and atom...

Drinking water is a crucial need for human survival and solar stills (SSs) have emerged as a cost‐effective solution to meet this need from an economic point of view. In this work, the working of various SSs, their productivity factors, and various devices that can be integrated to improve their efficiency have been studied. The conversion of salin...

In this paper, a multilayer perceptron (MLP)-type artificial neural network model with a back-propagation training algorithm is utilized to model the bubble growth and bubble dynamics parameters in nucleate boiling with a non-uniform electric field. The influences of the electric field on different parameters that describe bubble’s behaviors includ...

Due to the increasing demand for electrical energy, efforts to increase the thermal efficiency of the steam and gas power plants have led to extensive reform in these cycles. One of these common reforms is employing a conventional combined gas‐steam cycle. In combined cycle power plants that are built to produce power, a significant portion of the...

Integrated energy systems are one of the potential options for buildings that can reduce emission. In this research study, the energetic and economic performance of a micro-gas turbine combined heating and cooling plant coupled with a solar PV is analyzed for an office building in Iran. For each analysis, two different scenarios have been performed...

A fabric air dispersion system (FADS) is a type of flexible air supply system that integrates air transmission and distribution. This innovative system has the potential to address common issues such as uneven air supply and surface condensation, which are often associated with traditional ventilation systems. Existing numerical simulation studies...

The present paper investigates the magnetohydrodynamics Casson fluid flow with porous medium. The Cu-water nanofluid is used to investigate further analytical results. Thermal radiation is considered along with the Cattaneo-Christov heat flux model and then solved analytically, then expresses the closed forms analytical solution in terms of two var...

Background & Objectives: Beta-thalassemia is one of the complex diseases that causes many social and economic problems for the patient and his family. This study aimed to investigate factors influencing the birth of thalassemia (intermedia or major) in family members with thalassemia major in Sistan and Baluchistan province.Materials & Methods: Thi...

Considering the waste of fresh water in a 256 MW steam power plant located in the southeast of Iran, and to compensate a part of its water consumption, a humidification-dehumidification (HD) desalination system is proposed. Because of sedimentation problems in indirect-contact HD systems, in this research, the application of direct-contact HD metho...

Heating and cooling are responsible for considerable portion of final energy consumption in the world especially in the residential sector. In order to decrement the pollutants and energy consumption, it is essential to apply promising technologies with proper performance and reliability. Regarding the better performance of heat pumps, in term of e...

This chapter reviews nanofluid applications in porous media. Heat transfer research continues to find improved solutions for optimized heat transfer enhancement in the performance of energy devices. Amidst different methods, the adoption of nanofluids continues to improve the thermal behavior of energy systems. So, the superior thermal characterist...

In this study a 2D cubic chamber model filled with paraffin is analyzed with and without the inclusion of magnetic Fe3O4 nanoparticles at concentrations of 0.5, 1, 1.5 and 2 wt%, and an external magnetic field of intensities 0.005, 0.01, 0.015 and 0.02 T. It is ascertained that adding magnetic nanoparticles leads the horizontal temperature gradient...

In this paper, a multilayer perceptron (MLP) artificial neural network (ANN) with a back-propagation (BP) training algorithm is applied for modeling thermophysical properties and subcooled flow boiling performance of Al2O3/water nanofluid in a horizontal tube. The influence of nanofluid concentration, heat flux, and flow rate on different thermophy...

A heat pipe is an energy-efficient heat transfer device that relies on evaporation and condensation processes for energy transfer. The main purpose of this study is to simulate a two-phase closed thermosyphon, at moderate temperature, that can be used in industrial applications such as steam power plants. After creating a computational network in t...

Engineering applications including food processing, wastewater treatment, home heating, commercial heating, and institutional heating successfully use unglazed transpired solar collectors (UTCs). Trapping of solar energy is the prime goal of developing an unglazed transpired solar collector. The UTC is usually developed in and around the walls of t...

This study is focused on presenting a novel approach for the cogeneration of liquid carbon dioxide (LCO2) and liquefied natural gas (LNG). The main idea of this development is to use air for storing and producing energy, meanwhile, transferring cold energy for the liquefaction process of natural gas. Therefore, a mixed refrigeration cycle and liqui...

The price of constructing hydrogen generation units is very high and sometimes it is not possible to build them in the desired location, so the transfer of hydrogen from the hydrogen generation system to the units that need it is justified. Since the storage of hydrogen gas needs a large volume and its transportation is very complex, so if hydrogen...

The drinkable water storages shortage is one of the main obstacles that many societies are envisaged with. In addition, the water content of humid air is known as the main storage of drinkable water for the future. In this paper, the energy and exergy analysis of a solar driven atmospheric water generator which contains an absorption refrigeration...

A new engine patent was awarded to Meletis and Georgiou in 1998. The engine is with vane rotor and the rotor is fully balanced and symmetric. It also has an exhaust gas recirculation (EGR) process. Symmetric rotor mechanism leads much smother running, and EGR process makes working fluid (WF) preheated before entering to compression stage which prov...

The rising demand for electricity, along with the need to minimize carbon footprints, has motivated academics to investigate the flexible and efficient integration of energy conversion technologies. A novel hybrid power generation system based on environmentally friendly and cost-effective technologies to recover the waste heat of a working gas tur...

Considering the high installation cost of renewable systems and reliance on weather conditions, as well as high energy consumption in post-combustion carbon capture system, the use of the combined method can assist to achieve net-zero carbon emission. Carbon dioxide (CO2) capturing based on renewable energies is introduced as a practical emission-c...

This paper investigates a safety control room with 18 kW of cooling load, where a parabolic trough collector is connected to an R718 ejector air-conditioning subsystem. Engineering Equation Solver is used as a programming tool to conduct the dynamic study of the proposed system. After model validation, the optical thermal and exergy efficiency of s...

The consequence of magnetohydrodynamics (MHD) flow on entropy generation analysis and thermal radiation for carbon nanotubes via a stretched surface through a magnetic field has been discovered. The governing partial differential equations are altered into ordinary differential equations with the aid of the similarity variable. Here, water is consi...

Despite the attractiveness of Photovoltaic (PV) cells for electrification and supplying power in term of environmental criteria and fuel saving, their efficiency is relatively low and is further decreased by temperature increment, as a consequence of absorption of solar radiation. In order to prevent efficiency degradation of solar cells due to tem...

Reliability centered maintenance (RCM) is a new strategic framework for evaluating system maintenance requirements in its operating conditions. Some industries employ predictive maintenance strategies in addition to preventive maintenance (PM) strategies, which increase production costs. As the breakdown maintenance (BDM) technique is used, the mai...

The integrated natural gas liquids (NGL)/liquefied natural gas (LNG) processes take precedence over standalone NGL and LNG units due to the lower investment and operating costs. Several studies have been conducted to improve the performance of integrated schemes, but few have looked into the controllability of these configurations. For the first ti...

The purpose of this study is to investigate the computational fluid dynamics to find the effects of Reynolds number, different volume fractions of aluminum oxide nanofluid and different heat fluxes in heat transfer performance (Nusselt number) in a helical tube. This simulation was investigated at Reynolds number range 2000 and 10,000 and volumetri...

The use of different energy storage materials can have a high effect on the water productivity of solar desalination. This study evaluates the impact of magnetic powders on modified solar still (MPSS) performance and compares the results with conventional solar still (CSS). Black iron oxide magnetic powder was selected to increase solar radiation a...

This study was aimed at investigating the computational fluid dynamics to find the effects of different angles of the twisted tape as well as the copper nanofluid concentration changes on heat transfer performance (Nusselt number and convective heat transfer coefficient) in a tube containing nanofluid under a constant wall flux. This simulation was...

In this study, energy assessment is performed for an industrial turbocharged diesel engine integrated with a novel waste heat recovery (WHR) system. The exhaust energy is used in inverted Brayton cycle (IBC) for waste heat recovery purpose. Also, the heat energy from IBC heat exchanger is used as the heat source for the organic Rankine cycle (ORC)...

In the present study, two-phase flow and forced-convection heat transfer of hydrogen gas (H2) in a solar finned and baffled channel heat exchanger (SFBCHE) is studied numerically. The effect of different obstacles in the channel is addressed. A H2 heat transfer fluid (HTF) having a high thermal conductivity with the baffling technique is implemente...

Electric vehicles (EV) played an important role fighting greenhouse gas emissions that contributed to global warming. The construction of the charging pile, which was called as the "gas station" of EV, developed rapidly. The charging speed of the charging piles was shorted rapidly, which was a challenge for the heat dissipation system of the chargi...

The objective of this article is to study the work carried out in heat transfer augmentation using active and passive techniques. A comprehensive summary of the work is highlighted to showcase the strength of these techniques in terms of enhancement in heat transfer. In this work, research studies done in the area of electrohydrodynamic, magnetic f...

Conservation of energy and reduction of carbon dioxide footprint are among the most crucial global challenges faced by humanity. Dozens of solutions have been so far introduced to address this issue. Nano‐phase change materials (nano‐PCMs) are new emerging technology that are vastly being studied which are believed to minimize energy waste. This st...

In recent decades, there has been an increasing trend toward the technical development of efficient energy system assessment tools owing to the growing energy demand and subsequent greenhouse gas emissions. Accordingly, in this paper, a comprehensive emergy-based exergoeconomic (emergoeconomic) method has been developed to study the biomass combust...

Over the last decade, the total primary energy consumption has increased from 479 × 1015 BTU in 2010 to 528 × 1015 BTU in 2020. To address this ever-increasing energy demand, as well as prevent environmental pollution, clean energies are presented as a potential solution. In this regard, evaluating and selecting the most appropriate clean energy so...

A technical–economic assessment was carried out in this study to determine the possibilities for wind and solar power generation in Afghanistan’s Helmand province. The results showed that most of the province has a solar irradiance of over 400 W/m2, and also showed that wind and solar power generated in the province can be up to twice as cheap as t...

The efficiency of photovoltaic cell is highly temperature‐dependent; therefore, the performance of these solar panels would be increased by decreasing the temperature. In this research, a novel integration of coupling thermal photovoltaic panels with thermoelectric generator module (PVT‐TEG) is investigated for possible application in reducing cell...

Heat and flow pattern of a vertical free jet impinging on a hot disk were numerically investigated. A cylinder with various thicknesses and materials exposed simultaneously to uniform heat flux on one side and a free impinging jet on the other side is simulated by ANSYS Fluent 19.3. For simulations, the thermal boundary condition on the hot surface...

In this investigation, a hybrid energy conversion system is proposed and evaluated for energy, exergy, and environmental criteria for generating power and freshwater. The system comprises of a Humidifier Dehumidifier Desalination (HDD) system for producing freshwater, an organic Rankine cycle system for generating electric power, and a solar Parabo...

Today, the use of renewable energy is increasing day by day, and this development requires the optimization of these technologies in various dimensions. Solar systems have a higher acceptance due to their high availability and accessibility; the most common solar technology is photovoltaic cell. In this research, modeling was done to achieve the mo...

Increasing the power grid peak in the summer time causes power outages in industries and residential areas in Iran. The most obvious example of this issue is the power outages in the summer of 2018. Management of the demand-side is the most important strategy to reduce the grid peak due to the high cost of the development of the power plant capacit...

This paper presents reliability, availability, and maintainability (RAM) analysis framework for evaluating the performance of a circulation system of water (WCS) used in a coal-fired power plant (CFPP). The performance of WCS is evaluated using a reliability block diagram (RBD), fault tree analysis (FTA), and Markov birth–death probabilistic approa...

Chemically enhanced oil recovery techniques have been considered efficient tertiary methods to improve the oil production from oil reservoirs regarding their compatibility with the reservoir characteristics. Moreover, gravity segregation and viscous fingering during carbon dioxide flooding would be the main problems of oil recovery techniques. In t...

Owing to enormous increase in the automobile population, traditional petroleum fuels for internal combustion engines will be usable only for a few years. Moreover, by releasing toxic emissions into the atmosphere at higher levels these fuels create severe environmental problems. In general, Carbon-monoxide (CO), Unburnt hydrocarbons (UHC), and smok...

In this investigation, a solar-driven multi-generation plant is developed and studied through exergy assessment. The developed integrated system is designed to provide power, cooling, freshwater, and hot water for an industrial complex. The designed layout consists of solar parabolic trough collectors as the main driver which can provide the drivin...

Agriculture and energy are inextricably connected; many energy systems can be driven by biomass supplied from agricultural waste products. In this study, a combined biomass/natural gas fed multi-generation system, prodcuing cooling, heating, and power is investigated from exergetic and thermo-economic standpoints. The system consists of four susbsy...

Increasing the performance of heat exchangers is one of industry’s most pressing challenges. Pulsating heat pipes (PHPs), as a novel technology with high-performance, are broadly used in solar distilled water and systems solar water heaters. In the present work, the impact of three nanofluids including zirconium dioxide (ZrO2), bismuth ferrite (BiF...

The regasification of liquefied natural gas provides considerable cold energy that would have practical potential in different industrial fields and makes a suitable option for integrating with cryogenic air separation systems that requires a significant amount of energy. In this research, two-column cryogenic air separation units are driven with s...

The optimization of outdoor thermal comfort has become the keystone to guarantee the healthy and comfortable use of outdoor spaces. This study aims to optimize the outdoor thermal comfort through vegetation parameterization in a boulevard located in Guelma city, Algeria during summertime. However, two main parameters were investigated, species and...

Analyzing the combination of involving parameters impacting the efficiency of solar air heaters is an attractive research areas. In this study, cost-effective double-pass perforated glazed solar air heaters (SAHs) packed with wire mesh layers (DPGSAHM), and iron wools (DPGSAHI) were fabricated, tested and experimentally enhanced under different ope...

The improvement of the efficiency of heat exchangers has always been one of the most critical concerns of industry. Pulsating heat pipes are a new and high-efficiency technology in the field of heat transfer. Pulsating heat pipes are widely used in solar water heaters, solar water desalination systems, etc. In this study, the effect of different na...

The most of introduced schemes for the co-production of natural gas liquids (NGL) and liquefied natural gas (LNG) are designed as integrated configurations from the base. Furthermore, due to the high complexity of these structures single-objective optimizations are usually applied in this field. The present paper proposes a new NGL/LNG configuratio...

Carbon nanotube (CNT) nanofluid have a broad application prospect due to their excellent thermal properties, but they are limited by the high experimental costs. In this study, the effects of the dispersant concentration, mass fraction, temperature, and standing time on the thermal conductivity (TC) of CNT-nanofluid were analyzed experimentally. Be...

This article studied the load frequency control (LFC) of a multi-source microgrid with the presence of renewable energy sources. To maintain a sustainable power supply, the frequency of the system must be kept constant. A Proportional–Integral–Derivative (PID) controller is presented as a secondary controller to control the frequency of the microgr...

This study is a model of artificial perceptron neural network including three inputs to predict the Nusselt number and energy consumption in the processing of tomato paste in a shell-and-tube heat exchanger with aluminum oxide nanofluid. The Reynolds number in the range of 150–350, temperature in the range of 70–90 K, and nanoparticle concentration...

As an external combustion engine, the Stirling engine has low noise and can also easily use renewable and modern energies, such as solar energy. In this study, the dynamic synthesis of the alpha-type Stirling engine will be discussed. By combining the Stirling engine's thermodynamic and dynamic models, it is possible to predict the thermal efficien...

Various studies have been made to improve the efficiency of the solar still. These studies had devoted to the combination of solar collectors with solar still. This article proposes the use of all forms of solar thermal or photovoltaic energy. In addition, photovoltaic electric storage systems convert them to thermal energy that increases the tempe...

This research is proposed to fully investigate the performance of a single‐effect water/lithium bromide absorption chiller driven by geothermal energy. Since absorption cycles are considered as low‐grade energy cycles, this innovative idea of rejecting fluid from a single‐flash geothermal power plant with low‐grade energy would serve as efficient,...

Heat pipes are useful devices in heat transfer and particularly, in cooling systems. Given the high demand for cooling systems in various applications, an improvement in the performance of heat pipes has gained much attraction in recent years. In this study, the effects of utilizing working fluids with different thermal properties on the performanc...

New and innovative solutions are being developed to overcome the challenges of detrimental effects that the traditional energy systems cause. This means that sustainable methods are implemented to do so, noting that when such developments are taken into consideration and are studied, this leads to a significant drop in the cost of renewable energy...

The main purpose of this paper is to study the thermodynamic, economic, and environmental aspects of a integrated system combined cooling, heating, and power generation system empowered by biomass and natural gas. Eco-Indicator 99 method is utilized to quantify the environmental impact. The proposed system consists of four main subsystems producing...

In this study, a high-temperature tubular solid oxide fuel cell (SOFC) was modeled and optimized from thermodynamical and electrical point of view. The optimization was carried out by the fast and elitist multi-objective genetic algorithm approach: NSGA-II (non-dominated sorting genetic algorithm II). The modeled fuel cell was designed with an inte...

The majority of existing water is saline water and it is crucial to find approaches and technologies to desalinate water in an efficient and reliable manner. Solar energy can be applied in desalination systems in order to provide required heat or generate needed electricity by using PV modules. Applying solar energy instead of fossil fuels leads to...

This study aims to evaluate the sustainable energy performance of 36 OECD (Organization for Economic Cooperation and Development) countries. The sustainable energy performance evaluation of the countries was made with linear programming-based “DEA (Data Envelopment Analysis)” and multi-criteria decision-making-based “PROMETHEE (The Preference Ranki...

Nucleate pool steaming is an effective mode of transfer of heat that helps to reduce the use of fossil fuels and thus reduce pollution. Transfer of heat in nucleate pool steaming is examined to occur through the combination of natural convection, enhanced latent heat and convection transport. At the intermediate heat flux range, all three componen...

This paper experimentally investigated influential thermodynamic reservoir characteristics such as pressure, temperature, soaking time, core stimulation, number of cycles, shale particle size, and carbon dioxide phase during the cycling carbon dioxide injection. The carbon dioxide supercritical phase has reached the maximum recovery factor of 40%....

The turbulent convective thermal transfer in channel heat exchangers (CHEs) is studied numerically via the CFD (Computational Fluid Dynamics) method. Deflectors are inserted on the hot bottom walls of the heat channel to enhance the hydrothermal characteristics. Various shapes of in-line deflectors are considered, namely: rectangular (a/b = 0.00),...

Accurate modeling of heat pipes, as a two-phase thermal medium, is the main goal of several research works. Since the effective thermal conductivity of the heat pipes is dependent on different factors, the modeling procedure is complicated. The main techniques presented for modeling the heat pipes are numerical methods, i.e., computational fluid dy...

Zero liquid discharge (ZLD) has shown to be a promising technology to recycle water with good quality. The ZLD objective is to purify the water from all the liquid waste. The ZLD approach is concentrated on reducing wastewater for possible reuse. In conventional ZLD systems, thermal processes are fundamental. The biggest challenge to implement ther...